Messages in this thread | | | From | Rob Herring <> | Date | Wed, 14 Apr 2021 15:53:36 -0500 | Subject | Re: [PATCH] libperf: xyarray: Add bounds checks to xyarray__entry() |
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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.
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.
Rob
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