[PATCH] net: core: sk_buff: zero-fill skb->data in __alloc_skb function

[Phillip Potter]

Zero-fill skb->data in __alloc_skb function of net/core/skbuff.c,
up to start of struct skb_shared_info bytes. Fixes a KMSAN-found
uninit-value bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=abe95dc3e3e9667fc23b8d81f29ecad95c6f106f

Reported-by: syzbot+2e406a9ac75bb71d4b7a@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
---
 net/core/skbuff.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 785daff48030..9ac26cdb5417 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -215,6 +215,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	 * to allow max possible filling before reallocation.
 	 */
 	size = SKB_WITH_OVERHEAD(ksize(data));
+	memset(data, 0, size);
 	prefetchw(data + size);
 
 	/*
-- 
2.30.2