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netfilter: nf_tables: add xfrm expression
supports fetching saddr/daddr of tunnel mode states, request id and spi. If direction is 'in', use inbound skb secpath, else dst->xfrm. Joint work with Máté Eckl. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal
Pablo Neira Ayuso
parent
2953d80ff0
commit
6c47260250
@ -1514,6 +1514,35 @@ enum nft_devices_attributes {
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};
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#define NFTA_DEVICE_MAX (__NFTA_DEVICE_MAX - 1)
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/*
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* enum nft_xfrm_attributes - nf_tables xfrm expr netlink attributes
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*
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* @NFTA_XFRM_DREG: destination register (NLA_U32)
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* @NFTA_XFRM_KEY: enum nft_xfrm_keys (NLA_U32)
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* @NFTA_XFRM_DIR: direction (NLA_U8)
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* @NFTA_XFRM_SPNUM: index in secpath array (NLA_U32)
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*/
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enum nft_xfrm_attributes {
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NFTA_XFRM_UNSPEC,
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NFTA_XFRM_DREG,
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NFTA_XFRM_KEY,
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NFTA_XFRM_DIR,
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NFTA_XFRM_SPNUM,
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__NFTA_XFRM_MAX
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};
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#define NFTA_XFRM_MAX (__NFTA_XFRM_MAX - 1)
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enum nft_xfrm_keys {
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NFT_XFRM_KEY_UNSPEC,
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NFT_XFRM_KEY_DADDR_IP4,
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NFT_XFRM_KEY_DADDR_IP6,
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NFT_XFRM_KEY_SADDR_IP4,
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NFT_XFRM_KEY_SADDR_IP6,
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NFT_XFRM_KEY_REQID,
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NFT_XFRM_KEY_SPI,
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__NFT_XFRM_KEY_MAX,
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};
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#define NFT_XFRM_KEY_MAX (__NFT_XFRM_KEY_MAX - 1)
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/**
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* enum nft_trace_attributes - nf_tables trace netlink attributes
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@ -625,6 +625,13 @@ config NFT_FIB_INET
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The lookup will be delegated to the IPv4 or IPv6 FIB depending
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on the protocol of the packet.
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config NFT_XFRM
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tristate "Netfilter nf_tables xfrm/IPSec security association matching"
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depends on XFRM
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help
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This option adds an expression that you can use to extract properties
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of a packets security association.
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config NFT_SOCKET
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tristate "Netfilter nf_tables socket match support"
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depends on IPV6 || IPV6=n
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@ -113,6 +113,7 @@ obj-$(CONFIG_NFT_FIB_NETDEV) += nft_fib_netdev.o
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obj-$(CONFIG_NFT_SOCKET) += nft_socket.o
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obj-$(CONFIG_NFT_OSF) += nft_osf.o
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obj-$(CONFIG_NFT_TPROXY) += nft_tproxy.o
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obj-$(CONFIG_NFT_XFRM) += nft_xfrm.o
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# nf_tables netdev
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obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o
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293
net/netfilter/nft_xfrm.c
Normal file
293
net/netfilter/nft_xfrm.c
Normal file
@ -0,0 +1,293 @@
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Generic part shared by ipv4 and ipv6 backends.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <net/netfilter/nf_tables.h>
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#include <linux/in.h>
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#include <net/xfrm.h>
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static const struct nla_policy nft_xfrm_policy[NFTA_XFRM_MAX + 1] = {
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[NFTA_XFRM_KEY] = { .type = NLA_U32 },
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[NFTA_XFRM_DIR] = { .type = NLA_U8 },
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[NFTA_XFRM_SPNUM] = { .type = NLA_U32 },
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[NFTA_XFRM_DREG] = { .type = NLA_U32 },
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};
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struct nft_xfrm {
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enum nft_xfrm_keys key:8;
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enum nft_registers dreg:8;
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u8 dir;
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u8 spnum;
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};
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static int nft_xfrm_get_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_xfrm *priv = nft_expr_priv(expr);
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unsigned int len = 0;
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u32 spnum = 0;
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u8 dir;
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if (!tb[NFTA_XFRM_KEY] || !tb[NFTA_XFRM_DIR] || !tb[NFTA_XFRM_DREG])
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return -EINVAL;
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switch (ctx->family) {
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case NFPROTO_IPV4:
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case NFPROTO_IPV6:
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case NFPROTO_INET:
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break;
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default:
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return -EOPNOTSUPP;
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}
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priv->key = ntohl(nla_get_u32(tb[NFTA_XFRM_KEY]));
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switch (priv->key) {
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case NFT_XFRM_KEY_REQID:
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case NFT_XFRM_KEY_SPI:
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len = sizeof(u32);
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break;
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case NFT_XFRM_KEY_DADDR_IP4:
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case NFT_XFRM_KEY_SADDR_IP4:
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len = sizeof(struct in_addr);
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break;
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case NFT_XFRM_KEY_DADDR_IP6:
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case NFT_XFRM_KEY_SADDR_IP6:
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len = sizeof(struct in6_addr);
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break;
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default:
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return -EINVAL;
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}
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dir = nla_get_u8(tb[NFTA_XFRM_DIR]);
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switch (dir) {
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case XFRM_POLICY_IN:
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case XFRM_POLICY_OUT:
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priv->dir = dir;
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break;
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default:
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return -EINVAL;
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}
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if (tb[NFTA_XFRM_SPNUM])
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spnum = ntohl(nla_get_be32(tb[NFTA_XFRM_SPNUM]));
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if (spnum >= XFRM_MAX_DEPTH)
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return -ERANGE;
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priv->spnum = spnum;
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priv->dreg = nft_parse_register(tb[NFTA_XFRM_DREG]);
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return nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, len);
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}
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/* Return true if key asks for daddr/saddr and current
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* state does have a valid address (BEET, TUNNEL).
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*/
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static bool xfrm_state_addr_ok(enum nft_xfrm_keys k, u8 family, u8 mode)
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{
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switch (k) {
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case NFT_XFRM_KEY_DADDR_IP4:
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case NFT_XFRM_KEY_SADDR_IP4:
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if (family == NFPROTO_IPV4)
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break;
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return false;
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case NFT_XFRM_KEY_DADDR_IP6:
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case NFT_XFRM_KEY_SADDR_IP6:
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if (family == NFPROTO_IPV6)
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break;
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return false;
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default:
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return true;
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}
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return mode == XFRM_MODE_BEET || mode == XFRM_MODE_TUNNEL;
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}
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static void nft_xfrm_state_get_key(const struct nft_xfrm *priv,
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struct nft_regs *regs,
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const struct xfrm_state *state,
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u8 family)
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{
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u32 *dest = ®s->data[priv->dreg];
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if (!xfrm_state_addr_ok(priv->key, family, state->props.mode)) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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switch (priv->key) {
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case NFT_XFRM_KEY_UNSPEC:
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case __NFT_XFRM_KEY_MAX:
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WARN_ON_ONCE(1);
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break;
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case NFT_XFRM_KEY_DADDR_IP4:
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*dest = state->id.daddr.a4;
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return;
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case NFT_XFRM_KEY_DADDR_IP6:
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memcpy(dest, &state->id.daddr.in6, sizeof(struct in6_addr));
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return;
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case NFT_XFRM_KEY_SADDR_IP4:
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*dest = state->props.saddr.a4;
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return;
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case NFT_XFRM_KEY_SADDR_IP6:
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memcpy(dest, &state->props.saddr.in6, sizeof(struct in6_addr));
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return;
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case NFT_XFRM_KEY_REQID:
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*dest = state->props.reqid;
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return;
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case NFT_XFRM_KEY_SPI:
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*dest = state->id.spi;
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return;
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}
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regs->verdict.code = NFT_BREAK;
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}
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static void nft_xfrm_get_eval_in(const struct nft_xfrm *priv,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct sec_path *sp = pkt->skb->sp;
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const struct xfrm_state *state;
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if (sp == NULL || sp->len <= priv->spnum) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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state = sp->xvec[priv->spnum];
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nft_xfrm_state_get_key(priv, regs, state, nft_pf(pkt));
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}
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static void nft_xfrm_get_eval_out(const struct nft_xfrm *priv,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct dst_entry *dst = skb_dst(pkt->skb);
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int i;
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for (i = 0; dst && dst->xfrm;
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dst = ((const struct xfrm_dst *)dst)->child, i++) {
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if (i < priv->spnum)
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continue;
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nft_xfrm_state_get_key(priv, regs, dst->xfrm, nft_pf(pkt));
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return;
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}
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regs->verdict.code = NFT_BREAK;
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}
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static void nft_xfrm_get_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_xfrm *priv = nft_expr_priv(expr);
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switch (priv->dir) {
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case XFRM_POLICY_IN:
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nft_xfrm_get_eval_in(priv, regs, pkt);
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break;
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case XFRM_POLICY_OUT:
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nft_xfrm_get_eval_out(priv, regs, pkt);
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break;
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default:
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WARN_ON_ONCE(1);
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regs->verdict.code = NFT_BREAK;
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break;
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}
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}
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static int nft_xfrm_get_dump(struct sk_buff *skb,
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const struct nft_expr *expr)
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{
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const struct nft_xfrm *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_XFRM_DREG, priv->dreg))
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return -1;
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if (nla_put_be32(skb, NFTA_XFRM_KEY, htonl(priv->key)))
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return -1;
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if (nla_put_u8(skb, NFTA_XFRM_DIR, priv->dir))
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return -1;
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if (nla_put_be32(skb, NFTA_XFRM_SPNUM, htonl(priv->spnum)))
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return -1;
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return 0;
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}
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static int nft_xfrm_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
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const struct nft_data **data)
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{
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const struct nft_xfrm *priv = nft_expr_priv(expr);
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unsigned int hooks;
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switch (priv->dir) {
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case XFRM_POLICY_IN:
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hooks = (1 << NF_INET_FORWARD) |
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(1 << NF_INET_LOCAL_IN) |
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(1 << NF_INET_PRE_ROUTING);
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break;
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case XFRM_POLICY_OUT:
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hooks = (1 << NF_INET_FORWARD) |
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(1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_POST_ROUTING);
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break;
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default:
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WARN_ON_ONCE(1);
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return -EINVAL;
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}
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return nft_chain_validate_hooks(ctx->chain, hooks);
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}
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static struct nft_expr_type nft_xfrm_type;
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static const struct nft_expr_ops nft_xfrm_get_ops = {
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.type = &nft_xfrm_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_xfrm)),
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.eval = nft_xfrm_get_eval,
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.init = nft_xfrm_get_init,
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.dump = nft_xfrm_get_dump,
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.validate = nft_xfrm_validate,
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};
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static struct nft_expr_type nft_xfrm_type __read_mostly = {
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.name = "xfrm",
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.ops = &nft_xfrm_get_ops,
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.policy = nft_xfrm_policy,
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.maxattr = NFTA_XFRM_MAX,
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.owner = THIS_MODULE,
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};
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static int __init nft_xfrm_module_init(void)
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{
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return nft_register_expr(&nft_xfrm_type);
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}
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static void __exit nft_xfrm_module_exit(void)
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{
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nft_unregister_expr(&nft_xfrm_type);
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}
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module_init(nft_xfrm_module_init);
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module_exit(nft_xfrm_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("nf_tables: xfrm/IPSec matching");
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MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
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MODULE_AUTHOR("Máté Eckl <ecklm94@gmail.com>");
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MODULE_ALIAS_NFT_EXPR("xfrm");
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