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net/netfilter/nft_tproxy.c
8.17 KB
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/* SPDX-License-Identifier: GPL-2.0 */ #include <linux/module.h> #include <linux/netfilter/nf_tables.h> #include <net/netfilter/nf_tables.h> #include <net/netfilter/nf_tables_core.h> #include <net/netfilter/nf_tproxy.h> #include <net/inet_sock.h> #include <net/tcp.h> #include <linux/if_ether.h> #include <net/netfilter/ipv4/nf_defrag_ipv4.h> #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) #include <net/netfilter/ipv6/nf_defrag_ipv6.h> #endif struct nft_tproxy { enum nft_registers sreg_addr:8; enum nft_registers sreg_port:8; u8 family; }; static void nft_tproxy_eval_v4(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) { const struct nft_tproxy *priv = nft_expr_priv(expr); struct sk_buff *skb = pkt->skb; const struct iphdr *iph = ip_hdr(skb); struct udphdr _hdr, *hp; __be32 taddr = 0; __be16 tport = 0; struct sock *sk; hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr); if (!hp) { regs->verdict.code = NFT_BREAK; return; } /* check if there's an ongoing connection on the packet addresses, this * happens if the redirect already happened and the current packet * belongs to an already established connection */ sk = nf_tproxy_get_sock_v4(nft_net(pkt), skb, iph->protocol, iph->saddr, iph->daddr, hp->source, hp->dest, skb->dev, NF_TPROXY_LOOKUP_ESTABLISHED); if (priv->sreg_addr) taddr = regs->data[priv->sreg_addr]; taddr = nf_tproxy_laddr4(skb, taddr, iph->daddr); if (priv->sreg_port) |
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tport = nft_reg_load16(®s->data[priv->sreg_port]); |
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if (!tport) tport = hp->dest; /* UDP has no TCP_TIME_WAIT state, so we never enter here */ if (sk && sk->sk_state == TCP_TIME_WAIT) { /* reopening a TIME_WAIT connection needs special handling */ sk = nf_tproxy_handle_time_wait4(nft_net(pkt), skb, taddr, tport, sk); } else if (!sk) { /* no, there's no established connection, check if * there's a listener on the redirected addr/port */ sk = nf_tproxy_get_sock_v4(nft_net(pkt), skb, iph->protocol, iph->saddr, taddr, hp->source, tport, skb->dev, NF_TPROXY_LOOKUP_LISTENER); } if (sk && nf_tproxy_sk_is_transparent(sk)) nf_tproxy_assign_sock(skb, sk); else regs->verdict.code = NFT_BREAK; } #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) static void nft_tproxy_eval_v6(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) { const struct nft_tproxy *priv = nft_expr_priv(expr); struct sk_buff *skb = pkt->skb; const struct ipv6hdr *iph = ipv6_hdr(skb); |
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struct in6_addr taddr; |
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int thoff = pkt->xt.thoff; struct udphdr _hdr, *hp; __be16 tport = 0; struct sock *sk; int l4proto; |
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memset(&taddr, 0, sizeof(taddr)); |
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if (!pkt->tprot_set) { regs->verdict.code = NFT_BREAK; return; } l4proto = pkt->tprot; hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr); if (hp == NULL) { regs->verdict.code = NFT_BREAK; return; } /* check if there's an ongoing connection on the packet addresses, this * happens if the redirect already happened and the current packet * belongs to an already established connection */ sk = nf_tproxy_get_sock_v6(nft_net(pkt), skb, thoff, l4proto, &iph->saddr, &iph->daddr, hp->source, hp->dest, nft_in(pkt), NF_TPROXY_LOOKUP_ESTABLISHED); if (priv->sreg_addr) memcpy(&taddr, ®s->data[priv->sreg_addr], sizeof(taddr)); taddr = *nf_tproxy_laddr6(skb, &taddr, &iph->daddr); if (priv->sreg_port) |
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tport = nft_reg_load16(®s->data[priv->sreg_port]); |
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if (!tport) tport = hp->dest; /* UDP has no TCP_TIME_WAIT state, so we never enter here */ if (sk && sk->sk_state == TCP_TIME_WAIT) { /* reopening a TIME_WAIT connection needs special handling */ sk = nf_tproxy_handle_time_wait6(skb, l4proto, thoff, nft_net(pkt), &taddr, tport, sk); } else if (!sk) { /* no there's no established connection, check if * there's a listener on the redirected addr/port */ sk = nf_tproxy_get_sock_v6(nft_net(pkt), skb, thoff, l4proto, &iph->saddr, &taddr, hp->source, tport, nft_in(pkt), NF_TPROXY_LOOKUP_LISTENER); } /* NOTE: assign_sock consumes our sk reference */ if (sk && nf_tproxy_sk_is_transparent(sk)) nf_tproxy_assign_sock(skb, sk); else regs->verdict.code = NFT_BREAK; } #endif static void nft_tproxy_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) { const struct nft_tproxy *priv = nft_expr_priv(expr); switch (nft_pf(pkt)) { case NFPROTO_IPV4: switch (priv->family) { case NFPROTO_IPV4: case NFPROTO_UNSPEC: nft_tproxy_eval_v4(expr, regs, pkt); return; } break; #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) case NFPROTO_IPV6: switch (priv->family) { case NFPROTO_IPV6: case NFPROTO_UNSPEC: nft_tproxy_eval_v6(expr, regs, pkt); return; } #endif } regs->verdict.code = NFT_BREAK; } static const struct nla_policy nft_tproxy_policy[NFTA_TPROXY_MAX + 1] = { [NFTA_TPROXY_FAMILY] = { .type = NLA_U32 }, [NFTA_TPROXY_REG_ADDR] = { .type = NLA_U32 }, [NFTA_TPROXY_REG_PORT] = { .type = NLA_U32 }, }; static int nft_tproxy_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]) { struct nft_tproxy *priv = nft_expr_priv(expr); unsigned int alen = 0; int err; if (!tb[NFTA_TPROXY_FAMILY] || (!tb[NFTA_TPROXY_REG_ADDR] && !tb[NFTA_TPROXY_REG_PORT])) return -EINVAL; priv->family = ntohl(nla_get_be32(tb[NFTA_TPROXY_FAMILY])); switch (ctx->family) { case NFPROTO_IPV4: if (priv->family != NFPROTO_IPV4) return -EINVAL; break; #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) case NFPROTO_IPV6: if (priv->family != NFPROTO_IPV6) return -EINVAL; break; #endif case NFPROTO_INET: break; default: return -EOPNOTSUPP; } /* Address is specified but the rule family is not set accordingly */ if (priv->family == NFPROTO_UNSPEC && tb[NFTA_TPROXY_REG_ADDR]) return -EINVAL; switch (priv->family) { case NFPROTO_IPV4: |
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alen = sizeof_field(union nf_inet_addr, in); |
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err = nf_defrag_ipv4_enable(ctx->net); if (err) return err; break; #if IS_ENABLED(CONFIG_NF_TABLES_IPV6) case NFPROTO_IPV6: |
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alen = sizeof_field(union nf_inet_addr, in6); |
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err = nf_defrag_ipv6_enable(ctx->net); if (err) return err; break; #endif case NFPROTO_UNSPEC: /* No address is specified here */ err = nf_defrag_ipv4_enable(ctx->net); if (err) return err; |
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#if IS_ENABLED(CONFIG_NF_TABLES_IPV6) |
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err = nf_defrag_ipv6_enable(ctx->net); if (err) return err; |
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#endif |
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break; default: return -EOPNOTSUPP; } if (tb[NFTA_TPROXY_REG_ADDR]) { priv->sreg_addr = nft_parse_register(tb[NFTA_TPROXY_REG_ADDR]); err = nft_validate_register_load(priv->sreg_addr, alen); if (err < 0) return err; } if (tb[NFTA_TPROXY_REG_PORT]) { priv->sreg_port = nft_parse_register(tb[NFTA_TPROXY_REG_PORT]); err = nft_validate_register_load(priv->sreg_port, sizeof(u16)); if (err < 0) return err; } return 0; } static int nft_tproxy_dump(struct sk_buff *skb, const struct nft_expr *expr) { const struct nft_tproxy *priv = nft_expr_priv(expr); if (nla_put_be32(skb, NFTA_TPROXY_FAMILY, htonl(priv->family))) return -1; if (priv->sreg_addr && nft_dump_register(skb, NFTA_TPROXY_REG_ADDR, priv->sreg_addr)) return -1; if (priv->sreg_port && nft_dump_register(skb, NFTA_TPROXY_REG_PORT, priv->sreg_port)) return -1; return 0; } static struct nft_expr_type nft_tproxy_type; static const struct nft_expr_ops nft_tproxy_ops = { .type = &nft_tproxy_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_tproxy)), .eval = nft_tproxy_eval, .init = nft_tproxy_init, .dump = nft_tproxy_dump, }; static struct nft_expr_type nft_tproxy_type __read_mostly = { .name = "tproxy", .ops = &nft_tproxy_ops, .policy = nft_tproxy_policy, .maxattr = NFTA_TPROXY_MAX, .owner = THIS_MODULE, }; static int __init nft_tproxy_module_init(void) { return nft_register_expr(&nft_tproxy_type); } static void __exit nft_tproxy_module_exit(void) { nft_unregister_expr(&nft_tproxy_type); } module_init(nft_tproxy_module_init); module_exit(nft_tproxy_module_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Máté Eckl"); MODULE_DESCRIPTION("nf_tables tproxy support module"); MODULE_ALIAS_NFT_EXPR("tproxy"); |