From 51b0a5d8c21a91801bbef9bcc8639dc0b206c6cd Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 26 Sep 2014 14:35:14 +0200 Subject: netfilter: nft_reject: introduce icmp code abstraction for inet and bridge This patch introduces the NFT_REJECT_ICMPX_UNREACH type which provides an abstraction to the ICMP and ICMPv6 codes that you can use from the inet and bridge tables, they are: * NFT_REJECT_ICMPX_NO_ROUTE: no route to host - network unreachable * NFT_REJECT_ICMPX_PORT_UNREACH: port unreachable * NFT_REJECT_ICMPX_HOST_UNREACH: host unreachable * NFT_REJECT_ICMPX_ADMIN_PROHIBITED: administratevely prohibited You can still use the specific codes when restricting the rule to match the corresponding layer 3 protocol. I decided to not overload the existing NFT_REJECT_ICMP_UNREACH to have different semantics depending on the table family and to allow the user to specify ICMP family specific codes if they restrict it to the corresponding family. Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nft_reject_ipv4.c | 1 - 1 file changed, 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c index e79718a382f2..ed33299c56d1 100644 --- a/net/ipv4/netfilter/nft_reject_ipv4.c +++ b/net/ipv4/netfilter/nft_reject_ipv4.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include -- cgit v1.2.2 From c8d7b98bec43faaa6583c3135030be5eb4693acb Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 26 Sep 2014 14:35:15 +0200 Subject: netfilter: move nf_send_resetX() code to nf_reject_ipvX modules Move nf_send_reset() and nf_send_reset6() to nf_reject_ipv4 and nf_reject_ipv6 respectively. This code is shared by x_tables and nf_tables. Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/Kconfig | 6 ++ net/ipv4/netfilter/Makefile | 3 + net/ipv4/netfilter/nf_reject_ipv4.c | 127 ++++++++++++++++++++++++++++++++++++ 3 files changed, 136 insertions(+) create mode 100644 net/ipv4/netfilter/nf_reject_ipv4.c (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index 345242a79db6..4c019d5c3f57 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -61,8 +61,13 @@ config NFT_CHAIN_ROUTE_IPV4 fields such as the source, destination, type of service and the packet mark. +config NF_REJECT_IPV4 + tristate "IPv4 packet rejection" + default m if NETFILTER_ADVANCED=n + config NFT_REJECT_IPV4 depends on NF_TABLES_IPV4 + select NF_REJECT_IPV4 default NFT_REJECT tristate @@ -208,6 +213,7 @@ config IP_NF_FILTER config IP_NF_TARGET_REJECT tristate "REJECT target support" depends on IP_NF_FILTER + select NF_REJECT_IPV4 default m if NETFILTER_ADVANCED=n help The REJECT target allows a filtering rule to specify that an ICMP diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile index 14488cc5fd2c..f4cef5af0969 100644 --- a/net/ipv4/netfilter/Makefile +++ b/net/ipv4/netfilter/Makefile @@ -23,6 +23,9 @@ obj-$(CONFIG_NF_DEFRAG_IPV4) += nf_defrag_ipv4.o obj-$(CONFIG_NF_LOG_ARP) += nf_log_arp.o obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o +# reject +obj-$(CONFIG_NF_REJECT_IPV4) += nf_reject_ipv4.o + # NAT helpers (nf_conntrack) obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c new file mode 100644 index 000000000000..b023b4eb1a96 --- /dev/null +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -0,0 +1,127 @@ +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team + * + * 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. + */ + +#include +#include +#include +#include +#include + +/* Send RST reply */ +void nf_send_reset(struct sk_buff *oldskb, int hook) +{ + struct sk_buff *nskb; + const struct iphdr *oiph; + struct iphdr *niph; + const struct tcphdr *oth; + struct tcphdr _otcph, *tcph; + + /* IP header checks: fragment. */ + if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET)) + return; + + oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb), + sizeof(_otcph), &_otcph); + if (oth == NULL) + return; + + /* No RST for RST. */ + if (oth->rst) + return; + + if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) + return; + + /* Check checksum */ + if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP)) + return; + oiph = ip_hdr(oldskb); + + nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) + + LL_MAX_HEADER, GFP_ATOMIC); + if (!nskb) + return; + + skb_reserve(nskb, LL_MAX_HEADER); + + skb_reset_network_header(nskb); + niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr)); + niph->version = 4; + niph->ihl = sizeof(struct iphdr) / 4; + niph->tos = 0; + niph->id = 0; + niph->frag_off = htons(IP_DF); + niph->protocol = IPPROTO_TCP; + niph->check = 0; + niph->saddr = oiph->daddr; + niph->daddr = oiph->saddr; + + skb_reset_transport_header(nskb); + tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr)); + memset(tcph, 0, sizeof(*tcph)); + tcph->source = oth->dest; + tcph->dest = oth->source; + tcph->doff = sizeof(struct tcphdr) / 4; + + if (oth->ack) + tcph->seq = oth->ack_seq; + else { + tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin + + oldskb->len - ip_hdrlen(oldskb) - + (oth->doff << 2)); + tcph->ack = 1; + } + + tcph->rst = 1; + tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr, + niph->daddr, 0); + nskb->ip_summed = CHECKSUM_PARTIAL; + nskb->csum_start = (unsigned char *)tcph - nskb->head; + nskb->csum_offset = offsetof(struct tcphdr, check); + + /* ip_route_me_harder expects skb->dst to be set */ + skb_dst_set_noref(nskb, skb_dst(oldskb)); + + nskb->protocol = htons(ETH_P_IP); + if (ip_route_me_harder(nskb, RTN_UNSPEC)) + goto free_nskb; + + niph->ttl = ip4_dst_hoplimit(skb_dst(nskb)); + + /* "Never happens" */ + if (nskb->len > dst_mtu(skb_dst(nskb))) + goto free_nskb; + + nf_ct_attach(nskb, oldskb); + +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) + /* If we use ip_local_out for bridged traffic, the MAC source on + * the RST will be ours, instead of the destination's. This confuses + * some routers/firewalls, and they drop the packet. So we need to + * build the eth header using the original destination's MAC as the + * source, and send the RST packet directly. + */ + if (oldskb->nf_bridge) { + struct ethhdr *oeth = eth_hdr(oldskb); + nskb->dev = oldskb->nf_bridge->physindev; + niph->tot_len = htons(nskb->len); + ip_send_check(niph); + if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol), + oeth->h_source, oeth->h_dest, nskb->len) < 0) + goto free_nskb; + dev_queue_xmit(nskb); + } else +#endif + ip_local_out(nskb); + + return; + + free_nskb: + kfree_skb(nskb); +} +EXPORT_SYMBOL_GPL(nf_send_reset); -- cgit v1.2.2 From 1109a90c01177e8f4a5fd95c5b685ad02f1fe9bb Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 1 Oct 2014 11:19:17 +0200 Subject: netfilter: use IS_ENABLED(CONFIG_BRIDGE_NETFILTER) In 34666d4 ("netfilter: bridge: move br_netfilter out of the core"), the bridge netfilter code has been modularized. Use IS_ENABLED instead of ifdef to cover the module case. Fixes: 34666d4 ("netfilter: bridge: move br_netfilter out of the core") Signed-off-by: Pablo Neira Ayuso --- net/ipv4/ip_output.c | 2 +- net/ipv4/netfilter/ipt_REJECT.c | 2 +- net/ipv4/netfilter/nf_defrag_ipv4.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index c8fa62476461..e35b71289156 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -516,7 +516,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) hlen = iph->ihl * 4; mtu = mtu - hlen; /* Size of data space */ -#ifdef CONFIG_BRIDGE_NETFILTER +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) if (skb->nf_bridge) mtu -= nf_bridge_mtu_reduction(skb); #endif diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c index 5b6e0df4ccff..8f48f5517e33 100644 --- a/net/ipv4/netfilter/ipt_REJECT.c +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -20,7 +20,7 @@ #include #include #include -#ifdef CONFIG_BRIDGE_NETFILTER +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) #include #endif diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c index 76bd1aef257f..7e5ca6f2d0cd 100644 --- a/net/ipv4/netfilter/nf_defrag_ipv4.c +++ b/net/ipv4/netfilter/nf_defrag_ipv4.c @@ -50,7 +50,7 @@ static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum, zone = nf_ct_zone((struct nf_conn *)skb->nfct); #endif -#ifdef CONFIG_BRIDGE_NETFILTER +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) if (skb->nf_bridge && skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING) return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone; -- cgit v1.2.2 From 8da4cc1b10c1aeba090d1d862b17174e4dbd50a4 Mon Sep 17 00:00:00 2001 From: Arturo Borrero Date: Fri, 3 Oct 2014 14:13:36 +0200 Subject: netfilter: nft_masq: register/unregister notifiers on module init/exit We have to register the notifiers in the masquerade expression from the the module _init and _exit path. This fixes crashes when removing the masquerade rule with no ipt_MASQUERADE support in place (which was masking the problem). Fixes: 9ba1f72 ("netfilter: nf_tables: add new nft_masq expression") Signed-off-by: Arturo Borrero Gonzalez Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nft_masq_ipv4.c | 34 +++++++++++----------------------- 1 file changed, 11 insertions(+), 23 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/nft_masq_ipv4.c b/net/ipv4/netfilter/nft_masq_ipv4.c index 6ea1d207b6a5..1c636d6b5b50 100644 --- a/net/ipv4/netfilter/nft_masq_ipv4.c +++ b/net/ipv4/netfilter/nft_masq_ipv4.c @@ -32,33 +32,12 @@ static void nft_masq_ipv4_eval(const struct nft_expr *expr, data[NFT_REG_VERDICT].verdict = verdict; } -static int nft_masq_ipv4_init(const struct nft_ctx *ctx, - const struct nft_expr *expr, - const struct nlattr * const tb[]) -{ - int err; - - err = nft_masq_init(ctx, expr, tb); - if (err < 0) - return err; - - nf_nat_masquerade_ipv4_register_notifier(); - return 0; -} - -static void nft_masq_ipv4_destroy(const struct nft_ctx *ctx, - const struct nft_expr *expr) -{ - nf_nat_masquerade_ipv4_unregister_notifier(); -} - static struct nft_expr_type nft_masq_ipv4_type; static const struct nft_expr_ops nft_masq_ipv4_ops = { .type = &nft_masq_ipv4_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_masq)), .eval = nft_masq_ipv4_eval, - .init = nft_masq_ipv4_init, - .destroy = nft_masq_ipv4_destroy, + .init = nft_masq_init, .dump = nft_masq_dump, }; @@ -73,12 +52,21 @@ static struct nft_expr_type nft_masq_ipv4_type __read_mostly = { static int __init nft_masq_ipv4_module_init(void) { - return nft_register_expr(&nft_masq_ipv4_type); + int ret; + + ret = nft_register_expr(&nft_masq_ipv4_type); + if (ret < 0) + return ret; + + nf_nat_masquerade_ipv4_register_notifier(); + + return ret; } static void __exit nft_masq_ipv4_module_exit(void) { nft_unregister_expr(&nft_masq_ipv4_type); + nf_nat_masquerade_ipv4_unregister_notifier(); } module_init(nft_masq_ipv4_module_init); -- cgit v1.2.2