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=-6.8 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,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 B51A9C433FF for ; Fri, 2 Aug 2019 09:44:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 902E3206A2 for ; Fri, 2 Aug 2019 09:44:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739069; bh=OgzOyEycRsQ5tZXTbgiVPzNADZxiQiXmkuy7t8sX45E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=indgDFXRC5j83Jm7iAs3jzZrzNQgD0iFh8tsiLop1U461JbkQxxPSnOHdm6hw4I2B MFxnDiv052DMcaJKpuFGQOLBmVF63rNkHGkgKts08mjqONjmuvwAjWK5IRfkJDjFp1 0O2qWVDRVzV5XNIH/AnB+Jcc9zAfeTqsfBUC0kxw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405250AbfHBJo2 (ORCPT ); Fri, 2 Aug 2019 05:44:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:47742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404851AbfHBJoX (ORCPT ); Fri, 2 Aug 2019 05:44:23 -0400 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 0FDCD2087E; Fri, 2 Aug 2019 09:44:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739062; bh=OgzOyEycRsQ5tZXTbgiVPzNADZxiQiXmkuy7t8sX45E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A3vyW8iKLVpCmKIdrce19s3/WM9QJJbsq4QddVquNx3BzQSJP6D8+sQyrN+42byzE Y47c7nt3H5RJsaATDHvZptsyyG3/qVIpZ4x7pGXNYtagOwke6eRdAcCOoSpL6zqw3U +zL9iRZXEZB5lk7iRO64ZT0FX8sijg27vO8NADOo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Grant Hernandez , Dmitry Torokhov Subject: [PATCH 4.9 083/223] Input: gtco - bounds check collection indent level Date: Fri, 2 Aug 2019 11:35:08 +0200 Message-Id: <20190802092244.354372737@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Grant Hernandez commit 2a017fd82c5402b3c8df5e3d6e5165d9e6147dc1 upstream. The GTCO tablet input driver configures itself from an HID report sent via USB during the initial enumeration process. Some debugging messages are generated during the parsing. A debugging message indentation counter is not bounds checked, leading to the ability for a specially crafted HID report to cause '-' and null bytes be written past the end of the indentation array. As long as the kernel has CONFIG_DYNAMIC_DEBUG enabled, this code will not be optimized out. This was discovered during code review after a previous syzkaller bug was found in this driver. Signed-off-by: Grant Hernandez Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- drivers/input/tablet/gtco.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) --- a/drivers/input/tablet/gtco.c +++ b/drivers/input/tablet/gtco.c @@ -78,6 +78,7 @@ Scott Hill shill@gtcocalcomp.com /* Max size of a single report */ #define REPORT_MAX_SIZE 10 +#define MAX_COLLECTION_LEVELS 10 /* Bitmask whether pen is in range */ @@ -223,8 +224,7 @@ static void parse_hid_report_descriptor( char maintype = 'x'; char globtype[12]; int indent = 0; - char indentstr[10] = ""; - + char indentstr[MAX_COLLECTION_LEVELS + 1] = { 0 }; dev_dbg(ddev, "======>>>>>>PARSE<<<<<<======\n"); @@ -350,6 +350,13 @@ static void parse_hid_report_descriptor( case TAG_MAIN_COL_START: maintype = 'S'; + if (indent == MAX_COLLECTION_LEVELS) { + dev_err(ddev, "Collection level %d would exceed limit of %d\n", + indent + 1, + MAX_COLLECTION_LEVELS); + break; + } + if (data == 0) { dev_dbg(ddev, "======>>>>>> Physical\n"); strcpy(globtype, "Physical"); @@ -369,8 +376,15 @@ static void parse_hid_report_descriptor( break; case TAG_MAIN_COL_END: - dev_dbg(ddev, "<<<<<<======\n"); maintype = 'E'; + + if (indent == 0) { + dev_err(ddev, "Collection level already at zero\n"); + break; + } + + dev_dbg(ddev, "<<<<<<======\n"); + indent--; for (x = 0; x < indent; x++) indentstr[x] = '-';