[PATCH 3/5] perf intel-pt: Fix off-by-one in auxtrace_info minimum size check

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

min_sz is set to sizeof(u64) * INTEL_PT_PER_CPU_MMAPS, but the code
accesses auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS], which requires
at least INTEL_PT_PER_CPU_MMAPS + 1 elements.  A file with exactly
min_sz bytes of priv data passes the size check but the access reads
one u64 past the validated region.

Use (INTEL_PT_PER_CPU_MMAPS + 1) to ensure the highest accessed index
is within bounds.

Fixes: 90e457f7be087005 ("perf tools: Add Intel PT support")
Reported-by: sashiko-bot <sashiko-bot@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/intel-pt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index d83439c8c7b0ab0f..9d6628169fd95772 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -4432,7 +4432,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
 				   struct perf_session *session)
 {
 	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
-	size_t min_sz = sizeof(u64) * INTEL_PT_PER_CPU_MMAPS;
+	size_t min_sz = sizeof(u64) * (INTEL_PT_PER_CPU_MMAPS + 1);
 	struct intel_pt *pt;
 	void *info_end;
 	__u64 *info;
-- 
2.55.0