1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008 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/module.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/rculist.h>
13 #include <linux/skbuff.h>
14 #include <linux/netlink.h>
15 #include <linux/netfilter.h>
16 #include <linux/static_key.h>
17 #include <linux/netfilter/nfnetlink.h>
18 #include <linux/netfilter/nf_tables.h>
19 #include <net/netfilter/nf_tables_core.h>
20 #include <net/netfilter/nf_tables.h>
21 #include <net/netfilter/nf_log.h>
22 #include <net/netfilter/nft_meta.h>
23 
24 static noinline void __nft_trace_packet(struct nft_traceinfo *info,
25 					const struct nft_chain *chain,
26 					enum nft_trace_types type)
27 {
28 	const struct nft_pktinfo *pkt = info->pkt;
29 
30 	if (!info->trace || !pkt->skb->nf_trace)
31 		return;
32 
33 	info->chain = chain;
34 	info->type = type;
35 
36 	nft_trace_notify(info);
37 }
38 
39 static inline void nft_trace_packet(struct nft_traceinfo *info,
40 				    const struct nft_chain *chain,
41 				    const struct nft_rule_dp *rule,
42 				    enum nft_trace_types type)
43 {
44 	if (static_branch_unlikely(&nft_trace_enabled)) {
45 		info->rule = rule;
46 		__nft_trace_packet(info, chain, type);
47 	}
48 }
49 
50 static void nft_bitwise_fast_eval(const struct nft_expr *expr,
51 				  struct nft_regs *regs)
52 {
53 	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
54 	u32 *src = &regs->data[priv->sreg];
55 	u32 *dst = &regs->data[priv->dreg];
56 
57 	*dst = (*src & priv->mask) ^ priv->xor;
58 }
59 
60 static void nft_cmp_fast_eval(const struct nft_expr *expr,
61 			      struct nft_regs *regs)
62 {
63 	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
64 
65 	if (((regs->data[priv->sreg] & priv->mask) == priv->data) ^ priv->inv)
66 		return;
67 	regs->verdict.code = NFT_BREAK;
68 }
69 
70 static noinline void __nft_trace_verdict(struct nft_traceinfo *info,
71 					 const struct nft_chain *chain,
72 					 const struct nft_regs *regs)
73 {
74 	enum nft_trace_types type;
75 
76 	switch (regs->verdict.code) {
77 	case NFT_CONTINUE:
78 	case NFT_RETURN:
79 		type = NFT_TRACETYPE_RETURN;
80 		break;
81 	default:
82 		type = NFT_TRACETYPE_RULE;
83 		break;
84 	}
85 
86 	__nft_trace_packet(info, chain, type);
87 }
88 
89 static inline void nft_trace_verdict(struct nft_traceinfo *info,
90 				     const struct nft_chain *chain,
91 				     const struct nft_rule_dp *rule,
92 				     const struct nft_regs *regs)
93 {
94 	if (static_branch_unlikely(&nft_trace_enabled)) {
95 		info->rule = rule;
96 		__nft_trace_verdict(info, chain, regs);
97 	}
98 }
99 
100 static bool nft_payload_fast_eval(const struct nft_expr *expr,
101 				  struct nft_regs *regs,
102 				  const struct nft_pktinfo *pkt)
103 {
104 	const struct nft_payload *priv = nft_expr_priv(expr);
105 	const struct sk_buff *skb = pkt->skb;
106 	u32 *dest = &regs->data[priv->dreg];
107 	unsigned char *ptr;
108 
109 	if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
110 		ptr = skb_network_header(skb);
111 	else {
112 		if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
113 			return false;
114 		ptr = skb_network_header(skb) + nft_thoff(pkt);
115 	}
116 
117 	ptr += priv->offset;
118 
119 	if (unlikely(ptr + priv->len > skb_tail_pointer(skb)))
120 		return false;
121 
122 	*dest = 0;
123 	if (priv->len == 2)
124 		*(u16 *)dest = *(u16 *)ptr;
125 	else if (priv->len == 4)
126 		*(u32 *)dest = *(u32 *)ptr;
127 	else
128 		*(u8 *)dest = *(u8 *)ptr;
129 	return true;
130 }
131 
132 DEFINE_STATIC_KEY_FALSE(nft_counters_enabled);
133 
134 static noinline void nft_update_chain_stats(const struct nft_chain *chain,
135 					    const struct nft_pktinfo *pkt)
136 {
137 	struct nft_base_chain *base_chain;
138 	struct nft_stats __percpu *pstats;
139 	struct nft_stats *stats;
140 
141 	base_chain = nft_base_chain(chain);
142 
143 	pstats = READ_ONCE(base_chain->stats);
144 	if (pstats) {
145 		local_bh_disable();
146 		stats = this_cpu_ptr(pstats);
147 		u64_stats_update_begin(&stats->syncp);
148 		stats->pkts++;
149 		stats->bytes += pkt->skb->len;
150 		u64_stats_update_end(&stats->syncp);
151 		local_bh_enable();
152 	}
153 }
154 
155 struct nft_jumpstack {
156 	const struct nft_chain *chain;
157 	const struct nft_rule_dp *rule;
158 	const struct nft_rule_dp *last_rule;
159 };
160 
161 static void expr_call_ops_eval(const struct nft_expr *expr,
162 			       struct nft_regs *regs,
163 			       struct nft_pktinfo *pkt)
164 {
165 #ifdef CONFIG_RETPOLINE
166 	unsigned long e = (unsigned long)expr->ops->eval;
167 #define X(e, fun) \
168 	do { if ((e) == (unsigned long)(fun)) \
169 		return fun(expr, regs, pkt); } while (0)
170 
171 	X(e, nft_payload_eval);
172 	X(e, nft_cmp_eval);
173 	X(e, nft_counter_eval);
174 	X(e, nft_meta_get_eval);
175 	X(e, nft_lookup_eval);
176 	X(e, nft_range_eval);
177 	X(e, nft_immediate_eval);
178 	X(e, nft_byteorder_eval);
179 	X(e, nft_dynset_eval);
180 	X(e, nft_rt_get_eval);
181 	X(e, nft_bitwise_eval);
182 #undef  X
183 #endif /* CONFIG_RETPOLINE */
184 	expr->ops->eval(expr, regs, pkt);
185 }
186 
187 #define nft_rule_expr_first(rule)	(struct nft_expr *)&rule->data[0]
188 #define nft_rule_expr_next(expr)	((void *)expr) + expr->ops->size
189 #define nft_rule_expr_last(rule)	(struct nft_expr *)&rule->data[rule->dlen]
190 #define nft_rule_next(rule)		(void *)rule + sizeof(*rule) + rule->dlen
191 
192 #define nft_rule_dp_for_each_expr(expr, last, rule) \
193         for ((expr) = nft_rule_expr_first(rule), (last) = nft_rule_expr_last(rule); \
194              (expr) != (last); \
195              (expr) = nft_rule_expr_next(expr))
196 
197 unsigned int
198 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
199 {
200 	const struct nft_chain *chain = priv, *basechain = chain;
201 	const struct nft_rule_dp *rule, *last_rule;
202 	const struct net *net = nft_net(pkt);
203 	const struct nft_expr *expr, *last;
204 	struct nft_regs regs;
205 	unsigned int stackptr = 0;
206 	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
207 	bool genbit = READ_ONCE(net->nft.gencursor);
208 	struct nft_rule_blob *blob;
209 	struct nft_traceinfo info;
210 
211 	info.trace = false;
212 	if (static_branch_unlikely(&nft_trace_enabled))
213 		nft_trace_init(&info, pkt, &regs.verdict, basechain);
214 do_chain:
215 	if (genbit)
216 		blob = rcu_dereference(chain->blob_gen_1);
217 	else
218 		blob = rcu_dereference(chain->blob_gen_0);
219 
220 	rule = (struct nft_rule_dp *)blob->data;
221 	last_rule = (void *)blob->data + blob->size;
222 next_rule:
223 	regs.verdict.code = NFT_CONTINUE;
224 	for (; rule < last_rule; rule = nft_rule_next(rule)) {
225 		nft_rule_dp_for_each_expr(expr, last, rule) {
226 			if (expr->ops == &nft_cmp_fast_ops)
227 				nft_cmp_fast_eval(expr, &regs);
228 			else if (expr->ops == &nft_bitwise_fast_ops)
229 				nft_bitwise_fast_eval(expr, &regs);
230 			else if (expr->ops != &nft_payload_fast_ops ||
231 				 !nft_payload_fast_eval(expr, &regs, pkt))
232 				expr_call_ops_eval(expr, &regs, pkt);
233 
234 			if (regs.verdict.code != NFT_CONTINUE)
235 				break;
236 		}
237 
238 		switch (regs.verdict.code) {
239 		case NFT_BREAK:
240 			regs.verdict.code = NFT_CONTINUE;
241 			continue;
242 		case NFT_CONTINUE:
243 			nft_trace_packet(&info, chain, rule,
244 					 NFT_TRACETYPE_RULE);
245 			continue;
246 		}
247 		break;
248 	}
249 
250 	nft_trace_verdict(&info, chain, rule, &regs);
251 
252 	switch (regs.verdict.code & NF_VERDICT_MASK) {
253 	case NF_ACCEPT:
254 	case NF_DROP:
255 	case NF_QUEUE:
256 	case NF_STOLEN:
257 		return regs.verdict.code;
258 	}
259 
260 	switch (regs.verdict.code) {
261 	case NFT_JUMP:
262 		if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
263 			return NF_DROP;
264 		jumpstack[stackptr].chain = chain;
265 		jumpstack[stackptr].rule = nft_rule_next(rule);
266 		jumpstack[stackptr].last_rule = last_rule;
267 		stackptr++;
268 		fallthrough;
269 	case NFT_GOTO:
270 		chain = regs.verdict.chain;
271 		goto do_chain;
272 	case NFT_CONTINUE:
273 	case NFT_RETURN:
274 		break;
275 	default:
276 		WARN_ON_ONCE(1);
277 	}
278 
279 	if (stackptr > 0) {
280 		stackptr--;
281 		chain = jumpstack[stackptr].chain;
282 		rule = jumpstack[stackptr].rule;
283 		last_rule = jumpstack[stackptr].last_rule;
284 		goto next_rule;
285 	}
286 
287 	nft_trace_packet(&info, basechain, NULL, NFT_TRACETYPE_POLICY);
288 
289 	if (static_branch_unlikely(&nft_counters_enabled))
290 		nft_update_chain_stats(basechain, pkt);
291 
292 	return nft_base_chain(basechain)->policy;
293 }
294 EXPORT_SYMBOL_GPL(nft_do_chain);
295 
296 static struct nft_expr_type *nft_basic_types[] = {
297 	&nft_imm_type,
298 	&nft_cmp_type,
299 	&nft_lookup_type,
300 	&nft_bitwise_type,
301 	&nft_byteorder_type,
302 	&nft_payload_type,
303 	&nft_dynset_type,
304 	&nft_range_type,
305 	&nft_meta_type,
306 	&nft_rt_type,
307 	&nft_exthdr_type,
308 	&nft_last_type,
309 	&nft_counter_type,
310 };
311 
312 static struct nft_object_type *nft_basic_objects[] = {
313 #ifdef CONFIG_NETWORK_SECMARK
314 	&nft_secmark_obj_type,
315 #endif
316 	&nft_counter_obj_type,
317 };
318 
319 int __init nf_tables_core_module_init(void)
320 {
321 	int err, i, j = 0;
322 
323 	nft_counter_init_seqcount();
324 
325 	for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) {
326 		err = nft_register_obj(nft_basic_objects[i]);
327 		if (err)
328 			goto err;
329 	}
330 
331 	for (j = 0; j < ARRAY_SIZE(nft_basic_types); j++) {
332 		err = nft_register_expr(nft_basic_types[j]);
333 		if (err)
334 			goto err;
335 	}
336 
337 	return 0;
338 
339 err:
340 	while (j-- > 0)
341 		nft_unregister_expr(nft_basic_types[j]);
342 
343 	while (i-- > 0)
344 		nft_unregister_obj(nft_basic_objects[i]);
345 
346 	return err;
347 }
348 
349 void nf_tables_core_module_exit(void)
350 {
351 	int i;
352 
353 	i = ARRAY_SIZE(nft_basic_types);
354 	while (i-- > 0)
355 		nft_unregister_expr(nft_basic_types[i]);
356 
357 	i = ARRAY_SIZE(nft_basic_objects);
358 	while (i-- > 0)
359 		nft_unregister_obj(nft_basic_objects[i]);
360 }
361