[PATCH 04/13] perf header: Sanity check HEADER_CPU_TOPOLOGY

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

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

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

- Verify nr_cpus_avail was initialized (HEADER_NRCPUS processed first)
- Bounds check sibling counts (cores, threads, dies) against nr_cpus_avail
- Fix two bare 'return -1' that leaked env->cpu by using 'goto free_cpu'

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 | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 2d23dbc666b676be..a7df8ed9a69e9231 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2859,6 +2859,11 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 	int cpu_nr = env->nr_cpus_avail;
 	u64 size = 0;
 
+	if (cpu_nr == 0) {
+		pr_err("Invalid HEADER_CPU_TOPOLOGY: missing HEADER_NRCPUS\n");
+		return -1;
+	}
+
 	env->cpu = calloc(cpu_nr, sizeof(*env->cpu));
 	if (!env->cpu)
 		return -1;
@@ -2866,6 +2871,12 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 	if (do_read_u32(ff, &nr))
 		goto free_cpu;
 
+	if (nr > (u32)cpu_nr) {
+		pr_err("Invalid HEADER_CPU_TOPOLOGY: nr_sibling_cores (%u) > nr_cpus_avail (%d)\n",
+		       nr, cpu_nr);
+		goto free_cpu;
+	}
+
 	env->nr_sibling_cores = nr;
 	size += sizeof(u32);
 	if (strbuf_init(&sb, 128) < 0)
@@ -2885,7 +2896,13 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 	env->sibling_cores = strbuf_detach(&sb, NULL);
 
 	if (do_read_u32(ff, &nr))
-		return -1;
+		goto free_cpu;
+
+	if (nr > (u32)cpu_nr) {
+		pr_err("Invalid HEADER_CPU_TOPOLOGY: nr_sibling_threads (%u) > nr_cpus_avail (%d)\n",
+		       nr, cpu_nr);
+		goto free_cpu;
+	}
 
 	env->nr_sibling_threads = nr;
 	size += sizeof(u32);
@@ -2934,7 +2951,13 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 		return 0;
 
 	if (do_read_u32(ff, &nr))
-		return -1;
+		goto free_cpu;
+
+	if (nr > (u32)cpu_nr) {
+		pr_err("Invalid HEADER_CPU_TOPOLOGY: nr_sibling_dies (%u) > nr_cpus_avail (%d)\n",
+		       nr, cpu_nr);
+		goto free_cpu;
+	}
 
 	env->nr_sibling_dies = nr;
 	size += sizeof(u32);
-- 
2.53.0