From ed6c4136f1571bd6ab362afc3410905a8a69ca42 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 26 May 2015 18:41:40 +0200 Subject: [PATCH] netfilter: nf_tables: add netdev table to filter from ingress This allows us to create netdev tables that contain ingress chains. Use skb_header_pointer() as we may see shared sk_buffs at this stage. This change provides access to the existing nf_tables features from the ingress hook. Signed-off-by: Pablo Neira Ayuso --- include/net/netns/nftables.h | 1 + net/netfilter/Kconfig | 5 + net/netfilter/Makefile | 1 + net/netfilter/nf_tables_netdev.c | 183 +++++++++++++++++++++++++++++++ 4 files changed, 190 insertions(+) create mode 100644 net/netfilter/nf_tables_netdev.c diff --git a/include/net/netns/nftables.h b/include/net/netns/nftables.h index eee608b12cc9..c80781146019 100644 --- a/include/net/netns/nftables.h +++ b/include/net/netns/nftables.h @@ -13,6 +13,7 @@ struct netns_nftables { struct nft_af_info *inet; struct nft_af_info *arp; struct nft_af_info *bridge; + struct nft_af_info *netdev; unsigned int base_seq; u8 gencursor; }; diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 9a89e7c67d78..bd5aaebaa9a2 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -456,6 +456,11 @@ config NF_TABLES_INET help This option enables support for a mixed IPv4/IPv6 "inet" table. +config NF_TABLES_NETDEV + tristate "Netfilter nf_tables netdev tables support" + help + This option enables support for the "netdev" table. + config NFT_EXTHDR tristate "Netfilter nf_tables IPv6 exthdr module" help diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index a87d8b8ec730..70d026d46fe7 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -75,6 +75,7 @@ nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o obj-$(CONFIG_NF_TABLES) += nf_tables.o obj-$(CONFIG_NF_TABLES_INET) += nf_tables_inet.o +obj-$(CONFIG_NF_TABLES_NETDEV) += nf_tables_netdev.o obj-$(CONFIG_NFT_COMPAT) += nft_compat.o obj-$(CONFIG_NFT_EXTHDR) += nft_exthdr.o obj-$(CONFIG_NFT_META) += nft_meta.o diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c new file mode 100644 index 000000000000..04cb17057f46 --- /dev/null +++ b/net/netfilter/nf_tables_netdev.c @@ -0,0 +1,183 @@ +/* + * Copyright (c) 2015 Pablo Neira Ayuso + * + * 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 +#include +#include + +static inline void +nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt, + const struct nf_hook_ops *ops, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct iphdr *iph, _iph; + u32 len, thoff; + + nft_set_pktinfo(pkt, ops, skb, state); + + iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph), + &_iph); + if (!iph) + return; + + iph = ip_hdr(skb); + if (iph->ihl < 5 || iph->version != 4) + return; + + len = ntohs(iph->tot_len); + thoff = iph->ihl * 4; + if (skb->len < len) + return; + else if (len < thoff) + return; + + pkt->tprot = iph->protocol; + pkt->xt.thoff = thoff; + pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET; +} + +static inline void +__nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt, + const struct nf_hook_ops *ops, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ +#if IS_ENABLED(CONFIG_IPV6) + struct ipv6hdr *ip6h, _ip6h; + unsigned int thoff = 0; + unsigned short frag_off; + int protohdr; + u32 pkt_len; + + ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h), + &_ip6h); + if (!ip6h) + return; + + if (ip6h->version != 6) + return; + + pkt_len = ntohs(ip6h->payload_len); + if (pkt_len + sizeof(*ip6h) > skb->len) + return; + + protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL); + if (protohdr < 0) + return; + + pkt->tprot = protohdr; + pkt->xt.thoff = thoff; + pkt->xt.fragoff = frag_off; +#endif +} + +static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt, + const struct nf_hook_ops *ops, + struct sk_buff *skb, + const struct nf_hook_state *state) +{ + nft_set_pktinfo(pkt, ops, skb, state); + __nft_netdev_set_pktinfo_ipv6(pkt, ops, skb, state); +} + +static unsigned int +nft_do_chain_netdev(const struct nf_hook_ops *ops, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct nft_pktinfo pkt; + + switch (eth_hdr(skb)->h_proto) { + case htons(ETH_P_IP): + nft_netdev_set_pktinfo_ipv4(&pkt, ops, skb, state); + break; + case htons(ETH_P_IPV6): + nft_netdev_set_pktinfo_ipv6(&pkt, ops, skb, state); + break; + default: + nft_set_pktinfo(&pkt, ops, skb, state); + break; + } + + return nft_do_chain(&pkt, ops); +} + +static struct nft_af_info nft_af_netdev __read_mostly = { + .family = NFPROTO_NETDEV, + .nhooks = NF_NETDEV_NUMHOOKS, + .owner = THIS_MODULE, + .flags = NFT_AF_NEEDS_DEV, + .nops = 1, + .hooks = { + [NF_NETDEV_INGRESS] = nft_do_chain_netdev, + }, +}; + +static int nf_tables_netdev_init_net(struct net *net) +{ + net->nft.netdev = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL); + if (net->nft.netdev == NULL) + return -ENOMEM; + + memcpy(net->nft.netdev, &nft_af_netdev, sizeof(nft_af_netdev)); + + if (nft_register_afinfo(net, net->nft.netdev) < 0) + goto err; + + return 0; +err: + kfree(net->nft.netdev); + return -ENOMEM; +} + +static void nf_tables_netdev_exit_net(struct net *net) +{ + nft_unregister_afinfo(net->nft.netdev); + kfree(net->nft.netdev); +} + +static struct pernet_operations nf_tables_netdev_net_ops = { + .init = nf_tables_netdev_init_net, + .exit = nf_tables_netdev_exit_net, +}; + +static const struct nf_chain_type nft_filter_chain_netdev = { + .name = "filter", + .type = NFT_CHAIN_T_DEFAULT, + .family = NFPROTO_NETDEV, + .owner = THIS_MODULE, + .hook_mask = (1 << NF_NETDEV_INGRESS), +}; + +static int __init nf_tables_netdev_init(void) +{ + int ret; + + nft_register_chain_type(&nft_filter_chain_netdev); + ret = register_pernet_subsys(&nf_tables_netdev_net_ops); + if (ret < 0) + nft_unregister_chain_type(&nft_filter_chain_netdev); + + return ret; +} + +static void __exit nf_tables_netdev_exit(void) +{ + unregister_pernet_subsys(&nf_tables_netdev_net_ops); + nft_unregister_chain_type(&nft_filter_chain_netdev); +} + +module_init(nf_tables_netdev_init); +module_exit(nf_tables_netdev_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso "); +MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */ -- 2.20.1