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

[Ian Rogers]

Thanks Arnaldo, this patch shouldn't be added. It was replaced with
the longer v2 patch that addressed the memory issues properly. That
was followed by a number of improved versions.

Ian

On Mon, Nov 11, 2019 at 6:25 AM Arnaldo Carvalho de Melo
<arnaldo.melo@xxxxxxxxx> wrote:
>
> 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