From patchwork Wed Jan 22 09:28:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 233474 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,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 42ED1C47409 for ; Wed, 22 Jan 2020 09:54:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DA5120704 for ; Wed, 22 Jan 2020 09:54:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579686869; bh=jgYMrh40B1NE3FzhhtO8edLHzqlzIJkJEvBtjFq4TRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a/6OTXTBtM2MoWXFs68b3kGkPk9il3airrDIuXgbqyp4KBoM3J4OplITWZCHJJ4ph 8Pbi4j94dl7N2hrnfgZE5e2UMPJXwdQ4+sKsTZO14St+ol0rvfoy1ysrGcjkWhBWFk X3kszIChWphhPpnUztVhqdFdE58dRUz3pDcu3zy0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729418AbgAVJeH (ORCPT ); Wed, 22 Jan 2020 04:34:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:48436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729833AbgAVJeG (ORCPT ); Wed, 22 Jan 2020 04:34:06 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 30FED24680; Wed, 22 Jan 2020 09:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579685645; bh=jgYMrh40B1NE3FzhhtO8edLHzqlzIJkJEvBtjFq4TRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DF83vKx/Wsv75Jh9yGkI1XQp6INbsz69cCUr69CvDVYwYJyDbokJh9IJBSa98VI0m thml2qkFpi9wQFpd89IpunGQHGXsFwnTh6jm6j2TEpyx3pS4MXjCI/lRcsBI9eM+pg mnFQvc3hiYPmca8vB8h3uj5jE4lIWxeQnbe4MCc4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+66010012fd4c531a1a96@syzkaller.appspotmail.com, Vandana BN , Hans Verkuil , Mauro Carvalho Chehab , Ben Hutchings Subject: [PATCH 4.9 14/97] media: usb:zr364xx:Fix KASAN:null-ptr-deref Read in zr364xx_vidioc_querycap Date: Wed, 22 Jan 2020 10:28:18 +0100 Message-Id: <20200122092758.179998216@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122092755.678349497@linuxfoundation.org> References: <20200122092755.678349497@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vandana BN commit 5d2e73a5f80a5b5aff3caf1ec6d39b5b3f54b26e upstream. SyzKaller hit the null pointer deref while reading from uninitialized udev->product in zr364xx_vidioc_querycap(). ================================================================== BUG: KASAN: null-ptr-deref in read_word_at_a_time+0xe/0x20 include/linux/compiler.h:274 Read of size 1 at addr 0000000000000000 by task v4l_id/5287 CPU: 1 PID: 5287 Comm: v4l_id Not tainted 5.1.0-rc3-319004-g43151d6 #6 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xe8/0x16e lib/dump_stack.c:113 kasan_report.cold+0x5/0x3c mm/kasan/report.c:321 read_word_at_a_time+0xe/0x20 include/linux/compiler.h:274 strscpy+0x8a/0x280 lib/string.c:207 zr364xx_vidioc_querycap+0xb5/0x210 drivers/media/usb/zr364xx/zr364xx.c:706 v4l_querycap+0x12b/0x340 drivers/media/v4l2-core/v4l2-ioctl.c:1062 __video_do_ioctl+0x5bb/0xb40 drivers/media/v4l2-core/v4l2-ioctl.c:2874 video_usercopy+0x44e/0xf00 drivers/media/v4l2-core/v4l2-ioctl.c:3056 v4l2_ioctl+0x14e/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:364 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xced/0x12f0 fs/ioctl.c:696 ksys_ioctl+0xa0/0xc0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x74/0xb0 fs/ioctl.c:718 do_syscall_64+0xcf/0x4f0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3b56d8b347 Code: 90 90 90 48 8b 05 f1 fa 2a 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 90 90 90 90 90 90 90 90 90 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c1 fa 2a 00 31 d2 48 29 c2 64 RSP: 002b:00007ffe005d5d68 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f3b56d8b347 RDX: 00007ffe005d5d70 RSI: 0000000080685600 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400884 R13: 00007ffe005d5ec0 R14: 0000000000000000 R15: 0000000000000000 ================================================================== For this device udev->product is not initialized and accessing it causes a NULL pointer deref. The fix is to check for NULL before strscpy() and copy empty string, if product is NULL Reported-by: syzbot+66010012fd4c531a1a96@syzkaller.appspotmail.com Signed-off-by: Vandana BN Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab [bwh: Backported to 4.9: This function uses strlcpy() instead of strscpy()] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/zr364xx/zr364xx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/media/usb/zr364xx/zr364xx.c +++ b/drivers/media/usb/zr364xx/zr364xx.c @@ -711,7 +711,8 @@ static int zr364xx_vidioc_querycap(struc struct zr364xx_camera *cam = video_drvdata(file); strlcpy(cap->driver, DRIVER_DESC, sizeof(cap->driver)); - strlcpy(cap->card, cam->udev->product, sizeof(cap->card)); + if (cam->udev->product) + strlcpy(cap->card, cam->udev->product, sizeof(cap->card)); strlcpy(cap->bus_info, dev_name(&cam->udev->dev), sizeof(cap->bus_info)); cap->device_caps = V4L2_CAP_VIDEO_CAPTURE |