From d67241d43b709af4d13051bb8494892b654aba41 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 27 Jul 2026 13:17:05 -0300 Subject: [PATCH] perf arm-spe: Reject zero nr_cpu in metadata to prevent division by zero arm_spe__alloc_metadata() reads nr_cpu from the auxtrace_info priv array without validation. When a crafted perf.data provides nr_cpu=0, the per_cpu_sz calculation divides by zero: per_cpu_sz = (metadata_size - (hdr_sz * sizeof(u64))) / (*nr_cpu); Reject nr_cpu <= 0 early, before the division. The caller already treats NULL return with metadata_ver != 1 as a parse failure. Fixes: 7842a4b6ff698 ("perf arm-spe: Support metadata version 2") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Reviewed-by: James Clark Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim --- tools/perf/util/arm-spe.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c index 552f063f126e..401aab529309 100644 --- a/tools/perf/util/arm-spe.c +++ b/tools/perf/util/arm-spe.c @@ -1605,6 +1605,10 @@ static u64 **arm_spe__alloc_metadata(struct perf_record_auxtrace_info *info, hdr_sz = ptr[ARM_SPE_HEADER_SIZE]; *nr_cpu = ptr[ARM_SPE_CPUS_NUM]; + /* nr_cpu is used as a divisor below */ + if (*nr_cpu <= 0) + return NULL; + metadata = calloc(*nr_cpu, sizeof(*metadata)); if (!metadata) return NULL;