From: Roberto Sassu <[email protected]>
IMA and EVM are not effectively LSMs, especially due to the fact that in
the past they could not provide a security blob while there is another LSM
active.
That changed in the recent years, the LSM stacking feature now makes it
possible to stack together multiple LSMs, and allows them to provide a
security blob for most kernel objects. While the LSM stacking feature has
some limitations being worked out, it is already suitable to make IMA and
EVM as LSMs.
The main purpose of this patch set is to remove IMA and EVM function calls,
hardcoded in the LSM infrastructure and other places in the kernel, and to
register them as LSM hook implementations, so that those functions are
called by the LSM infrastructure like other regular LSMs.
This patch set introduces two new LSMs 'ima' and 'evm', so that functions
can be registered to their respective LSM, and removes the 'integrity' LSM.
integrity_kernel_module_request() was moved to IMA, since deadlock could
occur only there. integrity_inode_free() was replaced with ima_inode_free()
(EVM does not need to free memory).
In order to make 'ima' and 'evm' independent LSMs, it was necessary to
split integrity metadata used by both IMA and EVM, and to let them manage
their own. The special case of the IMA_NEW_FILE flag, managed by IMA and
used by EVM, was handled by introducing a new flag in EVM, EVM_NEW_FILE,
managed by two additional LSM hooks, evm_post_path_mknod() and
evm_file_release(), equivalent to their counterparts ima_post_path_mknod()
and ima_file_free().
In addition to splitting metadata, it was decided to embed the
evm_iint_inode structure into the inode security blob, since it is small
and because anyway it cannot rely on IMA anymore allocating it (since it
uses a different structure).
On the other hand, to avoid memory pressure concerns, only a pointer to the
ima_iint_cache structure is stored in the inode security blob, and the
structure is allocated on demand, like before.
Another follow-up change was removing the iint parameter from
evm_verifyxattr(), that IMA used to pass integrity metadata to EVM. After
splitting metadata, and aligning EVM_NEW_FILE with IMA_NEW_FILE, this
parameter was not necessary anymore.
The last part was to ensure that the order of IMA and EVM functions is
respected after they become LSMs. Since the order of lsm_info structures in
the .lsm_info.init section depends on the order object files containing
those structures are passed to the linker of the kernel image, and since
IMA is before EVM in the Makefile, that is sufficient to assert that IMA
functions are executed before EVM ones.
The patch set is organized as follows.
Patches 1-9 make IMA and EVM functions suitable to be registered to the LSM
infrastructure, by aligning function parameters.
Patches 10-18 add new LSM hooks in the same places where IMA and EVM
functions are called, if there is no LSM hook already.
Patch 19 moves integrity_kernel_module_request() to IMA, as a prerequisite
for removing the 'integrity' LSM.
Patches 20-22 introduce the new standalone LSMs 'ima' and 'evm', and move
hardcoded calls to IMA, EVM and integrity functions to those LSMs.
Patches 23-24 remove the dependency on the 'integrity' LSM by splitting
integrity metadata, so that the 'ima' and 'evm' LSMs can use their own.
They also duplicate iint_lockdep_annotate() in ima_main.c, since the mutex
field was moved from integrity_iint_cache to ima_iint_cache.
Patch 25 finally removes the 'integrity' LSM, since 'ima' and 'evm' are now
self-contained and independent.
The patch set applies on top of lsm/next, commit 97280fa1ed94 ("Automated
merge of 'dev' into 'next'").
Changelog:
v9:
- Add new Reviewed-by/Acked-by
- Rewrite documentation of ima_kernel_module_request() (suggested by
Stefan)
- Move evm_inode_post_setxattr() registration after evm_inode_setxattr()
(suggested by Stefan)
v8:
- Restore dynamic allocation of IMA integrity metadata, and store only the
pointer in the inode security blob
- Select SECURITY_PATH both in IMA and EVM
- Rename evm_file_free() to evm_file_release()
- Unconditionally register evm_post_path_mknod()
- Introduce the new ima_iint.c file for the management of IMA integrity
metadata
- Introduce ima_inode_set_iint()/ima_inode_get_iint() in ima.h to
respectively store/retrieve the IMA integrity metadata pointer
- Replace ima_iint_inode() with ima_inode_get() and ima_iint_find(), with
same behavior of integrity_inode_get() and integrity_iint_find()
- Initialize the ima_iint_cache in ima_iintcache_init() and call it from
init_ima_lsm()
- Move integrity_kernel_module_request() to IMA in a separate patch
(suggested by Mimi)
- Compile ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS
is enabled
- Remove ima_inode_alloc_security() and ima_inode_free_security(), since
the IMA integrity metadata is not fully embedded in the inode security
blob
- Fixed the missed initialization of ima_iint_cache in
process_measurement() and __ima_inode_hash()
- Add a sentence in 'evm: Move to LSM infrastructure' to mention about
moving evm_inode_remove_acl(), evm_inode_post_remove_acl() and
evm_inode_post_set_acl() to evm_main.c
- Add a sentence in 'ima: Move IMA-Appraisal to LSM infrastructure' to
mention about moving ima_inode_remove_acl() to ima_appraise.c
v7:
- Use return instead of goto in __vfs_removexattr_locked() (suggested by
Casey)
- Clarify in security/integrity/Makefile that the order of 'ima' and 'evm'
LSMs depends on the order in which IMA and EVM are compiled
- Move integrity_iint_cache flags to ima.h and evm.h in security/ and
duplicate IMA_NEW_FILE to EVM_NEW_FILE
- Rename evm_inode_get_iint() to evm_iint_inode() and ima_inode_get_iint()
to ima_iint_inode(), check if inode->i_security is NULL, and just return
the pointer from the inode security blob
- Restore the non-NULL checks after ima_iint_inode() and evm_iint_inode()
(suggested by Casey)
- Introduce evm_file_free() to clear EVM_NEW_FILE
- Remove comment about LSM_ORDER_LAST not guaranteeing the order of 'ima'
and 'evm' LSMs
- Lock iint->mutex before reading IMA_COLLECTED flag in __ima_inode_hash()
and restored ima_policy_flag check
- Remove patch about the hardcoded ordering of 'ima' and 'evm' LSMs in
security.c
- Add missing ima_inode_free_security() to free iint->ima_hash
- Add the cases for LSM_ID_IMA and LSM_ID_EVM in lsm_list_modules_test.c
- Mention about the change in IMA and EVM post functions for private
inodes
v6:
- See v7
v5:
- Rename security_file_pre_free() to security_file_release() and the LSM
hook file_pre_free_security to file_release (suggested by Paul)
- Move integrity_kernel_module_request() to ima_main.c (renamed to
ima_kernel_module_request())
- Split the integrity_iint_cache structure into ima_iint_cache and
evm_iint_cache, so that IMA and EVM can use disjoint metadata and
reserve space with the LSM infrastructure
- Reserve space for the entire ima_iint_cache and evm_iint_cache
structures, not just the pointer (suggested by Paul)
- Introduce ima_inode_get_iint() and evm_inode_get_iint() to retrieve
respectively the ima_iint_cache and evm_iint_cache structure from the
security blob
- Remove the various non-NULL checks for the ima_iint_cache and
evm_iint_cache structures, since the LSM infrastructure ensure that they
always exist
- Remove the iint parameter from evm_verifyxattr() since IMA and EVM
use disjoint integrity metaddata
- Introduce the evm_post_path_mknod() to set the IMA_NEW_FILE flag
- Register the inode_alloc_security LSM hook in IMA and EVM to
initialize the respective integrity metadata structures
- Remove the 'integrity' LSM completely and instead make 'ima' and 'evm'
proper standalone LSMs
- Add the inode parameter to ima_get_verity_digest(), since the inode
field is not present in ima_iint_cache
- Move iint_lockdep_annotate() to ima_main.c (renamed to
ima_iint_lockdep_annotate())
- Remove ima_get_lsm_id() and evm_get_lsm_id(), since IMA and EVM directly
register the needed LSM hooks
- Enforce 'ima' and 'evm' LSM ordering at LSM infrastructure level
v4:
- Improve short and long description of
security_inode_post_create_tmpfile(), security_inode_post_set_acl(),
security_inode_post_remove_acl() and security_file_post_open()
(suggested by Mimi)
- Improve commit message of 'ima: Move to LSM infrastructure' (suggested
by Mimi)
v3:
- Drop 'ima: Align ima_post_path_mknod() definition with LSM
infrastructure' and 'ima: Align ima_post_create_tmpfile() definition
with LSM infrastructure', define the new LSM hooks with the same
IMA parameters instead (suggested by Mimi)
- Do IS_PRIVATE() check in security_path_post_mknod() and
security_inode_post_create_tmpfile() on the new inode rather than the
parent directory (in the post method it is available)
- Don't export ima_file_check() (suggested by Stefan)
- Remove redundant check of file mode in ima_post_path_mknod() (suggested
by Mimi)
- Mention that ima_post_path_mknod() is now conditionally invoked when
CONFIG_SECURITY_PATH=y (suggested by Mimi)
- Mention when a LSM hook will be introduced in the IMA/EVM alignment
patches (suggested by Mimi)
- Simplify the commit messages when introducing a new LSM hook
- Still keep the 'extern' in the function declaration, until the
declaration is removed (suggested by Mimi)
- Improve documentation of security_file_pre_free()
- Register 'ima' and 'evm' as standalone LSMs (suggested by Paul)
- Initialize the 'ima' and 'evm' LSMs from 'integrity', to keep the
original ordering of IMA and EVM functions as when they were hardcoded
- Return the IMA and EVM LSM IDs to 'integrity' for registration of the
integrity-specific hooks
- Reserve an xattr slot from the 'evm' LSM instead of 'integrity'
- Pass the LSM ID to init_ima_appraise_lsm()
v2:
- Add description for newly introduced LSM hooks (suggested by Casey)
- Clarify in the description of security_file_pre_free() that actions can
be performed while the file is still open
v1:
- Drop 'evm: Complete description of evm_inode_setattr()', 'fs: Fix
description of vfs_tmpfile()' and 'security: Introduce LSM_ORDER_LAST',
they were sent separately (suggested by Christian Brauner)
- Replace dentry with file descriptor parameter for
security_inode_post_create_tmpfile()
- Introduce mode_stripped and pass it as mode argument to
security_path_mknod() and security_path_post_mknod()
- Use goto in do_mknodat() and __vfs_removexattr_locked() (suggested by
Mimi)
- Replace __lsm_ro_after_init with __ro_after_init
- Modify short description of security_inode_post_create_tmpfile() and
security_inode_post_set_acl() (suggested by Stefan)
- Move security_inode_post_setattr() just after security_inode_setattr()
(suggested by Mimi)
- Modify short description of security_key_post_create_or_update()
(suggested by Mimi)
- Add back exported functions ima_file_check() and
evm_inode_init_security() respectively to ima.h and evm.h (reported by
kernel robot)
- Remove extern from prototype declarations and fix style issues
- Remove unnecessary include of linux/lsm_hooks.h in ima_main.c and
ima_appraise.c
Roberto Sassu (25):
ima: Align ima_inode_post_setattr() definition with LSM infrastructure
ima: Align ima_file_mprotect() definition with LSM infrastructure
ima: Align ima_inode_setxattr() definition with LSM infrastructure
ima: Align ima_inode_removexattr() definition with LSM infrastructure
ima: Align ima_post_read_file() definition with LSM infrastructure
evm: Align evm_inode_post_setattr() definition with LSM infrastructure
evm: Align evm_inode_setxattr() definition with LSM infrastructure
evm: Align evm_inode_post_setxattr() definition with LSM
infrastructure
security: Align inode_setattr hook definition with EVM
security: Introduce inode_post_setattr hook
security: Introduce inode_post_removexattr hook
security: Introduce file_post_open hook
security: Introduce file_release hook
security: Introduce path_post_mknod hook
security: Introduce inode_post_create_tmpfile hook
security: Introduce inode_post_set_acl hook
security: Introduce inode_post_remove_acl hook
security: Introduce key_post_create_or_update hook
integrity: Move integrity_kernel_module_request() to IMA
ima: Move to LSM infrastructure
ima: Move IMA-Appraisal to LSM infrastructure
evm: Move to LSM infrastructure
evm: Make it independent from 'integrity' LSM
ima: Make it independent from 'integrity' LSM
integrity: Remove LSM
fs/attr.c | 5 +-
fs/file_table.c | 3 +-
fs/namei.c | 12 +-
fs/nfsd/vfs.c | 3 +-
fs/open.c | 1 -
fs/posix_acl.c | 5 +-
fs/xattr.c | 9 +-
include/linux/evm.h | 117 +-------
include/linux/ima.h | 142 ----------
include/linux/integrity.h | 27 --
include/linux/lsm_hook_defs.h | 20 +-
include/linux/security.h | 59 ++++
include/uapi/linux/lsm.h | 2 +
security/integrity/Makefile | 1 +
security/integrity/digsig_asymmetric.c | 23 --
security/integrity/evm/Kconfig | 1 +
security/integrity/evm/evm.h | 19 ++
security/integrity/evm/evm_crypto.c | 4 +-
security/integrity/evm/evm_main.c | 195 ++++++++++---
security/integrity/iint.c | 197 +------------
security/integrity/ima/Kconfig | 1 +
security/integrity/ima/Makefile | 2 +-
security/integrity/ima/ima.h | 148 ++++++++--
security/integrity/ima/ima_api.c | 23 +-
security/integrity/ima/ima_appraise.c | 66 +++--
security/integrity/ima/ima_iint.c | 142 ++++++++++
security/integrity/ima/ima_init.c | 2 +-
security/integrity/ima/ima_main.c | 148 +++++++---
security/integrity/ima/ima_policy.c | 2 +-
security/integrity/integrity.h | 80 +-----
security/keys/key.c | 10 +-
security/security.c | 263 +++++++++++-------
security/selinux/hooks.c | 3 +-
security/smack/smack_lsm.c | 4 +-
.../selftests/lsm/lsm_list_modules_test.c | 6 +
35 files changed, 906 insertions(+), 839 deletions(-)
create mode 100644 security/integrity/ima/ima_iint.c
--
2.34.1
From: Roberto Sassu <[email protected]>
Change ima_inode_post_setattr() definition, so that it can be registered as
implementation of the inode_post_setattr hook (to be introduced).
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Paul Moore <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
fs/attr.c | 2 +-
include/linux/ima.h | 4 ++--
security/integrity/ima/ima_appraise.c | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index 5a13f0c8495f..b53ae408ad4f 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -502,7 +502,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_change(dentry, ia_valid);
- ima_inode_post_setattr(idmap, dentry);
+ ima_inode_post_setattr(idmap, dentry, ia_valid);
evm_inode_post_setattr(dentry, ia_valid);
}
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 86b57757c7b1..910a2f11a906 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -186,7 +186,7 @@ static inline void ima_post_key_create_or_update(struct key *keyring,
#ifdef CONFIG_IMA_APPRAISE
extern bool is_ima_appraise_enabled(void);
extern void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry);
+ struct dentry *dentry, int ia_valid);
extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
const void *xattr_value, size_t xattr_value_len);
extern int ima_inode_set_acl(struct mnt_idmap *idmap,
@@ -206,7 +206,7 @@ static inline bool is_ima_appraise_enabled(void)
}
static inline void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry)
+ struct dentry *dentry, int ia_valid)
{
return;
}
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 870dde67707b..36c2938a5c69 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -629,6 +629,7 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
* ima_inode_post_setattr - reflect file metadata changes
* @idmap: idmap of the mount the inode was found from
* @dentry: pointer to the affected dentry
+ * @ia_valid: for the UID and GID status
*
* Changes to a dentry's metadata might result in needing to appraise.
*
@@ -636,7 +637,7 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
* to lock the inode's i_mutex.
*/
void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry)
+ struct dentry *dentry, int ia_valid)
{
struct inode *inode = d_backing_inode(dentry);
struct integrity_iint_cache *iint;
--
2.34.1
From: Roberto Sassu <[email protected]>
Change evm_inode_post_setattr() definition, so that it can be registered as
implementation of the inode_post_setattr hook (to be introduced).
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Paul Moore <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
fs/attr.c | 2 +-
include/linux/evm.h | 6 ++++--
security/integrity/evm/evm_main.c | 4 +++-
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index b53ae408ad4f..adeba0ec40f1 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -503,7 +503,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_change(dentry, ia_valid);
ima_inode_post_setattr(idmap, dentry, ia_valid);
- evm_inode_post_setattr(dentry, ia_valid);
+ evm_inode_post_setattr(idmap, dentry, ia_valid);
}
return error;
diff --git a/include/linux/evm.h b/include/linux/evm.h
index 36ec884320d9..5cc386312b5a 100644
--- a/include/linux/evm.h
+++ b/include/linux/evm.h
@@ -23,7 +23,8 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry,
struct integrity_iint_cache *iint);
extern int evm_inode_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr);
-extern void evm_inode_post_setattr(struct dentry *dentry, int ia_valid);
+extern void evm_inode_post_setattr(struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid);
extern int evm_inode_setxattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
const void *value, size_t size);
@@ -98,7 +99,8 @@ static inline int evm_inode_setattr(struct mnt_idmap *idmap,
return 0;
}
-static inline void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
+static inline void evm_inode_post_setattr(struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
{
return;
}
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index cc7956d7878b..ac34f21122cd 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -870,6 +870,7 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
/**
* evm_inode_post_setattr - update 'security.evm' after modifying metadata
+ * @idmap: idmap of the idmapped mount
* @dentry: pointer to the affected dentry
* @ia_valid: for the UID and GID status
*
@@ -879,7 +880,8 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
* This function is called from notify_change(), which expects the caller
* to lock the inode's i_mutex.
*/
-void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
+void evm_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid)
{
if (!evm_revalidate_status(NULL))
return;
--
2.34.1
From: Roberto Sassu <[email protected]>
Change evm_inode_setxattr() definition, so that it can be registered as
implementation of the inode_setxattr hook.
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
include/linux/evm.h | 4 ++--
security/integrity/evm/evm_main.c | 3 ++-
security/security.c | 2 +-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/evm.h b/include/linux/evm.h
index 5cc386312b5a..7de24c1ada90 100644
--- a/include/linux/evm.h
+++ b/include/linux/evm.h
@@ -27,7 +27,7 @@ extern void evm_inode_post_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, int ia_valid);
extern int evm_inode_setxattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
- const void *value, size_t size);
+ const void *value, size_t size, int flags);
extern void evm_inode_post_setxattr(struct dentry *dentry,
const char *xattr_name,
const void *xattr_value,
@@ -107,7 +107,7 @@ static inline void evm_inode_post_setattr(struct mnt_idmap *idmap,
static inline int evm_inode_setxattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
- const void *value, size_t size)
+ const void *value, size_t size, int flags)
{
return 0;
}
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index ac34f21122cd..12ba3207fd31 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -581,6 +581,7 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
* @xattr_name: pointer to the affected extended attribute name
* @xattr_value: pointer to the new extended attribute value
* @xattr_value_len: pointer to the new extended attribute value length
+ * @flags: flags to pass into filesystem operations
*
* Before allowing the 'security.evm' protected xattr to be updated,
* verify the existing value is valid. As only the kernel should have
@@ -590,7 +591,7 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
*/
int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
const char *xattr_name, const void *xattr_value,
- size_t xattr_value_len)
+ size_t xattr_value_len, int flags)
{
const struct evm_ima_xattr_data *xattr_data = xattr_value;
diff --git a/security/security.c b/security/security.c
index feb39de74385..16361f75c2ae 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2273,7 +2273,7 @@ int security_inode_setxattr(struct mnt_idmap *idmap,
ret = ima_inode_setxattr(idmap, dentry, name, value, size, flags);
if (ret)
return ret;
- return evm_inode_setxattr(idmap, dentry, name, value, size);
+ return evm_inode_setxattr(idmap, dentry, name, value, size, flags);
}
/**
--
2.34.1
From: Roberto Sassu <[email protected]>
In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_setattr hook.
At inode_setattr hook, EVM verifies the file's existing HMAC value. At
inode_post_setattr, EVM re-calculates the file's HMAC based on the modified
file attributes and other file metadata.
Other LSMs could similarly take some action after successful file attribute
change.
The new hook cannot return an error and cannot cause the operation to be
reverted.
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
Acked-by: Christian Brauner <[email protected]>
---
fs/attr.c | 1 +
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 7 +++++++
security/security.c | 16 ++++++++++++++++
4 files changed, 26 insertions(+)
diff --git a/fs/attr.c b/fs/attr.c
index adeba0ec40f1..990e1b3a3c91 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -502,6 +502,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_change(dentry, ia_valid);
+ security_inode_post_setattr(idmap, dentry, ia_valid);
ima_inode_post_setattr(idmap, dentry, ia_valid);
evm_inode_post_setattr(idmap, dentry, ia_valid);
}
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index b00b16d58413..a0e9e48015a4 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -137,6 +137,8 @@ LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode,
LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask)
LSM_HOOK(int, 0, inode_setattr, struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
+LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
LSM_HOOK(int, 0, inode_getattr, const struct path *path)
LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap,
struct dentry *dentry, const char *name, const void *value,
diff --git a/include/linux/security.h b/include/linux/security.h
index d0eb20f90b26..56c841aa3994 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -361,6 +361,8 @@ int security_inode_follow_link(struct dentry *dentry, struct inode *inode,
int security_inode_permission(struct inode *inode, int mask);
int security_inode_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr);
+void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid);
int security_inode_getattr(const struct path *path);
int security_inode_setxattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
@@ -879,6 +881,11 @@ static inline int security_inode_setattr(struct mnt_idmap *idmap,
return 0;
}
+static inline void
+security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid)
+{ }
+
static inline int security_inode_getattr(const struct path *path)
{
return 0;
diff --git a/security/security.c b/security/security.c
index 671472b34bbf..8b8a03291a8e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2223,6 +2223,22 @@ int security_inode_setattr(struct mnt_idmap *idmap,
}
EXPORT_SYMBOL_GPL(security_inode_setattr);
+/**
+ * security_inode_post_setattr() - Update the inode after a setattr operation
+ * @idmap: idmap of the mount
+ * @dentry: file
+ * @ia_valid: file attributes set
+ *
+ * Update inode security field after successful setting file attributes.
+ */
+void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid)
+{
+ if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+ return;
+ call_void_hook(inode_post_setattr, idmap, dentry, ia_valid);
+}
+
/**
* security_inode_getattr() - Check if getting file attributes is allowed
* @path: file
--
2.34.1
From: Roberto Sassu <[email protected]>
Change ima_inode_removexattr() definition, so that it can be registered as
implementation of the inode_removexattr hook.
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Paul Moore <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
include/linux/ima.h | 7 +++++--
security/integrity/ima/ima_appraise.c | 3 ++-
security/security.c | 2 +-
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 077324309c11..678a03fddd7e 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -200,7 +200,9 @@ static inline int ima_inode_remove_acl(struct mnt_idmap *idmap,
{
return ima_inode_set_acl(idmap, dentry, acl_name, NULL);
}
-extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
+
+extern int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name);
#else
static inline bool is_ima_appraise_enabled(void)
{
@@ -231,7 +233,8 @@ static inline int ima_inode_set_acl(struct mnt_idmap *idmap,
return 0;
}
-static inline int ima_inode_removexattr(struct dentry *dentry,
+static inline int ima_inode_removexattr(struct mnt_idmap *idmap,
+ struct dentry *dentry,
const char *xattr_name)
{
return 0;
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index cb2d0d11aa77..36abc84ba299 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -790,7 +790,8 @@ int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
return 0;
}
-int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
+int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name)
{
int result;
diff --git a/security/security.c b/security/security.c
index ec572380d0cd..feb39de74385 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2431,7 +2431,7 @@ int security_inode_removexattr(struct mnt_idmap *idmap,
ret = cap_inode_removexattr(idmap, dentry, name);
if (ret)
return ret;
- ret = ima_inode_removexattr(dentry, name);
+ ret = ima_inode_removexattr(idmap, dentry, name);
if (ret)
return ret;
return evm_inode_removexattr(idmap, dentry, name);
--
2.34.1
From: Roberto Sassu <[email protected]>
In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the path_post_mknod hook.
IMA-appraisal requires all existing files in policy to have a file
hash/signature stored in security.ima. An exception is made for empty files
created by mknod, by tagging them as new files.
LSMs could also take some action after files are created.
The new hook cannot return an error and cannot cause the operation to be
reverted.
Signed-off-by: Roberto Sassu <[email protected]>
Acked-by: Casey Schaufler <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Paul Moore <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
---
fs/namei.c | 5 +++++
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 5 +++++
security/security.c | 14 ++++++++++++++
4 files changed, 26 insertions(+)
diff --git a/fs/namei.c b/fs/namei.c
index ef867f1d6704..9280aa5d60a7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4063,6 +4063,11 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
dentry, mode, 0);
break;
}
+
+ if (error)
+ goto out2;
+
+ security_path_post_mknod(idmap, dentry);
out2:
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 7f9e9240606e..dba5d8204dc5 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -94,6 +94,8 @@ LSM_HOOK(int, 0, path_mkdir, const struct path *dir, struct dentry *dentry,
LSM_HOOK(int, 0, path_rmdir, const struct path *dir, struct dentry *dentry)
LSM_HOOK(int, 0, path_mknod, const struct path *dir, struct dentry *dentry,
umode_t mode, unsigned int dev)
+LSM_HOOK(void, LSM_RET_VOID, path_post_mknod, struct mnt_idmap *idmap,
+ struct dentry *dentry)
LSM_HOOK(int, 0, path_truncate, const struct path *path)
LSM_HOOK(int, 0, path_symlink, const struct path *dir, struct dentry *dentry,
const char *old_name)
diff --git a/include/linux/security.h b/include/linux/security.h
index 2997348afcb7..977dd9f7f51a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1893,6 +1893,7 @@ int security_path_mkdir(const struct path *dir, struct dentry *dentry, umode_t m
int security_path_rmdir(const struct path *dir, struct dentry *dentry);
int security_path_mknod(const struct path *dir, struct dentry *dentry, umode_t mode,
unsigned int dev);
+void security_path_post_mknod(struct mnt_idmap *idmap, struct dentry *dentry);
int security_path_truncate(const struct path *path);
int security_path_symlink(const struct path *dir, struct dentry *dentry,
const char *old_name);
@@ -1927,6 +1928,10 @@ static inline int security_path_mknod(const struct path *dir, struct dentry *den
return 0;
}
+static inline void security_path_post_mknod(struct mnt_idmap *idmap,
+ struct dentry *dentry)
+{ }
+
static inline int security_path_truncate(const struct path *path)
{
return 0;
diff --git a/security/security.c b/security/security.c
index 145e3141339c..b55f9ad294cc 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1801,6 +1801,20 @@ int security_path_mknod(const struct path *dir, struct dentry *dentry,
}
EXPORT_SYMBOL(security_path_mknod);
+/**
+ * security_path_post_mknod() - Update inode security field after file creation
+ * @idmap: idmap of the mount
+ * @dentry: new file
+ *
+ * Update inode security field after a file has been created.
+ */
+void security_path_post_mknod(struct mnt_idmap *idmap, struct dentry *dentry)
+{
+ if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+ return;
+ call_void_hook(path_post_mknod, idmap, dentry);
+}
+
/**
* security_path_mkdir() - Check if creating a new directory is allowed
* @dir: parent directory
--
2.34.1
From: Roberto Sassu <[email protected]>
In preparation for removing the 'integrity' LSM, move
integrity_kernel_module_request() to IMA, and rename it to
ima_kernel_module_request(). Rewrite the function documentation, to explain
better what the problem is.
Compile it conditionally if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled,
and call it from security.c (removed afterwards with the move of IMA to the
LSM infrastructure).
Adding this hook cannot be avoided, since IMA has no control on the flags
passed to crypto_alloc_sig() in public_key_verify_signature(), and thus
cannot pass CRYPTO_NOLOAD, which solved the problem for EVM hashing with
commit e2861fa71641 ("evm: Don't deadlock if a crypto algorithm is
unavailable").
EVM alone does not need to implement this hook, first because there is no
mutex to deadlock, and second because even if it had it, there should be a
recursive call. However, since verification from EVM can be initiated only
by setting inode metadata, deadlock would occur if modprobe would do the
same while loading a kernel module (which is unlikely).
Signed-off-by: Roberto Sassu <[email protected]>
Acked-by: Paul Moore <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
include/linux/ima.h | 10 ++++++++
include/linux/integrity.h | 13 ----------
security/integrity/digsig_asymmetric.c | 23 ------------------
security/integrity/ima/ima_main.c | 33 ++++++++++++++++++++++++++
security/security.c | 2 +-
5 files changed, 44 insertions(+), 37 deletions(-)
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 31ef6c3c3207..0f9af283cbc8 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -256,4 +256,14 @@ static inline bool ima_appraise_signature(enum kernel_read_file_id func)
return false;
}
#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
+
+#if defined(CONFIG_IMA) && defined(CONFIG_INTEGRITY_ASYMMETRIC_KEYS)
+extern int ima_kernel_module_request(char *kmod_name);
+#else
+static inline int ima_kernel_module_request(char *kmod_name)
+{
+ return 0;
+}
+
+#endif
#endif /* _LINUX_IMA_H */
diff --git a/include/linux/integrity.h b/include/linux/integrity.h
index 2ea0f2f65ab6..ef0f63ef5ebc 100644
--- a/include/linux/integrity.h
+++ b/include/linux/integrity.h
@@ -42,17 +42,4 @@ static inline void integrity_load_keys(void)
}
#endif /* CONFIG_INTEGRITY */
-#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
-
-extern int integrity_kernel_module_request(char *kmod_name);
-
-#else
-
-static inline int integrity_kernel_module_request(char *kmod_name)
-{
- return 0;
-}
-
-#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
-
#endif /* _LINUX_INTEGRITY_H */
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index 895f4b9ce8c6..de603cf42ac7 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -132,26 +132,3 @@ int asymmetric_verify(struct key *keyring, const char *sig,
pr_debug("%s() = %d\n", __func__, ret);
return ret;
}
-
-/**
- * integrity_kernel_module_request - prevent crypto-pkcs1pad(rsa,*) requests
- * @kmod_name: kernel module name
- *
- * We have situation, when public_key_verify_signature() in case of RSA
- * algorithm use alg_name to store internal information in order to
- * construct an algorithm on the fly, but crypto_larval_lookup() will try
- * to use alg_name in order to load kernel module with same name.
- * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules,
- * we are safe to fail such module request from crypto_larval_lookup().
- *
- * In this way we prevent modprobe execution during digsig verification
- * and avoid possible deadlock if modprobe and/or it's dependencies
- * also signed with digsig.
- */
-int integrity_kernel_module_request(char *kmod_name)
-{
- if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0)
- return -EINVAL;
-
- return 0;
-}
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 02021ee467d3..3891b83efdb3 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1091,6 +1091,39 @@ int ima_measure_critical_data(const char *event_label,
}
EXPORT_SYMBOL_GPL(ima_measure_critical_data);
+#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
+
+/**
+ * ima_kernel_module_request - Prevent crypto-pkcs1pad(rsa,*) requests
+ * @kmod_name: kernel module name
+ *
+ * Avoid a verification loop where verifying the signature of the modprobe
+ * binary requires executing modprobe itself. Since the modprobe iint->mutex
+ * is already held when the signature verification is performed, a deadlock
+ * occurs as soon as modprobe is executed within the critical region, since
+ * the same lock cannot be taken again.
+ *
+ * This happens when public_key_verify_signature(), in case of RSA algorithm,
+ * use alg_name to store internal information in order to construct an
+ * algorithm on the fly, but crypto_larval_lookup() will try to use alg_name
+ * in order to load a kernel module with same name.
+ *
+ * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules,
+ * we are safe to fail such module request from crypto_larval_lookup(), and
+ * avoid the verification loop.
+ *
+ * Return: Zero if it is safe to load the kernel module, -EINVAL otherwise.
+ */
+int ima_kernel_module_request(char *kmod_name)
+{
+ if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
+
static int __init init_ima(void)
{
int error;
diff --git a/security/security.c b/security/security.c
index f8d9ebeb4c31..48dc3db4c834 100644
--- a/security/security.c
+++ b/security/security.c
@@ -3250,7 +3250,7 @@ int security_kernel_module_request(char *kmod_name)
ret = call_int_hook(kernel_module_request, 0, kmod_name);
if (ret)
return ret;
- return integrity_kernel_module_request(kmod_name);
+ return ima_kernel_module_request(kmod_name);
}
/**
--
2.34.1
From: Roberto Sassu <[email protected]>
As for IMA, move hardcoded EVM function calls from various places in the
kernel to the LSM infrastructure, by introducing a new LSM named 'evm'
(last and always enabled like 'ima'). The order in the Makefile ensures
that 'evm' hooks are executed after 'ima' ones.
Make EVM functions as static (except for evm_inode_init_security(), which
is exported), and register them as hook implementations in init_evm_lsm().
Also move the inline functions evm_inode_remove_acl(),
evm_inode_post_remove_acl(), and evm_inode_post_set_acl() from the public
evm.h header to evm_main.c.
Unlike before (see commit to move IMA to the LSM infrastructure),
evm_inode_post_setattr(), evm_inode_post_set_acl(),
evm_inode_post_remove_acl(), and evm_inode_post_removexattr() are not
executed for private inodes.
Finally, add the LSM_ID_EVM case in lsm_list_modules_test.c
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
fs/attr.c | 2 -
fs/posix_acl.c | 3 -
fs/xattr.c | 2 -
include/linux/evm.h | 113 -----------------
include/uapi/linux/lsm.h | 1 +
security/integrity/evm/evm_main.c | 118 +++++++++++++++---
security/security.c | 43 ++-----
.../selftests/lsm/lsm_list_modules_test.c | 3 +
8 files changed, 116 insertions(+), 169 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index 7e97313e7f70..4d0d75953107 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -16,7 +16,6 @@
#include <linux/fcntl.h>
#include <linux/filelock.h>
#include <linux/security.h>
-#include <linux/evm.h>
#include "internal.h"
@@ -502,7 +501,6 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_change(dentry, ia_valid);
security_inode_post_setattr(idmap, dentry, ia_valid);
- evm_inode_post_setattr(idmap, dentry, ia_valid);
}
return error;
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 0d2371240c1b..5c90239e3f2b 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -26,7 +26,6 @@
#include <linux/mnt_idmapping.h>
#include <linux/iversion.h>
#include <linux/security.h>
-#include <linux/evm.h>
#include <linux/fsnotify.h>
#include <linux/filelock.h>
@@ -1138,7 +1137,6 @@ int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_xattr(dentry);
security_inode_post_set_acl(dentry, acl_name, kacl);
- evm_inode_post_set_acl(dentry, acl_name, kacl);
}
out_inode_unlock:
@@ -1247,7 +1245,6 @@ int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
if (!error) {
fsnotify_xattr(dentry);
security_inode_post_remove_acl(idmap, dentry, acl_name);
- evm_inode_post_remove_acl(idmap, dentry, acl_name);
}
out_inode_unlock:
diff --git a/fs/xattr.c b/fs/xattr.c
index f891c260a971..f8b643f91a98 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -16,7 +16,6 @@
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.h>
-#include <linux/evm.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fsnotify.h>
@@ -557,7 +556,6 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
fsnotify_xattr(dentry);
security_inode_post_removexattr(dentry, name);
- evm_inode_post_removexattr(dentry, name);
out:
return error;
diff --git a/include/linux/evm.h b/include/linux/evm.h
index 3faabdd47852..cb481eccc967 100644
--- a/include/linux/evm.h
+++ b/include/linux/evm.h
@@ -21,45 +21,6 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry,
void *xattr_value,
size_t xattr_value_len,
struct integrity_iint_cache *iint);
-extern int evm_inode_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, struct iattr *attr);
-extern void evm_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, int ia_valid);
-extern int evm_inode_setxattr(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags);
-extern void evm_inode_post_setxattr(struct dentry *dentry,
- const char *xattr_name,
- const void *xattr_value,
- size_t xattr_value_len,
- int flags);
-extern int evm_inode_copy_up_xattr(const char *name);
-extern int evm_inode_removexattr(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *xattr_name);
-extern void evm_inode_post_removexattr(struct dentry *dentry,
- const char *xattr_name);
-static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- evm_inode_post_removexattr(dentry, acl_name);
-}
-extern int evm_inode_set_acl(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *acl_name,
- struct posix_acl *kacl);
-static inline int evm_inode_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- return evm_inode_set_acl(idmap, dentry, acl_name, NULL);
-}
-static inline void evm_inode_post_set_acl(struct dentry *dentry,
- const char *acl_name,
- struct posix_acl *kacl)
-{
- return evm_inode_post_setxattr(dentry, acl_name, NULL, 0, 0);
-}
-
int evm_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr, struct xattr *xattrs,
int *xattr_count);
@@ -94,80 +55,6 @@ static inline enum integrity_status evm_verifyxattr(struct dentry *dentry,
}
#endif
-static inline int evm_inode_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, struct iattr *attr)
-{
- return 0;
-}
-
-static inline void evm_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, int ia_valid)
-{
- return;
-}
-
-static inline int evm_inode_setxattr(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
-{
- return 0;
-}
-
-static inline void evm_inode_post_setxattr(struct dentry *dentry,
- const char *xattr_name,
- const void *xattr_value,
- size_t xattr_value_len,
- int flags)
-{
- return;
-}
-
-static inline int evm_inode_copy_up_xattr(const char *name)
-{
- return 0;
-}
-
-static inline int evm_inode_removexattr(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *xattr_name)
-{
- return 0;
-}
-
-static inline void evm_inode_post_removexattr(struct dentry *dentry,
- const char *xattr_name)
-{
- return;
-}
-
-static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- return;
-}
-
-static inline int evm_inode_set_acl(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *acl_name,
- struct posix_acl *kacl)
-{
- return 0;
-}
-
-static inline int evm_inode_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- return 0;
-}
-
-static inline void evm_inode_post_set_acl(struct dentry *dentry,
- const char *acl_name,
- struct posix_acl *kacl)
-{
- return;
-}
-
static inline int evm_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr,
struct xattr *xattrs,
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
index b3b7fd699b63..33d8c9f4aa6b 100644
--- a/include/uapi/linux/lsm.h
+++ b/include/uapi/linux/lsm.h
@@ -63,6 +63,7 @@ struct lsm_ctx {
#define LSM_ID_BPF 109
#define LSM_ID_LANDLOCK 110
#define LSM_ID_IMA 111
+#define LSM_ID_EVM 112
/*
* LSM_ATTR_XXX definitions identify different LSM attributes
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index d35143179699..0a089af83a45 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -589,9 +589,9 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
* userspace from writing HMAC value. Writing 'security.evm' requires
* requires CAP_SYS_ADMIN privileges.
*/
-int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *xattr_name, const void *xattr_value,
- size_t xattr_value_len, int flags)
+static int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name, const void *xattr_value,
+ size_t xattr_value_len, int flags)
{
const struct evm_ima_xattr_data *xattr_data = xattr_value;
@@ -621,8 +621,8 @@ int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
* Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that
* the current value is valid.
*/
-int evm_inode_removexattr(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *xattr_name)
+static int evm_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name)
{
/* Policy permits modification of the protected xattrs even though
* there's no HMAC key loaded
@@ -672,9 +672,11 @@ static inline int evm_inode_set_acl_change(struct mnt_idmap *idmap,
* Prevent modifying posix acls causing the EVM HMAC to be re-calculated
* and 'security.evm' xattr updated, unless the existing 'security.evm' is
* valid.
+ *
+ * Return: zero on success, -EPERM on failure.
*/
-int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *acl_name, struct posix_acl *kacl)
+static int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name, struct posix_acl *kacl)
{
enum integrity_status evm_status;
@@ -713,6 +715,24 @@ int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
return -EPERM;
}
+/**
+ * evm_inode_remove_acl - Protect the EVM extended attribute from posix acls
+ * @idmap: idmap of the mount
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ *
+ * Prevent removing posix acls causing the EVM HMAC to be re-calculated
+ * and 'security.evm' xattr updated, unless the existing 'security.evm' is
+ * valid.
+ *
+ * Return: zero on success, -EPERM on failure.
+ */
+static int evm_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name)
+{
+ return evm_inode_set_acl(idmap, dentry, acl_name, NULL);
+}
+
static void evm_reset_status(struct inode *inode)
{
struct integrity_iint_cache *iint;
@@ -761,9 +781,11 @@ bool evm_revalidate_status(const char *xattr_name)
* __vfs_setxattr_noperm(). The caller of which has taken the inode's
* i_mutex lock.
*/
-void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
- const void *xattr_value, size_t xattr_value_len,
- int flags)
+static void evm_inode_post_setxattr(struct dentry *dentry,
+ const char *xattr_name,
+ const void *xattr_value,
+ size_t xattr_value_len,
+ int flags)
{
if (!evm_revalidate_status(xattr_name))
return;
@@ -782,6 +804,21 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
}
+/**
+ * evm_inode_post_set_acl - Update the EVM extended attribute from posix acls
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ * @kacl: pointer to the posix acls
+ *
+ * Update the 'security.evm' xattr with the EVM HMAC re-calculated after setting
+ * posix acls.
+ */
+static void evm_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
+ struct posix_acl *kacl)
+{
+ return evm_inode_post_setxattr(dentry, acl_name, NULL, 0, 0);
+}
+
/**
* evm_inode_post_removexattr - update 'security.evm' after removing the xattr
* @dentry: pointer to the affected dentry
@@ -792,7 +829,8 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
* No need to take the i_mutex lock here, as this function is called from
* vfs_removexattr() which takes the i_mutex.
*/
-void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
+static void evm_inode_post_removexattr(struct dentry *dentry,
+ const char *xattr_name)
{
if (!evm_revalidate_status(xattr_name))
return;
@@ -808,6 +846,22 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
evm_update_evmxattr(dentry, xattr_name, NULL, 0);
}
+/**
+ * evm_inode_post_remove_acl - Update the EVM extended attribute from posix acls
+ * @idmap: idmap of the mount
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ *
+ * Update the 'security.evm' xattr with the EVM HMAC re-calculated after
+ * removing posix acls.
+ */
+static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap,
+ struct dentry *dentry,
+ const char *acl_name)
+{
+ evm_inode_post_removexattr(dentry, acl_name);
+}
+
static int evm_attr_change(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr)
{
@@ -831,8 +885,8 @@ static int evm_attr_change(struct mnt_idmap *idmap,
* Permit update of file attributes when files have a valid EVM signature,
* except in the case of them having an immutable portable signature.
*/
-int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *attr)
+static int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
enum integrity_status evm_status;
@@ -883,8 +937,8 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
* This function is called from notify_change(), which expects the caller
* to lock the inode's i_mutex.
*/
-void evm_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
- int ia_valid)
+static void evm_inode_post_setattr(struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
{
if (!evm_revalidate_status(NULL))
return;
@@ -901,7 +955,7 @@ void evm_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
evm_update_evmxattr(dentry, NULL, NULL, 0);
}
-int evm_inode_copy_up_xattr(const char *name)
+static int evm_inode_copy_up_xattr(const char *name)
{
if (strcmp(name, XATTR_NAME_EVM) == 0)
return 1; /* Discard */
@@ -1004,4 +1058,36 @@ static int __init init_evm(void)
return error;
}
+static struct security_hook_list evm_hooks[] __ro_after_init = {
+ LSM_HOOK_INIT(inode_setattr, evm_inode_setattr),
+ LSM_HOOK_INIT(inode_post_setattr, evm_inode_post_setattr),
+ LSM_HOOK_INIT(inode_copy_up_xattr, evm_inode_copy_up_xattr),
+ LSM_HOOK_INIT(inode_setxattr, evm_inode_setxattr),
+ LSM_HOOK_INIT(inode_post_setxattr, evm_inode_post_setxattr),
+ LSM_HOOK_INIT(inode_set_acl, evm_inode_set_acl),
+ LSM_HOOK_INIT(inode_post_set_acl, evm_inode_post_set_acl),
+ LSM_HOOK_INIT(inode_remove_acl, evm_inode_remove_acl),
+ LSM_HOOK_INIT(inode_post_remove_acl, evm_inode_post_remove_acl),
+ LSM_HOOK_INIT(inode_removexattr, evm_inode_removexattr),
+ LSM_HOOK_INIT(inode_post_removexattr, evm_inode_post_removexattr),
+ LSM_HOOK_INIT(inode_init_security, evm_inode_init_security),
+};
+
+static const struct lsm_id evm_lsmid = {
+ .name = "evm",
+ .id = LSM_ID_EVM,
+};
+
+static int __init init_evm_lsm(void)
+{
+ security_add_hooks(evm_hooks, ARRAY_SIZE(evm_hooks), &evm_lsmid);
+ return 0;
+}
+
+DEFINE_LSM(evm) = {
+ .name = "evm",
+ .init = init_evm_lsm,
+ .order = LSM_ORDER_LAST,
+};
+
late_initcall(init_evm);
diff --git a/security/security.c b/security/security.c
index 0030af4afa9d..6b439242d117 100644
--- a/security/security.c
+++ b/security/security.c
@@ -20,13 +20,13 @@
#include <linux/kernel_read_file.h>
#include <linux/lsm_hooks.h>
#include <linux/integrity.h>
-#include <linux/evm.h>
#include <linux/fsnotify.h>
#include <linux/mman.h>
#include <linux/mount.h>
#include <linux/personality.h>
#include <linux/backing-dev.h>
#include <linux/string.h>
+#include <linux/xattr.h>
#include <linux/msg.h>
#include <linux/overflow.h>
#include <net/flow.h>
@@ -51,7 +51,8 @@
(IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \
(IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_IMA) ? 1 : 0))
+ (IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \
+ (IS_ENABLED(CONFIG_EVM) ? 1 : 0))
/*
* These are descriptions of the reasons that can be passed to the
@@ -1741,10 +1742,6 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
if (!xattr_count)
goto out;
- ret = evm_inode_init_security(inode, dir, qstr, new_xattrs,
- &xattr_count);
- if (ret)
- goto out;
ret = initxattrs(inode, new_xattrs, fs_data);
out:
for (; xattr_count > 0; xattr_count--)
@@ -2236,14 +2233,9 @@ int security_inode_permission(struct inode *inode, int mask)
int security_inode_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr)
{
- int ret;
-
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
return 0;
- ret = call_int_hook(inode_setattr, 0, idmap, dentry, attr);
- if (ret)
- return ret;
- return evm_inode_setattr(idmap, dentry, attr);
+ return call_int_hook(inode_setattr, 0, idmap, dentry, attr);
}
EXPORT_SYMBOL_GPL(security_inode_setattr);
@@ -2308,9 +2300,7 @@ int security_inode_setxattr(struct mnt_idmap *idmap,
if (ret == 1)
ret = cap_inode_setxattr(dentry, name, value, size, flags);
- if (ret)
- return ret;
- return evm_inode_setxattr(idmap, dentry, name, value, size, flags);
+ return ret;
}
/**
@@ -2329,15 +2319,10 @@ int security_inode_set_acl(struct mnt_idmap *idmap,
struct dentry *dentry, const char *acl_name,
struct posix_acl *kacl)
{
- int ret;
-
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
return 0;
- ret = call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name,
- kacl);
- if (ret)
- return ret;
- return evm_inode_set_acl(idmap, dentry, acl_name, kacl);
+ return call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name,
+ kacl);
}
/**
@@ -2390,14 +2375,9 @@ int security_inode_get_acl(struct mnt_idmap *idmap,
int security_inode_remove_acl(struct mnt_idmap *idmap,
struct dentry *dentry, const char *acl_name)
{
- int ret;
-
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
return 0;
- ret = call_int_hook(inode_remove_acl, 0, idmap, dentry, acl_name);
- if (ret)
- return ret;
- return evm_inode_remove_acl(idmap, dentry, acl_name);
+ return call_int_hook(inode_remove_acl, 0, idmap, dentry, acl_name);
}
/**
@@ -2433,7 +2413,6 @@ void security_inode_post_setxattr(struct dentry *dentry, const char *name,
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
return;
call_void_hook(inode_post_setxattr, dentry, name, value, size, flags);
- evm_inode_post_setxattr(dentry, name, value, size, flags);
}
/**
@@ -2494,9 +2473,7 @@ int security_inode_removexattr(struct mnt_idmap *idmap,
ret = call_int_hook(inode_removexattr, 1, idmap, dentry, name);
if (ret == 1)
ret = cap_inode_removexattr(idmap, dentry, name);
- if (ret)
- return ret;
- return evm_inode_removexattr(idmap, dentry, name);
+ return ret;
}
/**
@@ -2700,7 +2677,7 @@ int security_inode_copy_up_xattr(const char *name)
return rc;
}
- return evm_inode_copy_up_xattr(name);
+ return LSM_RET_DEFAULT(inode_copy_up_xattr);
}
EXPORT_SYMBOL(security_inode_copy_up_xattr);
diff --git a/tools/testing/selftests/lsm/lsm_list_modules_test.c b/tools/testing/selftests/lsm/lsm_list_modules_test.c
index 17333787cb2f..4d5d4cee2586 100644
--- a/tools/testing/selftests/lsm/lsm_list_modules_test.c
+++ b/tools/testing/selftests/lsm/lsm_list_modules_test.c
@@ -125,6 +125,9 @@ TEST(correct_lsm_list_modules)
case LSM_ID_IMA:
name = "ima";
break;
+ case LSM_ID_EVM:
+ name = "evm";
+ break;
default:
name = "INVALID";
break;
--
2.34.1
From: Roberto Sassu <[email protected]>
Since now IMA and EVM use their own integrity metadata, it is safe to
remove the 'integrity' LSM, with its management of integrity metadata.
Keep the iint.c file only for loading IMA and EVM keys at boot, and for
creating the integrity directory in securityfs (we need to keep it for
retrocompatibility reasons).
Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
include/linux/integrity.h | 14 ---
security/integrity/iint.c | 197 +--------------------------------
security/integrity/integrity.h | 25 -----
security/security.c | 2 -
4 files changed, 2 insertions(+), 236 deletions(-)
diff --git a/include/linux/integrity.h b/include/linux/integrity.h
index ef0f63ef5ebc..459b79683783 100644
--- a/include/linux/integrity.h
+++ b/include/linux/integrity.h
@@ -19,24 +19,10 @@ enum integrity_status {
INTEGRITY_UNKNOWN,
};
-/* List of EVM protected security xattrs */
#ifdef CONFIG_INTEGRITY
-extern struct integrity_iint_cache *integrity_inode_get(struct inode *inode);
-extern void integrity_inode_free(struct inode *inode);
extern void __init integrity_load_keys(void);
#else
-static inline struct integrity_iint_cache *
- integrity_inode_get(struct inode *inode)
-{
- return NULL;
-}
-
-static inline void integrity_inode_free(struct inode *inode)
-{
- return;
-}
-
static inline void integrity_load_keys(void)
{
}
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index d4419a2a1e24..068ac6c2ae1e 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -6,207 +6,14 @@
* Mimi Zohar <[email protected]>
*
* File: integrity_iint.c
- * - implements the integrity hooks: integrity_inode_alloc,
- * integrity_inode_free
- * - cache integrity information associated with an inode
- * using a rbtree tree.
+ * - initialize the integrity directory in securityfs
+ * - load IMA and EVM keys
*/
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
-#include <linux/rbtree.h>
-#include <linux/file.h>
-#include <linux/uaccess.h>
#include <linux/security.h>
-#include <linux/lsm_hooks.h>
#include "integrity.h"
-static struct rb_root integrity_iint_tree = RB_ROOT;
-static DEFINE_RWLOCK(integrity_iint_lock);
-static struct kmem_cache *iint_cache __ro_after_init;
-
struct dentry *integrity_dir;
-/*
- * __integrity_iint_find - return the iint associated with an inode
- */
-static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
-{
- struct integrity_iint_cache *iint;
- struct rb_node *n = integrity_iint_tree.rb_node;
-
- while (n) {
- iint = rb_entry(n, struct integrity_iint_cache, rb_node);
-
- if (inode < iint->inode)
- n = n->rb_left;
- else if (inode > iint->inode)
- n = n->rb_right;
- else
- return iint;
- }
-
- return NULL;
-}
-
-/*
- * integrity_iint_find - return the iint associated with an inode
- */
-struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
-{
- struct integrity_iint_cache *iint;
-
- if (!IS_IMA(inode))
- return NULL;
-
- read_lock(&integrity_iint_lock);
- iint = __integrity_iint_find(inode);
- read_unlock(&integrity_iint_lock);
-
- return iint;
-}
-
-#define IMA_MAX_NESTING (FILESYSTEM_MAX_STACK_DEPTH+1)
-
-/*
- * It is not clear that IMA should be nested at all, but as long is it measures
- * files both on overlayfs and on underlying fs, we need to annotate the iint
- * mutex to avoid lockdep false positives related to IMA + overlayfs.
- * See ovl_lockdep_annotate_inode_mutex_key() for more details.
- */
-static inline void iint_lockdep_annotate(struct integrity_iint_cache *iint,
- struct inode *inode)
-{
-#ifdef CONFIG_LOCKDEP
- static struct lock_class_key iint_mutex_key[IMA_MAX_NESTING];
-
- int depth = inode->i_sb->s_stack_depth;
-
- if (WARN_ON_ONCE(depth < 0 || depth >= IMA_MAX_NESTING))
- depth = 0;
-
- lockdep_set_class(&iint->mutex, &iint_mutex_key[depth]);
-#endif
-}
-
-static void iint_init_always(struct integrity_iint_cache *iint,
- struct inode *inode)
-{
- iint->ima_hash = NULL;
- iint->version = 0;
- iint->flags = 0UL;
- iint->atomic_flags = 0UL;
- iint->ima_file_status = INTEGRITY_UNKNOWN;
- iint->ima_mmap_status = INTEGRITY_UNKNOWN;
- iint->ima_bprm_status = INTEGRITY_UNKNOWN;
- iint->ima_read_status = INTEGRITY_UNKNOWN;
- iint->ima_creds_status = INTEGRITY_UNKNOWN;
- iint->evm_status = INTEGRITY_UNKNOWN;
- iint->measured_pcrs = 0;
- mutex_init(&iint->mutex);
- iint_lockdep_annotate(iint, inode);
-}
-
-static void iint_free(struct integrity_iint_cache *iint)
-{
- kfree(iint->ima_hash);
- mutex_destroy(&iint->mutex);
- kmem_cache_free(iint_cache, iint);
-}
-
-/**
- * integrity_inode_get - find or allocate an iint associated with an inode
- * @inode: pointer to the inode
- * @return: allocated iint
- *
- * Caller must lock i_mutex
- */
-struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
-{
- struct rb_node **p;
- struct rb_node *node, *parent = NULL;
- struct integrity_iint_cache *iint, *test_iint;
-
- iint = integrity_iint_find(inode);
- if (iint)
- return iint;
-
- iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
- if (!iint)
- return NULL;
-
- iint_init_always(iint, inode);
-
- write_lock(&integrity_iint_lock);
-
- p = &integrity_iint_tree.rb_node;
- while (*p) {
- parent = *p;
- test_iint = rb_entry(parent, struct integrity_iint_cache,
- rb_node);
- if (inode < test_iint->inode) {
- p = &(*p)->rb_left;
- } else if (inode > test_iint->inode) {
- p = &(*p)->rb_right;
- } else {
- write_unlock(&integrity_iint_lock);
- kmem_cache_free(iint_cache, iint);
- return test_iint;
- }
- }
-
- iint->inode = inode;
- node = &iint->rb_node;
- inode->i_flags |= S_IMA;
- rb_link_node(node, parent, p);
- rb_insert_color(node, &integrity_iint_tree);
-
- write_unlock(&integrity_iint_lock);
- return iint;
-}
-
-/**
- * integrity_inode_free - called on security_inode_free
- * @inode: pointer to the inode
- *
- * Free the integrity information(iint) associated with an inode.
- */
-void integrity_inode_free(struct inode *inode)
-{
- struct integrity_iint_cache *iint;
-
- if (!IS_IMA(inode))
- return;
-
- write_lock(&integrity_iint_lock);
- iint = __integrity_iint_find(inode);
- rb_erase(&iint->rb_node, &integrity_iint_tree);
- write_unlock(&integrity_iint_lock);
-
- iint_free(iint);
-}
-
-static void iint_init_once(void *foo)
-{
- struct integrity_iint_cache *iint = (struct integrity_iint_cache *) foo;
-
- memset(iint, 0, sizeof(*iint));
-}
-
-static int __init integrity_iintcache_init(void)
-{
- iint_cache =
- kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
- 0, SLAB_PANIC, iint_init_once);
- return 0;
-}
-DEFINE_LSM(integrity) = {
- .name = "integrity",
- .init = integrity_iintcache_init,
- .order = LSM_ORDER_LAST,
-};
-
-
/*
* integrity_kernel_read - read data from the file
*
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 671fc50255f9..50d6f798e613 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -102,31 +102,6 @@ struct ima_file_id {
__u8 hash[HASH_MAX_DIGESTSIZE];
} __packed;
-/* integrity data associated with an inode */
-struct integrity_iint_cache {
- struct rb_node rb_node; /* rooted in integrity_iint_tree */
- struct mutex mutex; /* protects: version, flags, digest */
- struct inode *inode; /* back pointer to inode in question */
- u64 version; /* track inode changes */
- unsigned long flags;
- unsigned long measured_pcrs;
- unsigned long atomic_flags;
- unsigned long real_ino;
- dev_t real_dev;
- enum integrity_status ima_file_status:4;
- enum integrity_status ima_mmap_status:4;
- enum integrity_status ima_bprm_status:4;
- enum integrity_status ima_read_status:4;
- enum integrity_status ima_creds_status:4;
- enum integrity_status evm_status:4;
- struct ima_digest_data *ima_hash;
-};
-
-/* rbtree tree calls to lookup, insert, delete
- * integrity data associated with an inode.
- */
-struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
-
int integrity_kernel_read(struct file *file, loff_t offset,
void *addr, unsigned long count);
diff --git a/security/security.c b/security/security.c
index de8a9a7b2a30..4317bcd6ec6a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -19,7 +19,6 @@
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/lsm_hooks.h>
-#include <linux/integrity.h>
#include <linux/fsnotify.h>
#include <linux/mman.h>
#include <linux/mount.h>
@@ -1598,7 +1597,6 @@ static void inode_free_by_rcu(struct rcu_head *head)
*/
void security_inode_free(struct inode *inode)
{
- integrity_inode_free(inode);
call_void_hook(inode_free_security, inode);
/*
* The inode may still be referenced in a path walk and
--
2.34.1
On Thu, 2024-02-15 at 11:31 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <[email protected]>
>
> In preparation for removing the 'integrity' LSM, move
> integrity_kernel_module_request() to IMA, and rename it to
> ima_kernel_module_request(). Rewrite the function documentation, to explain
> better what the problem is.
>
> Compile it conditionally if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled,
> and call it from security.c (removed afterwards with the move of IMA to the
> LSM infrastructure).
>
> Adding this hook cannot be avoided, since IMA has no control on the flags
> passed to crypto_alloc_sig() in public_key_verify_signature(), and thus
> cannot pass CRYPTO_NOLOAD, which solved the problem for EVM hashing with
> commit e2861fa71641 ("evm: Don't deadlock if a crypto algorithm is
> unavailable").
>
> EVM alone does not need to implement this hook, first because there is no
> mutex to deadlock, and second because even if it had it, there should be a
> recursive call. However, since verification from EVM can be initiated only
> by setting inode metadata, deadlock would occur if modprobe would do the
> same while loading a kernel module (which is unlikely).
>
> Signed-off-by: Roberto Sassu <[email protected]>
> Acked-by: Paul Moore <[email protected]>
> Reviewed-by: Stefan Berger <[email protected]>
> Reviewed-by: Mimi Zohar <[email protected]>
> Acked-by: Mimi Zohar <[email protected]>
I hope the change of the ima_kernel_module_request() documentation is
fine for everyone.
If not, let me know.
Thanks
Roberto
> ---
> include/linux/ima.h | 10 ++++++++
> include/linux/integrity.h | 13 ----------
> security/integrity/digsig_asymmetric.c | 23 ------------------
> security/integrity/ima/ima_main.c | 33 ++++++++++++++++++++++++++
> security/security.c | 2 +-
> 5 files changed, 44 insertions(+), 37 deletions(-)
>
> diff --git a/include/linux/ima.h b/include/linux/ima.h
> index 31ef6c3c3207..0f9af283cbc8 100644
> --- a/include/linux/ima.h
> +++ b/include/linux/ima.h
> @@ -256,4 +256,14 @@ static inline bool ima_appraise_signature(enum kernel_read_file_id func)
> return false;
> }
> #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
> +
> +#if defined(CONFIG_IMA) && defined(CONFIG_INTEGRITY_ASYMMETRIC_KEYS)
> +extern int ima_kernel_module_request(char *kmod_name);
> +#else
> +static inline int ima_kernel_module_request(char *kmod_name)
> +{
> + return 0;
> +}
> +
> +#endif
> #endif /* _LINUX_IMA_H */
> diff --git a/include/linux/integrity.h b/include/linux/integrity.h
> index 2ea0f2f65ab6..ef0f63ef5ebc 100644
> --- a/include/linux/integrity.h
> +++ b/include/linux/integrity.h
> @@ -42,17 +42,4 @@ static inline void integrity_load_keys(void)
> }
> #endif /* CONFIG_INTEGRITY */
>
> -#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
> -
> -extern int integrity_kernel_module_request(char *kmod_name);
> -
> -#else
> -
> -static inline int integrity_kernel_module_request(char *kmod_name)
> -{
> - return 0;
> -}
> -
> -#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
> -
> #endif /* _LINUX_INTEGRITY_H */
> diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
> index 895f4b9ce8c6..de603cf42ac7 100644
> --- a/security/integrity/digsig_asymmetric.c
> +++ b/security/integrity/digsig_asymmetric.c
> @@ -132,26 +132,3 @@ int asymmetric_verify(struct key *keyring, const char *sig,
> pr_debug("%s() = %d\n", __func__, ret);
> return ret;
> }
> -
> -/**
> - * integrity_kernel_module_request - prevent crypto-pkcs1pad(rsa,*) requests
> - * @kmod_name: kernel module name
> - *
> - * We have situation, when public_key_verify_signature() in case of RSA
> - * algorithm use alg_name to store internal information in order to
> - * construct an algorithm on the fly, but crypto_larval_lookup() will try
> - * to use alg_name in order to load kernel module with same name.
> - * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules,
> - * we are safe to fail such module request from crypto_larval_lookup().
> - *
> - * In this way we prevent modprobe execution during digsig verification
> - * and avoid possible deadlock if modprobe and/or it's dependencies
> - * also signed with digsig.
> - */
> -int integrity_kernel_module_request(char *kmod_name)
> -{
> - if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0)
> - return -EINVAL;
> -
> - return 0;
> -}
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 02021ee467d3..3891b83efdb3 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -1091,6 +1091,39 @@ int ima_measure_critical_data(const char *event_label,
> }
> EXPORT_SYMBOL_GPL(ima_measure_critical_data);
>
> +#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
> +
> +/**
> + * ima_kernel_module_request - Prevent crypto-pkcs1pad(rsa,*) requests
> + * @kmod_name: kernel module name
> + *
> + * Avoid a verification loop where verifying the signature of the modprobe
> + * binary requires executing modprobe itself. Since the modprobe iint->mutex
> + * is already held when the signature verification is performed, a deadlock
> + * occurs as soon as modprobe is executed within the critical region, since
> + * the same lock cannot be taken again.
> + *
> + * This happens when public_key_verify_signature(), in case of RSA algorithm,
> + * use alg_name to store internal information in order to construct an
> + * algorithm on the fly, but crypto_larval_lookup() will try to use alg_name
> + * in order to load a kernel module with same name.
> + *
> + * Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules,
> + * we are safe to fail such module request from crypto_larval_lookup(), and
> + * avoid the verification loop.
> + *
> + * Return: Zero if it is safe to load the kernel module, -EINVAL otherwise.
> + */
> +int ima_kernel_module_request(char *kmod_name)
> +{
> + if (strncmp(kmod_name, "crypto-pkcs1pad(rsa,", 20) == 0)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
> +
> static int __init init_ima(void)
> {
> int error;
> diff --git a/security/security.c b/security/security.c
> index f8d9ebeb4c31..48dc3db4c834 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -3250,7 +3250,7 @@ int security_kernel_module_request(char *kmod_name)
> ret = call_int_hook(kernel_module_request, 0, kmod_name);
> if (ret)
> return ret;
> - return integrity_kernel_module_request(kmod_name);
> + return ima_kernel_module_request(kmod_name);
> }
>
> /**
> On Feb 15, 2024, at 3:30 AM, Roberto Sassu <[email protected]> wrote:
>
> From: Roberto Sassu <[email protected]>
>
> The patch set applies on top of lsm/next, commit 97280fa1ed94 ("Automated
> merge of 'dev' into 'next'").
I have tested the ima appraisal portion and have not observed any regressions with
this series. For that part of the code, if you want, feel free to add:
Tested-by: Eric Snowberg <[email protected]>