arm64: perf: fix array out of bounds access in armpmu_map_hw_event()

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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 9ba33c4..2012646 100644 (file)
--- 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;
 }