[PATCH v13 27/32] perf kmem: Add bounds checks to tracepoint read values

[Ian Rogers <irogers@google.com>]

Avoid out-of-bound memory accesses by bound checking order and
migrate_type when coming from page_alloc_event and page_free_event.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-kmem.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index daf2272c7337..33585e353efe 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -826,6 +826,16 @@ static int evsel__process_page_alloc_event(struct perf_sample *sample)
 		.migrate_type = migrate_type,
 	};
 
+	if (order >= MAX_PAGE_ORDER) {
+		pr_debug("Out-of-bounds order %u\n", order);
+		return -1;
+	}
+
+	if (migrate_type >= MAX_MIGRATE_TYPES) {
+		pr_debug("Out-of-bounds migratetype %u\n", migrate_type);
+		return -1;
+	}
+
 	if (use_pfn)
 		page = perf_sample__intval(sample, "pfn");
 	else
@@ -892,6 +902,11 @@ static int evsel__process_page_free_event(struct perf_sample *sample)
 		.order = order,
 	};
 
+	if (order >= MAX_PAGE_ORDER) {
+		pr_debug("Out-of-bounds order %u\n", order);
+		return -1;
+	}
+
 	if (use_pfn)
 		page = perf_sample__intval(sample, "pfn");
 	else
-- 
2.54.0.563.g4f69b47b94-goog