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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 A7995C18E7C for ; Wed, 22 May 2019 08:35:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B224204EC for ; Wed, 22 May 2019 08:35:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KB8t9RLG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728542AbfEVIe6 (ORCPT ); Wed, 22 May 2019 04:34:58 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:41238 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728406AbfEVIe5 (ORCPT ); Wed, 22 May 2019 04:34:57 -0400 Received: by mail-pl1-f194.google.com with SMTP id f12so716848plt.8; Wed, 22 May 2019 01:34:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=aa0JQwY4uqqpbNq959wh0RxA5zY61j1J+l6728Nh0xs=; b=KB8t9RLG/XAQuV0B2FyA+h6KuulHMJdc0VO5dfFxoQOcLju9pBzcuEN3mPzaHMFjaB ltQFcvgoLeZi7ox1wz358ZekzNH3Nx0AYlgrRlwYcmA26Kr0bZRds4BrEBEKeg6f6CH5 vcfN2FqZQDsg1qFuKSfLOYiDy92agibityXYDsbcvvmhDMNu4QdIs5trn8nxbwF0Jwp5 HrDJYgW0mi8EZkqENcC61L+dn9XfaR9A8vRQmFtQMTyALTyolOm5R18kMOtIRhxB12X+ jiQWfTSFW0S7wxb23svwJ1bmmxeR4hYh1uTIHSG92DYzVJ9AvQdONAw4rBlWqKNx+S7h dJug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=aa0JQwY4uqqpbNq959wh0RxA5zY61j1J+l6728Nh0xs=; b=O3UMha+9O3o1B0u/yskp6eC+iwWrTmbRVrU3C+Nxgs0G6CJAzST64DFWXFoS5/U+Jq om38rYdbkN+MsYWRtFHgFFR3MPqhZ8z4l/392itiuOxpghEoCU19HVouXaTm/ITtILA1 R5gRut0lqzmW2NFyMbhXn0ThtZMwsFN8DjeDvav1vgqYFxx86cbXylJejnXlkgE1XWQc WTdkvP71su/Gt1cqbnckfiiBE3dAeCV/SAYzHf0vMQgnWnPm/D3eFjc/3skFMPQUDhQY vnEdDXNVSl+G7dv6uYjH5mFeJB+6d21Dw/RhtGd+Hmt2Nma1o7DKnBsKTcStov4TdliO 82gQ== X-Gm-Message-State: APjAAAXT0CcVCCz4J7y0xS/E0nScCBRN+nIMwcFv7tapDK5hE81/MUle B/CzhU9nUNAxfQ8sM8xjtMg= X-Google-Smtp-Source: APXvYqyLmLXdPtAfGmXKNp/xMdMdCWCm7/beFiMKuIxmongEL96HvIGFip9kZFfLDHMAT1pm8o27yQ== X-Received: by 2002:a17:902:a510:: with SMTP id s16mr88921899plq.334.1558514096893; Wed, 22 May 2019 01:34:56 -0700 (PDT) Received: from bnva-HP-Pavilion-g6-Notebook-PC.domain.name ([117.241.200.143]) by smtp.gmail.com with ESMTPSA id n13sm27870900pgh.6.2019.05.22.01.34.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 May 2019 01:34:56 -0700 (PDT) From: Vandana BN To: hverkuil@xs4all.nl, royale@zerezo.com, mchehab@kernel.org, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, Vandana BN Subject: [PATCH v2] media:usb:zr364xx:Fix KASAN:null-ptr-deref Read in zr364xx_vidioc_querycap Date: Wed, 22 May 2019 14:04:15 +0530 Message-Id: <20190522083415.9252-1-bnvandana@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190521181535.7974-1-bnvandana@gmail.com> References: <20190521181535.7974-1-bnvandana@gmail.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 --- v2 - removed else part as cap->card is already zeroed. drivers/media/usb/zr364xx/zr364xx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/zr364xx/zr364xx.c b/drivers/media/usb/zr364xx/zr364xx.c index 96fee8d5b865..cd2bc9ed0cd9 100644 --- a/drivers/media/usb/zr364xx/zr364xx.c +++ b/drivers/media/usb/zr364xx/zr364xx.c @@ -703,7 +703,8 @@ static int zr364xx_vidioc_querycap(struct file *file, void *priv, struct zr364xx_camera *cam = video_drvdata(file); strscpy(cap->driver, DRIVER_DESC, sizeof(cap->driver)); - strscpy(cap->card, cam->udev->product, sizeof(cap->card)); + if (cam->udev->product) + strscpy(cap->card, cam->udev->product, sizeof(cap->card)); strscpy(cap->bus_info, dev_name(&cam->udev->dev), sizeof(cap->bus_info)); cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | -- 2.17.1