[PATCH 4/9] ima: Move ima_file_free() into LSM

Kees Cook
2022-10-13T22:37:29Z

The file_free_security hook already exists for managing notification of
released files. Use the LSM hook instead of open-coded stacking.

Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Petr Vorel <pvorel@suse.cz>
Cc: Jonathan McDowell <noodles@fb.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: linux-integrity@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/file_table.c | 1 -
include/linux/ima.h | 6 ------
security/integrity/ima/ima_main.c | 3 ++-
3 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 99c6796c9f28..fa707d221a43 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -311,7 +311,6 @@ static void __fput(struct file *file)
eventpoll_release(file);
locks_remove_file(file);

- ima_file_free(file);
if (unlikely(file->f_flags & FASYNC)) {
if (file->f_op->fasync)
file->f_op->fasync(-1, file, 0);
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 6dc5143f89f2..9f18df366064 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -19,7 +19,6 @@ extern enum hash_algo ima_get_current_hash_algo(void);
extern int ima_file_check(struct file *file, int mask);
extern void ima_post_create_tmpfile(struct user_namespace *mnt_userns,
struct inode *inode);
-extern void ima_file_free(struct file *file);
extern void ima_post_path_mknod(struct user_namespace *mnt_userns,
struct dentry *dentry);
extern int ima_file_hash(struct file *file, char *buf, size_t buf_size);
@@ -56,11 +55,6 @@ static inline void ima_post_create_tmpfile(struct user_namespace *mnt_userns,
{
}

-static inline void ima_file_free(struct file *file)
-{
- return;
-}
-
static inline void ima_post_path_mknod(struct user_namespace *mnt_userns,
struct dentry *dentry)
{
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index b3b79d030a67..94379ba40b58 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -183,7 +183,7 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint,
*
* Flag files that changed, based on i_version
*/
-void ima_file_free(struct file *file)
+static void ima_file_free(struct file *file)
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint;
@@ -1085,6 +1085,7 @@ static struct security_hook_list ima_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
LSM_HOOK_INIT(mmap_file, ima_file_mmap),
LSM_HOOK_INIT(file_mprotect, ima_file_mprotect),
+ LSM_HOOK_INIT(file_free_security, ima_file_free),
LSM_HOOK_INIT(kernel_read_file, ima_read_file),
LSM_HOOK_INIT(kernel_post_read_file, ima_post_read_file),
LSM_HOOK_INIT(kernel_load_data, ima_load_data),
--
2.34.1