From f1fb08f6337ca9e3af371a7994b91a5786ba93f9 Mon Sep 17 00:00:00 2001 From: Vincent Bernat Date: Sun, 2 Apr 2017 11:00:06 +0200 Subject: [PATCH] vxlan: fix ND proxy when skb doesn't have transport header offset When an incoming frame is tagged or when GRO is disabled, the skb handled to vxlan_xmit() doesn't contain a valid transport header offset. This makes ND proxying fail. We combine two changes: replace use of skb_transport_offset() and ensure the necessary amount of skb is linear just before using it: - In vxlan_xmit(), when determining if we have an ICMPv6 neighbor discovery packet, just check if it is an ICMPv6 packet and rely on neigh_reduce() to do more checks if this is the case. The use of pskb_may_pull() is replaced by skb_header_pointer() for just the IPv6 header. - In neigh_reduce(), add pskb_may_pull() for IPv6 header and neighbor discovery message since this was removed from vxlan_xmit(). Replace skb_transport_header() with ipv6_hdr() + 1. - In vxlan_na_create(), replace first skb_transport_offset() with ipv6_hdr() + 1 and second with skb_network_offset() + sizeof(struct ipv6hdr). Additionally, ensure we pskb_may_pull() the whole skb as we need it to iterate over the options. Signed-off-by: Vincent Bernat Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 714f74fb823a..ebc98bb17a51 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -1515,7 +1515,7 @@ static struct sk_buff *vxlan_na_create(struct sk_buff *request, int ns_olen; int i, len; - if (dev == NULL) + if (dev == NULL || !pskb_may_pull(request, request->len)) return NULL; len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) + @@ -1530,10 +1530,11 @@ static struct sk_buff *vxlan_na_create(struct sk_buff *request, skb_push(reply, sizeof(struct ethhdr)); skb_reset_mac_header(reply); - ns = (struct nd_msg *)skb_transport_header(request); + ns = (struct nd_msg *)(ipv6_hdr(request) + 1); daddr = eth_hdr(request)->h_source; - ns_olen = request->len - skb_transport_offset(request) - sizeof(*ns); + ns_olen = request->len - skb_network_offset(request) - + sizeof(struct ipv6hdr) - sizeof(*ns); for (i = 0; i < ns_olen-1; i += (ns->opt[i+1]<<3)) { if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) { daddr = ns->opt + i + sizeof(struct nd_opt_hdr); @@ -1604,10 +1605,13 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni) if (!in6_dev) goto out; + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg))) + goto out; + iphdr = ipv6_hdr(skb); daddr = &iphdr->daddr; - msg = (struct nd_msg *)skb_transport_header(skb); + msg = (struct nd_msg *)(iphdr + 1); if (msg->icmph.icmp6_code != 0 || msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION) goto out; @@ -2242,16 +2246,13 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev) if (ntohs(eth->h_proto) == ETH_P_ARP) return arp_reduce(dev, skb, vni); #if IS_ENABLED(CONFIG_IPV6) - else if (ntohs(eth->h_proto) == ETH_P_IPV6 && - pskb_may_pull(skb, sizeof(struct ipv6hdr) - + sizeof(struct nd_msg)) && - ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) { - struct nd_msg *msg; - - msg = (struct nd_msg *)skb_transport_header(skb); - if (msg->icmph.icmp6_code == 0 && - msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) - return neigh_reduce(dev, skb, vni); + else if (ntohs(eth->h_proto) == ETH_P_IPV6) { + struct ipv6hdr *hdr, _hdr; + if ((hdr = skb_header_pointer(skb, + skb_network_offset(skb), + sizeof(_hdr), &_hdr)) && + hdr->nexthdr == IPPROTO_ICMPV6) + return neigh_reduce(dev, skb, vni); } #endif } -- 2.30.2