// SPDX-License-Identifier: GPL-2.0 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static DEFINE_MUTEX(nf_ct_proto_mutex); #ifdef CONFIG_SYSCTL __printf(4, 5) void nf_l4proto_log_invalid(const struct sk_buff *skb, const struct nf_hook_state *state, u8 protonum, const char *fmt, ...) { struct net *net = state->net; struct va_format vaf; va_list args; if (net->ct.sysctl_log_invalid != protonum && net->ct.sysctl_log_invalid != IPPROTO_RAW) return; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; nf_log_packet(net, state->pf, 0, skb, state->in, state->out, NULL, "nf_ct_proto_%d: %pV ", protonum, &vaf); va_end(args); } EXPORT_SYMBOL_GPL(nf_l4proto_log_invalid); __printf(4, 5) void nf_ct_l4proto_log_invalid(const struct sk_buff *skb, const struct nf_conn *ct, const struct nf_hook_state *state, const char *fmt, ...) { struct va_format vaf; struct net *net; va_list args; net = nf_ct_net(ct); if (likely(net->ct.sysctl_log_invalid == 0)) return; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; nf_l4proto_log_invalid(skb, state, nf_ct_protonum(ct), "%pV", &vaf); va_end(args); } EXPORT_SYMBOL_GPL(nf_ct_l4proto_log_invalid); #endif const struct nf_conntrack_l4proto *nf_ct_l4proto_find(u8 l4proto) { switch (l4proto) { case IPPROTO_UDP: return &nf_conntrack_l4proto_udp; case IPPROTO_TCP: return &nf_conntrack_l4proto_tcp; case IPPROTO_ICMP: return &nf_conntrack_l4proto_icmp; #ifdef CONFIG_NF_CT_PROTO_DCCP case IPPROTO_DCCP: return &nf_conntrack_l4proto_dccp; #endif #ifdef CONFIG_NF_CT_PROTO_SCTP case IPPROTO_SCTP: return &nf_conntrack_l4proto_sctp; #endif #ifdef CONFIG_NF_CT_PROTO_UDPLITE case IPPROTO_UDPLITE: return &nf_conntrack_l4proto_udplite; #endif #ifdef CONFIG_NF_CT_PROTO_GRE case IPPROTO_GRE: return &nf_conntrack_l4proto_gre; #endif #if IS_ENABLED(CONFIG_IPV6) case IPPROTO_ICMPV6: return &nf_conntrack_l4proto_icmpv6; #endif /* CONFIG_IPV6 */ } return &nf_conntrack_l4proto_generic; }; EXPORT_SYMBOL_GPL(nf_ct_l4proto_find); unsigned int nf_confirm(struct sk_buff *skb, unsigned int protoff, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { const struct nf_conn_help *help; help = nfct_help(ct); if (help) { const struct nf_conntrack_helper *helper; int ret; /* rcu_read_lock()ed by nf_hook_thresh */ helper = rcu_dereference(help->helper); if (helper) { ret = helper->help(skb, protoff, ct, ctinfo); if (ret != NF_ACCEPT) return ret; } } if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && !nf_is_loopback_packet(skb)) { if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) { NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop); return NF_DROP; } } /* We've seen it coming out the other side: confirm it */ return nf_conntrack_confirm(skb); } EXPORT_SYMBOL_GPL(nf_confirm); static bool in_vrf_postrouting(const struct nf_hook_state *state) { #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) if (state->hook == NF_INET_POST_ROUTING && netif_is_l3_master(state->out)) return true; #endif return false; } static unsigned int ipv4_confirm(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { enum ip_conntrack_info ctinfo; struct nf_conn *ct; ct = nf_ct_get(skb, &ctinfo); if (!ct || ctinfo == IP_CT_RELATED_REPLY) return nf_conntrack_confirm(skb); if (in_vrf_postrouting(state)) return NF_ACCEPT; return nf_confirm(skb, skb_network_offset(skb) + ip_hdrlen(skb), ct, ctinfo); } static unsigned int ipv4_conntrack_in(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { return nf_conntrack_in(skb, state); } static unsigned int ipv4_conntrack_local(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { if (ip_is_fragment(ip_hdr(skb))) { /* IP_NODEFRAG setsockopt set */ enum ip_conntrack_info ctinfo; struct nf_conn *tmpl; tmpl = nf_ct_get(skb, &ctinfo); if (tmpl && nf_ct_is_template(tmpl)) { /* when skipping ct, clear templates to avoid fooling * later targets/matches */ skb->_nfct = 0; nf_ct_put(tmpl); } return NF_ACCEPT; } return nf_conntrack_in(skb, state); } /* Connection tracking may drop packets, but never alters them, so * make it the first hook. */ static const struct nf_hook_ops ipv4_conntrack_ops[] = { { .hook = ipv4_conntrack_in, .pf = NFPROTO_IPV4, .hooknum = NF_INET_PRE_ROUTING, .priority = NF_IP_PRI_CONNTRACK, }, { .hook = ipv4_conntrack_local, .pf = NFPROTO_IPV4, .hooknum = NF_INET_LOCAL_OUT, .priority = NF_IP_PRI_CONNTRACK, }, { .hook = ipv4_confirm, .pf = NFPROTO_IPV4, .hooknum = NF_INET_POST_ROUTING, .priority = NF_IP_PRI_CONNTRACK_CONFIRM, }, { .hook = ipv4_confirm, .pf = NFPROTO_IPV4, .hooknum = NF_INET_LOCAL_IN, .priority = NF_IP_PRI_CONNTRACK_CONFIRM, }, }; /* Fast function for those who don't want to parse /proc (and I don't * blame them). * Reversing the socket's dst/src point of view gives us the reply * mapping. */ static int getorigdst(struct sock *sk, int optval, void __user *user, int *len) { const struct inet_sock *inet = inet_sk(sk); const struct nf_conntrack_tuple_hash *h; struct nf_conntrack_tuple tuple; memset(&tuple, 0, sizeof(tuple)); lock_sock(sk); tuple.src.u3.ip = inet->inet_rcv_saddr; tuple.src.u.tcp.port = inet->inet_sport; tuple.dst.u3.ip = inet->inet_daddr; tuple.dst.u.tcp.port = inet->inet_dport; tuple.src.l3num = PF_INET; tuple.dst.protonum = sk->sk_protocol; release_sock(sk); /* We only do TCP and SCTP at the moment: is there a better way? */ if (tuple.dst.protonum != IPPROTO_TCP && tuple.dst.protonum != IPPROTO_SCTP) { pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n"); return -ENOPROTOOPT; } if ((unsigned int)*len < sizeof(struct sockaddr_in)) { pr_debug("SO_ORIGINAL_DST: len %d not %zu\n", *len, sizeof(struct sockaddr_in)); return -EINVAL; } h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple); if (h) { struct sockaddr_in sin; struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); sin.sin_family = AF_INET; sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL] .tuple.dst.u.tcp.port; sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL] .tuple.dst.u3.ip; memset(sin.sin_zero, 0, sizeof(sin.sin_zero)); pr_debug("SO_ORIGINAL_DST: %pI4 %u\n", &sin.sin_addr.s_addr, ntohs(sin.sin_port)); nf_ct_put(ct); if (copy_to_user(user, &sin, sizeof(sin)) != 0) return -EFAULT; else return 0; } pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n", &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port), &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port)); return -ENOENT; } static struct nf_sockopt_ops so_getorigdst = { .pf = PF_INET, .get_optmin = SO_ORIGINAL_DST, .get_optmax = SO_ORIGINAL_DST + 1, .get = getorigdst, .owner = THIS_MODULE, }; #if IS_ENABLED(CONFIG_IPV6) static int ipv6_getorigdst(struct sock *sk, int optval, void __user *user, int *len) { struct nf_conntrack_tuple tuple = { .src.l3num = NFPROTO_IPV6 }; const struct ipv6_pinfo *inet6 = inet6_sk(sk); const struct inet_sock *inet = inet_sk(sk); const struct nf_conntrack_tuple_hash *h; struct sockaddr_in6 sin6; struct nf_conn *ct; __be32 flow_label; int bound_dev_if; lock_sock(sk); tuple.src.u3.in6 = sk->sk_v6_rcv_saddr; tuple.src.u.tcp.port = inet->inet_sport; tuple.dst.u3.in6 = sk->sk_v6_daddr; tuple.dst.u.tcp.port = inet->inet_dport; tuple.dst.protonum = sk->sk_protocol; bound_dev_if = sk->sk_bound_dev_if; flow_label = inet6->flow_label; release_sock(sk); if (tuple.dst.protonum != IPPROTO_TCP && tuple.dst.protonum != IPPROTO_SCTP) return -ENOPROTOOPT; if (*len < 0 || (unsigned int)*len < sizeof(sin6)) return -EINVAL; h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple); if (!h) { pr_debug("IP6T_SO_ORIGINAL_DST: Can't find %pI6c/%u-%pI6c/%u.\n", &tuple.src.u3.ip6, ntohs(tuple.src.u.tcp.port), &tuple.dst.u3.ip6, ntohs(tuple.dst.u.tcp.port)); return -ENOENT; } ct = nf_ct_tuplehash_to_ctrack(h); sin6.sin6_family = AF_INET6; sin6.sin6_port = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port; sin6.sin6_flowinfo = flow_label & IPV6_FLOWINFO_MASK; memcpy(&sin6.sin6_addr, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6, sizeof(sin6.sin6_addr)); nf_ct_put(ct); sin6.sin6_scope_id = ipv6_iface_scope_id(&sin6.sin6_addr, bound_dev_if); return copy_to_user(user, &sin6, sizeof(sin6)) ? -EFAULT : 0; } static struct nf_sockopt_ops so_getorigdst6 = { .pf = NFPROTO_IPV6, .get_optmin = IP6T_SO_ORIGINAL_DST, .get_optmax = IP6T_SO_ORIGINAL_DST + 1, .get = ipv6_getorigdst, .owner = THIS_MODULE, }; static unsigned int ipv6_confirm(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { struct nf_conn *ct; enum ip_conntrack_info ctinfo; unsigned char pnum = ipv6_hdr(skb)->nexthdr; __be16 frag_off; int protoff; ct = nf_ct_get(skb, &ctinfo); if (!ct || ctinfo == IP_CT_RELATED_REPLY) return nf_conntrack_confirm(skb); if (in_vrf_postrouting(state)) return NF_ACCEPT; protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum, &frag_off); if (protoff < 0 || (frag_off & htons(~0x7)) != 0) { pr_debug("proto header not found\n"); return nf_conntrack_confirm(skb); } return nf_confirm(skb, protoff, ct, ctinfo); } static unsigned int ipv6_conntrack_in(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { return nf_conntrack_in(skb, state); } static unsigned int ipv6_conntrack_local(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { return nf_conntrack_in(skb, state); } static const struct nf_hook_ops ipv6_conntrack_ops[] = { { .hook = ipv6_conntrack_in, .pf = NFPROTO_IPV6, .hooknum = NF_INET_PRE_ROUTING, .priority = NF_IP6_PRI_CONNTRACK, }, { .hook = ipv6_conntrack_local, .pf = NFPROTO_IPV6, .hooknum = NF_INET_LOCAL_OUT, .priority = NF_IP6_PRI_CONNTRACK, }, { .hook = ipv6_confirm, .pf = NFPROTO_IPV6, .hooknum = NF_INET_POST_ROUTING, .priority = NF_IP6_PRI_LAST, }, { .hook = ipv6_confirm, .pf = NFPROTO_IPV6, .hooknum = NF_INET_LOCAL_IN, .priority = NF_IP6_PRI_LAST - 1, }, }; #endif static int nf_ct_tcp_fixup(struct nf_conn *ct, void *_nfproto) { u8 nfproto = (unsigned long)_nfproto; if (nf_ct_l3num(ct) != nfproto) return 0; if (nf_ct_protonum(ct) == IPPROTO_TCP && ct->proto.tcp.state == TCP_CONNTRACK_ESTABLISHED) { ct->proto.tcp.seen[0].td_maxwin = 0; ct->proto.tcp.seen[1].td_maxwin = 0; } return 0; } static struct nf_ct_bridge_info *nf_ct_bridge_info; static int nf_ct_netns_do_get(struct net *net, u8 nfproto) { struct nf_conntrack_net *cnet = nf_ct_pernet(net); bool fixup_needed = false, retry = true; int err = 0; retry: mutex_lock(&nf_ct_proto_mutex); switch (nfproto) { case NFPROTO_IPV4: cnet->users4++; if (cnet->users4 > 1) goto out_unlock; err = nf_defrag_ipv4_enable(net); if (err) { cnet->users4 = 0; goto out_unlock; } err = nf_register_net_hooks(net, ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); if (err) cnet->users4 = 0; else fixup_needed = true; break; #if IS_ENABLED(CONFIG_IPV6) case NFPROTO_IPV6: cnet->users6++; if (cnet->users6 > 1) goto out_unlock; err = nf_defrag_ipv6_enable(net); if (err < 0) { cnet->users6 = 0; goto out_unlock; } err = nf_register_net_hooks(net, ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); if (err) cnet->users6 = 0; else fixup_needed = true; break; #endif case NFPROTO_BRIDGE: if (!nf_ct_bridge_info) { if (!retry) { err = -EPROTO; goto out_unlock; } mutex_unlock(&nf_ct_proto_mutex); request_module("nf_conntrack_bridge"); retry = false; goto retry; } if (!try_module_get(nf_ct_bridge_info->me)) { err = -EPROTO; goto out_unlock; } cnet->users_bridge++; if (cnet->users_bridge > 1) goto out_unlock; err = nf_register_net_hooks(net, nf_ct_bridge_info->ops, nf_ct_bridge_info->ops_size); if (err) cnet->users_bridge = 0; else fixup_needed = true; break; default: err = -EPROTO; break; } out_unlock: mutex_unlock(&nf_ct_proto_mutex); if (fixup_needed) nf_ct_iterate_cleanup_net(net, nf_ct_tcp_fixup, (void *)(unsigned long)nfproto, 0, 0); return err; } static void nf_ct_netns_do_put(struct net *net, u8 nfproto) { struct nf_conntrack_net *cnet = nf_ct_pernet(net); mutex_lock(&nf_ct_proto_mutex); switch (nfproto) { case NFPROTO_IPV4: if (cnet->users4 && (--cnet->users4 == 0)) { nf_unregister_net_hooks(net, ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); nf_defrag_ipv4_disable(net); } break; #if IS_ENABLED(CONFIG_IPV6) case NFPROTO_IPV6: if (cnet->users6 && (--cnet->users6 == 0)) { nf_unregister_net_hooks(net, ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); nf_defrag_ipv6_disable(net); } break; #endif case NFPROTO_BRIDGE: if (!nf_ct_bridge_info) break; if (cnet->users_bridge && (--cnet->users_bridge == 0)) nf_unregister_net_hooks(net, nf_ct_bridge_info->ops, nf_ct_bridge_info->ops_size); module_put(nf_ct_bridge_info->me); break; } mutex_unlock(&nf_ct_proto_mutex); } static int nf_ct_netns_inet_get(struct net *net) { int err; err = nf_ct_netns_do_get(net, NFPROTO_IPV4); #if IS_ENABLED(CONFIG_IPV6) if (err < 0) goto err1; err = nf_ct_netns_do_get(net, NFPROTO_IPV6); if (err < 0) goto err2; return err; err2: nf_ct_netns_put(net, NFPROTO_IPV4); err1: #endif return err; } int nf_ct_netns_get(struct net *net, u8 nfproto) { int err; switch (nfproto) { case NFPROTO_INET: err = nf_ct_netns_inet_get(net); break; case NFPROTO_BRIDGE: err = nf_ct_netns_do_get(net, NFPROTO_BRIDGE); if (err < 0) return err; err = nf_ct_netns_inet_get(net); if (err < 0) { nf_ct_netns_put(net, NFPROTO_BRIDGE); return err; } break; default: err = nf_ct_netns_do_get(net, nfproto); break; } return err; } EXPORT_SYMBOL_GPL(nf_ct_netns_get); void nf_ct_netns_put(struct net *net, uint8_t nfproto) { switch (nfproto) { case NFPROTO_BRIDGE: nf_ct_netns_do_put(net, NFPROTO_BRIDGE); fallthrough; case NFPROTO_INET: nf_ct_netns_do_put(net, NFPROTO_IPV4); nf_ct_netns_do_put(net, NFPROTO_IPV6); break; default: nf_ct_netns_do_put(net, nfproto); break; } } EXPORT_SYMBOL_GPL(nf_ct_netns_put); void nf_ct_bridge_register(struct nf_ct_bridge_info *info) { WARN_ON(nf_ct_bridge_info); mutex_lock(&nf_ct_proto_mutex); nf_ct_bridge_info = info; mutex_unlock(&nf_ct_proto_mutex); } EXPORT_SYMBOL_GPL(nf_ct_bridge_register); void nf_ct_bridge_unregister(struct nf_ct_bridge_info *info) { WARN_ON(!nf_ct_bridge_info); mutex_lock(&nf_ct_proto_mutex); nf_ct_bridge_info = NULL; mutex_unlock(&nf_ct_proto_mutex); } EXPORT_SYMBOL_GPL(nf_ct_bridge_unregister); int nf_conntrack_proto_init(void) { int ret; ret = nf_register_sockopt(&so_getorigdst); if (ret < 0) return ret; #if IS_ENABLED(CONFIG_IPV6) ret = nf_register_sockopt(&so_getorigdst6); if (ret < 0) goto cleanup_sockopt; #endif return ret; #if IS_ENABLED(CONFIG_IPV6) cleanup_sockopt: nf_unregister_sockopt(&so_getorigdst); #endif return ret; } void nf_conntrack_proto_fini(void) { nf_unregister_sockopt(&so_getorigdst); #if IS_ENABLED(CONFIG_IPV6) nf_unregister_sockopt(&so_getorigdst6); #endif } void nf_conntrack_proto_pernet_init(struct net *net) { nf_conntrack_generic_init_net(net); nf_conntrack_udp_init_net(net); nf_conntrack_tcp_init_net(net); nf_conntrack_icmp_init_net(net); #if IS_ENABLED(CONFIG_IPV6) nf_conntrack_icmpv6_init_net(net); #endif #ifdef CONFIG_NF_CT_PROTO_DCCP nf_conntrack_dccp_init_net(net); #endif #ifdef CONFIG_NF_CT_PROTO_SCTP nf_conntrack_sctp_init_net(net); #endif #ifdef CONFIG_NF_CT_PROTO_GRE nf_conntrack_gre_init_net(net); #endif } module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, &nf_conntrack_htable_size, 0600); MODULE_ALIAS("ip_conntrack"); MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET)); MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6)); MODULE_LICENSE("GPL");