From a0fbcaf9993ea291955ead3dac4b52457b3ec799 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Tue, 1 May 2018 13:12:14 +0900 Subject: fuse: don't keep dead fuse_conn at fuse_fill_super(). commit 543b8f8662fe6d21f19958b666ab0051af9db21a upstream. syzbot is reporting use-after-free at fuse_kill_sb_blk() [1]. Since sb->s_fs_info field is not cleared after fc was released by fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds already released fc and tries to hold the lock. Fix this by clearing sb->s_fs_info field after calling fuse_conn_put(). [1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db Signed-off-by: Tetsuo Handa Reported-by: syzbot Fixes: 3b463ae0c626 ("fuse: invalidation reverse calls") Cc: John Muir Cc: Csaba Henk Cc: Anand Avati Cc: # v2.6.31 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/fuse/inode.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 6fe6a88ecb4a..f95e1d49b048 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1184,6 +1184,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) err_put_conn: fuse_bdi_destroy(fc); fuse_conn_put(fc); + sb->s_fs_info = NULL; err_fput: fput(file); err: -- cgit v1.2.3