udpv6: Handle large incoming UDP/IPv6 packets and support software UFO

- validate and forward GSO UDP/IPv6 packets from untrusted sources.
- do software UFO if the outgoing device doesn't support UFO.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 3 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index caa0278d30a9..bf85d5f97032 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -772,6 +772,11 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
         struct sk_buff *segs = ERR_PTR(-EINVAL);
         struct ipv6hdr *ipv6h;
         struct inet6_protocol *ops;
+        int proto;
+        struct frag_hdr *fptr;
+        unsigned int unfrag_ip6hlen;
+        u8 *prevhdr;
+        int offset = 0;
 
         if (!(features & NETIF_F_V6_CSUM))
                 features &= ~NETIF_F_SG;
@@ -791,10 +796,9 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
         __skb_pull(skb, sizeof(*ipv6h));
         segs = ERR_PTR(-EPROTONOSUPPORT);
 
+        proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
         rcu_read_lock();
-        ops = rcu_dereference(inet6_protos[
-                ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]);
-
+        ops = rcu_dereference(inet6_protos[proto]);
         if (likely(ops && ops->gso_segment)) {
                 skb_reset_transport_header(skb);
                 segs = ops->gso_segment(skb, features);
@@ -808,6 +812,16 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
                 ipv6h = ipv6_hdr(skb);
                 ipv6h->payload_len = htons(skb->len - skb->mac_len -
                                            sizeof(*ipv6h));
+                if (proto == IPPROTO_UDP) {
+                        unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
+                        fptr = (struct frag_hdr *)(skb_network_header(skb) +
+                                unfrag_ip6hlen);
+                        fptr->frag_off = htons(offset);
+                        if (skb->next != NULL)
+                                fptr->frag_off |= htons(IP6_MF);
+                        offset += (ntohs(ipv6h->payload_len) -
+                                   sizeof(struct frag_hdr));
+                }
         }
 
 out: