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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 E12E8C7618F for ; Mon, 15 Jul 2019 13:49:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B13D92067C for ; Mon, 15 Jul 2019 13:49:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563198565; bh=G2ijCRlU75Uq7/diR/1R7m6j3QHIZv/xDOmFd6Y8dHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ii+vCUzjvYFWecVkKRQnW8eRPkCBhwjIefFemRYpEPloLzOdfJ1lXZ0HyTqAXde3x +kOiEhe9f6kbhHjdza0HPFcx1515z73y0VZfWLTr+sR2isXq9zYt4arBdcCkZwDbWo o4mRR4Ci7tuuqCi9nw8/15ZWY5FCQZgaoFA7s8oM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731718AbfGONtV (ORCPT ); Mon, 15 Jul 2019 09:49:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:32878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731711AbfGONtV (ORCPT ); Mon, 15 Jul 2019 09:49:21 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CFDE32081C; Mon, 15 Jul 2019 13:49:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563198559; bh=G2ijCRlU75Uq7/diR/1R7m6j3QHIZv/xDOmFd6Y8dHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ix5rILd0DrdcqyRkgZCJNVv6QRVNclBxsE4bdLXZ+8WcaJYtooHnORW6MmkQ8vyO6 qFw/xFU5ImDUlUyt7FWrv9avrUEsj3vEPaWWdMA1ndMxgJ+wU2oyVrIUJEZJiDmlBz wjFuKaIzKG2BmmO7FcZeuWhBFNKxDQO7jZavmOCo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vandana BN , syzbot+66010012fd4c531a1a96@syzkaller.appspotmail.com, Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin , linux-usb@vger.kernel.org, linux-media@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 045/249] media: usb:zr364xx:Fix KASAN:null-ptr-deref Read in zr364xx_vidioc_querycap Date: Mon, 15 Jul 2019 09:43:30 -0400 Message-Id: <20190715134655.4076-45-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715134655.4076-1-sashal@kernel.org> References: <20190715134655.4076-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Vandana BN [ Upstream commit 5d2e73a5f80a5b5aff3caf1ec6d39b5b3f54b26e ] 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 Signed-off-by: Sasha Levin --- 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 37a7992585df..48803eb773ed 100644 --- a/drivers/media/usb/zr364xx/zr364xx.c +++ b/drivers/media/usb/zr364xx/zr364xx.c @@ -694,7 +694,8 @@ 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 | -- 2.20.1