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From:   andrey.konovalov@linux.dev
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        Evgenii Stepanov <eugenis@google.com>,
        Oscar Salvador <osalvador@suse.de>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v4 19/22] kasan: check object_size in kasan_complete_mode_report_info
Date:   Mon, 20 Nov 2023 18:47:17 +0100
Message-Id: <68c6948175aadd7e7e7deea61725103d64a4528f.1700502145.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

Check the object size when looking up entries in the stack ring.

If the size of the object for which a report is being printed does not
match the size of the object for which a stack trace has been saved in
the stack ring, the saved stack trace is irrelevant.

Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

---

Changes v2->v3:
- Added missing "../slab.h" include for accessing a kmem_cache field.

Changes v1->v2:
- This is a new patch.
---
 mm/kasan/report_tags.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
index 78abdcde5da9..55154743f915 100644
--- a/mm/kasan/report_tags.c
+++ b/mm/kasan/report_tags.c
@@ -7,6 +7,7 @@
 #include <linux/atomic.h>
 
 #include "kasan.h"
+#include "../slab.h"
 
 extern struct kasan_stack_ring stack_ring;
 
@@ -58,7 +59,8 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info)
 		entry = &stack_ring.entries[i % stack_ring.size];
 
 		if (kasan_reset_tag(entry->ptr) != info->object ||
-		    get_tag(entry->ptr) != get_tag(info->access_addr))
+		    get_tag(entry->ptr) != get_tag(info->access_addr) ||
+		    info->cache->object_size != entry->size)
 			continue;
 
 		if (entry->is_free) {
-- 
2.25.1