From: Xin Long lucien.xin@gmail.com
commit f6a23d85d078c2ffde79c66ca81d0a1dde451649 upstream.
This patch is to fix a crash:
[ ] kasan: GPF could be caused by NULL-ptr deref or user memory access [ ] general protection fault: 0000 [#1] SMP KASAN PTI [ ] RIP: 0010:ipv6_local_error+0xac/0x7a0 [ ] Call Trace: [ ] xfrm6_local_error+0x1eb/0x300 [ ] xfrm_local_error+0x95/0x130 [ ] __xfrm6_output+0x65f/0xb50 [ ] xfrm6_output+0x106/0x46f [ ] udp_tunnel6_xmit_skb+0x618/0xbf0 [ip6_udp_tunnel] [ ] vxlan_xmit_one+0xbc6/0x2c60 [vxlan] [ ] vxlan_xmit+0x6a0/0x4276 [vxlan] [ ] dev_hard_start_xmit+0x165/0x820 [ ] __dev_queue_xmit+0x1ff0/0x2b90 [ ] ip_finish_output2+0xd3e/0x1480 [ ] ip_do_fragment+0x182d/0x2210 [ ] ip_output+0x1d0/0x510 [ ] ip_send_skb+0x37/0xa0 [ ] raw_sendmsg+0x1b4c/0x2b80 [ ] sock_sendmsg+0xc0/0x110
This occurred when sending a v4 skb over vxlan6 over ipsec, in which case skb->protocol == htons(ETH_P_IPV6) while skb->sk->sk_family == AF_INET in xfrm_local_error(). Then it will go to xfrm6_local_error() where it tries to get ipv6 info from a ipv4 sk.
This issue was actually fixed by Commit 628e341f319f ("xfrm: make local error reporting more robust"), but brought back by Commit 844d48746e4b ("xfrm: choose protocol family by skb protocol").
So to fix it, we should call xfrm6_local_error() only when skb->protocol is htons(ETH_P_IPV6) and skb->sk->sk_family is AF_INET6.
Fixes: 844d48746e4b ("xfrm: choose protocol family by skb protocol") Reported-by: Xiumei Mu xmu@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/xfrm/xfrm_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -642,7 +642,8 @@ void xfrm_local_error(struct sk_buff *sk
if (skb->protocol == htons(ETH_P_IP)) proto = AF_INET; - else if (skb->protocol == htons(ETH_P_IPV6)) + else if (skb->protocol == htons(ETH_P_IPV6) && + skb->sk->sk_family == AF_INET6) proto = AF_INET6; else return;