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
10struct nft_socket {
11	enum nft_socket_keys		key:8;
12	u8				level;
13	u8				len;
14	union {
15		u8			dreg;
16	};
17};
18
19static void nft_socket_wildcard(const struct nft_pktinfo *pkt,
20				struct nft_regs *regs, struct sock *sk,
21				u32 *dest)
22{
23	switch (nft_pf(pkt)) {
24	case NFPROTO_IPV4:
25		nft_reg_store8(dest, inet_sk(sk)->inet_rcv_saddr == 0);
26		break;
27#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
28	case NFPROTO_IPV6:
29		nft_reg_store8(dest, ipv6_addr_any(&sk->sk_v6_rcv_saddr));
30		break;
31#endif
32	default:
33		regs->verdict.code = NFT_BREAK;
34		return;
35	}
36}
37
38#ifdef CONFIG_SOCK_CGROUP_DATA
39static noinline bool
40nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo *pkt, u32 level)
41{
42	struct cgroup *cgrp;
43	u64 cgid;
44
45	if (!sk_fullsock(sk))
46		return false;
47
48	cgrp = cgroup_ancestor(sock_cgroup_ptr(&sk->sk_cgrp_data), level);
49	if (!cgrp)
50		return false;
51
52	cgid = cgroup_id(cgrp);
53	memcpy(dest, &cgid, sizeof(u64));
54	return true;
55}
56#endif
57
58static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
59{
60	const struct net_device *indev = nft_in(pkt);
61	const struct sk_buff *skb = pkt->skb;
62	struct sock *sk = NULL;
63
64	if (!indev)
65		return NULL;
66
67	switch (nft_pf(pkt)) {
68	case NFPROTO_IPV4:
69		sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);
70		break;
71#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
72	case NFPROTO_IPV6:
73		sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);
74		break;
75#endif
76	default:
77		WARN_ON_ONCE(1);
78		break;
79	}
80
81	return sk;
82}
83
84static void nft_socket_eval(const struct nft_expr *expr,
85			    struct nft_regs *regs,
86			    const struct nft_pktinfo *pkt)
87{
88	const struct nft_socket *priv = nft_expr_priv(expr);
89	struct sk_buff *skb = pkt->skb;
90	struct sock *sk = skb->sk;
91	u32 *dest = &regs->data[priv->dreg];
92
93	if (sk && !net_eq(nft_net(pkt), sock_net(sk)))
94		sk = NULL;
95
96	if (!sk)
97		sk = nft_socket_do_lookup(pkt);
98
99	if (!sk) {
100		regs->verdict.code = NFT_BREAK;
101		return;
102	}
103
104	switch(priv->key) {
105	case NFT_SOCKET_TRANSPARENT:
106		nft_reg_store8(dest, inet_sk_transparent(sk));
107		break;
108	case NFT_SOCKET_MARK:
109		if (sk_fullsock(sk)) {
110			*dest = READ_ONCE(sk->sk_mark);
111		} else {
112			regs->verdict.code = NFT_BREAK;
113			return;
114		}
115		break;
116	case NFT_SOCKET_WILDCARD:
117		if (!sk_fullsock(sk)) {
118			regs->verdict.code = NFT_BREAK;
119			return;
120		}
121		nft_socket_wildcard(pkt, regs, sk, dest);
122		break;
123#ifdef CONFIG_SOCK_CGROUP_DATA
124	case NFT_SOCKET_CGROUPV2:
125		if (!nft_sock_get_eval_cgroupv2(dest, sk, pkt, priv->level)) {
126			regs->verdict.code = NFT_BREAK;
127			return;
128		}
129		break;
130#endif
131	default:
132		WARN_ON(1);
133		regs->verdict.code = NFT_BREAK;
134	}
135
136	if (sk != skb->sk)
137		sock_gen_put(sk);
138}
139
140static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
141	[NFTA_SOCKET_KEY]		= NLA_POLICY_MAX(NLA_BE32, 255),
142	[NFTA_SOCKET_DREG]		= { .type = NLA_U32 },
143	[NFTA_SOCKET_LEVEL]		= NLA_POLICY_MAX(NLA_BE32, 255),
144};
145
146static int nft_socket_init(const struct nft_ctx *ctx,
147			   const struct nft_expr *expr,
148			   const struct nlattr * const tb[])
149{
150	struct nft_socket *priv = nft_expr_priv(expr);
151	unsigned int len;
152
153	if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
154		return -EINVAL;
155
156	switch(ctx->family) {
157	case NFPROTO_IPV4:
158#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
159	case NFPROTO_IPV6:
160#endif
161	case NFPROTO_INET:
162		break;
163	default:
164		return -EOPNOTSUPP;
165	}
166
167	priv->key = ntohl(nla_get_be32(tb[NFTA_SOCKET_KEY]));
168	switch(priv->key) {
169	case NFT_SOCKET_TRANSPARENT:
170	case NFT_SOCKET_WILDCARD:
171		len = sizeof(u8);
172		break;
173	case NFT_SOCKET_MARK:
174		len = sizeof(u32);
175		break;
176#ifdef CONFIG_CGROUPS
177	case NFT_SOCKET_CGROUPV2: {
178		unsigned int level;
179
180		if (!tb[NFTA_SOCKET_LEVEL])
181			return -EINVAL;
182
183		level = ntohl(nla_get_be32(tb[NFTA_SOCKET_LEVEL]));
184		if (level > 255)
185			return -EOPNOTSUPP;
186
187		priv->level = level;
188		len = sizeof(u64);
189		break;
190	}
191#endif
192	default:
193		return -EOPNOTSUPP;
194	}
195
196	priv->len = len;
197	return nft_parse_register_store(ctx, tb[NFTA_SOCKET_DREG], &priv->dreg,
198					NULL, NFT_DATA_VALUE, len);
199}
200
201static int nft_socket_dump(struct sk_buff *skb,
202			   const struct nft_expr *expr, bool reset)
203{
204	const struct nft_socket *priv = nft_expr_priv(expr);
205
206	if (nla_put_be32(skb, NFTA_SOCKET_KEY, htonl(priv->key)))
207		return -1;
208	if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
209		return -1;
210	if (priv->key == NFT_SOCKET_CGROUPV2 &&
211	    nla_put_be32(skb, NFTA_SOCKET_LEVEL, htonl(priv->level)))
212		return -1;
213	return 0;
214}
215
216static bool nft_socket_reduce(struct nft_regs_track *track,
217			      const struct nft_expr *expr)
218{
219	const struct nft_socket *priv = nft_expr_priv(expr);
220	const struct nft_socket *socket;
221
222	if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
223		nft_reg_track_update(track, expr, priv->dreg, priv->len);
224		return false;
225	}
226
227	socket = nft_expr_priv(track->regs[priv->dreg].selector);
228	if (priv->key != socket->key ||
229	    priv->dreg != socket->dreg ||
230	    priv->level != socket->level) {
231		nft_reg_track_update(track, expr, priv->dreg, priv->len);
232		return false;
233	}
234
235	if (!track->regs[priv->dreg].bitwise)
236		return true;
237
238	return nft_expr_reduce_bitwise(track, expr);
239}
240
241static int nft_socket_validate(const struct nft_ctx *ctx,
242			       const struct nft_expr *expr,
243			       const struct nft_data **data)
244{
245	if (ctx->family != NFPROTO_IPV4 &&
246	    ctx->family != NFPROTO_IPV6 &&
247	    ctx->family != NFPROTO_INET)
248		return -EOPNOTSUPP;
249
250	return nft_chain_validate_hooks(ctx->chain,
251					(1 << NF_INET_PRE_ROUTING) |
252					(1 << NF_INET_LOCAL_IN) |
253					(1 << NF_INET_LOCAL_OUT));
254}
255
256static struct nft_expr_type nft_socket_type;
257static const struct nft_expr_ops nft_socket_ops = {
258	.type		= &nft_socket_type,
259	.size		= NFT_EXPR_SIZE(sizeof(struct nft_socket)),
260	.eval		= nft_socket_eval,
261	.init		= nft_socket_init,
262	.dump		= nft_socket_dump,
263	.validate	= nft_socket_validate,
264	.reduce		= nft_socket_reduce,
265};
266
267static struct nft_expr_type nft_socket_type __read_mostly = {
268	.name		= "socket",
269	.ops		= &nft_socket_ops,
270	.policy		= nft_socket_policy,
271	.maxattr	= NFTA_SOCKET_MAX,
272	.owner		= THIS_MODULE,
273};
274
275static int __init nft_socket_module_init(void)
276{
277	return nft_register_expr(&nft_socket_type);
278}
279
280static void __exit nft_socket_module_exit(void)
281{
282	nft_unregister_expr(&nft_socket_type);
283}
284
285module_init(nft_socket_module_init);
286module_exit(nft_socket_module_exit);
287
288MODULE_LICENSE("GPL");
289MODULE_AUTHOR("M��t�� Eckl");
290MODULE_DESCRIPTION("nf_tables socket match module");
291MODULE_ALIAS_NFT_EXPR("socket");
292