From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757669AbaKTPaZ (ORCPT ); Thu, 20 Nov 2014 10:30:25 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.226]:7721 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757298AbaKTP1T (ORCPT ); Thu, 20 Nov 2014 10:27:19 -0500 Message-Id: <20141120152716.901899133@goodmis.org> User-Agent: quilt/0.61-1 Date: Thu, 20 Nov 2014 10:21:28 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Jiri Kosina , Petr Mladek Subject: [for-next][PATCH 08/15] tracing: Add paranoid size check in trace_printk_seq() References: <20141120152120.168868031@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0008-tracing-Add-paranoid-size-check-in-trace_printk_seq.patch X-RR-Connecting-IP: 107.14.168.130:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (Red Hat)" To be really paranoid about writing out of bound data in trace_printk_seq(), add another check of len compared to size. Link: http://lkml.kernel.org/r/20141119144004.GB2332@dhcp128.suse.cz Suggested-by: Petr Mladek Reviewed-by: Petr Mladek Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9023446b2c2b..26facec4625e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6656,6 +6656,14 @@ trace_printk_seq(struct trace_seq *s) if (s->seq.len >= TRACE_MAX_PRINT) s->seq.len = TRACE_MAX_PRINT; + /* + * More paranoid code. Although the buffer size is set to + * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just + * an extra layer of protection. + */ + if (WARN_ON_ONCE(s->seq.len >= s->seq.size)) + s->seq.len = s->seq.size - 1; + /* should be zero ended, but we are paranoid. */ s->buffer[s->seq.len] = 0; -- 2.1.1