perf header: Sanity check HEADER_BPF_PROG_INFO

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

- Upper bound on BPF program count (max 131072)
- Upper bound on per-program data_len (max 256MB)

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>

Author: acmel

tools/perf/util/header.c

@@ -63,6 +63,8 @@
 #include <event-parse.h>
 #endif
 
+#define MAX_BPF_DATA_LEN	(256 * 1024 * 1024)
+#define MAX_BPF_PROGS		131072
 #define MAX_CACHE_ENTRIES	32768
 #define MAX_GROUP_DESC		32768
 #define MAX_NUMA_NODES		4096
@@ -3525,6 +3527,18 @@ static int process_bpf_prog_info(struct feat_fd *ff __maybe_unused, void *data _
 	if (do_read_u32(ff, &count))
 		return -1;
 
+	if (count > MAX_BPF_PROGS) {
+		pr_err("Invalid HEADER_BPF_PROG_INFO: count (%u) > %u\n",
+		       count, MAX_BPF_PROGS);
+		return -1;
+	}
+
+	if (ff->size < sizeof(u32) + count * (2 * sizeof(u32) + sizeof(u64))) {
+		pr_err("Invalid HEADER_BPF_PROG_INFO: section too small (%zu) for %u entries\n",
+		       ff->size, count);
+		return -1;
+	}
+
 	down_write(&env->bpf_progs.lock);
 
 	for (i = 0; i < count; ++i) {
@@ -3542,6 +3556,12 @@ static int process_bpf_prog_info(struct feat_fd *ff __maybe_unused, void *data _
 			goto out;
 		}
 
+		if (data_len > MAX_BPF_DATA_LEN) {
+			pr_warning("Invalid HEADER_BPF_PROG_INFO: data_len (%u) too large\n",
+				   data_len);
+			goto out;
+		}
+
 		info_linear = malloc(sizeof(struct perf_bpil) +
 				     data_len);
 		if (!info_linear)