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
__nft_trace_packet(struct nft_traceinfo * info,const struct nft_chain * chain,enum nft_trace_types type)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 if (!info->trace || !info->nf_trace)
29 return;
30
31 info->chain = chain;
32 info->type = type;
33
34 nft_trace_notify(info);
35 }
36
nft_trace_packet(const struct nft_pktinfo * pkt,struct nft_traceinfo * info,const struct nft_chain * chain,const struct nft_rule_dp * rule,enum nft_trace_types type)37 static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
38 struct nft_traceinfo *info,
39 const struct nft_chain *chain,
40 const struct nft_rule_dp *rule,
41 enum nft_trace_types type)
42 {
43 if (static_branch_unlikely(&nft_trace_enabled)) {
44 info->nf_trace = pkt->skb->nf_trace;
45 info->rule = rule;
46 __nft_trace_packet(info, chain, type);
47 }
48 }
49
nft_trace_copy_nftrace(const struct nft_pktinfo * pkt,struct nft_traceinfo * info)50 static inline void nft_trace_copy_nftrace(const struct nft_pktinfo *pkt,
51 struct nft_traceinfo *info)
52 {
53 if (static_branch_unlikely(&nft_trace_enabled)) {
54 if (info->trace)
55 info->nf_trace = pkt->skb->nf_trace;
56 }
57 }
58
nft_bitwise_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)59 static void nft_bitwise_fast_eval(const struct nft_expr *expr,
60 struct nft_regs *regs)
61 {
62 const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
63 u32 *src = ®s->data[priv->sreg];
64 u32 *dst = ®s->data[priv->dreg];
65
66 *dst = (*src & priv->mask) ^ priv->xor;
67 }
68
nft_cmp_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)69 static void nft_cmp_fast_eval(const struct nft_expr *expr,
70 struct nft_regs *regs)
71 {
72 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
73
74 if (((regs->data[priv->sreg] & priv->mask) == priv->data) ^ priv->inv)
75 return;
76 regs->verdict.code = NFT_BREAK;
77 }
78
nft_cmp16_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)79 static void nft_cmp16_fast_eval(const struct nft_expr *expr,
80 struct nft_regs *regs)
81 {
82 const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
83 const u64 *reg_data = (const u64 *)®s->data[priv->sreg];
84 const u64 *mask = (const u64 *)&priv->mask;
85 const u64 *data = (const u64 *)&priv->data;
86
87 if (((reg_data[0] & mask[0]) == data[0] &&
88 ((reg_data[1] & mask[1]) == data[1])) ^ priv->inv)
89 return;
90 regs->verdict.code = NFT_BREAK;
91 }
92
__nft_trace_verdict(struct nft_traceinfo * info,const struct nft_chain * chain,const struct nft_regs * regs)93 static noinline void __nft_trace_verdict(struct nft_traceinfo *info,
94 const struct nft_chain *chain,
95 const struct nft_regs *regs)
96 {
97 enum nft_trace_types type;
98
99 switch (regs->verdict.code) {
100 case NFT_CONTINUE:
101 case NFT_RETURN:
102 type = NFT_TRACETYPE_RETURN;
103 break;
104 case NF_STOLEN:
105 type = NFT_TRACETYPE_RULE;
106 /* can't access skb->nf_trace; use copy */
107 break;
108 default:
109 type = NFT_TRACETYPE_RULE;
110
111 if (info->trace)
112 info->nf_trace = info->pkt->skb->nf_trace;
113 break;
114 }
115
116 __nft_trace_packet(info, chain, type);
117 }
118
nft_trace_verdict(struct nft_traceinfo * info,const struct nft_chain * chain,const struct nft_rule_dp * rule,const struct nft_regs * regs)119 static inline void nft_trace_verdict(struct nft_traceinfo *info,
120 const struct nft_chain *chain,
121 const struct nft_rule_dp *rule,
122 const struct nft_regs *regs)
123 {
124 if (static_branch_unlikely(&nft_trace_enabled)) {
125 info->rule = rule;
126 __nft_trace_verdict(info, chain, regs);
127 }
128 }
129
nft_payload_fast_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)130 static bool nft_payload_fast_eval(const struct nft_expr *expr,
131 struct nft_regs *regs,
132 const struct nft_pktinfo *pkt)
133 {
134 const struct nft_payload *priv = nft_expr_priv(expr);
135 const struct sk_buff *skb = pkt->skb;
136 u32 *dest = ®s->data[priv->dreg];
137 unsigned char *ptr;
138
139 if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
140 ptr = skb_network_header(skb);
141 else {
142 if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
143 return false;
144 ptr = skb_network_header(skb) + nft_thoff(pkt);
145 }
146
147 ptr += priv->offset;
148
149 if (unlikely(ptr + priv->len > skb_tail_pointer(skb)))
150 return false;
151
152 *dest = 0;
153 if (priv->len == 2)
154 *(u16 *)dest = *(u16 *)ptr;
155 else if (priv->len == 4)
156 *(u32 *)dest = *(u32 *)ptr;
157 else
158 *(u8 *)dest = *(u8 *)ptr;
159 return true;
160 }
161
162 DEFINE_STATIC_KEY_FALSE(nft_counters_enabled);
163
nft_update_chain_stats(const struct nft_chain * chain,const struct nft_pktinfo * pkt)164 static noinline void nft_update_chain_stats(const struct nft_chain *chain,
165 const struct nft_pktinfo *pkt)
166 {
167 struct nft_base_chain *base_chain;
168 struct nft_stats __percpu *pstats;
169 struct nft_stats *stats;
170
171 base_chain = nft_base_chain(chain);
172
173 pstats = READ_ONCE(base_chain->stats);
174 if (pstats) {
175 local_bh_disable();
176 stats = this_cpu_ptr(pstats);
177 u64_stats_update_begin(&stats->syncp);
178 stats->pkts++;
179 stats->bytes += pkt->skb->len;
180 u64_stats_update_end(&stats->syncp);
181 local_bh_enable();
182 }
183 }
184
185 struct nft_jumpstack {
186 const struct nft_chain *chain;
187 const struct nft_rule_dp *rule;
188 const struct nft_rule_dp *last_rule;
189 };
190
expr_call_ops_eval(const struct nft_expr * expr,struct nft_regs * regs,struct nft_pktinfo * pkt)191 static void expr_call_ops_eval(const struct nft_expr *expr,
192 struct nft_regs *regs,
193 struct nft_pktinfo *pkt)
194 {
195 #ifdef CONFIG_RETPOLINE
196 unsigned long e = (unsigned long)expr->ops->eval;
197 #define X(e, fun) \
198 do { if ((e) == (unsigned long)(fun)) \
199 return fun(expr, regs, pkt); } while (0)
200
201 X(e, nft_payload_eval);
202 X(e, nft_cmp_eval);
203 X(e, nft_counter_eval);
204 X(e, nft_meta_get_eval);
205 X(e, nft_lookup_eval);
206 X(e, nft_range_eval);
207 X(e, nft_immediate_eval);
208 X(e, nft_byteorder_eval);
209 X(e, nft_dynset_eval);
210 X(e, nft_rt_get_eval);
211 X(e, nft_bitwise_eval);
212 #undef X
213 #endif /* CONFIG_RETPOLINE */
214 expr->ops->eval(expr, regs, pkt);
215 }
216
217 #define nft_rule_expr_first(rule) (struct nft_expr *)&rule->data[0]
218 #define nft_rule_expr_next(expr) ((void *)expr) + expr->ops->size
219 #define nft_rule_expr_last(rule) (struct nft_expr *)&rule->data[rule->dlen]
220 #define nft_rule_next(rule) (void *)rule + sizeof(*rule) + rule->dlen
221
222 #define nft_rule_dp_for_each_expr(expr, last, rule) \
223 for ((expr) = nft_rule_expr_first(rule), (last) = nft_rule_expr_last(rule); \
224 (expr) != (last); \
225 (expr) = nft_rule_expr_next(expr))
226
227 unsigned int
nft_do_chain(struct nft_pktinfo * pkt,void * priv)228 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
229 {
230 const struct nft_chain *chain = priv, *basechain = chain;
231 const struct nft_rule_dp *rule, *last_rule;
232 const struct net *net = nft_net(pkt);
233 const struct nft_expr *expr, *last;
234 struct nft_regs regs = {};
235 unsigned int stackptr = 0;
236 struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
237 bool genbit = READ_ONCE(net->nft.gencursor);
238 struct nft_rule_blob *blob;
239 struct nft_traceinfo info;
240
241 info.trace = false;
242 if (static_branch_unlikely(&nft_trace_enabled))
243 nft_trace_init(&info, pkt, ®s.verdict, basechain);
244 do_chain:
245 if (genbit)
246 blob = rcu_dereference(chain->blob_gen_1);
247 else
248 blob = rcu_dereference(chain->blob_gen_0);
249
250 rule = (struct nft_rule_dp *)blob->data;
251 last_rule = (void *)blob->data + blob->size;
252 next_rule:
253 regs.verdict.code = NFT_CONTINUE;
254 for (; rule < last_rule; rule = nft_rule_next(rule)) {
255 nft_rule_dp_for_each_expr(expr, last, rule) {
256 if (expr->ops == &nft_cmp_fast_ops)
257 nft_cmp_fast_eval(expr, ®s);
258 else if (expr->ops == &nft_cmp16_fast_ops)
259 nft_cmp16_fast_eval(expr, ®s);
260 else if (expr->ops == &nft_bitwise_fast_ops)
261 nft_bitwise_fast_eval(expr, ®s);
262 else if (expr->ops != &nft_payload_fast_ops ||
263 !nft_payload_fast_eval(expr, ®s, pkt))
264 expr_call_ops_eval(expr, ®s, pkt);
265
266 if (regs.verdict.code != NFT_CONTINUE)
267 break;
268 }
269
270 switch (regs.verdict.code) {
271 case NFT_BREAK:
272 regs.verdict.code = NFT_CONTINUE;
273 nft_trace_copy_nftrace(pkt, &info);
274 continue;
275 case NFT_CONTINUE:
276 nft_trace_packet(pkt, &info, chain, rule,
277 NFT_TRACETYPE_RULE);
278 continue;
279 }
280 break;
281 }
282
283 nft_trace_verdict(&info, chain, rule, ®s);
284
285 switch (regs.verdict.code & NF_VERDICT_MASK) {
286 case NF_ACCEPT:
287 case NF_DROP:
288 case NF_QUEUE:
289 case NF_STOLEN:
290 return regs.verdict.code;
291 }
292
293 switch (regs.verdict.code) {
294 case NFT_JUMP:
295 if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
296 return NF_DROP;
297 jumpstack[stackptr].chain = chain;
298 jumpstack[stackptr].rule = nft_rule_next(rule);
299 jumpstack[stackptr].last_rule = last_rule;
300 stackptr++;
301 fallthrough;
302 case NFT_GOTO:
303 chain = regs.verdict.chain;
304 goto do_chain;
305 case NFT_CONTINUE:
306 case NFT_RETURN:
307 break;
308 default:
309 WARN_ON_ONCE(1);
310 }
311
312 if (stackptr > 0) {
313 stackptr--;
314 chain = jumpstack[stackptr].chain;
315 rule = jumpstack[stackptr].rule;
316 last_rule = jumpstack[stackptr].last_rule;
317 goto next_rule;
318 }
319
320 nft_trace_packet(pkt, &info, basechain, NULL, NFT_TRACETYPE_POLICY);
321
322 if (static_branch_unlikely(&nft_counters_enabled))
323 nft_update_chain_stats(basechain, pkt);
324
325 return nft_base_chain(basechain)->policy;
326 }
327 EXPORT_SYMBOL_GPL(nft_do_chain);
328
329 static struct nft_expr_type *nft_basic_types[] = {
330 &nft_imm_type,
331 &nft_cmp_type,
332 &nft_lookup_type,
333 &nft_bitwise_type,
334 &nft_byteorder_type,
335 &nft_payload_type,
336 &nft_dynset_type,
337 &nft_range_type,
338 &nft_meta_type,
339 &nft_rt_type,
340 &nft_exthdr_type,
341 &nft_last_type,
342 &nft_counter_type,
343 };
344
345 static struct nft_object_type *nft_basic_objects[] = {
346 #ifdef CONFIG_NETWORK_SECMARK
347 &nft_secmark_obj_type,
348 #endif
349 &nft_counter_obj_type,
350 };
351
nf_tables_core_module_init(void)352 int __init nf_tables_core_module_init(void)
353 {
354 int err, i, j = 0;
355
356 nft_counter_init_seqcount();
357
358 for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) {
359 err = nft_register_obj(nft_basic_objects[i]);
360 if (err)
361 goto err;
362 }
363
364 for (j = 0; j < ARRAY_SIZE(nft_basic_types); j++) {
365 err = nft_register_expr(nft_basic_types[j]);
366 if (err)
367 goto err;
368 }
369
370 return 0;
371
372 err:
373 while (j-- > 0)
374 nft_unregister_expr(nft_basic_types[j]);
375
376 while (i-- > 0)
377 nft_unregister_obj(nft_basic_objects[i]);
378
379 return err;
380 }
381
nf_tables_core_module_exit(void)382 void nf_tables_core_module_exit(void)
383 {
384 int i;
385
386 i = ARRAY_SIZE(nft_basic_types);
387 while (i-- > 0)
388 nft_unregister_expr(nft_basic_types[i]);
389
390 i = ARRAY_SIZE(nft_basic_objects);
391 while (i-- > 0)
392 nft_unregister_obj(nft_basic_objects[i]);
393 }
394