1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
4  *
5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/list.h>
11 #include <linux/rbtree.h>
12 #include <linux/netlink.h>
13 #include <linux/netfilter.h>
14 #include <linux/netfilter/nf_tables.h>
15 #include <net/netfilter/nf_tables.h>
16 #include <net/netfilter/nf_tables_core.h>
17 
18 struct nft_lookup {
19 	struct nft_set			*set;
20 	u8				sreg;
21 	u8				dreg;
22 	bool				dreg_set;
23 	bool				invert;
24 	struct nft_set_binding		binding;
25 };
26 
27 #ifdef CONFIG_MITIGATION_RETPOLINE
28 bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
29 		       const u32 *key, const struct nft_set_ext **ext)
30 {
31 	if (set->ops == &nft_set_hash_fast_type.ops)
32 		return nft_hash_lookup_fast(net, set, key, ext);
33 	if (set->ops == &nft_set_hash_type.ops)
34 		return nft_hash_lookup(net, set, key, ext);
35 
36 	if (set->ops == &nft_set_rhash_type.ops)
37 		return nft_rhash_lookup(net, set, key, ext);
38 
39 	if (set->ops == &nft_set_bitmap_type.ops)
40 		return nft_bitmap_lookup(net, set, key, ext);
41 
42 	if (set->ops == &nft_set_pipapo_type.ops)
43 		return nft_pipapo_lookup(net, set, key, ext);
44 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
45 	if (set->ops == &nft_set_pipapo_avx2_type.ops)
46 		return nft_pipapo_avx2_lookup(net, set, key, ext);
47 #endif
48 
49 	if (set->ops == &nft_set_rbtree_type.ops)
50 		return nft_rbtree_lookup(net, set, key, ext);
51 
52 	WARN_ON_ONCE(1);
53 	return set->ops->lookup(net, set, key, ext);
54 }
55 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
56 #endif
57 
58 void nft_lookup_eval(const struct nft_expr *expr,
59 		     struct nft_regs *regs,
60 		     const struct nft_pktinfo *pkt)
61 {
62 	const struct nft_lookup *priv = nft_expr_priv(expr);
63 	const struct nft_set *set = priv->set;
64 	const struct nft_set_ext *ext = NULL;
65 	const struct net *net = nft_net(pkt);
66 	bool found;
67 
68 	found =	nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
69 				  priv->invert;
70 	if (!found) {
71 		ext = nft_set_catchall_lookup(net, set);
72 		if (!ext) {
73 			regs->verdict.code = NFT_BREAK;
74 			return;
75 		}
76 	}
77 
78 	if (ext) {
79 		if (priv->dreg_set)
80 			nft_data_copy(&regs->data[priv->dreg],
81 				      nft_set_ext_data(ext), set->dlen);
82 
83 		nft_set_elem_update_expr(ext, regs, pkt);
84 	}
85 }
86 
87 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
88 	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
89 				    .len = NFT_SET_MAXNAMELEN - 1 },
90 	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
91 	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
92 	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
93 	[NFTA_LOOKUP_FLAGS]	=
94 		NLA_POLICY_MASK(NLA_BE32, NFT_LOOKUP_F_INV),
95 };
96 
97 static int nft_lookup_init(const struct nft_ctx *ctx,
98 			   const struct nft_expr *expr,
99 			   const struct nlattr * const tb[])
100 {
101 	struct nft_lookup *priv = nft_expr_priv(expr);
102 	u8 genmask = nft_genmask_next(ctx->net);
103 	struct nft_set *set;
104 	u32 flags;
105 	int err;
106 
107 	if (tb[NFTA_LOOKUP_SET] == NULL ||
108 	    tb[NFTA_LOOKUP_SREG] == NULL)
109 		return -EINVAL;
110 
111 	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
112 				    tb[NFTA_LOOKUP_SET_ID], genmask);
113 	if (IS_ERR(set))
114 		return PTR_ERR(set);
115 
116 	err = nft_parse_register_load(ctx, tb[NFTA_LOOKUP_SREG], &priv->sreg,
117 				      set->klen);
118 	if (err < 0)
119 		return err;
120 
121 	if (tb[NFTA_LOOKUP_FLAGS]) {
122 		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
123 
124 		if (flags & NFT_LOOKUP_F_INV)
125 			priv->invert = true;
126 	}
127 
128 	if (tb[NFTA_LOOKUP_DREG] != NULL) {
129 		if (priv->invert)
130 			return -EINVAL;
131 		if (!(set->flags & NFT_SET_MAP))
132 			return -EINVAL;
133 
134 		err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
135 					       &priv->dreg, NULL,
136 					       nft_set_datatype(set),
137 					       set->dlen);
138 		if (err < 0)
139 			return err;
140 		priv->dreg_set = true;
141 	} else if (set->flags & NFT_SET_MAP) {
142 		/* Map given, but user asks for lookup only (i.e. to
143 		 * ignore value assoicated with key).
144 		 *
145 		 * This makes no sense for anonymous maps since they are
146 		 * scoped to the rule, but for named sets this can be useful.
147 		 */
148 		if (set->flags & NFT_SET_ANONYMOUS)
149 			return -EINVAL;
150 	}
151 
152 	priv->binding.flags = set->flags & NFT_SET_MAP;
153 
154 	err = nf_tables_bind_set(ctx, set, &priv->binding);
155 	if (err < 0)
156 		return err;
157 
158 	priv->set = set;
159 	return 0;
160 }
161 
162 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
163 				  const struct nft_expr *expr,
164 				  enum nft_trans_phase phase)
165 {
166 	struct nft_lookup *priv = nft_expr_priv(expr);
167 
168 	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
169 }
170 
171 static void nft_lookup_activate(const struct nft_ctx *ctx,
172 				const struct nft_expr *expr)
173 {
174 	struct nft_lookup *priv = nft_expr_priv(expr);
175 
176 	nf_tables_activate_set(ctx, priv->set);
177 }
178 
179 static void nft_lookup_destroy(const struct nft_ctx *ctx,
180 			       const struct nft_expr *expr)
181 {
182 	struct nft_lookup *priv = nft_expr_priv(expr);
183 
184 	nf_tables_destroy_set(ctx, priv->set);
185 }
186 
187 static int nft_lookup_dump(struct sk_buff *skb,
188 			   const struct nft_expr *expr, bool reset)
189 {
190 	const struct nft_lookup *priv = nft_expr_priv(expr);
191 	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
192 
193 	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
194 		goto nla_put_failure;
195 	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
196 		goto nla_put_failure;
197 	if (priv->dreg_set)
198 		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
199 			goto nla_put_failure;
200 	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
201 		goto nla_put_failure;
202 	return 0;
203 
204 nla_put_failure:
205 	return -1;
206 }
207 
208 static int nft_lookup_validate(const struct nft_ctx *ctx,
209 			       const struct nft_expr *expr)
210 {
211 	const struct nft_lookup *priv = nft_expr_priv(expr);
212 	struct nft_set_iter iter;
213 
214 	if (!(priv->set->flags & NFT_SET_MAP) ||
215 	    priv->set->dtype != NFT_DATA_VERDICT)
216 		return 0;
217 
218 	iter.genmask	= nft_genmask_next(ctx->net);
219 	iter.type	= NFT_ITER_UPDATE;
220 	iter.skip	= 0;
221 	iter.count	= 0;
222 	iter.err	= 0;
223 	iter.fn		= nft_setelem_validate;
224 
225 	priv->set->ops->walk(ctx, priv->set, &iter);
226 	if (!iter.err)
227 		iter.err = nft_set_catchall_validate(ctx, priv->set);
228 
229 	if (iter.err < 0)
230 		return iter.err;
231 
232 	return 0;
233 }
234 
235 static bool nft_lookup_reduce(struct nft_regs_track *track,
236 			      const struct nft_expr *expr)
237 {
238 	const struct nft_lookup *priv = nft_expr_priv(expr);
239 
240 	if (priv->set->flags & NFT_SET_MAP)
241 		nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);
242 
243 	return false;
244 }
245 
246 static const struct nft_expr_ops nft_lookup_ops = {
247 	.type		= &nft_lookup_type,
248 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
249 	.eval		= nft_lookup_eval,
250 	.init		= nft_lookup_init,
251 	.activate	= nft_lookup_activate,
252 	.deactivate	= nft_lookup_deactivate,
253 	.destroy	= nft_lookup_destroy,
254 	.dump		= nft_lookup_dump,
255 	.validate	= nft_lookup_validate,
256 	.reduce		= nft_lookup_reduce,
257 };
258 
259 struct nft_expr_type nft_lookup_type __read_mostly = {
260 	.name		= "lookup",
261 	.ops		= &nft_lookup_ops,
262 	.policy		= nft_lookup_policy,
263 	.maxattr	= NFTA_LOOKUP_MAX,
264 	.owner		= THIS_MODULE,
265 };
266