1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/module.h>
3 #include <linux/netfilter/nf_tables.h>
4 #include <net/netfilter/nf_tables.h>
5 #include <net/netfilter/nf_tables_core.h>
6 #include <net/netfilter/nf_socket.h>
7 #include <net/inet_sock.h>
8 #include <net/tcp.h>
9
10 struct nft_socket {
11 enum nft_socket_keys key:8;
12 union {
13 u8 dreg;
14 };
15 };
16
nft_socket_do_lookup(const struct nft_pktinfo * pkt)17 static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
18 {
19 const struct net_device *indev = nft_in(pkt);
20 const struct sk_buff *skb = pkt->skb;
21 struct sock *sk = NULL;
22
23 if (!indev)
24 return NULL;
25
26 switch (nft_pf(pkt)) {
27 case NFPROTO_IPV4:
28 sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);
29 break;
30 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
31 case NFPROTO_IPV6:
32 sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);
33 break;
34 #endif
35 default:
36 WARN_ON_ONCE(1);
37 break;
38 }
39
40 return sk;
41 }
42
nft_socket_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)43 static void nft_socket_eval(const struct nft_expr *expr,
44 struct nft_regs *regs,
45 const struct nft_pktinfo *pkt)
46 {
47 const struct nft_socket *priv = nft_expr_priv(expr);
48 struct sk_buff *skb = pkt->skb;
49 struct sock *sk = skb->sk;
50 u32 *dest = ®s->data[priv->dreg];
51
52 if (sk && !net_eq(nft_net(pkt), sock_net(sk)))
53 sk = NULL;
54
55 if (!sk)
56 sk = nft_socket_do_lookup(pkt);
57
58 if (!sk) {
59 regs->verdict.code = NFT_BREAK;
60 return;
61 }
62
63 switch(priv->key) {
64 case NFT_SOCKET_TRANSPARENT:
65 nft_reg_store8(dest, inet_sk_transparent(sk));
66 break;
67 case NFT_SOCKET_MARK:
68 if (sk_fullsock(sk)) {
69 *dest = sk->sk_mark;
70 } else {
71 regs->verdict.code = NFT_BREAK;
72 return;
73 }
74 break;
75 default:
76 WARN_ON(1);
77 regs->verdict.code = NFT_BREAK;
78 }
79
80 if (sk != skb->sk)
81 sock_gen_put(sk);
82 }
83
84 static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
85 [NFTA_SOCKET_KEY] = { .type = NLA_U32 },
86 [NFTA_SOCKET_DREG] = { .type = NLA_U32 },
87 };
88
nft_socket_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])89 static int nft_socket_init(const struct nft_ctx *ctx,
90 const struct nft_expr *expr,
91 const struct nlattr * const tb[])
92 {
93 struct nft_socket *priv = nft_expr_priv(expr);
94 unsigned int len;
95
96 if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
97 return -EINVAL;
98
99 switch(ctx->family) {
100 case NFPROTO_IPV4:
101 #if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
102 case NFPROTO_IPV6:
103 #endif
104 case NFPROTO_INET:
105 break;
106 default:
107 return -EOPNOTSUPP;
108 }
109
110 priv->key = ntohl(nla_get_u32(tb[NFTA_SOCKET_KEY]));
111 switch(priv->key) {
112 case NFT_SOCKET_TRANSPARENT:
113 len = sizeof(u8);
114 break;
115 case NFT_SOCKET_MARK:
116 len = sizeof(u32);
117 break;
118 default:
119 return -EOPNOTSUPP;
120 }
121
122 return nft_parse_register_store(ctx, tb[NFTA_SOCKET_DREG], &priv->dreg,
123 NULL, NFT_DATA_VALUE, len);
124 }
125
nft_socket_dump(struct sk_buff * skb,const struct nft_expr * expr)126 static int nft_socket_dump(struct sk_buff *skb,
127 const struct nft_expr *expr)
128 {
129 const struct nft_socket *priv = nft_expr_priv(expr);
130
131 if (nla_put_u32(skb, NFTA_SOCKET_KEY, htonl(priv->key)))
132 return -1;
133 if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
134 return -1;
135 return 0;
136 }
137
nft_socket_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** data)138 static int nft_socket_validate(const struct nft_ctx *ctx,
139 const struct nft_expr *expr,
140 const struct nft_data **data)
141 {
142 if (ctx->family != NFPROTO_IPV4 &&
143 ctx->family != NFPROTO_IPV6 &&
144 ctx->family != NFPROTO_INET)
145 return -EOPNOTSUPP;
146
147 return nft_chain_validate_hooks(ctx->chain,
148 (1 << NF_INET_PRE_ROUTING) |
149 (1 << NF_INET_LOCAL_IN) |
150 (1 << NF_INET_LOCAL_OUT));
151 }
152
153 static struct nft_expr_type nft_socket_type;
154 static const struct nft_expr_ops nft_socket_ops = {
155 .type = &nft_socket_type,
156 .size = NFT_EXPR_SIZE(sizeof(struct nft_socket)),
157 .eval = nft_socket_eval,
158 .init = nft_socket_init,
159 .dump = nft_socket_dump,
160 .validate = nft_socket_validate,
161 };
162
163 static struct nft_expr_type nft_socket_type __read_mostly = {
164 .name = "socket",
165 .ops = &nft_socket_ops,
166 .policy = nft_socket_policy,
167 .maxattr = NFTA_SOCKET_MAX,
168 .owner = THIS_MODULE,
169 };
170
nft_socket_module_init(void)171 static int __init nft_socket_module_init(void)
172 {
173 return nft_register_expr(&nft_socket_type);
174 }
175
nft_socket_module_exit(void)176 static void __exit nft_socket_module_exit(void)
177 {
178 nft_unregister_expr(&nft_socket_type);
179 }
180
181 module_init(nft_socket_module_init);
182 module_exit(nft_socket_module_exit);
183
184 MODULE_LICENSE("GPL");
185 MODULE_AUTHOR("Máté Eckl");
186 MODULE_DESCRIPTION("nf_tables socket match module");
187 MODULE_ALIAS_NFT_EXPR("socket");
188