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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 4A997C10F00 for ; Tue, 12 Mar 2019 18:11:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D75A205C9 for ; Tue, 12 Mar 2019 18:11:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552414267; bh=w2Xxlh68/zivV7wNzMNtqyFnpEkid43RAbfolX9YNmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RQeC3Ji5mx4SX9ACi3m7u7afyTDEHSPFslW+AmH2ZHoOusROBcKfKxpQDodGWEUaz PDRu7AyaajMYeNTavrnXjo0d1+kkM8gnQY/GGwzj9nDzAMuFR7dXgQ4H8YNsltEaF+ l0JY8tP2hvPmQm4g4iEHY6UFJTwL8+tgflMMA9+Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727095AbfCLRLp (ORCPT ); Tue, 12 Mar 2019 13:11:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:45420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727047AbfCLRLk (ORCPT ); Tue, 12 Mar 2019 13:11:40 -0400 Received: from localhost (unknown [104.133.8.98]) (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 9E339217F5; Tue, 12 Mar 2019 17:11:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552410699; bh=w2Xxlh68/zivV7wNzMNtqyFnpEkid43RAbfolX9YNmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hdJYq74ZGjN7NLyymcrayWVF07MaUBK5xhVZnyRT6kncIMAFKBpLQHxqaXmIUNv4L ohXLNlOLNmyAVNWyk2hx2TnsDB6OOsAJKSMIvyPpnevFJyKhC/YdQ9P/hi2Jun1rEa l4Gv2jZTJz8sXw+9h29cv7skGbtIUsGSIh/VOMe0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Alistair Strachan , Laurent Pinchart , Mauro Carvalho Chehab Subject: [PATCH 4.20 001/171] media: uvcvideo: Fix type check leading to overflow Date: Tue, 12 Mar 2019 10:06:21 -0700 Message-Id: <20190312170347.997250075@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190312170347.868927101@linuxfoundation.org> References: <20190312170347.868927101@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: Alistair Strachan commit 47bb117911b051bbc90764a8bff96543cbd2005f upstream. When initially testing the Camera Terminal Descriptor wTerminalType field (buffer[4]), no mask is used. Later in the function, the MSB is overloaded to store the descriptor subtype, and so a mask of 0x7fff is used to check the type. If a descriptor is specially crafted to set this overloaded bit in the original wTerminalType field, the initial type check will fail (falling through, without adjusting the buffer size), but the later type checks will pass, assuming the buffer has been made suitably large, causing an overflow. Avoid this problem by checking for the MSB in the wTerminalType field. If the bit is set, assume the descriptor is bad, and abort parsing it. Originally reported here: https://groups.google.com/forum/#!topic/syzkaller/Ot1fOE6v1d8 A similar (non-compiling) patch was provided at that time. Reported-by: syzbot Signed-off-by: Alistair Strachan Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/uvc/uvc_driver.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1065,11 +1065,19 @@ static int uvc_parse_standard_control(st return -EINVAL; } - /* Make sure the terminal type MSB is not null, otherwise it - * could be confused with a unit. + /* + * Reject invalid terminal types that would cause issues: + * + * - The high byte must be non-zero, otherwise it would be + * confused with a unit. + * + * - Bit 15 must be 0, as we use it internally as a terminal + * direction flag. + * + * Other unknown types are accepted. */ type = get_unaligned_le16(&buffer[4]); - if ((type & 0xff00) == 0) { + if ((type & 0x7f00) == 0 || (type & 0x8000) != 0) { uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol " "interface %d INPUT_TERMINAL %d has invalid " "type 0x%04x, skipping\n", udev->devnum,