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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 0A9BDC43387 for ; Wed, 19 Dec 2018 15:19:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D94EC218D8 for ; Wed, 19 Dec 2018 15:19:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730191AbeLSPTz (ORCPT ); Wed, 19 Dec 2018 10:19:55 -0500 Received: from mga14.intel.com ([192.55.52.115]:30409 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730173AbeLSPTw (ORCPT ); Wed, 19 Dec 2018 10:19:52 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Dec 2018 07:19:52 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,373,1539673200"; d="scan'208";a="260746551" Received: from black.fi.intel.com (HELO black.fi.intel.com.) ([10.237.72.28]) by orsmga004.jf.intel.com with ESMTP; 19 Dec 2018 07:19:50 -0800 From: Alexander Shishkin To: Greg Kroah-Hartman Cc: Mathieu Poirier , linux-kernel@vger.kernel.org, Alexander Shishkin , stable@vger.kernel.org Subject: [PATCH v2 3/3] intel_th: msu: Fix an off-by-one in attribute store Date: Wed, 19 Dec 2018 17:19:22 +0200 Message-Id: <20181219151922.44839-4-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181219151922.44839-1-alexander.shishkin@linux.intel.com> References: <20181219151922.44839-1-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The 'nr_pages' attribute of the 'msc' subdevices parses a comma-separated list of window sizes, passed from userspace. However, there is a bug in the string parsing logic wherein it doesn't exclude the comma character from the range of characters as it consumes them. This leads to an out-of-bounds access given a sufficiently long list. For example: > # echo 8,8,8,8 > /sys/bus/intel_th/devices/0-msc0/nr_pages > ================================================================== > BUG: KASAN: slab-out-of-bounds in memchr+0x1e/0x40 > Read of size 1 at addr ffff8803ffcebcd1 by task sh/825 > > CPU: 3 PID: 825 Comm: npktest.sh Tainted: G W 4.20.0-rc1+ > Call Trace: > dump_stack+0x7c/0xc0 > print_address_description+0x6c/0x23c > ? memchr+0x1e/0x40 > kasan_report.cold.5+0x241/0x308 > memchr+0x1e/0x40 > nr_pages_store+0x203/0xd00 [intel_th_msu] Fix this by accounting for the comma character. Signed-off-by: Alexander Shishkin Fixes: ba82664c134ef ("intel_th: Add Memory Storage Unit driver") Cc: stable@vger.kernel.org # v4.4+ --- drivers/hwtracing/intel_th/msu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index d293e55553bd..ba7aaf421f36 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -1423,7 +1423,8 @@ nr_pages_store(struct device *dev, struct device_attribute *attr, if (!end) break; - len -= end - p; + /* consume the number and the following comma, hence +1 */ + len -= end - p + 1; p = end + 1; } while (len); -- 2.19.2