diff options
Diffstat (limited to 'net/netfilter/xt_addrtype.c')
-rw-r--r-- | net/netfilter/xt_addrtype.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/net/netfilter/xt_addrtype.c b/net/netfilter/xt_addrtype.c new file mode 100644 index 0000000..2220b85 --- /dev/null +++ b/net/netfilter/xt_addrtype.c @@ -0,0 +1,229 @@ +/* + * iptables module to match inet_addr_type() of an ip. + * + * Copyright (c) 2004 Patrick McHardy <kaber@trash.net> + * (C) 2007 Laszlo Attila Toth <panther@balabit.hu> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/ip.h> +#include <net/route.h> + +#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) +#include <net/ipv6.h> +#include <net/ip6_route.h> +#include <net/ip6_fib.h> +#endif + +#include <linux/netfilter/xt_addrtype.h> +#include <linux/netfilter/x_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); +MODULE_DESCRIPTION("Xtables: address type match"); +MODULE_ALIAS("ipt_addrtype"); +MODULE_ALIAS("ip6t_addrtype"); + +#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) +static u32 xt_addrtype_rt6_to_type(const struct rt6_info *rt) +{ + u32 ret; + + if (!rt) + return XT_ADDRTYPE_UNREACHABLE; + + if (rt->rt6i_flags & RTF_REJECT) + ret = XT_ADDRTYPE_UNREACHABLE; + else + ret = 0; + + if (rt->rt6i_flags & RTF_LOCAL) + ret |= XT_ADDRTYPE_LOCAL; + if (rt->rt6i_flags & RTF_ANYCAST) + ret |= XT_ADDRTYPE_ANYCAST; + return ret; +} + +static bool match_type6(struct net *net, const struct net_device *dev, + const struct in6_addr *addr, u16 mask) +{ + int addr_type = ipv6_addr_type(addr); + + if ((mask & XT_ADDRTYPE_MULTICAST) && + !(addr_type & IPV6_ADDR_MULTICAST)) + return false; + if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST)) + return false; + if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY) + return false; + + if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST | + XT_ADDRTYPE_UNREACHABLE) & mask) { + struct rt6_info *rt; + u32 type; + int ifindex = dev ? dev->ifindex : 0; + + rt = rt6_lookup(net, addr, NULL, ifindex, !!dev); + + type = xt_addrtype_rt6_to_type(rt); + + dst_release(&rt->dst); + return !!(mask & type); + } + return true; +} + +static bool +addrtype_mt6(struct net *net, const struct net_device *dev, + const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info) +{ + const struct ipv6hdr *iph = ipv6_hdr(skb); + bool ret = true; + + if (info->source) + ret &= match_type6(net, dev, &iph->saddr, info->source) ^ + (info->flags & XT_ADDRTYPE_INVERT_SOURCE); + if (ret && info->dest) + ret &= match_type6(net, dev, &iph->daddr, info->dest) ^ + !!(info->flags & XT_ADDRTYPE_INVERT_DEST); + return ret; +} +#endif + +static inline bool match_type(struct net *net, const struct net_device *dev, + __be32 addr, u_int16_t mask) +{ + return !!(mask & (1 << inet_dev_addr_type(net, dev, addr))); +} + +static bool +addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) +{ + struct net *net = dev_net(par->in ? par->in : par->out); + const struct xt_addrtype_info *info = par->matchinfo; + const struct iphdr *iph = ip_hdr(skb); + bool ret = true; + + if (info->source) + ret &= match_type(net, NULL, iph->saddr, info->source) ^ + info->invert_source; + if (info->dest) + ret &= match_type(net, NULL, iph->daddr, info->dest) ^ + info->invert_dest; + + return ret; +} + +static bool +addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) +{ + struct net *net = dev_net(par->in ? par->in : par->out); + const struct xt_addrtype_info_v1 *info = par->matchinfo; + const struct iphdr *iph; + const struct net_device *dev = NULL; + bool ret = true; + + if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) + dev = par->in; + else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) + dev = par->out; + +#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) + if (par->family == NFPROTO_IPV6) + return addrtype_mt6(net, dev, skb, info); +#endif + iph = ip_hdr(skb); + if (info->source) + ret &= match_type(net, dev, iph->saddr, info->source) ^ + (info->flags & XT_ADDRTYPE_INVERT_SOURCE); + if (ret && info->dest) + ret &= match_type(net, dev, iph->daddr, info->dest) ^ + !!(info->flags & XT_ADDRTYPE_INVERT_DEST); + return ret; +} + +static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par) +{ + struct xt_addrtype_info_v1 *info = par->matchinfo; + + if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN && + info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) { + pr_info("both incoming and outgoing " + "interface limitation cannot be selected\n"); + return -EINVAL; + } + + if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) | + (1 << NF_INET_LOCAL_IN)) && + info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) { + pr_info("output interface limitation " + "not valid in PREROUTING and INPUT\n"); + return -EINVAL; + } + + if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) | + (1 << NF_INET_LOCAL_OUT)) && + info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) { + pr_info("input interface limitation " + "not valid in POSTROUTING and OUTPUT\n"); + return -EINVAL; + } + +#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE) + if (par->family == NFPROTO_IPV6) { + if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) { + pr_err("ipv6 BLACKHOLE matching not supported\n"); + return -EINVAL; + } + if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) { + pr_err("ipv6 PROHIBT (THROW, NAT ..) matching not supported\n"); + return -EINVAL; + } + if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) { + pr_err("ipv6 does not support BROADCAST matching\n"); + return -EINVAL; + } + } +#endif + return 0; +} + +static struct xt_match addrtype_mt_reg[] __read_mostly = { + { + .name = "addrtype", + .family = NFPROTO_IPV4, + .match = addrtype_mt_v0, + .matchsize = sizeof(struct xt_addrtype_info), + .me = THIS_MODULE + }, + { + .name = "addrtype", + .family = NFPROTO_UNSPEC, + .revision = 1, + .match = addrtype_mt_v1, + .checkentry = addrtype_mt_checkentry_v1, + .matchsize = sizeof(struct xt_addrtype_info_v1), + .me = THIS_MODULE + } +}; + +static int __init addrtype_mt_init(void) +{ + return xt_register_matches(addrtype_mt_reg, + ARRAY_SIZE(addrtype_mt_reg)); +} + +static void __exit addrtype_mt_exit(void) +{ + xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg)); +} + +module_init(addrtype_mt_init); +module_exit(addrtype_mt_exit); |