perf header: Sanity check HEADER_PMU_MAPPINGS

Add upper bound check on pmu_num in process_pmu_mappings() to harden
against malformed perf.data files (max 4096).

Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude Code:claude-opus-4-6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 2eb909672f826ca48bcaf5f0a667bea316b87ecf..77035d9b138cb3cd3fbc7a79797dd1a2abbd71c8 100644 (file)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -64,6 +64,7 @@
 #endif
 
 #define MAX_NUMA_NODES         4096
+#define MAX_PMU_MAPPINGS       4096
 #define MAX_SCHED_DOMAINS      64
 
 /*
@@ -3069,6 +3070,18 @@ static int process_pmu_mappings(struct feat_fd *ff, void *data __maybe_unused)
                return 0;
        }
 
+       if (pmu_num > MAX_PMU_MAPPINGS) {
+               pr_err("Invalid HEADER_PMU_MAPPINGS: pmu_num (%u) > %u\n",
+                      pmu_num, MAX_PMU_MAPPINGS);
+               return -1;
+       }
+
+       if (ff->size < sizeof(u32) + pmu_num * 2 * sizeof(u32)) {
+               pr_err("Invalid HEADER_PMU_MAPPINGS: section too small (%zu) for %u PMUs\n",
+                      ff->size, pmu_num);
+               return -1;
+       }
+
        env->nr_pmu_mappings = pmu_num;
        if (strbuf_init(&sb, 128) < 0)
                return -1;