Re: [PATCH] perf tools: avoid reading out of scope array

Arnaldo Carvalho de Melo
2019-11-11T14:25:16Z

Em Wed, Oct 23, 2019 at 10:29:12AM +0200, Jiri Olsa escreveu:
> On Thu, Oct 17, 2019 at 10:05:31AM -0700, Ian Rogers wrote:
> > Modify tracepoint name into 2 sys components and assemble at use. This
> > avoids the sys_name array being out of scope at the point of use.
> > Bug caught with LLVM's address sanitizer with fuzz generated input of
> > ":cs\1" to parse_events.
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> > tools/perf/util/parse-events.y | 36 +++++++++++++++++++++++-----------
> > 1 file changed, 25 insertions(+), 11 deletions(-)
> >
> > diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
> > index 48126ae4cd13..28be39a703c9 100644
> > --- a/tools/perf/util/parse-events.y
> > +++ b/tools/perf/util/parse-events.y
> > @@ -104,7 +104,8 @@ static void inc_group_count(struct list_head *list,
> > struct list_head *head;
> > struct parse_events_term *term;
> > struct tracepoint_name {
> > - char *sys;
> > + char *sys1;
> > + char *sys2;
> > char *event;
> > } tracepoint_name;
> > struct parse_events_array array;
> > @@ -425,9 +426,19 @@ tracepoint_name opt_event_config
> > if (error)
> > error->idx = @1.first_column;
> >
> > - if (parse_events_add_tracepoint(list, &parse_state->idx, $1.sys, $1.event,
> > - error, $2))
> > - return -1;
> > + if ($1.sys2) {
> > + char sys_name[128];
> > + snprintf(&sys_name, sizeof(sys_name), "%s-%s",
> > + $1.sys1, $1.sys2);
> > + if (parse_events_add_tracepoint(list, &parse_state->idx,
> > + sys_name, $1.event,
> > + error, $2))
> > + return -1;
> > + } else
> > + if (parse_events_add_tracepoint(list, &parse_state->idx,
> > + $1.sys1, $1.event,
> > + error, $2))
> > + return -1;
>
> nice catch, please enclose all multiline condition legs with {}
>
> other than that
>
> Acked-by: Jiri Olsa <jolsa@kernel.org>

Ian, this one isn't applying to my perf/core branch, can you please
address Jiri's comment and resubmit?

- arnaldo