Messages in this thread | | | Date | Wed, 13 Dec 2023 07:47:46 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH] tracing: Add size check when printing trace_marker output |
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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>
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