[PATCH] Fix integer overflow in set_ipsecrequest()

[clingfei]

Hi syzbot,

Please test the following patch.

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master

Thanks.

From db24f0985600db1f88d5d2b7420f0707d67ea05a Mon Sep 17 00:00:00 2001
From: clingfei <clf7...@gmail.com>
Date: Mon, 20 Oct 2025 13:48:54 +0800
Subject: [PATCH] fix integer overflow in set_ipsecrequest()

syzbot reported a kernel BUG in set_ipsecrequest() due to an skb_over_panic.

The mp->new_family and mp->old_family is u16, while set_ipsecrequest receives
family as uint8_t, causing a integer overflow and the later size_req calculation
error, which exceeds the size used in alloc_skb, and ultimately triggered the
kernel bug in skb_put.

Reported-by: syzbot+be97dd...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
Signed-off-by: Cheng Lingfei <clf7...@gmail.com>
---
net/key/af_key.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2ebde0352245..08f4cde01994 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3518,7 +3518,7 @@ static int set_sadb_kmaddress(struct sk_buff *skb, const struct xfrm_kmaddress *

static int set_ipsecrequest(struct sk_buff *skb,
uint8_t proto, uint8_t mode, int level,
- uint32_t reqid, uint8_t family,
+ uint32_t reqid, uint16_t family,
const xfrm_address_t *src, const xfrm_address_t *dst)
{
struct sadb_x_ipsecrequest *rq;
--
2.34.1