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authorElena Reshetova <elena.reshetova@intel.com>2017-05-02 10:16:05 -0400
committerPaul Moore <paul@paul-moore.com>2017-05-02 10:16:05 -0400
commitbd120ded6a6af61ad342a8a95b36b64bd1e2f9e6 (patch)
tree8e3c4a2e444669f6355c3ec69940f8489f5eecfd /kernel/audit_watch.c
parent9d2378f8c8f1a3fcfab681fd90c139d90dca7b69 (diff)
downloadlwn-bd120ded6a6af61ad342a8a95b36b64bd1e2f9e6.tar.gz
lwn-bd120ded6a6af61ad342a8a95b36b64bd1e2f9e6.zip
audit: convert audit_watch.count from atomic_t to refcount_t
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> [PM: fix subject line, add #include] Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'kernel/audit_watch.c')
-rw-r--r--kernel/audit_watch.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index e293165dd063..e0656bd63036 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -28,6 +28,7 @@
#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/netlink.h>
+#include <linux/refcount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
@@ -46,7 +47,7 @@
*/
struct audit_watch {
- atomic_t count; /* reference count */
+ refcount_t count; /* reference count */
dev_t dev; /* associated superblock device */
char *path; /* insertion path */
unsigned long ino; /* associated inode number */
@@ -111,12 +112,12 @@ static inline struct audit_parent *audit_find_parent(struct inode *inode)
void audit_get_watch(struct audit_watch *watch)
{
- atomic_inc(&watch->count);
+ refcount_inc(&watch->count);
}
void audit_put_watch(struct audit_watch *watch)
{
- if (atomic_dec_and_test(&watch->count)) {
+ if (refcount_dec_and_test(&watch->count)) {
WARN_ON(watch->parent);
WARN_ON(!list_empty(&watch->rules));
kfree(watch->path);
@@ -178,7 +179,7 @@ static struct audit_watch *audit_init_watch(char *path)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&watch->rules);
- atomic_set(&watch->count, 1);
+ refcount_set(&watch->count, 1);
watch->path = path;
watch->dev = AUDIT_DEV_UNSET;
watch->ino = AUDIT_INO_UNSET;