1 files changed, 51 insertions, 0 deletions
diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
new file mode 100644
index 000000000000..8a319fc16dab
--- /dev/null
+++ b/mm/kasan/report_tags.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2020 Google, Inc.
+ */
+
+#include "kasan.h"
+#include "../slab.h"
+
+const char *kasan_get_bug_type(struct kasan_access_info *info)
+{
+#ifdef CONFIG_KASAN_TAGS_IDENTIFY
+	struct kasan_alloc_meta *alloc_meta;
+	struct kmem_cache *cache;
+	struct page *page;
+	const void *addr;
+	void *object;
+	u8 tag;
+	int i;
+
+	tag = get_tag(info->access_addr);
+	addr = kasan_reset_tag(info->access_addr);
+	page = kasan_addr_to_page(addr);
+	if (page && PageSlab(page)) {
+		cache = page->slab_cache;
+		object = nearest_obj(cache, page, (void *)addr);
+		alloc_meta = kasan_get_alloc_meta(cache, object);
+
+		if (alloc_meta) {
+			for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
+				if (alloc_meta->free_pointer_tag[i] == tag)
+					return "use-after-free";
+			}
+		}
+		return "out-of-bounds";
+	}
+#endif
+
+	/*
+	 * If access_size is a negative number, then it has reason to be
+	 * defined as out-of-bounds bug type.
+	 *
+	 * Casting negative numbers to size_t would indeed turn up as
+	 * a large size_t and its value will be larger than ULONG_MAX/2,
+	 * so that this can qualify as out-of-bounds.
+	 */
+	if (info->access_addr + info->access_size < info->access_addr)
+		return "out-of-bounds";
+
+	return "invalid-access";
+}