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>
This commit is contained in:
Sridhar Samudrala
David S. Miller
parent
7ea2f2c5a6
commit
ba73542585
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@ -772,6 +772,11 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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struct ipv6hdr *ipv6h;
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struct inet6_protocol *ops;
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int proto;
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struct frag_hdr *fptr;
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unsigned int unfrag_ip6hlen;
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u8 *prevhdr;
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int offset = 0;
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if (!(features & NETIF_F_V6_CSUM))
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features &= ~NETIF_F_SG;
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@ -791,10 +796,9 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
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__skb_pull(skb, sizeof(*ipv6h));
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segs = ERR_PTR(-EPROTONOSUPPORT);
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proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
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rcu_read_lock();
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ops = rcu_dereference(inet6_protos[
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ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]);
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ops = rcu_dereference(inet6_protos[proto]);
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if (likely(ops && ops->gso_segment)) {
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skb_reset_transport_header(skb);
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segs = ops->gso_segment(skb, features);
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@ -808,6 +812,16 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
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ipv6h = ipv6_hdr(skb);
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ipv6h->payload_len = htons(skb->len - skb->mac_len -
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sizeof(*ipv6h));
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if (proto == IPPROTO_UDP) {
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unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
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fptr = (struct frag_hdr *)(skb_network_header(skb) +
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unfrag_ip6hlen);
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fptr->frag_off = htons(offset);
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if (skb->next != NULL)
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fptr->frag_off |= htons(IP6_MF);
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offset += (ntohs(ipv6h->payload_len) -
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sizeof(struct frag_hdr));
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}
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}
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out:
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@ -1078,9 +1078,102 @@ int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
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}
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#endif
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static int udp6_ufo_send_check(struct sk_buff *skb)
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{
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struct ipv6hdr *ipv6h;
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struct udphdr *uh;
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if (!pskb_may_pull(skb, sizeof(*uh)))
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return -EINVAL;
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ipv6h = ipv6_hdr(skb);
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uh = udp_hdr(skb);
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uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
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IPPROTO_UDP, 0);
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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skb->ip_summed = CHECKSUM_PARTIAL;
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return 0;
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}
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static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, int features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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unsigned int mss;
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unsigned int unfrag_ip6hlen, unfrag_len;
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struct frag_hdr *fptr;
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u8 *mac_start, *prevhdr;
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u8 nexthdr;
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u8 frag_hdr_sz = sizeof(struct frag_hdr);
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int offset;
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__wsum csum;
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mss = skb_shinfo(skb)->gso_size;
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if (unlikely(skb->len <= mss))
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goto out;
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
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/* Packet is from an untrusted source, reset gso_segs. */
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int type = skb_shinfo(skb)->gso_type;
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if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
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!(type & (SKB_GSO_UDP))))
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goto out;
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skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
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segs = NULL;
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goto out;
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}
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/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
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* do checksum of UDP packets sent as multiple IP fragments.
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*/
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offset = skb->csum_start - skb_headroom(skb);
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csum = skb_checksum(skb, offset, skb->len- offset, 0);
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offset += skb->csum_offset;
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*(__sum16 *)(skb->data + offset) = csum_fold(csum);
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skb->ip_summed = CHECKSUM_NONE;
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/* Check if there is enough headroom to insert fragment header. */
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if ((skb_headroom(skb) < frag_hdr_sz) &&
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pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
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goto out;
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/* Find the unfragmentable header and shift it left by frag_hdr_sz
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* bytes to insert fragment header.
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*/
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unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
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nexthdr = *prevhdr;
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*prevhdr = NEXTHDR_FRAGMENT;
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unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
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unfrag_ip6hlen;
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mac_start = skb_mac_header(skb);
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memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
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skb->mac_header -= frag_hdr_sz;
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skb->network_header -= frag_hdr_sz;
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fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
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fptr->nexthdr = nexthdr;
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fptr->reserved = 0;
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ipv6_select_ident(fptr);
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/* Fragment the skb. ipv6 header and the remaining fields of the
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* fragment header are updated in ipv6_gso_segment()
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*/
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segs = skb_segment(skb, features);
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out:
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return segs;
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}
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static struct inet6_protocol udpv6_protocol = {
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.handler = udpv6_rcv,
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.err_handler = udpv6_err,
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.gso_send_check = udp6_ufo_send_check,
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.gso_segment = udp6_ufo_fragment,
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.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};
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