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=-5.6 required=3.0 tests=DATE_IN_PAST_06_12, 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=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 2121CC7618B for ; Thu, 25 Jul 2019 05:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA7C220657 for ; Thu, 25 Jul 2019 05:50:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564033826; bh=OgzOyEycRsQ5tZXTbgiVPzNADZxiQiXmkuy7t8sX45E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vseD81faNObooqJds+IogvL0+HBwTr6giDMcSu9fS+fRPuIxI5K8pHOHmmtRSQZBO lusTehZMDrDX5wB/2N2eyN6giakOzQ03y55ZkkUwfnQAgCHgKwRICtgWwl697nRs8A UJX8K8aDgoReMi0GXzw/odBH1fQoVBSx88SqaMTk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729277AbfGYFuY (ORCPT ); Thu, 25 Jul 2019 01:50:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:58034 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404865AbfGYFnE (ORCPT ); Thu, 25 Jul 2019 01:43:04 -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 7670B21850; Thu, 25 Jul 2019 05:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564033384; bh=OgzOyEycRsQ5tZXTbgiVPzNADZxiQiXmkuy7t8sX45E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ldxotr/H4t9mBA7PRPwRpAuZEI9ag9RvTrdWKkgNicVMX0NUGwl965/5YYWyK+Odf UKKIgwSMCrjpIWo+ItDl24E4Imo3OWFX+/sRix91M553UWZLgcu/6T1sxfbu6LMIvI lXT1QMSIWwfpwc2JRRszsWuaUXLTpkycr4Reet6Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Grant Hernandez , Dmitry Torokhov Subject: [PATCH 4.19 189/271] Input: gtco - bounds check collection indent level Date: Wed, 24 Jul 2019 21:20:58 +0200 Message-Id: <20190724191711.317742016@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191655.268628197@linuxfoundation.org> References: <20190724191655.268628197@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] = '-';