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

[Arnaldo Carvalho de Melo]

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@xxxxxxxxxx>
> > ---
> >  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@xxxxxxxxxx>

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

- arnaldo