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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 96BC4C2F3BE for ; Mon, 21 Jan 2019 13:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6180520861 for ; Mon, 21 Jan 2019 13:49:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078578; bh=hJrvBYLj44Az9REFkiWELJ27HIlauBaiQQamZw54Oq8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bCfDxpuUN7rdrM3btPJ5kdxIurY8sZ54idlh1/fOOFg5xcJo98ExdKYnkwFPjtM+f P9k9OW73GN5zRatV1wGLx3R7ZFscBbSTLAINIxjQyvEY/zqEvX8u/MerrOdrH5ika/ DVJFAvqMX8cm5YvN0UvJ6QxMjxqapPEj2Ko92FQw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730295AbfAUNtg (ORCPT ); Mon, 21 Jan 2019 08:49:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:60198 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730261AbfAUNtd (ORCPT ); Mon, 21 Jan 2019 08:49:33 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 379942087F; Mon, 21 Jan 2019 13:49:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548078572; bh=hJrvBYLj44Az9REFkiWELJ27HIlauBaiQQamZw54Oq8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ODMylDqbZypqQH0S+rGSsb/TGcII82ttcU2B1qBzsmnG9wf+wHnrd5qgXSsLQd84C ijOfHWZbTyGqBZtu3MiEj8Xuacyhp97q30INjgf6dBosdUdOIVbO7qZnUyXiGpFjUs WUreqU47Sqxam97wzzqT6QZmIdbNnSFGsKwVUqyE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hans Verkuil , syzbot+be93025dd45dccd8923c@syzkaller.appspotmail.com, Hans Verkuil , Mauro Carvalho Chehab Subject: [PATCH 4.20 078/111] media: vb2: vb2_mmap: move lock up Date: Mon, 21 Jan 2019 14:43:12 +0100 Message-Id: <20190121122504.957846226@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190121122455.819406896@linuxfoundation.org> References: <20190121122455.819406896@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans Verkuil commit cd26d1c4d1bc947b56ae404998ae2276df7b39b7 upstream. If a filehandle is dup()ped, then it is possible to close it from one fd and call mmap from the other. This creates a race condition in vb2_mmap where it is using queue data that __vb2_queue_free (called from close()) is in the process of releasing. By moving up the mutex_lock(mmap_lock) in vb2_mmap this race is avoided since __vb2_queue_free is called with the same mutex locked. So vb2_mmap now reads consistent buffer data. Signed-off-by: Hans Verkuil Reported-by: syzbot+be93025dd45dccd8923c@syzkaller.appspotmail.com Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/common/videobuf2/videobuf2-core.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -2146,9 +2146,13 @@ int vb2_mmap(struct vb2_queue *q, struct return -EINVAL; } } + + mutex_lock(&q->mmap_lock); + if (vb2_fileio_is_active(q)) { dprintk(1, "mmap: file io in progress\n"); - return -EBUSY; + ret = -EBUSY; + goto unlock; } /* @@ -2156,7 +2160,7 @@ int vb2_mmap(struct vb2_queue *q, struct */ ret = __find_plane_by_offset(q, off, &buffer, &plane); if (ret) - return ret; + goto unlock; vb = q->bufs[buffer]; @@ -2172,8 +2176,9 @@ int vb2_mmap(struct vb2_queue *q, struct return -EINVAL; } - mutex_lock(&q->mmap_lock); ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma); + +unlock: mutex_unlock(&q->mmap_lock); if (ret) return ret;