[PATCH RFC 19/20] skbuff: use mempool KASAN hooks

[andrey.konovalov@linux.dev]

From: Andrey Konovalov <andreyknvl@google.com>

Instead of using slab-internal KASAN hooks for poisoning and unpoisoning
cached objects, use the proper mempool KASAN hooks.

Also check the return value of kasan_mempool_poison_object to prevent
double-free and invali-free bugs.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 net/core/skbuff.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 63bb6526399d..bb75b4272992 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -337,7 +337,7 @@ static struct sk_buff *napi_skb_cache_get(void)
 	}
 
 	skb = nc->skb_cache[--nc->skb_count];
-	kasan_unpoison_new_object(skbuff_cache, skb);
+	kasan_mempool_unpoison_object(skb, kmem_cache_size(skbuff_cache));
 
 	return skb;
 }
@@ -1309,13 +1309,15 @@ static void napi_skb_cache_put(struct sk_buff *skb)
 	struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
 	u32 i;
 
-	kasan_poison_new_object(skbuff_cache, skb);
+	if (!kasan_mempool_poison_object(skb))
+		return;
+
 	nc->skb_cache[nc->skb_count++] = skb;
 
 	if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
 		for (i = NAPI_SKB_CACHE_HALF; i < NAPI_SKB_CACHE_SIZE; i++)
-			kasan_unpoison_new_object(skbuff_cache,
-						  nc->skb_cache[i]);
+			kasan_mempool_unpoison_object(nc->skb_cache[i],
+						kmem_cache_size(skbuff_cache));
 
 		kmem_cache_free_bulk(skbuff_cache, NAPI_SKB_CACHE_HALF,
 				     nc->skb_cache + NAPI_SKB_CACHE_HALF);
-- 
2.25.1