]> git.openfabrics.org - ~shefty/rdma-dev.git/commitdiff
fanotify: fix FAN_Q_OVERFLOW case of fanotify_read()
authorAl Viro <viro@ZenIV.linux.org.uk>
Sun, 18 Nov 2012 19:19:00 +0000 (19:19 +0000)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sun, 18 Nov 2012 19:30:00 +0000 (09:30 -1000)
If the FAN_Q_OVERFLOW bit set in event->mask, the fanotify event
metadata will not contain a valid file descriptor, but
copy_event_to_user() didn't check for that, and unconditionally does a
fd_install() on the file descriptor.

Which in turn will cause a BUG_ON() in __fd_install().

Introduced by commit 352e3b249284 ("fanotify: sanitize failure exits in
copy_event_to_user()")

Mea culpa - missed that path ;-/

Reported-by: Alex Shi <lkml.alex@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/notify/fanotify/fanotify_user.c

index 721d692fa8d4a20dd5bf593d3f732d8b3f913261..6fcaeb8c902e4c3bc862c6c81db0a884068274b7 100644 (file)
@@ -258,7 +258,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
        if (ret)
                goto out_close_fd;
 
-       fd_install(fd, f);
+       if (fd != FAN_NOFD)
+               fd_install(fd, f);
        return fanotify_event_metadata.event_len;
 
 out_close_fd: