[PATCH] libperf: xyarray: Add bounds checks to xyarray__entry()

[Rob Herring]

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@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
 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;
+	return __xyarray__entry(xy, x, y);
+}
+
 static inline int xyarray__max_y(struct xyarray *xy)
 {
 	return xy->max_y;
-- 
2.27.0