Messages in this thread | | | Date | Thu, 15 Apr 2021 16:48:34 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] libperf: xyarray: Add bounds checks to xyarray__entry() |
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Em Thu, Apr 15, 2021 at 04:46:46PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Wed, Apr 14, 2021 at 03:53:36PM -0500, Rob Herring escreveu: > > On Wed, Apr 14, 2021 at 3:25 PM Namhyung Kim <namhyung@kernel.org> wrote: > > > > > > On Thu, Apr 15, 2021 at 4:58 AM Rob Herring <robh@kernel.org> wrote: > > > > > > > > xyarray__entry() is missing any bounds checking yet often the x and y > > > > parameters come from external callers. Add bounds checks and an > > > > unchecked __xyarray__entry(). > > > > > > > > Cc: Peter Zijlstra <peterz@infradead.org> > > > > Cc: Ingo Molnar <mingo@redhat.com> > > > > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > > > > Cc: Mark Rutland <mark.rutland@arm.com> > > > > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> > > > > Cc: Jiri Olsa <jolsa@redhat.com> > > > > Cc: Namhyung Kim <namhyung@kernel.org> > > > > Signed-off-by: Rob Herring <robh@kernel.org> > > > > --- > > > > tools/lib/perf/include/internal/xyarray.h | 9 ++++++++- > > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/tools/lib/perf/include/internal/xyarray.h b/tools/lib/perf/include/internal/xyarray.h > > > > index 51e35d6c8ec4..f0896c00b494 100644 > > > > --- a/tools/lib/perf/include/internal/xyarray.h > > > > +++ b/tools/lib/perf/include/internal/xyarray.h > > > > @@ -18,11 +18,18 @@ struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size); > > > > void xyarray__delete(struct xyarray *xy); > > > > void xyarray__reset(struct xyarray *xy); > > > > > > > > -static inline void *xyarray__entry(struct xyarray *xy, int x, int y) > > > > +static inline void *__xyarray__entry(struct xyarray *xy, int x, int y) > > > > { > > > > return &xy->contents[x * xy->row_size + y * xy->entry_size]; > > > > } > > > > > > > > +static inline void *xyarray__entry(struct xyarray *xy, int x, int y) > > > > +{ > > > > + if (x >= xy->max_x || y >= xy->max_y) > > > > + return NULL; > > > > > > Maybe better to check negatives as well. > > > > max_x and max_y are size_t and unsigned, so x and y will be promoted > > to unsigned and the check will still work. > > Fair enough, applied.
So...:
CC /tmp/build/perf/builtin-script.o In file included from xyarray.c:2: /home/acme/git/perf/tools/lib/perf/include/internal/xyarray.h: In function ‘xyarray__entry’: /home/acme/git/perf/tools/lib/perf/include/internal/xyarray.h:28:8: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare] 28 | if (x >= xy->max_x || y >= xy->max_y) | ^~ /home/acme/git/perf/tools/lib/perf/include/internal/xyarray.h:28:26: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare] 28 | if (x >= xy->max_x || y >= xy->max_y) | ^~ cc1: all warnings being treated as errors
Fedora 33's gcc complains, so I'll cast it to size_t.
- Arnaldo > > > It's probably better to change the args to size_t though. And perhaps > > on xyarray__new(), xyarray__max_y(), and xyarray__max_x() as well.
--
- Arnaldo
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