fanotify: Fix crash in fanotify_init(2)
The rrror handling in fanotify_init(2) is buggy and overwrites 'fd'
before calling put_unused_fd() leading to possible access beyond the end
of fd bitmap. Fix it.
Reported-by: syzbot+6a3aa63412255587b21b@syzkaller.appspotmail.com
Fixes: ebe559609d78 ("fs: get rid of __FMODE_NONOTIFY kludge")
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 19435cd..6ff94e3 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1624,8 +1624,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
file = anon_inode_getfile_fmode("[fanotify]", &fanotify_fops, group,
f_flags, FMODE_NONOTIFY);
if (IS_ERR(file)) {
- fd = PTR_ERR(file);
put_unused_fd(fd);
+ fd = PTR_ERR(file);
goto out_destroy_group;
}
fd_install(fd, file);
