From 554ced0a6e2946562c20d9fffdbaf2aa7da36b1b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?M=C3=A1t=C3=A9=20Eckl?= Date: Mon, 28 May 2018 09:15:33 +0200 Subject: [PATCH] netfilter: nf_tables: add support for native socket matching MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Now it can only match the transparent flag of an ip/ipv6 socket. Signed-off-by: Máté Eckl Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nf_tables.h | 25 ++++ net/netfilter/Kconfig | 9 ++ net/netfilter/Makefile | 1 + net/netfilter/nft_socket.c | 143 +++++++++++++++++++++++ 4 files changed, 178 insertions(+) create mode 100644 net/netfilter/nft_socket.c diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 9c71f024f9cc46..3d46c82a5ebd00 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -904,6 +904,31 @@ enum nft_rt_attributes { }; #define NFTA_RT_MAX (__NFTA_RT_MAX - 1) +/** + * enum nft_socket_attributes - nf_tables socket expression netlink attributes + * + * @NFTA_SOCKET_KEY: socket key to match + * @NFTA_SOCKET_DREG: destination register + */ +enum nft_socket_attributes { + NFTA_SOCKET_UNSPEC, + NFTA_SOCKET_KEY, + NFTA_SOCKET_DREG, + __NFTA_SOCKET_MAX +}; +#define NFTA_SOCKET_MAX (__NFTA_SOCKET_MAX - 1) + +/* + * enum nft_socket_keys - nf_tables socket expression keys + * + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_ + */ +enum nft_socket_keys { + NFT_SOCKET_TRANSPARENT, + __NFT_SOCKET_MAX +}; +#define NFT_SOCKET_MAX (__NFT_SOCKET_MAX - 1) + /** * enum nft_ct_keys - nf_tables ct expression keys * diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 3ec8886850b22d..276e1e32f44ee6 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -613,6 +613,15 @@ config NFT_FIB_INET The lookup will be delegated to the IPv4 or IPv6 FIB depending on the protocol of the packet. +config NFT_SOCKET + tristate "Netfilter nf_tables socket match support" + depends on IPV6 || IPV6=n + select NF_SOCKET_IPV4 + select NF_SOCKET_IPV6 if IPV6 + help + This option allows matching for the presence or absence of a + corresponding socket and its attributes. + if NF_TABLES_NETDEV config NF_DUP_NETDEV diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 9b3434360d4963..eec169555731cd 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -102,6 +102,7 @@ obj-$(CONFIG_NFT_FIB) += nft_fib.o obj-$(CONFIG_NFT_FIB_INET) += nft_fib_inet.o obj-$(CONFIG_NFT_FIB_NETDEV) += nft_fib_netdev.o obj-$(CONFIG_NF_OSF) += nf_osf.o +obj-$(CONFIG_NFT_SOCKET) += nft_socket.o # nf_tables netdev obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c new file mode 100644 index 00000000000000..d86337068ecbe8 --- /dev/null +++ b/net/netfilter/nft_socket.c @@ -0,0 +1,143 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include +#include +#include +#include +#include + +struct nft_socket { + enum nft_socket_keys key:8; + union { + enum nft_registers dreg:8; + }; +}; + +static void nft_socket_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_socket *priv = nft_expr_priv(expr); + struct sk_buff *skb = pkt->skb; + struct sock *sk = skb->sk; + u32 *dest = ®s->data[priv->dreg]; + + if (!sk) + switch(nft_pf(pkt)) { + case NFPROTO_IPV4: + sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt)); + break; +#if IS_ENABLED(CONFIG_NF_SOCKET_IPV6) + case NFPROTO_IPV6: + sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt)); + break; +#endif + default: + WARN_ON_ONCE(1); + regs->verdict.code = NFT_BREAK; + return; + } + + if(!sk) { + nft_reg_store8(dest, 0); + return; + } + + /* So that subsequent socket matching not to require other lookups. */ + skb->sk = sk; + + switch(priv->key) { + case NFT_SOCKET_TRANSPARENT: + nft_reg_store8(dest, nf_sk_is_transparent(sk)); + break; + default: + WARN_ON(1); + regs->verdict.code = NFT_BREAK; + } +} + +static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = { + [NFTA_SOCKET_KEY] = { .type = NLA_U32 }, + [NFTA_SOCKET_DREG] = { .type = NLA_U32 }, +}; + +static int nft_socket_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_socket *priv = nft_expr_priv(expr); + unsigned int len; + + if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY]) + return -EINVAL; + + switch(ctx->family) { + case NFPROTO_IPV4: +#if IS_ENABLED(CONFIG_NF_SOCKET_IPV6) + case NFPROTO_IPV6: +#endif + case NFPROTO_INET: + break; + default: + return -EOPNOTSUPP; + } + + priv->key = ntohl(nla_get_u32(tb[NFTA_SOCKET_KEY])); + switch(priv->key) { + case NFT_SOCKET_TRANSPARENT: + len = sizeof(u8); + break; + default: + return -EOPNOTSUPP; + } + + priv->dreg = nft_parse_register(tb[NFTA_SOCKET_DREG]); + return nft_validate_register_store(ctx, priv->dreg, NULL, + NFT_DATA_VALUE, len); +} + +static int nft_socket_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_socket *priv = nft_expr_priv(expr); + + if (nla_put_u32(skb, NFTA_SOCKET_KEY, htonl(priv->key))) + return -1; + if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg)) + return -1; + return 0; +} + +static struct nft_expr_type nft_socket_type; +static const struct nft_expr_ops nft_socket_ops = { + .type = &nft_socket_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_socket)), + .eval = nft_socket_eval, + .init = nft_socket_init, + .dump = nft_socket_dump, +}; + +static struct nft_expr_type nft_socket_type __read_mostly = { + .name = "socket", + .ops = &nft_socket_ops, + .policy = nft_socket_policy, + .maxattr = NFTA_SOCKET_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_socket_module_init(void) +{ + return nft_register_expr(&nft_socket_type); +} + +static void __exit nft_socket_module_exit(void) +{ + nft_unregister_expr(&nft_socket_type); +} + +module_init(nft_socket_module_init); +module_exit(nft_socket_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Máté Eckl"); +MODULE_DESCRIPTION("nf_tables socket match module");