fanotify: if set by user unset FMODE_NONOTIFY before fsnotify_perm() is called

Unsetting FMODE_NONOTIFY in fsnotify_open() is too late, since fsnotify_perm()
is called before. If FMODE_NONOTIFY is set fsnotify_perm() will skip permission
checks, so a user can still disable permission checks by setting this flag
in an open() call.
This patch corrects this by unsetting the flag before fsnotify_perm is called.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 5c185fa27089..b10bcdeaef76 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -235,9 +235,6 @@ static inline void fsnotify_open(struct file *file)
         if (S_ISDIR(inode->i_mode))
                 mask |= FS_ISDIR;
 
-        /* FMODE_NONOTIFY must never be set from user */
-        file->f_mode &= ~FMODE_NONOTIFY;
-
         fsnotify_parent(path, NULL, mask);
         fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 }