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| author | Al Viro <viro@ZenIV.linux.org.uk> | 2012-11-18 19:19:00 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-11-18 09:30:00 -1000 |
| commit | 3587b1b097d70c2eb9fee95ea7995d13c05f66e5 (patch) | |
| tree | 71f29d988cb6a1ac7f1c258dc003a9d252ea72f6 | |
| parent | 8d938105e432fe0e9f5163147e9c113190bd9d32 (diff) | |
| download | lwn-3587b1b097d70c2eb9fee95ea7995d13c05f66e5.tar.gz lwn-3587b1b097d70c2eb9fee95ea7995d13c05f66e5.zip | |
fanotify: fix FAN_Q_OVERFLOW case of fanotify_read()
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>
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 721d692fa8d4..6fcaeb8c902e 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -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: |