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* [PATCH] perf arm-spe: Avoid potential buffer overrun.
@ 2021-04-07 15:39 Ian Rogers
  2021-04-07 19:24 ` Arnaldo Carvalho de Melo
  0 siblings, 1 reply; 2+ messages in thread
From: Ian Rogers @ 2021-04-07 15:39 UTC (permalink / raw)
  To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
	Leo Yan, Andre Przywara, Will Deacon, Dave Martin, linux-kernel
  Cc: Stephane Eranian, 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@google.com>
---
 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


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2021-04-07 15:39 [PATCH] perf arm-spe: Avoid potential buffer overrun Ian Rogers
2021-04-07 19:24 ` Arnaldo Carvalho de Melo

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