From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83A79C43441 for ; Sun, 11 Nov 2018 20:39:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51B45208A3 for ; Sun, 11 Nov 2018 20:39:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51B45208A3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730288AbeKLG26 (ORCPT ); Mon, 12 Nov 2018 01:28:58 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:49568 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729532AbeKLFsI (ORCPT ); Mon, 12 Nov 2018 00:48:08 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvsT-0000l8-AX; Sun, 11 Nov 2018 19:58:37 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsQ-0001Us-Nl; Sun, 11 Nov 2018 19:58:34 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Tetsuo Handa" , "Miklos Szeredi" , "syzbot" , "Anand Avati" , "Csaba Henk" , "John Muir" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 101/366] fuse: don't keep dead fuse_conn at fuse_fill_super(). In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Tetsuo Handa 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 Signed-off-by: Miklos Szeredi Signed-off-by: Ben Hutchings --- fs/fuse/inode.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1125,6 +1125,7 @@ static int fuse_fill_super(struct super_ err_put_conn: fuse_bdi_destroy(fc); fuse_conn_put(fc); + sb->s_fs_info = NULL; err_fput: fput(file); err: