From nobody Sat Dec 27 20:37:51 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82D38171DA for ; Sat, 16 Dec 2023 04:21:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 424E9C43215; Sat, 16 Dec 2023 04:21:53 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rEMCK-00000002yEF-0iz1; Fri, 15 Dec 2023 23:22:44 -0500 Message-ID: <20231216042243.959035900@goodmis.org> User-Agent: quilt/0.67 Date: Fri, 15 Dec 2023 23:22:22 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [for-linus][PATCH 08/15] tracing: Add size check when printing trace_marker output References: <20231216042214.905262999@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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); Link: https://lore.kernel.org/linux-trace-kernel/20231212084444.4619b8ce@ga= ndalf.local.home Cc: Mark Rutland Cc: Mathieu Desnoyers Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- 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