In the output path, xfrm_dev_offload_ok and xfrm_get_inner_ipproto need to determine the protocol family of the inner packet (skb) before it gets encapsulated. In xfrm_dev_offload_ok, the code checked x->inner_mode.family. This is unreliable because, for states handling both IPv4 and IPv6, the relevant inner family could be either x->inner_mode.family or x->inner_mode_iaf.family. Checking only the former can lead to a mismatch with the actual packet being processed. In xfrm_get_inner_ipproto, the code checked x->outer_mode.family. This is also incorrect for tunnel mode, as the inner packet's family can be different from the outer header's family. At both of these call sites, the skb variable holds the original inner packet. The most direct and reliable source of truth for its protocol family is its destination entry. This patch fixes the issue by using skb_dst(skb)->ops->family to ensure protocol-specific headers are only accessed for the correct packet type. Fixes: 91d8a53db219 ("xfrm: fix offloading of cross-family tunnels") Fixes: 45a98ef4922d ("net/xfrm: IPsec tunnel mode fix inner_ipproto setting in sec_path") Signed-off-by: Jianbo Liu Reviewed-by: Cosmin Ratiu --- V2: - Change subject prefix, and send to "ipsec". - Update commit msg. - Add Fixes tag. net/xfrm/xfrm_device.c | 2 +- net/xfrm/xfrm_output.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c index 44b9de6e4e77..52ae0e034d29 100644 --- a/net/xfrm/xfrm_device.c +++ b/net/xfrm/xfrm_device.c @@ -438,7 +438,7 @@ bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x) check_tunnel_size = x->xso.type == XFRM_DEV_OFFLOAD_PACKET && x->props.mode == XFRM_MODE_TUNNEL; - switch (x->inner_mode.family) { + switch (skb_dst(skb)->ops->family) { case AF_INET: /* Check for IPv4 options */ if (ip_hdr(skb)->ihl != 5) diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c index 9077730ff7d0..a98b5bf55ac3 100644 --- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -698,7 +698,7 @@ static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x) return; if (x->outer_mode.encap == XFRM_MODE_TUNNEL) { - switch (x->outer_mode.family) { + switch (skb_dst(skb)->ops->family) { case AF_INET: xo->inner_ipproto = ip_hdr(skb)->protocol; break; -- 2.49.0 The GSO segmentation functions for ESP tunnel mode (xfrm4_tunnel_gso_segment and xfrm6_tunnel_gso_segment) were determining the inner packet's L2 protocol type by checking the static x->inner_mode.family field from the xfrm state. This is unreliable. In tunnel mode, the state's actual inner family could be defined by x->inner_mode.family or by x->inner_mode_iaf.family. Checking only the former can lead to a mismatch with the actual packet being processed, causing GSO to create segments with the wrong L2 header type. This patch fixes the bug by deriving the inner mode directly from the packet's inner protocol stored in XFRM_MODE_SKB_CB(skb)->protocol. Fixes: 26dbd66eab80 ("esp: choose the correct inner protocol for GSO on inter address family tunnels") Signed-off-by: Jianbo Liu Reviewed-by: Cosmin Ratiu --- V2: - Change subject prefix, and send to "ipsec". - Add Fixes tag. net/ipv4/esp4_offload.c | 6 ++++-- net/ipv6/esp6_offload.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/ipv4/esp4_offload.c b/net/ipv4/esp4_offload.c index e0d94270da28..05828d4cb6cd 100644 --- a/net/ipv4/esp4_offload.c +++ b/net/ipv4/esp4_offload.c @@ -122,8 +122,10 @@ static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) { - __be16 type = x->inner_mode.family == AF_INET6 ? htons(ETH_P_IPV6) - : htons(ETH_P_IP); + const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x, + XFRM_MODE_SKB_CB(skb)->protocol); + __be16 type = inner_mode->family == AF_INET6 ? htons(ETH_P_IPV6) + : htons(ETH_P_IP); return skb_eth_gso_segment(skb, features, type); } diff --git a/net/ipv6/esp6_offload.c b/net/ipv6/esp6_offload.c index 7b41fb4f00b5..22410243ebe8 100644 --- a/net/ipv6/esp6_offload.c +++ b/net/ipv6/esp6_offload.c @@ -158,8 +158,10 @@ static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) { - __be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP) - : htons(ETH_P_IPV6); + const struct xfrm_mode *inner_mode = xfrm_ip2inner_mode(x, + XFRM_MODE_SKB_CB(skb)->protocol); + __be16 type = inner_mode->family == AF_INET ? htons(ETH_P_IP) + : htons(ETH_P_IPV6); return skb_eth_gso_segment(skb, features, type); } -- 2.49.0