From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751659Ab0LYJ5Q (ORCPT ); Sat, 25 Dec 2010 04:57:16 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:63328 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750836Ab0LYJ5O (ORCPT ); Sat, 25 Dec 2010 04:57:14 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=eJ0bgZjO11zLMXQ386h5p9dU2p75VDo0saRxgV+21/7cec76bejVcpc1mV7aYPxGgb NVP7291Ml2+GupAiS/yzXojPzIo/TTCJ4kFsNBjlVwRPC+G58SzQezA6ivMR+phMGbd9 p6YTMoHV80dx4zrHRilxrMqyaYJmqKGQRFVz4= Date: Sat, 25 Dec 2010 11:57:09 +0200 From: "Ahmed S. Darwish" To: Marco Stornelli , LKML Cc: Kyungmin Park , David Woodhouse , Greg KH , Andrew Morton Subject: [PATCH, Bugfix] RAMOOPS: Don't overflow over non-allocated regions Message-ID: <20101225095709.GA1345@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Current code mis-calculates the ramoops header size, leading to an overflow over the next record at best, or over a non-allocated region at worst. Fix that calculation. Signed-off-by: Ahmed S. Darwish -- Shouldn't this be added to -stable too? Happy New Year! drivers/char/ramoops.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c index 73dcb0e..d3d63be 100644 --- a/drivers/char/ramoops.c +++ b/drivers/char/ramoops.c @@ -29,7 +29,6 @@ #include #define RAMOOPS_KERNMSG_HDR "====" -#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval)) #define RECORD_SIZE 4096 @@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, struct ramoops_context, dump); unsigned long s1_start, s2_start; unsigned long l1_cpy, l2_cpy; - int res; - char *buf; + int res, hdr_size; + char *buf, *buf_orig; struct timeval timestamp; /* Only dump oopses if dump_oops is set */ @@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, return; buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE)); + buf_orig = buf; + memset(buf, '\0', RECORD_SIZE); res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR); buf += res; @@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec); buf += res; - l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE)); - l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy); + hdr_size = buf - buf_orig; + l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size)); + l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy); s2_start = l2 - l2_cpy; s1_start = l1 - l1_cpy; -- Darwish http://darwish.07.googlepages.com