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 #if defined(CONFIG_MITIGATION_RETPOLINE) && defined(CONFIG_X86)
25
26 static struct static_key_false nf_tables_skip_direct_calls;
27
nf_skip_indirect_calls(void)28 static bool nf_skip_indirect_calls(void)
29 {
30 return static_branch_likely(&nf_tables_skip_direct_calls);
31 }
32
nf_skip_indirect_calls_enable(void)33 static void __init nf_skip_indirect_calls_enable(void)
34 {
35 if (!cpu_feature_enabled(X86_FEATURE_RETPOLINE))
36 static_branch_enable(&nf_tables_skip_direct_calls);
37 }
38 #else
nf_skip_indirect_calls(void)39 static inline bool nf_skip_indirect_calls(void) { return false; }
40
nf_skip_indirect_calls_enable(void)41 static inline void nf_skip_indirect_calls_enable(void) { }
42 #endif
43
__nft_trace_packet(const struct nft_pktinfo * pkt,const struct nft_verdict * verdict,const struct nft_rule_dp * rule,struct nft_traceinfo * info,enum nft_trace_types type)44 static noinline void __nft_trace_packet(const struct nft_pktinfo *pkt,
45 const struct nft_verdict *verdict,
46 const struct nft_rule_dp *rule,
47 struct nft_traceinfo *info,
48 enum nft_trace_types type)
49 {
50 if (!info->trace || !info->nf_trace)
51 return;
52
53 info->type = type;
54
55 nft_trace_notify(pkt, verdict, rule, info);
56 }
57
nft_trace_packet(const struct nft_pktinfo * pkt,struct nft_verdict * verdict,struct nft_traceinfo * info,const struct nft_rule_dp * rule,enum nft_trace_types type)58 static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
59 struct nft_verdict *verdict,
60 struct nft_traceinfo *info,
61 const struct nft_rule_dp *rule,
62 enum nft_trace_types type)
63 {
64 if (static_branch_unlikely(&nft_trace_enabled)) {
65 info->nf_trace = pkt->skb->nf_trace;
66 __nft_trace_packet(pkt, verdict, rule, info, type);
67 }
68 }
69
nft_trace_copy_nftrace(const struct nft_pktinfo * pkt,struct nft_traceinfo * info)70 static inline void nft_trace_copy_nftrace(const struct nft_pktinfo *pkt,
71 struct nft_traceinfo *info)
72 {
73 if (static_branch_unlikely(&nft_trace_enabled))
74 info->nf_trace = pkt->skb->nf_trace;
75 }
76
nft_bitwise_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)77 static void nft_bitwise_fast_eval(const struct nft_expr *expr,
78 struct nft_regs *regs)
79 {
80 const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
81 u32 *src = ®s->data[priv->sreg];
82 u32 *dst = ®s->data[priv->dreg];
83
84 *dst = (*src & priv->mask) ^ priv->xor;
85 }
86
nft_cmp_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)87 static void nft_cmp_fast_eval(const struct nft_expr *expr,
88 struct nft_regs *regs)
89 {
90 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
91
92 if (((regs->data[priv->sreg] & priv->mask) == priv->data) ^ priv->inv)
93 return;
94 regs->verdict.code = NFT_BREAK;
95 }
96
nft_cmp16_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)97 static void nft_cmp16_fast_eval(const struct nft_expr *expr,
98 struct nft_regs *regs)
99 {
100 const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
101 const u64 *reg_data = (const u64 *)®s->data[priv->sreg];
102 const u64 *mask = (const u64 *)&priv->mask;
103 const u64 *data = (const u64 *)&priv->data;
104
105 if (((reg_data[0] & mask[0]) == data[0] &&
106 ((reg_data[1] & mask[1]) == data[1])) ^ priv->inv)
107 return;
108 regs->verdict.code = NFT_BREAK;
109 }
110
__nft_trace_verdict(const struct nft_pktinfo * pkt,struct nft_traceinfo * info,const struct nft_rule_dp * rule,const struct nft_regs * regs)111 static noinline void __nft_trace_verdict(const struct nft_pktinfo *pkt,
112 struct nft_traceinfo *info,
113 const struct nft_rule_dp *rule,
114 const struct nft_regs *regs)
115 {
116 enum nft_trace_types type;
117
118 switch (regs->verdict.code & NF_VERDICT_MASK) {
119 case NFT_CONTINUE:
120 case NFT_RETURN:
121 type = NFT_TRACETYPE_RETURN;
122 break;
123 case NF_STOLEN:
124 type = NFT_TRACETYPE_RULE;
125 /* can't access skb->nf_trace; use copy */
126 break;
127 default:
128 type = NFT_TRACETYPE_RULE;
129
130 if (info->trace)
131 info->nf_trace = pkt->skb->nf_trace;
132 break;
133 }
134
135 __nft_trace_packet(pkt, ®s->verdict, rule, info, type);
136 }
137
nft_trace_verdict(const struct nft_pktinfo * pkt,struct nft_traceinfo * info,const struct nft_rule_dp * rule,const struct nft_regs * regs)138 static inline void nft_trace_verdict(const struct nft_pktinfo *pkt,
139 struct nft_traceinfo *info,
140 const struct nft_rule_dp *rule,
141 const struct nft_regs *regs)
142 {
143 if (static_branch_unlikely(&nft_trace_enabled))
144 __nft_trace_verdict(pkt, info, rule, regs);
145 }
146
nft_payload_fast_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)147 static bool nft_payload_fast_eval(const struct nft_expr *expr,
148 struct nft_regs *regs,
149 const struct nft_pktinfo *pkt)
150 {
151 const struct nft_payload *priv = nft_expr_priv(expr);
152 const struct sk_buff *skb = pkt->skb;
153 u32 *dest = ®s->data[priv->dreg];
154 unsigned char *ptr;
155
156 if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
157 ptr = skb_network_header(skb);
158 else {
159 if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
160 return false;
161 ptr = skb->data + nft_thoff(pkt);
162 }
163
164 ptr += priv->offset;
165
166 if (unlikely(ptr + priv->len > skb_tail_pointer(skb)))
167 return false;
168
169 *dest = 0;
170 if (priv->len == 2)
171 *(u16 *)dest = *(u16 *)ptr;
172 else if (priv->len == 4)
173 *(u32 *)dest = *(u32 *)ptr;
174 else
175 *(u8 *)dest = *(u8 *)ptr;
176 return true;
177 }
178
179 DEFINE_STATIC_KEY_FALSE(nft_counters_enabled);
180
nft_update_chain_stats(const struct nft_chain * chain,const struct nft_pktinfo * pkt)181 static noinline void nft_update_chain_stats(const struct nft_chain *chain,
182 const struct nft_pktinfo *pkt)
183 {
184 struct nft_base_chain *base_chain;
185 struct nft_stats __percpu *pstats;
186 struct nft_stats *stats;
187
188 base_chain = nft_base_chain(chain);
189
190 pstats = READ_ONCE(base_chain->stats);
191 if (pstats) {
192 local_bh_disable();
193 stats = this_cpu_ptr(pstats);
194 u64_stats_update_begin(&stats->syncp);
195 stats->pkts++;
196 stats->bytes += pkt->skb->len;
197 u64_stats_update_end(&stats->syncp);
198 local_bh_enable();
199 }
200 }
201
202 struct nft_jumpstack {
203 const struct nft_rule_dp *rule;
204 };
205
expr_call_ops_eval(const struct nft_expr * expr,struct nft_regs * regs,struct nft_pktinfo * pkt)206 static void expr_call_ops_eval(const struct nft_expr *expr,
207 struct nft_regs *regs,
208 struct nft_pktinfo *pkt)
209 {
210 #ifdef CONFIG_MITIGATION_RETPOLINE
211 unsigned long e;
212
213 if (nf_skip_indirect_calls())
214 goto indirect_call;
215
216 e = (unsigned long)expr->ops->eval;
217 #define X(e, fun) \
218 do { if ((e) == (unsigned long)(fun)) \
219 return fun(expr, regs, pkt); } while (0)
220
221 X(e, nft_payload_eval);
222 X(e, nft_cmp_eval);
223 X(e, nft_counter_eval);
224 X(e, nft_meta_get_eval);
225 X(e, nft_lookup_eval);
226 #if IS_ENABLED(CONFIG_NFT_CT)
227 X(e, nft_ct_get_fast_eval);
228 #endif
229 X(e, nft_range_eval);
230 X(e, nft_immediate_eval);
231 X(e, nft_byteorder_eval);
232 X(e, nft_dynset_eval);
233 X(e, nft_rt_get_eval);
234 X(e, nft_bitwise_eval);
235 X(e, nft_objref_eval);
236 X(e, nft_objref_map_eval);
237 #undef X
238 indirect_call:
239 #endif /* CONFIG_MITIGATION_RETPOLINE */
240 expr->ops->eval(expr, regs, pkt);
241 }
242
243 #define nft_rule_expr_first(rule) (struct nft_expr *)&rule->data[0]
244 #define nft_rule_expr_next(expr) ((void *)expr) + expr->ops->size
245 #define nft_rule_expr_last(rule) (struct nft_expr *)&rule->data[rule->dlen]
246
247 #define nft_rule_dp_for_each_expr(expr, last, rule) \
248 for ((expr) = nft_rule_expr_first(rule), (last) = nft_rule_expr_last(rule); \
249 (expr) != (last); \
250 (expr) = nft_rule_expr_next(expr))
251
252 unsigned int
nft_do_chain(struct nft_pktinfo * pkt,void * priv)253 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
254 {
255 const struct nft_chain *chain = priv, *basechain = chain;
256 const struct net *net = nft_net(pkt);
257 const struct nft_expr *expr, *last;
258 const struct nft_rule_dp *rule;
259 struct nft_regs regs;
260 unsigned int stackptr = 0;
261 struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
262 bool genbit = READ_ONCE(net->nft.gencursor);
263 struct nft_rule_blob *blob;
264 struct nft_traceinfo info;
265
266 info.trace = false;
267 if (static_branch_unlikely(&nft_trace_enabled))
268 nft_trace_init(&info, pkt, basechain);
269 do_chain:
270 if (genbit)
271 blob = rcu_dereference(chain->blob_gen_1);
272 else
273 blob = rcu_dereference(chain->blob_gen_0);
274
275 rule = (struct nft_rule_dp *)blob->data;
276 next_rule:
277 regs.verdict.code = NFT_CONTINUE;
278 for (; !rule->is_last ; rule = nft_rule_next(rule)) {
279 nft_rule_dp_for_each_expr(expr, last, rule) {
280 if (expr->ops == &nft_cmp_fast_ops)
281 nft_cmp_fast_eval(expr, ®s);
282 else if (expr->ops == &nft_cmp16_fast_ops)
283 nft_cmp16_fast_eval(expr, ®s);
284 else if (expr->ops == &nft_bitwise_fast_ops)
285 nft_bitwise_fast_eval(expr, ®s);
286 else if (expr->ops != &nft_payload_fast_ops ||
287 !nft_payload_fast_eval(expr, ®s, pkt))
288 expr_call_ops_eval(expr, ®s, pkt);
289
290 if (regs.verdict.code != NFT_CONTINUE)
291 break;
292 }
293
294 switch (regs.verdict.code) {
295 case NFT_BREAK:
296 regs.verdict.code = NFT_CONTINUE;
297 nft_trace_copy_nftrace(pkt, &info);
298 continue;
299 case NFT_CONTINUE:
300 nft_trace_packet(pkt, ®s.verdict, &info, rule,
301 NFT_TRACETYPE_RULE);
302 continue;
303 }
304 break;
305 }
306
307 nft_trace_verdict(pkt, &info, rule, ®s);
308
309 switch (regs.verdict.code & NF_VERDICT_MASK) {
310 case NF_ACCEPT:
311 case NF_QUEUE:
312 case NF_STOLEN:
313 return regs.verdict.code;
314 case NF_DROP:
315 return NF_DROP_REASON(pkt->skb, SKB_DROP_REASON_NETFILTER_DROP, EPERM);
316 }
317
318 switch (regs.verdict.code) {
319 case NFT_JUMP:
320 if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
321 return NF_DROP;
322 jumpstack[stackptr].rule = nft_rule_next(rule);
323 stackptr++;
324 fallthrough;
325 case NFT_GOTO:
326 chain = regs.verdict.chain;
327 goto do_chain;
328 case NFT_CONTINUE:
329 case NFT_RETURN:
330 break;
331 default:
332 WARN_ON_ONCE(1);
333 }
334
335 if (stackptr > 0) {
336 stackptr--;
337 rule = jumpstack[stackptr].rule;
338 goto next_rule;
339 }
340
341 nft_trace_packet(pkt, ®s.verdict, &info, NULL, NFT_TRACETYPE_POLICY);
342
343 if (static_branch_unlikely(&nft_counters_enabled))
344 nft_update_chain_stats(basechain, pkt);
345
346 if (nft_base_chain(basechain)->policy == NF_DROP)
347 return NF_DROP_REASON(pkt->skb, SKB_DROP_REASON_NETFILTER_DROP, EPERM);
348
349 return nft_base_chain(basechain)->policy;
350 }
351 EXPORT_SYMBOL_GPL(nft_do_chain);
352
353 static struct nft_expr_type *nft_basic_types[] = {
354 &nft_imm_type,
355 &nft_cmp_type,
356 &nft_lookup_type,
357 &nft_bitwise_type,
358 &nft_byteorder_type,
359 &nft_payload_type,
360 &nft_dynset_type,
361 &nft_range_type,
362 &nft_meta_type,
363 &nft_rt_type,
364 &nft_exthdr_type,
365 &nft_last_type,
366 &nft_counter_type,
367 &nft_objref_type,
368 &nft_inner_type,
369 };
370
371 static struct nft_object_type *nft_basic_objects[] = {
372 #ifdef CONFIG_NETWORK_SECMARK
373 &nft_secmark_obj_type,
374 #endif
375 &nft_counter_obj_type,
376 };
377
nf_tables_core_module_init(void)378 int __init nf_tables_core_module_init(void)
379 {
380 int err, i, j = 0;
381
382 nft_counter_init_seqcount();
383
384 for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) {
385 err = nft_register_obj(nft_basic_objects[i]);
386 if (err)
387 goto err;
388 }
389
390 for (j = 0; j < ARRAY_SIZE(nft_basic_types); j++) {
391 err = nft_register_expr(nft_basic_types[j]);
392 if (err)
393 goto err;
394 }
395
396 nf_skip_indirect_calls_enable();
397
398 return 0;
399
400 err:
401 while (j-- > 0)
402 nft_unregister_expr(nft_basic_types[j]);
403
404 while (i-- > 0)
405 nft_unregister_obj(nft_basic_objects[i]);
406
407 return err;
408 }
409
nf_tables_core_module_exit(void)410 void nf_tables_core_module_exit(void)
411 {
412 int i;
413
414 i = ARRAY_SIZE(nft_basic_types);
415 while (i-- > 0)
416 nft_unregister_expr(nft_basic_types[i]);
417
418 i = ARRAY_SIZE(nft_basic_objects);
419 while (i-- > 0)
420 nft_unregister_obj(nft_basic_objects[i]);
421 }
422