1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Generic part shared by ipv4 and ipv6 backends.
5 */
6
7#include <linux/kernel.h>
8#include <linux/init.h>
9#include <linux/module.h>
10#include <linux/netlink.h>
11#include <linux/netfilter.h>
12#include <linux/netfilter/nf_tables.h>
13#include <net/netfilter/nf_tables_core.h>
14#include <net/netfilter/nf_tables.h>
15#include <linux/in.h>
16#include <net/xfrm.h>
17
18static const struct nla_policy nft_xfrm_policy[NFTA_XFRM_MAX + 1] = {
19 [NFTA_XFRM_KEY] = NLA_POLICY_MAX(NLA_BE32, 255),
20 [NFTA_XFRM_DIR] = { .type = NLA_U8 },
21 [NFTA_XFRM_SPNUM] = NLA_POLICY_MAX(NLA_BE32, 255),
22 [NFTA_XFRM_DREG] = { .type = NLA_U32 },
23};
24
25struct nft_xfrm {
26 enum nft_xfrm_keys key:8;
27 u8 dreg;
28 u8 dir;
29 u8 spnum;
30 u8 len;
31};
32
33static int nft_xfrm_get_init(const struct nft_ctx *ctx,
34 const struct nft_expr *expr,
35 const struct nlattr * const tb[])
36{
37 struct nft_xfrm *priv = nft_expr_priv(expr);
38 unsigned int len = 0;
39 u32 spnum = 0;
40 u8 dir;
41
42 if (!tb[NFTA_XFRM_KEY] || !tb[NFTA_XFRM_DIR] || !tb[NFTA_XFRM_DREG])
43 return -EINVAL;
44
45 switch (ctx->family) {
46 case NFPROTO_IPV4:
47 case NFPROTO_IPV6:
48 case NFPROTO_INET:
49 break;
50 default:
51 return -EOPNOTSUPP;
52 }
53
54 priv->key = ntohl(nla_get_be32(tb[NFTA_XFRM_KEY]));
55 switch (priv->key) {
56 case NFT_XFRM_KEY_REQID:
57 case NFT_XFRM_KEY_SPI:
58 len = sizeof(u32);
59 break;
60 case NFT_XFRM_KEY_DADDR_IP4:
61 case NFT_XFRM_KEY_SADDR_IP4:
62 len = sizeof(struct in_addr);
63 break;
64 case NFT_XFRM_KEY_DADDR_IP6:
65 case NFT_XFRM_KEY_SADDR_IP6:
66 len = sizeof(struct in6_addr);
67 break;
68 default:
69 return -EINVAL;
70 }
71
72 dir = nla_get_u8(nla: tb[NFTA_XFRM_DIR]);
73 switch (dir) {
74 case XFRM_POLICY_IN:
75 case XFRM_POLICY_OUT:
76 priv->dir = dir;
77 break;
78 default:
79 return -EINVAL;
80 }
81
82 if (tb[NFTA_XFRM_SPNUM])
83 spnum = ntohl(nla_get_be32(tb[NFTA_XFRM_SPNUM]));
84
85 if (spnum >= XFRM_MAX_DEPTH)
86 return -ERANGE;
87
88 priv->spnum = spnum;
89
90 priv->len = len;
91 return nft_parse_register_store(ctx, attr: tb[NFTA_XFRM_DREG], dreg: &priv->dreg,
92 NULL, type: NFT_DATA_VALUE, len);
93}
94
95/* Return true if key asks for daddr/saddr and current
96 * state does have a valid address (BEET, TUNNEL).
97 */
98static bool xfrm_state_addr_ok(enum nft_xfrm_keys k, u8 family, u8 mode)
99{
100 switch (k) {
101 case NFT_XFRM_KEY_DADDR_IP4:
102 case NFT_XFRM_KEY_SADDR_IP4:
103 if (family == NFPROTO_IPV4)
104 break;
105 return false;
106 case NFT_XFRM_KEY_DADDR_IP6:
107 case NFT_XFRM_KEY_SADDR_IP6:
108 if (family == NFPROTO_IPV6)
109 break;
110 return false;
111 default:
112 return true;
113 }
114
115 return mode == XFRM_MODE_BEET || mode == XFRM_MODE_TUNNEL ||
116 mode == XFRM_MODE_IPTFS;
117}
118
119static void nft_xfrm_state_get_key(const struct nft_xfrm *priv,
120 struct nft_regs *regs,
121 const struct xfrm_state *state)
122{
123 u32 *dest = &regs->data[priv->dreg];
124
125 if (!xfrm_state_addr_ok(k: priv->key,
126 family: state->props.family,
127 mode: state->props.mode)) {
128 regs->verdict.code = NFT_BREAK;
129 return;
130 }
131
132 switch (priv->key) {
133 case NFT_XFRM_KEY_UNSPEC:
134 case __NFT_XFRM_KEY_MAX:
135 WARN_ON_ONCE(1);
136 break;
137 case NFT_XFRM_KEY_DADDR_IP4:
138 *dest = (__force __u32)state->id.daddr.a4;
139 return;
140 case NFT_XFRM_KEY_DADDR_IP6:
141 memcpy(dest, &state->id.daddr.in6, sizeof(struct in6_addr));
142 return;
143 case NFT_XFRM_KEY_SADDR_IP4:
144 *dest = (__force __u32)state->props.saddr.a4;
145 return;
146 case NFT_XFRM_KEY_SADDR_IP6:
147 memcpy(dest, &state->props.saddr.in6, sizeof(struct in6_addr));
148 return;
149 case NFT_XFRM_KEY_REQID:
150 *dest = state->props.reqid;
151 return;
152 case NFT_XFRM_KEY_SPI:
153 *dest = (__force __u32)state->id.spi;
154 return;
155 }
156
157 regs->verdict.code = NFT_BREAK;
158}
159
160static void nft_xfrm_get_eval_in(const struct nft_xfrm *priv,
161 struct nft_regs *regs,
162 const struct nft_pktinfo *pkt)
163{
164 const struct sec_path *sp = skb_sec_path(skb: pkt->skb);
165 const struct xfrm_state *state;
166
167 if (sp == NULL || sp->len <= priv->spnum) {
168 regs->verdict.code = NFT_BREAK;
169 return;
170 }
171
172 state = sp->xvec[priv->spnum];
173 nft_xfrm_state_get_key(priv, regs, state);
174}
175
176static void nft_xfrm_get_eval_out(const struct nft_xfrm *priv,
177 struct nft_regs *regs,
178 const struct nft_pktinfo *pkt)
179{
180 const struct dst_entry *dst = skb_dst(skb: pkt->skb);
181 int i;
182
183 for (i = 0; dst && dst->xfrm;
184 dst = ((const struct xfrm_dst *)dst)->child, i++) {
185 if (i < priv->spnum)
186 continue;
187
188 nft_xfrm_state_get_key(priv, regs, state: dst->xfrm);
189 return;
190 }
191
192 regs->verdict.code = NFT_BREAK;
193}
194
195static void nft_xfrm_get_eval(const struct nft_expr *expr,
196 struct nft_regs *regs,
197 const struct nft_pktinfo *pkt)
198{
199 const struct nft_xfrm *priv = nft_expr_priv(expr);
200
201 switch (priv->dir) {
202 case XFRM_POLICY_IN:
203 nft_xfrm_get_eval_in(priv, regs, pkt);
204 break;
205 case XFRM_POLICY_OUT:
206 nft_xfrm_get_eval_out(priv, regs, pkt);
207 break;
208 default:
209 WARN_ON_ONCE(1);
210 regs->verdict.code = NFT_BREAK;
211 break;
212 }
213}
214
215static int nft_xfrm_get_dump(struct sk_buff *skb,
216 const struct nft_expr *expr, bool reset)
217{
218 const struct nft_xfrm *priv = nft_expr_priv(expr);
219
220 if (nft_dump_register(skb, attr: NFTA_XFRM_DREG, reg: priv->dreg))
221 return -1;
222
223 if (nla_put_be32(skb, attrtype: NFTA_XFRM_KEY, htonl(priv->key)))
224 return -1;
225 if (nla_put_u8(skb, attrtype: NFTA_XFRM_DIR, value: priv->dir))
226 return -1;
227 if (nla_put_be32(skb, attrtype: NFTA_XFRM_SPNUM, htonl(priv->spnum)))
228 return -1;
229
230 return 0;
231}
232
233static int nft_xfrm_validate(const struct nft_ctx *ctx, const struct nft_expr *expr)
234{
235 const struct nft_xfrm *priv = nft_expr_priv(expr);
236 unsigned int hooks;
237
238 if (ctx->family != NFPROTO_IPV4 &&
239 ctx->family != NFPROTO_IPV6 &&
240 ctx->family != NFPROTO_INET)
241 return -EOPNOTSUPP;
242
243 switch (priv->dir) {
244 case XFRM_POLICY_IN:
245 hooks = (1 << NF_INET_FORWARD) |
246 (1 << NF_INET_LOCAL_IN) |
247 (1 << NF_INET_PRE_ROUTING);
248 break;
249 case XFRM_POLICY_OUT:
250 hooks = (1 << NF_INET_FORWARD) |
251 (1 << NF_INET_LOCAL_OUT) |
252 (1 << NF_INET_POST_ROUTING);
253 break;
254 default:
255 WARN_ON_ONCE(1);
256 return -EINVAL;
257 }
258
259 return nft_chain_validate_hooks(chain: ctx->chain, hook_flags: hooks);
260}
261
262static bool nft_xfrm_reduce(struct nft_regs_track *track,
263 const struct nft_expr *expr)
264{
265 const struct nft_xfrm *priv = nft_expr_priv(expr);
266 const struct nft_xfrm *xfrm;
267
268 if (!nft_reg_track_cmp(track, expr, dreg: priv->dreg)) {
269 nft_reg_track_update(track, expr, dreg: priv->dreg, len: priv->len);
270 return false;
271 }
272
273 xfrm = nft_expr_priv(expr: track->regs[priv->dreg].selector);
274 if (priv->key != xfrm->key ||
275 priv->dreg != xfrm->dreg ||
276 priv->dir != xfrm->dir ||
277 priv->spnum != xfrm->spnum) {
278 nft_reg_track_update(track, expr, dreg: priv->dreg, len: priv->len);
279 return false;
280 }
281
282 if (!track->regs[priv->dreg].bitwise)
283 return true;
284
285 return nft_expr_reduce_bitwise(track, expr);
286}
287
288static struct nft_expr_type nft_xfrm_type;
289static const struct nft_expr_ops nft_xfrm_get_ops = {
290 .type = &nft_xfrm_type,
291 .size = NFT_EXPR_SIZE(sizeof(struct nft_xfrm)),
292 .eval = nft_xfrm_get_eval,
293 .init = nft_xfrm_get_init,
294 .dump = nft_xfrm_get_dump,
295 .validate = nft_xfrm_validate,
296 .reduce = nft_xfrm_reduce,
297};
298
299static struct nft_expr_type nft_xfrm_type __read_mostly = {
300 .name = "xfrm",
301 .ops = &nft_xfrm_get_ops,
302 .policy = nft_xfrm_policy,
303 .maxattr = NFTA_XFRM_MAX,
304 .owner = THIS_MODULE,
305};
306
307static int __init nft_xfrm_module_init(void)
308{
309 return nft_register_expr(&nft_xfrm_type);
310}
311
312static void __exit nft_xfrm_module_exit(void)
313{
314 nft_unregister_expr(&nft_xfrm_type);
315}
316
317module_init(nft_xfrm_module_init);
318module_exit(nft_xfrm_module_exit);
319
320MODULE_LICENSE("GPL");
321MODULE_DESCRIPTION("nf_tables: xfrm/IPSec matching");
322MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
323MODULE_AUTHOR("Máté Eckl <ecklm94@gmail.com>");
324MODULE_ALIAS_NFT_EXPR("xfrm");
325

source code of linux/net/netfilter/nft_xfrm.c