Hi syzbot, Please test the following patch. #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master Thanks, Shaurya Rane From 123c5ac9ba261681b58a6217409c94722fde4249 Mon Sep 17 00:00:00 2001 From: Shaurya Rane Date: Sun, 19 Oct 2025 23:18:30 +0530 Subject: [PATCH] net: key: Validate address family in set_ipsecrequest() syzbot reported a kernel BUG in set_ipsecrequest() due to an skb_over_panic when processing XFRM_MSG_MIGRATE messages. The root cause is that set_ipsecrequest() does not validate the address family parameter before using it to calculate buffer sizes. When an unsupported family value (such as 0) is passed, pfkey_sockaddr_len() returns 0, leading to incorrect size calculations. In pfkey_send_migrate(), the buffer size is calculated based on pfkey_sockaddr_pair_size(), which uses pfkey_sockaddr_len(). When family=0, this returns 0, so only sizeof(struct sadb_x_ipsecrequest) (16 bytes) is allocated per entry. However, set_ipsecrequest() is called multiple times in a loop (once for old_family, once for new_family, for each migration bundle), repeatedly calling skb_put_zero() with 16 bytes each time. This causes the tail pointer to exceed the end pointer of the skb, triggering skb_over_panic: tail: 0x188 (392 bytes) end: 0x180 (384 bytes) Fix this by validating that pfkey_sockaddr_len() returns a non-zero value before proceeding with buffer operations. This ensures proper size calculations and prevents buffer overflow. Checking socklen instead of just family==0 provides comprehensive validation for all unsupported address families. Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4 Fixes: 08de61beab8a ("[PFKEYV2]: Extension for dynamic update of endpoint address(es)") Signed-off-by: Shaurya Rane --- net/key/af_key.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/key/af_key.c b/net/key/af_key.c index 2ebde0352245..713344c594d4 100644 --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -3526,6 +3526,10 @@ static int set_ipsecrequest(struct sk_buff *skb, int socklen = pfkey_sockaddr_len(family); int size_req; + /* Reject invalid/unsupported address families */ + if (!socklen) + return -EINVAL; + size_req = sizeof(struct sadb_x_ipsecrequest) + pfkey_sockaddr_pair_size(family); -- 2.34.1