[PATCH v3 22/25] ima: Move IMA-Appraisal to LSM infrastructure

Roberto Sassu
2023-09-04T13:42:50Z

From: Roberto Sassu <roberto.sassu@huawei.com>

Do the registration of IMA-Appraisal functions separately from the rest of
IMA functions, as appraisal is a separate feature not necessarily enabled
in the kernel configuration.

Reuse the same approach as for other IMA functions, remove hardcoded calls
from the LSM infrastructure or the other places, declare the functions as
static and register them as hook implementations in
init_ima_appraise_lsm(), called by init_ima_lsm() to chain the
initialization.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
fs/attr.c | 2 -
include/linux/ima.h | 55 ---------------------------
security/integrity/ima/ima.h | 5 +++
security/integrity/ima/ima_appraise.c | 38 +++++++++++++-----
security/integrity/ima/ima_main.c | 1 +
security/security.c | 13 -------
6 files changed, 35 insertions(+), 79 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index 3c309eb456c6..63fb60195409 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -17,7 +17,6 @@
#include <linux/filelock.h>
#include <linux/security.h>
#include <linux/evm.h>
-#include <linux/ima.h>

#include "internal.h"

@@ -487,7 +486,6 @@ 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);
- ima_inode_post_setattr(idmap, dentry, ia_valid);
evm_inode_post_setattr(idmap, dentry, ia_valid);
}

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 58591b5cbdb4..586e2e18e494 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -98,66 +98,11 @@ static inline void ima_add_kexec_buffer(struct kimage *image)

#ifdef CONFIG_IMA_APPRAISE
extern bool is_ima_appraise_enabled(void);
-extern void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, int ia_valid);
-int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *xattr_name, const void *xattr_value,
- size_t xattr_value_len, int flags);
-extern int ima_inode_set_acl(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *acl_name,
- struct posix_acl *kacl);
-static inline int ima_inode_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- return ima_inode_set_acl(idmap, dentry, acl_name, NULL);
-}
-
-int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *xattr_name);
#else
static inline bool is_ima_appraise_enabled(void)
{
return 0;
}
-
-static inline void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, int ia_valid)
-{
- return;
-}
-
-static inline int ima_inode_setxattr(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *xattr_name,
- const void *xattr_value,
- size_t xattr_value_len,
- int flags)
-{
- return 0;
-}
-
-static inline int ima_inode_set_acl(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *acl_name,
- struct posix_acl *kacl)
-{
-
- return 0;
-}
-
-static inline int ima_inode_removexattr(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *xattr_name)
-{
- return 0;
-}
-
-static inline int ima_inode_remove_acl(struct mnt_idmap *idmap,
- struct dentry *dentry,
- const char *acl_name)
-{
- return 0;
-}
#endif /* CONFIG_IMA_APPRAISE */

#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index c0412100023e..d19aa9c068da 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -334,6 +334,7 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
int xattr_len);
int ima_read_xattr(struct dentry *dentry,
struct evm_ima_xattr_data **xattr_value, int xattr_len);
+void __init init_ima_appraise_lsm(void);

#else
static inline int ima_check_blacklist(struct integrity_iint_cache *iint,
@@ -385,6 +386,10 @@ static inline int ima_read_xattr(struct dentry *dentry,
return 0;
}

+static inline void __init init_ima_appraise_lsm(void)
+{
+}
+
#endif /* CONFIG_IMA_APPRAISE */

#ifdef CONFIG_IMA_APPRAISE_MODSIG
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index c35e3537eb87..8fe6ea70f02b 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -634,8 +634,8 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
* This function is called from notify_change(), which expects the caller
* to lock the inode's i_mutex.
*/
-void ima_inode_post_setattr(struct mnt_idmap *idmap,
- struct dentry *dentry, int ia_valid)
+static void ima_inode_post_setattr(struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
{
struct inode *inode = d_backing_inode(dentry);
struct integrity_iint_cache *iint;
@@ -748,9 +748,9 @@ static int validate_hash_algo(struct dentry *dentry,
return -EACCES;
}

-int ima_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 ima_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 *xvalue = xattr_value;
int digsig = 0;
@@ -779,8 +779,8 @@ int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
return result;
}

-int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *acl_name, struct posix_acl *kacl)
+static int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name, struct posix_acl *kacl)
{
if (evm_revalidate_status(acl_name))
ima_reset_appraise_flags(d_backing_inode(dentry), 0);
@@ -788,8 +788,8 @@ int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
return 0;
}

-int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *xattr_name)
+static int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name)
{
int result;

@@ -801,3 +801,23 @@ int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
}
return result;
}
+
+static int ima_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name)
+{
+ return ima_inode_set_acl(idmap, dentry, acl_name, NULL);
+}
+
+static struct security_hook_list ima_appraise_hooks[] __ro_after_init = {
+ LSM_HOOK_INIT(inode_post_setattr, ima_inode_post_setattr),
+ LSM_HOOK_INIT(inode_setxattr, ima_inode_setxattr),
+ LSM_HOOK_INIT(inode_set_acl, ima_inode_set_acl),
+ LSM_HOOK_INIT(inode_removexattr, ima_inode_removexattr),
+ LSM_HOOK_INIT(inode_remove_acl, ima_inode_remove_acl),
+};
+
+void __init init_ima_appraise_lsm(void)
+{
+ security_add_hooks(ima_appraise_hooks, ARRAY_SIZE(ima_appraise_hooks),
+ "integrity");
+}
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 0e4f882fcdce..c31e11a5bc31 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1141,6 +1141,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = {
void __init init_ima_lsm(void)
{
security_add_hooks(ima_hooks, ARRAY_SIZE(ima_hooks), "integrity");
+ init_ima_appraise_lsm();
}

late_initcall(init_ima); /* Start IMA after the TPM is available */
diff --git a/security/security.c b/security/security.c
index 0b196d3f01b8..eb686f9471ea 100644
--- a/security/security.c
+++ b/security/security.c
@@ -20,7 +20,6 @@
#include <linux/kernel_read_file.h>
#include <linux/lsm_hooks.h>
#include <linux/integrity.h>
-#include <linux/ima.h>
#include <linux/evm.h>
#include <linux/fsnotify.h>
#include <linux/mman.h>
@@ -2217,9 +2216,6 @@ int security_inode_setxattr(struct mnt_idmap *idmap,

if (ret == 1)
ret = cap_inode_setxattr(dentry, name, value, size, flags);
- if (ret)
- return ret;
- ret = ima_inode_setxattr(idmap, dentry, name, value, size, flags);
if (ret)
return ret;
return evm_inode_setxattr(idmap, dentry, name, value, size, flags);
@@ -2247,9 +2243,6 @@ int security_inode_set_acl(struct mnt_idmap *idmap,
return 0;
ret = call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name,
kacl);
- if (ret)
- return ret;
- ret = ima_inode_set_acl(idmap, dentry, acl_name, kacl);
if (ret)
return ret;
return evm_inode_set_acl(idmap, dentry, acl_name, kacl);
@@ -2310,9 +2303,6 @@ int security_inode_remove_acl(struct mnt_idmap *idmap,
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;
- ret = ima_inode_remove_acl(idmap, dentry, acl_name);
if (ret)
return ret;
return evm_inode_remove_acl(idmap, dentry, acl_name);
@@ -2412,9 +2402,6 @@ 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;
- ret = ima_inode_removexattr(idmap, dentry, name);
if (ret)
return ret;
return evm_inode_removexattr(idmap, dentry, name);
--
2.34.1