lkml.org 
[lkml]   [2023]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] tracing: Add size check when printing trace_marker output
On Tue, 12 Dec 2023 08:44:44 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> 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) <mhiramat@kernel.org>

Thanks!

> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> 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) <mhiramat@kernel.org>

\
 
 \ /
  Last update: 2023-12-12 23:48    [W:2.400 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site