ipvs: Fix checksumming on GSO of SCTP packets
authorIsmael Luceno <iluceno@suse.de>
Sun, 21 Apr 2024 14:22:32 +0000 (16:22 +0200)
committerPablo Neira Ayuso <pablo@netfilter.org>
Wed, 24 Apr 2024 22:22:48 +0000 (00:22 +0200)
It was observed in the wild that pairs of consecutive packets would leave
the IPVS with the same wrong checksum, and the issue only went away when
disabling GSO.

IPVS needs to avoid computing the SCTP checksum when using GSO.

Fixes: 90017accff61 ("sctp: Add GSO support")
Co-developed-by: Firo Yang <firo.yang@suse.com>
Signed-off-by: Ismael Luceno <iluceno@suse.de>
Tested-by: Andreas Taschner <andreas.taschner@suse.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
net/netfilter/ipvs/ip_vs_proto_sctp.c

index a0921ad..1e689c7 100644 (file)
@@ -126,7 +126,8 @@ sctp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
        if (sctph->source != cp->vport || payload_csum ||
            skb->ip_summed == CHECKSUM_PARTIAL) {
                sctph->source = cp->vport;
-               sctp_nat_csum(skb, sctph, sctphoff);
+               if (!skb_is_gso(skb) || !skb_is_gso_sctp(skb))
+                       sctp_nat_csum(skb, sctph, sctphoff);
        } else {
                skb->ip_summed = CHECKSUM_UNNECESSARY;
        }
@@ -174,7 +175,8 @@ sctp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
            (skb->ip_summed == CHECKSUM_PARTIAL &&
             !(skb_dst(skb)->dev->features & NETIF_F_SCTP_CRC))) {
                sctph->dest = cp->dport;
-               sctp_nat_csum(skb, sctph, sctphoff);
+               if (!skb_is_gso(skb) || !skb_is_gso_sctp(skb))
+                       sctp_nat_csum(skb, sctph, sctphoff);
        } else if (skb->ip_summed != CHECKSUM_PARTIAL) {
                skb->ip_summed = CHECKSUM_UNNECESSARY;
        }