From: Eyal Birger eyal.birger@gmail.com

stable inclusion from linux-4.19.187 commit b318f319b0c81965adaba0997cdddd9e280270d5

--------------------------------

[ Upstream commit 8fc0e3b6a8666d656923d214e4dc791e9a17164a ]

Frag needed should only be sent if the header enables DF.

This fix allows packets larger than MTU to pass the xfrm interface and be fragmented after encapsulation, aligning behavior with non-interface xfrm.

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces") Signed-off-by: Eyal Birger eyal.birger@gmail.com Reviewed-by: Sabrina Dubroca sd@queasysnail.net Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/xfrm/xfrm_interface.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c index 2e3fc48ced424..9dd43319b2c06 100644 --- a/net/xfrm/xfrm_interface.c +++ b/net/xfrm/xfrm_interface.c @@ -302,6 +302,8 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)

icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); } else { + if (!(ip_hdr(skb)->frag_off & htons(IP_DF))) + goto xmit; icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); } @@ -310,6 +312,7 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) return -EMSGSIZE; }

+xmit: xfrmi_scrub_packet(skb, !net_eq(xi->net, dev_net(dev))); skb_dst_set(skb, dst); skb->dev = tdev;