2023-08-30 18:34:33

by Namhyung Kim

Subject: Re: [PATCH v1] perf pmu: Avoid uninitialized use of alias->str

Hi Ian,

On Tue, Aug 29, 2023 at 5:05 PM Ian Rogers <[email protected]> wrote:
>
> alias is allocated with malloc allowing uninitialized memory to be
> accessed. The initialization of str was moved late after it could have
> been updated by a JSON event, however, this create a potential for an
> uninitialized use. Fix this by assigning str to NULL early. Testing on
> ARM (Raspberry Pi) showed a memory leak in the same code so add a
> zfree.
>
> Fixes: f63a536f03a2 ("perf pmu: Merge JSON events with sysfs at load time")
> Signed-off-by: Ian Rogers <[email protected]>

Acked-by: Namhyung Kim <[email protected]>

Thanks,
Namhyung


> ---
> tools/perf/util/pmu.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index cde33e01959a..b3f8f3f1e900 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -532,6 +532,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
> if (!alias)
> return -ENOMEM;
>
> + alias->str = NULL;
> INIT_LIST_HEAD(&alias->terms);
> alias->scale = 1.0;
> alias->unit[0] = '\0';
> @@ -593,6 +594,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
> ret += scnprintf(newval + ret, sizeof(newval) - ret,
> "%s=%s", term->config, term->val.str);
> }
> + zfree(&alias->str);
> alias->str = strdup(newval);
> if (!pe)
> pmu->sysfs_aliases++;
> --
> 2.42.0.rc2.253.gd59a3bf2b4-goog
>

2023-08-30 18:53:14

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH v1] perf pmu: Avoid uninitialized use of alias->str

Em Tue, Aug 29, 2023 at 07:23:58PM -0700, Namhyung Kim escreveu:
> Hi Ian,
>
> On Tue, Aug 29, 2023 at 5:05 PM Ian Rogers <[email protected]> wrote:
> >
> > alias is allocated with malloc allowing uninitialized memory to be
> > accessed. The initialization of str was moved late after it could have
> > been updated by a JSON event, however, this create a potential for an
> > uninitialized use. Fix this by assigning str to NULL early. Testing on
> > ARM (Raspberry Pi) showed a memory leak in the same code so add a
> > zfree.
> >
> > Fixes: f63a536f03a2 ("perf pmu: Merge JSON events with sysfs at load time")
> > Signed-off-by: Ian Rogers <[email protected]>
>
> Acked-by: Namhyung Kim <[email protected]>

Thanks, applied.

- Arnaldo

> Thanks,
> Namhyung
>
>
> > ---
> > tools/perf/util/pmu.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index cde33e01959a..b3f8f3f1e900 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -532,6 +532,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
> > if (!alias)
> > return -ENOMEM;
> >
> > + alias->str = NULL;
> > INIT_LIST_HEAD(&alias->terms);
> > alias->scale = 1.0;
> > alias->unit[0] = '\0';
> > @@ -593,6 +594,7 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
> > ret += scnprintf(newval + ret, sizeof(newval) - ret,
> > "%s=%s", term->config, term->val.str);
> > }
> > + zfree(&alias->str);
> > alias->str = strdup(newval);
> > if (!pe)
> > pmu->sysfs_aliases++;
> > --
> > 2.42.0.rc2.253.gd59a3bf2b4-goog
> >

--

- Arnaldo