From nobody Thu Dec 18 14:48:19 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CA72C4332F for ; Wed, 13 Dec 2023 03:11:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378393AbjLMDLX (ORCPT ); Tue, 12 Dec 2023 22:11:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230510AbjLMDLW (ORCPT ); Tue, 12 Dec 2023 22:11:22 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E295DB2 for ; Tue, 12 Dec 2023 19:11:28 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED057C433C7; Wed, 13 Dec 2023 03:11:27 +0000 (UTC) Date: Tue, 12 Dec 2023 22:12:11 -0500 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers Subject: [PATCH v2] tracing: Add size check when printing trace_marker output Message-ID: <20231212221211.79d6d09b@gandalf.local.home> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" If for some reason the trace_marker write does not have a nul byte for the string, it will overflow the print: trace_seq_printf(s, ": %s", field->buf); The field->buf could be missing the nul byte. To prevent overflow, add the max size that the buf can be by using the event size and the field location. int max =3D iter->ent_size - offsetof(struct print_entry, buf); trace_seq_printf(s, ": %*.s", max, field->buf); Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- Changes since v1: https://lore.kernel.org/linux-trace-kernel/20231212084444= .4619b8ce@gandalf.local.home - Use "%.*s" and not "%*s" otherwise it right aligns the output. [ Masami, I kept your review by. ] kernel/trace/trace_output.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index d8b302d01083..3e7fa44dc2b2 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -1587,11 +1587,12 @@ static enum print_line_t trace_print_print(struct t= race_iterator *iter, { struct print_entry *field; struct trace_seq *s =3D &iter->seq; + int max =3D iter->ent_size - offsetof(struct print_entry, buf); =20 trace_assign_type(field, iter->ent); =20 seq_print_ip_sym(s, field->ip, flags); - trace_seq_printf(s, ": %s", field->buf); + trace_seq_printf(s, ": %.*s", max, field->buf); =20 return trace_handle_return(s); } @@ -1600,10 +1601,11 @@ static enum print_line_t trace_print_raw(struct tra= ce_iterator *iter, int flags, struct trace_event *event) { struct print_entry *field; + int max =3D iter->ent_size - offsetof(struct print_entry, buf); =20 trace_assign_type(field, iter->ent); =20 - trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf); + trace_seq_printf(&iter->seq, "# %lx %.*s", field->ip, max, field->buf); =20 return trace_handle_return(&iter->seq); } --=20 2.42.0