From mboxrd@z Thu Jan 1 00:00:00 1970 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 514321798F for ; Tue, 12 Dec 2023 22:47:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UQoT7kHu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40E35C433C7; Tue, 12 Dec 2023 22:47:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702421270; bh=fTzQszjJZI1SU83F2DPicXFge7TTPi0j6QJoBbVl1TI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=UQoT7kHuV6vYeIp2c9J97rMAU/aseRE7+I8zj2u86LxOKPQN1l4BJR9RdO27xHGKh bAMyPCc/73mlXUi9IKA+ZnB9OzETYfDcVhTlammymBEyJHwM15dEhUzojsa5nolcjr yWtWXwtFNhy5mzf7KKrLDLZ2KkOWER5le/4pWK0RCxipo+VHPi0UGCKgcp0wyHR1uo xbNi7X8Ugo4Opw8qTpYwfLVUrUslrclsAr0xLXyNOWR05u+TO9w5++hx59S5vO8Y2T +eFu5FGg/fyWaT4J5LYjd0FpZ72mODhtnIubXfkRVjFLSnnZfwXpH9bg/jpNp9jinI yPVerbXa1ysiw== Date: Wed, 13 Dec 2023 07:47:46 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: LKML , Linux Trace Kernel , Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers Subject: Re: [PATCH] tracing: Add size check when printing trace_marker output Message-Id: <20231213074746.cd2dbd703bd19fe791c5d44a@kernel.org> In-Reply-To: <20231212084444.4619b8ce@gandalf.local.home> References: <20231212084444.4619b8ce@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 12 Dec 2023 08:44:44 -0500 Steven Rostedt wrote: > 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 = iter->ent_size - offsetof(struct print_entry, buf); > > trace_seq_printf(s, ": %*s", max, field->buf); > This looks good to me. Reviewed-by: Masami Hiramatsu (Google) Thanks! > 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..e11fb8996286 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 trace_iterator *iter, > { > struct print_entry *field; > struct trace_seq *s = &iter->seq; > + int max = iter->ent_size - offsetof(struct print_entry, buf); > > trace_assign_type(field, iter->ent); > > seq_print_ip_sym(s, field->ip, flags); > - trace_seq_printf(s, ": %s", field->buf); > + trace_seq_printf(s, ": %*s", max, field->buf); > > return trace_handle_return(s); > } > @@ -1600,10 +1601,11 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags, > struct trace_event *event) > { > struct print_entry *field; > + int max = iter->ent_size - offsetof(struct print_entry, buf); > > trace_assign_type(field, iter->ent); > > - trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf); > + trace_seq_printf(&iter->seq, "# %lx %*s", field->ip, max, field->buf); > > return trace_handle_return(&iter->seq); > } > -- > 2.42.0 > -- Masami Hiramatsu (Google)