Hi,
This updated patch series relaxes landlock_add_rule(2) to accept file
descriptors opened without O_PATH. Using O_PATH is encouraged (as well
as O_CLOEXEC) but it should not be mandatory. Indeed, using already
opened FDs can be handy.
FYI, the COND_SYSCALL() fix is now in -next:
https://git.kernel.org/next/linux-next/c/7dfe553affd0d003c7535b7ba60d09193471ea9d
James, could you please update the -next tree?
The SLOC count is 1326 for security/landlock/ and 2589 for
tools/testing/selftest/landlock/ .
Test coverage for security/landlock/ is 93.6% of lines:
https://landlock.io/linux-lcov/landlock-v33/security/landlock/index.html
The code not covered only deals with internal kernel errors (e.g. memory
allocation), race conditions and safety checks that should not be
triggered. This series is being fuzzed by syzkaller (covering internal
kernel errors) that now supports Landlock:
https://github.com/google/syzkaller/pull/2380
syzkaller coverage is about 72% (ci-upstream-linux-next-kasan-gce-root):
https://syzkaller.appspot.com/upstream
The HTML documentation is available here:
https://landlock.io/linux-doc/landlock-v33/userspace-api/landlock.html
This series can be applied on top of v5.12-rc3 . This can be tested with
CONFIG_SECURITY_LANDLOCK, CONFIG_SAMPLE_LANDLOCK and by prepending
"landlock," to CONFIG_LSM. This patch series can be found in a Git
repository here:
https://github.com/landlock-lsm/linux/commits/landlock-v33
This patch series seems ready for upstream and I would really appreciate
final reviews.
Landlock LSM
============
The goal of Landlock is to enable to restrict ambient rights (e.g.
global filesystem access) for a set of processes. Because Landlock is a
stackable LSM [1], it makes possible to create safe security sandboxes
as new security layers in addition to the existing system-wide
access-controls. This kind of sandbox is expected to help mitigate the
security impact of bugs or unexpected/malicious behaviors in user-space
applications. Landlock empowers any process, including unprivileged
ones, to securely restrict themselves.
Landlock is inspired by seccomp-bpf but instead of filtering syscalls
and their raw arguments, a Landlock rule can restrict the use of kernel
objects like file hierarchies, according to the kernel semantic.
Landlock also takes inspiration from other OS sandbox mechanisms: XNU
Sandbox, FreeBSD Capsicum or OpenBSD Pledge/Unveil.
In this current form, Landlock misses some access-control features.
This enables to minimize this patch series and ease review. This series
still addresses multiple use cases, especially with the combined use of
seccomp-bpf: applications with built-in sandboxing, init systems,
security sandbox tools and security-oriented APIs [2].
[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/[email protected]/
Previous versions:
v32: https://lore.kernel.org/lkml/[email protected]/
v31: https://lore.kernel.org/lkml/[email protected]/
v30: https://lore.kernel.org/lkml/[email protected]/
v29: https://lore.kernel.org/lkml/[email protected]/
v28: https://lore.kernel.org/lkml/[email protected]/
v27: https://lore.kernel.org/lkml/[email protected]/
v26: https://lore.kernel.org/lkml/[email protected]/
v25: https://lore.kernel.org/lkml/[email protected]/
v24: https://lore.kernel.org/lkml/[email protected]/
v23: https://lore.kernel.org/lkml/[email protected]/
v22: https://lore.kernel.org/lkml/[email protected]/
v21: https://lore.kernel.org/lkml/[email protected]/
v20: https://lore.kernel.org/lkml/[email protected]/
v19: https://lore.kernel.org/lkml/[email protected]/
v18: https://lore.kernel.org/lkml/[email protected]/
v17: https://lore.kernel.org/lkml/[email protected]/
v16: https://lore.kernel.org/lkml/[email protected]/
v15: https://lore.kernel.org/lkml/[email protected]/
v14: https://lore.kernel.org/lkml/[email protected]/
v13: https://lore.kernel.org/lkml/[email protected]/
v12: https://lore.kernel.org/lkml/[email protected]/
v11: https://lore.kernel.org/lkml/[email protected]/
v10: https://lore.kernel.org/lkml/[email protected]/
v9: https://lore.kernel.org/lkml/[email protected]/
v8: https://lore.kernel.org/lkml/[email protected]/
v7: https://lore.kernel.org/lkml/[email protected]/
v6: https://lore.kernel.org/lkml/[email protected]/
v5: https://lore.kernel.org/lkml/[email protected]/
v4: https://lore.kernel.org/lkml/[email protected]/
v3: https://lore.kernel.org/lkml/[email protected]/
v2: https://lore.kernel.org/lkml/[email protected]/
v1: https://lore.kernel.org/kernel-hardening/[email protected]/
Casey Schaufler (1):
LSM: Infrastructure management of the superblock
Mickaël Salaün (11):
landlock: Add object management
landlock: Add ruleset and domain management
landlock: Set up the security framework and manage credentials
landlock: Add ptrace restrictions
fs,security: Add sb_delete hook
landlock: Support filesystem access-control
landlock: Add syscall implementations
arch: Wire up Landlock syscalls
selftests/landlock: Add user space tests
samples/landlock: Add a sandbox manager example
landlock: Add user and kernel documentation
Documentation/security/index.rst | 1 +
Documentation/security/landlock.rst | 85 +
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/landlock.rst | 311 ++
MAINTAINERS | 15 +
arch/Kconfig | 7 +
arch/alpha/kernel/syscalls/syscall.tbl | 3 +
arch/arm/tools/syscall.tbl | 3 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 6 +
arch/ia64/kernel/syscalls/syscall.tbl | 3 +
arch/m68k/kernel/syscalls/syscall.tbl | 3 +
arch/microblaze/kernel/syscalls/syscall.tbl | 3 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 3 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 3 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 3 +
arch/parisc/kernel/syscalls/syscall.tbl | 3 +
arch/powerpc/kernel/syscalls/syscall.tbl | 3 +
arch/s390/kernel/syscalls/syscall.tbl | 3 +
arch/sh/kernel/syscalls/syscall.tbl | 3 +
arch/sparc/kernel/syscalls/syscall.tbl | 3 +
arch/um/Kconfig | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 3 +
arch/x86/entry/syscalls/syscall_64.tbl | 3 +
arch/xtensa/kernel/syscalls/syscall.tbl | 3 +
fs/super.c | 1 +
include/linux/lsm_hook_defs.h | 1 +
include/linux/lsm_hooks.h | 4 +
include/linux/security.h | 4 +
include/linux/syscalls.h | 7 +
include/uapi/asm-generic/unistd.h | 8 +-
include/uapi/linux/landlock.h | 129 +
kernel/sys_ni.c | 5 +
samples/Kconfig | 7 +
samples/Makefile | 1 +
samples/landlock/.gitignore | 1 +
samples/landlock/Makefile | 13 +
samples/landlock/sandboxer.c | 238 ++
security/Kconfig | 11 +-
security/Makefile | 2 +
security/landlock/Kconfig | 21 +
security/landlock/Makefile | 4 +
security/landlock/common.h | 20 +
security/landlock/cred.c | 46 +
security/landlock/cred.h | 58 +
security/landlock/fs.c | 692 ++++
security/landlock/fs.h | 70 +
security/landlock/limits.h | 21 +
security/landlock/object.c | 67 +
security/landlock/object.h | 91 +
security/landlock/ptrace.c | 120 +
security/landlock/ptrace.h | 14 +
security/landlock/ruleset.c | 473 +++
security/landlock/ruleset.h | 165 +
security/landlock/setup.c | 40 +
security/landlock/setup.h | 18 +
security/landlock/syscalls.c | 442 +++
security/security.c | 51 +-
security/selinux/hooks.c | 58 +-
security/selinux/include/objsec.h | 6 +
security/selinux/ss/services.c | 3 +-
security/smack/smack.h | 6 +
security/smack/smack_lsm.c | 35 +-
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/landlock/.gitignore | 2 +
tools/testing/selftests/landlock/Makefile | 24 +
tools/testing/selftests/landlock/base_test.c | 219 ++
tools/testing/selftests/landlock/common.h | 183 ++
tools/testing/selftests/landlock/config | 7 +
tools/testing/selftests/landlock/fs_test.c | 2791 +++++++++++++++++
.../testing/selftests/landlock/ptrace_test.c | 337 ++
tools/testing/selftests/landlock/true.c | 5 +
72 files changed, 6922 insertions(+), 77 deletions(-)
create mode 100644 Documentation/security/landlock.rst
create mode 100644 Documentation/userspace-api/landlock.rst
create mode 100644 include/uapi/linux/landlock.h
create mode 100644 samples/landlock/.gitignore
create mode 100644 samples/landlock/Makefile
create mode 100644 samples/landlock/sandboxer.c
create mode 100644 security/landlock/Kconfig
create mode 100644 security/landlock/Makefile
create mode 100644 security/landlock/common.h
create mode 100644 security/landlock/cred.c
create mode 100644 security/landlock/cred.h
create mode 100644 security/landlock/fs.c
create mode 100644 security/landlock/fs.h
create mode 100644 security/landlock/limits.h
create mode 100644 security/landlock/object.c
create mode 100644 security/landlock/object.h
create mode 100644 security/landlock/ptrace.c
create mode 100644 security/landlock/ptrace.h
create mode 100644 security/landlock/ruleset.c
create mode 100644 security/landlock/ruleset.h
create mode 100644 security/landlock/setup.c
create mode 100644 security/landlock/setup.h
create mode 100644 security/landlock/syscalls.c
create mode 100644 tools/testing/selftests/landlock/.gitignore
create mode 100644 tools/testing/selftests/landlock/Makefile
create mode 100644 tools/testing/selftests/landlock/base_test.c
create mode 100644 tools/testing/selftests/landlock/common.h
create mode 100644 tools/testing/selftests/landlock/config
create mode 100644 tools/testing/selftests/landlock/fs_test.c
create mode 100644 tools/testing/selftests/landlock/ptrace_test.c
create mode 100644 tools/testing/selftests/landlock/true.c
base-commit: 1e28eed17697bcf343c6743f0028cc3b5dd88bf0
--
2.30.2
From: Mickaël Salaün <[email protected]>
A Landlock object enables to identify a kernel object (e.g. an inode).
A Landlock rule is a set of access rights allowed on an object. Rules
are grouped in rulesets that may be tied to a set of processes (i.e.
subjects) to enforce a scoped access-control (i.e. a domain).
Because Landlock's goal is to empower any process (especially
unprivileged ones) to sandbox themselves, we cannot rely on a
system-wide object identification such as file extended attributes.
Indeed, we need innocuous, composable and modular access-controls.
The main challenge with these constraints is to identify kernel objects
while this identification is useful (i.e. when a security policy makes
use of this object). But this identification data should be freed once
no policy is using it. This ephemeral tagging should not and may not be
written in the filesystem. We then need to manage the lifetime of a
rule according to the lifetime of its objects. To avoid a global lock,
this implementation make use of RCU and counters to safely reference
objects.
A following commit uses this generic object management for inodes.
Cc: James Morris <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v31:
* Fix typo.
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Improve Kconfig description (suggested by Serge Hallyn).
* Add Acked-by Serge Hallyn.
* Clean up comment.
Changes since v27:
* Update Kconfig for landlock_restrict_self(2).
* Cosmetic fixes: use 80 columns in Kconfig and align Makefile
declarations.
Changes since v26:
* Update Kconfig for landlock_enforce_ruleset_self(2).
* Fix spelling.
Changes since v24:
* Fix typo in comment (spotted by Jann Horn).
* Add Reviewed-by Jann Horn.
Changes since v23:
* Update landlock_create_object() to return error codes instead of NULL.
This help error handling in callers.
* When using make oldconfig with a previous configuration already
including the CONFIG_LSM variable, no question is asked to update its
content. Update the Kconfig help to warn about LSM stacking
configuration.
* Constify variable (spotted by Vincent Dagonneau).
Changes since v22:
* Fix spelling (spotted by Jann Horn).
Changes since v21:
* Update Kconfig help.
* Clean up comments.
Changes since v18:
* Account objects to kmemcg.
Changes since v14:
* Simplify the object, rule and ruleset management at the expense of a
less aggressive memory freeing (contributed by Jann Horn, with
additional modifications):
- Remove object->list aggregating the rules tied to an object.
- Remove landlock_get_object(), landlock_drop_object(),
{get,put}_object_cleaner() and landlock_rule_is_disabled().
- Rewrite landlock_put_object() to use a more simple mechanism
(no tricky RCU).
- Replace enum landlock_object_type and landlock_release_object() with
landlock_object_underops->release()
- Adjust unions and Sparse annotations.
Cf. https://lore.kernel.org/lkml/CAG48ez21bEn0wL1bbmTiiu8j9jP5iEWtHOwz4tURUJ+ki0ydYw@mail.gmail.com/
* Merge struct landlock_rule into landlock_ruleset_elem to simplify the
rule management.
* Constify variables.
* Improve kernel documentation.
* Cosmetic variable renames.
* Remove the "default" in the Kconfig (suggested by Jann Horn).
* Only use refcount_inc() through getter helpers.
* Update Kconfig description.
Changes since v13:
* New dedicated implementation, removing the need for eBPF.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
MAINTAINERS | 10 +++++
security/Kconfig | 1 +
security/Makefile | 2 +
security/landlock/Kconfig | 21 +++++++++
security/landlock/Makefile | 3 ++
security/landlock/object.c | 67 ++++++++++++++++++++++++++++
security/landlock/object.h | 91 ++++++++++++++++++++++++++++++++++++++
7 files changed, 195 insertions(+)
create mode 100644 security/landlock/Kconfig
create mode 100644 security/landlock/Makefile
create mode 100644 security/landlock/object.c
create mode 100644 security/landlock/object.h
diff --git a/MAINTAINERS b/MAINTAINERS
index aa84121c5611..87a2738dfdec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9997,6 +9997,16 @@ F: net/core/sock_map.c
F: net/ipv4/tcp_bpf.c
F: net/ipv4/udp_bpf.c
+LANDLOCK SECURITY MODULE
+M: Mickaël Salaün <[email protected]>
+L: [email protected]
+S: Supported
+W: https://landlock.io
+T: git https://github.com/landlock-lsm/linux.git
+F: security/landlock/
+K: landlock
+K: LANDLOCK
+
LANTIQ / INTEL Ethernet drivers
M: Hauke Mehrtens <[email protected]>
L: [email protected]
diff --git a/security/Kconfig b/security/Kconfig
index 7561f6f99f1d..15a4342b5d01 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -238,6 +238,7 @@ source "security/loadpin/Kconfig"
source "security/yama/Kconfig"
source "security/safesetid/Kconfig"
source "security/lockdown/Kconfig"
+source "security/landlock/Kconfig"
source "security/integrity/Kconfig"
diff --git a/security/Makefile b/security/Makefile
index 3baf435de541..47e432900e24 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -13,6 +13,7 @@ subdir-$(CONFIG_SECURITY_LOADPIN) += loadpin
subdir-$(CONFIG_SECURITY_SAFESETID) += safesetid
subdir-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown
subdir-$(CONFIG_BPF_LSM) += bpf
+subdir-$(CONFIG_SECURITY_LANDLOCK) += landlock
# always enable default capabilities
obj-y += commoncap.o
@@ -32,6 +33,7 @@ obj-$(CONFIG_SECURITY_SAFESETID) += safesetid/
obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown/
obj-$(CONFIG_CGROUPS) += device_cgroup.o
obj-$(CONFIG_BPF_LSM) += bpf/
+obj-$(CONFIG_SECURITY_LANDLOCK) += landlock/
# Object integrity file lists
subdir-$(CONFIG_INTEGRITY) += integrity
diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig
new file mode 100644
index 000000000000..c1e862a38410
--- /dev/null
+++ b/security/landlock/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config SECURITY_LANDLOCK
+ bool "Landlock support"
+ depends on SECURITY
+ select SECURITY_PATH
+ help
+ Landlock is a sandboxing mechanism that enables processes to restrict
+ themselves (and their future children) by gradually enforcing
+ tailored access control policies. A Landlock security policy is a
+ set of access rights (e.g. open a file in read-only, make a
+ directory, etc.) tied to a file hierarchy. Such policy can be
+ configured and enforced by any processes for themselves using the
+ dedicated system calls: landlock_create_ruleset(),
+ landlock_add_rule(), and landlock_restrict_self().
+
+ See Documentation/userspace-api/landlock.rst for further information.
+
+ If you are unsure how to answer this question, answer N. Otherwise,
+ you should also prepend "landlock," to the content of CONFIG_LSM to
+ enable Landlock at boot time.
diff --git a/security/landlock/Makefile b/security/landlock/Makefile
new file mode 100644
index 000000000000..cb6deefbf4c0
--- /dev/null
+++ b/security/landlock/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o
+
+landlock-y := object.o
diff --git a/security/landlock/object.c b/security/landlock/object.c
new file mode 100644
index 000000000000..d674fdf9ff04
--- /dev/null
+++ b/security/landlock/object.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - Object management
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#include <linux/bug.h>
+#include <linux/compiler_types.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/rcupdate.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "object.h"
+
+struct landlock_object *landlock_create_object(
+ const struct landlock_object_underops *const underops,
+ void *const underobj)
+{
+ struct landlock_object *new_object;
+
+ if (WARN_ON_ONCE(!underops || !underobj))
+ return ERR_PTR(-ENOENT);
+ new_object = kzalloc(sizeof(*new_object), GFP_KERNEL_ACCOUNT);
+ if (!new_object)
+ return ERR_PTR(-ENOMEM);
+ refcount_set(&new_object->usage, 1);
+ spin_lock_init(&new_object->lock);
+ new_object->underops = underops;
+ new_object->underobj = underobj;
+ return new_object;
+}
+
+/*
+ * The caller must own the object (i.e. thanks to object->usage) to safely put
+ * it.
+ */
+void landlock_put_object(struct landlock_object *const object)
+{
+ /*
+ * The call to @object->underops->release(object) might sleep, e.g.
+ * because of iput().
+ */
+ might_sleep();
+ if (!object)
+ return;
+
+ /*
+ * If the @object's refcount cannot drop to zero, we can just decrement
+ * the refcount without holding a lock. Otherwise, the decrement must
+ * happen under @object->lock for synchronization with things like
+ * get_inode_object().
+ */
+ if (refcount_dec_and_lock(&object->usage, &object->lock)) {
+ __acquire(&object->lock);
+ /*
+ * With @object->lock initially held, remove the reference from
+ * @object->underobj to @object (if it still exists).
+ */
+ object->underops->release(object);
+ kfree_rcu(object, rcu_free);
+ }
+}
diff --git a/security/landlock/object.h b/security/landlock/object.h
new file mode 100644
index 000000000000..3f80674c6c8d
--- /dev/null
+++ b/security/landlock/object.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - Object management
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_OBJECT_H
+#define _SECURITY_LANDLOCK_OBJECT_H
+
+#include <linux/compiler_types.h>
+#include <linux/refcount.h>
+#include <linux/spinlock.h>
+
+struct landlock_object;
+
+/**
+ * struct landlock_object_underops - Operations on an underlying object
+ */
+struct landlock_object_underops {
+ /**
+ * @release: Releases the underlying object (e.g. iput() for an inode).
+ */
+ void (*release)(struct landlock_object *const object)
+ __releases(object->lock);
+};
+
+/**
+ * struct landlock_object - Security blob tied to a kernel object
+ *
+ * The goal of this structure is to enable to tie a set of ephemeral access
+ * rights (pertaining to different domains) to a kernel object (e.g an inode)
+ * in a safe way. This implies to handle concurrent use and modification.
+ *
+ * The lifetime of a &struct landlock_object depends on the rules referring to
+ * it.
+ */
+struct landlock_object {
+ /**
+ * @usage: This counter is used to tie an object to the rules matching
+ * it or to keep it alive while adding a new rule. If this counter
+ * reaches zero, this struct must not be modified, but this counter can
+ * still be read from within an RCU read-side critical section. When
+ * adding a new rule to an object with a usage counter of zero, we must
+ * wait until the pointer to this object is set to NULL (or recycled).
+ */
+ refcount_t usage;
+ /**
+ * @lock: Protects against concurrent modifications. This lock must be
+ * held from the time @usage drops to zero until any weak references
+ * from @underobj to this object have been cleaned up.
+ *
+ * Lock ordering: inode->i_lock nests inside this.
+ */
+ spinlock_t lock;
+ /**
+ * @underobj: Used when cleaning up an object and to mark an object as
+ * tied to its underlying kernel structure. This pointer is protected
+ * by @lock. Cf. landlock_release_inodes() and release_inode().
+ */
+ void *underobj;
+ union {
+ /**
+ * @rcu_free: Enables lockless use of @usage, @lock and
+ * @underobj from within an RCU read-side critical section.
+ * @rcu_free and @underops are only used by
+ * landlock_put_object().
+ */
+ struct rcu_head rcu_free;
+ /**
+ * @underops: Enables landlock_put_object() to release the
+ * underlying object (e.g. inode).
+ */
+ const struct landlock_object_underops *underops;
+ };
+};
+
+struct landlock_object *landlock_create_object(
+ const struct landlock_object_underops *const underops,
+ void *const underobj);
+
+void landlock_put_object(struct landlock_object *const object);
+
+static inline void landlock_get_object(struct landlock_object *const object)
+{
+ if (object)
+ refcount_inc(&object->usage);
+}
+
+#endif /* _SECURITY_LANDLOCK_OBJECT_H */
--
2.30.2
From: Mickaël Salaün <[email protected]>
Process's credentials point to a Landlock domain, which is underneath
implemented with a ruleset. In the following commits, this domain is
used to check and enforce the ptrace and filesystem security policies.
A domain is inherited from a parent to its child the same way a thread
inherits a seccomp policy.
Cc: James Morris <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Add Acked-by Serge Hallyn.
Changes since v25:
* Rename function to landlock_add_cred_hooks().
Changes since v23:
* Add an early check for the current domain in hook_cred_free() to avoid
superfluous call.
* Cosmetic cleanup to make the code more readable.
Changes since v22:
* Add Reviewed-by Jann Horn.
Changes since v21:
* Fix copyright dates.
Changes since v17:
* Constify returned domain pointers from landlock_get_current_domain()
and landlock_get_task_domain() helpers.
Changes since v15:
* Optimize landlocked() for current thread.
* Display the greeting message when everything is initialized.
Changes since v14:
* Uses pr_fmt from common.h .
* Constify variables.
* Remove useless NULL initialization.
Changes since v13:
* totally get ride of the seccomp dependency
* only keep credential management and LSM setup.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
security/Kconfig | 10 +++----
security/landlock/Makefile | 3 +-
security/landlock/common.h | 20 +++++++++++++
security/landlock/cred.c | 46 ++++++++++++++++++++++++++++++
security/landlock/cred.h | 58 ++++++++++++++++++++++++++++++++++++++
security/landlock/setup.c | 31 ++++++++++++++++++++
security/landlock/setup.h | 16 +++++++++++
7 files changed, 178 insertions(+), 6 deletions(-)
create mode 100644 security/landlock/common.h
create mode 100644 security/landlock/cred.c
create mode 100644 security/landlock/cred.h
create mode 100644 security/landlock/setup.c
create mode 100644 security/landlock/setup.h
diff --git a/security/Kconfig b/security/Kconfig
index 15a4342b5d01..0ced7fd33e4d 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -278,11 +278,11 @@ endchoice
config LSM
string "Ordered list of enabled LSMs"
- default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
- default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
- default "lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
- default "lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
- default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
+ default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
+ default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
+ default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
+ default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
+ default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
help
A comma-separated list of LSMs, in initialization order.
Any LSMs left off this list will be ignored. This can be
diff --git a/security/landlock/Makefile b/security/landlock/Makefile
index d846eba445bb..041ea242e627 100644
--- a/security/landlock/Makefile
+++ b/security/landlock/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o
-landlock-y := object.o ruleset.o
+landlock-y := setup.o object.o ruleset.o \
+ cred.o
diff --git a/security/landlock/common.h b/security/landlock/common.h
new file mode 100644
index 000000000000..5dc0fe15707d
--- /dev/null
+++ b/security/landlock/common.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - Common constants and helpers
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_COMMON_H
+#define _SECURITY_LANDLOCK_COMMON_H
+
+#define LANDLOCK_NAME "landlock"
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) LANDLOCK_NAME ": " fmt
+
+#endif /* _SECURITY_LANDLOCK_COMMON_H */
diff --git a/security/landlock/cred.c b/security/landlock/cred.c
new file mode 100644
index 000000000000..6725af24c684
--- /dev/null
+++ b/security/landlock/cred.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - Credential hooks
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#include <linux/cred.h>
+#include <linux/lsm_hooks.h>
+
+#include "common.h"
+#include "cred.h"
+#include "ruleset.h"
+#include "setup.h"
+
+static int hook_cred_prepare(struct cred *const new,
+ const struct cred *const old, const gfp_t gfp)
+{
+ struct landlock_ruleset *const old_dom = landlock_cred(old)->domain;
+
+ if (old_dom) {
+ landlock_get_ruleset(old_dom);
+ landlock_cred(new)->domain = old_dom;
+ }
+ return 0;
+}
+
+static void hook_cred_free(struct cred *const cred)
+{
+ struct landlock_ruleset *const dom = landlock_cred(cred)->domain;
+
+ if (dom)
+ landlock_put_ruleset_deferred(dom);
+}
+
+static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
+ LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
+ LSM_HOOK_INIT(cred_free, hook_cred_free),
+};
+
+__init void landlock_add_cred_hooks(void)
+{
+ security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
+ LANDLOCK_NAME);
+}
diff --git a/security/landlock/cred.h b/security/landlock/cred.h
new file mode 100644
index 000000000000..5f99d3decade
--- /dev/null
+++ b/security/landlock/cred.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - Credential hooks
+ *
+ * Copyright © 2019-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2019-2020 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_CRED_H
+#define _SECURITY_LANDLOCK_CRED_H
+
+#include <linux/cred.h>
+#include <linux/init.h>
+#include <linux/rcupdate.h>
+
+#include "ruleset.h"
+#include "setup.h"
+
+struct landlock_cred_security {
+ struct landlock_ruleset *domain;
+};
+
+static inline struct landlock_cred_security *landlock_cred(
+ const struct cred *cred)
+{
+ return cred->security + landlock_blob_sizes.lbs_cred;
+}
+
+static inline const struct landlock_ruleset *landlock_get_current_domain(void)
+{
+ return landlock_cred(current_cred())->domain;
+}
+
+/*
+ * The call needs to come from an RCU read-side critical section.
+ */
+static inline const struct landlock_ruleset *landlock_get_task_domain(
+ const struct task_struct *const task)
+{
+ return landlock_cred(__task_cred(task))->domain;
+}
+
+static inline bool landlocked(const struct task_struct *const task)
+{
+ bool has_dom;
+
+ if (task == current)
+ return !!landlock_get_current_domain();
+
+ rcu_read_lock();
+ has_dom = !!landlock_get_task_domain(task);
+ rcu_read_unlock();
+ return has_dom;
+}
+
+__init void landlock_add_cred_hooks(void);
+
+#endif /* _SECURITY_LANDLOCK_CRED_H */
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
new file mode 100644
index 000000000000..8661112fb238
--- /dev/null
+++ b/security/landlock/setup.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - Security framework setup
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#include <linux/init.h>
+#include <linux/lsm_hooks.h>
+
+#include "common.h"
+#include "cred.h"
+#include "setup.h"
+
+struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
+ .lbs_cred = sizeof(struct landlock_cred_security),
+};
+
+static int __init landlock_init(void)
+{
+ landlock_add_cred_hooks();
+ pr_info("Up and running.\n");
+ return 0;
+}
+
+DEFINE_LSM(LANDLOCK_NAME) = {
+ .name = LANDLOCK_NAME,
+ .init = landlock_init,
+ .blobs = &landlock_blob_sizes,
+};
diff --git a/security/landlock/setup.h b/security/landlock/setup.h
new file mode 100644
index 000000000000..9fdbf33fcc33
--- /dev/null
+++ b/security/landlock/setup.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - Security framework setup
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_SETUP_H
+#define _SECURITY_LANDLOCK_SETUP_H
+
+#include <linux/lsm_hooks.h>
+
+extern struct lsm_blob_sizes landlock_blob_sizes;
+
+#endif /* _SECURITY_LANDLOCK_SETUP_H */
--
2.30.2
From: Mickaël Salaün <[email protected]>
Add a basic sandbox tool to launch a command which can only access a
list of file hierarchies in a read-only or read-write way.
Cc: James Morris <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Simplify Kconfig option title.
Changes since v27:
* Add samples/landlock/ to MAINTAINERS.
* Update landlock_restrict_self(2).
* Tweak Kconfig title and description.
Changes since v25:
* Improve comments and fix help (suggested by Jann Horn).
* Add a safeguard for errno check (suggested by Jann Horn).
* Allows users to not use all possible restrictions (e.g. use LL_FS_RO
without LL_FS_RW).
* Update syscall names.
* Improve Makefile:
- Replace hostprogs/always-y with userprogs-always-y, available since
commit faabed295ccc ("kbuild: introduce hostprogs-always-y and
userprogs-always-y").
- Depends on CC_CAN_LINK.
* Add Reviewed-by Jann Horn.
Changes since v25:
* Remove useless errno set in the syscall wrappers.
* Cosmetic variable renames.
Changes since v23:
* Re-add hints to help users understand the required kernel
configuration. This was removed with the removal of
landlock_get_features(2).
Changes since v21:
* Remove LANDLOCK_ACCESS_FS_CHROOT.
* Clean up help.
Changes since v20:
* Update with new syscalls and type names.
* Update errno check for EOPNOTSUPP.
* Use the full syscall interfaces: explicitely set the "flags" field to
zero.
Changes since v19:
* Update with the new Landlock syscalls.
* Comply with commit 5f2fb52fac15 ("kbuild: rename hostprogs-y/always to
hostprogs/always-y").
Changes since v16:
* Switch syscall attribute pointer and size arguments.
Changes since v15:
* Update access right names.
* Properly assign access right to files according to the new related
syscall restriction.
* Replace "select" with "depends on" HEADERS_INSTALL (suggested by Randy
Dunlap).
Changes since v14:
* Fix Kconfig dependency.
* Remove access rights that may be required for FD-only requests:
mmap, truncate, getattr, lock, chmod, chown, chgrp, ioctl.
* Fix useless hardcoded syscall number.
* Use execvpe().
* Follow symlinks.
* Extend help with common file paths.
* Constify variables.
* Clean up comments.
* Improve error message.
Changes since v11:
* Add back the filesystem sandbox manager and update it to work with the
new Landlock syscall.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
MAINTAINERS | 1 +
samples/Kconfig | 7 ++
samples/Makefile | 1 +
samples/landlock/.gitignore | 1 +
samples/landlock/Makefile | 13 ++
samples/landlock/sandboxer.c | 238 +++++++++++++++++++++++++++++++++++
6 files changed, 261 insertions(+)
create mode 100644 samples/landlock/.gitignore
create mode 100644 samples/landlock/Makefile
create mode 100644 samples/landlock/sandboxer.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 8cab5854844e..88175ed1f315 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10004,6 +10004,7 @@ S: Supported
W: https://landlock.io
T: git https://github.com/landlock-lsm/linux.git
F: include/uapi/linux/landlock.h
+F: samples/landlock/
F: security/landlock/
F: tools/testing/selftests/landlock/
K: landlock
diff --git a/samples/Kconfig b/samples/Kconfig
index e76cdfc50e25..b5a1a7aa7e23 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -124,6 +124,13 @@ config SAMPLE_HIDRAW
bool "hidraw sample"
depends on CC_CAN_LINK && HEADERS_INSTALL
+config SAMPLE_LANDLOCK
+ bool "Landlock example"
+ depends on CC_CAN_LINK && HEADERS_INSTALL
+ help
+ Build a simple Landlock sandbox manager able to start a process
+ restricted by a user-defined filesystem access control policy.
+
config SAMPLE_PIDFD
bool "pidfd sample"
depends on CC_CAN_LINK && HEADERS_INSTALL
diff --git a/samples/Makefile b/samples/Makefile
index c3392a595e4b..087e0988ccc5 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_SAMPLE_KDB) += kdb/
obj-$(CONFIG_SAMPLE_KFIFO) += kfifo/
obj-$(CONFIG_SAMPLE_KOBJECT) += kobject/
obj-$(CONFIG_SAMPLE_KPROBES) += kprobes/
+subdir-$(CONFIG_SAMPLE_LANDLOCK) += landlock
obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch/
subdir-$(CONFIG_SAMPLE_PIDFD) += pidfd
obj-$(CONFIG_SAMPLE_QMI_CLIENT) += qmi/
diff --git a/samples/landlock/.gitignore b/samples/landlock/.gitignore
new file mode 100644
index 000000000000..f43668b2d318
--- /dev/null
+++ b/samples/landlock/.gitignore
@@ -0,0 +1 @@
+/sandboxer
diff --git a/samples/landlock/Makefile b/samples/landlock/Makefile
new file mode 100644
index 000000000000..5d601e51c2eb
--- /dev/null
+++ b/samples/landlock/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+userprogs-always-y := sandboxer
+
+userccflags += -I usr/include
+
+.PHONY: all clean
+
+all:
+ $(MAKE) -C ../.. samples/landlock/
+
+clean:
+ $(MAKE) -C ../.. M=samples/landlock/ clean
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
new file mode 100644
index 000000000000..7a15910d2171
--- /dev/null
+++ b/samples/landlock/sandboxer.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Simple Landlock sandbox manager able to launch a process restricted by a
+ * user-defined filesystem access control policy.
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2020 ANSSI
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <linux/prctl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#ifndef landlock_create_ruleset
+static inline int landlock_create_ruleset(
+ const struct landlock_ruleset_attr *const attr,
+ const size_t size, const __u32 flags)
+{
+ return syscall(__NR_landlock_create_ruleset, attr, size, flags);
+}
+#endif
+
+#ifndef landlock_add_rule
+static inline int landlock_add_rule(const int ruleset_fd,
+ const enum landlock_rule_type rule_type,
+ const void *const rule_attr, const __u32 flags)
+{
+ return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type,
+ rule_attr, flags);
+}
+#endif
+
+#ifndef landlock_restrict_self
+static inline int landlock_restrict_self(const int ruleset_fd,
+ const __u32 flags)
+{
+ return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
+}
+#endif
+
+#define ENV_FS_RO_NAME "LL_FS_RO"
+#define ENV_FS_RW_NAME "LL_FS_RW"
+#define ENV_PATH_TOKEN ":"
+
+static int parse_path(char *env_path, const char ***const path_list)
+{
+ int i, num_paths = 0;
+
+ if (env_path) {
+ num_paths++;
+ for (i = 0; env_path[i]; i++) {
+ if (env_path[i] == ENV_PATH_TOKEN[0])
+ num_paths++;
+ }
+ }
+ *path_list = malloc(num_paths * sizeof(**path_list));
+ for (i = 0; i < num_paths; i++)
+ (*path_list)[i] = strsep(&env_path, ENV_PATH_TOKEN);
+
+ return num_paths;
+}
+
+#define ACCESS_FILE ( \
+ LANDLOCK_ACCESS_FS_EXECUTE | \
+ LANDLOCK_ACCESS_FS_WRITE_FILE | \
+ LANDLOCK_ACCESS_FS_READ_FILE)
+
+static int populate_ruleset(
+ const char *const env_var, const int ruleset_fd,
+ const __u64 allowed_access)
+{
+ int num_paths, i, ret = 1;
+ char *env_path_name;
+ const char **path_list = NULL;
+ struct landlock_path_beneath_attr path_beneath = {
+ .parent_fd = -1,
+ };
+
+ env_path_name = getenv(env_var);
+ if (!env_path_name) {
+ /* Prevents users to forget a setting. */
+ fprintf(stderr, "Missing environment variable %s\n", env_var);
+ return 1;
+ }
+ env_path_name = strdup(env_path_name);
+ unsetenv(env_var);
+ num_paths = parse_path(env_path_name, &path_list);
+ if (num_paths == 1 && path_list[0][0] == '\0') {
+ /*
+ * Allows to not use all possible restrictions (e.g. use
+ * LL_FS_RO without LL_FS_RW).
+ */
+ ret = 0;
+ goto out_free_name;
+ }
+
+ for (i = 0; i < num_paths; i++) {
+ struct stat statbuf;
+
+ path_beneath.parent_fd = open(path_list[i], O_PATH |
+ O_CLOEXEC);
+ if (path_beneath.parent_fd < 0) {
+ fprintf(stderr, "Failed to open \"%s\": %s\n",
+ path_list[i],
+ strerror(errno));
+ goto out_free_name;
+ }
+ if (fstat(path_beneath.parent_fd, &statbuf)) {
+ close(path_beneath.parent_fd);
+ goto out_free_name;
+ }
+ path_beneath.allowed_access = allowed_access;
+ if (!S_ISDIR(statbuf.st_mode))
+ path_beneath.allowed_access &= ACCESS_FILE;
+ if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0)) {
+ fprintf(stderr, "Failed to update the ruleset with \"%s\": %s\n",
+ path_list[i], strerror(errno));
+ close(path_beneath.parent_fd);
+ goto out_free_name;
+ }
+ close(path_beneath.parent_fd);
+ }
+ ret = 0;
+
+out_free_name:
+ free(env_path_name);
+ return ret;
+}
+
+#define ACCESS_FS_ROUGHLY_READ ( \
+ LANDLOCK_ACCESS_FS_EXECUTE | \
+ LANDLOCK_ACCESS_FS_READ_FILE | \
+ LANDLOCK_ACCESS_FS_READ_DIR)
+
+#define ACCESS_FS_ROUGHLY_WRITE ( \
+ LANDLOCK_ACCESS_FS_WRITE_FILE | \
+ LANDLOCK_ACCESS_FS_REMOVE_DIR | \
+ LANDLOCK_ACCESS_FS_REMOVE_FILE | \
+ LANDLOCK_ACCESS_FS_MAKE_CHAR | \
+ LANDLOCK_ACCESS_FS_MAKE_DIR | \
+ LANDLOCK_ACCESS_FS_MAKE_REG | \
+ LANDLOCK_ACCESS_FS_MAKE_SOCK | \
+ LANDLOCK_ACCESS_FS_MAKE_FIFO | \
+ LANDLOCK_ACCESS_FS_MAKE_BLOCK | \
+ LANDLOCK_ACCESS_FS_MAKE_SYM)
+
+int main(const int argc, char *const argv[], char *const *const envp)
+{
+ const char *cmd_path;
+ char *const *cmd_argv;
+ int ruleset_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_FS_ROUGHLY_READ |
+ ACCESS_FS_ROUGHLY_WRITE,
+ };
+
+ if (argc < 2) {
+ fprintf(stderr, "usage: %s=\"...\" %s=\"...\" %s <cmd> [args]...\n\n",
+ ENV_FS_RO_NAME, ENV_FS_RW_NAME, argv[0]);
+ fprintf(stderr, "Launch a command in a restricted environment.\n\n");
+ fprintf(stderr, "Environment variables containing paths, "
+ "each separated by a colon:\n");
+ fprintf(stderr, "* %s: list of paths allowed to be used in a read-only way.\n",
+ ENV_FS_RO_NAME);
+ fprintf(stderr, "* %s: list of paths allowed to be used in a read-write way.\n",
+ ENV_FS_RW_NAME);
+ fprintf(stderr, "\nexample:\n"
+ "%s=\"/bin:/lib:/usr:/proc:/etc:/dev/urandom\" "
+ "%s=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" "
+ "%s bash -i\n",
+ ENV_FS_RO_NAME, ENV_FS_RW_NAME, argv[0]);
+ return 1;
+ }
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ if (ruleset_fd < 0) {
+ const int err = errno;
+
+ perror("Failed to create a ruleset");
+ switch (err) {
+ case ENOSYS:
+ fprintf(stderr, "Hint: Landlock is not supported by the current kernel. "
+ "To support it, build the kernel with "
+ "CONFIG_SECURITY_LANDLOCK=y and prepend "
+ "\"landlock,\" to the content of CONFIG_LSM.\n");
+ break;
+ case EOPNOTSUPP:
+ fprintf(stderr, "Hint: Landlock is currently disabled. "
+ "It can be enabled in the kernel configuration by "
+ "prepending \"landlock,\" to the content of CONFIG_LSM, "
+ "or at boot time by setting the same content to the "
+ "\"lsm\" kernel parameter.\n");
+ break;
+ }
+ return 1;
+ }
+ if (populate_ruleset(ENV_FS_RO_NAME, ruleset_fd,
+ ACCESS_FS_ROUGHLY_READ)) {
+ goto err_close_ruleset;
+ }
+ if (populate_ruleset(ENV_FS_RW_NAME, ruleset_fd,
+ ACCESS_FS_ROUGHLY_READ | ACCESS_FS_ROUGHLY_WRITE)) {
+ goto err_close_ruleset;
+ }
+ if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+ perror("Failed to restrict privileges");
+ goto err_close_ruleset;
+ }
+ if (landlock_restrict_self(ruleset_fd, 0)) {
+ perror("Failed to enforce ruleset");
+ goto err_close_ruleset;
+ }
+ close(ruleset_fd);
+
+ cmd_path = argv[1];
+ cmd_argv = argv + 1;
+ execvpe(cmd_path, cmd_argv, envp);
+ fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path,
+ strerror(errno));
+ fprintf(stderr, "Hint: access to the binary, the interpreter or "
+ "shared libraries may be denied.\n");
+ return 1;
+
+err_close_ruleset:
+ close(ruleset_fd);
+ return 1;
+}
--
2.30.2
From: Mickaël Salaün <[email protected]>
These 3 system calls are designed to be used by unprivileged processes
to sandbox themselves:
* landlock_create_ruleset(2): Creates a ruleset and returns its file
descriptor.
* landlock_add_rule(2): Adds a rule (e.g. file hierarchy access) to a
ruleset, identified by the dedicated file descriptor.
* landlock_restrict_self(2): Enforces a ruleset on the calling thread
and its future children (similar to seccomp). This syscall has the
same usage restrictions as seccomp(2): the caller must have the
no_new_privs attribute set or have CAP_SYS_ADMIN in the current user
namespace.
All these syscalls have a "flags" argument (not currently used) to
enable extensibility.
Here are the motivations for these new syscalls:
* A sandboxed process may not have access to file systems, including
/dev, /sys or /proc, but it should still be able to add more
restrictions to itself.
* Neither prctl(2) nor seccomp(2) (which was used in a previous version)
fit well with the current definition of a Landlock security policy.
All passed structs (attributes) are checked at build time to ensure that
they don't contain holes and that they are aligned the same way for each
architecture.
See the user and kernel documentation for more details (provided by a
following commit):
* Documentation/userspace-api/landlock.rst
* Documentation/security/landlock.rst
Cc: Arnd Bergmann <[email protected]>
Cc: James Morris <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v32:
* Do not force to open files passed to landlock_add_rule(2) with O_PATH.
It is encouraged to do so, as well as for O_CLOEXEC, but it should not
be mandatory. Indeed, some use cases can legitimately reuse file
descriptors (e.g. to list the content of a directory).
Changes since v29:
* Rebase on v5.12-rc3 and fix trivial conflict with mount_setattr(2).
Changes since v28:
* Add Acked-by Serge Hallyn.
* Add extra check to be sure to not include ruleset FDs in a dependency
of a ruleset (e.g. a path_beneath rule). This case was already
forbiden thanks to FMODE_PATH and other flags check, but it makes it
explicit now.
Changes since v27:
* Forbid creation of rules with an empty allowed_access value because
they are now ignored (since v26) in path walks.
* Rename landlock_enforce_ruleset_self(2) to landlock_restrict_self(2):
shorter and consistent with the two other syscalls (i.e. verb + direct
object).
* Update ruleset access check according to the new access stack.
* Improve landlock_add_rule(2) documentation.
* Fix comment.
* Remove Reviewed-by Jann Horn because of the above changes.
Changes since v26:
* Rename landlock_enforce_ruleset_current(2) to
landlock_enforce_ruleset_self(2). "current" makes sense for a kernel
developer, but much less from a user space developer stand point.
"self" is widely used to refer to the current task (e.g. /proc/self).
"current" may refer to temporal properties, which could be added later
to this syscall flags (cf. /proc/self/attr/{current,exec}).
* Simplify build_check_abi().
* Rename syscall.c to syscalls.c .
* Use less ambiguous comments.
* Fix spelling.
Changes since v25:
* Revert build_check_abi() as non-inline to trigger a warning if it is
not called.
* Use the new limit names.
Changes since v24:
* Add Reviewed-by: Jann Horn <[email protected]>
* Set build_check_abi() as inline.
Changes since v23:
* Rewrite get_ruleset_from_fd() to please the 0-DAY CI Kernel Test
Service that reported an uninitialized variable (false positive):
https://lore.kernel.org/linux-security-module/[email protected]/
Anyway, it is cleaner like this.
* Add a comment about E2BIG which can be returned by
landlock_enforce_ruleset_current(2) when there is no more room for
another stacked ruleset (i.e. domain).
Changes since v22:
* Replace security_capable() with ns_capable_noaudit() (suggested by
Jann Horn) and explicitly return EPERM.
* Fix landlock_enforce_ruleset_current(2)'s out_put_creds (spotted by
Jann Horn).
* Add __always_inline to copy_min_struct_from_user() to make its
BUILD_BUG_ON() checks reliable (suggested by Jann Horn).
* Simplify path assignation in get_path_from_fd() (suggested by Jann
Horn).
* Fix spelling (spotted by Jann Horn).
Changes since v21:
* Fix and improve comments.
Changes since v20:
* Remove two arguments to landlock_enforce_ruleset(2) (requested by Arnd
Bergmann) and rename it to landlock_enforce_ruleset_current(2): remove
the enum landlock_target_type and the target file descriptor (not used
for now). A ruleset can only be enforced on the current thread.
* Remove the size argument in landlock_add_rule() (requested by Arnd
Bergmann).
* Remove landlock_get_features(2) (suggested by Arnd Bergmann).
* Simplify and rename copy_struct_if_any_from_user() to
copy_min_struct_from_user().
* Rename "options" to "flags" to allign with current syscalls.
* Rename some types and variables in a more consistent way.
* Fix missing type declarations in syscalls.h .
Changes since v19:
* Replace the landlock(2) syscall with 4 syscalls (one for each
command): landlock_get_features(2), landlock_create_ruleset(2),
landlock_add_rule(2) and landlock_enforce_ruleset(2) (suggested by
Arnd Bergmann).
https://lore.kernel.org/lkml/[email protected]/
* Return EOPNOTSUPP (instead of ENOPKG) when Landlock is disabled.
* Add two new fields to landlock_attr_features to fit with the new
syscalls: last_rule_type and last_target_type. This enable to easily
identify which types are supported.
* Pack landlock_attr_path_beneath struct because of the removed
ruleset_fd.
* Update documentation and fix spelling.
Changes since v18:
* Remove useless include.
* Remove LLATTR_SIZE() which was only used to shorten lines. Cf. commit
bdc48fa11e46 ("checkpatch/coding-style: deprecate 80-column warning").
Changes since v17:
* Synchronize syscall declaration.
* Fix comment.
Changes since v16:
* Add a size_attr_features field to struct landlock_attr_features for
self-introspection, and move the access_fs field to be more
consistent.
* Replace __aligned_u64 types of attribute fields with __u16, __s32,
__u32 and __u64, and check at build time that these structures does
not contain hole and that they are aligned the same way (8-bits) on
all architectures. This shrinks the size of the userspace ABI, which
may be appreciated especially for struct landlock_attr_features which
could grow a lot in the future. For instance, struct
landlock_attr_features shrinks from 72 bytes to 32 bytes. This change
also enables to remove 64-bits to 32-bits conversion checks.
* Switch syscall attribute pointer and size arguments to follow similar
syscall argument order (e.g. bpf, clone3, openat2).
* Set LANDLOCK_OPT_* types to 32-bits.
* Allow enforcement of empty ruleset, which enables deny-all policies.
* Fix documentation inconsistency.
Changes since v15:
* Do not add file descriptors referring to internal filesystems (e.g.
nsfs) in a ruleset.
* Replace is_user_mountable() with in-place clean checks.
* Replace EBADR with EBADFD in get_ruleset_from_fd() and
get_path_from_fd().
* Remove ruleset's show_fdinfo() for now.
Changes since v14:
* Remove the security_file_open() check in get_path_from_fd(): an
opened FD should not be restricted here, and even less with this hook.
As a result, it is now allowed to add a path to a ruleset even if the
access to this path is not allowed (without O_PATH). This doesn't
change the fact that enforcing a ruleset can't grant any right, only
remove some rights. The new layer levels add more consistent
restrictions.
* Check minimal landlock_attr_* size/content. This fix the case when
no data was provided and e.g., FD 0 was interpreted as ruleset_fd.
Now this leads to a returned -EINVAL.
* Fix credential double-free error case.
* Complete struct landlock_attr_size with size_attr_enforce.
* Fix undefined reference to syscall when Landlock is not selected.
* Remove f.file->f_path.mnt check (suggested by Al Viro).
* Add build-time checks.
* Move ABI checks from fs.c .
* Constify variables.
* Fix spelling.
* Add comments.
Changes since v13:
* New implementation, replacing the dependency on seccomp(2) and bpf(2).
---
include/linux/syscalls.h | 7 +
include/uapi/linux/landlock.h | 53 ++++
kernel/sys_ni.c | 5 +
security/landlock/Makefile | 2 +-
security/landlock/syscalls.c | 442 ++++++++++++++++++++++++++++++++++
5 files changed, 508 insertions(+), 1 deletion(-)
create mode 100644 security/landlock/syscalls.c
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 2839dc9a7c01..fa3971012e1c 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -69,6 +69,8 @@ struct io_uring_params;
struct clone_args;
struct open_how;
struct mount_attr;
+struct landlock_ruleset_attr;
+enum landlock_rule_type;
#include <linux/types.h>
#include <linux/aio_abi.h>
@@ -1041,6 +1043,11 @@ asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
siginfo_t __user *info,
unsigned int flags);
asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
+asmlinkage long sys_landlock_create_ruleset(const struct landlock_ruleset_attr __user *attr,
+ size_t size, __u32 flags);
+asmlinkage long sys_landlock_add_rule(int ruleset_fd, enum landlock_rule_type rule_type,
+ const void __user *rule_attr, __u32 flags);
+asmlinkage long sys_landlock_restrict_self(int ruleset_fd, __u32 flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
index b1a81b5a8b86..ba946a1e40b2 100644
--- a/include/uapi/linux/landlock.h
+++ b/include/uapi/linux/landlock.h
@@ -9,6 +9,59 @@
#ifndef _UAPI_LINUX_LANDLOCK_H
#define _UAPI_LINUX_LANDLOCK_H
+#include <linux/types.h>
+
+/**
+ * struct landlock_ruleset_attr - Ruleset definition
+ *
+ * Argument of sys_landlock_create_ruleset(). This structure can grow in
+ * future versions.
+ */
+struct landlock_ruleset_attr {
+ /**
+ * @handled_access_fs: Bitmask of actions (cf. `Filesystem flags`_)
+ * that is handled by this ruleset and should then be forbidden if no
+ * rule explicitly allow them. This is needed for backward
+ * compatibility reasons.
+ */
+ __u64 handled_access_fs;
+};
+
+/**
+ * enum landlock_rule_type - Landlock rule type
+ *
+ * Argument of sys_landlock_add_rule().
+ */
+enum landlock_rule_type {
+ /**
+ * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct
+ * landlock_path_beneath_attr .
+ */
+ LANDLOCK_RULE_PATH_BENEATH = 1,
+};
+
+/**
+ * struct landlock_path_beneath_attr - Path hierarchy definition
+ *
+ * Argument of sys_landlock_add_rule().
+ */
+struct landlock_path_beneath_attr {
+ /**
+ * @allowed_access: Bitmask of allowed actions for this file hierarchy
+ * (cf. `Filesystem flags`_).
+ */
+ __u64 allowed_access;
+ /**
+ * @parent_fd: File descriptor, open with ``O_PATH``, which identifies
+ * the parent directory of a file hierarchy, or just a file.
+ */
+ __s32 parent_fd;
+ /*
+ * This struct is packed to avoid trailing reserved members.
+ * Cf. security/landlock/syscalls.c:build_check_abi()
+ */
+} __attribute__((packed));
+
/**
* DOC: fs_access
*
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 19aa806890d5..cce430cf2ff2 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -266,6 +266,11 @@ COND_SYSCALL(request_key);
COND_SYSCALL(keyctl);
COND_SYSCALL_COMPAT(keyctl);
+/* security/landlock/syscalls.c */
+COND_SYSCALL(landlock_create_ruleset);
+COND_SYSCALL(landlock_add_rule);
+COND_SYSCALL(landlock_restrict_self);
+
/* arch/example/kernel/sys_example.c */
/* mm/fadvise.c */
diff --git a/security/landlock/Makefile b/security/landlock/Makefile
index 92e3d80ab8ed..7bbd2f413b3e 100644
--- a/security/landlock/Makefile
+++ b/security/landlock/Makefile
@@ -1,4 +1,4 @@
obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o
-landlock-y := setup.o object.o ruleset.o \
+landlock-y := setup.o syscalls.o object.o ruleset.o \
cred.o ptrace.o fs.o
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
new file mode 100644
index 000000000000..93620ad7593b
--- /dev/null
+++ b/security/landlock/syscalls.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - System call implementations and user space interfaces
+ *
+ * Copyright © 2016-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2018-2020 ANSSI
+ */
+
+#include <asm/current.h>
+#include <linux/anon_inodes.h>
+#include <linux/build_bug.h>
+#include <linux/capability.h>
+#include <linux/compiler_types.h>
+#include <linux/dcache.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/limits.h>
+#include <linux/mount.h>
+#include <linux/path.h>
+#include <linux/sched.h>
+#include <linux/security.h>
+#include <linux/stddef.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <uapi/linux/landlock.h>
+
+#include "cred.h"
+#include "fs.h"
+#include "limits.h"
+#include "ruleset.h"
+#include "setup.h"
+
+/**
+ * copy_min_struct_from_user - Safe future-proof argument copying
+ *
+ * Extend copy_struct_from_user() to check for consistent user buffer.
+ *
+ * @dst: Kernel space pointer or NULL.
+ * @ksize: Actual size of the data pointed to by @dst.
+ * @ksize_min: Minimal required size to be copied.
+ * @src: User space pointer or NULL.
+ * @usize: (Alleged) size of the data pointed to by @src.
+ */
+static __always_inline int copy_min_struct_from_user(void *const dst,
+ const size_t ksize, const size_t ksize_min,
+ const void __user *const src, const size_t usize)
+{
+ /* Checks buffer inconsistencies. */
+ BUILD_BUG_ON(!dst);
+ if (!src)
+ return -EFAULT;
+
+ /* Checks size ranges. */
+ BUILD_BUG_ON(ksize <= 0);
+ BUILD_BUG_ON(ksize < ksize_min);
+ if (usize < ksize_min)
+ return -EINVAL;
+ if (usize > PAGE_SIZE)
+ return -E2BIG;
+
+ /* Copies user buffer and fills with zeros. */
+ return copy_struct_from_user(dst, ksize, src, usize);
+}
+
+/*
+ * This function only contains arithmetic operations with constants, leading to
+ * BUILD_BUG_ON(). The related code is evaluated and checked at build time,
+ * but it is then ignored thanks to compiler optimizations.
+ */
+static void build_check_abi(void)
+{
+ struct landlock_ruleset_attr ruleset_attr;
+ struct landlock_path_beneath_attr path_beneath_attr;
+ size_t ruleset_size, path_beneath_size;
+
+ /*
+ * For each user space ABI structures, first checks that there is no
+ * hole in them, then checks that all architectures have the same
+ * struct size.
+ */
+ ruleset_size = sizeof(ruleset_attr.handled_access_fs);
+ BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size);
+ BUILD_BUG_ON(sizeof(ruleset_attr) != 8);
+
+ path_beneath_size = sizeof(path_beneath_attr.allowed_access);
+ path_beneath_size += sizeof(path_beneath_attr.parent_fd);
+ BUILD_BUG_ON(sizeof(path_beneath_attr) != path_beneath_size);
+ BUILD_BUG_ON(sizeof(path_beneath_attr) != 12);
+}
+
+/* Ruleset handling */
+
+static int fop_ruleset_release(struct inode *const inode,
+ struct file *const filp)
+{
+ struct landlock_ruleset *ruleset = filp->private_data;
+
+ landlock_put_ruleset(ruleset);
+ return 0;
+}
+
+static ssize_t fop_dummy_read(struct file *const filp, char __user *const buf,
+ const size_t size, loff_t *const ppos)
+{
+ /* Dummy handler to enable FMODE_CAN_READ. */
+ return -EINVAL;
+}
+
+static ssize_t fop_dummy_write(struct file *const filp,
+ const char __user *const buf, const size_t size,
+ loff_t *const ppos)
+{
+ /* Dummy handler to enable FMODE_CAN_WRITE. */
+ return -EINVAL;
+}
+
+/*
+ * A ruleset file descriptor enables to build a ruleset by adding (i.e.
+ * writing) rule after rule, without relying on the task's context. This
+ * reentrant design is also used in a read way to enforce the ruleset on the
+ * current task.
+ */
+static const struct file_operations ruleset_fops = {
+ .release = fop_ruleset_release,
+ .read = fop_dummy_read,
+ .write = fop_dummy_write,
+};
+
+/**
+ * sys_landlock_create_ruleset - Create a new ruleset
+ *
+ * @attr: Pointer to a &struct landlock_ruleset_attr identifying the scope of
+ * the new ruleset.
+ * @size: Size of the pointed &struct landlock_ruleset_attr (needed for
+ * backward and forward compatibility).
+ * @flags: Must be 0.
+ *
+ * This system call enables to create a new Landlock ruleset, and returns the
+ * related file descriptor on success.
+ *
+ * Possible returned errors are:
+ *
+ * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time;
+ * - EINVAL: @flags is not 0, or unknown access, or too small @size;
+ * - E2BIG or EFAULT: @attr or @size inconsistencies;
+ * - ENOMSG: empty &landlock_ruleset_attr.handled_access_fs.
+ */
+SYSCALL_DEFINE3(landlock_create_ruleset,
+ const struct landlock_ruleset_attr __user *const, attr,
+ const size_t, size, const __u32, flags)
+{
+ struct landlock_ruleset_attr ruleset_attr;
+ struct landlock_ruleset *ruleset;
+ int err, ruleset_fd;
+
+ /* Build-time checks. */
+ build_check_abi();
+
+ if (!landlock_initialized)
+ return -EOPNOTSUPP;
+
+ /* No flag for now. */
+ if (flags)
+ return -EINVAL;
+
+ /* Copies raw user space buffer. */
+ err = copy_min_struct_from_user(&ruleset_attr, sizeof(ruleset_attr),
+ offsetofend(typeof(ruleset_attr), handled_access_fs),
+ attr, size);
+ if (err)
+ return err;
+
+ /* Checks content (and 32-bits cast). */
+ if ((ruleset_attr.handled_access_fs | LANDLOCK_MASK_ACCESS_FS) !=
+ LANDLOCK_MASK_ACCESS_FS)
+ return -EINVAL;
+
+ /* Checks arguments and transforms to kernel struct. */
+ ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs);
+ if (IS_ERR(ruleset))
+ return PTR_ERR(ruleset);
+
+ /* Creates anonymous FD referring to the ruleset. */
+ ruleset_fd = anon_inode_getfd("landlock-ruleset", &ruleset_fops,
+ ruleset, O_RDWR | O_CLOEXEC);
+ if (ruleset_fd < 0)
+ landlock_put_ruleset(ruleset);
+ return ruleset_fd;
+}
+
+/*
+ * Returns an owned ruleset from a FD. It is thus needed to call
+ * landlock_put_ruleset() on the return value.
+ */
+static struct landlock_ruleset *get_ruleset_from_fd(const int fd,
+ const fmode_t mode)
+{
+ struct fd ruleset_f;
+ struct landlock_ruleset *ruleset;
+
+ ruleset_f = fdget(fd);
+ if (!ruleset_f.file)
+ return ERR_PTR(-EBADF);
+
+ /* Checks FD type and access right. */
+ if (ruleset_f.file->f_op != &ruleset_fops) {
+ ruleset = ERR_PTR(-EBADFD);
+ goto out_fdput;
+ }
+ if (!(ruleset_f.file->f_mode & mode)) {
+ ruleset = ERR_PTR(-EPERM);
+ goto out_fdput;
+ }
+ ruleset = ruleset_f.file->private_data;
+ if (WARN_ON_ONCE(ruleset->num_layers != 1)) {
+ ruleset = ERR_PTR(-EINVAL);
+ goto out_fdput;
+ }
+ landlock_get_ruleset(ruleset);
+
+out_fdput:
+ fdput(ruleset_f);
+ return ruleset;
+}
+
+/* Path handling */
+
+/*
+ * @path: Must call put_path(@path) after the call if it succeeded.
+ */
+static int get_path_from_fd(const s32 fd, struct path *const path)
+{
+ struct fd f;
+ int err = 0;
+
+ BUILD_BUG_ON(!__same_type(fd,
+ ((struct landlock_path_beneath_attr *)NULL)->parent_fd));
+
+ /* Handles O_PATH. */
+ f = fdget_raw(fd);
+ if (!f.file)
+ return -EBADF;
+ /*
+ * Forbids ruleset FDs, internal filesystems (e.g. nsfs), including
+ * pseudo filesystems that will never be mountable (e.g. sockfs,
+ * pipefs).
+ */
+ if ((f.file->f_op == &ruleset_fops) ||
+ (f.file->f_path.mnt->mnt_flags & MNT_INTERNAL) ||
+ (f.file->f_path.dentry->d_sb->s_flags & SB_NOUSER) ||
+ d_is_negative(f.file->f_path.dentry) ||
+ IS_PRIVATE(d_backing_inode(f.file->f_path.dentry))) {
+ err = -EBADFD;
+ goto out_fdput;
+ }
+ *path = f.file->f_path;
+ path_get(path);
+
+out_fdput:
+ fdput(f);
+ return err;
+}
+
+/**
+ * sys_landlock_add_rule - Add a new rule to a ruleset
+ *
+ * @ruleset_fd: File descriptor tied to the ruleset that should be extended
+ * with the new rule.
+ * @rule_type: Identify the structure type pointed to by @rule_attr (only
+ * LANDLOCK_RULE_PATH_BENEATH for now).
+ * @rule_attr: Pointer to a rule (only of type &struct
+ * landlock_path_beneath_attr for now).
+ * @flags: Must be 0.
+ *
+ * This system call enables to define a new rule and add it to an existing
+ * ruleset.
+ *
+ * Possible returned errors are:
+ *
+ * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time;
+ * - EINVAL: @flags is not 0, or inconsistent access in the rule (i.e.
+ * &landlock_path_beneath_attr.allowed_access is not a subset of the rule's
+ * accesses);
+ * - ENOMSG: Empty accesses (e.g. &landlock_path_beneath_attr.allowed_access);
+ * - EBADF: @ruleset_fd is not a file descriptor for the current thread, or a
+ * member of @rule_attr is not a file descriptor as expected;
+ * - EBADFD: @ruleset_fd is not a ruleset file descriptor, or a member of
+ * @rule_attr is not the expected file descriptor type (e.g. file open
+ * without O_PATH);
+ * - EPERM: @ruleset_fd has no write access to the underlying ruleset;
+ * - EFAULT: @rule_attr inconsistency.
+ */
+SYSCALL_DEFINE4(landlock_add_rule,
+ const int, ruleset_fd, const enum landlock_rule_type, rule_type,
+ const void __user *const, rule_attr, const __u32, flags)
+{
+ struct landlock_path_beneath_attr path_beneath_attr;
+ struct path path;
+ struct landlock_ruleset *ruleset;
+ int res, err;
+
+ if (!landlock_initialized)
+ return -EOPNOTSUPP;
+
+ /* No flag for now. */
+ if (flags)
+ return -EINVAL;
+
+ if (rule_type != LANDLOCK_RULE_PATH_BENEATH)
+ return -EINVAL;
+
+ /* Copies raw user space buffer, only one type for now. */
+ res = copy_from_user(&path_beneath_attr, rule_attr,
+ sizeof(path_beneath_attr));
+ if (res)
+ return -EFAULT;
+
+ /* Gets and checks the ruleset. */
+ ruleset = get_ruleset_from_fd(ruleset_fd, FMODE_CAN_WRITE);
+ if (IS_ERR(ruleset))
+ return PTR_ERR(ruleset);
+
+ /*
+ * Informs about useless rule: empty allowed_access (i.e. deny rules)
+ * are ignored in path walks.
+ */
+ if (!path_beneath_attr.allowed_access) {
+ err = -ENOMSG;
+ goto out_put_ruleset;
+ }
+ /*
+ * Checks that allowed_access matches the @ruleset constraints
+ * (ruleset->fs_access_masks[0] is automatically upgraded to 64-bits).
+ */
+ if ((path_beneath_attr.allowed_access | ruleset->fs_access_masks[0]) !=
+ ruleset->fs_access_masks[0]) {
+ err = -EINVAL;
+ goto out_put_ruleset;
+ }
+
+ /* Gets and checks the new rule. */
+ err = get_path_from_fd(path_beneath_attr.parent_fd, &path);
+ if (err)
+ goto out_put_ruleset;
+
+ /* Imports the new rule. */
+ err = landlock_append_fs_rule(ruleset, &path,
+ path_beneath_attr.allowed_access);
+ path_put(&path);
+
+out_put_ruleset:
+ landlock_put_ruleset(ruleset);
+ return err;
+}
+
+/* Enforcement */
+
+/**
+ * sys_landlock_restrict_self - Enforce a ruleset on the calling thread
+ *
+ * @ruleset_fd: File descriptor tied to the ruleset to merge with the target.
+ * @flags: Must be 0.
+ *
+ * This system call enables to enforce a Landlock ruleset on the current
+ * thread. Enforcing a ruleset requires that the task has CAP_SYS_ADMIN in its
+ * namespace or is running with no_new_privs. This avoids scenarios where
+ * unprivileged tasks can affect the behavior of privileged children.
+ *
+ * Possible returned errors are:
+ *
+ * - EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time;
+ * - EINVAL: @flags is not 0.
+ * - EBADF: @ruleset_fd is not a file descriptor for the current thread;
+ * - EBADFD: @ruleset_fd is not a ruleset file descriptor;
+ * - EPERM: @ruleset_fd has no read access to the underlying ruleset, or the
+ * current thread is not running with no_new_privs, or it doesn't have
+ * CAP_SYS_ADMIN in its namespace.
+ * - E2BIG: The maximum number of stacked rulesets is reached for the current
+ * thread.
+ */
+SYSCALL_DEFINE2(landlock_restrict_self,
+ const int, ruleset_fd, const __u32, flags)
+{
+ struct landlock_ruleset *new_dom, *ruleset;
+ struct cred *new_cred;
+ struct landlock_cred_security *new_llcred;
+ int err;
+
+ if (!landlock_initialized)
+ return -EOPNOTSUPP;
+
+ /* No flag for now. */
+ if (flags)
+ return -EINVAL;
+
+ /*
+ * Similar checks as for seccomp(2), except that an -EPERM may be
+ * returned.
+ */
+ if (!task_no_new_privs(current) &&
+ !ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* Gets and checks the ruleset. */
+ ruleset = get_ruleset_from_fd(ruleset_fd, FMODE_CAN_READ);
+ if (IS_ERR(ruleset))
+ return PTR_ERR(ruleset);
+
+ /* Prepares new credentials. */
+ new_cred = prepare_creds();
+ if (!new_cred) {
+ err = -ENOMEM;
+ goto out_put_ruleset;
+ }
+ new_llcred = landlock_cred(new_cred);
+
+ /*
+ * There is no possible race condition while copying and manipulating
+ * the current credentials because they are dedicated per thread.
+ */
+ new_dom = landlock_merge_ruleset(new_llcred->domain, ruleset);
+ if (IS_ERR(new_dom)) {
+ err = PTR_ERR(new_dom);
+ goto out_put_creds;
+ }
+
+ /* Replaces the old (prepared) domain. */
+ landlock_put_ruleset(new_llcred->domain);
+ new_llcred->domain = new_dom;
+
+ landlock_put_ruleset(ruleset);
+ return commit_creds(new_cred);
+
+out_put_creds:
+ abort_creds(new_cred);
+
+out_put_ruleset:
+ landlock_put_ruleset(ruleset);
+ return err;
+}
--
2.30.2
From: Casey Schaufler <[email protected]>
Move management of the superblock->sb_security blob out of the
individual security modules and into the security infrastructure.
Instead of allocating the blobs from within the modules, the modules
tell the infrastructure how much space is required, and the space is
allocated there.
Cc: John Johansen <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Stephen Smalley <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Add Acked-by Serge Hallyn.
Changes since v26:
* Rebase on commit b159e86b5a2a ("selinux: drop super_block backpointer
from superblock_security_struct"). No change in the patch itself,
only a trivial conflict because of an updated nearby line in
selinux_set_mnt_opts() variable declarations.
Changes since v20:
* Remove all Reviewed-by except Stephen Smalley:
https://lore.kernel.org/lkml/CAEjxPJ7ARJO57MBW66=xsBzMMRb=9uLgqocK5eskHCaiVMx7Vw@mail.gmail.com/
* Cosmetic fix in the commit message.
Changes since v17:
* Rebase the original LSM stacking patch from v5.3 to v5.7: I fixed some
diff conflicts caused by code moves and function renames in
selinux/include/objsec.h and selinux/hooks.c . I checked that it
builds but I didn't test the changes for SELinux nor SMACK.
https://lore.kernel.org/r/[email protected]
---
include/linux/lsm_hooks.h | 1 +
security/security.c | 46 ++++++++++++++++++++----
security/selinux/hooks.c | 58 ++++++++++++-------------------
security/selinux/include/objsec.h | 6 ++++
security/selinux/ss/services.c | 3 +-
security/smack/smack.h | 6 ++++
security/smack/smack_lsm.c | 35 +++++--------------
7 files changed, 85 insertions(+), 70 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index fb7f3193753d..75715998a95f 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1573,6 +1573,7 @@ struct lsm_blob_sizes {
int lbs_cred;
int lbs_file;
int lbs_inode;
+ int lbs_superblock;
int lbs_ipc;
int lbs_msg_msg;
int lbs_task;
diff --git a/security/security.c b/security/security.c
index 5ac96b16f8fa..e9c29480eb18 100644
--- a/security/security.c
+++ b/security/security.c
@@ -203,6 +203,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
+ lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
}
@@ -333,12 +334,13 @@ static void __init ordered_lsm_init(void)
for (lsm = ordered_lsms; *lsm; lsm++)
prepare_lsm(*lsm);
- init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
- init_debug("file blob size = %d\n", blob_sizes.lbs_file);
- init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
- init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
- init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
- init_debug("task blob size = %d\n", blob_sizes.lbs_task);
+ init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
+ init_debug("file blob size = %d\n", blob_sizes.lbs_file);
+ init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
+ init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
+ init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
+ init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
+ init_debug("task blob size = %d\n", blob_sizes.lbs_task);
/*
* Create any kmem_caches needed for blobs
@@ -670,6 +672,27 @@ static void __init lsm_early_task(struct task_struct *task)
panic("%s: Early task alloc failed.\n", __func__);
}
+/**
+ * lsm_superblock_alloc - allocate a composite superblock blob
+ * @sb: the superblock that needs a blob
+ *
+ * Allocate the superblock blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_superblock_alloc(struct super_block *sb)
+{
+ if (blob_sizes.lbs_superblock == 0) {
+ sb->s_security = NULL;
+ return 0;
+ }
+
+ sb->s_security = kzalloc(blob_sizes.lbs_superblock, GFP_KERNEL);
+ if (sb->s_security == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
/*
* The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
* can be accessed with:
@@ -867,12 +890,21 @@ int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *
int security_sb_alloc(struct super_block *sb)
{
- return call_int_hook(sb_alloc_security, 0, sb);
+ int rc = lsm_superblock_alloc(sb);
+
+ if (unlikely(rc))
+ return rc;
+ rc = call_int_hook(sb_alloc_security, 0, sb);
+ if (unlikely(rc))
+ security_sb_free(sb);
+ return rc;
}
void security_sb_free(struct super_block *sb)
{
call_void_hook(sb_free_security, sb);
+ kfree(sb->s_security);
+ sb->s_security = NULL;
}
void security_free_mnt_opts(void **mnt_opts)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ddd097790d47..2ed9c995263a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -322,7 +322,7 @@ static void inode_free_security(struct inode *inode)
if (!isec)
return;
- sbsec = inode->i_sb->s_security;
+ sbsec = selinux_superblock(inode->i_sb);
/*
* As not all inode security structures are in a list, we check for
* empty list outside of the lock to make sure that we won't waste
@@ -340,13 +340,6 @@ static void inode_free_security(struct inode *inode)
}
}
-static void superblock_free_security(struct super_block *sb)
-{
- struct superblock_security_struct *sbsec = sb->s_security;
- sb->s_security = NULL;
- kfree(sbsec);
-}
-
struct selinux_mnt_opts {
const char *fscontext, *context, *rootcontext, *defcontext;
};
@@ -458,7 +451,7 @@ static int selinux_is_genfs_special_handling(struct super_block *sb)
static int selinux_is_sblabel_mnt(struct super_block *sb)
{
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
/*
* IMPORTANT: Double-check logic in this function when adding a new
@@ -535,7 +528,7 @@ static int sb_check_xattr_support(struct super_block *sb)
static int sb_finish_set_opts(struct super_block *sb)
{
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
struct dentry *root = sb->s_root;
struct inode *root_inode = d_backing_inode(root);
int rc = 0;
@@ -626,7 +619,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
unsigned long *set_kern_flags)
{
const struct cred *cred = current_cred();
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
struct dentry *root = sb->s_root;
struct selinux_mnt_opts *opts = mnt_opts;
struct inode_security_struct *root_isec;
@@ -863,8 +856,8 @@ static int selinux_set_mnt_opts(struct super_block *sb,
static int selinux_cmp_sb_context(const struct super_block *oldsb,
const struct super_block *newsb)
{
- struct superblock_security_struct *old = oldsb->s_security;
- struct superblock_security_struct *new = newsb->s_security;
+ struct superblock_security_struct *old = selinux_superblock(oldsb);
+ struct superblock_security_struct *new = selinux_superblock(newsb);
char oldflags = old->flags & SE_MNTMASK;
char newflags = new->flags & SE_MNTMASK;
@@ -896,8 +889,9 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
unsigned long *set_kern_flags)
{
int rc = 0;
- const struct superblock_security_struct *oldsbsec = oldsb->s_security;
- struct superblock_security_struct *newsbsec = newsb->s_security;
+ const struct superblock_security_struct *oldsbsec =
+ selinux_superblock(oldsb);
+ struct superblock_security_struct *newsbsec = selinux_superblock(newsb);
int set_fscontext = (oldsbsec->flags & FSCONTEXT_MNT);
int set_context = (oldsbsec->flags & CONTEXT_MNT);
@@ -1076,7 +1070,7 @@ static int show_sid(struct seq_file *m, u32 sid)
static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
{
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
int rc;
if (!(sbsec->flags & SE_SBINITIALIZED))
@@ -1427,7 +1421,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
if (isec->sclass == SECCLASS_FILE)
isec->sclass = inode_mode_to_security_class(inode->i_mode);
- sbsec = inode->i_sb->s_security;
+ sbsec = selinux_superblock(inode->i_sb);
if (!(sbsec->flags & SE_SBINITIALIZED)) {
/* Defer initialization until selinux_complete_init,
after the initial policy is loaded and the security
@@ -1778,7 +1772,8 @@ selinux_determine_inode_label(const struct task_security_struct *tsec,
const struct qstr *name, u16 tclass,
u32 *_new_isid)
{
- const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
+ const struct superblock_security_struct *sbsec =
+ selinux_superblock(dir->i_sb);
if ((sbsec->flags & SE_SBINITIALIZED) &&
(sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
@@ -1809,7 +1804,7 @@ static int may_create(struct inode *dir,
int rc;
dsec = inode_security(dir);
- sbsec = dir->i_sb->s_security;
+ sbsec = selinux_superblock(dir->i_sb);
sid = tsec->sid;
@@ -1958,7 +1953,7 @@ static int superblock_has_perm(const struct cred *cred,
struct superblock_security_struct *sbsec;
u32 sid = cred_sid(cred);
- sbsec = sb->s_security;
+ sbsec = selinux_superblock(sb);
return avc_has_perm(&selinux_state,
sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
}
@@ -2587,11 +2582,7 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
static int selinux_sb_alloc_security(struct super_block *sb)
{
- struct superblock_security_struct *sbsec;
-
- sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
- if (!sbsec)
- return -ENOMEM;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
mutex_init(&sbsec->lock);
INIT_LIST_HEAD(&sbsec->isec_head);
@@ -2599,16 +2590,10 @@ static int selinux_sb_alloc_security(struct super_block *sb)
sbsec->sid = SECINITSID_UNLABELED;
sbsec->def_sid = SECINITSID_FILE;
sbsec->mntpoint_sid = SECINITSID_UNLABELED;
- sb->s_security = sbsec;
return 0;
}
-static void selinux_sb_free_security(struct super_block *sb)
-{
- superblock_free_security(sb);
-}
-
static inline int opt_len(const char *s)
{
bool open_quote = false;
@@ -2687,7 +2672,7 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
{
struct selinux_mnt_opts *opts = mnt_opts;
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
u32 sid;
int rc;
@@ -2925,7 +2910,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
int rc;
char *context;
- sbsec = dir->i_sb->s_security;
+ sbsec = selinux_superblock(dir->i_sb);
newsid = tsec->create_sid;
@@ -3227,7 +3212,7 @@ static int selinux_inode_setxattr(struct user_namespace *mnt_userns,
if (!selinux_initialized(&selinux_state))
return (inode_owner_or_capable(mnt_userns, inode) ? 0 : -EPERM);
- sbsec = inode->i_sb->s_security;
+ sbsec = selinux_superblock(inode->i_sb);
if (!(sbsec->flags & SBLABEL_MNT))
return -EOPNOTSUPP;
@@ -3472,13 +3457,14 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
struct inode_security_struct *isec = inode_security_novalidate(inode);
- struct superblock_security_struct *sbsec = inode->i_sb->s_security;
+ struct superblock_security_struct *sbsec;
u32 newsid;
int rc;
if (strcmp(name, XATTR_SELINUX_SUFFIX))
return -EOPNOTSUPP;
+ sbsec = selinux_superblock(inode->i_sb);
if (!(sbsec->flags & SBLABEL_MNT))
return -EOPNOTSUPP;
@@ -6975,6 +6961,7 @@ struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
.lbs_inode = sizeof(struct inode_security_struct),
.lbs_ipc = sizeof(struct ipc_security_struct),
.lbs_msg_msg = sizeof(struct msg_security_struct),
+ .lbs_superblock = sizeof(struct superblock_security_struct),
};
#ifdef CONFIG_PERF_EVENTS
@@ -7075,7 +7062,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds),
LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
- LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_free_mnt_opts, selinux_free_mnt_opts),
LSM_HOOK_INIT(sb_remount, selinux_sb_remount),
LSM_HOOK_INIT(sb_kern_mount, selinux_sb_kern_mount),
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index ca4d7ab6a835..2953132408bf 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -188,4 +188,10 @@ static inline u32 current_sid(void)
return tsec->sid;
}
+static inline struct superblock_security_struct *selinux_superblock(
+ const struct super_block *superblock)
+{
+ return superblock->s_security + selinux_blob_sizes.lbs_superblock;
+}
+
#endif /* _SELINUX_OBJSEC_H_ */
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 3438d0130378..9cea2e6c809f 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -47,6 +47,7 @@
#include <linux/sched.h>
#include <linux/audit.h>
#include <linux/vmalloc.h>
+#include <linux/lsm_hooks.h>
#include <net/netlabel.h>
#include "flask.h"
@@ -2875,7 +2876,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
struct sidtab *sidtab;
int rc = 0;
struct ocontext *c;
- struct superblock_security_struct *sbsec = sb->s_security;
+ struct superblock_security_struct *sbsec = selinux_superblock(sb);
const char *fstype = sb->s_type->name;
if (!selinux_initialized(state)) {
diff --git a/security/smack/smack.h b/security/smack/smack.h
index a9768b12716b..7077b18c79ec 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -357,6 +357,12 @@ static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
return ipc->security + smack_blob_sizes.lbs_ipc;
}
+static inline struct superblock_smack *smack_superblock(
+ const struct super_block *superblock)
+{
+ return superblock->s_security + smack_blob_sizes.lbs_superblock;
+}
+
/*
* Is the directory transmuting?
*/
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 12a45e61c1a5..ee3e29603c9c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -535,12 +535,7 @@ static int smack_syslog(int typefrom_file)
*/
static int smack_sb_alloc_security(struct super_block *sb)
{
- struct superblock_smack *sbsp;
-
- sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
-
- if (sbsp == NULL)
- return -ENOMEM;
+ struct superblock_smack *sbsp = smack_superblock(sb);
sbsp->smk_root = &smack_known_floor;
sbsp->smk_default = &smack_known_floor;
@@ -549,22 +544,10 @@ static int smack_sb_alloc_security(struct super_block *sb)
/*
* SMK_SB_INITIALIZED will be zero from kzalloc.
*/
- sb->s_security = sbsp;
return 0;
}
-/**
- * smack_sb_free_security - free a superblock blob
- * @sb: the superblock getting the blob
- *
- */
-static void smack_sb_free_security(struct super_block *sb)
-{
- kfree(sb->s_security);
- sb->s_security = NULL;
-}
-
struct smack_mnt_opts {
const char *fsdefault, *fsfloor, *fshat, *fsroot, *fstransmute;
};
@@ -772,7 +755,7 @@ static int smack_set_mnt_opts(struct super_block *sb,
{
struct dentry *root = sb->s_root;
struct inode *inode = d_backing_inode(root);
- struct superblock_smack *sp = sb->s_security;
+ struct superblock_smack *sp = smack_superblock(sb);
struct inode_smack *isp;
struct smack_known *skp;
struct smack_mnt_opts *opts = mnt_opts;
@@ -871,7 +854,7 @@ static int smack_set_mnt_opts(struct super_block *sb,
*/
static int smack_sb_statfs(struct dentry *dentry)
{
- struct superblock_smack *sbp = dentry->d_sb->s_security;
+ struct superblock_smack *sbp = smack_superblock(dentry->d_sb);
int rc;
struct smk_audit_info ad;
@@ -905,7 +888,7 @@ static int smack_bprm_creds_for_exec(struct linux_binprm *bprm)
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
- sbsp = inode->i_sb->s_security;
+ sbsp = smack_superblock(inode->i_sb);
if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
isp->smk_task != sbsp->smk_root)
return 0;
@@ -1157,7 +1140,7 @@ static int smack_inode_rename(struct inode *old_inode,
*/
static int smack_inode_permission(struct inode *inode, int mask)
{
- struct superblock_smack *sbsp = inode->i_sb->s_security;
+ struct superblock_smack *sbsp = smack_superblock(inode->i_sb);
struct smk_audit_info ad;
int no_block = mask & MAY_NOT_BLOCK;
int rc;
@@ -1400,7 +1383,7 @@ static int smack_inode_removexattr(struct user_namespace *mnt_userns,
*/
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
struct super_block *sbp = dentry->d_sb;
- struct superblock_smack *sbsp = sbp->s_security;
+ struct superblock_smack *sbsp = smack_superblock(sbp);
isp->smk_inode = sbsp->smk_default;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
@@ -1670,7 +1653,7 @@ static int smack_mmap_file(struct file *file,
isp = smack_inode(file_inode(file));
if (isp->smk_mmap == NULL)
return 0;
- sbsp = file_inode(file)->i_sb->s_security;
+ sbsp = smack_superblock(file_inode(file)->i_sb);
if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
isp->smk_mmap != sbsp->smk_root)
return -EACCES;
@@ -3285,7 +3268,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
return;
sbp = inode->i_sb;
- sbsp = sbp->s_security;
+ sbsp = smack_superblock(sbp);
/*
* We're going to use the superblock default label
* if there's no label on the file.
@@ -4700,6 +4683,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
.lbs_inode = sizeof(struct inode_smack),
.lbs_ipc = sizeof(struct smack_known *),
.lbs_msg_msg = sizeof(struct smack_known *),
+ .lbs_superblock = sizeof(struct superblock_smack),
};
static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
@@ -4711,7 +4695,6 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),
LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
- LSM_HOOK_INIT(sb_free_security, smack_sb_free_security),
LSM_HOOK_INIT(sb_free_mnt_opts, smack_free_mnt_opts),
LSM_HOOK_INIT(sb_eat_lsm_opts, smack_sb_eat_lsm_opts),
LSM_HOOK_INIT(sb_statfs, smack_sb_statfs),
--
2.30.2
From: Mickaël Salaün <[email protected]>
The sb_delete security hook is called when shutting down a superblock,
which may be useful to release kernel objects tied to the superblock's
lifetime (e.g. inodes).
This new hook is needed by Landlock to release (ephemerally) tagged
struct inodes. This comes from the unprivileged nature of Landlock
described in the next commit.
Cc: Al Viro <[email protected]>
Cc: James Morris <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Extend hook description (suggested by Serge Hallyn).
* Add Acked-by Serge Hallyn.
Changes since v22:
* Add Reviewed-by Jann Horn.
Changes since v17:
* Initial patch to replace the direct call to landlock_release_inodes()
(requested by James Morris).
https://lore.kernel.org/lkml/[email protected]/
---
fs/super.c | 1 +
include/linux/lsm_hook_defs.h | 1 +
include/linux/lsm_hooks.h | 3 +++
include/linux/security.h | 4 ++++
security/security.c | 5 +++++
5 files changed, 14 insertions(+)
diff --git a/fs/super.c b/fs/super.c
index 8c1baca35c16..11b7e7213fd1 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -454,6 +454,7 @@ void generic_shutdown_super(struct super_block *sb)
evict_inodes(sb);
/* only nonzero refcount inodes can have marks */
fsnotify_sb_delete(sb);
+ security_sb_delete(sb);
if (sb->s_dio_done_wq) {
destroy_workqueue(sb->s_dio_done_wq);
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 477a597db013..e8adadbf9581 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -59,6 +59,7 @@ LSM_HOOK(int, 0, fs_context_dup, struct fs_context *fc,
LSM_HOOK(int, -ENOPARAM, fs_context_parse_param, struct fs_context *fc,
struct fs_parameter *param)
LSM_HOOK(int, 0, sb_alloc_security, struct super_block *sb)
+LSM_HOOK(void, LSM_RET_VOID, sb_delete, struct super_block *sb)
LSM_HOOK(void, LSM_RET_VOID, sb_free_security, struct super_block *sb)
LSM_HOOK(void, LSM_RET_VOID, sb_free_mnt_opts, void *mnt_opts)
LSM_HOOK(int, 0, sb_eat_lsm_opts, char *orig, void **mnt_opts)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 75715998a95f..cc2eaaaec0e4 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -108,6 +108,9 @@
* allocated.
* @sb contains the super_block structure to be modified.
* Return 0 if operation was successful.
+ * @sb_delete:
+ * Release objects tied to a superblock (e.g. inodes).
+ * @sb contains the super_block structure being released.
* @sb_free_security:
* Deallocate and clear the sb->s_security field.
* @sb contains the super_block structure to be modified.
diff --git a/include/linux/security.h b/include/linux/security.h
index 8aeebd6646dc..90298baa4551 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -291,6 +291,7 @@ void security_bprm_committed_creds(struct linux_binprm *bprm);
int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc);
int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param);
int security_sb_alloc(struct super_block *sb);
+void security_sb_delete(struct super_block *sb);
void security_sb_free(struct super_block *sb);
void security_free_mnt_opts(void **mnt_opts);
int security_sb_eat_lsm_opts(char *options, void **mnt_opts);
@@ -631,6 +632,9 @@ static inline int security_sb_alloc(struct super_block *sb)
return 0;
}
+static inline void security_sb_delete(struct super_block *sb)
+{ }
+
static inline void security_sb_free(struct super_block *sb)
{ }
diff --git a/security/security.c b/security/security.c
index e9c29480eb18..bb666f992497 100644
--- a/security/security.c
+++ b/security/security.c
@@ -900,6 +900,11 @@ int security_sb_alloc(struct super_block *sb)
return rc;
}
+void security_sb_delete(struct super_block *sb)
+{
+ call_void_hook(sb_delete, sb);
+}
+
void security_sb_free(struct super_block *sb)
{
call_void_hook(sb_free_security, sb);
--
2.30.2
From: Mickaël Salaün <[email protected]>
Using ptrace(2) and related debug features on a target process can lead
to a privilege escalation. Indeed, ptrace(2) can be used by an attacker
to impersonate another task and to remain undetected while performing
malicious activities. Thanks to ptrace_may_access(), various part of
the kernel can check if a tracer is more privileged than a tracee.
A landlocked process has fewer privileges than a non-landlocked process
and must then be subject to additional restrictions when manipulating
processes. To be allowed to use ptrace(2) and related syscalls on a
target process, a landlocked process must have a subset of the target
process's rules (i.e. the tracee must be in a sub-domain of the tracer).
Cc: James Morris <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Add Reviewed-by Kees Cook.
Changes since v28:
* Add Acked-by Serge Hallyn.
Changes since v25:
* Rename function to landlock_add_ptrace_hooks().
Changes since v22:
* Add Reviewed-by Jann Horn.
Changes since v21:
* Fix copyright dates.
Changes since v14:
* Constify variables.
Changes since v13:
* Make the ptrace restriction mandatory, like in the v10.
* Remove the eBPF dependency.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
security/landlock/Makefile | 2 +-
security/landlock/ptrace.c | 120 +++++++++++++++++++++++++++++++++++++
security/landlock/ptrace.h | 14 +++++
security/landlock/setup.c | 2 +
4 files changed, 137 insertions(+), 1 deletion(-)
create mode 100644 security/landlock/ptrace.c
create mode 100644 security/landlock/ptrace.h
diff --git a/security/landlock/Makefile b/security/landlock/Makefile
index 041ea242e627..f1d1eb72fa76 100644
--- a/security/landlock/Makefile
+++ b/security/landlock/Makefile
@@ -1,4 +1,4 @@
obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o
landlock-y := setup.o object.o ruleset.o \
- cred.o
+ cred.o ptrace.o
diff --git a/security/landlock/ptrace.c b/security/landlock/ptrace.c
new file mode 100644
index 000000000000..f55b82446de2
--- /dev/null
+++ b/security/landlock/ptrace.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock LSM - Ptrace hooks
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2019-2020 ANSSI
+ */
+
+#include <asm/current.h>
+#include <linux/cred.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/lsm_hooks.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+
+#include "common.h"
+#include "cred.h"
+#include "ptrace.h"
+#include "ruleset.h"
+#include "setup.h"
+
+/**
+ * domain_scope_le - Checks domain ordering for scoped ptrace
+ *
+ * @parent: Parent domain.
+ * @child: Potential child of @parent.
+ *
+ * Checks if the @parent domain is less or equal to (i.e. an ancestor, which
+ * means a subset of) the @child domain.
+ */
+static bool domain_scope_le(const struct landlock_ruleset *const parent,
+ const struct landlock_ruleset *const child)
+{
+ const struct landlock_hierarchy *walker;
+
+ if (!parent)
+ return true;
+ if (!child)
+ return false;
+ for (walker = child->hierarchy; walker; walker = walker->parent) {
+ if (walker == parent->hierarchy)
+ /* @parent is in the scoped hierarchy of @child. */
+ return true;
+ }
+ /* There is no relationship between @parent and @child. */
+ return false;
+}
+
+static bool task_is_scoped(const struct task_struct *const parent,
+ const struct task_struct *const child)
+{
+ bool is_scoped;
+ const struct landlock_ruleset *dom_parent, *dom_child;
+
+ rcu_read_lock();
+ dom_parent = landlock_get_task_domain(parent);
+ dom_child = landlock_get_task_domain(child);
+ is_scoped = domain_scope_le(dom_parent, dom_child);
+ rcu_read_unlock();
+ return is_scoped;
+}
+
+static int task_ptrace(const struct task_struct *const parent,
+ const struct task_struct *const child)
+{
+ /* Quick return for non-landlocked tasks. */
+ if (!landlocked(parent))
+ return 0;
+ if (task_is_scoped(parent, child))
+ return 0;
+ return -EPERM;
+}
+
+/**
+ * hook_ptrace_access_check - Determines whether the current process may access
+ * another
+ *
+ * @child: Process to be accessed.
+ * @mode: Mode of attachment.
+ *
+ * If the current task has Landlock rules, then the child must have at least
+ * the same rules. Else denied.
+ *
+ * Determines whether a process may access another, returning 0 if permission
+ * granted, -errno if denied.
+ */
+static int hook_ptrace_access_check(struct task_struct *const child,
+ const unsigned int mode)
+{
+ return task_ptrace(current, child);
+}
+
+/**
+ * hook_ptrace_traceme - Determines whether another process may trace the
+ * current one
+ *
+ * @parent: Task proposed to be the tracer.
+ *
+ * If the parent has Landlock rules, then the current task must have the same
+ * or more rules. Else denied.
+ *
+ * Determines whether the nominated task is permitted to trace the current
+ * process, returning 0 if permission is granted, -errno if denied.
+ */
+static int hook_ptrace_traceme(struct task_struct *const parent)
+{
+ return task_ptrace(parent, current);
+}
+
+static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
+ LSM_HOOK_INIT(ptrace_access_check, hook_ptrace_access_check),
+ LSM_HOOK_INIT(ptrace_traceme, hook_ptrace_traceme),
+};
+
+__init void landlock_add_ptrace_hooks(void)
+{
+ security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
+ LANDLOCK_NAME);
+}
diff --git a/security/landlock/ptrace.h b/security/landlock/ptrace.h
new file mode 100644
index 000000000000..265b220ae3bf
--- /dev/null
+++ b/security/landlock/ptrace.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Landlock LSM - Ptrace hooks
+ *
+ * Copyright © 2017-2019 Mickaël Salaün <[email protected]>
+ * Copyright © 2019 ANSSI
+ */
+
+#ifndef _SECURITY_LANDLOCK_PTRACE_H
+#define _SECURITY_LANDLOCK_PTRACE_H
+
+__init void landlock_add_ptrace_hooks(void);
+
+#endif /* _SECURITY_LANDLOCK_PTRACE_H */
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
index 8661112fb238..a5d6ef334991 100644
--- a/security/landlock/setup.c
+++ b/security/landlock/setup.c
@@ -11,6 +11,7 @@
#include "common.h"
#include "cred.h"
+#include "ptrace.h"
#include "setup.h"
struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
@@ -20,6 +21,7 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
static int __init landlock_init(void)
{
landlock_add_cred_hooks();
+ landlock_add_ptrace_hooks();
pr_info("Up and running.\n");
return 0;
}
--
2.30.2
From: Mickaël Salaün <[email protected]>
Wire up the following system calls for all architectures:
* landlock_create_ruleset(2)
* landlock_add_rule(2)
* landlock_restrict_self(2)
Cc: Arnd Bergmann <[email protected]>
Cc: James Morris <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v30:
* Increase syscall numbers to leave space for quotactl_path(2):
synchronize with Landlock syscalls in -next.
Changes since v29:
* Rebase on v5.12-rc3 and fix trivial conflict with mount_setattr(2).
* Synchronize syscall numbers with -next, which are the same as for
v5.12-rc3.
Changes since v27:
* Rename landlock_enforce_ruleset_self(2) to landlock_restrict_self(2).
* Cosmetic fix: align TBL enries.
Changes since v26:
* Rename landlock_enforce_ruleset_current(2) to
landlock_enforce_ruleset_self(2).
Changes since v25:
* Rebase and leave space for the new epoll_pwait2(2) and memfd_secret(2)
from -next.
Changes since v21:
* Rebase and leave space for watch_mount(2) from -next.
Changes since v20:
* Remove landlock_get_features(2).
* Decrease syscall numbers to stick to process_madvise(2) in -next.
* Rename landlock_enforce_ruleset(2) to
landlock_enforce_ruleset_current(2).
Changes since v19:
* Increase syscall numbers by 4 to leave space for new ones (in
linux-next): watch_mount(2), watch_sb(2), fsinfo(2) and
process_madvise(2) (requested by Arnd Bergmann).
* Replace the previous multiplexor landlock(2) with 4 syscalls:
landlock_get_features(2), landlock_create_ruleset(2),
landlock_add_rule(2) and landlock_enforce_ruleset(2).
Changes since v18:
* Increase the syscall number because of the new faccessat2(2).
Changes since v14:
* Add all architectures.
Changes since v13:
* New implementation.
---
arch/alpha/kernel/syscalls/syscall.tbl | 3 +++
arch/arm/tools/syscall.tbl | 3 +++
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 6 ++++++
arch/ia64/kernel/syscalls/syscall.tbl | 3 +++
arch/m68k/kernel/syscalls/syscall.tbl | 3 +++
arch/microblaze/kernel/syscalls/syscall.tbl | 3 +++
arch/mips/kernel/syscalls/syscall_n32.tbl | 3 +++
arch/mips/kernel/syscalls/syscall_n64.tbl | 3 +++
arch/mips/kernel/syscalls/syscall_o32.tbl | 3 +++
arch/parisc/kernel/syscalls/syscall.tbl | 3 +++
arch/powerpc/kernel/syscalls/syscall.tbl | 3 +++
arch/s390/kernel/syscalls/syscall.tbl | 3 +++
arch/sh/kernel/syscalls/syscall.tbl | 3 +++
arch/sparc/kernel/syscalls/syscall.tbl | 3 +++
arch/x86/entry/syscalls/syscall_32.tbl | 3 +++
arch/x86/entry/syscalls/syscall_64.tbl | 3 +++
arch/xtensa/kernel/syscalls/syscall.tbl | 3 +++
include/uapi/asm-generic/unistd.h | 8 +++++++-
19 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 02f0244e005c..4240f21b10b3 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -482,3 +482,6 @@
550 common process_madvise sys_process_madvise
551 common epoll_pwait2 sys_epoll_pwait2
552 common mount_setattr sys_mount_setattr
+554 common landlock_create_ruleset sys_landlock_create_ruleset
+555 common landlock_add_rule sys_landlock_add_rule
+556 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index dcc1191291a2..161423a5d773 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -456,3 +456,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 949788f5ba40..727bfc3be99b 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,7 +38,7 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 443
+#define __NR_compat_syscalls 447
#endif
#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 3d874f624056..fdfe06bae3fc 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -893,6 +893,12 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
__SYSCALL(__NR_epoll_pwait2, compat_sys_epoll_pwait2)
#define __NR_mount_setattr 442
__SYSCALL(__NR_mount_setattr, sys_mount_setattr)
+#define __NR_landlock_create_ruleset 444
+__SYSCALL(__NR_landlock_create_ruleset, sys_landlock_create_ruleset)
+#define __NR_landlock_add_rule 445
+__SYSCALL(__NR_landlock_add_rule, sys_landlock_add_rule)
+#define __NR_landlock_restrict_self 446
+__SYSCALL(__NR_landlock_restrict_self, sys_landlock_restrict_self)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index d89231166e19..48dbbc95a01f 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -363,3 +363,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 72bde6707dd3..595108bbbe42 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -442,3 +442,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index d603a5ec9338..db23d65871f9 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -448,3 +448,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 8fd8c1790941..5028839225fa 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -381,3 +381,6 @@
440 n32 process_madvise sys_process_madvise
441 n32 epoll_pwait2 compat_sys_epoll_pwait2
442 n32 mount_setattr sys_mount_setattr
+444 n32 landlock_create_ruleset sys_landlock_create_ruleset
+445 n32 landlock_add_rule sys_landlock_add_rule
+446 n32 landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 169f21438065..ec9c68b75e23 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -357,3 +357,6 @@
440 n64 process_madvise sys_process_madvise
441 n64 epoll_pwait2 sys_epoll_pwait2
442 n64 mount_setattr sys_mount_setattr
+444 n64 landlock_create_ruleset sys_landlock_create_ruleset
+445 n64 landlock_add_rule sys_landlock_add_rule
+446 n64 landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 090d29ca80ff..24afd33e3e49 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -430,3 +430,6 @@
440 o32 process_madvise sys_process_madvise
441 o32 epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 o32 mount_setattr sys_mount_setattr
+444 o32 landlock_create_ruleset sys_landlock_create_ruleset
+445 o32 landlock_add_rule sys_landlock_add_rule
+446 o32 landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 271a92519683..8ddd0b82d767 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -440,3 +440,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 0b2480cf3e47..02150894b1cf 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -522,3 +522,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 3abef2144dac..331663efd3e7 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -445,3 +445,6 @@
440 common process_madvise sys_process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index d08eebad6b7f..6ada711f4b72 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -445,3 +445,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 84403a99039c..1dbe3239a638 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -488,3 +488,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index a1c9f496fca6..782c310de1da 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -447,3 +447,6 @@
440 i386 process_madvise sys_process_madvise
441 i386 epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
442 i386 mount_setattr sys_mount_setattr
+444 i386 landlock_create_ruleset sys_landlock_create_ruleset
+445 i386 landlock_add_rule sys_landlock_add_rule
+446 i386 landlock_restrict_self sys_landlock_restrict_self
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 7bf01cbe582f..8604ee4bfff9 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -364,6 +364,9 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 365a9b849224..2fad056a32e8 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -413,3 +413,6 @@
440 common process_madvise sys_process_madvise
441 common epoll_pwait2 sys_epoll_pwait2
442 common mount_setattr sys_mount_setattr
+444 common landlock_create_ruleset sys_landlock_create_ruleset
+445 common landlock_add_rule sys_landlock_add_rule
+446 common landlock_restrict_self sys_landlock_restrict_self
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index ce58cff99b66..300608b05226 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -863,9 +863,15 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
__SC_COMP(__NR_epoll_pwait2, sys_epoll_pwait2, compat_sys_epoll_pwait2)
#define __NR_mount_setattr 442
__SYSCALL(__NR_mount_setattr, sys_mount_setattr)
+#define __NR_landlock_create_ruleset 444
+__SYSCALL(__NR_landlock_create_ruleset, sys_landlock_create_ruleset)
+#define __NR_landlock_add_rule 445
+__SYSCALL(__NR_landlock_add_rule, sys_landlock_add_rule)
+#define __NR_landlock_restrict_self 446
+__SYSCALL(__NR_landlock_restrict_self, sys_landlock_restrict_self)
#undef __NR_syscalls
-#define __NR_syscalls 443
+#define __NR_syscalls 447
/*
* 32 bit systems traditionally used different
--
2.30.2
From: Mickaël Salaün <[email protected]>
Add a first document describing userspace API: how to define and enforce
a Landlock security policy. This is explained with a simple example.
The Landlock system calls are described with their expected behavior and
current limitations.
Another document is dedicated to kernel developers, describing guiding
principles and some important kernel structures.
This documentation can be built with the Sphinx framework.
Cc: James Morris <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Vincent Dagonneau <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v31:
* Use "filesystem topology".
* Add Reviewed-by Kees Cook.
Changes since v30:
* Fix typo (spotted by Kees Cook).
* Extend commit description (suggested by Kees Cook).
* Add note about what a Landlock user should do about OverlayFS
(requested by Kees Cook).
* Include inode and superblock documentation.
* Improve explanations about special filesystem limitations, and
highlight automatic /proc restrictions.
* Bump the last modification date.
Changes since v28:
* Reorder subsections by importance in the "Current limitations"
section.
Changes since v27:
* Update landlock_restrict_self(2).
* Update date and copyright.
Changes since v25:
* Explain the behavior of layered access rights.
* Explain how bind mounts and overayfs mounts are handled by Landlock:
merged overlayfs mount points have their own inodes, which makes these
hierarchies independent from its upper and lower layers, unlike bind
mounts which share the same inodes between the source hierarchy and
the mount point hierarchy.
New overlayfs mount and bind mount tests check these behaviors.
* Synchronize with the new syscalls.c file and update syscall names.
* Fix spelling.
* Remove Reviewed-by Jann Horn because of the above changes.
Changes since v24:
* Add Reviewed-by Jann Horn.
* Add a paragraph to explain how the ruleset layers work.
* Bump date.
Changes since v23:
* Explain limitations for the maximum number of stacked ruleset, and the
memory usage restrictions.
Changes since v22:
* Fix spelling and remove obsolete sentence (spotted by Jann Horn).
* Bump date.
Changes since v21:
* Move the user space documentation to userspace-api/landlock.rst and
the kernel documentation to security/landlock.rst .
* Add license headers.
* Add last update dates.
* Update MAINTAINERS file.
* Add (back) links to git.kernel.org .
* Fix spelling.
Changes since v20:
* Update examples and documentation with the new syscalls.
Changes since v19:
* Update examples and documentation with the new syscalls.
Changes since v15:
* Add current limitations.
Changes since v14:
* Fix spelling (contributed by Randy Dunlap).
* Extend documentation about inheritance and explain layer levels.
* Remove the use of now-removed access rights.
* Use GitHub links.
* Improve kernel documentation.
* Add section for tests.
* Update example.
Changes since v13:
* Rewrote the documentation according to the major revamp.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
Documentation/security/index.rst | 1 +
Documentation/security/landlock.rst | 85 +++++++
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/landlock.rst | 311 +++++++++++++++++++++++
MAINTAINERS | 2 +
5 files changed, 400 insertions(+)
create mode 100644 Documentation/security/landlock.rst
create mode 100644 Documentation/userspace-api/landlock.rst
diff --git a/Documentation/security/index.rst b/Documentation/security/index.rst
index 8129405eb2cc..16335de04e8c 100644
--- a/Documentation/security/index.rst
+++ b/Documentation/security/index.rst
@@ -16,3 +16,4 @@ Security Documentation
siphash
tpm/index
digsig
+ landlock
diff --git a/Documentation/security/landlock.rst b/Documentation/security/landlock.rst
new file mode 100644
index 000000000000..2e84925ae971
--- /dev/null
+++ b/Documentation/security/landlock.rst
@@ -0,0 +1,85 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+.. Copyright © 2019-2020 ANSSI
+
+==================================
+Landlock LSM: kernel documentation
+==================================
+
+:Author: Mickaël Salaün
+:Date: March 2021
+
+Landlock's goal is to create scoped access-control (i.e. sandboxing). To
+harden a whole system, this feature should be available to any process,
+including unprivileged ones. Because such process may be compromised or
+backdoored (i.e. untrusted), Landlock's features must be safe to use from the
+kernel and other processes point of view. Landlock's interface must therefore
+expose a minimal attack surface.
+
+Landlock is designed to be usable by unprivileged processes while following the
+system security policy enforced by other access control mechanisms (e.g. DAC,
+LSM). Indeed, a Landlock rule shall not interfere with other access-controls
+enforced on the system, only add more restrictions.
+
+Any user can enforce Landlock rulesets on their processes. They are merged and
+evaluated according to the inherited ones in a way that ensures that only more
+constraints can be added.
+
+User space documentation can be found here: :doc:`/userspace-api/landlock`.
+
+Guiding principles for safe access controls
+===========================================
+
+* A Landlock rule shall be focused on access control on kernel objects instead
+ of syscall filtering (i.e. syscall arguments), which is the purpose of
+ seccomp-bpf.
+* To avoid multiple kinds of side-channel attacks (e.g. leak of security
+ policies, CPU-based attacks), Landlock rules shall not be able to
+ programmatically communicate with user space.
+* Kernel access check shall not slow down access request from unsandboxed
+ processes.
+* Computation related to Landlock operations (e.g. enforcing a ruleset) shall
+ only impact the processes requesting them.
+
+Tests
+=====
+
+Userspace tests for backward compatibility, ptrace restrictions and filesystem
+support can be found here: `tools/testing/selftests/landlock/`_.
+
+Kernel structures
+=================
+
+Object
+------
+
+.. kernel-doc:: security/landlock/object.h
+ :identifiers:
+
+Filesystem
+----------
+
+.. kernel-doc:: security/landlock/fs.h
+ :identifiers:
+
+Ruleset and domain
+------------------
+
+A domain is a read-only ruleset tied to a set of subjects (i.e. tasks'
+credentials). Each time a ruleset is enforced on a task, the current domain is
+duplicated and the ruleset is imported as a new layer of rules in the new
+domain. Indeed, once in a domain, each rule is tied to a layer level. To
+grant access to an object, at least one rule of each layer must allow the
+requested action on the object. A task can then only transit to a new domain
+that is the intersection of the constraints from the current domain and those
+of a ruleset provided by the task.
+
+The definition of a subject is implicit for a task sandboxing itself, which
+makes the reasoning much easier and helps avoid pitfalls.
+
+.. kernel-doc:: security/landlock/ruleset.h
+ :identifiers:
+
+.. Links
+.. _tools/testing/selftests/landlock/:
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/tools/testing/selftests/landlock/
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index d29b020e5622..744c6491610c 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -18,6 +18,7 @@ place where this information is gathered.
no_new_privs
seccomp_filter
+ landlock
unshare
spec_ctrl
accelerators/ocxl
diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
new file mode 100644
index 000000000000..62c9361a3c7f
--- /dev/null
+++ b/Documentation/userspace-api/landlock.rst
@@ -0,0 +1,311 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+.. Copyright © 2019-2020 ANSSI
+.. Copyright © 2021 Microsoft Corporation
+
+=====================================
+Landlock: unprivileged access control
+=====================================
+
+:Author: Mickaël Salaün
+:Date: March 2021
+
+The goal of Landlock is to enable to restrict ambient rights (e.g. global
+filesystem access) for a set of processes. Because Landlock is a stackable
+LSM, it makes possible to create safe security sandboxes as new security layers
+in addition to the existing system-wide access-controls. This kind of sandbox
+is expected to help mitigate the security impact of bugs or
+unexpected/malicious behaviors in user space applications. Landlock empowers
+any process, including unprivileged ones, to securely restrict themselves.
+
+Landlock rules
+==============
+
+A Landlock rule describes an action on an object. An object is currently a
+file hierarchy, and the related filesystem actions are defined with `access
+rights`_. A set of rules is aggregated in a ruleset, which can then restrict
+the thread enforcing it, and its future children.
+
+Defining and enforcing a security policy
+----------------------------------------
+
+We first need to create the ruleset that will contain our rules. For this
+example, the ruleset will contain rules that only allow read actions, but write
+actions will be denied. The ruleset then needs to handle both of these kind of
+actions.
+
+.. code-block:: c
+
+ int ruleset_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs =
+ LANDLOCK_ACCESS_FS_EXECUTE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE |
+ LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_READ_DIR |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_MAKE_CHAR |
+ LANDLOCK_ACCESS_FS_MAKE_DIR |
+ LANDLOCK_ACCESS_FS_MAKE_REG |
+ LANDLOCK_ACCESS_FS_MAKE_SOCK |
+ LANDLOCK_ACCESS_FS_MAKE_FIFO |
+ LANDLOCK_ACCESS_FS_MAKE_BLOCK |
+ LANDLOCK_ACCESS_FS_MAKE_SYM,
+ };
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ if (ruleset_fd < 0) {
+ perror("Failed to create a ruleset");
+ return 1;
+ }
+
+We can now add a new rule to this ruleset thanks to the returned file
+descriptor referring to this ruleset. The rule will only allow reading the
+file hierarchy ``/usr``. Without another rule, write actions would then be
+denied by the ruleset. To add ``/usr`` to the ruleset, we open it with the
+``O_PATH`` flag and fill the &struct landlock_path_beneath_attr with this file
+descriptor.
+
+.. code-block:: c
+
+ int err;
+ struct landlock_path_beneath_attr path_beneath = {
+ .allowed_access =
+ LANDLOCK_ACCESS_FS_EXECUTE |
+ LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_READ_DIR,
+ };
+
+ path_beneath.parent_fd = open("/usr", O_PATH | O_CLOEXEC);
+ if (path_beneath.parent_fd < 0) {
+ perror("Failed to open file");
+ close(ruleset_fd);
+ return 1;
+ }
+ err = landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0);
+ close(path_beneath.parent_fd);
+ if (err) {
+ perror("Failed to update ruleset");
+ close(ruleset_fd);
+ return 1;
+ }
+
+We now have a ruleset with one rule allowing read access to ``/usr`` while
+denying all other handled accesses for the filesystem. The next step is to
+restrict the current thread from gaining more privileges (e.g. thanks to a SUID
+binary).
+
+.. code-block:: c
+
+ if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+ perror("Failed to restrict privileges");
+ close(ruleset_fd);
+ return 1;
+ }
+
+The current thread is now ready to sandbox itself with the ruleset.
+
+.. code-block:: c
+
+ if (landlock_restrict_self(ruleset_fd, 0)) {
+ perror("Failed to enforce ruleset");
+ close(ruleset_fd);
+ return 1;
+ }
+ close(ruleset_fd);
+
+If the `landlock_restrict_self` system call succeeds, the current thread is now
+restricted and this policy will be enforced on all its subsequently created
+children as well. Once a thread is landlocked, there is no way to remove its
+security policy; only adding more restrictions is allowed. These threads are
+now in a new Landlock domain, merge of their parent one (if any) with the new
+ruleset.
+
+Full working code can be found in `samples/landlock/sandboxer.c`_.
+
+Layers of file path access rights
+---------------------------------
+
+Each time a thread enforces a ruleset on itself, it updates its Landlock domain
+with a new layer of policy. Indeed, this complementary policy is stacked with
+the potentially other rulesets already restricting this thread. A sandboxed
+thread can then safely add more constraints to itself with a new enforced
+ruleset.
+
+One policy layer grants access to a file path if at least one of its rules
+encountered on the path grants the access. A sandboxed thread can only access
+a file path if all its enforced policy layers grant the access as well as all
+the other system access controls (e.g. filesystem DAC, other LSM policies,
+etc.).
+
+Bind mounts and OverlayFS
+-------------------------
+
+Landlock enables to restrict access to file hierarchies, which means that these
+access rights can be propagated with bind mounts (cf.
+:doc:`/filesystems/sharedsubtree`) but not with :doc:`/filesystems/overlayfs`.
+
+A bind mount mirrors a source file hierarchy to a destination. The destination
+hierarchy is then composed of the exact same files, on which Landlock rules can
+be tied, either via the source or the destination path. These rules restrict
+access when they are encountered on a path, which means that they can restrict
+access to multiple file hierarchies at the same time, whether these hierarchies
+are the result of bind mounts or not.
+
+An OverlayFS mount point consists of upper and lower layers. These layers are
+combined in a merge directory, result of the mount point. This merge hierarchy
+may include files from the upper and lower layers, but modifications performed
+on the merge hierarchy only reflects on the upper layer. From a Landlock
+policy point of view, each OverlayFS layers and merge hierarchies are
+standalone and contains their own set of files and directories, which is
+different from bind mounts. A policy restricting an OverlayFS layer will not
+restrict the resulted merged hierarchy, and vice versa. Landlock users should
+then only think about file hierarchies they want to allow access to, regardless
+of the underlying filesystem.
+
+Inheritance
+-----------
+
+Every new thread resulting from a :manpage:`clone(2)` inherits Landlock domain
+restrictions from its parent. This is similar to the seccomp inheritance (cf.
+:doc:`/userspace-api/seccomp_filter`) or any other LSM dealing with task's
+:manpage:`credentials(7)`. For instance, one process's thread may apply
+Landlock rules to itself, but they will not be automatically applied to other
+sibling threads (unlike POSIX thread credential changes, cf.
+:manpage:`nptl(7)`).
+
+When a thread sandboxes itself, we have the guarantee that the related security
+policy will stay enforced on all this thread's descendants. This allows
+creating standalone and modular security policies per application, which will
+automatically be composed between themselves according to their runtime parent
+policies.
+
+Ptrace restrictions
+-------------------
+
+A sandboxed process has less privileges than a non-sandboxed process and must
+then be subject to additional restrictions when manipulating another process.
+To be allowed to use :manpage:`ptrace(2)` and related syscalls on a target
+process, a sandboxed process should have a subset of the target process rules,
+which means the tracee must be in a sub-domain of the tracer.
+
+Kernel interface
+================
+
+Access rights
+-------------
+
+.. kernel-doc:: include/uapi/linux/landlock.h
+ :identifiers: fs_access
+
+Creating a new ruleset
+----------------------
+
+.. kernel-doc:: security/landlock/syscalls.c
+ :identifiers: sys_landlock_create_ruleset
+
+.. kernel-doc:: include/uapi/linux/landlock.h
+ :identifiers: landlock_ruleset_attr
+
+Extending a ruleset
+-------------------
+
+.. kernel-doc:: security/landlock/syscalls.c
+ :identifiers: sys_landlock_add_rule
+
+.. kernel-doc:: include/uapi/linux/landlock.h
+ :identifiers: landlock_rule_type landlock_path_beneath_attr
+
+Enforcing a ruleset
+-------------------
+
+.. kernel-doc:: security/landlock/syscalls.c
+ :identifiers: sys_landlock_restrict_self
+
+Current limitations
+===================
+
+File renaming and linking
+-------------------------
+
+Because Landlock targets unprivileged access controls, it is needed to properly
+handle composition of rules. Such property also implies rules nesting.
+Properly handling multiple layers of ruleset, each one of them able to restrict
+access to files, also implies to inherit the ruleset restrictions from a parent
+to its hierarchy. Because files are identified and restricted by their
+hierarchy, moving or linking a file from one directory to another implies to
+propagate the hierarchy constraints. To protect against privilege escalations
+through renaming or linking, and for the sake of simplicity, Landlock currently
+limits linking and renaming to the same directory. Future Landlock evolutions
+will enable more flexibility for renaming and linking, with dedicated ruleset
+flags.
+
+Filesystem topology modification
+--------------------------------
+
+As for file renaming and linking, a sandboxed thread cannot modify its
+filesystem topology, whether via :manpage:`mount(2)` or
+:manpage:`pivot_root(2)`. However, :manpage:`chroot(2)` calls are not denied.
+
+Special filesystems
+-------------------
+
+Access to regular files and directories can be restricted by Landlock,
+according to the handled accesses of a ruleset. However, files that do not
+come from a user-visible filesystem (e.g. pipe, socket), but can still be
+accessed through ``/proc/<pid>/fd/*``, cannot currently be explicitly
+restricted. Likewise, some special kernel filesystems such as nsfs, which can
+be accessed through ``/proc/<pid>/ns/*``, cannot currently be explicitly
+restricted. However, thanks to the `ptrace restrictions`_, access to such
+sensitive ``/proc`` files are automatically restricted according to domain
+hierarchies. Future Landlock evolutions could still enable to explicitly
+restrict such paths with dedicated ruleset flags.
+
+Ruleset layers
+--------------
+
+There is a limit of 64 layers of stacked rulesets. This can be an issue for a
+task willing to enforce a new ruleset in complement to its 64 inherited
+rulesets. Once this limit is reached, sys_landlock_restrict_self() returns
+E2BIG. It is then strongly suggested to carefully build rulesets once in the
+life of a thread, especially for applications able to launch other applications
+that may also want to sandbox themselves (e.g. shells, container managers,
+etc.).
+
+Memory usage
+------------
+
+Kernel memory allocated to create rulesets is accounted and can be restricted
+by the :doc:`/admin-guide/cgroup-v1/memory`.
+
+Questions and answers
+=====================
+
+What about user space sandbox managers?
+---------------------------------------
+
+Using user space process to enforce restrictions on kernel resources can lead
+to race conditions or inconsistent evaluations (i.e. `Incorrect mirroring of
+the OS code and state
+<https://www.ndss-symposium.org/ndss2003/traps-and-pitfalls-practical-problems-system-call-interposition-based-security-tools/>`_).
+
+What about namespaces and containers?
+-------------------------------------
+
+Namespaces can help create sandboxes but they are not designed for
+access-control and then miss useful features for such use case (e.g. no
+fine-grained restrictions). Moreover, their complexity can lead to security
+issues, especially when untrusted processes can manipulate them (cf.
+`Controlling access to user namespaces <https://lwn.net/Articles/673597/>`_).
+
+Additional documentation
+========================
+
+* :doc:`/security/landlock`
+* https://landlock.io
+
+.. Links
+.. _samples/landlock/sandboxer.c:
+ https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/samples/landlock/sandboxer.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 88175ed1f315..7b0c6de5946a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10003,6 +10003,8 @@ L: [email protected]
S: Supported
W: https://landlock.io
T: git https://github.com/landlock-lsm/linux.git
+F: Documentation/security/landlock.rst
+F: Documentation/userspace-api/landlock.rst
F: include/uapi/linux/landlock.h
F: samples/landlock/
F: security/landlock/
--
2.30.2
From: Mickaël Salaün <[email protected]>
Test all Landlock system calls, ptrace hooks semantic and filesystem
access-control with multiple layouts.
Test coverage for security/landlock/ is 93.6% of lines. The code not
covered only deals with internal kernel errors (e.g. memory allocation)
and race conditions.
Cc: James Morris <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Reviewed-by: Vincent Dagonneau <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
Changes since v32:
* Update the O_PATH test according to the relaxed landlock_add_rule(2).
Changes since v31:
* Following the hook_path_rename() and hook_path_link() changes, replace
some EACCESS checks with EXDEV when a reparenting is denied.
* Add Reviewed-by Kees Cook.
Changes since v29:
* Add new tests with chroot (parent directory).
* Extend test_make_file() and make_sym() to test link(2) and rename(2),
which helps cover get_mode_access().
Changes since v28:
* Creates a standalone filesystem test environement: do not update the
root mount point options, and creates a private mount hierarchy with a
deterministic filesystem (tmpfs). This is now possible thanks to
TEST_F_FORK().
* Factor out layout management with prepare_layout() and
cleanup_layout() for layout1, layout1_bind and layout2_overlay.
* Add and use a drop_caps() helper as much as possible (complementary to
the disable_caps() helper). This is possible for fs_test.c thanks to
TEST_F_FORK().
* Improve layout1.execute to make sure LANDLOCK_ACCESS_FS_EXECUTE only
restricts execve(2).
* Improve ptrace_test.c with /proc/<pid>/environ checks to also test
PTRACE_MODE_READ.
* Extend layout1.rename_file and layout1.rename_dir tests with
renameat2/RENAME_EXCHANGE and more comments.
* Tests unlinkat/AT_REMOVEDIR in complement to rmdir().
* Add a test to layout1.inval to check a rule with a ruleset as a
path_beneath.parent_fd .
* Add CONFIG_TMPFS_XATTR to avoid overlayfs warnings ("upper fs does not
support xattr, falling back to index=off and metacopy=off").
* Reduce capabilities use.
* Remove useless TH_LOG().
Changes since v27:
* Add layout1.non_overlapping_accesses to check rules without
overlapping access rights (fixed in this patchset).
* Extend layout1.interleaved_masked_accesses with a non-overlapping
execute-only rule.
* Update tests for empty path_beneath.allowed_access, and replace
useless (i.e. deny-only rules) code in
layout1.interleaved_masked_accesses with equivalent meaningful rules.
* Fix the returned step when a test failed with TEST_F_FORK().
* Update MAINTAINERS.
* Cosmetic fix to please checkpatch.
* Fix typo in comment.
* Update landlock_restrict_self(2).
Changes since v26:
* Add layout1_bind tests to check inherited bind mount accesses.
* Add layout2_overlay tests to check non-inherited overlayfs accesses.
* Fix final cleanup which was reordered because of kselftest_harness
changes.
* Update layout1.inherit_subset test according to the
check_access_path_layer() change.
* Implement TEST_F_FORK() to be able to use FIXTURE_TEARDOWN() to clean
up layouts even if the test (child) lost access rights or failed.
Remove now useless layout*.cleanup .
* Update syscall names.
* Clean up FIXTURE_SETUP(layout1).
* Clean up file layout management:
- Replace specific create_dir_and_file() with generic
create_directory() and create_file().
- Replace specific delete_dir_and_file() with generic remove_path().
- Rename and move cleanup_*() to remove_*() to improve readability.
- Use EXPECT_*() for all FIXTURE_TEARDOWN() code.
Changes since v25:
* Add a new test to check that Landlock ruleset file descriptors
received through UNIX sockets are usable. Contributed by Vincent
Dagonneau.
* Improve hierarchy.trace tests to not hang when testing on a kernel
that don't support Landlock.
* Replace EXPECT_EQ(0, close(*)) with ASSERT_EQ(0, close(*)).
* Guard WEXITSTATUS() use with WIFEXITED() in ptrace tests.
* Use pipe2(2) with O_CLOEXEC.
* Remove useless errno set for syscall wrappers, and related useless checks.
* Rename test.
* Add Microsoft copyright for layout1.interleaved_masked_accesses .
Changes since v24:
* Revert the ruleset_overlap test from v24: check that access righs are
ORed together when building a ruleset. Keep the extra checks
added with v24.
* Revert inherit_subset test from v24: use the automatic ORing of
access rights for the same file.
* Update interleaved_masked_accesses test (added with v24) to stop when
all layers allowed at least one time an inode in the path walk.
* Extend interleaved_masked_accesses test with new tricky interleaved
layers which would not work as intended with (allow or deny) bitmask
layer implementations.
* Simplify and rename test_path*() to test_open*() to make easier the
diagnostic in case of unattended errors.
* Replace most call to open(2) with a call to test_open(), which
reduces the number of lines and make tests more readable.
* Fix erroneous check in inherit_superset.
Changes since v23:
* Add an interleaved_masked_accesses test to check corner cases for
interleaved layered ruleset combinations.
* Update ruleset_overlap and inherit_subset tests to follow the new
intersect access rights behavior.
* Extend the inherit_superset test to check that layers are handled as
expected in the superset use case, which complete the inherit_subset
checks.
* Fix comment (spotted by Vincent Dagonneau).
Changes since v22:
* Extend and add a new test to better check rules applied to the root
directory: rule_over_root_allow_then_deny, rule_over_root_deny.
* Change the signature of test_path*() to make the calls clearer.
Changes since v21:
* Remove layout1.chroot test and update layout1.unhandled_access to not
rely on LANDLOCK_ACCESS_FS_CHROOT.
* Clean up comments.
Changes since v20:
* Update with new syscalls and type names.
* Use the full syscall interfaces: explicitely set the "flags" field to
zero.
* Update the empty_path_beneath_attr test to check for EFAULT.
* Update and merge tests for the simplified copy_min_struct_from_user().
* Clean up makefile.
* Rename some types and variables in a more consistent way.
Changes since v19:
* Update with the new Landlock syscalls.
* Fix device creation.
* Check the new landlock_attr_features members: last_rule_type and
last_target_type .
* Constify variables.
Changes since v18:
* Replace ruleset_rw.inval with layout1.inval to avoid inexistent test
layout.
* Use the new FIXTURE_VARIANT for ptrace_test: makes the tests more
readable and usable.
* Add ARRAY_SIZE() macro to please checkpatch.
Changes since v17:
* Add new test for mknod with a zero mode.
* Use memset(3) to initialize attr_features in base_test.
Changes since v16:
* Add new unpriv_enforce_without_no_new_privs test: check that ruleset
enforcing is forbiden without no_new_privs and CAP_SYS_ADMIN.
* Drop capabilities when useful.
* Check the new size_attr_features field from struct
landlock_attr_features.
* Update the empty_or_same_ruleset test to check complementary empty
ruleset.
* Update base_test according to the new attribute structures and fix the
inconsistent_attr test accordingly.
* Switch syscall attribute pointer and size arguments.
* Rename test files with a "_test" suffix.
Changes since v14:
* Add new tests:
- superset: check new layer bitmask.
- max_layers: check maximum number of layers.
- release_inodes: check that umount work well.
- empty_or_same_ruleset.
- inconsistent_attr: checks copy_to_user limits.
- in ruleset_rw.inval to check ruleset FD.
- proc_unlinked_file: check file access through /proc/self/fd .
- file_access_rights: check that a file can only get consistent access
rights.
- unpriv: check that NO_NEW_PRIVS or CAP_SYS_ADMIN is required.
- check pipe access through /proc/self/fd .
- check move_mount(2).
- check ruleset file descriptor properties.
- proc_nsfs: extend to check that internal filesystems (e.g. nsfs) are
allowed.
* Double-check read and write effective actions.
* Fix potential desynchronization between the kernel sources and
installed headers by overriding the build step in the Makefile. This
also enable to build with Clang.
* Add two files in the test directories (for link test and rename test).
* Remove test for ruleset's show_fdinfo().
* Replace EBADR with EBADFD.
* Update tests accordingly to the changes of rename and link rights.
* Fix (now) illegal access rights tied to files.
* Update rename and link tests.
* Remove superfluous '\n' in TH_LOG() calls.
* Make assert calls consistent and readable.
* Fix the execute test.
* Make tests future-proof.
* Cosmetic fixes.
Changes since v14:
* Add new tests:
- Compatibility: empty_attr_{ruleset,path_beneath,enforce} to check
minimal attr size.
- Access types: link_to, rename_from, rename_to, rmdir, unlink,
make_char, make_block, make_reg, make_sock, make_fifo, make_sym,
make_dir, chroot, execute.
- Test privilege escalation prevention by enforcing a nested rule, on
a parent directory, with less restrictions than one on a child
directory.
- Test for empty and more than 32-bits allowed_access
* Merge the two test mount hierarchies.
* Complete relative path tests by combining chdir and chroot.
* Adjust tests:
- Remove the layout1/extend_ruleset_with_denied_path test.
- Extend layout1/whitelist test with checks on file.
- Add and use create_dir_and_file().
* Only use read/write checks but not stat(2) for tests.
* Rename test.h to common.h and improve it.
* Rename path name to make them more consistent, easy to understand and
make them in a common directory.
* Make create_ruleset() more generic.
* Constify variables.
* Re-add static global variables.
* Remove useless openat(2).
* Fix and complete kernel config.
* Set umask and clean up file modes.
* Clean up open flags.
* Improve Makefile.
* Fix spelling.
* Improve comments and error messages.
Changes since v13:
* Add back the filesystem tests (from v10) and extend them.
* Add tests for the new syscall.
Previous changes:
https://lore.kernel.org/lkml/[email protected]/
---
MAINTAINERS | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/landlock/.gitignore | 2 +
tools/testing/selftests/landlock/Makefile | 24 +
tools/testing/selftests/landlock/base_test.c | 219 ++
tools/testing/selftests/landlock/common.h | 183 ++
tools/testing/selftests/landlock/config | 7 +
tools/testing/selftests/landlock/fs_test.c | 2791 +++++++++++++++++
.../testing/selftests/landlock/ptrace_test.c | 337 ++
tools/testing/selftests/landlock/true.c | 5 +
10 files changed, 3570 insertions(+)
create mode 100644 tools/testing/selftests/landlock/.gitignore
create mode 100644 tools/testing/selftests/landlock/Makefile
create mode 100644 tools/testing/selftests/landlock/base_test.c
create mode 100644 tools/testing/selftests/landlock/common.h
create mode 100644 tools/testing/selftests/landlock/config
create mode 100644 tools/testing/selftests/landlock/fs_test.c
create mode 100644 tools/testing/selftests/landlock/ptrace_test.c
create mode 100644 tools/testing/selftests/landlock/true.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 70ec117efa8a..8cab5854844e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10005,6 +10005,7 @@ W: https://landlock.io
T: git https://github.com/landlock-lsm/linux.git
F: include/uapi/linux/landlock.h
F: security/landlock/
+F: tools/testing/selftests/landlock/
K: landlock
K: LANDLOCK
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 6c575cf34a71..bc3299a20338 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -25,6 +25,7 @@ TARGETS += ir
TARGETS += kcmp
TARGETS += kexec
TARGETS += kvm
+TARGETS += landlock
TARGETS += lib
TARGETS += livepatch
TARGETS += lkdtm
diff --git a/tools/testing/selftests/landlock/.gitignore b/tools/testing/selftests/landlock/.gitignore
new file mode 100644
index 000000000000..470203a7cd73
--- /dev/null
+++ b/tools/testing/selftests/landlock/.gitignore
@@ -0,0 +1,2 @@
+/*_test
+/true
diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile
new file mode 100644
index 000000000000..a99596ca9882
--- /dev/null
+++ b/tools/testing/selftests/landlock/Makefile
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS += -Wall -O2
+
+src_test := $(wildcard *_test.c)
+
+TEST_GEN_PROGS := $(src_test:.c=)
+
+TEST_GEN_PROGS_EXTENDED := true
+
+KSFT_KHDR_INSTALL := 1
+OVERRIDE_TARGETS := 1
+include ../lib.mk
+
+khdr_dir = $(top_srcdir)/usr/include
+
+$(khdr_dir)/linux/landlock.h: khdr
+ @:
+
+$(OUTPUT)/true: true.c
+ $(LINK.c) $< $(LDLIBS) -o $@ -static
+
+$(OUTPUT)/%_test: %_test.c $(khdr_dir)/linux/landlock.h ../kselftest_harness.h common.h
+ $(LINK.c) $< $(LDLIBS) -o $@ -lcap -I$(khdr_dir)
diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
new file mode 100644
index 000000000000..262c3c8d953a
--- /dev/null
+++ b/tools/testing/selftests/landlock/base_test.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Landlock tests - Common user space base
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2019-2020 ANSSI
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include "common.h"
+
+#ifndef O_PATH
+#define O_PATH 010000000
+#endif
+
+TEST(inconsistent_attr) {
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *const buf = malloc(page_size + 1);
+ struct landlock_ruleset_attr *const ruleset_attr = (void *)buf;
+
+ ASSERT_NE(NULL, buf);
+
+ /* Checks copy_from_user(). */
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 0, 0));
+ /* The size if less than sizeof(struct landlock_attr_enforce). */
+ ASSERT_EQ(EINVAL, errno);
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 1, 0));
+ ASSERT_EQ(EINVAL, errno);
+
+ ASSERT_EQ(-1, landlock_create_ruleset(NULL, 1, 0));
+ /* The size if less than sizeof(struct landlock_attr_enforce). */
+ ASSERT_EQ(EFAULT, errno);
+
+ ASSERT_EQ(-1, landlock_create_ruleset(NULL,
+ sizeof(struct landlock_ruleset_attr), 0));
+ ASSERT_EQ(EFAULT, errno);
+
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
+ ASSERT_EQ(E2BIG, errno);
+
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr,
+ sizeof(struct landlock_ruleset_attr), 0));
+ ASSERT_EQ(ENOMSG, errno);
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
+ ASSERT_EQ(ENOMSG, errno);
+
+ /* Checks non-zero value. */
+ buf[page_size - 2] = '.';
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
+ ASSERT_EQ(E2BIG, errno);
+
+ ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
+ ASSERT_EQ(E2BIG, errno);
+
+ free(buf);
+}
+
+TEST(empty_path_beneath_attr) {
+ const struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
+ };
+ const int ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Similar to struct landlock_path_beneath_attr.parent_fd = 0 */
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ NULL, 0));
+ ASSERT_EQ(EFAULT, errno);
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+TEST(inval_fd_enforce) {
+ ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+
+ ASSERT_EQ(-1, landlock_restrict_self(-1, 0));
+ ASSERT_EQ(EBADF, errno);
+}
+
+TEST(unpriv_enforce_without_no_new_privs) {
+ int err;
+
+ drop_caps(_metadata);
+ err = landlock_restrict_self(-1, 0);
+ ASSERT_EQ(EPERM, errno);
+ ASSERT_EQ(err, -1);
+}
+
+TEST(ruleset_fd_io)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
+ };
+ int ruleset_fd;
+ char buf;
+
+ drop_caps(_metadata);
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(-1, write(ruleset_fd, ".", 1));
+ ASSERT_EQ(EINVAL, errno);
+ ASSERT_EQ(-1, read(ruleset_fd, &buf, 1));
+ ASSERT_EQ(EINVAL, errno);
+
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+/* Tests enforcement of a ruleset FD transferred through a UNIX socket. */
+TEST(ruleset_fd_transfer)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
+ };
+ struct landlock_path_beneath_attr path_beneath_attr = {
+ .allowed_access = LANDLOCK_ACCESS_FS_READ_DIR,
+ };
+ int ruleset_fd_tx, dir_fd;
+ union {
+ /* Aligned ancillary data buffer. */
+ char buf[CMSG_SPACE(sizeof(ruleset_fd_tx))];
+ struct cmsghdr _align;
+ } cmsg_tx = {};
+ char data_tx = '.';
+ struct iovec io = {
+ .iov_base = &data_tx,
+ .iov_len = sizeof(data_tx),
+ };
+ struct msghdr msg = {
+ .msg_iov = &io,
+ .msg_iovlen = 1,
+ .msg_control = &cmsg_tx.buf,
+ .msg_controllen = sizeof(cmsg_tx.buf),
+ };
+ struct cmsghdr *cmsg;
+ int socket_fds[2];
+ pid_t child;
+ int status;
+
+ drop_caps(_metadata);
+
+ /* Creates a test ruleset with a simple rule. */
+ ruleset_fd_tx = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd_tx);
+ path_beneath_attr.parent_fd = open("/tmp", O_PATH | O_NOFOLLOW |
+ O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, path_beneath_attr.parent_fd);
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd_tx, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath_attr, 0));
+ ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ ASSERT_NE(NULL, cmsg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(ruleset_fd_tx));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ memcpy(CMSG_DATA(cmsg), &ruleset_fd_tx, sizeof(ruleset_fd_tx));
+
+ /* Sends the ruleset FD over a socketpair and then close it. */
+ ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, socket_fds));
+ ASSERT_EQ(sizeof(data_tx), sendmsg(socket_fds[0], &msg, 0));
+ ASSERT_EQ(0, close(socket_fds[0]));
+ ASSERT_EQ(0, close(ruleset_fd_tx));
+
+ child = fork();
+ ASSERT_LE(0, child);
+ if (child == 0) {
+ int ruleset_fd_rx;
+
+ *(char *)msg.msg_iov->iov_base = '\0';
+ ASSERT_EQ(sizeof(data_tx), recvmsg(socket_fds[1], &msg, MSG_CMSG_CLOEXEC));
+ ASSERT_EQ('.', *(char *)msg.msg_iov->iov_base);
+ ASSERT_EQ(0, close(socket_fds[1]));
+ cmsg = CMSG_FIRSTHDR(&msg);
+ ASSERT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(ruleset_fd_tx)));
+ memcpy(&ruleset_fd_rx, CMSG_DATA(cmsg), sizeof(ruleset_fd_tx));
+
+ /* Enforces the received ruleset on the child. */
+ ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+ ASSERT_EQ(0, landlock_restrict_self(ruleset_fd_rx, 0));
+ ASSERT_EQ(0, close(ruleset_fd_rx));
+
+ /* Checks that the ruleset enforcement. */
+ ASSERT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
+ ASSERT_EQ(EACCES, errno);
+ dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, dir_fd);
+ ASSERT_EQ(0, close(dir_fd));
+ _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
+ return;
+ }
+
+ ASSERT_EQ(0, close(socket_fds[1]));
+
+ /* Checks that the parent is unrestricted. */
+ dir_fd = open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, dir_fd);
+ ASSERT_EQ(0, close(dir_fd));
+ dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, dir_fd);
+ ASSERT_EQ(0, close(dir_fd));
+
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFEXITED(status));
+ ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/landlock/common.h b/tools/testing/selftests/landlock/common.h
new file mode 100644
index 000000000000..20e2a9286d71
--- /dev/null
+++ b/tools/testing/selftests/landlock/common.h
@@ -0,0 +1,183 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Landlock test helpers
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2019-2020 ANSSI
+ * Copyright © 2021 Microsoft Corporation
+ */
+
+#include <errno.h>
+#include <linux/landlock.h>
+#include <sys/capability.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "../kselftest_harness.h"
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+/*
+ * TEST_F_FORK() is useful when a test drop privileges but the corresponding
+ * FIXTURE_TEARDOWN() requires them (e.g. to remove files from a directory
+ * where write actions are denied). For convenience, FIXTURE_TEARDOWN() is
+ * also called when the test failed, but not when FIXTURE_SETUP() failed. For
+ * this to be possible, we must not call abort() but instead exit smoothly
+ * (hence the step print).
+ */
+#define TEST_F_FORK(fixture_name, test_name) \
+ static void fixture_name##_##test_name##_child( \
+ struct __test_metadata *_metadata, \
+ FIXTURE_DATA(fixture_name) *self, \
+ const FIXTURE_VARIANT(fixture_name) *variant); \
+ TEST_F(fixture_name, test_name) \
+ { \
+ int status; \
+ const pid_t child = fork(); \
+ if (child < 0) \
+ abort(); \
+ if (child == 0) { \
+ _metadata->no_print = 1; \
+ fixture_name##_##test_name##_child(_metadata, self, variant); \
+ if (_metadata->skip) \
+ _exit(255); \
+ if (_metadata->passed) \
+ _exit(0); \
+ _exit(_metadata->step); \
+ } \
+ if (child != waitpid(child, &status, 0)) \
+ abort(); \
+ if (WIFSIGNALED(status) || !WIFEXITED(status)) { \
+ _metadata->passed = 0; \
+ _metadata->step = 1; \
+ return; \
+ } \
+ switch (WEXITSTATUS(status)) { \
+ case 0: \
+ _metadata->passed = 1; \
+ break; \
+ case 255: \
+ _metadata->passed = 1; \
+ _metadata->skip = 1; \
+ break; \
+ default: \
+ _metadata->passed = 0; \
+ _metadata->step = WEXITSTATUS(status); \
+ break; \
+ } \
+ } \
+ static void fixture_name##_##test_name##_child( \
+ struct __test_metadata __attribute__((unused)) *_metadata, \
+ FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \
+ const FIXTURE_VARIANT(fixture_name) \
+ __attribute__((unused)) *variant)
+
+#ifndef landlock_create_ruleset
+static inline int landlock_create_ruleset(
+ const struct landlock_ruleset_attr *const attr,
+ const size_t size, const __u32 flags)
+{
+ return syscall(__NR_landlock_create_ruleset, attr, size, flags);
+}
+#endif
+
+#ifndef landlock_add_rule
+static inline int landlock_add_rule(const int ruleset_fd,
+ const enum landlock_rule_type rule_type,
+ const void *const rule_attr, const __u32 flags)
+{
+ return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type,
+ rule_attr, flags);
+}
+#endif
+
+#ifndef landlock_restrict_self
+static inline int landlock_restrict_self(const int ruleset_fd,
+ const __u32 flags)
+{
+ return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
+}
+#endif
+
+static void _init_caps(struct __test_metadata *const _metadata, bool drop_all)
+{
+ cap_t cap_p;
+ /* Only these three capabilities are useful for the tests. */
+ const cap_value_t caps[] = {
+ CAP_DAC_OVERRIDE,
+ CAP_MKNOD,
+ CAP_SYS_ADMIN,
+ CAP_SYS_CHROOT,
+ };
+
+ cap_p = cap_get_proc();
+ EXPECT_NE(NULL, cap_p) {
+ TH_LOG("Failed to cap_get_proc: %s", strerror(errno));
+ }
+ EXPECT_NE(-1, cap_clear(cap_p)) {
+ TH_LOG("Failed to cap_clear: %s", strerror(errno));
+ }
+ if (!drop_all) {
+ EXPECT_NE(-1, cap_set_flag(cap_p, CAP_PERMITTED,
+ ARRAY_SIZE(caps), caps, CAP_SET)) {
+ TH_LOG("Failed to cap_set_flag: %s", strerror(errno));
+ }
+ }
+ EXPECT_NE(-1, cap_set_proc(cap_p)) {
+ TH_LOG("Failed to cap_set_proc: %s", strerror(errno));
+ }
+ EXPECT_NE(-1, cap_free(cap_p)) {
+ TH_LOG("Failed to cap_free: %s", strerror(errno));
+ }
+}
+
+/* We cannot put such helpers in a library because of kselftest_harness.h . */
+__attribute__((__unused__))
+static void disable_caps(struct __test_metadata *const _metadata)
+{
+ _init_caps(_metadata, false);
+}
+
+__attribute__((__unused__))
+static void drop_caps(struct __test_metadata *const _metadata)
+{
+ _init_caps(_metadata, true);
+}
+
+static void _effective_cap(struct __test_metadata *const _metadata,
+ const cap_value_t caps, const cap_flag_value_t value)
+{
+ cap_t cap_p;
+
+ cap_p = cap_get_proc();
+ EXPECT_NE(NULL, cap_p) {
+ TH_LOG("Failed to cap_get_proc: %s", strerror(errno));
+ }
+ EXPECT_NE(-1, cap_set_flag(cap_p, CAP_EFFECTIVE, 1, &caps, value)) {
+ TH_LOG("Failed to cap_set_flag: %s", strerror(errno));
+ }
+ EXPECT_NE(-1, cap_set_proc(cap_p)) {
+ TH_LOG("Failed to cap_set_proc: %s", strerror(errno));
+ }
+ EXPECT_NE(-1, cap_free(cap_p)) {
+ TH_LOG("Failed to cap_free: %s", strerror(errno));
+ }
+}
+
+__attribute__((__unused__))
+static void set_cap(struct __test_metadata *const _metadata,
+ const cap_value_t caps)
+{
+ _effective_cap(_metadata, caps, CAP_SET);
+}
+
+__attribute__((__unused__))
+static void clear_cap(struct __test_metadata *const _metadata,
+ const cap_value_t caps)
+{
+ _effective_cap(_metadata, caps, CAP_CLEAR);
+}
diff --git a/tools/testing/selftests/landlock/config b/tools/testing/selftests/landlock/config
new file mode 100644
index 000000000000..0f0a65287bac
--- /dev/null
+++ b/tools/testing/selftests/landlock/config
@@ -0,0 +1,7 @@
+CONFIG_OVERLAY_FS=y
+CONFIG_SECURITY_LANDLOCK=y
+CONFIG_SECURITY_PATH=y
+CONFIG_SECURITY=y
+CONFIG_SHMEM=y
+CONFIG_TMPFS_XATTR=y
+CONFIG_TMPFS=y
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
new file mode 100644
index 000000000000..10c9a1e4ebd9
--- /dev/null
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -0,0 +1,2791 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Landlock tests - Filesystem
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2020 ANSSI
+ * Copyright © 2020-2021 Microsoft Corporation
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/capability.h>
+#include <sys/mount.h>
+#include <sys/prctl.h>
+#include <sys/sendfile.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
+
+#include "common.h"
+
+#define TMP_DIR "tmp"
+#define BINARY_PATH "./true"
+
+/* Paths (sibling number and depth) */
+static const char dir_s1d1[] = TMP_DIR "/s1d1";
+static const char file1_s1d1[] = TMP_DIR "/s1d1/f1";
+static const char file2_s1d1[] = TMP_DIR "/s1d1/f2";
+static const char dir_s1d2[] = TMP_DIR "/s1d1/s1d2";
+static const char file1_s1d2[] = TMP_DIR "/s1d1/s1d2/f1";
+static const char file2_s1d2[] = TMP_DIR "/s1d1/s1d2/f2";
+static const char dir_s1d3[] = TMP_DIR "/s1d1/s1d2/s1d3";
+static const char file1_s1d3[] = TMP_DIR "/s1d1/s1d2/s1d3/f1";
+static const char file2_s1d3[] = TMP_DIR "/s1d1/s1d2/s1d3/f2";
+
+static const char dir_s2d1[] = TMP_DIR "/s2d1";
+static const char file1_s2d1[] = TMP_DIR "/s2d1/f1";
+static const char dir_s2d2[] = TMP_DIR "/s2d1/s2d2";
+static const char file1_s2d2[] = TMP_DIR "/s2d1/s2d2/f1";
+static const char dir_s2d3[] = TMP_DIR "/s2d1/s2d2/s2d3";
+static const char file1_s2d3[] = TMP_DIR "/s2d1/s2d2/s2d3/f1";
+static const char file2_s2d3[] = TMP_DIR "/s2d1/s2d2/s2d3/f2";
+
+static const char dir_s3d1[] = TMP_DIR "/s3d1";
+/* dir_s3d2 is a mount point. */
+static const char dir_s3d2[] = TMP_DIR "/s3d1/s3d2";
+static const char dir_s3d3[] = TMP_DIR "/s3d1/s3d2/s3d3";
+
+/*
+ * layout1 hierarchy:
+ *
+ * tmp
+ * ├── s1d1
+ * │ ├── f1
+ * │ ├── f2
+ * │ └── s1d2
+ * │ ├── f1
+ * │ ├── f2
+ * │ └── s1d3
+ * │ ├── f1
+ * │ └── f2
+ * ├── s2d1
+ * │ ├── f1
+ * │ └── s2d2
+ * │ ├── f1
+ * │ └── s2d3
+ * │ ├── f1
+ * │ └── f2
+ * └── s3d1
+ * └── s3d2
+ * └── s3d3
+ */
+
+static void mkdir_parents(struct __test_metadata *const _metadata,
+ const char *const path)
+{
+ char *walker;
+ const char *parent;
+ int i, err;
+
+ ASSERT_NE(path[0], '\0');
+ walker = strdup(path);
+ ASSERT_NE(NULL, walker);
+ parent = walker;
+ for (i = 1; walker[i]; i++) {
+ if (walker[i] != '/')
+ continue;
+ walker[i] = '\0';
+ err = mkdir(parent, 0700);
+ ASSERT_FALSE(err && errno != EEXIST) {
+ TH_LOG("Failed to create directory \"%s\": %s",
+ parent, strerror(errno));
+ }
+ walker[i] = '/';
+ }
+ free(walker);
+}
+
+static void create_directory(struct __test_metadata *const _metadata,
+ const char *const path)
+{
+ mkdir_parents(_metadata, path);
+ ASSERT_EQ(0, mkdir(path, 0700)) {
+ TH_LOG("Failed to create directory \"%s\": %s", path,
+ strerror(errno));
+ }
+}
+
+static void create_file(struct __test_metadata *const _metadata,
+ const char *const path)
+{
+ mkdir_parents(_metadata, path);
+ ASSERT_EQ(0, mknod(path, S_IFREG | 0700, 0)) {
+ TH_LOG("Failed to create file \"%s\": %s", path,
+ strerror(errno));
+ }
+}
+
+static int remove_path(const char *const path)
+{
+ char *walker;
+ int i, ret, err = 0;
+
+ walker = strdup(path);
+ if (!walker) {
+ err = ENOMEM;
+ goto out;
+ }
+ if (unlink(path) && rmdir(path)) {
+ if (errno != ENOENT)
+ err = errno;
+ goto out;
+ }
+ for (i = strlen(walker); i > 0; i--) {
+ if (walker[i] != '/')
+ continue;
+ walker[i] = '\0';
+ ret = rmdir(walker);
+ if (ret) {
+ if (errno != ENOTEMPTY && errno != EBUSY)
+ err = errno;
+ goto out;
+ }
+ if (strcmp(walker, TMP_DIR) == 0)
+ goto out;
+ }
+
+out:
+ free(walker);
+ return err;
+}
+
+static void prepare_layout(struct __test_metadata *const _metadata)
+{
+ disable_caps(_metadata);
+ umask(0077);
+ create_directory(_metadata, TMP_DIR);
+
+ /*
+ * Do not pollute the rest of the system: creates a private mount point
+ * for tests relying on pivot_root(2) and move_mount(2).
+ */
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, unshare(CLONE_NEWNS));
+ ASSERT_EQ(0, mount("tmp", TMP_DIR, "tmpfs", 0, "size=4m,mode=700"));
+ ASSERT_EQ(0, mount(NULL, TMP_DIR, NULL, MS_PRIVATE | MS_REC, NULL));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+static void cleanup_layout(struct __test_metadata *const _metadata)
+{
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, umount(TMP_DIR));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, remove_path(TMP_DIR));
+}
+
+static void create_layout1(struct __test_metadata *const _metadata)
+{
+ create_file(_metadata, file1_s1d1);
+ create_file(_metadata, file1_s1d2);
+ create_file(_metadata, file1_s1d3);
+ create_file(_metadata, file2_s1d1);
+ create_file(_metadata, file2_s1d2);
+ create_file(_metadata, file2_s1d3);
+
+ create_file(_metadata, file1_s2d1);
+ create_file(_metadata, file1_s2d2);
+ create_file(_metadata, file1_s2d3);
+ create_file(_metadata, file2_s2d3);
+
+ create_directory(_metadata, dir_s3d2);
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, mount("tmp", dir_s3d2, "tmpfs", 0, "size=4m,mode=700"));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+
+ ASSERT_EQ(0, mkdir(dir_s3d3, 0700));
+}
+
+static void remove_layout1(struct __test_metadata *const _metadata)
+{
+ EXPECT_EQ(0, remove_path(file2_s1d3));
+ EXPECT_EQ(0, remove_path(file2_s1d2));
+ EXPECT_EQ(0, remove_path(file2_s1d1));
+ EXPECT_EQ(0, remove_path(file1_s1d3));
+ EXPECT_EQ(0, remove_path(file1_s1d2));
+ EXPECT_EQ(0, remove_path(file1_s1d1));
+
+ EXPECT_EQ(0, remove_path(file2_s2d3));
+ EXPECT_EQ(0, remove_path(file1_s2d3));
+ EXPECT_EQ(0, remove_path(file1_s2d2));
+ EXPECT_EQ(0, remove_path(file1_s2d1));
+
+ EXPECT_EQ(0, remove_path(dir_s3d3));
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ umount(dir_s3d2);
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, remove_path(dir_s3d2));
+}
+
+FIXTURE(layout1) {
+};
+
+FIXTURE_SETUP(layout1)
+{
+ prepare_layout(_metadata);
+
+ create_layout1(_metadata);
+}
+
+FIXTURE_TEARDOWN(layout1)
+{
+ remove_layout1(_metadata);
+
+ cleanup_layout(_metadata);
+}
+
+/*
+ * This helper enables to use the ASSERT_* macros and print the line number
+ * pointing to the test caller.
+ */
+static int test_open_rel(const int dirfd, const char *const path, const int flags)
+{
+ int fd;
+
+ /* Works with file and directories. */
+ fd = openat(dirfd, path, flags | O_CLOEXEC);
+ if (fd < 0)
+ return errno;
+ /*
+ * Mixing error codes from close(2) and open(2) should not lead to any
+ * (access type) confusion for this test.
+ */
+ if (close(fd) != 0)
+ return errno;
+ return 0;
+}
+
+static int test_open(const char *const path, const int flags)
+{
+ return test_open_rel(AT_FDCWD, path, flags);
+}
+
+TEST_F_FORK(layout1, no_restriction)
+{
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(dir_s2d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s2d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s2d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(dir_s3d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d3, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, inval)
+{
+ struct landlock_path_beneath_attr path_beneath = {
+ .allowed_access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ .parent_fd = -1,
+ };
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ };
+ int ruleset_fd;
+
+ path_beneath.parent_fd = open(dir_s1d2, O_PATH | O_DIRECTORY |
+ O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd);
+
+ ruleset_fd = open(dir_s1d1, O_PATH | O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, ruleset_fd);
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ /* Returns EBADF because ruleset_fd is not a landlock-ruleset FD. */
+ ASSERT_EQ(EBADF, errno);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ruleset_fd = open(dir_s1d1, O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, ruleset_fd);
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ /* Returns EBADFD because ruleset_fd is not a valid ruleset. */
+ ASSERT_EQ(EBADFD, errno);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Gets a real ruleset. */
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+
+ /* Tests without O_PATH. */
+ path_beneath.parent_fd = open(dir_s1d2, O_DIRECTORY | O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd);
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+
+ /* Tests with a ruleset FD. */
+ path_beneath.parent_fd = ruleset_fd;
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(EBADFD, errno);
+
+ /* Checks unhandled allowed_access. */
+ path_beneath.parent_fd = open(dir_s1d2, O_PATH | O_DIRECTORY |
+ O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd);
+
+ /* Test with legitimate values. */
+ path_beneath.allowed_access |= LANDLOCK_ACCESS_FS_EXECUTE;
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(EINVAL, errno);
+ path_beneath.allowed_access &= ~LANDLOCK_ACCESS_FS_EXECUTE;
+
+ /* Test with unknown (64-bits) value. */
+ path_beneath.allowed_access |= (1ULL << 60);
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(EINVAL, errno);
+ path_beneath.allowed_access &= ~(1ULL << 60);
+
+ /* Test with no access. */
+ path_beneath.allowed_access = 0;
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(ENOMSG, errno);
+ path_beneath.allowed_access &= ~(1ULL << 60);
+
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+
+ /* Enforces the ruleset. */
+ ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+ ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
+
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+#define ACCESS_FILE ( \
+ LANDLOCK_ACCESS_FS_EXECUTE | \
+ LANDLOCK_ACCESS_FS_WRITE_FILE | \
+ LANDLOCK_ACCESS_FS_READ_FILE)
+
+#define ACCESS_LAST LANDLOCK_ACCESS_FS_MAKE_SYM
+
+#define ACCESS_ALL ( \
+ ACCESS_FILE | \
+ LANDLOCK_ACCESS_FS_READ_DIR | \
+ LANDLOCK_ACCESS_FS_REMOVE_DIR | \
+ LANDLOCK_ACCESS_FS_REMOVE_FILE | \
+ LANDLOCK_ACCESS_FS_MAKE_CHAR | \
+ LANDLOCK_ACCESS_FS_MAKE_DIR | \
+ LANDLOCK_ACCESS_FS_MAKE_REG | \
+ LANDLOCK_ACCESS_FS_MAKE_SOCK | \
+ LANDLOCK_ACCESS_FS_MAKE_FIFO | \
+ LANDLOCK_ACCESS_FS_MAKE_BLOCK | \
+ ACCESS_LAST)
+
+TEST_F_FORK(layout1, file_access_rights)
+{
+ __u64 access;
+ int err;
+ struct landlock_path_beneath_attr path_beneath = {};
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_ALL,
+ };
+ const int ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Tests access rights for files. */
+ path_beneath.parent_fd = open(file1_s1d2, O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd);
+ for (access = 1; access <= ACCESS_LAST; access <<= 1) {
+ path_beneath.allowed_access = access;
+ err = landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0);
+ if ((access | ACCESS_FILE) == ACCESS_FILE) {
+ ASSERT_EQ(0, err);
+ } else {
+ ASSERT_EQ(-1, err);
+ ASSERT_EQ(EINVAL, errno);
+ }
+ }
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+}
+
+static void add_path_beneath(struct __test_metadata *const _metadata,
+ const int ruleset_fd, const __u64 allowed_access,
+ const char *const path)
+{
+ struct landlock_path_beneath_attr path_beneath = {
+ .allowed_access = allowed_access,
+ };
+
+ path_beneath.parent_fd = open(path, O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd) {
+ TH_LOG("Failed to open directory \"%s\": %s", path,
+ strerror(errno));
+ }
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0)) {
+ TH_LOG("Failed to update the ruleset with \"%s\": %s", path,
+ strerror(errno));
+ }
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+}
+
+struct rule {
+ const char *path;
+ __u64 access;
+};
+
+#define ACCESS_RO ( \
+ LANDLOCK_ACCESS_FS_READ_FILE | \
+ LANDLOCK_ACCESS_FS_READ_DIR)
+
+#define ACCESS_RW ( \
+ ACCESS_RO | \
+ LANDLOCK_ACCESS_FS_WRITE_FILE)
+
+static int create_ruleset(struct __test_metadata *const _metadata,
+ const __u64 handled_access_fs, const struct rule rules[])
+{
+ int ruleset_fd, i;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = handled_access_fs,
+ };
+
+ ASSERT_NE(NULL, rules) {
+ TH_LOG("No rule list");
+ }
+ ASSERT_NE(NULL, rules[0].path) {
+ TH_LOG("Empty rule list");
+ }
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd) {
+ TH_LOG("Failed to create a ruleset: %s", strerror(errno));
+ }
+
+ for (i = 0; rules[i].path; i++) {
+ add_path_beneath(_metadata, ruleset_fd, rules[i].access,
+ rules[i].path);
+ }
+ return ruleset_fd;
+}
+
+static void enforce_ruleset(struct __test_metadata *const _metadata,
+ const int ruleset_fd)
+{
+ ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+ ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)) {
+ TH_LOG("Failed to enforce ruleset: %s", strerror(errno));
+ }
+}
+
+TEST_F_FORK(layout1, proc_nsfs)
+{
+ const struct rule rules[] = {
+ {
+ .path = "/dev/null",
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ struct landlock_path_beneath_attr path_beneath;
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access |
+ LANDLOCK_ACCESS_FS_READ_DIR, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ ASSERT_EQ(0, test_open("/proc/self/ns/mnt", O_RDONLY));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ ASSERT_EQ(EACCES, test_open("/", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open("/dev", O_RDONLY));
+ ASSERT_EQ(0, test_open("/dev/null", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open("/dev/full", O_RDONLY));
+
+ ASSERT_EQ(EACCES, test_open("/proc", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open("/proc/self", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open("/proc/self/ns", O_RDONLY));
+ /*
+ * Because nsfs is an internal filesystem, /proc/self/ns/mnt is a
+ * disconnected path. Such path cannot be identified and must then be
+ * allowed.
+ */
+ ASSERT_EQ(0, test_open("/proc/self/ns/mnt", O_RDONLY));
+
+ /*
+ * Checks that it is not possible to add nsfs-like filesystem
+ * references to a ruleset.
+ */
+ path_beneath.allowed_access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ path_beneath.parent_fd = open("/proc/self/ns/mnt", O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, path_beneath.parent_fd);
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(EBADFD, errno);
+ ASSERT_EQ(0, close(path_beneath.parent_fd));
+}
+
+TEST_F_FORK(layout1, unpriv) {
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ int ruleset_fd;
+
+ drop_caps(_metadata);
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RO, rules);
+ ASSERT_LE(0, ruleset_fd);
+ ASSERT_EQ(-1, landlock_restrict_self(ruleset_fd, 0));
+ ASSERT_EQ(EPERM, errno);
+
+ /* enforce_ruleset() calls prctl(no_new_privs). */
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F_FORK(layout1, effective_access)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = ACCESS_RO,
+ },
+ {
+ .path = file1_s2d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+ char buf;
+ int reg_fd;
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Tests on a directory. */
+ ASSERT_EQ(EACCES, test_open("/", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+
+ /* Tests on a file. */
+ ASSERT_EQ(EACCES, test_open(dir_s2d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d2, O_RDONLY));
+
+ /* Checks effective read and write actions. */
+ reg_fd = open(file1_s2d2, O_RDWR | O_CLOEXEC);
+ ASSERT_LE(0, reg_fd);
+ ASSERT_EQ(1, write(reg_fd, ".", 1));
+ ASSERT_LE(0, lseek(reg_fd, 0, SEEK_SET));
+ ASSERT_EQ(1, read(reg_fd, &buf, 1));
+ ASSERT_EQ('.', buf);
+ ASSERT_EQ(0, close(reg_fd));
+
+ /* Just in case, double-checks effective actions. */
+ reg_fd = open(file1_s2d2, O_RDONLY | O_CLOEXEC);
+ ASSERT_LE(0, reg_fd);
+ ASSERT_EQ(-1, write(reg_fd, &buf, 1));
+ ASSERT_EQ(EBADF, errno);
+ ASSERT_EQ(0, close(reg_fd));
+}
+
+TEST_F_FORK(layout1, unhandled_access)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ /* Here, we only handle read accesses, not write accesses. */
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RO, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Because the policy does not handle LANDLOCK_ACCESS_FS_WRITE_FILE,
+ * opening for write-only should be allowed, but not read-write.
+ */
+ ASSERT_EQ(0, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDWR));
+
+ ASSERT_EQ(0, test_open(file1_s1d2, O_WRONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDWR));
+}
+
+TEST_F_FORK(layout1, ruleset_overlap)
+{
+ const struct rule rules[] = {
+ /* These rules should be ORed among them. */
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_READ_DIR,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks s1d1 hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDWR));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ /* Checks s1d2 hierarchy. */
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_WRONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDWR));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* Checks s1d3 hierarchy. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDWR));
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+}
+
+TEST_F_FORK(layout1, non_overlapping_accesses)
+{
+ const struct rule layer1[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_MAKE_REG,
+ },
+ {}
+ };
+ const struct rule layer2[] = {
+ {
+ .path = dir_s1d3,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {}
+ };
+ int ruleset_fd;
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_MAKE_REG,
+ layer1);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, mknod(file1_s1d1, S_IFREG | 0700, 0));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(0, mknod(file1_s1d2, S_IFREG | 0700, 0));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ layer2);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Unchanged accesses for file creation. */
+ ASSERT_EQ(-1, mknod(file1_s1d1, S_IFREG | 0700, 0));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(0, mknod(file1_s1d2, S_IFREG | 0700, 0));
+
+ /* Checks file removing. */
+ ASSERT_EQ(-1, unlink(file1_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(0, unlink(file1_s1d3));
+}
+
+TEST_F_FORK(layout1, interleaved_masked_accesses)
+{
+ /*
+ * Checks overly restrictive rules:
+ * layer 1: allows R s1d1/s1d2/s1d3/file1
+ * layer 2: allows RW s1d1/s1d2/s1d3
+ * allows W s1d1/s1d2
+ * denies R s1d1/s1d2
+ * layer 3: allows R s1d1
+ * layer 4: allows R s1d1/s1d2
+ * denies W s1d1/s1d2
+ * layer 5: allows R s1d1/s1d2
+ * layer 6: allows X ----
+ * layer 7: allows W s1d1/s1d2
+ * denies R s1d1/s1d2
+ */
+ const struct rule layer1_read[] = {
+ /* Allows read access to file1_s1d3 with the first layer. */
+ {
+ .path = file1_s1d3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ /* First rule with write restrictions. */
+ const struct rule layer2_read_write[] = {
+ /* Start by granting read-write access via its parent directory... */
+ {
+ .path = dir_s1d3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ /* ...but also denies read access via its grandparent directory. */
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ const struct rule layer3_read[] = {
+ /* Allows read access via its great-grandparent directory. */
+ {
+ .path = dir_s1d1,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ const struct rule layer4_read_write[] = {
+ /*
+ * Try to confuse the deny access by denying write (but not
+ * read) access via its grandparent directory.
+ */
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ const struct rule layer5_read[] = {
+ /*
+ * Try to override layer2's deny read access by explicitly
+ * allowing read access via file1_s1d3's grandparent.
+ */
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ const struct rule layer6_execute[] = {
+ /*
+ * Restricts an unrelated file hierarchy with a new access
+ * (non-overlapping) type.
+ */
+ {
+ .path = dir_s2d1,
+ .access = LANDLOCK_ACCESS_FS_EXECUTE,
+ },
+ {}
+ };
+ const struct rule layer7_read_write[] = {
+ /*
+ * Finally, denies read access to file1_s1d3 via its
+ * grandparent.
+ */
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE,
+ layer1_read);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks that read access is granted for file1_s1d3 with layer 1. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDWR));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d3, O_WRONLY));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE, layer2_read_write);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks that previous access rights are unchanged with layer 2. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDWR));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d3, O_WRONLY));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE,
+ layer3_read);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks that previous access rights are unchanged with layer 3. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDWR));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d3, O_WRONLY));
+
+ /* This time, denies write access for the file hierarchy. */
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE, layer4_read_write);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Checks that the only change with layer 4 is that write access is
+ * denied.
+ */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_WRONLY));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE,
+ layer5_read);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks that previous access rights are unchanged with layer 5. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_EXECUTE,
+ layer6_execute);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks that previous access rights are unchanged with layer 6. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+
+ ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE, layer7_read_write);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks read access is now denied with layer 7. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(file2_s1d3, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, inherit_subset)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_READ_DIR,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ /* Write access is forbidden. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ /* Readdir access is allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* Write access is forbidden. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ /* Readdir access is allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /*
+ * Tests shared rule extension: the following rules should not grant
+ * any new access, only remove some. Once enforced, these rules are
+ * ANDed with the previous ones.
+ */
+ add_path_beneath(_metadata, ruleset_fd, LANDLOCK_ACCESS_FS_WRITE_FILE,
+ dir_s1d2);
+ /*
+ * According to ruleset_fd, dir_s1d2 should now have the
+ * LANDLOCK_ACCESS_FS_READ_FILE and LANDLOCK_ACCESS_FS_WRITE_FILE
+ * access rights (even if this directory is opened a second time).
+ * However, when enforcing this updated ruleset, the ruleset tied to
+ * the current process (i.e. its domain) will still only have the
+ * dir_s1d2 with LANDLOCK_ACCESS_FS_READ_FILE and
+ * LANDLOCK_ACCESS_FS_READ_DIR accesses, but
+ * LANDLOCK_ACCESS_FS_WRITE_FILE must not be allowed because it would
+ * be a privilege escalation.
+ */
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ /* Same tests and results as above. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d2. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ /* Readdir access is still allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d3. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ /* Readdir access is still allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /*
+ * Try to get more privileges by adding new access rights to the parent
+ * directory: dir_s1d1.
+ */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RW, dir_s1d1);
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ /* Same tests and results as above. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d2. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ /* Readdir access is still allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d3. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ /* Readdir access is still allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /*
+ * Now, dir_s1d3 get a new rule tied to it, only allowing
+ * LANDLOCK_ACCESS_FS_WRITE_FILE. The (kernel internal) difference is
+ * that there was no rule tied to it before.
+ */
+ add_path_beneath(_metadata, ruleset_fd, LANDLOCK_ACCESS_FS_WRITE_FILE,
+ dir_s1d3);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Same tests and results as above, except for open(dir_s1d3) which is
+ * now denied because the new rule mask the rule previously inherited
+ * from dir_s1d2.
+ */
+
+ /* Same tests and results as above. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d2. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ /* Readdir access is still allowed. */
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* It is still forbidden to write in file1_s1d3. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ /*
+ * Readdir of dir_s1d3 is still allowed because of the OR policy inside
+ * the same layer.
+ */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+}
+
+TEST_F_FORK(layout1, inherit_superset)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d3,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ /* Readdir access is denied for dir_s1d2. */
+ ASSERT_EQ(EACCES, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+ /* Readdir access is allowed for dir_s1d3. */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+ /* File access is allowed for file1_s1d3. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+
+ /* Now dir_s1d2, parent of dir_s1d3, gets a new rule tied to it. */
+ add_path_beneath(_metadata, ruleset_fd, LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_READ_DIR, dir_s1d2);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Readdir access is still denied for dir_s1d2. */
+ ASSERT_EQ(EACCES, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+ /* Readdir access is still allowed for dir_s1d3. */
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+ /* File access is still allowed for file1_s1d3. */
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, max_layers)
+{
+ int i, err;
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ for (i = 0; i < 64; i++)
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ for (i = 0; i < 2; i++) {
+ err = landlock_restrict_self(ruleset_fd, 0);
+ ASSERT_EQ(-1, err);
+ ASSERT_EQ(E2BIG, errno);
+ }
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F_FORK(layout1, empty_or_same_ruleset)
+{
+ struct landlock_ruleset_attr ruleset_attr = {};
+ int ruleset_fd;
+
+ /* Tests empty handled_access_fs. */
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(-1, ruleset_fd);
+ ASSERT_EQ(ENOMSG, errno);
+
+ /* Enforces policy which deny read access to all files. */
+ ruleset_attr.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE;
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+
+ /* Nests a policy which deny read access to all directories. */
+ ruleset_attr.handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR;
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY));
+
+ /* Enforces a second time with the same ruleset. */
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F_FORK(layout1, rule_on_mountpoint)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d1,
+ .access = ACCESS_RO,
+ },
+ {
+ /* dir_s3d2 is a mount point. */
+ .path = dir_s3d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+
+ ASSERT_EQ(EACCES, test_open(dir_s2d1, O_RDONLY));
+
+ ASSERT_EQ(EACCES, test_open(dir_s3d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d3, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, rule_over_mountpoint)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d1,
+ .access = ACCESS_RO,
+ },
+ {
+ /* dir_s3d2 is a mount point. */
+ .path = dir_s3d1,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+
+ ASSERT_EQ(EACCES, test_open(dir_s2d1, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(dir_s3d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s3d3, O_RDONLY));
+}
+
+/*
+ * This test verifies that we can apply a landlock rule on the root directory
+ * (which might require special handling).
+ */
+TEST_F_FORK(layout1, rule_over_root_allow_then_deny)
+{
+ struct rule rules[] = {
+ {
+ .path = "/",
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks allowed access. */
+ ASSERT_EQ(0, test_open("/", O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+
+ rules[0].access = LANDLOCK_ACCESS_FS_READ_FILE;
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks denied access (on a directory). */
+ ASSERT_EQ(EACCES, test_open("/", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, rule_over_root_deny)
+{
+ const struct rule rules[] = {
+ {
+ .path = "/",
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks denied access (on a directory). */
+ ASSERT_EQ(EACCES, test_open("/", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY));
+}
+
+TEST_F_FORK(layout1, rule_inside_mount_ns)
+{
+ const struct rule rules[] = {
+ {
+ .path = "s3d3",
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ int ruleset_fd;
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, syscall(SYS_pivot_root, dir_s3d2, dir_s3d3)) {
+ TH_LOG("Failed to pivot root: %s", strerror(errno));
+ };
+ ASSERT_EQ(0, chdir("/"));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, test_open("s3d3", O_RDONLY));
+ ASSERT_EQ(EACCES, test_open("/", O_RDONLY));
+}
+
+TEST_F_FORK(layout1, mount_and_pivot)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s3d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(-1, mount(NULL, dir_s3d2, NULL, MS_RDONLY, NULL));
+ ASSERT_EQ(EPERM, errno);
+ ASSERT_EQ(-1, syscall(SYS_pivot_root, dir_s3d2, dir_s3d3));
+ ASSERT_EQ(EPERM, errno);
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+TEST_F_FORK(layout1, move_mount)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s3d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, syscall(SYS_move_mount, AT_FDCWD, dir_s3d2, AT_FDCWD,
+ dir_s1d2, 0)) {
+ TH_LOG("Failed to move mount: %s", strerror(errno));
+ }
+
+ ASSERT_EQ(0, syscall(SYS_move_mount, AT_FDCWD, dir_s1d2, AT_FDCWD,
+ dir_s3d2, 0));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(-1, syscall(SYS_move_mount, AT_FDCWD, dir_s3d2, AT_FDCWD,
+ dir_s1d2, 0));
+ ASSERT_EQ(EPERM, errno);
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+TEST_F_FORK(layout1, release_inodes)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d1,
+ .access = ACCESS_RO,
+ },
+ {
+ .path = dir_s3d2,
+ .access = ACCESS_RO,
+ },
+ {
+ .path = dir_s3d3,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ /* Unmount a file hierarchy while it is being used by a ruleset. */
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, umount(dir_s3d2));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s3d2, O_RDONLY));
+ /* This dir_s3d3 would not be allowed and does not exist anyway. */
+ ASSERT_EQ(ENOENT, test_open(dir_s3d3, O_RDONLY));
+}
+
+enum relative_access {
+ REL_OPEN,
+ REL_CHDIR,
+ REL_CHROOT_ONLY,
+ REL_CHROOT_CHDIR,
+};
+
+static void test_relative_path(struct __test_metadata *const _metadata,
+ const enum relative_access rel)
+{
+ /*
+ * Common layer to check that chroot doesn't ignore it (i.e. a chroot
+ * is not a disconnected root directory).
+ */
+ const struct rule layer1_base[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ const struct rule layer2_subs[] = {
+ {
+ .path = dir_s1d2,
+ .access = ACCESS_RO,
+ },
+ {
+ .path = dir_s2d2,
+ .access = ACCESS_RO,
+ },
+ {}
+ };
+ int dirfd, ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer1_base);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer2_subs);
+
+ ASSERT_LE(0, ruleset_fd);
+ switch (rel) {
+ case REL_OPEN:
+ case REL_CHDIR:
+ break;
+ case REL_CHROOT_ONLY:
+ ASSERT_EQ(0, chdir(dir_s2d2));
+ break;
+ case REL_CHROOT_CHDIR:
+ ASSERT_EQ(0, chdir(dir_s1d2));
+ break;
+ default:
+ ASSERT_TRUE(false);
+ return;
+ }
+
+ set_cap(_metadata, CAP_SYS_CHROOT);
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ switch (rel) {
+ case REL_OPEN:
+ dirfd = open(dir_s1d2, O_DIRECTORY);
+ ASSERT_LE(0, dirfd);
+ break;
+ case REL_CHDIR:
+ ASSERT_EQ(0, chdir(dir_s1d2));
+ dirfd = AT_FDCWD;
+ break;
+ case REL_CHROOT_ONLY:
+ /* Do chroot into dir_s1d2 (relative to dir_s2d2). */
+ ASSERT_EQ(0, chroot("../../s1d1/s1d2")) {
+ TH_LOG("Failed to chroot: %s", strerror(errno));
+ }
+ dirfd = AT_FDCWD;
+ break;
+ case REL_CHROOT_CHDIR:
+ /* Do chroot into dir_s1d2. */
+ ASSERT_EQ(0, chroot(".")) {
+ TH_LOG("Failed to chroot: %s", strerror(errno));
+ }
+ dirfd = AT_FDCWD;
+ break;
+ }
+
+ ASSERT_EQ((rel == REL_CHROOT_CHDIR) ? 0 : EACCES,
+ test_open_rel(dirfd, "..", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, ".", O_RDONLY));
+
+ if (rel == REL_CHROOT_ONLY) {
+ /* The current directory is dir_s2d2. */
+ ASSERT_EQ(0, test_open_rel(dirfd, "./s2d3", O_RDONLY));
+ } else {
+ /* The current directory is dir_s1d2. */
+ ASSERT_EQ(0, test_open_rel(dirfd, "./s1d3", O_RDONLY));
+ }
+
+ if (rel == REL_CHROOT_ONLY || rel == REL_CHROOT_CHDIR) {
+ /* Checks the root dir_s1d2. */
+ ASSERT_EQ(0, test_open_rel(dirfd, "/..", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "/", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "/f1", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "/s1d3", O_RDONLY));
+ }
+
+ if (rel != REL_CHROOT_CHDIR) {
+ ASSERT_EQ(EACCES, test_open_rel(dirfd, "../../s1d1", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "../../s1d1/s1d2", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "../../s1d1/s1d2/s1d3", O_RDONLY));
+
+ ASSERT_EQ(EACCES, test_open_rel(dirfd, "../../s2d1", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "../../s2d1/s2d2", O_RDONLY));
+ ASSERT_EQ(0, test_open_rel(dirfd, "../../s2d1/s2d2/s2d3", O_RDONLY));
+ }
+
+ if (rel == REL_OPEN)
+ ASSERT_EQ(0, close(dirfd));
+ ASSERT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F_FORK(layout1, relative_open)
+{
+ test_relative_path(_metadata, REL_OPEN);
+}
+
+TEST_F_FORK(layout1, relative_chdir)
+{
+ test_relative_path(_metadata, REL_CHDIR);
+}
+
+TEST_F_FORK(layout1, relative_chroot_only)
+{
+ test_relative_path(_metadata, REL_CHROOT_ONLY);
+}
+
+TEST_F_FORK(layout1, relative_chroot_chdir)
+{
+ test_relative_path(_metadata, REL_CHROOT_CHDIR);
+}
+
+static void copy_binary(struct __test_metadata *const _metadata,
+ const char *const dst_path)
+{
+ int dst_fd, src_fd;
+ struct stat statbuf;
+
+ dst_fd = open(dst_path, O_WRONLY | O_TRUNC | O_CLOEXEC);
+ ASSERT_LE(0, dst_fd) {
+ TH_LOG("Failed to open \"%s\": %s", dst_path,
+ strerror(errno));
+ }
+ src_fd = open(BINARY_PATH, O_RDONLY | O_CLOEXEC);
+ ASSERT_LE(0, src_fd) {
+ TH_LOG("Failed to open \"" BINARY_PATH "\": %s",
+ strerror(errno));
+ }
+ ASSERT_EQ(0, fstat(src_fd, &statbuf));
+ ASSERT_EQ(statbuf.st_size, sendfile(dst_fd, src_fd, 0,
+ statbuf.st_size));
+ ASSERT_EQ(0, close(src_fd));
+ ASSERT_EQ(0, close(dst_fd));
+}
+
+static void test_execute(struct __test_metadata *const _metadata,
+ const int err, const char *const path)
+{
+ int status;
+ char *const argv[] = {(char *)path, NULL};
+ const pid_t child = fork();
+
+ ASSERT_LE(0, child);
+ if (child == 0) {
+ ASSERT_EQ(err ? -1 : 0, execve(path, argv, NULL)) {
+ TH_LOG("Failed to execute \"%s\": %s", path,
+ strerror(errno));
+ };
+ ASSERT_EQ(err, errno);
+ _exit(_metadata->passed ? 2 : 1);
+ return;
+ }
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFEXITED(status));
+ ASSERT_EQ(err ? 2 : 0, WEXITSTATUS(status)) {
+ TH_LOG("Unexpected return code for \"%s\": %s", path,
+ strerror(errno));
+ };
+}
+
+TEST_F_FORK(layout1, execute)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_EXECUTE,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ copy_binary(_metadata, file1_s1d1);
+ copy_binary(_metadata, file1_s1d2);
+ copy_binary(_metadata, file1_s1d3);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
+ test_execute(_metadata, EACCES, file1_s1d1);
+
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ test_execute(_metadata, 0, file1_s1d2);
+
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ test_execute(_metadata, 0, file1_s1d3);
+}
+
+TEST_F_FORK(layout1, link)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_MAKE_REG,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlink(file1_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, link(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ /* Denies linking because of reparenting. */
+ ASSERT_EQ(-1, link(file1_s2d1, file1_s1d2));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, link(file2_s1d2, file1_s1d3));
+ ASSERT_EQ(EXDEV, errno);
+
+ ASSERT_EQ(0, link(file2_s1d2, file1_s1d2));
+ ASSERT_EQ(0, link(file2_s1d3, file1_s1d3));
+}
+
+TEST_F_FORK(layout1, rename_file)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d3,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {
+ .path = dir_s2d2,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Tries to replace a file, from a directory that allows file removal,
+ * but to a different directory (which also allows file removal).
+ */
+ ASSERT_EQ(-1, rename(file1_s2d3, file1_s1d3));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d3, AT_FDCWD, file1_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d3, AT_FDCWD, dir_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+
+ /*
+ * Tries to replace a file, from a directory that denies file removal,
+ * to a different directory (which allows file removal).
+ */
+ ASSERT_EQ(-1, rename(file1_s2d1, file1_s1d3));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d1, AT_FDCWD, file1_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s2d2, AT_FDCWD, file1_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+
+ /* Exchanges files and directories that partially allow removal. */
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s2d2, AT_FDCWD, file1_s2d1,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d1, AT_FDCWD, dir_s2d2,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EACCES, errno);
+
+ /* Renames files with different parents. */
+ ASSERT_EQ(-1, rename(file1_s2d2, file1_s1d2));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(-1, rename(file1_s2d1, file1_s1d3));
+ ASSERT_EQ(EXDEV, errno);
+
+ /* Exchanges and renames files with same parent. */
+ ASSERT_EQ(0, renameat2(AT_FDCWD, file2_s2d3, AT_FDCWD, file1_s2d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(0, rename(file2_s2d3, file1_s2d3));
+
+ /* Exchanges files and directories with same parent, twice. */
+ ASSERT_EQ(0, renameat2(AT_FDCWD, file1_s2d2, AT_FDCWD, dir_s2d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(0, renameat2(AT_FDCWD, file1_s2d2, AT_FDCWD, dir_s2d3,
+ RENAME_EXCHANGE));
+}
+
+TEST_F_FORK(layout1, rename_dir)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ },
+ {
+ .path = dir_s2d1,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Empties dir_s1d3 to allow renaming. */
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Exchanges and renames directory to a different parent. */
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s2d3, AT_FDCWD, dir_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, rename(dir_s2d3, dir_s1d3));
+ ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d2, AT_FDCWD, dir_s1d3,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EXDEV, errno);
+
+ /*
+ * Exchanges directory to the same parent, which doesn't allow
+ * directory removal.
+ */
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s1d1, AT_FDCWD, dir_s2d1,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s1d1, AT_FDCWD, dir_s1d2,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Exchanges and renames directory to the same parent, which allows
+ * directory removal.
+ */
+ ASSERT_EQ(0, renameat2(AT_FDCWD, dir_s1d3, AT_FDCWD, file1_s1d2,
+ RENAME_EXCHANGE));
+ ASSERT_EQ(0, unlink(dir_s1d3));
+ ASSERT_EQ(0, mkdir(dir_s1d3, 0700));
+ ASSERT_EQ(0, rename(file1_s1d2, dir_s1d3));
+ ASSERT_EQ(0, rmdir(dir_s1d3));
+}
+
+TEST_F_FORK(layout1, remove_dir)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, rmdir(dir_s1d3));
+ ASSERT_EQ(0, mkdir(dir_s1d3, 0700));
+ ASSERT_EQ(0, unlinkat(AT_FDCWD, dir_s1d3, AT_REMOVEDIR));
+
+ /* dir_s1d2 itself cannot be removed. */
+ ASSERT_EQ(-1, rmdir(dir_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, unlinkat(AT_FDCWD, dir_s1d2, AT_REMOVEDIR));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rmdir(dir_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, unlinkat(AT_FDCWD, dir_s1d1, AT_REMOVEDIR));
+ ASSERT_EQ(EACCES, errno);
+}
+
+TEST_F_FORK(layout1, remove_file)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, unlink(file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, unlinkat(AT_FDCWD, file1_s1d1, 0));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlinkat(AT_FDCWD, file1_s1d3, 0));
+}
+
+static void test_make_file(struct __test_metadata *const _metadata,
+ const __u64 access, const mode_t mode, const dev_t dev)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = access,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, access, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file2_s1d1));
+ ASSERT_EQ(0, mknod(file2_s1d1, mode | 0400, dev)) {
+ TH_LOG("Failed to make file \"%s\": %s",
+ file2_s1d1, strerror(errno));
+ };
+
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlink(file2_s1d2));
+
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, mknod(file1_s1d1, mode | 0400, dev));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, link(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+
+ ASSERT_EQ(0, mknod(file1_s1d2, mode | 0400, dev)) {
+ TH_LOG("Failed to make file \"%s\": %s",
+ file1_s1d2, strerror(errno));
+ };
+ ASSERT_EQ(0, link(file1_s1d2, file2_s1d2));
+ ASSERT_EQ(0, unlink(file2_s1d2));
+ ASSERT_EQ(0, rename(file1_s1d2, file2_s1d2));
+
+ ASSERT_EQ(0, mknod(file1_s1d3, mode | 0400, dev));
+ ASSERT_EQ(0, link(file1_s1d3, file2_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+ ASSERT_EQ(0, rename(file1_s1d3, file2_s1d3));
+}
+
+TEST_F_FORK(layout1, make_char)
+{
+ /* Creates a /dev/null device. */
+ set_cap(_metadata, CAP_MKNOD);
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_CHAR, S_IFCHR,
+ makedev(1, 3));
+}
+
+TEST_F_FORK(layout1, make_block)
+{
+ /* Creates a /dev/loop0 device. */
+ set_cap(_metadata, CAP_MKNOD);
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_BLOCK, S_IFBLK,
+ makedev(7, 0));
+}
+
+TEST_F_FORK(layout1, make_reg_1)
+{
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_REG, S_IFREG, 0);
+}
+
+TEST_F_FORK(layout1, make_reg_2)
+{
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_REG, 0, 0);
+}
+
+TEST_F_FORK(layout1, make_sock)
+{
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_SOCK, S_IFSOCK, 0);
+}
+
+TEST_F_FORK(layout1, make_fifo)
+{
+ test_make_file(_metadata, LANDLOCK_ACCESS_FS_MAKE_FIFO, S_IFIFO, 0);
+}
+
+TEST_F_FORK(layout1, make_sym)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_MAKE_SYM,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file2_s1d1));
+ ASSERT_EQ(0, symlink("none", file2_s1d1));
+
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlink(file2_s1d2));
+
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, symlink("none", file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, link(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(EACCES, errno);
+
+ ASSERT_EQ(0, symlink("none", file1_s1d2));
+ ASSERT_EQ(0, link(file1_s1d2, file2_s1d2));
+ ASSERT_EQ(0, unlink(file2_s1d2));
+ ASSERT_EQ(0, rename(file1_s1d2, file2_s1d2));
+
+ ASSERT_EQ(0, symlink("none", file1_s1d3));
+ ASSERT_EQ(0, link(file1_s1d3, file2_s1d3));
+ ASSERT_EQ(0, unlink(file2_s1d3));
+ ASSERT_EQ(0, rename(file1_s1d3, file2_s1d3));
+}
+
+TEST_F_FORK(layout1, make_dir)
+{
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_MAKE_DIR,
+ },
+ {}
+ };
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ ASSERT_EQ(0, unlink(file1_s1d3));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Uses file_* as directory names. */
+ ASSERT_EQ(-1, mkdir(file1_s1d1, 0700));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(0, mkdir(file1_s1d2, 0700));
+ ASSERT_EQ(0, mkdir(file1_s1d3, 0700));
+}
+
+static int open_proc_fd(struct __test_metadata *const _metadata, const int fd,
+ const int open_flags)
+{
+ static const char path_template[] = "/proc/self/fd/%d";
+ char procfd_path[sizeof(path_template) + 10];
+ const int procfd_path_size = snprintf(procfd_path, sizeof(procfd_path),
+ path_template, fd);
+
+ ASSERT_LT(procfd_path_size, sizeof(procfd_path));
+ return open(procfd_path, open_flags);
+}
+
+TEST_F_FORK(layout1, proc_unlinked_file)
+{
+ const struct rule rules[] = {
+ {
+ .path = file1_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ int reg_fd, proc_fd;
+ const int ruleset_fd = create_ruleset(_metadata,
+ LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE, rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_RDWR));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ reg_fd = open(file1_s1d2, O_RDONLY | O_CLOEXEC);
+ ASSERT_LE(0, reg_fd);
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ proc_fd = open_proc_fd(_metadata, reg_fd, O_RDONLY | O_CLOEXEC);
+ ASSERT_LE(0, proc_fd);
+ ASSERT_EQ(0, close(proc_fd));
+
+ proc_fd = open_proc_fd(_metadata, reg_fd, O_RDWR | O_CLOEXEC);
+ ASSERT_EQ(-1, proc_fd) {
+ TH_LOG("Successfully opened /proc/self/fd/%d: %s",
+ reg_fd, strerror(errno));
+ }
+ ASSERT_EQ(EACCES, errno);
+
+ ASSERT_EQ(0, close(reg_fd));
+}
+
+TEST_F_FORK(layout1, proc_pipe)
+{
+ int proc_fd;
+ int pipe_fds[2];
+ char buf = '\0';
+ const struct rule rules[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ /* Limits read and write access to files tied to the filesystem. */
+ const int ruleset_fd = create_ruleset(_metadata, rules[0].access,
+ rules);
+
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks enforcement for normal files. */
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDWR));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDWR));
+
+ /* Checks access to pipes through FD. */
+ ASSERT_EQ(0, pipe2(pipe_fds, O_CLOEXEC));
+ ASSERT_EQ(1, write(pipe_fds[1], ".", 1)) {
+ TH_LOG("Failed to write in pipe: %s", strerror(errno));
+ }
+ ASSERT_EQ(1, read(pipe_fds[0], &buf, 1));
+ ASSERT_EQ('.', buf);
+
+ /* Checks write access to pipe through /proc/self/fd . */
+ proc_fd = open_proc_fd(_metadata, pipe_fds[1], O_WRONLY | O_CLOEXEC);
+ ASSERT_LE(0, proc_fd);
+ ASSERT_EQ(1, write(proc_fd, ".", 1)) {
+ TH_LOG("Failed to write through /proc/self/fd/%d: %s",
+ pipe_fds[1], strerror(errno));
+ }
+ ASSERT_EQ(0, close(proc_fd));
+
+ /* Checks read access to pipe through /proc/self/fd . */
+ proc_fd = open_proc_fd(_metadata, pipe_fds[0], O_RDONLY | O_CLOEXEC);
+ ASSERT_LE(0, proc_fd);
+ buf = '\0';
+ ASSERT_EQ(1, read(proc_fd, &buf, 1)) {
+ TH_LOG("Failed to read through /proc/self/fd/%d: %s",
+ pipe_fds[1], strerror(errno));
+ }
+ ASSERT_EQ(0, close(proc_fd));
+
+ ASSERT_EQ(0, close(pipe_fds[0]));
+ ASSERT_EQ(0, close(pipe_fds[1]));
+}
+
+FIXTURE(layout1_bind) {
+};
+
+FIXTURE_SETUP(layout1_bind)
+{
+ prepare_layout(_metadata);
+
+ create_layout1(_metadata);
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, mount(dir_s1d2, dir_s2d2, NULL, MS_BIND, NULL));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+FIXTURE_TEARDOWN(layout1_bind)
+{
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, umount(dir_s2d2));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+
+ remove_layout1(_metadata);
+
+ cleanup_layout(_metadata);
+}
+
+static const char bind_dir_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3";
+static const char bind_file1_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3/f1";
+
+/*
+ * layout1_bind hierarchy:
+ *
+ * tmp
+ * ├── s1d1
+ * │ ├── f1
+ * │ ├── f2
+ * │ └── s1d2
+ * │ ├── f1
+ * │ ├── f2
+ * │ └── s1d3
+ * │ ├── f1
+ * │ └── f2
+ * ├── s2d1
+ * │ ├── f1
+ * │ └── s2d2
+ * │ ├── f1
+ * │ ├── f2
+ * │ └── s1d3
+ * │ ├── f1
+ * │ └── f2
+ * └── s3d1
+ * └── s3d2
+ * └── s3d3
+ */
+
+TEST_F_FORK(layout1_bind, no_restriction)
+{
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(dir_s2d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d1, O_RDONLY));
+ ASSERT_EQ(0, test_open(dir_s2d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file1_s2d2, O_RDONLY));
+ ASSERT_EQ(ENOENT, test_open(dir_s2d3, O_RDONLY));
+ ASSERT_EQ(ENOENT, test_open(file1_s2d3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(bind_dir_s1d3, O_RDONLY));
+ ASSERT_EQ(0, test_open(bind_file1_s1d3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(dir_s3d1, O_RDONLY));
+}
+
+TEST_F_FORK(layout1_bind, same_content_same_file)
+{
+ /*
+ * Sets access right on parent directories of both source and
+ * destination mount points.
+ */
+ const struct rule layer1_parent[] = {
+ {
+ .path = dir_s1d1,
+ .access = ACCESS_RO,
+ },
+ {
+ .path = dir_s2d1,
+ .access = ACCESS_RW,
+ },
+ {}
+ };
+ /*
+ * Sets access rights on the same bind-mounted directories. The result
+ * should be ACCESS_RW for both directories, but not both hierarchies
+ * because of the first layer.
+ */
+ const struct rule layer2_mount_point[] = {
+ {
+ .path = dir_s1d2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = dir_s2d2,
+ .access = ACCESS_RW,
+ },
+ {}
+ };
+ /* Only allow read-access to the s1d3 hierarchies. */
+ const struct rule layer3_source[] = {
+ {
+ .path = dir_s1d3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {}
+ };
+ /* Removes all access rights. */
+ const struct rule layer4_destination[] = {
+ {
+ .path = bind_file1_s1d3,
+ .access = LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ int ruleset_fd;
+
+ /* Sets rules for the parent directories. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer1_parent);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks source hierarchy. */
+ ASSERT_EQ(0, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(0, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* Checks destination hierarchy. */
+ ASSERT_EQ(0, test_open(file1_s2d1, O_RDWR));
+ ASSERT_EQ(0, test_open(dir_s2d1, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(file1_s2d2, O_RDWR));
+ ASSERT_EQ(0, test_open(dir_s2d2, O_RDONLY | O_DIRECTORY));
+
+ /* Sets rules for the mount points. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer2_mount_point);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks source hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ /* Checks destination hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s2d1, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s2d1, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s2d1, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(file1_s2d2, O_RDWR));
+ ASSERT_EQ(0, test_open(dir_s2d2, O_RDONLY | O_DIRECTORY));
+ ASSERT_EQ(0, test_open(bind_dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /* Sets a (shared) rule only on the source. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer3_source);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks source hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /* Checks destination hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s2d2, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s2d2, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(dir_s2d2, O_RDONLY | O_DIRECTORY));
+
+ ASSERT_EQ(0, test_open(bind_file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(bind_file1_s1d3, O_WRONLY));
+ ASSERT_EQ(EACCES, test_open(bind_dir_s1d3, O_RDONLY | O_DIRECTORY));
+
+ /* Sets a (shared) rule only on the destination. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer4_destination);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks source hierarchy. */
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+
+ /* Checks destination hierarchy. */
+ ASSERT_EQ(EACCES, test_open(bind_file1_s1d3, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(bind_file1_s1d3, O_WRONLY));
+}
+
+#define LOWER_BASE TMP_DIR "/lower"
+#define LOWER_DATA LOWER_BASE "/data"
+static const char lower_fl1[] = LOWER_DATA "/fl1";
+static const char lower_dl1[] = LOWER_DATA "/dl1";
+static const char lower_dl1_fl2[] = LOWER_DATA "/dl1/fl2";
+static const char lower_fo1[] = LOWER_DATA "/fo1";
+static const char lower_do1[] = LOWER_DATA "/do1";
+static const char lower_do1_fo2[] = LOWER_DATA "/do1/fo2";
+static const char lower_do1_fl3[] = LOWER_DATA "/do1/fl3";
+
+static const char (*lower_base_files[])[] = {
+ &lower_fl1,
+ &lower_fo1,
+ NULL
+};
+static const char (*lower_base_directories[])[] = {
+ &lower_dl1,
+ &lower_do1,
+ NULL
+};
+static const char (*lower_sub_files[])[] = {
+ &lower_dl1_fl2,
+ &lower_do1_fo2,
+ &lower_do1_fl3,
+ NULL
+};
+
+#define UPPER_BASE TMP_DIR "/upper"
+#define UPPER_DATA UPPER_BASE "/data"
+#define UPPER_WORK UPPER_BASE "/work"
+static const char upper_fu1[] = UPPER_DATA "/fu1";
+static const char upper_du1[] = UPPER_DATA "/du1";
+static const char upper_du1_fu2[] = UPPER_DATA "/du1/fu2";
+static const char upper_fo1[] = UPPER_DATA "/fo1";
+static const char upper_do1[] = UPPER_DATA "/do1";
+static const char upper_do1_fo2[] = UPPER_DATA "/do1/fo2";
+static const char upper_do1_fu3[] = UPPER_DATA "/do1/fu3";
+
+static const char (*upper_base_files[])[] = {
+ &upper_fu1,
+ &upper_fo1,
+ NULL
+};
+static const char (*upper_base_directories[])[] = {
+ &upper_du1,
+ &upper_do1,
+ NULL
+};
+static const char (*upper_sub_files[])[] = {
+ &upper_du1_fu2,
+ &upper_do1_fo2,
+ &upper_do1_fu3,
+ NULL
+};
+
+#define MERGE_BASE TMP_DIR "/merge"
+#define MERGE_DATA MERGE_BASE "/data"
+static const char merge_fl1[] = MERGE_DATA "/fl1";
+static const char merge_dl1[] = MERGE_DATA "/dl1";
+static const char merge_dl1_fl2[] = MERGE_DATA "/dl1/fl2";
+static const char merge_fu1[] = MERGE_DATA "/fu1";
+static const char merge_du1[] = MERGE_DATA "/du1";
+static const char merge_du1_fu2[] = MERGE_DATA "/du1/fu2";
+static const char merge_fo1[] = MERGE_DATA "/fo1";
+static const char merge_do1[] = MERGE_DATA "/do1";
+static const char merge_do1_fo2[] = MERGE_DATA "/do1/fo2";
+static const char merge_do1_fl3[] = MERGE_DATA "/do1/fl3";
+static const char merge_do1_fu3[] = MERGE_DATA "/do1/fu3";
+
+static const char (*merge_base_files[])[] = {
+ &merge_fl1,
+ &merge_fu1,
+ &merge_fo1,
+ NULL
+};
+static const char (*merge_base_directories[])[] = {
+ &merge_dl1,
+ &merge_du1,
+ &merge_do1,
+ NULL
+};
+static const char (*merge_sub_files[])[] = {
+ &merge_dl1_fl2,
+ &merge_du1_fu2,
+ &merge_do1_fo2,
+ &merge_do1_fl3,
+ &merge_do1_fu3,
+ NULL
+};
+
+/*
+ * layout2_overlay hierarchy:
+ *
+ * tmp
+ * ├── lower
+ * │ └── data
+ * │ ├── dl1
+ * │ │ └── fl2
+ * │ ├── do1
+ * │ │ ├── fl3
+ * │ │ └── fo2
+ * │ ├── fl1
+ * │ └── fo1
+ * ├── merge
+ * │ └── data
+ * │ ├── dl1
+ * │ │ └── fl2
+ * │ ├── do1
+ * │ │ ├── fl3
+ * │ │ ├── fo2
+ * │ │ └── fu3
+ * │ ├── du1
+ * │ │ └── fu2
+ * │ ├── fl1
+ * │ ├── fo1
+ * │ └── fu1
+ * └── upper
+ * ├── data
+ * │ ├── do1
+ * │ │ ├── fo2
+ * │ │ └── fu3
+ * │ ├── du1
+ * │ │ └── fu2
+ * │ ├── fo1
+ * │ └── fu1
+ * └── work
+ * └── work
+ */
+
+FIXTURE(layout2_overlay) {
+};
+
+FIXTURE_SETUP(layout2_overlay)
+{
+ prepare_layout(_metadata);
+
+ create_directory(_metadata, LOWER_BASE);
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ /* Creates tmpfs mount points to get deterministic overlayfs. */
+ ASSERT_EQ(0, mount("tmp", LOWER_BASE, "tmpfs", 0, "size=4m,mode=700"));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ create_file(_metadata, lower_fl1);
+ create_file(_metadata, lower_dl1_fl2);
+ create_file(_metadata, lower_fo1);
+ create_file(_metadata, lower_do1_fo2);
+ create_file(_metadata, lower_do1_fl3);
+
+ create_directory(_metadata, UPPER_BASE);
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ ASSERT_EQ(0, mount("tmp", UPPER_BASE, "tmpfs", 0, "size=4m,mode=700"));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ create_file(_metadata, upper_fu1);
+ create_file(_metadata, upper_du1_fu2);
+ create_file(_metadata, upper_fo1);
+ create_file(_metadata, upper_do1_fo2);
+ create_file(_metadata, upper_do1_fu3);
+ ASSERT_EQ(0, mkdir(UPPER_WORK, 0700));
+
+ create_directory(_metadata, MERGE_DATA);
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ set_cap(_metadata, CAP_DAC_OVERRIDE);
+ ASSERT_EQ(0, mount("overlay", MERGE_DATA, "overlay", 0,
+ "lowerdir=" LOWER_DATA
+ ",upperdir=" UPPER_DATA
+ ",workdir=" UPPER_WORK));
+ clear_cap(_metadata, CAP_DAC_OVERRIDE);
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+FIXTURE_TEARDOWN(layout2_overlay)
+{
+ EXPECT_EQ(0, remove_path(lower_do1_fl3));
+ EXPECT_EQ(0, remove_path(lower_dl1_fl2));
+ EXPECT_EQ(0, remove_path(lower_fl1));
+ EXPECT_EQ(0, remove_path(lower_do1_fo2));
+ EXPECT_EQ(0, remove_path(lower_fo1));
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, umount(LOWER_BASE));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, remove_path(LOWER_BASE));
+
+ EXPECT_EQ(0, remove_path(upper_do1_fu3));
+ EXPECT_EQ(0, remove_path(upper_du1_fu2));
+ EXPECT_EQ(0, remove_path(upper_fu1));
+ EXPECT_EQ(0, remove_path(upper_do1_fo2));
+ EXPECT_EQ(0, remove_path(upper_fo1));
+ EXPECT_EQ(0, remove_path(UPPER_WORK "/work"));
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, umount(UPPER_BASE));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, remove_path(UPPER_BASE));
+
+ set_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, umount(MERGE_DATA));
+ clear_cap(_metadata, CAP_SYS_ADMIN);
+ EXPECT_EQ(0, remove_path(MERGE_DATA));
+
+ cleanup_layout(_metadata);
+}
+
+TEST_F_FORK(layout2_overlay, no_restriction)
+{
+ ASSERT_EQ(0, test_open(lower_fl1, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_dl1, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_dl1_fl2, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_fo1, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_do1, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_do1_fo2, O_RDONLY));
+ ASSERT_EQ(0, test_open(lower_do1_fl3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(upper_fu1, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_du1, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_du1_fu2, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_fo1, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_do1, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_do1_fo2, O_RDONLY));
+ ASSERT_EQ(0, test_open(upper_do1_fu3, O_RDONLY));
+
+ ASSERT_EQ(0, test_open(merge_fl1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_dl1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_dl1_fl2, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_fu1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_du1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_du1_fu2, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_fo1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_do1, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_do1_fo2, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_do1_fl3, O_RDONLY));
+ ASSERT_EQ(0, test_open(merge_do1_fu3, O_RDONLY));
+}
+
+#define for_each_path(path_list, path_entry, i) \
+ for (i = 0, path_entry = *path_list[i]; path_list[i]; \
+ path_entry = *path_list[++i])
+
+TEST_F_FORK(layout2_overlay, same_content_different_file)
+{
+ /* Sets access right on parent directories of both layers. */
+ const struct rule layer1_base[] = {
+ {
+ .path = LOWER_BASE,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = UPPER_BASE,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = MERGE_BASE,
+ .access = ACCESS_RW,
+ },
+ {}
+ };
+ const struct rule layer2_data[] = {
+ {
+ .path = LOWER_DATA,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = UPPER_DATA,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = MERGE_DATA,
+ .access = ACCESS_RW,
+ },
+ {}
+ };
+ /* Sets access right on directories inside both layers. */
+ const struct rule layer3_subdirs[] = {
+ {
+ .path = lower_dl1,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = lower_do1,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = upper_du1,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = upper_do1,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = merge_dl1,
+ .access = ACCESS_RW,
+ },
+ {
+ .path = merge_du1,
+ .access = ACCESS_RW,
+ },
+ {
+ .path = merge_do1,
+ .access = ACCESS_RW,
+ },
+ {}
+ };
+ /* Tighten access rights to the files. */
+ const struct rule layer4_files[] = {
+ {
+ .path = lower_dl1_fl2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = lower_do1_fo2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = lower_do1_fl3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = upper_du1_fu2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = upper_do1_fo2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = upper_do1_fu3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE,
+ },
+ {
+ .path = merge_dl1_fl2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {
+ .path = merge_du1_fu2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {
+ .path = merge_do1_fo2,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {
+ .path = merge_do1_fl3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {
+ .path = merge_do1_fu3,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ const struct rule layer5_merge_only[] = {
+ {
+ .path = MERGE_DATA,
+ .access = LANDLOCK_ACCESS_FS_READ_FILE |
+ LANDLOCK_ACCESS_FS_WRITE_FILE,
+ },
+ {}
+ };
+ int ruleset_fd;
+ size_t i;
+ const char *path_entry;
+
+ /* Sets rules on base directories (i.e. outside overlay scope). */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer1_base);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks lower layer. */
+ for_each_path(lower_base_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ for_each_path(lower_base_directories, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(lower_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ /* Checks upper layer. */
+ for_each_path(upper_base_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ for_each_path(upper_base_directories, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(upper_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ /*
+ * Checks that access rights are independent from the lower and upper
+ * layers: write access to upper files viewed through the merge point
+ * is still allowed, and write access to lower file viewed (and copied)
+ * through the merge point is still allowed.
+ */
+ for_each_path(merge_base_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+ for_each_path(merge_base_directories, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(merge_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+
+ /* Sets rules on data directories (i.e. inside overlay scope). */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer2_data);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks merge. */
+ for_each_path(merge_base_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+ for_each_path(merge_base_directories, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(merge_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+
+ /* Same checks with tighter rules. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer3_subdirs);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks changes for lower layer. */
+ for_each_path(lower_base_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY));
+ }
+ /* Checks changes for upper layer. */
+ for_each_path(upper_base_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY));
+ }
+ /* Checks all merge accesses. */
+ for_each_path(merge_base_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDWR));
+ }
+ for_each_path(merge_base_directories, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(merge_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+
+ /* Sets rules directly on overlayed files. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer4_files);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks unchanged accesses on lower layer. */
+ for_each_path(lower_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ /* Checks unchanged accesses on upper layer. */
+ for_each_path(upper_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(path_entry, O_WRONLY));
+ }
+ /* Checks all merge accesses. */
+ for_each_path(merge_base_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDWR));
+ }
+ for_each_path(merge_base_directories, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(merge_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+
+ /* Only allowes access to the merge hierarchy. */
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, layer5_merge_only);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Checks new accesses on lower layer. */
+ for_each_path(lower_sub_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY));
+ }
+ /* Checks new accesses on upper layer. */
+ for_each_path(upper_sub_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY));
+ }
+ /* Checks all merge accesses. */
+ for_each_path(merge_base_files, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDWR));
+ }
+ for_each_path(merge_base_directories, path_entry, i) {
+ ASSERT_EQ(EACCES, test_open(path_entry, O_RDONLY | O_DIRECTORY));
+ }
+ for_each_path(merge_sub_files, path_entry, i) {
+ ASSERT_EQ(0, test_open(path_entry, O_RDWR));
+ }
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/landlock/ptrace_test.c b/tools/testing/selftests/landlock/ptrace_test.c
new file mode 100644
index 000000000000..15fbef9cc849
--- /dev/null
+++ b/tools/testing/selftests/landlock/ptrace_test.c
@@ -0,0 +1,337 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Landlock tests - Ptrace
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <[email protected]>
+ * Copyright © 2019-2020 ANSSI
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "common.h"
+
+static void create_domain(struct __test_metadata *const _metadata)
+{
+ int ruleset_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_MAKE_BLOCK,
+ };
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ EXPECT_LE(0, ruleset_fd) {
+ TH_LOG("Failed to create a ruleset: %s", strerror(errno));
+ }
+ EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+ EXPECT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
+ EXPECT_EQ(0, close(ruleset_fd));
+}
+
+static int test_ptrace_read(const pid_t pid)
+{
+ static const char path_template[] = "/proc/%d/environ";
+ char procenv_path[sizeof(path_template) + 10];
+ int procenv_path_size, fd;
+
+ procenv_path_size = snprintf(procenv_path, sizeof(procenv_path),
+ path_template, pid);
+ if (procenv_path_size >= sizeof(procenv_path))
+ return E2BIG;
+
+ fd = open(procenv_path, O_RDONLY | O_CLOEXEC);
+ if (fd < 0)
+ return errno;
+ /*
+ * Mixing error codes from close(2) and open(2) should not lead to any
+ * (access type) confusion for this test.
+ */
+ if (close(fd) != 0)
+ return errno;
+ return 0;
+}
+
+FIXTURE(hierarchy) { };
+
+FIXTURE_VARIANT(hierarchy) {
+ const bool domain_both;
+ const bool domain_parent;
+ const bool domain_child;
+};
+
+/*
+ * Test multiple tracing combinations between a parent process P1 and a child
+ * process P2.
+ *
+ * Yama's scoped ptrace is presumed disabled. If enabled, this optional
+ * restriction is enforced in addition to any Landlock check, which means that
+ * all P2 requests to trace P1 would be denied.
+ */
+
+/*
+ * No domain
+ *
+ * P1-. P1 -> P2 : allow
+ * \ P2 -> P1 : allow
+ * 'P2
+ */
+FIXTURE_VARIANT_ADD(hierarchy, allow_without_domain) {
+ .domain_both = false,
+ .domain_parent = false,
+ .domain_child = false,
+};
+
+/*
+ * Child domain
+ *
+ * P1--. P1 -> P2 : allow
+ * \ P2 -> P1 : deny
+ * .'-----.
+ * | P2 |
+ * '------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, allow_with_one_domain) {
+ .domain_both = false,
+ .domain_parent = false,
+ .domain_child = true,
+};
+
+/*
+ * Parent domain
+ * .------.
+ * | P1 --. P1 -> P2 : deny
+ * '------' \ P2 -> P1 : allow
+ * '
+ * P2
+ */
+FIXTURE_VARIANT_ADD(hierarchy, deny_with_parent_domain) {
+ .domain_both = false,
+ .domain_parent = true,
+ .domain_child = false,
+};
+
+/*
+ * Parent + child domain (siblings)
+ * .------.
+ * | P1 ---. P1 -> P2 : deny
+ * '------' \ P2 -> P1 : deny
+ * .---'--.
+ * | P2 |
+ * '------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, deny_with_sibling_domain) {
+ .domain_both = false,
+ .domain_parent = true,
+ .domain_child = true,
+};
+
+/*
+ * Same domain (inherited)
+ * .-------------.
+ * | P1----. | P1 -> P2 : allow
+ * | \ | P2 -> P1 : allow
+ * | ' |
+ * | P2 |
+ * '-------------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, allow_sibling_domain) {
+ .domain_both = true,
+ .domain_parent = false,
+ .domain_child = false,
+};
+
+/*
+ * Inherited + child domain
+ * .-----------------.
+ * | P1----. | P1 -> P2 : allow
+ * | \ | P2 -> P1 : deny
+ * | .-'----. |
+ * | | P2 | |
+ * | '------' |
+ * '-----------------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, allow_with_nested_domain) {
+ .domain_both = true,
+ .domain_parent = false,
+ .domain_child = true,
+};
+
+/*
+ * Inherited + parent domain
+ * .-----------------.
+ * |.------. | P1 -> P2 : deny
+ * || P1 ----. | P2 -> P1 : allow
+ * |'------' \ |
+ * | ' |
+ * | P2 |
+ * '-----------------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, deny_with_nested_and_parent_domain) {
+ .domain_both = true,
+ .domain_parent = true,
+ .domain_child = false,
+};
+
+/*
+ * Inherited + parent and child domain (siblings)
+ * .-----------------.
+ * | .------. | P1 -> P2 : deny
+ * | | P1 . | P2 -> P1 : deny
+ * | '------'\ |
+ * | \ |
+ * | .--'---. |
+ * | | P2 | |
+ * | '------' |
+ * '-----------------'
+ */
+FIXTURE_VARIANT_ADD(hierarchy, deny_with_forked_domain) {
+ .domain_both = true,
+ .domain_parent = true,
+ .domain_child = true,
+};
+
+FIXTURE_SETUP(hierarchy)
+{ }
+
+FIXTURE_TEARDOWN(hierarchy)
+{ }
+
+/* Test PTRACE_TRACEME and PTRACE_ATTACH for parent and child. */
+TEST_F(hierarchy, trace)
+{
+ pid_t child, parent;
+ int status, err_proc_read;
+ int pipe_child[2], pipe_parent[2];
+ char buf_parent;
+ long ret;
+
+ /*
+ * Removes all effective and permitted capabilities to not interfere
+ * with cap_ptrace_access_check() in case of PTRACE_MODE_FSCREDS.
+ */
+ drop_caps(_metadata);
+
+ parent = getpid();
+ ASSERT_EQ(0, pipe2(pipe_child, O_CLOEXEC));
+ ASSERT_EQ(0, pipe2(pipe_parent, O_CLOEXEC));
+ if (variant->domain_both) {
+ create_domain(_metadata);
+ if (!_metadata->passed)
+ /* Aborts before forking. */
+ return;
+ }
+
+ child = fork();
+ ASSERT_LE(0, child);
+ if (child == 0) {
+ char buf_child;
+
+ ASSERT_EQ(0, close(pipe_parent[1]));
+ ASSERT_EQ(0, close(pipe_child[0]));
+ if (variant->domain_child)
+ create_domain(_metadata);
+
+ /* Waits for the parent to be in a domain, if any. */
+ ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
+
+ /* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the parent. */
+ err_proc_read = test_ptrace_read(parent);
+ ret = ptrace(PTRACE_ATTACH, parent, NULL, 0);
+ if (variant->domain_child) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ EXPECT_EQ(EACCES, err_proc_read);
+ } else {
+ EXPECT_EQ(0, ret);
+ EXPECT_EQ(0, err_proc_read);
+ }
+ if (ret == 0) {
+ ASSERT_EQ(parent, waitpid(parent, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, parent, NULL, 0));
+ }
+
+ /* Tests child PTRACE_TRACEME. */
+ ret = ptrace(PTRACE_TRACEME);
+ if (variant->domain_parent) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ } else {
+ EXPECT_EQ(0, ret);
+ }
+
+ /*
+ * Signals that the PTRACE_ATTACH test is done and the
+ * PTRACE_TRACEME test is ongoing.
+ */
+ ASSERT_EQ(1, write(pipe_child[1], ".", 1));
+
+ if (!variant->domain_parent) {
+ ASSERT_EQ(0, raise(SIGSTOP));
+ }
+
+ /* Waits for the parent PTRACE_ATTACH test. */
+ ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
+ _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
+ return;
+ }
+
+ ASSERT_EQ(0, close(pipe_child[1]));
+ ASSERT_EQ(0, close(pipe_parent[0]));
+ if (variant->domain_parent)
+ create_domain(_metadata);
+
+ /* Signals that the parent is in a domain, if any. */
+ ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
+
+ /*
+ * Waits for the child to test PTRACE_ATTACH on the parent and start
+ * testing PTRACE_TRACEME.
+ */
+ ASSERT_EQ(1, read(pipe_child[0], &buf_parent, 1));
+
+ /* Tests child PTRACE_TRACEME. */
+ if (!variant->domain_parent) {
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
+ } else {
+ /* The child should not be traced by the parent. */
+ EXPECT_EQ(-1, ptrace(PTRACE_DETACH, child, NULL, 0));
+ EXPECT_EQ(ESRCH, errno);
+ }
+
+ /* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the child. */
+ err_proc_read = test_ptrace_read(child);
+ ret = ptrace(PTRACE_ATTACH, child, NULL, 0);
+ if (variant->domain_parent) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ EXPECT_EQ(EACCES, err_proc_read);
+ } else {
+ EXPECT_EQ(0, ret);
+ EXPECT_EQ(0, err_proc_read);
+ }
+ if (ret == 0) {
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
+ }
+
+ /* Signals that the parent PTRACE_ATTACH test is done. */
+ ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ if (WIFSIGNALED(status) || !WIFEXITED(status) ||
+ WEXITSTATUS(status) != EXIT_SUCCESS)
+ _metadata->passed = 0;
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/landlock/true.c b/tools/testing/selftests/landlock/true.c
new file mode 100644
index 000000000000..3f9ccbf52783
--- /dev/null
+++ b/tools/testing/selftests/landlock/true.c
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+int main(void)
+{
+ return 0;
+}
--
2.30.2
I've added this to my tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git landlock_lsm_v33
and merged that into the next-testing branch which is pulled into Linux
next.
--
James Morris
<[email protected]>
On 4/8/2021 6:48 PM, James Morris wrote:
> I've added this to my tree at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git landlock_lsm_v33
>
> and merged that into the next-testing branch which is pulled into Linux
> next.
Thank you.