[PATCH] perf arm-spe: Avoid potential buffer overrun.

[Ian Rogers]

SPE extended headers are >1 byte so ensure the buffer contains at
least this before reading. This issue was detected by fuzzing.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
index f3ac9d40cebf..2e5eff4f8f03 100644
--- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
@@ -210,8 +210,10 @@ static int arm_spe_do_get_packet(const unsigned char *buf, size_t len,
 
 	if ((hdr & SPE_HEADER0_MASK2) == SPE_HEADER0_EXTENDED) {
 		/* 16-bit extended format header */
-		ext_hdr = 1;
+		if (len == 1)
+			return ARM_SPE_BAD_PACKET;
 
+		ext_hdr = 1;
 		hdr = buf[1];
 		if (hdr == SPE_HEADER1_ALIGNMENT)
 			return arm_spe_get_alignment(buf, len, packet);
-- 
2.31.0.208.g409f899ff0-goog