[PATCH 06/13] perf header: Sanity check HEADER_MEM_TOPOLOGY

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Add validation to process_mem_topology() to harden against malformed
perf.data files:

- Upper bound check on nr_nodes (reuses MAX_NUMA_NODES, 4096)
- Minimum section size check before allocating

This is particularly important here since nr is u64, making unbounded
values especially dangerous.

Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude Code:claude-opus-4-6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/header.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 2c6f7c96e2dccaf1..45f533fbb8fdc3c6 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3306,6 +3306,18 @@ static int process_mem_topology(struct feat_fd *ff,
 	if (do_read_u64(ff, &nr))
 		return -1;
 
+	if (nr > MAX_NUMA_NODES) {
+		pr_err("Invalid HEADER_MEM_TOPOLOGY: nr_nodes (%llu) > %u\n",
+		       (unsigned long long)nr, MAX_NUMA_NODES);
+		return -1;
+	}
+
+	if (ff->size < 3 * sizeof(u64) + nr * 2 * sizeof(u64)) {
+		pr_err("Invalid HEADER_MEM_TOPOLOGY: section too small (%zu) for %llu nodes\n",
+		       ff->size, (unsigned long long)nr);
+		return -1;
+	}
+
 	nodes = calloc(nr, sizeof(*nodes));
 	if (!nodes)
 		return -1;
-- 
2.53.0