On Tue, 12 Dec 2023 08:44:44 -0500
Steven Rostedt <rost...@goodmis.org> wrote:
> From: "Steven Rostedt (Google)" <rost...@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) <mhira...@kernel.org>
Thanks!
> Signed-off-by: Steven Rostedt (Google) <rost...@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) <mhira...@kernel.org>
