summaryrefslogtreecommitdiff
path: root/net/netfilter/nft_xfrm.c
blob: 06d5cabf1d7c4f3adbbe6a8d5a76d597277e1af4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Generic part shared by ipv4 and ipv6 backends.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <linux/in.h>
#include <net/xfrm.h>

static const struct nla_policy nft_xfrm_policy[NFTA_XFRM_MAX + 1] = {
	[NFTA_XFRM_KEY]		= { .type = NLA_U32 },
	[NFTA_XFRM_DIR]		= { .type = NLA_U8 },
	[NFTA_XFRM_SPNUM]	= { .type = NLA_U32 },
	[NFTA_XFRM_DREG]	= { .type = NLA_U32 },
};

struct nft_xfrm {
	enum nft_xfrm_keys	key:8;
	enum nft_registers	dreg:8;
	u8			dir;
	u8			spnum;
};

static int nft_xfrm_get_init(const struct nft_ctx *ctx,
			     const struct nft_expr *expr,
			     const struct nlattr * const tb[])
{
	struct nft_xfrm *priv = nft_expr_priv(expr);
	unsigned int len = 0;
	u32 spnum = 0;
	u8 dir;

	if (!tb[NFTA_XFRM_KEY] || !tb[NFTA_XFRM_DIR] || !tb[NFTA_XFRM_DREG])
		return -EINVAL;

	switch (ctx->family) {
	case NFPROTO_IPV4:
	case NFPROTO_IPV6:
	case NFPROTO_INET:
		break;
	default:
		return -EOPNOTSUPP;
	}

	priv->key = ntohl(nla_get_u32(tb[NFTA_XFRM_KEY]));
	switch (priv->key) {
	case NFT_XFRM_KEY_REQID:
	case NFT_XFRM_KEY_SPI:
		len = sizeof(u32);
		break;
	case NFT_XFRM_KEY_DADDR_IP4:
	case NFT_XFRM_KEY_SADDR_IP4:
		len = sizeof(struct in_addr);
		break;
	case NFT_XFRM_KEY_DADDR_IP6:
	case NFT_XFRM_KEY_SADDR_IP6:
		len = sizeof(struct in6_addr);
		break;
	default:
		return -EINVAL;
	}

	dir = nla_get_u8(tb[NFTA_XFRM_DIR]);
	switch (dir) {
	case XFRM_POLICY_IN:
	case XFRM_POLICY_OUT:
		priv->dir = dir;
		break;
	default:
		return -EINVAL;
	}

	if (tb[NFTA_XFRM_SPNUM])
		spnum = ntohl(nla_get_be32(tb[NFTA_XFRM_SPNUM]));

	if (spnum >= XFRM_MAX_DEPTH)
		return -ERANGE;

	priv->spnum = spnum;

	priv->dreg = nft_parse_register(tb[NFTA_XFRM_DREG]);
	return nft_validate_register_store(ctx, priv->dreg, NULL,
					   NFT_DATA_VALUE, len);
}

/* Return true if key asks for daddr/saddr and current
 * state does have a valid address (BEET, TUNNEL).
 */
static bool xfrm_state_addr_ok(enum nft_xfrm_keys k, u8 family, u8 mode)
{
	switch (k) {
	case NFT_XFRM_KEY_DADDR_IP4:
	case NFT_XFRM_KEY_SADDR_IP4:
		if (family == NFPROTO_IPV4)
			break;
		return false;
	case NFT_XFRM_KEY_DADDR_IP6:
	case NFT_XFRM_KEY_SADDR_IP6:
		if (family == NFPROTO_IPV6)
			break;
		return false;
	default:
		return true;
	}

	return mode == XFRM_MODE_BEET || mode == XFRM_MODE_TUNNEL;
}

static void nft_xfrm_state_get_key(const struct nft_xfrm *priv,
				   struct nft_regs *regs,
				   const struct xfrm_state *state)
{
	u32 *dest = &regs->data[priv->dreg];

	if (!xfrm_state_addr_ok(priv->key,
				state->props.family,
				state->props.mode)) {
		regs->verdict.code = NFT_BREAK;
		return;
	}

	switch (priv->key) {
	case NFT_XFRM_KEY_UNSPEC:
	case __NFT_XFRM_KEY_MAX:
		WARN_ON_ONCE(1);
		break;
	case NFT_XFRM_KEY_DADDR_IP4:
		*dest = state->id.daddr.a4;
		return;
	case NFT_XFRM_KEY_DADDR_IP6:
		memcpy(dest, &state->id.daddr.in6, sizeof(struct in6_addr));
		return;
	case NFT_XFRM_KEY_SADDR_IP4:
		*dest = state->props.saddr.a4;
		return;
	case NFT_XFRM_KEY_SADDR_IP6:
		memcpy(dest, &state->props.saddr.in6, sizeof(struct in6_addr));
		return;
	case NFT_XFRM_KEY_REQID:
		*dest = state->props.reqid;
		return;
	case NFT_XFRM_KEY_SPI:
		*dest = state->id.spi;
		return;
	}

	regs->verdict.code = NFT_BREAK;
}

static void nft_xfrm_get_eval_in(const struct nft_xfrm *priv,
				    struct nft_regs *regs,
				    const struct nft_pktinfo *pkt)
{
	const struct sec_path *sp = skb_sec_path(pkt->skb);
	const struct xfrm_state *state;

	if (sp == NULL || sp->len <= priv->spnum) {
		regs->verdict.code = NFT_BREAK;
		return;
	}

	state = sp->xvec[priv->spnum];
	nft_xfrm_state_get_key(priv, regs, state);
}

static void nft_xfrm_get_eval_out(const struct nft_xfrm *priv,
				  struct nft_regs *regs,
				  const struct nft_pktinfo *pkt)
{
	const struct dst_entry *dst = skb_dst(pkt->skb);
	int i;

	for (i = 0; dst && dst->xfrm;
	     dst = ((const struct xfrm_dst *)dst)->child, i++) {
		if (i < priv->spnum)
			continue;

		nft_xfrm_state_get_key(priv, regs, dst->xfrm);
		return;
	}

	regs->verdict.code = NFT_BREAK;
}

static void nft_xfrm_get_eval(const struct nft_expr *expr,
			      struct nft_regs *regs,
			      const struct nft_pktinfo *pkt)
{
	const struct nft_xfrm *priv = nft_expr_priv(expr);

	switch (priv->dir) {
	case XFRM_POLICY_IN:
		nft_xfrm_get_eval_in(priv, regs, pkt);
		break;
	case XFRM_POLICY_OUT:
		nft_xfrm_get_eval_out(priv, regs, pkt);
		break;
	default:
		WARN_ON_ONCE(1);
		regs->verdict.code = NFT_BREAK;
		break;
	}
}

static int nft_xfrm_get_dump(struct sk_buff *skb,
			     const struct nft_expr *expr)
{
	const struct nft_xfrm *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_XFRM_DREG, priv->dreg))
		return -1;

	if (nla_put_be32(skb, NFTA_XFRM_KEY, htonl(priv->key)))
		return -1;
	if (nla_put_u8(skb, NFTA_XFRM_DIR, priv->dir))
		return -1;
	if (nla_put_be32(skb, NFTA_XFRM_SPNUM, htonl(priv->spnum)))
		return -1;

	return 0;
}

static int nft_xfrm_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
			     const struct nft_data **data)
{
	const struct nft_xfrm *priv = nft_expr_priv(expr);
	unsigned int hooks;

	switch (priv->dir) {
	case XFRM_POLICY_IN:
		hooks = (1 << NF_INET_FORWARD) |
			(1 << NF_INET_LOCAL_IN) |
			(1 << NF_INET_PRE_ROUTING);
		break;
	case XFRM_POLICY_OUT:
		hooks = (1 << NF_INET_FORWARD) |
			(1 << NF_INET_LOCAL_OUT) |
			(1 << NF_INET_POST_ROUTING);
		break;
	default:
		WARN_ON_ONCE(1);
		return -EINVAL;
	}

	return nft_chain_validate_hooks(ctx->chain, hooks);
}


static struct nft_expr_type nft_xfrm_type;
static const struct nft_expr_ops nft_xfrm_get_ops = {
	.type		= &nft_xfrm_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_xfrm)),
	.eval		= nft_xfrm_get_eval,
	.init		= nft_xfrm_get_init,
	.dump		= nft_xfrm_get_dump,
	.validate	= nft_xfrm_validate,
};

static struct nft_expr_type nft_xfrm_type __read_mostly = {
	.name		= "xfrm",
	.ops		= &nft_xfrm_get_ops,
	.policy		= nft_xfrm_policy,
	.maxattr	= NFTA_XFRM_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_xfrm_module_init(void)
{
	return nft_register_expr(&nft_xfrm_type);
}

static void __exit nft_xfrm_module_exit(void)
{
	nft_unregister_expr(&nft_xfrm_type);
}

module_init(nft_xfrm_module_init);
module_exit(nft_xfrm_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("nf_tables: xfrm/IPSec matching");
MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
MODULE_AUTHOR("Máté Eckl <ecklm94@gmail.com>");
MODULE_ALIAS_NFT_EXPR("xfrm");