Add three system calls for the Linux Security Module ABI.
lsm_get_self_attr() provides the security module specific attributes
that have previously been visible in the /proc/self/attr directory.
For each security module that uses the specified attribute on the
current process the system call will return an LSM identifier and
the value of the attribute. The LSM and attribute identifier values
are defined in include/uapi/linux/lsm.h
LSM identifiers are simple integers and reflect the order in which
the LSM was added to the mainline kernel. This is a convention, not
a promise of the API. LSM identifiers below the value of 100 are
reserved for unspecified future uses. That could include information
about the security infrastructure itself, or about how multiple LSMs
might interact with each other.
A new LSM hook security_getselfattr() is introduced to get the
required information from the security modules. This is similar
to the existing security_getprocattr() hook, but specifies the
format in which string data is returned and requires the module
to put the information into a userspace destination.
lsm_set_self_attr() changes the specified LSM attribute. Only one
attribute can be changed at a time, and then only if the specified
security module allows the change.
A new LSM hook security_setselfattr() is introduced to set the
required information in the security modules. This is similar
to the existing security_setprocattr() hook, but specifies the
format in which string data is presented and requires the module
to get the information from a userspace destination.
lsm_list_modules() provides the LSM identifiers, in order, of the
security modules that are active on the system. This has been
available in the securityfs file /sys/kernel/security/lsm.
Patch 0001 changes the LSM registration from passing the name
of the module to passing a lsm_id structure that contains the
name of the module, an LSM identifier number and an attribute
identifier.
Patch 0002 adds the registered lsm_ids to a table.
Patch 0003 changes security_[gs]etprocattr() to use LSM IDs instead
of LSM names.
Patch 0004 implements lsm_get_self_attr() and lsm_set_self_attr().
New LSM hooks security_getselfattr() and security_setselfattr() are
defined.
Patch 0005 implements lsm_list_modules().
Patch 0006 wires up the syscalls.
Patch 0007 implements helper functions to make it easier for
security modules to use lsm_ctx structures.
Patch 0008 provides the Smack implementation for [gs]etselfattr().
Patch 0009 provides the AppArmor implementation for [gs]etselfattr().
Patch 0010 provides the SELinux implementation for [gs]etselfattr().
Patch 0011 implements selftests for the three new syscalls.
https://github.com/cschaufler/lsm-stacking.git#lsm-syscalls-6.3-rc7-v10-e
v10: Correct use of __user.
Improve a few comments.
Revert unnecessary changes in module initialization.
v9: Support a flag LSM_FLAG_SINGLE in lsm_get_self_attr() that
instructs the call to provide only the attribute for the LSM
identified in the referenced lsm_ctx structure.
Fix a typing error.
Change some coding style.
v8: Allow an LSM to provide more than one instance of an attribute,
even though none of the existing modules do so.
Pad the data returned by lsm_get_self_attr() to the size of
the struct lsm_ctx.
Change some displeasing varilable names.
v7: Pass the attribute desired to lsm_[gs]et_self_attr in its own
parameter rather than encoding it in the flags.
Change the flags parameters to u32.
Don't shortcut out of calling LSM specific code in the
infrastructure, let the LSM report that doesn't support an
attribute instead. With that it is not necessary to maintain
a set of supported attributes in the lsm_id structure.
Fix a typing error.
v6: Switch from reusing security_[gs]procattr() to using new
security_[gs]selfattr() hooks. Use explicit sized data types
in the lsm_ctx structure.
v5: Correct syscall parameter data types.
v4: Restore "reserved" LSM ID values. Add explaination.
Squash patches that introduce fields in lsm_id.
Correct a wireup error.
v3: Add lsm_set_self_attr().
Rename lsm_self_attr() to lsm_get_self_attr().
Provide the values only for a specifed attribute in
lsm_get_self_attr().
Add selftests for the three new syscalls.
Correct some parameter checking.
v2: Use user-interface safe data types.
Remove "reserved" LSM ID values.
Improve kerneldoc comments
Include copyright dates
Use more descriptive name for LSM counter
Add documentation
Correct wireup errors
Casey Schaufler (11):
LSM: Identify modules by more than name
LSM: Maintain a table of LSM attribute data
proc: Use lsmids instead of lsm names for attrs
LSM: syscalls for current process attributes
LSM: Create lsm_list_modules system call
LSM: wireup Linux Security Module syscalls
LSM: Helpers for attribute names and filling lsm_ctx
Smack: implement setselfattr and getselfattr hooks
AppArmor: Add selfattr hooks
SELinux: Add selfattr hooks
LSM: selftests for Linux Security Module syscalls
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/lsm.rst | 73 +++++
MAINTAINERS | 1 +
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 +
fs/proc/base.c | 29 +-
fs/proc/internal.h | 2 +-
include/linux/lsm_hook_defs.h | 4 +
include/linux/lsm_hooks.h | 25 +-
include/linux/security.h | 45 ++-
include/linux/syscalls.h | 6 +
include/uapi/asm-generic/unistd.h | 11 +-
include/uapi/linux/lsm.h | 90 ++++++
kernel/sys_ni.c | 5 +
security/Makefile | 1 +
security/apparmor/include/procattr.h | 2 +-
security/apparmor/lsm.c | 110 ++++++-
security/apparmor/procattr.c | 10 +-
security/bpf/hooks.c | 9 +-
security/commoncap.c | 8 +-
security/landlock/cred.c | 2 +-
security/landlock/fs.c | 2 +-
security/landlock/ptrace.c | 2 +-
security/landlock/setup.c | 6 +
security/landlock/setup.h | 1 +
security/loadpin/loadpin.c | 9 +-
security/lockdown/lockdown.c | 8 +-
security/lsm_syscalls.c | 118 ++++++++
security/safesetid/lsm.c | 9 +-
security/security.c | 211 +++++++++++++-
security/selinux/hooks.c | 163 +++++++++--
security/smack/smack_lsm.c | 114 +++++++-
security/tomoyo/tomoyo.c | 9 +-
security/yama/yama_lsm.c | 8 +-
.../arch/mips/entry/syscalls/syscall_n64.tbl | 3 +
.../arch/powerpc/entry/syscalls/syscall.tbl | 3 +
.../perf/arch/s390/entry/syscalls/syscall.tbl | 3 +
.../arch/x86/entry/syscalls/syscall_64.tbl | 3 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/lsm/Makefile | 12 +
tools/testing/selftests/lsm/config | 2 +
.../selftests/lsm/lsm_get_self_attr_test.c | 270 ++++++++++++++++++
.../selftests/lsm/lsm_list_modules_test.c | 153 ++++++++++
.../selftests/lsm/lsm_set_self_attr_test.c | 70 +++++
60 files changed, 1576 insertions(+), 94 deletions(-)
create mode 100644 Documentation/userspace-api/lsm.rst
create mode 100644 include/uapi/linux/lsm.h
create mode 100644 security/lsm_syscalls.c
create mode 100644 tools/testing/selftests/lsm/Makefile
create mode 100644 tools/testing/selftests/lsm/config
create mode 100644 tools/testing/selftests/lsm/lsm_get_self_attr_test.c
create mode 100644 tools/testing/selftests/lsm/lsm_list_modules_test.c
create mode 100644 tools/testing/selftests/lsm/lsm_set_self_attr_test.c
--
2.39.2
Create a system call to report the list of Linux Security Modules
that are active on the system. The list is provided as an array
of LSM ID numbers.
The calling application can use this list determine what LSM
specific actions it might take. That might include choosing an
output format, determining required privilege or bypassing
security module specific behavior.
Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
---
Documentation/userspace-api/lsm.rst | 3 +++
include/linux/syscalls.h | 1 +
kernel/sys_ni.c | 1 +
security/lsm_syscalls.c | 39 +++++++++++++++++++++++++++++
4 files changed, 44 insertions(+)
diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst
index e6c3f262addc..9edae18a2688 100644
--- a/Documentation/userspace-api/lsm.rst
+++ b/Documentation/userspace-api/lsm.rst
@@ -63,6 +63,9 @@ Get the specified security attributes of the current process
.. kernel-doc:: security/lsm_syscalls.c
:identifiers: sys_lsm_get_self_attr
+.. kernel-doc:: security/lsm_syscalls.c
+ :identifiers: sys_lsm_list_modules
+
Additional documentation
========================
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 9a94c31bf6b6..ddbcc333f3c3 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1063,6 +1063,7 @@ asmlinkage long sys_lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx,
size_t *size, __u32 flags);
asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx,
size_t size, __u32 flags);
+asmlinkage long sys_lsm_list_modules(u64 *ids, size_t *size, u32 flags);
/*
* Architecture-specific system calls
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index d03c78ef1562..ceb3d21a62d0 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -265,6 +265,7 @@ COND_SYSCALL(mremap);
/* security/lsm_syscalls.c */
COND_SYSCALL(lsm_get_self_attr);
COND_SYSCALL(lsm_set_self_attr);
+COND_SYSCALL(lsm_list_modules);
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index ee3881159241..b89cccb2f123 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -53,3 +53,42 @@ SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
{
return security_getselfattr(attr, ctx, size, flags);
}
+
+/**
+ * sys_lsm_list_modules - Return a list of the active security modules
+ * @ids: the LSM module ids
+ * @size: size of @ids, updated on return
+ * @flags: reserved for future use, must be zero
+ *
+ * Returns a list of the active LSM ids. On success this function
+ * returns the number of @ids array elements. This value may be zero
+ * if there are no LSMs active. If @size is insufficient to contain
+ * the return data -E2BIG is returned and @size is set to the minimum
+ * required size. In all other cases a negative value indicating the
+ * error is returned.
+ */
+SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, size_t __user *, size,
+ u32, flags)
+{
+ size_t total_size = lsm_active_cnt * sizeof(*ids);
+ size_t usize;
+ int i;
+
+ if (flags)
+ return -EINVAL;
+
+ if (get_user(usize, size))
+ return -EFAULT;
+
+ if (put_user(total_size, size) != 0)
+ return -EFAULT;
+
+ if (usize < total_size)
+ return -E2BIG;
+
+ for (i = 0; i < lsm_active_cnt; i++)
+ if (put_user(lsm_idlist[i]->id, ids++))
+ return -EFAULT;
+
+ return lsm_active_cnt;
+}
--
2.39.2
Create a struct lsm_id to contain identifying information
about Linux Security Modules (LSMs). At inception this contains
the name of the module, an identifier associated with the security
module and an integer member "attrs" which identifies the API
related data associated with each security module. The initial set
of features maps to information that has traditionaly been available
in /proc/self/attr. They are documented in a new userspace-api file.
Change the security_add_hooks() interface to use this structure.
Change the individual modules to maintain their own struct lsm_id
and pass it to security_add_hooks().
The values are for LSM identifiers are defined in a new UAPI
header file linux/lsm.h. Each existing LSM has been updated to
include it's LSMID in the lsm_id.
The LSM ID values are sequential, with the oldest module
LSM_ID_CAPABILITY being the lowest value and the existing modules
numbered in the order they were included in the main line kernel.
This is an arbitrary convention for assigning the values, but
none better presents itself. The value 0 is defined as being invalid.
The values 1-99 are reserved for any special case uses which may
arise in the future. This may include attributes of the LSM
infrastructure itself, possibly related to namespacing or network
attribute management. A special range is identified for such attributes
to help reduce confusion for developers unfamiliar with LSMs.
LSM attribute values are defined for the attributes presented by
modules that are available today. As with the LSM IDs, The value 0
is defined as being invalid. The values 1-99 are reserved for any
special case uses which may arise in the future.
Signed-off-by: Casey Schaufler <[email protected]>
Cc: linux-security-module <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
---
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/lsm.rst | 55 +++++++++++++++++++++++++++
MAINTAINERS | 1 +
include/linux/lsm_hooks.h | 16 +++++++-
include/uapi/linux/lsm.h | 54 ++++++++++++++++++++++++++
security/apparmor/lsm.c | 8 +++-
security/bpf/hooks.c | 9 ++++-
security/commoncap.c | 8 +++-
security/landlock/cred.c | 2 +-
security/landlock/fs.c | 2 +-
security/landlock/ptrace.c | 2 +-
security/landlock/setup.c | 6 +++
security/landlock/setup.h | 1 +
security/loadpin/loadpin.c | 9 ++++-
security/lockdown/lockdown.c | 8 +++-
security/safesetid/lsm.c | 9 ++++-
security/security.c | 12 +++---
security/selinux/hooks.c | 9 ++++-
security/smack/smack_lsm.c | 8 +++-
security/tomoyo/tomoyo.c | 9 ++++-
security/yama/yama_lsm.c | 8 +++-
21 files changed, 216 insertions(+), 21 deletions(-)
create mode 100644 Documentation/userspace-api/lsm.rst
create mode 100644 include/uapi/linux/lsm.h
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index f16337bdb852..54c0f54cde89 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -31,6 +31,7 @@ place where this information is gathered.
sysfs-platform_profile
vduse
futex2
+ lsm
.. only:: subproject and html
diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst
new file mode 100644
index 000000000000..6ddf5506110b
--- /dev/null
+++ b/Documentation/userspace-api/lsm.rst
@@ -0,0 +1,55 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. Copyright (C) 2022 Casey Schaufler <[email protected]>
+.. Copyright (C) 2022 Intel Corporation
+
+=====================================
+Linux Security Modules
+=====================================
+
+:Author: Casey Schaufler
+:Date: November 2022
+
+Linux security modules (LSM) provide a mechanism to implement
+additional access controls to the Linux security policies.
+
+The various security modules may support any of these attributes:
+
+``LSM_ATTR_CURRENT`` is the current, active security context of the
+process.
+The proc filesystem provides this value in ``/proc/self/attr/current``.
+This is supported by the SELinux, Smack and AppArmor security modules.
+Smack also provides this value in ``/proc/self/attr/smack/current``.
+AppArmor also provides this value in ``/proc/self/attr/apparmor/current``.
+
+``LSM_ATTR_EXEC`` is the security context of the process at the time the
+current image was executed.
+The proc filesystem provides this value in ``/proc/self/attr/exec``.
+This is supported by the SELinux and AppArmor security modules.
+AppArmor also provides this value in ``/proc/self/attr/apparmor/exec``.
+
+``LSM_ATTR_FSCREATE`` is the security context of the process used when
+creating file system objects.
+The proc filesystem provides this value in ``/proc/self/attr/fscreate``.
+This is supported by the SELinux security module.
+
+``LSM_ATTR_KEYCREATE`` is the security context of the process used when
+creating key objects.
+The proc filesystem provides this value in ``/proc/self/attr/keycreate``.
+This is supported by the SELinux security module.
+
+``LSM_ATTR_PREV`` is the security context of the process at the time the
+current security context was set.
+The proc filesystem provides this value in ``/proc/self/attr/prev``.
+This is supported by the SELinux and AppArmor security modules.
+AppArmor also provides this value in ``/proc/self/attr/apparmor/prev``.
+
+``LSM_ATTR_SOCKCREATE`` is the security context of the process used when
+creating socket objects.
+The proc filesystem provides this value in ``/proc/self/attr/sockcreate``.
+This is supported by the SELinux security module.
+
+Additional documentation
+========================
+
+* Documentation/security/lsm.rst
+* Documentation/security/lsm-development.rst
diff --git a/MAINTAINERS b/MAINTAINERS
index 0e64787aace8..25d09f6eb3ef 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18810,6 +18810,7 @@ S: Supported
W: http://kernsec.org/
T: git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git
F: security/
+F: include/uapi/linux/lsm.h
X: security/selinux/
SELINUX SECURITY MODULE
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 6e156d2acffc..c1f00d09033e 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1665,6 +1665,18 @@ struct security_hook_heads {
#undef LSM_HOOK
} __randomize_layout;
+/**
+ * struct lsm_id - Identify a Linux Security Module.
+ * @lsm: name of the LSM, must be approved by the LSM maintainers
+ * @id: LSM ID number from uapi/linux/lsm.h
+ *
+ * Contains the information that identifies the LSM.
+ */
+struct lsm_id {
+ const char *name;
+ u64 id;
+};
+
/*
* Security module hook list structure.
* For use with generic list macros for common operations.
@@ -1673,7 +1685,7 @@ struct security_hook_list {
struct hlist_node list;
struct hlist_head *head;
union security_list_options hook;
- const char *lsm;
+ struct lsm_id *lsmid;
} __randomize_layout;
/*
@@ -1708,7 +1720,7 @@ extern struct security_hook_heads security_hook_heads;
extern char *lsm_names;
extern void security_add_hooks(struct security_hook_list *hooks, int count,
- const char *lsm);
+ struct lsm_id *lsmid);
#define LSM_FLAG_LEGACY_MAJOR BIT(0)
#define LSM_FLAG_EXCLUSIVE BIT(1)
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
new file mode 100644
index 000000000000..f27c9a9cc376
--- /dev/null
+++ b/include/uapi/linux/lsm.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Linux Security Modules (LSM) - User space API
+ *
+ * Copyright (C) 2022 Casey Schaufler <[email protected]>
+ * Copyright (C) 2022 Intel Corporation
+ */
+
+#ifndef _UAPI_LINUX_LSM_H
+#define _UAPI_LINUX_LSM_H
+
+/*
+ * ID tokens to identify Linux Security Modules (LSMs)
+ *
+ * These token values are used to uniquely identify specific LSMs
+ * in the kernel as well as in the kernel's LSM userspace API.
+ *
+ * A value of zero/0 is considered undefined and should not be used
+ * outside the kernel. Values 1-99 are reserved for potential
+ * future use.
+ */
+#define LSM_ID_UNDEF 0
+#define LSM_ID_CAPABILITY 100
+#define LSM_ID_SELINUX 101
+#define LSM_ID_SMACK 102
+#define LSM_ID_TOMOYO 103
+#define LSM_ID_IMA 104
+#define LSM_ID_APPARMOR 105
+#define LSM_ID_YAMA 106
+#define LSM_ID_LOADPIN 107
+#define LSM_ID_SAFESETID 108
+#define LSM_ID_LOCKDOWN 109
+#define LSM_ID_BPF 110
+#define LSM_ID_LANDLOCK 111
+
+/*
+ * LSM_ATTR_XXX definitions identify different LSM attributes
+ * which are used in the kernel's LSM userspace API. Support
+ * for these attributes vary across the different LSMs. None
+ * are required.
+ *
+ * A value of zero/0 is considered undefined and should not be used
+ * outside the kernel. Values 1-99 are reserved for potential
+ * future use.
+ */
+#define LSM_ATTR_UNDEF 0
+#define LSM_ATTR_CURRENT 100
+#define LSM_ATTR_EXEC 101
+#define LSM_ATTR_FSCREATE 102
+#define LSM_ATTR_KEYCREATE 103
+#define LSM_ATTR_PREV 104
+#define LSM_ATTR_SOCKCREATE 105
+
+#endif /* _UAPI_LINUX_LSM_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index d6cc4812ca53..d7f22b0cf03f 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -24,6 +24,7 @@
#include <linux/zstd.h>
#include <net/sock.h>
#include <uapi/linux/mount.h>
+#include <uapi/linux/lsm.h>
#include "include/apparmor.h"
#include "include/apparmorfs.h"
@@ -1215,6 +1216,11 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
.lbs_task = sizeof(struct aa_task_ctx),
};
+static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
+ .name = "apparmor",
+ .id = LSM_ID_APPARMOR,
+};
+
static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -1910,7 +1916,7 @@ static int __init apparmor_init(void)
goto buffers_out;
}
security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
- "apparmor");
+ &apparmor_lsmid);
/* Report that AppArmor successfully initialized */
apparmor_initialized = 1;
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index e5971fa74fd7..b6e71c5a401d 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -5,6 +5,7 @@
*/
#include <linux/lsm_hooks.h>
#include <linux/bpf_lsm.h>
+#include <uapi/linux/lsm.h>
static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
@@ -15,9 +16,15 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(task_free, bpf_task_storage_free),
};
+static struct lsm_id bpf_lsmid __lsm_ro_after_init = {
+ .name = "bpf",
+ .id = LSM_ID_BPF,
+};
+
static int __init bpf_lsm_init(void)
{
- security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf");
+ security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks),
+ &bpf_lsmid);
pr_info("LSM support for eBPF active\n");
return 0;
}
diff --git a/security/commoncap.c b/security/commoncap.c
index 5bb7d1e96277..69958af95163 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -25,6 +25,7 @@
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/mnt_idmapping.h>
+#include <uapi/linux/lsm.h>
/*
* If a non-root user executes a setuid-root binary in
@@ -1440,6 +1441,11 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
#ifdef CONFIG_SECURITY
+static struct lsm_id capability_lsmid __lsm_ro_after_init = {
+ .name = "capability",
+ .id = LSM_ID_CAPABILITY,
+};
+
static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(capable, cap_capable),
LSM_HOOK_INIT(settime, cap_settime),
@@ -1464,7 +1470,7 @@ static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
static int __init capability_init(void)
{
security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
- "capability");
+ &capability_lsmid);
return 0;
}
diff --git a/security/landlock/cred.c b/security/landlock/cred.c
index ec6c37f04a19..2eb1d65f10d6 100644
--- a/security/landlock/cred.c
+++ b/security/landlock/cred.c
@@ -42,5 +42,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
__init void landlock_add_cred_hooks(void)
{
security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
- LANDLOCK_NAME);
+ &landlock_lsmid);
}
diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index adcea0fe7e68..fa0e6e76991c 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -1307,5 +1307,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
__init void landlock_add_fs_hooks(void)
{
security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
- LANDLOCK_NAME);
+ &landlock_lsmid);
}
diff --git a/security/landlock/ptrace.c b/security/landlock/ptrace.c
index 4c5b9cd71286..eab35808f395 100644
--- a/security/landlock/ptrace.c
+++ b/security/landlock/ptrace.c
@@ -116,5 +116,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
__init void landlock_add_ptrace_hooks(void)
{
security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
- LANDLOCK_NAME);
+ &landlock_lsmid);
}
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
index 3f196d2ce4f9..17116c87f268 100644
--- a/security/landlock/setup.c
+++ b/security/landlock/setup.c
@@ -8,6 +8,7 @@
#include <linux/init.h>
#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
#include "common.h"
#include "cred.h"
@@ -24,6 +25,11 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
.lbs_superblock = sizeof(struct landlock_superblock_security),
};
+struct lsm_id landlock_lsmid __lsm_ro_after_init = {
+ .name = LANDLOCK_NAME,
+ .id = LSM_ID_LANDLOCK,
+};
+
static int __init landlock_init(void)
{
landlock_add_cred_hooks();
diff --git a/security/landlock/setup.h b/security/landlock/setup.h
index 1daffab1ab4b..38bce5b172dc 100644
--- a/security/landlock/setup.h
+++ b/security/landlock/setup.h
@@ -14,5 +14,6 @@
extern bool landlock_initialized;
extern struct lsm_blob_sizes landlock_blob_sizes;
+extern struct lsm_id landlock_lsmid;
#endif /* _SECURITY_LANDLOCK_SETUP_H */
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index d73a281adf86..d359f2ea1a0a 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -20,6 +20,7 @@
#include <linux/string_helpers.h>
#include <linux/dm-verity-loadpin.h>
#include <uapi/linux/loadpin.h>
+#include <uapi/linux/lsm.h>
#define VERITY_DIGEST_FILE_HEADER "# LOADPIN_TRUSTED_VERITY_ROOT_DIGESTS"
@@ -214,6 +215,11 @@ static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
return loadpin_check(NULL, (enum kernel_read_file_id) id);
}
+static struct lsm_id loadpin_lsmid __lsm_ro_after_init = {
+ .name = "loadpin",
+ .id = LSM_ID_LOADPIN,
+};
+
static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
@@ -265,7 +271,8 @@ static int __init loadpin_init(void)
if (!register_sysctl_paths(loadpin_sysctl_path, loadpin_sysctl_table))
pr_notice("sysctl registration failed!\n");
#endif
- security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), "loadpin");
+ security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks),
+ &loadpin_lsmid);
return 0;
}
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index a79b985e917e..141a0b94098e 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -13,6 +13,7 @@
#include <linux/security.h>
#include <linux/export.h>
#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
static enum lockdown_reason kernel_locked_down;
@@ -75,6 +76,11 @@ static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),
};
+static struct lsm_id lockdown_lsmid __lsm_ro_after_init = {
+ .name = "lockdown",
+ .id = LSM_ID_LOCKDOWN,
+};
+
static int __init lockdown_lsm_init(void)
{
#if defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY)
@@ -83,7 +89,7 @@ static int __init lockdown_lsm_init(void)
lock_kernel_down("Kernel configuration", LOCKDOWN_CONFIDENTIALITY_MAX);
#endif
security_add_hooks(lockdown_hooks, ARRAY_SIZE(lockdown_hooks),
- "lockdown");
+ &lockdown_lsmid);
return 0;
}
diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
index e806739f7868..86b57785f86e 100644
--- a/security/safesetid/lsm.c
+++ b/security/safesetid/lsm.c
@@ -19,6 +19,7 @@
#include <linux/ptrace.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
+#include <uapi/linux/lsm.h>
#include "lsm.h"
/* Flag indicating whether initialization completed */
@@ -261,6 +262,11 @@ static int safesetid_task_fix_setgroups(struct cred *new, const struct cred *old
return 0;
}
+static struct lsm_id safesetid_lsmid __lsm_ro_after_init = {
+ .name = "safesetid",
+ .id = LSM_ID_SAFESETID,
+};
+
static struct security_hook_list safesetid_security_hooks[] = {
LSM_HOOK_INIT(task_fix_setuid, safesetid_task_fix_setuid),
LSM_HOOK_INIT(task_fix_setgid, safesetid_task_fix_setgid),
@@ -271,7 +277,8 @@ static struct security_hook_list safesetid_security_hooks[] = {
static int __init safesetid_security_init(void)
{
security_add_hooks(safesetid_security_hooks,
- ARRAY_SIZE(safesetid_security_hooks), "safesetid");
+ ARRAY_SIZE(safesetid_security_hooks),
+ &safesetid_lsmid);
/* Report that SafeSetID successfully initialized */
safesetid_initialized = 1;
diff --git a/security/security.c b/security/security.c
index cf6cc576736f..a482c6048df9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -504,17 +504,17 @@ static int lsm_append(const char *new, char **result)
* security_add_hooks - Add a modules hooks to the hook lists.
* @hooks: the hooks to add
* @count: the number of hooks to add
- * @lsm: the name of the security module
+ * @lsmid: the identification information for the security module
*
* Each LSM has to register its hooks with the infrastructure.
*/
void __init security_add_hooks(struct security_hook_list *hooks, int count,
- const char *lsm)
+ struct lsm_id *lsmid)
{
int i;
for (i = 0; i < count; i++) {
- hooks[i].lsm = lsm;
+ hooks[i].lsmid = lsmid;
hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
}
@@ -523,7 +523,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
* and fix this up afterwards.
*/
if (slab_is_available()) {
- if (lsm_append(lsm, &lsm_names) < 0)
+ if (lsm_append(lsmid->name, &lsm_names) < 0)
panic("%s - Cannot get early memory.\n", __func__);
}
}
@@ -2146,7 +2146,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm,
struct security_hook_list *hp;
hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
- if (lsm != NULL && strcmp(lsm, hp->lsm))
+ if (lsm != NULL && strcmp(lsm, hp->lsmid->name))
continue;
return hp->hook.getprocattr(p, name, value);
}
@@ -2159,7 +2159,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
struct security_hook_list *hp;
hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
- if (lsm != NULL && strcmp(lsm, hp->lsm))
+ if (lsm != NULL && strcmp(lsm, hp->lsmid->name))
continue;
return hp->hook.setprocattr(name, value, size);
}
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9a5bdfc21314..2ee92d3fb79d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -92,6 +92,7 @@
#include <linux/fsnotify.h>
#include <linux/fanotify.h>
#include <linux/io_uring.h>
+#include <uapi/linux/lsm.h>
#include "avc.h"
#include "objsec.h"
@@ -7032,6 +7033,11 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd)
}
#endif /* CONFIG_IO_URING */
+static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
+ .name = "selinux",
+ .id = LSM_ID_SELINUX,
+};
+
/*
* IMPORTANT NOTE: When adding new hooks, please be careful to keep this order:
* 1. any hooks that don't belong to (2.) or (3.) below,
@@ -7355,7 +7361,8 @@ static __init int selinux_init(void)
hashtab_cache_init();
- security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux");
+ security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks),
+ &selinux_lsmid);
if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
panic("SELinux: Unable to register AVC netcache callback\n");
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index cfcbb748da25..0b466d3b31b7 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -43,6 +43,7 @@
#include <linux/fs_parser.h>
#include <linux/watch_queue.h>
#include <linux/io_uring.h>
+#include <uapi/linux/lsm.h>
#include "smack.h"
#define TRANS_TRUE "TRUE"
@@ -4856,6 +4857,11 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
.lbs_superblock = sizeof(struct superblock_smack),
};
+static struct lsm_id smack_lsmid __lsm_ro_after_init = {
+ .name = "smack",
+ .id = LSM_ID_SMACK,
+};
+
static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
@@ -5062,7 +5068,7 @@ static __init int smack_init(void)
/*
* Register with LSM
*/
- security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
+ security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), &smack_lsmid);
smack_enabled = 1;
pr_info("Smack: Initializing.\n");
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index af04a7b7eb28..7de4fcdcbf90 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -6,6 +6,7 @@
*/
#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
#include "common.h"
/**
@@ -542,6 +543,11 @@ static void tomoyo_task_free(struct task_struct *task)
}
}
+static struct lsm_id tomoyo_lsmid __lsm_ro_after_init = {
+ .name = "tomoyo",
+ .id = LSM_ID_TOMOYO,
+};
+
/*
* tomoyo_security_ops is a "struct security_operations" which is used for
* registering TOMOYO.
@@ -595,7 +601,8 @@ static int __init tomoyo_init(void)
struct tomoyo_task *s = tomoyo_task(current);
/* register ourselves with the security framework */
- security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo");
+ security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks),
+ &tomoyo_lsmid);
pr_info("TOMOYO Linux initialized\n");
s->domain_info = &tomoyo_kernel_domain;
atomic_inc(&tomoyo_kernel_domain.users);
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 06e226166aab..c56572ec9d50 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -18,6 +18,7 @@
#include <linux/task_work.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
+#include <uapi/linux/lsm.h>
#define YAMA_SCOPE_DISABLED 0
#define YAMA_SCOPE_RELATIONAL 1
@@ -421,6 +422,11 @@ static int yama_ptrace_traceme(struct task_struct *parent)
return rc;
}
+static struct lsm_id yama_lsmid __lsm_ro_after_init = {
+ .name = "yama",
+ .id = LSM_ID_YAMA,
+};
+
static struct security_hook_list yama_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, yama_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, yama_ptrace_traceme),
@@ -477,7 +483,7 @@ static inline void yama_init_sysctl(void) { }
static int __init yama_init(void)
{
pr_info("Yama: becoming mindful.\n");
- security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), "yama");
+ security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), &yama_lsmid);
yama_init_sysctl();
return 0;
}
--
2.39.2
Create a system call lsm_get_self_attr() to provide the security
module maintained attributes of the current process.
Create a system call lsm_set_self_attr() to set a security
module maintained attribute of the current process.
Historically these attributes have been exposed to user space via
entries in procfs under /proc/self/attr.
The attribute value is provided in a lsm_ctx structure. The structure
identifies the size of the attribute, and the attribute value. The format
of the attribute value is defined by the security module. A flags field
is included for LSM specific information. It is currently unused and must
be 0. The total size of the data, including the lsm_ctx structure and any
padding, is maintained as well.
struct lsm_ctx {
__u64 id;
__u64 flags;
__u64 len;
__u64 ctx_len;
__u8 ctx[];
};
Two new LSM hooks are used to interface with the LSMs.
security_getselfattr() collects the lsm_ctx values from the
LSMs that support the hook, accounting for space requirements.
security_setselfattr() identifies which LSM the attribute is
intended for and passes it along.
Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
---
Documentation/userspace-api/lsm.rst | 15 ++++
include/linux/lsm_hook_defs.h | 4 +
include/linux/lsm_hooks.h | 9 +++
include/linux/security.h | 19 +++++
include/linux/syscalls.h | 5 ++
include/uapi/linux/lsm.h | 36 +++++++++
kernel/sys_ni.c | 4 +
security/Makefile | 1 +
security/lsm_syscalls.c | 55 ++++++++++++++
security/security.c | 112 ++++++++++++++++++++++++++++
10 files changed, 260 insertions(+)
create mode 100644 security/lsm_syscalls.c
diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst
index 6ddf5506110b..e6c3f262addc 100644
--- a/Documentation/userspace-api/lsm.rst
+++ b/Documentation/userspace-api/lsm.rst
@@ -48,6 +48,21 @@ creating socket objects.
The proc filesystem provides this value in ``/proc/self/attr/sockcreate``.
This is supported by the SELinux security module.
+Kernel interface
+================
+
+Set a security attribute of the current process
+-----------------------------------------------
+
+.. kernel-doc:: security/lsm_syscalls.c
+ :identifiers: sys_lsm_set_self_attr
+
+Get the specified security attributes of the current process
+------------------------------------------------------------
+
+.. kernel-doc:: security/lsm_syscalls.c
+ :identifiers: sys_lsm_get_self_attr
+
Additional documentation
========================
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 094b76dc7164..32104ff61999 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -261,6 +261,10 @@ LSM_HOOK(int, 0, sem_semop, struct kern_ipc_perm *perm, struct sembuf *sops,
LSM_HOOK(int, 0, netlink_send, struct sock *sk, struct sk_buff *skb)
LSM_HOOK(void, LSM_RET_VOID, d_instantiate, struct dentry *dentry,
struct inode *inode)
+LSM_HOOK(int, -EOPNOTSUPP, getselfattr, unsigned int attr,
+ struct lsm_ctx __user *ctx, size_t *size, u32 flags)
+LSM_HOOK(int, -EOPNOTSUPP, setselfattr, unsigned int attr,
+ struct lsm_ctx __user *ctx, size_t size, u32 flags)
LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name,
char **value)
LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index c1f00d09033e..457ff953e331 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -25,6 +25,7 @@
#ifndef __LINUX_LSM_HOOKS_H
#define __LINUX_LSM_HOOKS_H
+#include <uapi/linux/lsm.h>
#include <linux/security.h>
#include <linux/init.h>
#include <linux/rculist.h>
@@ -503,6 +504,14 @@
* and writing the xattrs as this hook is merely a filter.
* @d_instantiate:
* Fill in @inode security information for a @dentry if allowed.
+ * @getselfattr:
+ * Read attribute @attr for the current process and store it into @ctx.
+ * Return 0 on success, -EOPNOTSUPP if the attribute is not supported,
+ * or another negative value otherwise.
+ * @setselfattr:
+ * Set attribute @attr for the current process.
+ * Return 0 on success, -EOPNOTSUPP if the attribute is not supported,
+ * or another negative value otherwise.
* @getprocattr:
* Read attribute @name for process @p and store it into @value if allowed.
* Return the length of @value on success, a negative value otherwise.
diff --git a/include/linux/security.h b/include/linux/security.h
index 8faed81fc3b4..806bff425af9 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -60,6 +60,7 @@ struct fs_parameter;
enum fs_value_type;
struct watch;
struct watch_notification;
+struct lsm_ctx;
/* Default (no) options for the capable function */
#define CAP_OPT_NONE 0x0
@@ -473,6 +474,10 @@ int security_sem_semctl(struct kern_ipc_perm *sma, int cmd);
int security_sem_semop(struct kern_ipc_perm *sma, struct sembuf *sops,
unsigned nsops, int alter);
void security_d_instantiate(struct dentry *dentry, struct inode *inode);
+int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t __user *size, u32 flags);
+int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t size, u32 flags);
int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
char **value);
int security_setprocattr(int lsmid, const char *name, void *value, size_t size);
@@ -1343,6 +1348,20 @@ static inline void security_d_instantiate(struct dentry *dentry,
struct inode *inode)
{ }
+static inline int security_getselfattr(unsigned int attr,
+ struct lsm_ctx __user *ctx,
+ size_t __user *size, u32 flags)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int security_setselfattr(unsigned int attr,
+ struct lsm_ctx __user *ctx,
+ size_t size, u32 flags)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int security_getprocattr(struct task_struct *p, int lsmid,
const char *name, char **value)
{
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 33a0ee3bcb2e..9a94c31bf6b6 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -71,6 +71,7 @@ struct clone_args;
struct open_how;
struct mount_attr;
struct landlock_ruleset_attr;
+struct lsm_ctx;
enum landlock_rule_type;
#include <linux/types.h>
@@ -1058,6 +1059,10 @@ asmlinkage long sys_memfd_secret(unsigned int flags);
asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long len,
unsigned long home_node,
unsigned long flags);
+asmlinkage long sys_lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx,
+ size_t *size, __u32 flags);
+asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx,
+ size_t size, __u32 flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
index f27c9a9cc376..eeda59a77c02 100644
--- a/include/uapi/linux/lsm.h
+++ b/include/uapi/linux/lsm.h
@@ -9,6 +9,36 @@
#ifndef _UAPI_LINUX_LSM_H
#define _UAPI_LINUX_LSM_H
+#include <linux/types.h>
+#include <linux/unistd.h>
+
+/**
+ * struct lsm_ctx - LSM context information
+ * @id: the LSM id number, see LSM_ID_XXX
+ * @flags: LSM specific flags
+ * @len: length of the lsm_ctx struct, @ctx and any other data or padding
+ * @ctx_len: the size of @ctx
+ * @ctx: the LSM context value
+ *
+ * The @len field MUST be equal to the size of the lsm_ctx struct
+ * plus any additional padding and/or data placed after @ctx.
+ *
+ * In all cases @ctx_len MUST be equal to the length of @ctx.
+ * If @ctx is a string value it should be nul terminated with
+ * @ctx_len equal to `strlen(@ctx) + 1`. Binary values are
+ * supported.
+ *
+ * The @flags and @ctx fields SHOULD only be interpreted by the
+ * LSM specified by @id; they MUST be set to zero/0 when not used.
+ */
+struct lsm_ctx {
+ __u64 id;
+ __u64 flags;
+ __u64 len;
+ __u64 ctx_len;
+ __u8 ctx[];
+};
+
/*
* ID tokens to identify Linux Security Modules (LSMs)
*
@@ -51,4 +81,10 @@
#define LSM_ATTR_PREV 104
#define LSM_ATTR_SOCKCREATE 105
+/*
+ * LSM_FLAG_XXX definitions identify special handling instructions
+ * for the API.
+ */
+#define LSM_FLAG_SINGLE 0x0001
+
#endif /* _UAPI_LINUX_LSM_H */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 860b2dcf3ac4..d03c78ef1562 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -262,6 +262,10 @@ COND_SYSCALL_COMPAT(recvmsg);
/* mm/nommu.c, also with MMU */
COND_SYSCALL(mremap);
+/* security/lsm_syscalls.c */
+COND_SYSCALL(lsm_get_self_attr);
+COND_SYSCALL(lsm_set_self_attr);
+
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
COND_SYSCALL(request_key);
diff --git a/security/Makefile b/security/Makefile
index 18121f8f85cd..59f238490665 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_KEYS) += keys/
# always enable default capabilities
obj-y += commoncap.o
+obj-$(CONFIG_SECURITY) += lsm_syscalls.o
obj-$(CONFIG_MMU) += min_addr.o
# Object file lists
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
new file mode 100644
index 000000000000..ee3881159241
--- /dev/null
+++ b/security/lsm_syscalls.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * System calls implementing the Linux Security Module API.
+ *
+ * Copyright (C) 2022 Casey Schaufler <[email protected]>
+ * Copyright (C) 2022 Intel Corporation
+ */
+
+#include <asm/current.h>
+#include <linux/compiler_types.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/security.h>
+#include <linux/stddef.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
+
+/**
+ * sys_lsm_set_self_attr - Set current task's security module attribute
+ * @attr: which attribute to set
+ * @ctx: the LSM contexts
+ * @size: size of @ctx
+ * @flags: reserved for future use
+ *
+ * Sets the calling task's LSM context. On success this function
+ * returns 0. If the attribute specified cannot be set a negative
+ * value indicating the reason for the error is returned.
+ */
+SYSCALL_DEFINE4(lsm_set_self_attr, unsigned int, attr, struct lsm_ctx __user *,
+ ctx, size_t, size, u32, flags)
+{
+ return security_setselfattr(attr, ctx, size, flags);
+}
+
+/**
+ * sys_lsm_get_self_attr - Return current task's security module attributes
+ * @attr: which attribute to set
+ * @ctx: the LSM contexts
+ * @size: size of @ctx, updated on return
+ * @flags: reserved for future use
+ *
+ * Returns the calling task's LSM contexts. On success this
+ * function returns the number of @ctx array elements. This value
+ * may be zero if there are no LSM contexts assigned. If @size is
+ * insufficient to contain the return data -E2BIG is returned and
+ * @size is set to the minimum required size. In all other cases
+ * a negative value indicating the error is returned.
+ */
+SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
+ ctx, size_t __user *, size, u32, flags)
+{
+ return security_getselfattr(attr, ctx, size, flags);
+}
diff --git a/security/security.c b/security/security.c
index 5a48b1b539e5..94b78bfd06b9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2176,6 +2176,118 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
}
EXPORT_SYMBOL(security_d_instantiate);
+/**
+ * security_getselfattr - Read an LSM attribute of the current process.
+ * @attr: which attribute to return
+ * @ctx: the user-space destination for the information, or NULL
+ * @size: the size of space available to receive the data
+ * @flags: special handling options. LSM_FLAG_SINGLE indicates that only
+ * attributes associated with the LSM identified in the passed @ctx be
+ * reported
+ *
+ * Returns the number of attributes found on success, negative value
+ * on error. @size is reset to the total size of the data.
+ * If @size is insufficient to contain the data -E2BIG is returned.
+ */
+int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t __user *size, u32 flags)
+{
+ struct security_hook_list *hp;
+ struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, };
+ u8 __user *base = (u8 __user *)ctx;
+ size_t total = 0;
+ size_t entrysize;
+ size_t left;
+ bool toobig = false;
+ int count = 0;
+ int rc;
+
+ if (attr == 0)
+ return -EINVAL;
+ if (size == NULL)
+ return -EINVAL;
+ if (get_user(left, size))
+ return -EFAULT;
+
+ if ((flags & LSM_FLAG_SINGLE) == LSM_FLAG_SINGLE) {
+ if (!ctx)
+ return -EINVAL;
+ if (copy_struct_from_user(&lctx, sizeof(lctx), ctx, left))
+ return -EFAULT;
+ if (lctx.id == LSM_ID_UNDEF)
+ return -EINVAL;
+ } else if (flags) {
+ return -EINVAL;
+ }
+
+ hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) {
+ if (lctx.id != LSM_ID_UNDEF && lctx.id != hp->lsmid->id)
+ continue;
+ entrysize = left;
+ if (base)
+ ctx = (struct lsm_ctx __user *)(base + total);
+ rc = hp->hook.getselfattr(attr, ctx, &entrysize, flags);
+ if (rc == -EOPNOTSUPP) {
+ rc = 0;
+ continue;
+ }
+ if (rc == -E2BIG) {
+ toobig = true;
+ left = 0;
+ continue;
+ }
+ if (rc < 0)
+ return rc;
+
+ left -= entrysize;
+ total += entrysize;
+ count += rc;
+ }
+ if (put_user(total, size))
+ return -EFAULT;
+ if (toobig)
+ return -E2BIG;
+ if (count == 0)
+ return LSM_RET_DEFAULT(getselfattr);
+ return count;
+}
+
+/**
+ * security_setselfattr - Set an LSM attribute on the current process.
+ * @attr: which attribute to set
+ * @ctx: the user-space source for the information
+ * @size: the size of the data
+ * @flags: reserved for future use, must be 0
+ *
+ * Set an LSM attribute for the current process. The LSM, attribute
+ * and new value are included in @ctx.
+ *
+ * Returns 0 on success, -EINVAL if the input is inconsistent, -EFAULT
+ * if the user buffer is inaccessible or an LSM specific failure.
+ */
+int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t size, u32 flags)
+{
+ struct security_hook_list *hp;
+ struct lsm_ctx lctx;
+
+ if (flags)
+ return -EINVAL;
+ if (size < sizeof(*ctx))
+ return -EINVAL;
+ if (copy_from_user(&lctx, ctx, sizeof(*ctx)))
+ return -EFAULT;
+ if (size < lctx.len || size < lctx.ctx_len + sizeof(ctx) ||
+ lctx.len < lctx.ctx_len + sizeof(ctx))
+ return -EINVAL;
+
+ hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list)
+ if ((hp->lsmid->id) == lctx.id)
+ return hp->hook.setselfattr(attr, ctx, size, flags);
+
+ return LSM_RET_DEFAULT(setselfattr);
+}
+
int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
char **value)
{
--
2.39.2
Wireup lsm_get_self_attr, lsm_set_self_attr and lsm_list_modules
system calls.
Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Cc: [email protected]
---
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 | 11 ++++++++++-
tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl | 3 +++
tools/perf/arch/powerpc/entry/syscalls/syscall.tbl | 3 +++
tools/perf/arch/s390/entry/syscalls/syscall.tbl | 3 +++
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl | 3 +++
23 files changed, 77 insertions(+), 2 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 8ebacf37a8cf..178e2792c251 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -490,3 +490,6 @@
558 common process_mrelease sys_process_mrelease
559 common futex_waitv sys_futex_waitv
560 common set_mempolicy_home_node sys_ni_syscall
+561 common lsm_get_self_attr sys_lsm_get_self_attr
+562 common lsm_list_modules sys_lsm_list_modules
+563 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index ac964612d8b0..9cda144f9631 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -464,3 +464,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 037feba03a51..6a28fb91b85d 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -39,7 +39,7 @@
#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 451
+#define __NR_compat_syscalls 454
#endif
#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 604a2053d006..72022ffd5faa 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -907,6 +907,12 @@ __SYSCALL(__NR_process_mrelease, sys_process_mrelease)
__SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
+#define __NR_lsm_get_self_attr 451
+__SYSCALL(__NR_lsm_get_self_attr, sys_lsm_get_self_attr)
+#define __NR_lsm_list_modules 452
+__SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
+#define __NR_lsm_set_self_attr 453
+__SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr)
/*
* 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 72c929d9902b..c52e9d87f47d 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -371,3 +371,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index b1f3940bc298..31eac3c99d84 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -450,3 +450,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 820145e47350..5037fa1f74b8 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -456,3 +456,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 253ff994ed2e..29545b3ec587 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -389,3 +389,6 @@
448 n32 process_mrelease sys_process_mrelease
449 n32 futex_waitv sys_futex_waitv
450 n32 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 n32 lsm_get_self_attr sys_lsm_get_self_attr
+452 n32 lsm_list_modules sys_lsm_list_modules
+453 n32 lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 3f1886ad9d80..8492aa4a771f 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -365,3 +365,6 @@
448 n64 process_mrelease sys_process_mrelease
449 n64 futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 n64 lsm_get_self_attr sys_lsm_get_self_attr
+452 n64 lsm_list_modules sys_lsm_list_modules
+453 n64 lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 8f243e35a7b2..d74fd86de2a2 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -438,3 +438,6 @@
448 o32 process_mrelease sys_process_mrelease
449 o32 futex_waitv sys_futex_waitv
450 o32 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 o32 lsm_get_self_attr sys_lsm_get_self_attr
+452 o32 lsm_list_modules sys_lsm_list_modules
+453 032 lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 0e42fceb2d5e..d1a5f3120d6c 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -448,3 +448,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index a0be127475b1..a414fe8c069b 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -537,3 +537,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 nospu set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 799147658dee..96b7e6b72747 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -453,3 +453,6 @@
448 common process_mrelease sys_process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 2de85c977f54..1a75a599bb55 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -453,3 +453,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 4398cc6fb68d..80b165091f6f 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -496,3 +496,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 320480a8db4f..130f9feb9eb9 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -455,3 +455,6 @@
448 i386 process_mrelease sys_process_mrelease
449 i386 futex_waitv sys_futex_waitv
450 i386 set_mempolicy_home_node sys_set_mempolicy_home_node
+451 i386 lsm_get_self_attr sys_lsm_get_self_attr
+452 i386 lsm_list_modules sys_lsm_list_modules
+453 i386 lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index c84d12608cd2..96dd45bc5988 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -372,6 +372,9 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
#
# 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 52c94ab5c205..2610aba19802 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -421,3 +421,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 45fa180cc56a..93f89fb06ef5 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -886,8 +886,17 @@ __SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
+#define __NR_lsm_get_self_attr 451
+__SYSCALL(__NR_lsm_get_self_attr, sys_lsm_get_self_attr)
+
+#define __NR_lsm_list_modules 452
+__SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
+
+#define __NR_lsm_set_self_attr 453
+__SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr)
+
#undef __NR_syscalls
-#define __NR_syscalls 451
+#define __NR_syscalls 454
/*
* 32 bit systems traditionally used different
diff --git a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
index 3f1886ad9d80..8492aa4a771f 100644
--- a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
+++ b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
@@ -365,3 +365,6 @@
448 n64 process_mrelease sys_process_mrelease
449 n64 futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 n64 lsm_get_self_attr sys_lsm_get_self_attr
+452 n64 lsm_list_modules sys_lsm_list_modules
+453 n64 lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index a0be127475b1..a414fe8c069b 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
@@ -537,3 +537,6 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 nospu set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
index 799147658dee..f9257e040109 100644
--- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
@@ -453,3 +453,6 @@
448 common process_mrelease sys_process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr
diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
index c84d12608cd2..96dd45bc5988 100644
--- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
@@ -372,6 +372,9 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_get_self_attr sys_lsm_get_self_attr
+452 common lsm_list_modules sys_lsm_list_modules
+453 common lsm_set_self_attr sys_lsm_set_self_attr
#
# Due to a historical design error, certain syscalls are numbered differently
--
2.39.2
Add hooks for setselfattr and getselfattr. These hooks are not very
different from their setprocattr and getprocattr equivalents, and
much of the code is shared.
Signed-off-by: Casey Schaufler <[email protected]>
Cc: [email protected]
Cc: Paul Moore <[email protected]>
---
security/selinux/hooks.c | 154 +++++++++++++++++++++++++++++++--------
1 file changed, 124 insertions(+), 30 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 2ee92d3fb79d..e78b955e04f8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6348,8 +6348,8 @@ static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
inode_doinit_with_dentry(inode, dentry);
}
-static int selinux_getprocattr(struct task_struct *p,
- const char *name, char **value)
+static int selinux_lsm_getattr(unsigned int attr, struct task_struct *p,
+ char **value)
{
const struct task_security_struct *__tsec;
u32 sid;
@@ -6367,20 +6367,27 @@ static int selinux_getprocattr(struct task_struct *p,
goto bad;
}
- if (!strcmp(name, "current"))
+ switch (attr) {
+ case LSM_ATTR_CURRENT:
sid = __tsec->sid;
- else if (!strcmp(name, "prev"))
+ break;
+ case LSM_ATTR_PREV:
sid = __tsec->osid;
- else if (!strcmp(name, "exec"))
+ break;
+ case LSM_ATTR_EXEC:
sid = __tsec->exec_sid;
- else if (!strcmp(name, "fscreate"))
+ break;
+ case LSM_ATTR_FSCREATE:
sid = __tsec->create_sid;
- else if (!strcmp(name, "keycreate"))
+ break;
+ case LSM_ATTR_KEYCREATE:
sid = __tsec->keycreate_sid;
- else if (!strcmp(name, "sockcreate"))
+ break;
+ case LSM_ATTR_SOCKCREATE:
sid = __tsec->sockcreate_sid;
- else {
- error = -EINVAL;
+ break;
+ default:
+ error = -EOPNOTSUPP;
goto bad;
}
rcu_read_unlock();
@@ -6398,7 +6405,7 @@ static int selinux_getprocattr(struct task_struct *p,
return error;
}
-static int selinux_setprocattr(const char *name, void *value, size_t size)
+static int selinux_lsm_setattr(u64 attr, void *value, size_t size)
{
struct task_security_struct *tsec;
struct cred *new;
@@ -6409,28 +6416,36 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
/*
* Basic control over ability to set these attributes at all.
*/
- if (!strcmp(name, "exec"))
+ switch (attr) {
+ case LSM_ATTR_CURRENT:
+ error = avc_has_perm(&selinux_state,
+ mysid, mysid, SECCLASS_PROCESS,
+ PROCESS__SETCURRENT, NULL);
+ break;
+ case LSM_ATTR_EXEC:
error = avc_has_perm(&selinux_state,
mysid, mysid, SECCLASS_PROCESS,
PROCESS__SETEXEC, NULL);
- else if (!strcmp(name, "fscreate"))
+ break;
+ case LSM_ATTR_FSCREATE:
error = avc_has_perm(&selinux_state,
mysid, mysid, SECCLASS_PROCESS,
PROCESS__SETFSCREATE, NULL);
- else if (!strcmp(name, "keycreate"))
+ break;
+ case LSM_ATTR_KEYCREATE:
error = avc_has_perm(&selinux_state,
mysid, mysid, SECCLASS_PROCESS,
PROCESS__SETKEYCREATE, NULL);
- else if (!strcmp(name, "sockcreate"))
+ break;
+ case LSM_ATTR_SOCKCREATE:
error = avc_has_perm(&selinux_state,
mysid, mysid, SECCLASS_PROCESS,
PROCESS__SETSOCKCREATE, NULL);
- else if (!strcmp(name, "current"))
- error = avc_has_perm(&selinux_state,
- mysid, mysid, SECCLASS_PROCESS,
- PROCESS__SETCURRENT, NULL);
- else
- error = -EINVAL;
+ break;
+ default:
+ error = -EOPNOTSUPP;
+ break;
+ }
if (error)
return error;
@@ -6442,13 +6457,14 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
}
error = security_context_to_sid(&selinux_state, value, size,
&sid, GFP_KERNEL);
- if (error == -EINVAL && !strcmp(name, "fscreate")) {
+ if (error == -EINVAL && attr == LSM_ATTR_FSCREATE) {
if (!has_cap_mac_admin(true)) {
struct audit_buffer *ab;
size_t audit_size;
- /* We strip a nul only if it is at the end, otherwise the
- * context contains a nul and we should audit that */
+ /* We strip a nul only if it is at the end,
+ * otherwise the context contains a nul and
+ * we should audit that */
if (str[size - 1] == '\0')
audit_size = size - 1;
else
@@ -6459,7 +6475,8 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
if (!ab)
return error;
audit_log_format(ab, "op=fscreate invalid_context=");
- audit_log_n_untrustedstring(ab, value, audit_size);
+ audit_log_n_untrustedstring(ab, value,
+ audit_size);
audit_log_end(ab);
return error;
@@ -6483,11 +6500,11 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
checks and may_create for the file creation checks. The
operation will then fail if the context is not permitted. */
tsec = selinux_cred(new);
- if (!strcmp(name, "exec")) {
+ if (attr == LSM_ATTR_EXEC) {
tsec->exec_sid = sid;
- } else if (!strcmp(name, "fscreate")) {
+ } else if (attr == LSM_ATTR_FSCREATE) {
tsec->create_sid = sid;
- } else if (!strcmp(name, "keycreate")) {
+ } else if (attr == LSM_ATTR_KEYCREATE) {
if (sid) {
error = avc_has_perm(&selinux_state, mysid, sid,
SECCLASS_KEY, KEY__CREATE, NULL);
@@ -6495,9 +6512,9 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
goto abort_change;
}
tsec->keycreate_sid = sid;
- } else if (!strcmp(name, "sockcreate")) {
+ } else if (attr == LSM_ATTR_SOCKCREATE) {
tsec->sockcreate_sid = sid;
- } else if (!strcmp(name, "current")) {
+ } else if (attr == LSM_ATTR_CURRENT) {
error = -EINVAL;
if (sid == 0)
goto abort_change;
@@ -6542,6 +6559,81 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
return error;
}
+static int selinux_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t *size, u32 flags)
+{
+ char *value;
+ size_t total_len;
+ int len;
+ int rc;
+
+ len = selinux_lsm_getattr(attr, current, &value);
+ if (len < 0)
+ return len;
+
+ total_len = ALIGN(struct_size(ctx, ctx, len), 8);
+
+ if (total_len > *size)
+ rc = -E2BIG;
+ else if (ctx)
+ rc = lsm_fill_user_ctx(ctx, value, len, LSM_ID_SELINUX, 0);
+ else
+ rc = 1;
+
+ *size = total_len;
+ if (rc < 0)
+ return rc;
+ return 1;
+}
+
+static int selinux_setselfattr(unsigned int __user attr,
+ struct lsm_ctx __user *ctx, size_t __user size,
+ u32 __user flags)
+{
+ struct lsm_ctx *lctx;
+ int rc;
+
+ lctx = kmalloc(size, GFP_KERNEL);
+ if (lctx == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(lctx, ctx, size))
+ rc = -EFAULT;
+ else if (lctx->ctx_len > size)
+ rc = -EINVAL;
+ else
+ rc = selinux_lsm_setattr(attr, lctx->ctx, lctx->ctx_len);
+
+ kfree(lctx);
+ if (rc > 0)
+ return 0;
+ return rc;
+}
+
+static int selinux_getprocattr(struct task_struct *p,
+ const char *name, char **value)
+{
+ unsigned int attr = lsm_name_to_attr(name);
+ int rc;
+
+ if (attr) {
+ rc = selinux_lsm_getattr(attr, p, value);
+ if (rc != -EOPNOTSUPP)
+ return rc;
+ }
+
+ return -EINVAL;
+}
+
+static int selinux_setprocattr(const char *name, void *value, size_t size)
+{
+ int attr = lsm_name_to_attr(name);
+
+ if (attr)
+ return selinux_lsm_setattr(attr, value, size);
+ return -EINVAL;
+}
+
static int selinux_ismaclabel(const char *name)
{
return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0);
@@ -7183,6 +7275,8 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(d_instantiate, selinux_d_instantiate),
+ LSM_HOOK_INIT(getselfattr, selinux_getselfattr),
+ LSM_HOOK_INIT(setselfattr, selinux_setselfattr),
LSM_HOOK_INIT(getprocattr, selinux_getprocattr),
LSM_HOOK_INIT(setprocattr, selinux_setprocattr),
--
2.39.2
Add selftests for the three system calls supporting the LSM
infrastructure.
Signed-off-by: Casey Schaufler <[email protected]>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/lsm/Makefile | 12 +
tools/testing/selftests/lsm/config | 2 +
.../selftests/lsm/lsm_get_self_attr_test.c | 270 ++++++++++++++++++
.../selftests/lsm/lsm_list_modules_test.c | 153 ++++++++++
.../selftests/lsm/lsm_set_self_attr_test.c | 70 +++++
6 files changed, 508 insertions(+)
create mode 100644 tools/testing/selftests/lsm/Makefile
create mode 100644 tools/testing/selftests/lsm/config
create mode 100644 tools/testing/selftests/lsm/lsm_get_self_attr_test.c
create mode 100644 tools/testing/selftests/lsm/lsm_list_modules_test.c
create mode 100644 tools/testing/selftests/lsm/lsm_set_self_attr_test.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 13a6837a0c6b..b18d133a1141 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -38,6 +38,7 @@ TARGETS += landlock
TARGETS += lib
TARGETS += livepatch
TARGETS += lkdtm
+TARGETS += lsm
TARGETS += membarrier
TARGETS += memfd
TARGETS += memory-hotplug
diff --git a/tools/testing/selftests/lsm/Makefile b/tools/testing/selftests/lsm/Makefile
new file mode 100644
index 000000000000..f39a75212b78
--- /dev/null
+++ b/tools/testing/selftests/lsm/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# First run: make -C ../../../.. headers_install
+
+CFLAGS += -Wall -O2 $(KHDR_INCLUDES)
+
+TEST_GEN_PROGS := lsm_get_self_attr_test lsm_list_modules_test \
+ lsm_set_self_attr_test
+
+include ../lib.mk
+
+$(TEST_GEN_PROGS):
diff --git a/tools/testing/selftests/lsm/config b/tools/testing/selftests/lsm/config
new file mode 100644
index 000000000000..afb887715f64
--- /dev/null
+++ b/tools/testing/selftests/lsm/config
@@ -0,0 +1,2 @@
+CONFIG_SYSFS=y
+CONFIG_SECURITY=y
diff --git a/tools/testing/selftests/lsm/lsm_get_self_attr_test.c b/tools/testing/selftests/lsm/lsm_get_self_attr_test.c
new file mode 100644
index 000000000000..a62524b17bf7
--- /dev/null
+++ b/tools/testing/selftests/lsm/lsm_get_self_attr_test.c
@@ -0,0 +1,270 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Linux Security Module infrastructure tests
+ * Tests for the lsm_get_self_attr system call
+ *
+ * Copyright © 2022 Casey Schaufler <[email protected]>
+ * Copyright © 2022 Intel Corporation
+ */
+
+#define _GNU_SOURCE
+#include <linux/lsm.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "../kselftest_harness.h"
+
+#define PROCATTR "/proc/self/attr/"
+
+static int read_proc_attr(const char *attr, char *value, __kernel_size_t size)
+{
+ int fd;
+ int len;
+ char *path;
+
+ len = strlen(PROCATTR) + strlen(attr) + 1;
+ path = calloc(len, 1);
+ if (path == NULL)
+ return -1;
+ sprintf(path, "%s%s", PROCATTR, attr);
+
+ fd = open(path, O_RDONLY);
+ free(path);
+
+ if (fd < 0)
+ return -1;
+ len = read(fd, value, size);
+ if (len <= 0)
+ return -1;
+ close(fd);
+
+ path = strchr(value, '\n');
+ if (path)
+ *path = '\0';
+
+ return 0;
+}
+
+static struct lsm_ctx *next_ctx(struct lsm_ctx *ctxp)
+{
+ void *vp;
+
+ vp = (void *)ctxp + sizeof(*ctxp) + ctxp->ctx_len;
+ return (struct lsm_ctx *)vp;
+}
+
+TEST(size_null_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+
+ ASSERT_NE(NULL, ctx);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ NULL, 0));
+ ASSERT_EQ(EINVAL, errno);
+
+ free(ctx);
+}
+
+TEST(ctx_null_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(-1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, NULL,
+ &size, 0));
+ ASSERT_NE(1, size);
+}
+
+TEST(size_too_small_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+ __kernel_size_t size = 1;
+
+ ASSERT_NE(NULL, ctx);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ &size, 0));
+ ASSERT_EQ(E2BIG, errno);
+ ASSERT_NE(1, size);
+
+ free(ctx);
+}
+
+TEST(flags_zero_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(NULL, ctx);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ &size, 1));
+ ASSERT_EQ(EINVAL, errno);
+ ASSERT_EQ(page_size, size);
+
+ free(ctx);
+}
+
+TEST(flags_overset_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(NULL, ctx);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_get_self_attr,
+ LSM_ATTR_CURRENT | LSM_ATTR_PREV, ctx, &size, 0));
+ ASSERT_EQ(EOPNOTSUPP, errno);
+
+ free(ctx);
+}
+
+TEST(basic_lsm_get_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ __kernel_size_t size = page_size;
+ struct lsm_ctx *ctx = calloc(page_size, 1);
+ struct lsm_ctx *tctx = NULL;
+ __u64 *syscall_lsms = calloc(page_size, 1);
+ char *attr = calloc(page_size, 1);
+ int cnt_current = 0;
+ int cnt_exec = 0;
+ int cnt_fscreate = 0;
+ int cnt_keycreate = 0;
+ int cnt_prev = 0;
+ int cnt_sockcreate = 0;
+ int lsmcount;
+ int count;
+ int i;
+
+ ASSERT_NE(NULL, ctx);
+ ASSERT_NE(NULL, syscall_lsms);
+
+ lsmcount = syscall(__NR_lsm_list_modules, syscall_lsms, &size, 0);
+ ASSERT_LE(1, lsmcount);
+
+ for (i = 0; i < lsmcount; i++) {
+ switch (syscall_lsms[i]) {
+ case LSM_ID_SELINUX:
+ cnt_current++;
+ cnt_exec++;
+ cnt_fscreate++;
+ cnt_keycreate++;
+ cnt_prev++;
+ cnt_sockcreate++;
+ break;
+ case LSM_ID_SMACK:
+ cnt_current++;
+ break;
+ case LSM_ID_APPARMOR:
+ cnt_current++;
+ cnt_exec++;
+ cnt_prev++;
+ break;
+ default:
+ break;
+ }
+ }
+
+ if (cnt_current) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ &size, 0);
+ ASSERT_EQ(cnt_current, count);
+ tctx = ctx;
+ ASSERT_EQ(0, read_proc_attr("current", attr, page_size));
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+ if (cnt_exec) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_EXEC, ctx,
+ &size, 0);
+ ASSERT_GE(cnt_exec, count);
+ if (count > 0) {
+ tctx = ctx;
+ if (read_proc_attr("exec", attr, page_size) == 0)
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ }
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+ if (cnt_fscreate) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_FSCREATE, ctx,
+ &size, 0);
+ ASSERT_GE(cnt_fscreate, count);
+ if (count > 0) {
+ tctx = ctx;
+ if (read_proc_attr("fscreate", attr, page_size) == 0)
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ }
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+ if (cnt_keycreate) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_KEYCREATE, ctx,
+ &size, 0);
+ ASSERT_GE(cnt_keycreate, count);
+ if (count > 0) {
+ tctx = ctx;
+ if (read_proc_attr("keycreate", attr, page_size) == 0)
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ }
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+ if (cnt_prev) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_PREV, ctx,
+ &size, 0);
+ ASSERT_GE(cnt_prev, count);
+ if (count > 0) {
+ tctx = ctx;
+ ASSERT_EQ(0, read_proc_attr("prev", attr, page_size));
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+ }
+ if (cnt_sockcreate) {
+ size = page_size;
+ count = syscall(__NR_lsm_get_self_attr, LSM_ATTR_SOCKCREATE,
+ ctx, &size, 0);
+ ASSERT_GE(cnt_sockcreate, count);
+ if (count > 0) {
+ tctx = ctx;
+ if (read_proc_attr("sockcreate", attr, page_size) == 0)
+ ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr));
+ }
+ for (i = 1; i < count; i++) {
+ tctx = next_ctx(tctx);
+ ASSERT_NE(0, strcmp((char *)tctx->ctx, attr));
+ }
+ }
+
+ free(ctx);
+ free(attr);
+ free(syscall_lsms);
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/lsm/lsm_list_modules_test.c b/tools/testing/selftests/lsm/lsm_list_modules_test.c
new file mode 100644
index 000000000000..871d516a7d7d
--- /dev/null
+++ b/tools/testing/selftests/lsm/lsm_list_modules_test.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Linux Security Module infrastructure tests
+ * Tests for the lsm_list_modules system call
+ *
+ * Copyright © 2022 Casey Schaufler <[email protected]>
+ * Copyright © 2022 Intel Corporation
+ */
+
+#define _GNU_SOURCE
+#include <linux/lsm.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "../kselftest_harness.h"
+
+static int read_sysfs_lsms(char *lsms, __kernel_size_t size)
+{
+ FILE *fp;
+
+ fp = fopen("/sys/kernel/security/lsm", "r");
+ if (fp == NULL)
+ return -1;
+ if (fread(lsms, 1, size, fp) <= 0)
+ return -1;
+ fclose(fp);
+ return 0;
+}
+
+TEST(size_null_lsm_list_modules)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *syscall_lsms = calloc(page_size, 1);
+
+ ASSERT_NE(NULL, syscall_lsms);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_list_modules, syscall_lsms, NULL, 0));
+ ASSERT_EQ(EFAULT, errno);
+
+ free(syscall_lsms);
+}
+
+TEST(ids_null_lsm_list_modules)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ __kernel_size_t size = page_size;
+
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_list_modules, NULL, &size, 0));
+ ASSERT_EQ(EFAULT, errno);
+ ASSERT_NE(1, size);
+}
+
+TEST(size_too_small_lsm_list_modules)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *syscall_lsms = calloc(page_size, 1);
+ __kernel_size_t size = 1;
+
+ ASSERT_NE(NULL, syscall_lsms);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_list_modules, syscall_lsms, &size, 0));
+ ASSERT_EQ(E2BIG, errno);
+ ASSERT_NE(1, size);
+
+ free(syscall_lsms);
+}
+
+TEST(flags_set_lsm_list_modules)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *syscall_lsms = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(NULL, syscall_lsms);
+ errno = 0;
+ ASSERT_EQ(-1, syscall(__NR_lsm_list_modules, syscall_lsms, &size, 7));
+ ASSERT_EQ(EINVAL, errno);
+ ASSERT_EQ(page_size, size);
+
+ free(syscall_lsms);
+}
+
+TEST(correct_lsm_list_modules)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ __kernel_size_t size = page_size;
+ __u64 *syscall_lsms = calloc(page_size, 1);
+ char *sysfs_lsms = calloc(page_size, 1);
+ char *name;
+ char *cp;
+ int count;
+ int i;
+
+ ASSERT_NE(NULL, sysfs_lsms);
+ ASSERT_NE(NULL, syscall_lsms);
+ ASSERT_EQ(0, read_sysfs_lsms(sysfs_lsms, page_size));
+
+ count = syscall(__NR_lsm_list_modules, syscall_lsms, &size, 0);
+ ASSERT_LE(1, count);
+ cp = sysfs_lsms;
+ for (i = 0; i < count; i++) {
+ switch (syscall_lsms[i]) {
+ case LSM_ID_CAPABILITY:
+ name = "capability";
+ break;
+ case LSM_ID_SELINUX:
+ name = "selinux";
+ break;
+ case LSM_ID_SMACK:
+ name = "smack";
+ break;
+ case LSM_ID_TOMOYO:
+ name = "tomoyo";
+ break;
+ case LSM_ID_IMA:
+ name = "ima";
+ break;
+ case LSM_ID_APPARMOR:
+ name = "apparmor";
+ break;
+ case LSM_ID_YAMA:
+ name = "yama";
+ break;
+ case LSM_ID_LOADPIN:
+ name = "loadpin";
+ break;
+ case LSM_ID_SAFESETID:
+ name = "safesetid";
+ break;
+ case LSM_ID_LOCKDOWN:
+ name = "lockdown";
+ break;
+ case LSM_ID_BPF:
+ name = "bpf";
+ break;
+ case LSM_ID_LANDLOCK:
+ name = "landlock";
+ break;
+ default:
+ name = "INVALID";
+ break;
+ }
+ ASSERT_EQ(0, strncmp(cp, name, strlen(name)));
+ cp += strlen(name) + 1;
+ }
+
+ free(sysfs_lsms);
+ free(syscall_lsms);
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/lsm/lsm_set_self_attr_test.c b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c
new file mode 100644
index 000000000000..ca538a703168
--- /dev/null
+++ b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Linux Security Module infrastructure tests
+ * Tests for the lsm_set_self_attr system call
+ *
+ * Copyright © 2022 Casey Schaufler <[email protected]>
+ * Copyright © 2022 Intel Corporation
+ */
+
+#define _GNU_SOURCE
+#include <linux/lsm.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include "../kselftest_harness.h"
+
+TEST(ctx_null_lsm_set_self_attr)
+{
+ ASSERT_EQ(-1, syscall(__NR_lsm_set_self_attr, LSM_ATTR_CURRENT, NULL,
+ sizeof(struct lsm_ctx), 0));
+}
+
+TEST(size_too_small_lsm_set_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ struct lsm_ctx *ctx = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(NULL, ctx);
+ ASSERT_GE(1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ &size, 0));
+ ASSERT_EQ(-1, syscall(__NR_lsm_set_self_attr, LSM_ATTR_CURRENT, ctx, 1,
+ 0));
+
+ free(ctx);
+}
+
+TEST(flags_zero_lsm_set_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+
+ ASSERT_NE(NULL, ctx);
+ ASSERT_GE(1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, ctx,
+ &size, 0));
+ ASSERT_EQ(-1, syscall(__NR_lsm_set_self_attr, LSM_ATTR_CURRENT, ctx,
+ size, 1));
+
+ free(ctx);
+}
+
+TEST(flags_overset_lsm_set_self_attr)
+{
+ const long page_size = sysconf(_SC_PAGESIZE);
+ char *ctx = calloc(page_size, 1);
+ __kernel_size_t size = page_size;
+ struct lsm_ctx *tctx = (struct lsm_ctx *)ctx;
+
+ ASSERT_NE(NULL, ctx);
+ ASSERT_GE(1, syscall(__NR_lsm_get_self_attr, LSM_ATTR_CURRENT, tctx,
+ &size, 0));
+ ASSERT_EQ(-1, syscall(__NR_lsm_set_self_attr,
+ LSM_ATTR_CURRENT | LSM_ATTR_PREV, tctx, size, 0));
+
+ free(ctx);
+}
+
+TEST_HARNESS_MAIN
--
2.39.2
As LSMs are registered add their lsm_id pointers to a table.
This will be used later for attribute reporting.
Determine the number of possible security modules based on
their respective CONFIG options. This allows the number to be
known at build time. This allows data structures and tables
to use the constant.
Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
---
include/linux/security.h | 2 ++
security/security.c | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/include/linux/security.h b/include/linux/security.h
index 5984d0d550b4..e70fc863b04a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -138,6 +138,8 @@ enum lockdown_reason {
};
extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
+extern u32 lsm_active_cnt;
+extern struct lsm_id *lsm_idlist[];
/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
diff --git a/security/security.c b/security/security.c
index a482c6048df9..e390001a32c9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -35,6 +35,25 @@
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
+/*
+ * How many LSMs are built into the kernel as determined at
+ * build time. Used to determine fixed array sizes.
+ * The capability module is accounted for by CONFIG_SECURITY
+ */
+#define LSM_CONFIG_COUNT ( \
+ (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0))
+
/*
* These are descriptions of the reasons that can be passed to the
* security_locked_down() LSM hook. Placing this array here allows
@@ -244,6 +263,12 @@ static void __init initialize_lsm(struct lsm_info *lsm)
}
}
+/*
+ * Current index to use while initializing the lsm id list.
+ */
+u32 lsm_active_cnt __lsm_ro_after_init;
+struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT] __lsm_ro_after_init;
+
/* Populate ordered LSMs list from comma-separated LSM name list. */
static void __init ordered_lsm_parse(const char *order, const char *origin)
{
@@ -513,6 +538,17 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
{
int i;
+ if (lsm_active_cnt >= LSM_CONFIG_COUNT)
+ panic("%s Too many LSMs registered.\n", __func__);
+ /*
+ * A security module may call security_add_hooks() more
+ * than once during initialization, and LSM initialization
+ * is serialized. Landlock is one such case.
+ * Look at the previous entry, if there is one, for duplication.
+ */
+ if (lsm_active_cnt == 0 || lsm_idlist[lsm_active_cnt - 1] != lsmid)
+ lsm_idlist[lsm_active_cnt++] = lsmid;
+
for (i = 0; i < count; i++) {
hooks[i].lsmid = lsmid;
hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
--
2.39.2
Add lsm_name_to_attr(), which translates a text string to a
LSM_ATTR value if one is available.
Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
the trailing attribute value. The .len value is padded to a multiple
of 64 bits for alignment.
All are used in module specific components of LSM system calls.
Signed-off-by: Casey Schaufler <[email protected]>
---
include/linux/security.h | 13 ++++++++++++
security/lsm_syscalls.c | 24 ++++++++++++++++++++++
security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 81 insertions(+)
diff --git a/include/linux/security.h b/include/linux/security.h
index 806bff425af9..36ace59f9171 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -263,6 +263,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb);
/* prototypes */
extern int security_init(void);
extern int early_security_init(void);
+extern u64 lsm_name_to_attr(const char *name);
/* Security operations */
int security_binder_set_context_mgr(const struct cred *mgr);
@@ -491,6 +492,8 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
int security_locked_down(enum lockdown_reason what);
+int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags);
#else /* CONFIG_SECURITY */
static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
@@ -508,6 +511,11 @@ static inline int unregister_blocking_lsm_notifier(struct notifier_block *nb)
return 0;
}
+static inline u64 lsm_name_to_attr(const char *name)
+{
+ return LSM_ATTR_UNDEF;
+}
+
static inline void security_free_mnt_opts(void **mnt_opts)
{
}
@@ -1420,6 +1428,11 @@ static inline int security_locked_down(enum lockdown_reason what)
{
return 0;
}
+static inline int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_SECURITY */
#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index b89cccb2f123..0b225adfe5f7 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -17,6 +17,30 @@
#include <linux/lsm_hooks.h>
#include <uapi/linux/lsm.h>
+/**
+ * lsm_name_to_attr - map an LSM attribute name to its ID
+ * @name: name of the attribute
+ *
+ * Returns the LSM attribute value associated with @name, or 0 if
+ * there is no mapping.
+ */
+u64 lsm_name_to_attr(const char *name)
+{
+ if (!strcmp(name, "current"))
+ return LSM_ATTR_CURRENT;
+ if (!strcmp(name, "exec"))
+ return LSM_ATTR_EXEC;
+ if (!strcmp(name, "fscreate"))
+ return LSM_ATTR_FSCREATE;
+ if (!strcmp(name, "keycreate"))
+ return LSM_ATTR_KEYCREATE;
+ if (!strcmp(name, "prev"))
+ return LSM_ATTR_PREV;
+ if (!strcmp(name, "sockcreate"))
+ return LSM_ATTR_SOCKCREATE;
+ return LSM_ATTR_UNDEF;
+}
+
/**
* sys_lsm_set_self_attr - Set current task's security module attribute
* @attr: which attribute to set
diff --git a/security/security.c b/security/security.c
index 94b78bfd06b9..8c877d639cae 100644
--- a/security/security.c
+++ b/security/security.c
@@ -761,6 +761,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
return 0;
}
+/**
+ * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
+ * @ctx: an LSM context to be filled
+ * @context: the new context value
+ * @context_size: the size of the new context value
+ * @id: LSM id
+ * @flags: LSM defined flags
+ *
+ * Fill all of the fields in a user space lsm_ctx structure.
+ * Caller is assumed to have verified that @ctx has enough space
+ * for @context.
+ *
+ * The total length is padded to a multiple of 64 bits to
+ * accomodate possible alignment issues.
+ *
+ * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
+ * if memory can't be allocated.
+ */
+int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags)
+{
+ struct lsm_ctx *lctx;
+ size_t locallen = ALIGN(struct_size(lctx, ctx, context_size), 8);
+ int rc = 0;
+
+ lctx = kzalloc(locallen, GFP_KERNEL);
+ if (lctx == NULL)
+ return -ENOMEM;
+
+ lctx->id = id;
+ lctx->flags = flags;
+ lctx->ctx_len = context_size;
+ lctx->len = locallen;
+
+ memcpy(lctx->ctx, context, context_size);
+
+ if (copy_to_user(ctx, lctx, locallen))
+ rc = -EFAULT;
+
+ kfree(lctx);
+
+ return rc;
+}
+
/*
* The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
* can be accessed with:
--
2.39.2
Add hooks for setselfattr and getselfattr. These hooks are not very
different from their setprocattr and getprocattr equivalents, and
much of the code is shared.
Signed-off-by: Casey Schaufler <[email protected]>
Cc: John Johansen <[email protected]>
---
security/apparmor/include/procattr.h | 2 +-
security/apparmor/lsm.c | 102 +++++++++++++++++++++++++--
security/apparmor/procattr.c | 10 +--
3 files changed, 103 insertions(+), 11 deletions(-)
diff --git a/security/apparmor/include/procattr.h b/security/apparmor/include/procattr.h
index 31689437e0e1..03dbfdb2f2c0 100644
--- a/security/apparmor/include/procattr.h
+++ b/security/apparmor/include/procattr.h
@@ -11,7 +11,7 @@
#ifndef __AA_PROCATTR_H
#define __AA_PROCATTR_H
-int aa_getprocattr(struct aa_label *label, char **string);
+int aa_getprocattr(struct aa_label *label, char **string, bool newline);
int aa_setprocattr_changehat(char *args, size_t size, int flags);
#endif /* __AA_PROCATTR_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index d7f22b0cf03f..6e77e885e167 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -630,6 +630,54 @@ static int apparmor_sb_pivotroot(const struct path *old_path,
return error;
}
+static int apparmor_getselfattr(unsigned int attr, struct lsm_ctx __user *lx,
+ size_t *size, u32 flags)
+{
+ int error = -ENOENT;
+ struct aa_task_ctx *ctx = task_ctx(current);
+ struct aa_label *label = NULL;
+ size_t total_len = 0;
+ char *value;
+
+ switch (attr) {
+ case LSM_ATTR_CURRENT:
+ label = aa_get_newest_label(cred_label(current_cred()));
+ break;
+ case LSM_ATTR_PREV:
+ if (ctx->previous)
+ label = aa_get_newest_label(ctx->previous);
+ break;
+ case LSM_ATTR_EXEC:
+ if (ctx->onexec)
+ label = aa_get_newest_label(ctx->onexec);
+ break;
+ default:
+ error = -EOPNOTSUPP;
+ break;
+ }
+
+ if (label) {
+ error = aa_getprocattr(label, &value, false);
+ if (error > 0) {
+ total_len = ALIGN(struct_size(lx, ctx, error), 8);
+ if (total_len > *size)
+ error = -E2BIG;
+ else if (lx)
+ error = lsm_fill_user_ctx(lx, value, error,
+ LSM_ID_APPARMOR, 0);
+ else
+ error = 1;
+ }
+ }
+
+ aa_put_label(label);
+
+ *size = total_len;
+ if (error < 0)
+ return error;
+ return 1;
+}
+
static int apparmor_getprocattr(struct task_struct *task, const char *name,
char **value)
{
@@ -649,7 +697,7 @@ static int apparmor_getprocattr(struct task_struct *task, const char *name,
error = -EINVAL;
if (label)
- error = aa_getprocattr(label, value);
+ error = aa_getprocattr(label, value, true);
aa_put_label(label);
put_cred(cred);
@@ -657,8 +705,7 @@ static int apparmor_getprocattr(struct task_struct *task, const char *name,
return error;
}
-static int apparmor_setprocattr(const char *name, void *value,
- size_t size)
+static int do_setattr(u64 attr, void *value, size_t size)
{
char *command, *largs = NULL, *args = value;
size_t arg_size;
@@ -689,7 +736,7 @@ static int apparmor_setprocattr(const char *name, void *value,
goto out;
arg_size = size - (args - (largs ? largs : (char *) value));
- if (strcmp(name, "current") == 0) {
+ if (attr == LSM_ATTR_CURRENT) {
if (strcmp(command, "changehat") == 0) {
error = aa_setprocattr_changehat(args, arg_size,
AA_CHANGE_NOFLAGS);
@@ -704,7 +751,7 @@ static int apparmor_setprocattr(const char *name, void *value,
error = aa_change_profile(args, AA_CHANGE_STACK);
} else
goto fail;
- } else if (strcmp(name, "exec") == 0) {
+ } else if (attr == LSM_ATTR_EXEC) {
if (strcmp(command, "exec") == 0)
error = aa_change_profile(args, AA_CHANGE_ONEXEC);
else if (strcmp(command, "stack") == 0)
@@ -724,13 +771,54 @@ static int apparmor_setprocattr(const char *name, void *value,
fail:
aad(&sa)->label = begin_current_label_crit_section();
- aad(&sa)->info = name;
+ if (attr == LSM_ATTR_CURRENT)
+ aad(&sa)->info = "current";
+ else if (attr == LSM_ATTR_EXEC)
+ aad(&sa)->info = "exec";
+ else
+ aad(&sa)->info = "invalid";
aad(&sa)->error = error = -EINVAL;
aa_audit_msg(AUDIT_APPARMOR_DENIED, &sa, NULL);
end_current_label_crit_section(aad(&sa)->label);
goto out;
}
+static int apparmor_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
+ size_t size, u32 flags)
+{
+ struct lsm_ctx *lctx;
+ int rc;
+
+ if (attr != LSM_ATTR_CURRENT && attr != LSM_ATTR_EXEC)
+ return -EOPNOTSUPP;
+
+ lctx = kmalloc(size, GFP_KERNEL);
+ if (lctx == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(lctx, ctx, size))
+ rc = -EFAULT;
+ else if (lctx->ctx_len > size)
+ rc = -EINVAL;
+ else
+ rc = do_setattr(attr, lctx->ctx, lctx->ctx_len);
+
+ kfree(lctx);
+ if (rc > 0)
+ return 0;
+ return rc;
+}
+
+static int apparmor_setprocattr(const char *name, void *value,
+ size_t size)
+{
+ int attr = lsm_name_to_attr(name);
+
+ if (attr)
+ return do_setattr(attr, value, size);
+ return -EINVAL;
+}
+
/**
* apparmor_bprm_committing_creds - do task cleanup on committing new creds
* @bprm: binprm for the exec (NOT NULL)
@@ -1253,6 +1341,8 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(file_lock, apparmor_file_lock),
LSM_HOOK_INIT(file_truncate, apparmor_file_truncate),
+ LSM_HOOK_INIT(getselfattr, apparmor_getselfattr),
+ LSM_HOOK_INIT(setselfattr, apparmor_setselfattr),
LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
diff --git a/security/apparmor/procattr.c b/security/apparmor/procattr.c
index 197d41f9c32b..e3857e3d7c6c 100644
--- a/security/apparmor/procattr.c
+++ b/security/apparmor/procattr.c
@@ -20,6 +20,7 @@
* aa_getprocattr - Return the label information for @label
* @label: the label to print label info about (NOT NULL)
* @string: Returns - string containing the label info (NOT NULL)
+ * @newline: indicates that a newline should be added
*
* Requires: label != NULL && string != NULL
*
@@ -27,7 +28,7 @@
*
* Returns: size of string placed in @string else error code on failure
*/
-int aa_getprocattr(struct aa_label *label, char **string)
+int aa_getprocattr(struct aa_label *label, char **string, bool newline)
{
struct aa_ns *ns = labels_ns(label);
struct aa_ns *current_ns = aa_get_current_ns();
@@ -57,11 +58,12 @@ int aa_getprocattr(struct aa_label *label, char **string)
return len;
}
- (*string)[len] = '\n';
- (*string)[len + 1] = 0;
+ if (newline)
+ (*string)[len++] = '\n';
+ (*string)[len] = 0;
aa_put_ns(current_ns);
- return len + 1;
+ return len;
}
/**
--
2.39.2
Hi Casey,
kernel test robot noticed the following build errors:
[auto build test ERROR on tip/perf/core]
[also build test ERROR on acme/perf/core shuah-kselftest/next shuah-kselftest/fixes v6.3]
[cannot apply to linus/master next-20230428]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230429-053458
base: tip/perf/core
patch link: https://lore.kernel.org/r/20230428203417.159874-8-casey%40schaufler-ca.com
patch subject: [PATCH v10 07/11] LSM: Helpers for attribute names and filling lsm_ctx
config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20230429/[email protected]/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/9830f4776196e33bee604b8ce3339177f8fd37f8
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230429-053458
git checkout 9830f4776196e33bee604b8ce3339177f8fd37f8
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=um SUBARCH=i386 olddefconfig
make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
In file included from include/linux/perf_event.h:62,
from include/linux/trace_events.h:10,
from include/trace/syscall.h:7,
from include/linux/syscalls.h:89,
from init/main.c:21:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
init/main.c: At top level:
init/main.c:775:20: warning: no previous prototype for 'arch_post_acpi_subsys_init' [-Wmissing-prototypes]
775 | void __init __weak arch_post_acpi_subsys_init(void) { }
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
init/main.c:787:20: warning: no previous prototype for 'mem_encrypt_init' [-Wmissing-prototypes]
787 | void __init __weak mem_encrypt_init(void) { }
| ^~~~~~~~~~~~~~~~
init/main.c:789:20: warning: no previous prototype for 'poking_init' [-Wmissing-prototypes]
789 | void __init __weak poking_init(void) { }
| ^~~~~~~~~~~
--
In file included from init/do_mounts.c:9:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
--
In file included from include/net/scm.h:8,
from include/linux/netlink.h:9,
from include/uapi/linux/neighbour.h:6,
from include/linux/netdevice.h:46,
from include/uapi/linux/if_arp.h:27,
from include/linux/if_arp.h:23,
from arch/um/drivers/slirp_kern.c:6:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
arch/um/drivers/slirp_kern.c: At top level:
arch/um/drivers/slirp_kern.c:18:6: warning: no previous prototype for 'slirp_init' [-Wmissing-prototypes]
18 | void slirp_init(struct net_device *dev, void *data)
| ^~~~~~~~~~
--
In file included from include/linux/perf_event.h:62,
from include/linux/trace_events.h:10,
from include/trace/syscall.h:7,
from include/linux/syscalls.h:89,
from arch/x86/um/tls_32.c:8:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
arch/x86/um/tls_32.c: At top level:
arch/x86/um/tls_32.c:23:5: warning: no previous prototype for 'do_set_thread_area' [-Wmissing-prototypes]
23 | int do_set_thread_area(struct user_desc *info)
| ^~~~~~~~~~~~~~~~~~
arch/x86/um/tls_32.c:39:5: warning: no previous prototype for 'do_get_thread_area' [-Wmissing-prototypes]
39 | int do_get_thread_area(struct user_desc *info)
| ^~~~~~~~~~~~~~~~~~
arch/x86/um/tls_32.c:184:5: warning: no previous prototype for 'arch_switch_tls' [-Wmissing-prototypes]
184 | int arch_switch_tls(struct task_struct *to)
| ^~~~~~~~~~~~~~~
--
In file included from kernel/fork.c:51:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
kernel/fork.c: At top level:
kernel/fork.c:162:13: warning: no previous prototype for 'arch_release_task_struct' [-Wmissing-prototypes]
162 | void __weak arch_release_task_struct(struct task_struct *tsk)
| ^~~~~~~~~~~~~~~~~~~~~~~~
kernel/fork.c:859:20: warning: no previous prototype for 'arch_task_cache_init' [-Wmissing-prototypes]
859 | void __init __weak arch_task_cache_init(void) { }
| ^~~~~~~~~~~~~~~~~~~~
kernel/fork.c:954:12: warning: no previous prototype for 'arch_dup_task_struct' [-Wmissing-prototypes]
954 | int __weak arch_dup_task_struct(struct task_struct *dst,
| ^~~~~~~~~~~~~~~~~~~~
--
In file included from include/linux/perf_event.h:62,
from include/linux/trace_events.h:10,
from include/trace/syscall.h:7,
from include/linux/syscalls.h:89,
from kernel/exit.c:42:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
kernel/exit.c: At top level:
kernel/exit.c:1915:32: warning: no previous prototype for 'abort' [-Wmissing-prototypes]
1915 | __weak __function_aligned void abort(void)
| ^~~~~
--
In file included from include/net/scm.h:8,
from include/linux/netlink.h:9,
from include/uapi/linux/neighbour.h:6,
from include/linux/netdevice.h:46,
from include/linux/if_vlan.h:10,
from include/linux/filter.h:21,
from kernel/kallsyms.c:25:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
kernel/kallsyms.c: At top level:
kernel/kallsyms.c:663:12: warning: no previous prototype for 'arch_get_kallsym' [-Wmissing-prototypes]
663 | int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
| ^~~~~~~~~~~~~~~~
--
In file included from include/linux/fs_context.h:14,
from include/linux/pseudo_fs.h:4,
from fs/pipe.c:17:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
fs/pipe.c: At top level:
fs/pipe.c:757:15: warning: no previous prototype for 'account_pipe_buffers' [-Wmissing-prototypes]
757 | unsigned long account_pipe_buffers(struct user_struct *user,
| ^~~~~~~~~~~~~~~~~~~~
fs/pipe.c:763:6: warning: no previous prototype for 'too_many_pipe_buffers_soft' [-Wmissing-prototypes]
763 | bool too_many_pipe_buffers_soft(unsigned long user_bufs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
fs/pipe.c:770:6: warning: no previous prototype for 'too_many_pipe_buffers_hard' [-Wmissing-prototypes]
770 | bool too_many_pipe_buffers_hard(unsigned long user_bufs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
fs/pipe.c:777:6: warning: no previous prototype for 'pipe_is_unprivileged_user' [-Wmissing-prototypes]
777 | bool pipe_is_unprivileged_user(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
fs/pipe.c:1253:5: warning: no previous prototype for 'pipe_resize_ring' [-Wmissing-prototypes]
1253 | int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots)
| ^~~~~~~~~~~~~~~~
--
In file included from include/linux/perf_event.h:62,
from include/linux/trace_events.h:10,
from include/trace/syscall.h:7,
from include/linux/syscalls.h:89,
from fs/d_path.c:2:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
fs/d_path.c: At top level:
fs/d_path.c:317:7: warning: no previous prototype for 'simple_dname' [-Wmissing-prototypes]
317 | char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
| ^~~~~~~~~~~~
--
In file included from include/net/scm.h:8,
from include/linux/netlink.h:9,
from include/uapi/linux/neighbour.h:6,
from include/linux/netdevice.h:46,
from include/net/sock.h:46,
from include/linux/tcp.h:19,
from include/linux/ipv6.h:93,
from include/net/addrconf.h:52,
from lib/vsprintf.c:40:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
lib/vsprintf.c: In function 'va_format':
lib/vsprintf.c:1681:9: warning: function 'va_format' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
1681 | buf += vsnprintf(buf, end > buf ? end - buf : 0, va_fmt->fmt, va);
| ^~~
--
In file included from include/net/scm.h:8,
from include/linux/netlink.h:9,
from include/uapi/linux/neighbour.h:6,
from include/linux/netdevice.h:46,
from include/net/sock.h:46,
from include/linux/bpf-cgroup.h:11,
from net/socket.c:55:
include/linux/security.h: In function 'lsm_name_to_attr':
>> include/linux/security.h:516:16: error: 'LSM_ATTR_UNDEF' undeclared (first use in this function)
516 | return LSM_ATTR_UNDEF;
| ^~~~~~~~~~~~~~
include/linux/security.h:516:16: note: each undeclared identifier is reported only once for each function it appears in
net/socket.c: In function '__sys_getsockopt':
net/socket.c:2297:13: warning: variable 'max_optlen' set but not used [-Wunused-but-set-variable]
2297 | int max_optlen;
| ^~~~~~~~~~
..
vim +/LSM_ATTR_UNDEF +516 include/linux/security.h
513
514 static inline u64 lsm_name_to_attr(const char *name)
515 {
> 516 return LSM_ATTR_UNDEF;
517 }
518
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
Hi Casey,
kernel test robot noticed the following build errors:
[auto build test ERROR on tip/perf/core]
[also build test ERROR on acme/perf/core shuah-kselftest/next shuah-kselftest/fixes v6.3]
[cannot apply to linus/master next-20230428]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230429-053458
base: tip/perf/core
patch link: https://lore.kernel.org/r/20230428203417.159874-8-casey%40schaufler-ca.com
patch subject: [PATCH v10 07/11] LSM: Helpers for attribute names and filling lsm_ctx
config: riscv-randconfig-r003-20230428 (https://download.01.org/0day-ci/archive/20230429/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 437b7602e4a998220871de78afcb020b9c14a661)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/9830f4776196e33bee604b8ce3339177f8fd37f8
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230429-053458
git checkout 9830f4776196e33bee604b8ce3339177f8fd37f8
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv prepare
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
In file included from arch/riscv/kernel/asm-offsets.c:12:
In file included from arch/riscv/include/asm/kvm_host.h:21:
In file included from arch/riscv/include/asm/kvm_vcpu_pmu.h:12:
In file included from include/linux/perf/riscv_pmu.h:12:
In file included from include/linux/perf_event.h:62:
>> include/linux/security.h:516:9: error: use of undeclared identifier 'LSM_ATTR_UNDEF'
return LSM_ATTR_UNDEF;
^
1 error generated.
make[2]: *** [scripts/Makefile.build:114: arch/riscv/kernel/asm-offsets.s] Error 1
make[2]: Target 'prepare' not remade because of errors.
make[1]: *** [Makefile:1286: prepare0] Error 2
make[1]: Target 'prepare' not remade because of errors.
make: *** [Makefile:226: __sub-make] Error 2
make: Target 'prepare' not remade because of errors.
vim +/LSM_ATTR_UNDEF +516 include/linux/security.h
513
514 static inline u64 lsm_name_to_attr(const char *name)
515 {
> 516 return LSM_ATTR_UNDEF;
517 }
518
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
On Apr 28, 2023 Casey Schaufler <[email protected]> wrote:
>
> Create a system call lsm_get_self_attr() to provide the security
> module maintained attributes of the current process.
> Create a system call lsm_set_self_attr() to set a security
> module maintained attribute of the current process.
> Historically these attributes have been exposed to user space via
> entries in procfs under /proc/self/attr.
>
> The attribute value is provided in a lsm_ctx structure. The structure
> identifies the size of the attribute, and the attribute value. The format
> of the attribute value is defined by the security module. A flags field
> is included for LSM specific information. It is currently unused and must
> be 0. The total size of the data, including the lsm_ctx structure and any
> padding, is maintained as well.
>
> struct lsm_ctx {
> __u64 id;
> __u64 flags;
> __u64 len;
> __u64 ctx_len;
> __u8 ctx[];
> };
>
> Two new LSM hooks are used to interface with the LSMs.
> security_getselfattr() collects the lsm_ctx values from the
> LSMs that support the hook, accounting for space requirements.
> security_setselfattr() identifies which LSM the attribute is
> intended for and passes it along.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
> ---
> Documentation/userspace-api/lsm.rst | 15 ++++
> include/linux/lsm_hook_defs.h | 4 +
> include/linux/lsm_hooks.h | 9 +++
> include/linux/security.h | 19 +++++
> include/linux/syscalls.h | 5 ++
> include/uapi/linux/lsm.h | 36 +++++++++
> kernel/sys_ni.c | 4 +
> security/Makefile | 1 +
> security/lsm_syscalls.c | 55 ++++++++++++++
> security/security.c | 112 ++++++++++++++++++++++++++++
> 10 files changed, 260 insertions(+)
> create mode 100644 security/lsm_syscalls.c
...
> diff --git a/security/security.c b/security/security.c
> index 5a48b1b539e5..94b78bfd06b9 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2176,6 +2176,118 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
> }
> EXPORT_SYMBOL(security_d_instantiate);
>
> +/**
> + * security_getselfattr - Read an LSM attribute of the current process.
> + * @attr: which attribute to return
> + * @ctx: the user-space destination for the information, or NULL
> + * @size: the size of space available to receive the data
> + * @flags: special handling options. LSM_FLAG_SINGLE indicates that only
> + * attributes associated with the LSM identified in the passed @ctx be
> + * reported
> + *
> + * Returns the number of attributes found on success, negative value
> + * on error. @size is reset to the total size of the data.
> + * If @size is insufficient to contain the data -E2BIG is returned.
> + */
> +int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t __user *size, u32 flags)
> +{
> + struct security_hook_list *hp;
> + struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, };
> + u8 __user *base = (u8 __user *)ctx;
> + size_t total = 0;
> + size_t entrysize;
> + size_t left;
> + bool toobig = false;
> + int count = 0;
> + int rc;
> +
> + if (attr == 0)
> + return -EINVAL;
> + if (size == NULL)
> + return -EINVAL;
> + if (get_user(left, size))
> + return -EFAULT;
> +
> + if ((flags & LSM_FLAG_SINGLE) == LSM_FLAG_SINGLE) {
> + if (!ctx)
> + return -EINVAL;
> + if (copy_struct_from_user(&lctx, sizeof(lctx), ctx, left))
> + return -EFAULT;
> + if (lctx.id == LSM_ID_UNDEF)
> + return -EINVAL;
> + } else if (flags) {
> + return -EINVAL;
> + }
> +
> + hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) {
> + if (lctx.id != LSM_ID_UNDEF && lctx.id != hp->lsmid->id)
> + continue;
I think we're missing a copy_struct_from_user() call somewhere; how
does @lctx get populated in the non-LSM_FLAG_SINGLE case? How does
it move to the next entry in the buffer?
Am I missing something obvious? Was this code tested?
> + entrysize = left;
> + if (base)
> + ctx = (struct lsm_ctx __user *)(base + total);
> + rc = hp->hook.getselfattr(attr, ctx, &entrysize, flags);
> + if (rc == -EOPNOTSUPP) {
> + rc = 0;
> + continue;
> + }
> + if (rc == -E2BIG) {
> + toobig = true;
> + left = 0;
> + continue;
> + }
> + if (rc < 0)
> + return rc;
> +
> + left -= entrysize;
> + total += entrysize;
> + count += rc;
> + }
> + if (put_user(total, size))
> + return -EFAULT;
> + if (toobig)
> + return -E2BIG;
> + if (count == 0)
> + return LSM_RET_DEFAULT(getselfattr);
> + return count;
> +}
> +
> +/**
> + * security_setselfattr - Set an LSM attribute on the current process.
> + * @attr: which attribute to set
> + * @ctx: the user-space source for the information
> + * @size: the size of the data
> + * @flags: reserved for future use, must be 0
> + *
> + * Set an LSM attribute for the current process. The LSM, attribute
> + * and new value are included in @ctx.
> + *
> + * Returns 0 on success, -EINVAL if the input is inconsistent, -EFAULT
> + * if the user buffer is inaccessible or an LSM specific failure.
> + */
> +int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t size, u32 flags)
> +{
> + struct security_hook_list *hp;
> + struct lsm_ctx lctx;
> +
> + if (flags)
> + return -EINVAL;
Once again, I don't see a reasonable way to support setting an
attribute across multiple LSMs, but for the sake of consistency
across both the getselfattr and setselfattr syscalls, what do
people think about *requiring* the LSM_FLAG_SINGLE flag here in
the setselfattr syscalls since it can only operate on a single
LSM at a time? A zero flag value would return -EINVAL.
> + if (size < sizeof(*ctx))
> + return -EINVAL;
> + if (copy_from_user(&lctx, ctx, sizeof(*ctx)))
> + return -EFAULT;
> + if (size < lctx.len || size < lctx.ctx_len + sizeof(ctx) ||
> + lctx.len < lctx.ctx_len + sizeof(ctx))
> + return -EINVAL;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list)
> + if ((hp->lsmid->id) == lctx.id)
> + return hp->hook.setselfattr(attr, ctx, size, flags);
> +
> + return LSM_RET_DEFAULT(setselfattr);
> +}
> +
> int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
> char **value)
> {
> --
> 2.39.2
--
paul-moore.com
On Apr 28, 2023 Casey Schaufler <[email protected]> wrote:
>
> Add hooks for setselfattr and getselfattr. These hooks are not very
> different from their setprocattr and getprocattr equivalents, and
> much of the code is shared.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> Cc: [email protected]
> Cc: Paul Moore <[email protected]>
> ---
> security/selinux/hooks.c | 154 +++++++++++++++++++++++++++++++--------
> 1 file changed, 124 insertions(+), 30 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 2ee92d3fb79d..e78b955e04f8 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6542,6 +6559,81 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
> return error;
> }
>
> +static int selinux_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t *size, u32 flags)
> +{
> + char *value;
> + size_t total_len;
> + int len;
> + int rc;
> +
> + len = selinux_lsm_getattr(attr, current, &value);
> + if (len < 0)
> + return len;
> +
> + total_len = ALIGN(struct_size(ctx, ctx, len), 8);
> +
> + if (total_len > *size)
> + rc = -E2BIG;
Hmm. Since we need to calculate the aligned @total_len value in the
LSM specific code, perhaps it doesn't make sense to also do the
alignment in lsm_fill_user_ctx(). My apologies, I know I was the one
who suggested doing the alignment in a common place previously.
> + else if (ctx)
> + rc = lsm_fill_user_ctx(ctx, value, len, LSM_ID_SELINUX, 0);
> + else
> + rc = 1;
> +
> + *size = total_len;
> + if (rc < 0)
> + return rc;
> + return 1;
> +}
--
paul-moore.com
On Apr 28, 2023 kernel test robot <[email protected]> wrote:
>
> Add lsm_name_to_attr(), which translates a text string to a
> LSM_ATTR value if one is available.
>
> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
> the trailing attribute value. The .len value is padded to a multiple
> of 64 bits for alignment.
>
> All are used in module specific components of LSM system calls.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> ---
> include/linux/security.h | 13 ++++++++++++
> security/lsm_syscalls.c | 24 ++++++++++++++++++++++
> security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 81 insertions(+)
...
> diff --git a/security/security.c b/security/security.c
> index 94b78bfd06b9..8c877d639cae 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -761,6 +761,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
> return 0;
> }
>
> +/**
> + * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
> + * @ctx: an LSM context to be filled
> + * @context: the new context value
> + * @context_size: the size of the new context value
> + * @id: LSM id
> + * @flags: LSM defined flags
> + *
> + * Fill all of the fields in a user space lsm_ctx structure.
> + * Caller is assumed to have verified that @ctx has enough space
> + * for @context.
> + *
> + * The total length is padded to a multiple of 64 bits to
> + * accomodate possible alignment issues.
> + *
> + * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
> + * if memory can't be allocated.
> + */
> +int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
> + size_t context_size, u64 id, u64 flags)
> +{
> + struct lsm_ctx *lctx;
> + size_t locallen = ALIGN(struct_size(lctx, ctx, context_size), 8);
See my comment in 7/11 regarding the alignment calculation here.
> + int rc = 0;
> +
> + lctx = kzalloc(locallen, GFP_KERNEL);
> + if (lctx == NULL)
> + return -ENOMEM;
> +
> + lctx->id = id;
> + lctx->flags = flags;
> + lctx->ctx_len = context_size;
> + lctx->len = locallen;
> +
> + memcpy(lctx->ctx, context, context_size);
> +
> + if (copy_to_user(ctx, lctx, locallen))
> + rc = -EFAULT;
> +
> + kfree(lctx);
> +
> + return rc;
> +}
> +
> /*
> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
> * can be accessed with:
> --
> 2.39.2
--
paul-moore.com
On 6/7/2023 3:32 PM, Paul Moore wrote:
> On Apr 28, 2023 Casey Schaufler <[email protected]> wrote:
>> Create a system call lsm_get_self_attr() to provide the security
>> module maintained attributes of the current process.
>> Create a system call lsm_set_self_attr() to set a security
>> module maintained attribute of the current process.
>> Historically these attributes have been exposed to user space via
>> entries in procfs under /proc/self/attr.
>>
>> The attribute value is provided in a lsm_ctx structure. The structure
>> identifies the size of the attribute, and the attribute value. The format
>> of the attribute value is defined by the security module. A flags field
>> is included for LSM specific information. It is currently unused and must
>> be 0. The total size of the data, including the lsm_ctx structure and any
>> padding, is maintained as well.
>>
>> struct lsm_ctx {
>> __u64 id;
>> __u64 flags;
>> __u64 len;
>> __u64 ctx_len;
>> __u8 ctx[];
>> };
>>
>> Two new LSM hooks are used to interface with the LSMs.
>> security_getselfattr() collects the lsm_ctx values from the
>> LSMs that support the hook, accounting for space requirements.
>> security_setselfattr() identifies which LSM the attribute is
>> intended for and passes it along.
>>
>> Signed-off-by: Casey Schaufler <[email protected]>
>> Reviewed-by: Kees Cook <[email protected]>
>> ---
>> Documentation/userspace-api/lsm.rst | 15 ++++
>> include/linux/lsm_hook_defs.h | 4 +
>> include/linux/lsm_hooks.h | 9 +++
>> include/linux/security.h | 19 +++++
>> include/linux/syscalls.h | 5 ++
>> include/uapi/linux/lsm.h | 36 +++++++++
>> kernel/sys_ni.c | 4 +
>> security/Makefile | 1 +
>> security/lsm_syscalls.c | 55 ++++++++++++++
>> security/security.c | 112 ++++++++++++++++++++++++++++
>> 10 files changed, 260 insertions(+)
>> create mode 100644 security/lsm_syscalls.c
> ..
>
>> diff --git a/security/security.c b/security/security.c
>> index 5a48b1b539e5..94b78bfd06b9 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -2176,6 +2176,118 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
>> }
>> EXPORT_SYMBOL(security_d_instantiate);
>>
>> +/**
>> + * security_getselfattr - Read an LSM attribute of the current process.
>> + * @attr: which attribute to return
>> + * @ctx: the user-space destination for the information, or NULL
>> + * @size: the size of space available to receive the data
>> + * @flags: special handling options. LSM_FLAG_SINGLE indicates that only
>> + * attributes associated with the LSM identified in the passed @ctx be
>> + * reported
>> + *
>> + * Returns the number of attributes found on success, negative value
>> + * on error. @size is reset to the total size of the data.
>> + * If @size is insufficient to contain the data -E2BIG is returned.
>> + */
>> +int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
>> + size_t __user *size, u32 flags)
>> +{
>> + struct security_hook_list *hp;
>> + struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, };
>> + u8 __user *base = (u8 __user *)ctx;
>> + size_t total = 0;
>> + size_t entrysize;
>> + size_t left;
>> + bool toobig = false;
>> + int count = 0;
>> + int rc;
>> +
>> + if (attr == 0)
>> + return -EINVAL;
>> + if (size == NULL)
>> + return -EINVAL;
>> + if (get_user(left, size))
>> + return -EFAULT;
>> +
>> + if ((flags & LSM_FLAG_SINGLE) == LSM_FLAG_SINGLE) {
>> + if (!ctx)
>> + return -EINVAL;
>> + if (copy_struct_from_user(&lctx, sizeof(lctx), ctx, left))
>> + return -EFAULT;
>> + if (lctx.id == LSM_ID_UNDEF)
>> + return -EINVAL;
>> + } else if (flags) {
>> + return -EINVAL;
>> + }
>> +
>> + hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) {
>> + if (lctx.id != LSM_ID_UNDEF && lctx.id != hp->lsmid->id)
>> + continue;
> I think we're missing a copy_struct_from_user() call somewhere; how
> does @lctx get populated in the non-LSM_FLAG_SINGLE case? How does
> it move to the next entry in the buffer?
@lctx.id is initialized to LSM_ID_UNDEF in the declaration. In the
non-LSM_FLAG_SINGLE case the lsmctx.id != LSM_ID_UNDEF test will always
fail, thus avoiding the continue. It is only necessary to do the
copy_struct_from_user() call in the LSM_FLAG_SINGLE case.
> Am I missing something obvious?
Yes.
> Was this code tested?
Yes. See patch 11/11.
>
>> + entrysize = left;
>> + if (base)
>> + ctx = (struct lsm_ctx __user *)(base + total);
>> + rc = hp->hook.getselfattr(attr, ctx, &entrysize, flags);
>> + if (rc == -EOPNOTSUPP) {
>> + rc = 0;
>> + continue;
>> + }
>> + if (rc == -E2BIG) {
>> + toobig = true;
>> + left = 0;
>> + continue;
>> + }
>> + if (rc < 0)
>> + return rc;
>> +
>> + left -= entrysize;
>> + total += entrysize;
>> + count += rc;
>> + }
>> + if (put_user(total, size))
>> + return -EFAULT;
>> + if (toobig)
>> + return -E2BIG;
>> + if (count == 0)
>> + return LSM_RET_DEFAULT(getselfattr);
>> + return count;
>> +}
>> +
>> +/**
>> + * security_setselfattr - Set an LSM attribute on the current process.
>> + * @attr: which attribute to set
>> + * @ctx: the user-space source for the information
>> + * @size: the size of the data
>> + * @flags: reserved for future use, must be 0
>> + *
>> + * Set an LSM attribute for the current process. The LSM, attribute
>> + * and new value are included in @ctx.
>> + *
>> + * Returns 0 on success, -EINVAL if the input is inconsistent, -EFAULT
>> + * if the user buffer is inaccessible or an LSM specific failure.
>> + */
>> +int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
>> + size_t size, u32 flags)
>> +{
>> + struct security_hook_list *hp;
>> + struct lsm_ctx lctx;
>> +
>> + if (flags)
>> + return -EINVAL;
> Once again, I don't see a reasonable way to support setting an
> attribute across multiple LSMs, but for the sake of consistency
> across both the getselfattr and setselfattr syscalls, what do
> people think about *requiring* the LSM_FLAG_SINGLE flag here in
> the setselfattr syscalls since it can only operate on a single
> LSM at a time? A zero flag value would return -EINVAL.
Requiring a pointless flag seems like an API no-no to me.
>
>> + if (size < sizeof(*ctx))
>> + return -EINVAL;
>> + if (copy_from_user(&lctx, ctx, sizeof(*ctx)))
>> + return -EFAULT;
>> + if (size < lctx.len || size < lctx.ctx_len + sizeof(ctx) ||
>> + lctx.len < lctx.ctx_len + sizeof(ctx))
>> + return -EINVAL;
>> +
>> + hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list)
>> + if ((hp->lsmid->id) == lctx.id)
>> + return hp->hook.setselfattr(attr, ctx, size, flags);
>> +
>> + return LSM_RET_DEFAULT(setselfattr);
>> +}
>> +
>> int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
>> char **value)
>> {
>> --
>> 2.39.2
> --
> paul-moore.com
On 6/7/2023 3:32 PM, Paul Moore wrote:
> On Apr 28, 2023 Casey Schaufler <[email protected]> wrote:
>> Add hooks for setselfattr and getselfattr. These hooks are not very
>> different from their setprocattr and getprocattr equivalents, and
>> much of the code is shared.
>>
>> Signed-off-by: Casey Schaufler <[email protected]>
>> Cc: [email protected]
>> Cc: Paul Moore <[email protected]>
>> ---
>> security/selinux/hooks.c | 154 +++++++++++++++++++++++++++++++--------
>> 1 file changed, 124 insertions(+), 30 deletions(-)
>>
>> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
>> index 2ee92d3fb79d..e78b955e04f8 100644
>> --- a/security/selinux/hooks.c
>> +++ b/security/selinux/hooks.c
>> @@ -6542,6 +6559,81 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
>> return error;
>> }
>>
>> +static int selinux_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
>> + size_t *size, u32 flags)
>> +{
>> + char *value;
>> + size_t total_len;
>> + int len;
>> + int rc;
>> +
>> + len = selinux_lsm_getattr(attr, current, &value);
>> + if (len < 0)
>> + return len;
>> +
>> + total_len = ALIGN(struct_size(ctx, ctx, len), 8);
>> +
>> + if (total_len > *size)
>> + rc = -E2BIG;
> Hmm. Since we need to calculate the aligned @total_len value in the
> LSM specific code, perhaps it doesn't make sense to also do the
> alignment in lsm_fill_user_ctx(). My apologies, I know I was the one
> who suggested doing the alignment in a common place previously.
Some future user of lsm_fill_user_ctx() may not need to do the
calculation, so I would be inclined to leave it here. I'm thinking
SO_PEERCONTEXT, or the like. But I'll go with whatever gets the
patchset moving forward.
>
>> + else if (ctx)
>> + rc = lsm_fill_user_ctx(ctx, value, len, LSM_ID_SELINUX, 0);
>> + else
>> + rc = 1;
>> +
>> + *size = total_len;
>> + if (rc < 0)
>> + return rc;
>> + return 1;
>> +}
> --
> paul-moore.com
On Fri, Apr 28, 2023 at 01:34:11PM -0700, Casey Schaufler wrote:
> Create a system call to report the list of Linux Security Modules
> that are active on the system. The list is provided as an array
> of LSM ID numbers.
>
> The calling application can use this list determine what LSM
> specific actions it might take. That might include choosing an
> output format, determining required privilege or bypassing
> security module specific behavior.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
One comment below, but
Reviewed-by: Serge E. Hallyn <[email protected]>
> ---
> Documentation/userspace-api/lsm.rst | 3 +++
> include/linux/syscalls.h | 1 +
> kernel/sys_ni.c | 1 +
> security/lsm_syscalls.c | 39 +++++++++++++++++++++++++++++
> 4 files changed, 44 insertions(+)
>
> diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst
> index e6c3f262addc..9edae18a2688 100644
> --- a/Documentation/userspace-api/lsm.rst
> +++ b/Documentation/userspace-api/lsm.rst
> @@ -63,6 +63,9 @@ Get the specified security attributes of the current process
> .. kernel-doc:: security/lsm_syscalls.c
> :identifiers: sys_lsm_get_self_attr
>
> +.. kernel-doc:: security/lsm_syscalls.c
> + :identifiers: sys_lsm_list_modules
> +
> Additional documentation
> ========================
>
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 9a94c31bf6b6..ddbcc333f3c3 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1063,6 +1063,7 @@ asmlinkage long sys_lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> size_t *size, __u32 flags);
> asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> size_t size, __u32 flags);
> +asmlinkage long sys_lsm_list_modules(u64 *ids, size_t *size, u32 flags);
>
> /*
> * Architecture-specific system calls
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index d03c78ef1562..ceb3d21a62d0 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -265,6 +265,7 @@ COND_SYSCALL(mremap);
> /* security/lsm_syscalls.c */
> COND_SYSCALL(lsm_get_self_attr);
> COND_SYSCALL(lsm_set_self_attr);
> +COND_SYSCALL(lsm_list_modules);
>
> /* security/keys/keyctl.c */
> COND_SYSCALL(add_key);
> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
> index ee3881159241..b89cccb2f123 100644
> --- a/security/lsm_syscalls.c
> +++ b/security/lsm_syscalls.c
> @@ -53,3 +53,42 @@ SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
> {
> return security_getselfattr(attr, ctx, size, flags);
> }
> +
> +/**
> + * sys_lsm_list_modules - Return a list of the active security modules
> + * @ids: the LSM module ids
Again, I would say "pointer to size"
> + * @size: size of @ids, updated on return
> + * @flags: reserved for future use, must be zero
> + *
> + * Returns a list of the active LSM ids. On success this function
> + * returns the number of @ids array elements. This value may be zero
> + * if there are no LSMs active. If @size is insufficient to contain
> + * the return data -E2BIG is returned and @size is set to the minimum
> + * required size. In all other cases a negative value indicating the
> + * error is returned.
> + */
> +SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, size_t __user *, size,
> + u32, flags)
> +{
> + size_t total_size = lsm_active_cnt * sizeof(*ids);
> + size_t usize;
> + int i;
> +
> + if (flags)
> + return -EINVAL;
> +
> + if (get_user(usize, size))
> + return -EFAULT;
> +
> + if (put_user(total_size, size) != 0)
> + return -EFAULT;
> +
> + if (usize < total_size)
> + return -E2BIG;
> +
> + for (i = 0; i < lsm_active_cnt; i++)
> + if (put_user(lsm_idlist[i]->id, ids++))
> + return -EFAULT;
> +
> + return lsm_active_cnt;
> +}
> --
> 2.39.2
>
On Fri, Apr 28, 2023 at 01:34:10PM -0700, Casey Schaufler wrote:
> Create a system call lsm_get_self_attr() to provide the security
> module maintained attributes of the current process.
> Create a system call lsm_set_self_attr() to set a security
> module maintained attribute of the current process.
> Historically these attributes have been exposed to user space via
> entries in procfs under /proc/self/attr.
>
> The attribute value is provided in a lsm_ctx structure. The structure
> identifies the size of the attribute, and the attribute value. The format
> of the attribute value is defined by the security module. A flags field
> is included for LSM specific information. It is currently unused and must
> be 0. The total size of the data, including the lsm_ctx structure and any
> padding, is maintained as well.
>
> struct lsm_ctx {
> __u64 id;
> __u64 flags;
> __u64 len;
> __u64 ctx_len;
> __u8 ctx[];
> };
>
> Two new LSM hooks are used to interface with the LSMs.
> security_getselfattr() collects the lsm_ctx values from the
> LSMs that support the hook, accounting for space requirements.
> security_setselfattr() identifies which LSM the attribute is
> intended for and passes it along.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
Just two comments below. With those (or with good counter
arguments)
Reviewed-by: Serge E. Hallyn <[email protected]>
> ---
> Documentation/userspace-api/lsm.rst | 15 ++++
> include/linux/lsm_hook_defs.h | 4 +
> include/linux/lsm_hooks.h | 9 +++
> include/linux/security.h | 19 +++++
> include/linux/syscalls.h | 5 ++
> include/uapi/linux/lsm.h | 36 +++++++++
> kernel/sys_ni.c | 4 +
> security/Makefile | 1 +
> security/lsm_syscalls.c | 55 ++++++++++++++
> security/security.c | 112 ++++++++++++++++++++++++++++
> 10 files changed, 260 insertions(+)
> create mode 100644 security/lsm_syscalls.c
>
> diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst
> index 6ddf5506110b..e6c3f262addc 100644
> --- a/Documentation/userspace-api/lsm.rst
> +++ b/Documentation/userspace-api/lsm.rst
> @@ -48,6 +48,21 @@ creating socket objects.
> The proc filesystem provides this value in ``/proc/self/attr/sockcreate``.
> This is supported by the SELinux security module.
>
> +Kernel interface
> +================
> +
> +Set a security attribute of the current process
> +-----------------------------------------------
> +
> +.. kernel-doc:: security/lsm_syscalls.c
> + :identifiers: sys_lsm_set_self_attr
> +
> +Get the specified security attributes of the current process
> +------------------------------------------------------------
> +
> +.. kernel-doc:: security/lsm_syscalls.c
> + :identifiers: sys_lsm_get_self_attr
> +
> Additional documentation
> ========================
>
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 094b76dc7164..32104ff61999 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -261,6 +261,10 @@ LSM_HOOK(int, 0, sem_semop, struct kern_ipc_perm *perm, struct sembuf *sops,
> LSM_HOOK(int, 0, netlink_send, struct sock *sk, struct sk_buff *skb)
> LSM_HOOK(void, LSM_RET_VOID, d_instantiate, struct dentry *dentry,
> struct inode *inode)
> +LSM_HOOK(int, -EOPNOTSUPP, getselfattr, unsigned int attr,
> + struct lsm_ctx __user *ctx, size_t *size, u32 flags)
> +LSM_HOOK(int, -EOPNOTSUPP, setselfattr, unsigned int attr,
> + struct lsm_ctx __user *ctx, size_t size, u32 flags)
> LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, const char *name,
> char **value)
> LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size)
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index c1f00d09033e..457ff953e331 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -25,6 +25,7 @@
> #ifndef __LINUX_LSM_HOOKS_H
> #define __LINUX_LSM_HOOKS_H
>
> +#include <uapi/linux/lsm.h>
> #include <linux/security.h>
> #include <linux/init.h>
> #include <linux/rculist.h>
> @@ -503,6 +504,14 @@
> * and writing the xattrs as this hook is merely a filter.
> * @d_instantiate:
> * Fill in @inode security information for a @dentry if allowed.
> + * @getselfattr:
> + * Read attribute @attr for the current process and store it into @ctx.
> + * Return 0 on success, -EOPNOTSUPP if the attribute is not supported,
> + * or another negative value otherwise.
> + * @setselfattr:
> + * Set attribute @attr for the current process.
> + * Return 0 on success, -EOPNOTSUPP if the attribute is not supported,
> + * or another negative value otherwise.
> * @getprocattr:
> * Read attribute @name for process @p and store it into @value if allowed.
> * Return the length of @value on success, a negative value otherwise.
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 8faed81fc3b4..806bff425af9 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -60,6 +60,7 @@ struct fs_parameter;
> enum fs_value_type;
> struct watch;
> struct watch_notification;
> +struct lsm_ctx;
>
> /* Default (no) options for the capable function */
> #define CAP_OPT_NONE 0x0
> @@ -473,6 +474,10 @@ int security_sem_semctl(struct kern_ipc_perm *sma, int cmd);
> int security_sem_semop(struct kern_ipc_perm *sma, struct sembuf *sops,
> unsigned nsops, int alter);
> void security_d_instantiate(struct dentry *dentry, struct inode *inode);
> +int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t __user *size, u32 flags);
> +int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t size, u32 flags);
> int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
> char **value);
> int security_setprocattr(int lsmid, const char *name, void *value, size_t size);
> @@ -1343,6 +1348,20 @@ static inline void security_d_instantiate(struct dentry *dentry,
> struct inode *inode)
> { }
>
> +static inline int security_getselfattr(unsigned int attr,
> + struct lsm_ctx __user *ctx,
> + size_t __user *size, u32 flags)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static inline int security_setselfattr(unsigned int attr,
> + struct lsm_ctx __user *ctx,
> + size_t size, u32 flags)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> static inline int security_getprocattr(struct task_struct *p, int lsmid,
> const char *name, char **value)
> {
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 33a0ee3bcb2e..9a94c31bf6b6 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -71,6 +71,7 @@ struct clone_args;
> struct open_how;
> struct mount_attr;
> struct landlock_ruleset_attr;
> +struct lsm_ctx;
> enum landlock_rule_type;
>
> #include <linux/types.h>
> @@ -1058,6 +1059,10 @@ asmlinkage long sys_memfd_secret(unsigned int flags);
> asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long len,
> unsigned long home_node,
> unsigned long flags);
> +asmlinkage long sys_lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> + size_t *size, __u32 flags);
> +asmlinkage long sys_lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx,
> + size_t size, __u32 flags);
>
> /*
> * Architecture-specific system calls
> diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
> index f27c9a9cc376..eeda59a77c02 100644
> --- a/include/uapi/linux/lsm.h
> +++ b/include/uapi/linux/lsm.h
> @@ -9,6 +9,36 @@
> #ifndef _UAPI_LINUX_LSM_H
> #define _UAPI_LINUX_LSM_H
>
> +#include <linux/types.h>
> +#include <linux/unistd.h>
> +
> +/**
> + * struct lsm_ctx - LSM context information
> + * @id: the LSM id number, see LSM_ID_XXX
> + * @flags: LSM specific flags
> + * @len: length of the lsm_ctx struct, @ctx and any other data or padding
> + * @ctx_len: the size of @ctx
> + * @ctx: the LSM context value
> + *
> + * The @len field MUST be equal to the size of the lsm_ctx struct
> + * plus any additional padding and/or data placed after @ctx.
> + *
> + * In all cases @ctx_len MUST be equal to the length of @ctx.
> + * If @ctx is a string value it should be nul terminated with
> + * @ctx_len equal to `strlen(@ctx) + 1`. Binary values are
> + * supported.
> + *
> + * The @flags and @ctx fields SHOULD only be interpreted by the
> + * LSM specified by @id; they MUST be set to zero/0 when not used.
> + */
> +struct lsm_ctx {
> + __u64 id;
> + __u64 flags;
> + __u64 len;
> + __u64 ctx_len;
> + __u8 ctx[];
> +};
> +
> /*
> * ID tokens to identify Linux Security Modules (LSMs)
> *
> @@ -51,4 +81,10 @@
> #define LSM_ATTR_PREV 104
> #define LSM_ATTR_SOCKCREATE 105
>
> +/*
> + * LSM_FLAG_XXX definitions identify special handling instructions
> + * for the API.
> + */
> +#define LSM_FLAG_SINGLE 0x0001
> +
> #endif /* _UAPI_LINUX_LSM_H */
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index 860b2dcf3ac4..d03c78ef1562 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -262,6 +262,10 @@ COND_SYSCALL_COMPAT(recvmsg);
> /* mm/nommu.c, also with MMU */
> COND_SYSCALL(mremap);
>
> +/* security/lsm_syscalls.c */
> +COND_SYSCALL(lsm_get_self_attr);
> +COND_SYSCALL(lsm_set_self_attr);
> +
> /* security/keys/keyctl.c */
> COND_SYSCALL(add_key);
> COND_SYSCALL(request_key);
> diff --git a/security/Makefile b/security/Makefile
> index 18121f8f85cd..59f238490665 100644
> --- a/security/Makefile
> +++ b/security/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_KEYS) += keys/
>
> # always enable default capabilities
> obj-y += commoncap.o
> +obj-$(CONFIG_SECURITY) += lsm_syscalls.o
> obj-$(CONFIG_MMU) += min_addr.o
>
> # Object file lists
> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
> new file mode 100644
> index 000000000000..ee3881159241
> --- /dev/null
> +++ b/security/lsm_syscalls.c
> @@ -0,0 +1,55 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * System calls implementing the Linux Security Module API.
> + *
> + * Copyright (C) 2022 Casey Schaufler <[email protected]>
> + * Copyright (C) 2022 Intel Corporation
> + */
> +
> +#include <asm/current.h>
> +#include <linux/compiler_types.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/security.h>
> +#include <linux/stddef.h>
> +#include <linux/syscalls.h>
> +#include <linux/types.h>
> +#include <linux/lsm_hooks.h>
> +#include <uapi/linux/lsm.h>
> +
> +/**
> + * sys_lsm_set_self_attr - Set current task's security module attribute
> + * @attr: which attribute to set
> + * @ctx: the LSM contexts
> + * @size: size of @ctx
> + * @flags: reserved for future use
> + *
> + * Sets the calling task's LSM context. On success this function
> + * returns 0. If the attribute specified cannot be set a negative
> + * value indicating the reason for the error is returned.
> + */
> +SYSCALL_DEFINE4(lsm_set_self_attr, unsigned int, attr, struct lsm_ctx __user *,
> + ctx, size_t, size, u32, flags)
> +{
> + return security_setselfattr(attr, ctx, size, flags);
> +}
> +
> +/**
> + * sys_lsm_get_self_attr - Return current task's security module attributes
> + * @attr: which attribute to set
> + * @ctx: the LSM contexts
> + * @size: size of @ctx, updated on return
> + * @flags: reserved for future use
> + *
> + * Returns the calling task's LSM contexts. On success this
> + * function returns the number of @ctx array elements. This value
> + * may be zero if there are no LSM contexts assigned. If @size is
> + * insufficient to contain the return data -E2BIG is returned and
> + * @size is set to the minimum required size. In all other cases
> + * a negative value indicating the error is returned.
> + */
> +SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
> + ctx, size_t __user *, size, u32, flags)
> +{
> + return security_getselfattr(attr, ctx, size, flags);
> +}
> diff --git a/security/security.c b/security/security.c
> index 5a48b1b539e5..94b78bfd06b9 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2176,6 +2176,118 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
> }
> EXPORT_SYMBOL(security_d_instantiate);
>
> +/**
> + * security_getselfattr - Read an LSM attribute of the current process.
> + * @attr: which attribute to return
> + * @ctx: the user-space destination for the information, or NULL
It may seem too obvious to bother, but it seems to me this should
say "pointer to the size of space..." to be as precise as possible.
> + * @size: the size of space available to receive the data
> + * @flags: special handling options. LSM_FLAG_SINGLE indicates that only
> + * attributes associated with the LSM identified in the passed @ctx be
> + * reported
> + *
> + * Returns the number of attributes found on success, negative value
> + * on error. @size is reset to the total size of the data.
> + * If @size is insufficient to contain the data -E2BIG is returned.
> + */
> +int security_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t __user *size, u32 flags)
> +{
> + struct security_hook_list *hp;
> + struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, };
> + u8 __user *base = (u8 __user *)ctx;
> + size_t total = 0;
> + size_t entrysize;
> + size_t left;
> + bool toobig = false;
> + int count = 0;
> + int rc;
> +
> + if (attr == 0)
Should this be if (attr == LSM_ATTR_UNDEF) ?
> + return -EINVAL;
> + if (size == NULL)
> + return -EINVAL;
> + if (get_user(left, size))
> + return -EFAULT;
> +
> + if ((flags & LSM_FLAG_SINGLE) == LSM_FLAG_SINGLE) {
> + if (!ctx)
> + return -EINVAL;
> + if (copy_struct_from_user(&lctx, sizeof(lctx), ctx, left))
> + return -EFAULT;
> + if (lctx.id == LSM_ID_UNDEF)
> + return -EINVAL;
> + } else if (flags) {
> + return -EINVAL;
> + }
> +
> + hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) {
> + if (lctx.id != LSM_ID_UNDEF && lctx.id != hp->lsmid->id)
> + continue;
> + entrysize = left;
> + if (base)
> + ctx = (struct lsm_ctx __user *)(base + total);
> + rc = hp->hook.getselfattr(attr, ctx, &entrysize, flags);
> + if (rc == -EOPNOTSUPP) {
> + rc = 0;
> + continue;
> + }
> + if (rc == -E2BIG) {
> + toobig = true;
> + left = 0;
> + continue;
> + }
> + if (rc < 0)
> + return rc;
> +
> + left -= entrysize;
> + total += entrysize;
> + count += rc;
> + }
> + if (put_user(total, size))
> + return -EFAULT;
> + if (toobig)
> + return -E2BIG;
> + if (count == 0)
> + return LSM_RET_DEFAULT(getselfattr);
> + return count;
> +}
> +
> +/**
> + * security_setselfattr - Set an LSM attribute on the current process.
> + * @attr: which attribute to set
> + * @ctx: the user-space source for the information
> + * @size: the size of the data
> + * @flags: reserved for future use, must be 0
> + *
> + * Set an LSM attribute for the current process. The LSM, attribute
> + * and new value are included in @ctx.
> + *
> + * Returns 0 on success, -EINVAL if the input is inconsistent, -EFAULT
> + * if the user buffer is inaccessible or an LSM specific failure.
> + */
> +int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t size, u32 flags)
> +{
> + struct security_hook_list *hp;
> + struct lsm_ctx lctx;
> +
> + if (flags)
> + return -EINVAL;
> + if (size < sizeof(*ctx))
> + return -EINVAL;
> + if (copy_from_user(&lctx, ctx, sizeof(*ctx)))
> + return -EFAULT;
> + if (size < lctx.len || size < lctx.ctx_len + sizeof(ctx) ||
> + lctx.len < lctx.ctx_len + sizeof(ctx))
> + return -EINVAL;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list)
> + if ((hp->lsmid->id) == lctx.id)
> + return hp->hook.setselfattr(attr, ctx, size, flags);
> +
> + return LSM_RET_DEFAULT(setselfattr);
> +}
> +
> int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
> char **value)
> {
> --
> 2.39.2
>
On Fri, Apr 28, 2023 at 01:34:13PM -0700, Casey Schaufler wrote:
> Add lsm_name_to_attr(), which translates a text string to a
> LSM_ATTR value if one is available.
>
> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
> the trailing attribute value. The .len value is padded to a multiple
> of 64 bits for alignment.
>
> All are used in module specific components of LSM system calls.
>
> Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Serge E. Hallyn <[email protected]>
> ---
> include/linux/security.h | 13 ++++++++++++
> security/lsm_syscalls.c | 24 ++++++++++++++++++++++
> security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 81 insertions(+)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 806bff425af9..36ace59f9171 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -263,6 +263,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb);
> /* prototypes */
> extern int security_init(void);
> extern int early_security_init(void);
> +extern u64 lsm_name_to_attr(const char *name);
>
> /* Security operations */
> int security_binder_set_context_mgr(const struct cred *mgr);
> @@ -491,6 +492,8 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
> int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
> int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
> int security_locked_down(enum lockdown_reason what);
> +int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
> + size_t context_size, u64 id, u64 flags);
> #else /* CONFIG_SECURITY */
>
> static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
> @@ -508,6 +511,11 @@ static inline int unregister_blocking_lsm_notifier(struct notifier_block *nb)
> return 0;
> }
>
> +static inline u64 lsm_name_to_attr(const char *name)
> +{
> + return LSM_ATTR_UNDEF;
> +}
> +
> static inline void security_free_mnt_opts(void **mnt_opts)
> {
> }
> @@ -1420,6 +1428,11 @@ static inline int security_locked_down(enum lockdown_reason what)
> {
> return 0;
> }
> +static inline int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
> + size_t context_size, u64 id, u64 flags)
> +{
> + return -EOPNOTSUPP;
> +}
> #endif /* CONFIG_SECURITY */
>
> #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
> index b89cccb2f123..0b225adfe5f7 100644
> --- a/security/lsm_syscalls.c
> +++ b/security/lsm_syscalls.c
> @@ -17,6 +17,30 @@
> #include <linux/lsm_hooks.h>
> #include <uapi/linux/lsm.h>
>
> +/**
> + * lsm_name_to_attr - map an LSM attribute name to its ID
> + * @name: name of the attribute
> + *
> + * Returns the LSM attribute value associated with @name, or 0 if
> + * there is no mapping.
> + */
> +u64 lsm_name_to_attr(const char *name)
> +{
> + if (!strcmp(name, "current"))
> + return LSM_ATTR_CURRENT;
> + if (!strcmp(name, "exec"))
> + return LSM_ATTR_EXEC;
> + if (!strcmp(name, "fscreate"))
> + return LSM_ATTR_FSCREATE;
> + if (!strcmp(name, "keycreate"))
> + return LSM_ATTR_KEYCREATE;
> + if (!strcmp(name, "prev"))
> + return LSM_ATTR_PREV;
> + if (!strcmp(name, "sockcreate"))
> + return LSM_ATTR_SOCKCREATE;
> + return LSM_ATTR_UNDEF;
> +}
> +
> /**
> * sys_lsm_set_self_attr - Set current task's security module attribute
> * @attr: which attribute to set
> diff --git a/security/security.c b/security/security.c
> index 94b78bfd06b9..8c877d639cae 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -761,6 +761,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
> return 0;
> }
>
> +/**
> + * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
> + * @ctx: an LSM context to be filled
> + * @context: the new context value
> + * @context_size: the size of the new context value
> + * @id: LSM id
> + * @flags: LSM defined flags
> + *
> + * Fill all of the fields in a user space lsm_ctx structure.
> + * Caller is assumed to have verified that @ctx has enough space
> + * for @context.
> + *
> + * The total length is padded to a multiple of 64 bits to
> + * accomodate possible alignment issues.
> + *
> + * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
> + * if memory can't be allocated.
> + */
> +int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
> + size_t context_size, u64 id, u64 flags)
> +{
> + struct lsm_ctx *lctx;
> + size_t locallen = ALIGN(struct_size(lctx, ctx, context_size), 8);
> + int rc = 0;
> +
> + lctx = kzalloc(locallen, GFP_KERNEL);
> + if (lctx == NULL)
> + return -ENOMEM;
> +
> + lctx->id = id;
> + lctx->flags = flags;
> + lctx->ctx_len = context_size;
> + lctx->len = locallen;
> +
> + memcpy(lctx->ctx, context, context_size);
> +
> + if (copy_to_user(ctx, lctx, locallen))
> + rc = -EFAULT;
> +
> + kfree(lctx);
> +
> + return rc;
> +}
> +
> /*
> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
> * can be accessed with:
> --
> 2.39.2
>
On Fri, Apr 28, 2023 at 01:34:13PM -0700, Casey Schaufler wrote:
> Add lsm_name_to_attr(), which translates a text string to a
> LSM_ATTR value if one is available.
>
> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
> the trailing attribute value. The .len value is padded to a multiple
> of 64 bits for alignment.
>
> All are used in module specific components of LSM system calls.
>
> Signed-off-by: Casey Schaufler <[email protected]>
(I assume you have a patch queued up for the undefined errors?)