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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 E1F0EC65BAF for ; Sun, 9 Dec 2018 22:11:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A93C02081F for ; Sun, 9 Dec 2018 22:11:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A93C02081F 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 S1728097AbeLIWLy (ORCPT ); Sun, 9 Dec 2018 17:11:54 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37732 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727603AbeLIWLv (ORCPT ); Sun, 9 Dec 2018 17:11:51 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW73L-0002il-Gn; Sun, 09 Dec 2018 21:55:55 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72a-0003I4-PE; Sun, 09 Dec 2018 21:55:08 +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, "Andrey Ryabinin" , "Miklos Szeredi" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 074/328] fuse: Don't access pipe->buffers without pipe_lock() In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 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 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andrey Ryabinin commit a2477b0e67c52f4364a47c3ad70902bc2a61bd4c upstream. fuse_dev_splice_write() reads pipe->buffers to determine the size of 'bufs' array before taking the pipe_lock(). This is not safe as another thread might change the 'pipe->buffers' between the allocation and taking the pipe_lock(). So we end up with too small 'bufs' array. Move the bufs allocations inside pipe_lock()/pipe_unlock() to fix this. Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device") Signed-off-by: Andrey Ryabinin Signed-off-by: Miklos Szeredi [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- fs/fuse/dev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1913,11 +1913,14 @@ static ssize_t fuse_dev_splice_write(str if (!fc) return -EPERM; + pipe_lock(pipe); + bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); - if (!bufs) + if (!bufs) { + pipe_unlock(pipe); return -ENOMEM; + } - pipe_lock(pipe); nbuf = 0; rem = 0; for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)