[PATCH 46/58] arm64: perf: fix array out of bounds access in armpmu_map_hw_event()

[Kamal Mostafa]

3.8.13.8 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@xxxxxxx>

commit 868f6fea8fa63f09acbfa93256d0d2abdcabff79 upstream.

This is a port of d9f966357b14 ("ARM: 7810/1: perf: Fix array out of
bounds access in armpmu_map_hw_event()") to arm64, which fixes an oops
in the arm64 perf backend found as a result of Vince's fuzzing tool.

Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 arch/arm64/kernel/perf_event.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 0256b68..8a724a1 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -107,7 +107,12 @@ armpmu_map_cache_event(const unsigned (*cache_map)
 static int
 armpmu_map_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
 {
-	int mapping = (*event_map)[config];
+	int mapping;
+
+	if (config >= PERF_COUNT_HW_MAX)
+		return -EINVAL;
+
+	mapping = (*event_map)[config];
 	return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
 }
 
-- 
1.8.1.2

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