From 3587b1b097d70c2eb9fee95ea7995d13c05f66e5 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 18 Nov 2012 19:19:00 +0000 Subject: [PATCH] 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 Signed-off-by: Al Viro Signed-off-by: Linus Torvalds --- fs/notify/fanotify/fanotify_user.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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: -- 2.20.1