diff options
Diffstat (limited to 'net/bridge/br_netfilter_ipv6.c')
| -rw-r--r-- | net/bridge/br_netfilter_ipv6.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c new file mode 100644 index 000000000000..6d12d2675c80 --- /dev/null +++ b/net/bridge/br_netfilter_ipv6.c @@ -0,0 +1,245 @@ +/* + * Handle firewalling + * Linux ethernet bridge + * + * Authors: + * Lennert Buytenhek <buytenh@gnu.org> + * Bart De Schuymer <bdschuym@pandora.be> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Lennert dedicates this file to Kerstin Wurdinger. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/ip.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/if_vlan.h> +#include <linux/if_pppox.h> +#include <linux/ppp_defs.h> +#include <linux/netfilter_bridge.h> +#include <linux/netfilter_ipv4.h> +#include <linux/netfilter_ipv6.h> +#include <linux/netfilter_arp.h> +#include <linux/in_route.h> +#include <linux/inetdevice.h> + +#include <net/ip.h> +#include <net/ipv6.h> +#include <net/addrconf.h> +#include <net/route.h> +#include <net/netfilter/br_netfilter.h> + +#include <asm/uaccess.h> +#include "br_private.h" +#ifdef CONFIG_SYSCTL +#include <linux/sysctl.h> +#endif + +/* We only check the length. A bridge shouldn't do any hop-by-hop stuff + * anyway + */ +static int br_nf_check_hbh_len(struct sk_buff *skb) +{ + unsigned char *raw = (u8 *)(ipv6_hdr(skb) + 1); + u32 pkt_len; + const unsigned char *nh = skb_network_header(skb); + int off = raw - nh; + int len = (raw[1] + 1) << 3; + + if ((raw + len) - skb->data > skb_headlen(skb)) + goto bad; + + off += 2; + len -= 2; + + while (len > 0) { + int optlen = nh[off + 1] + 2; + + switch (nh[off]) { + case IPV6_TLV_PAD1: + optlen = 1; + break; + + case IPV6_TLV_PADN: + break; + + case IPV6_TLV_JUMBO: + if (nh[off + 1] != 4 || (off & 3) != 2) + goto bad; + pkt_len = ntohl(*(__be32 *)(nh + off + 2)); + if (pkt_len <= IPV6_MAXPLEN || + ipv6_hdr(skb)->payload_len) + goto bad; + if (pkt_len > skb->len - sizeof(struct ipv6hdr)) + goto bad; + if (pskb_trim_rcsum(skb, + pkt_len + sizeof(struct ipv6hdr))) + goto bad; + nh = skb_network_header(skb); + break; + default: + if (optlen > len) + goto bad; + break; + } + off += optlen; + len -= optlen; + } + if (len == 0) + return 0; +bad: + return -1; +} + +int br_validate_ipv6(struct sk_buff *skb) +{ + const struct ipv6hdr *hdr; + struct net_device *dev = skb->dev; + struct inet6_dev *idev = in6_dev_get(skb->dev); + u32 pkt_len; + u8 ip6h_len = sizeof(struct ipv6hdr); + + if (!pskb_may_pull(skb, ip6h_len)) + goto inhdr_error; + + if (skb->len < ip6h_len) + goto drop; + + hdr = ipv6_hdr(skb); + + if (hdr->version != 6) + goto inhdr_error; + + pkt_len = ntohs(hdr->payload_len); + + if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { + if (pkt_len + ip6h_len > skb->len) { + IP6_INC_STATS_BH(dev_net(dev), idev, + IPSTATS_MIB_INTRUNCATEDPKTS); + goto drop; + } + if (pskb_trim_rcsum(skb, pkt_len + ip6h_len)) { + IP6_INC_STATS_BH(dev_net(dev), idev, + IPSTATS_MIB_INDISCARDS); + goto drop; + } + } + if (hdr->nexthdr == NEXTHDR_HOP && br_nf_check_hbh_len(skb)) + goto drop; + + memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); + /* No IP options in IPv6 header; however it should be + * checked if some next headers need special treatment + */ + return 0; + +inhdr_error: + IP6_INC_STATS_BH(dev_net(dev), idev, IPSTATS_MIB_INHDRERRORS); +drop: + return -1; +} + +static inline bool +br_nf_ipv6_daddr_was_changed(const struct sk_buff *skb, + const struct nf_bridge_info *nf_bridge) +{ + return memcmp(&nf_bridge->ipv6_daddr, &ipv6_hdr(skb)->daddr, + sizeof(ipv6_hdr(skb)->daddr)) != 0; +} + +/* PF_BRIDGE/PRE_ROUTING: Undo the changes made for ip6tables + * PREROUTING and continue the bridge PRE_ROUTING hook. See comment + * for br_nf_pre_routing_finish(), same logic is used here but + * equivalent IPv6 function ip6_route_input() called indirectly. + */ +static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb) +{ + struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb); + struct rtable *rt; + struct net_device *dev = skb->dev; + const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops(); + + nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size; + + if (nf_bridge->pkt_otherhost) { + skb->pkt_type = PACKET_OTHERHOST; + nf_bridge->pkt_otherhost = false; + } + nf_bridge->mask &= ~BRNF_NF_BRIDGE_PREROUTING; + if (br_nf_ipv6_daddr_was_changed(skb, nf_bridge)) { + skb_dst_drop(skb); + v6ops->route_input(skb); + + if (skb_dst(skb)->error) { + kfree_skb(skb); + return 0; + } + + if (skb_dst(skb)->dev == dev) { + skb->dev = nf_bridge->physindev; + nf_bridge_update_protocol(skb); + nf_bridge_push_encap_header(skb); + NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, + sk, skb, skb->dev, NULL, + br_nf_pre_routing_finish_bridge, + 1); + return 0; + } + ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr); + skb->pkt_type = PACKET_HOST; + } else { + rt = bridge_parent_rtable(nf_bridge->physindev); + if (!rt) { + kfree_skb(skb); + return 0; + } + skb_dst_set_noref(skb, &rt->dst); + } + + skb->dev = nf_bridge->physindev; + nf_bridge_update_protocol(skb); + nf_bridge_push_encap_header(skb); + NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb, + skb->dev, NULL, + br_handle_frame_finish, 1); + + return 0; +} + +/* Replicate the checks that IPv6 does on packet reception and pass the packet + * to ip6tables. + */ +unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops *ops, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct nf_bridge_info *nf_bridge; + + if (br_validate_ipv6(skb)) + return NF_DROP; + + nf_bridge_put(skb->nf_bridge); + if (!nf_bridge_alloc(skb)) + return NF_DROP; + if (!setup_pre_routing(skb)) + return NF_DROP; + + nf_bridge = nf_bridge_info_get(skb); + nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr; + + skb->protocol = htons(ETH_P_IPV6); + NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->sk, skb, + skb->dev, NULL, + br_nf_pre_routing_finish_ipv6); + + return NF_STOLEN; +} |