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authorJan Kara <jack@suse.cz>2016-09-19 14:44:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-19 15:36:17 -0700
commit96d41019e3ac55f6f0115b0ce97e4f24a3d636d2 (patch)
tree4178f8feee6258da1c08f27de55af8de3f2b5af2 /include
parent12703dbfeb15402260e7554d32a34ac40c233990 (diff)
downloadlinux-96d41019e3ac55f6f0115b0ce97e4f24a3d636d2.tar.bz2
fanotify: fix list corruption in fanotify_get_response()
fanotify_get_response() calls fsnotify_remove_event() when it finds that group is being released from fanotify_release() (bypass_perm is set). However the event it removes need not be only in the group's notification queue but it can have already moved to access_list (userspace read the event before closing the fanotify instance fd) which is protected by a different lock. Thus when fsnotify_remove_event() races with fanotify_release() operating on access_list, the list can get corrupted. Fix the problem by moving all the logic removing permission events from the lists to one place - fanotify_release(). Fixes: 5838d4442bd5 ("fanotify: fix double free of pending permission events") Link: http://lkml.kernel.org/r/1473797711-14111-3-git-send-email-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/fsnotify_backend.h3
1 files changed, 0 insertions, 3 deletions
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 40a9e99de703..7268ed076be8 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -180,7 +180,6 @@ struct fsnotify_group {
spinlock_t access_lock;
struct list_head access_list;
wait_queue_head_t access_waitq;
- atomic_t bypass_perm;
#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
int f_flags;
unsigned int max_marks;
@@ -307,8 +306,6 @@ extern int fsnotify_add_event(struct fsnotify_group *group,
struct fsnotify_event *event,
int (*merge)(struct list_head *,
struct fsnotify_event *));
-/* Remove passed event from groups notification queue */
-extern void fsnotify_remove_event(struct fsnotify_group *group, struct fsnotify_event *event);
/* true if the group notification queue is empty */
extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
/* return, but do not dequeue the first event on the notification queue */