1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/netlink.h>
12 #include <linux/netfilter.h>
13 #include <linux/netfilter/nfnetlink.h>
14 #include <linux/netfilter/nf_tables.h>
15 #include <linux/netfilter/nf_tables_compat.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <linux/netfilter_ipv4/ip_tables.h>
18 #include <linux/netfilter_ipv6/ip6_tables.h>
19 #include <linux/netfilter_bridge/ebtables.h>
20 #include <linux/netfilter_arp/arp_tables.h>
21 #include <net/netfilter/nf_tables.h>
22 #include <net/netfilter/nf_log.h>
23
24 /* Used for matches where *info is larger than X byte */
25 #define NFT_MATCH_LARGE_THRESH 192
26
27 struct nft_xt_match_priv {
28 void *info;
29 };
30
nft_compat_chain_validate_dependency(const struct nft_ctx * ctx,const char * tablename)31 static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
32 const char *tablename)
33 {
34 enum nft_chain_types type = NFT_CHAIN_T_DEFAULT;
35 const struct nft_chain *chain = ctx->chain;
36 const struct nft_base_chain *basechain;
37
38 if (!tablename ||
39 !nft_is_base_chain(chain))
40 return 0;
41
42 basechain = nft_base_chain(chain);
43 if (strcmp(tablename, "nat") == 0) {
44 if (ctx->family != NFPROTO_BRIDGE)
45 type = NFT_CHAIN_T_NAT;
46 if (basechain->type->type != type)
47 return -EINVAL;
48 }
49
50 return 0;
51 }
52
53 union nft_entry {
54 struct ipt_entry e4;
55 struct ip6t_entry e6;
56 struct ebt_entry ebt;
57 struct arpt_entry arp;
58 };
59
60 static inline void
nft_compat_set_par(struct xt_action_param * par,const struct nft_pktinfo * pkt,const void * xt,const void * xt_info)61 nft_compat_set_par(struct xt_action_param *par,
62 const struct nft_pktinfo *pkt,
63 const void *xt, const void *xt_info)
64 {
65 par->state = pkt->state;
66 par->thoff = nft_thoff(pkt);
67 par->fragoff = pkt->fragoff;
68 par->target = xt;
69 par->targinfo = xt_info;
70 par->hotdrop = false;
71 }
72
nft_target_eval_xt(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)73 static void nft_target_eval_xt(const struct nft_expr *expr,
74 struct nft_regs *regs,
75 const struct nft_pktinfo *pkt)
76 {
77 void *info = nft_expr_priv(expr);
78 struct xt_target *target = expr->ops->data;
79 struct sk_buff *skb = pkt->skb;
80 struct xt_action_param xt;
81 int ret;
82
83 nft_compat_set_par(&xt, pkt, target, info);
84
85 ret = target->target(skb, &xt);
86
87 if (xt.hotdrop)
88 ret = NF_DROP;
89
90 switch (ret) {
91 case XT_CONTINUE:
92 regs->verdict.code = NFT_CONTINUE;
93 break;
94 default:
95 regs->verdict.code = ret;
96 break;
97 }
98 }
99
nft_target_eval_bridge(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)100 static void nft_target_eval_bridge(const struct nft_expr *expr,
101 struct nft_regs *regs,
102 const struct nft_pktinfo *pkt)
103 {
104 void *info = nft_expr_priv(expr);
105 struct xt_target *target = expr->ops->data;
106 struct sk_buff *skb = pkt->skb;
107 struct xt_action_param xt;
108 int ret;
109
110 nft_compat_set_par(&xt, pkt, target, info);
111
112 ret = target->target(skb, &xt);
113
114 if (xt.hotdrop)
115 ret = NF_DROP;
116
117 switch (ret) {
118 case EBT_ACCEPT:
119 regs->verdict.code = NF_ACCEPT;
120 break;
121 case EBT_DROP:
122 regs->verdict.code = NF_DROP;
123 break;
124 case EBT_CONTINUE:
125 regs->verdict.code = NFT_CONTINUE;
126 break;
127 case EBT_RETURN:
128 regs->verdict.code = NFT_RETURN;
129 break;
130 default:
131 regs->verdict.code = ret;
132 break;
133 }
134 }
135
136 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
137 [NFTA_TARGET_NAME] = { .type = NLA_NUL_STRING,
138 .len = XT_EXTENSION_MAXNAMELEN, },
139 [NFTA_TARGET_REV] = NLA_POLICY_MAX(NLA_BE32, 255),
140 [NFTA_TARGET_INFO] = { .type = NLA_BINARY },
141 };
142
143 static void
nft_target_set_tgchk_param(struct xt_tgchk_param * par,const struct nft_ctx * ctx,struct xt_target * target,void * info,union nft_entry * entry,u16 proto,bool inv)144 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
145 const struct nft_ctx *ctx,
146 struct xt_target *target, void *info,
147 union nft_entry *entry, u16 proto, bool inv)
148 {
149 par->net = ctx->net;
150 par->table = ctx->table->name;
151 switch (ctx->family) {
152 case AF_INET:
153 entry->e4.ip.proto = proto;
154 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
155 break;
156 case AF_INET6:
157 if (proto)
158 entry->e6.ipv6.flags |= IP6T_F_PROTO;
159
160 entry->e6.ipv6.proto = proto;
161 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
162 break;
163 case NFPROTO_BRIDGE:
164 entry->ebt.ethproto = (__force __be16)proto;
165 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
166 break;
167 case NFPROTO_ARP:
168 break;
169 }
170 par->entryinfo = entry;
171 par->target = target;
172 par->targinfo = info;
173 if (nft_is_base_chain(ctx->chain)) {
174 const struct nft_base_chain *basechain =
175 nft_base_chain(ctx->chain);
176 const struct nf_hook_ops *ops = &basechain->ops;
177
178 par->hook_mask = 1 << ops->hooknum;
179 } else {
180 par->hook_mask = 0;
181 }
182 par->family = ctx->family;
183 par->nft_compat = true;
184 }
185
target_compat_from_user(struct xt_target * t,void * in,void * out)186 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
187 {
188 int pad;
189
190 memcpy(out, in, t->targetsize);
191 pad = XT_ALIGN(t->targetsize) - t->targetsize;
192 if (pad > 0)
193 memset(out + t->targetsize, 0, pad);
194 }
195
196 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
197 [NFTA_RULE_COMPAT_PROTO] = { .type = NLA_U32 },
198 [NFTA_RULE_COMPAT_FLAGS] = NLA_POLICY_MASK(NLA_BE32, NFT_RULE_COMPAT_F_MASK),
199 };
200
nft_parse_compat(const struct nlattr * attr,u16 * proto,bool * inv)201 static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
202 {
203 struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
204 u32 l4proto;
205 u32 flags;
206 int err;
207
208 err = nla_parse_nested_deprecated(tb, NFTA_RULE_COMPAT_MAX, attr,
209 nft_rule_compat_policy, NULL);
210 if (err < 0)
211 return err;
212
213 if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
214 return -EINVAL;
215
216 flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
217 if (flags & NFT_RULE_COMPAT_F_UNUSED ||
218 flags & ~NFT_RULE_COMPAT_F_MASK)
219 return -EINVAL;
220 if (flags & NFT_RULE_COMPAT_F_INV)
221 *inv = true;
222
223 l4proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
224 if (l4proto > U16_MAX)
225 return -EINVAL;
226
227 *proto = l4proto;
228
229 return 0;
230 }
231
nft_compat_wait_for_destructors(struct net * net)232 static void nft_compat_wait_for_destructors(struct net *net)
233 {
234 /* xtables matches or targets can have side effects, e.g.
235 * creation/destruction of /proc files.
236 * The xt ->destroy functions are run asynchronously from
237 * work queue. If we have pending invocations we thus
238 * need to wait for those to finish.
239 */
240 nf_tables_trans_destroy_flush_work(net);
241 }
242
243 static int
nft_target_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])244 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
245 const struct nlattr * const tb[])
246 {
247 void *info = nft_expr_priv(expr);
248 struct xt_target *target = expr->ops->data;
249 struct xt_tgchk_param par;
250 size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
251 u16 proto = 0;
252 bool inv = false;
253 union nft_entry e = {};
254 int ret;
255
256 target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
257
258 if (ctx->nla[NFTA_RULE_COMPAT]) {
259 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
260 if (ret < 0)
261 return ret;
262 }
263
264 nft_compat_wait_for_destructors(ctx->net);
265
266 nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
267
268 ret = xt_check_target(&par, size, proto, inv);
269 if (ret < 0) {
270 if (ret == -ENOENT) {
271 const char *modname = NULL;
272
273 if (strcmp(target->name, "LOG") == 0)
274 modname = "nf_log_syslog";
275 else if (strcmp(target->name, "NFLOG") == 0)
276 modname = "nfnetlink_log";
277
278 if (modname &&
279 nft_request_module(ctx->net, "%s", modname) == -EAGAIN)
280 return -EAGAIN;
281 }
282
283 return ret;
284 }
285
286 /* The standard target cannot be used */
287 if (!target->target)
288 return -EINVAL;
289
290 return 0;
291 }
292
__nft_mt_tg_destroy(struct module * me,const struct nft_expr * expr)293 static void __nft_mt_tg_destroy(struct module *me, const struct nft_expr *expr)
294 {
295 module_put(me);
296 kfree(expr->ops);
297 }
298
299 static void
nft_target_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)300 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
301 {
302 struct xt_target *target = expr->ops->data;
303 void *info = nft_expr_priv(expr);
304 struct module *me = target->me;
305 struct xt_tgdtor_param par;
306
307 par.net = ctx->net;
308 par.target = target;
309 par.targinfo = info;
310 par.family = ctx->family;
311 if (par.target->destroy != NULL)
312 par.target->destroy(&par);
313
314 __nft_mt_tg_destroy(me, expr);
315 }
316
nft_extension_dump_info(struct sk_buff * skb,int attr,const void * info,unsigned int size,unsigned int user_size)317 static int nft_extension_dump_info(struct sk_buff *skb, int attr,
318 const void *info,
319 unsigned int size, unsigned int user_size)
320 {
321 unsigned int info_size, aligned_size = XT_ALIGN(size);
322 struct nlattr *nla;
323
324 nla = nla_reserve(skb, attr, aligned_size);
325 if (!nla)
326 return -1;
327
328 info_size = user_size ? : size;
329 memcpy(nla_data(nla), info, info_size);
330 memset(nla_data(nla) + info_size, 0, aligned_size - info_size);
331
332 return 0;
333 }
334
nft_target_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)335 static int nft_target_dump(struct sk_buff *skb,
336 const struct nft_expr *expr, bool reset)
337 {
338 const struct xt_target *target = expr->ops->data;
339 void *info = nft_expr_priv(expr);
340
341 if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
342 nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
343 nft_extension_dump_info(skb, NFTA_TARGET_INFO, info,
344 target->targetsize, target->usersize))
345 goto nla_put_failure;
346
347 return 0;
348
349 nla_put_failure:
350 return -1;
351 }
352
nft_target_validate(const struct nft_ctx * ctx,const struct nft_expr * expr)353 static int nft_target_validate(const struct nft_ctx *ctx,
354 const struct nft_expr *expr)
355 {
356 int ret;
357
358 if (ctx->family != NFPROTO_IPV4 &&
359 ctx->family != NFPROTO_IPV6 &&
360 ctx->family != NFPROTO_INET &&
361 ctx->family != NFPROTO_BRIDGE &&
362 ctx->family != NFPROTO_ARP)
363 return -EOPNOTSUPP;
364
365 ret = nft_chain_validate_hooks(ctx->chain,
366 (1 << NF_INET_PRE_ROUTING) |
367 (1 << NF_INET_LOCAL_IN) |
368 (1 << NF_INET_FORWARD) |
369 (1 << NF_INET_LOCAL_OUT) |
370 (1 << NF_INET_POST_ROUTING));
371 if (ret)
372 return ret;
373
374 if (nft_is_base_chain(ctx->chain)) {
375 const struct nft_base_chain *basechain =
376 nft_base_chain(ctx->chain);
377 const struct nf_hook_ops *ops = &basechain->ops;
378 unsigned int hook_mask = 1 << ops->hooknum;
379 struct xt_target *target = expr->ops->data;
380 void *info = nft_expr_priv(expr);
381 struct xt_tgchk_param par;
382 union nft_entry e = {};
383
384 if (target->hooks && !(hook_mask & target->hooks))
385 return -EINVAL;
386
387 nft_target_set_tgchk_param(&par, ctx, target, info, &e, 0, false);
388
389 ret = xt_check_hooks_target(&par);
390 if (ret < 0)
391 return ret;
392
393 ret = nft_compat_chain_validate_dependency(ctx, target->table);
394 if (ret < 0)
395 return ret;
396 }
397 return 0;
398 }
399
__nft_match_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt,void * info)400 static void __nft_match_eval(const struct nft_expr *expr,
401 struct nft_regs *regs,
402 const struct nft_pktinfo *pkt,
403 void *info)
404 {
405 struct xt_match *match = expr->ops->data;
406 struct sk_buff *skb = pkt->skb;
407 struct xt_action_param xt;
408 bool ret;
409
410 nft_compat_set_par(&xt, pkt, match, info);
411
412 ret = match->match(skb, &xt);
413
414 if (xt.hotdrop) {
415 regs->verdict.code = NF_DROP;
416 return;
417 }
418
419 switch (ret ? 1 : 0) {
420 case 1:
421 regs->verdict.code = NFT_CONTINUE;
422 break;
423 case 0:
424 regs->verdict.code = NFT_BREAK;
425 break;
426 }
427 }
428
nft_match_large_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)429 static void nft_match_large_eval(const struct nft_expr *expr,
430 struct nft_regs *regs,
431 const struct nft_pktinfo *pkt)
432 {
433 struct nft_xt_match_priv *priv = nft_expr_priv(expr);
434
435 __nft_match_eval(expr, regs, pkt, priv->info);
436 }
437
nft_match_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)438 static void nft_match_eval(const struct nft_expr *expr,
439 struct nft_regs *regs,
440 const struct nft_pktinfo *pkt)
441 {
442 __nft_match_eval(expr, regs, pkt, nft_expr_priv(expr));
443 }
444
445 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
446 [NFTA_MATCH_NAME] = { .type = NLA_NUL_STRING,
447 .len = XT_EXTENSION_MAXNAMELEN },
448 [NFTA_MATCH_REV] = NLA_POLICY_MAX(NLA_BE32, 255),
449 [NFTA_MATCH_INFO] = { .type = NLA_BINARY },
450 };
451
452 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
453 static void
nft_match_set_mtchk_param(struct xt_mtchk_param * par,const struct nft_ctx * ctx,struct xt_match * match,void * info,union nft_entry * entry,u16 proto,bool inv)454 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
455 struct xt_match *match, void *info,
456 union nft_entry *entry, u16 proto, bool inv)
457 {
458 par->net = ctx->net;
459 par->table = ctx->table->name;
460 switch (ctx->family) {
461 case AF_INET:
462 entry->e4.ip.proto = proto;
463 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
464 break;
465 case AF_INET6:
466 if (proto)
467 entry->e6.ipv6.flags |= IP6T_F_PROTO;
468
469 entry->e6.ipv6.proto = proto;
470 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
471 break;
472 case NFPROTO_BRIDGE:
473 entry->ebt.ethproto = (__force __be16)proto;
474 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
475 break;
476 case NFPROTO_ARP:
477 break;
478 }
479 par->entryinfo = entry;
480 par->match = match;
481 par->matchinfo = info;
482 if (nft_is_base_chain(ctx->chain)) {
483 const struct nft_base_chain *basechain =
484 nft_base_chain(ctx->chain);
485 const struct nf_hook_ops *ops = &basechain->ops;
486
487 par->hook_mask = 1 << ops->hooknum;
488 } else {
489 par->hook_mask = 0;
490 }
491 par->family = ctx->family;
492 par->nft_compat = true;
493 }
494
match_compat_from_user(struct xt_match * m,void * in,void * out)495 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
496 {
497 int pad;
498
499 memcpy(out, in, m->matchsize);
500 pad = XT_ALIGN(m->matchsize) - m->matchsize;
501 if (pad > 0)
502 memset(out + m->matchsize, 0, pad);
503 }
504
505 static int
__nft_match_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[],void * info)506 __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
507 const struct nlattr * const tb[],
508 void *info)
509 {
510 struct xt_match *match = expr->ops->data;
511 struct xt_mtchk_param par;
512 size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
513 u16 proto = 0;
514 bool inv = false;
515 union nft_entry e = {};
516 int ret;
517
518 match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
519
520 if (ctx->nla[NFTA_RULE_COMPAT]) {
521 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
522 if (ret < 0)
523 return ret;
524 }
525
526 nft_compat_wait_for_destructors(ctx->net);
527
528 nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
529
530 return xt_check_match(&par, size, proto, inv);
531 }
532
533 static int
nft_match_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])534 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
535 const struct nlattr * const tb[])
536 {
537 return __nft_match_init(ctx, expr, tb, nft_expr_priv(expr));
538 }
539
540 static int
nft_match_large_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])541 nft_match_large_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
542 const struct nlattr * const tb[])
543 {
544 struct nft_xt_match_priv *priv = nft_expr_priv(expr);
545 struct xt_match *m = expr->ops->data;
546 int ret;
547
548 priv->info = kmalloc(XT_ALIGN(m->matchsize), GFP_KERNEL_ACCOUNT);
549 if (!priv->info)
550 return -ENOMEM;
551
552 ret = __nft_match_init(ctx, expr, tb, priv->info);
553 if (ret)
554 kfree(priv->info);
555 return ret;
556 }
557
558 static void
__nft_match_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr,void * info)559 __nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr,
560 void *info)
561 {
562 struct xt_match *match = expr->ops->data;
563 struct module *me = match->me;
564 struct xt_mtdtor_param par;
565
566 par.net = ctx->net;
567 par.match = match;
568 par.matchinfo = info;
569 par.family = ctx->family;
570 if (par.match->destroy != NULL)
571 par.match->destroy(&par);
572
573 __nft_mt_tg_destroy(me, expr);
574 }
575
576 static void
nft_match_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)577 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
578 {
579 __nft_match_destroy(ctx, expr, nft_expr_priv(expr));
580 }
581
582 static void
nft_match_large_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)583 nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
584 {
585 struct nft_xt_match_priv *priv = nft_expr_priv(expr);
586
587 __nft_match_destroy(ctx, expr, priv->info);
588 kfree(priv->info);
589 }
590
__nft_match_dump(struct sk_buff * skb,const struct nft_expr * expr,void * info)591 static int __nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr,
592 void *info)
593 {
594 struct xt_match *match = expr->ops->data;
595
596 if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
597 nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
598 nft_extension_dump_info(skb, NFTA_MATCH_INFO, info,
599 match->matchsize, match->usersize))
600 goto nla_put_failure;
601
602 return 0;
603
604 nla_put_failure:
605 return -1;
606 }
607
nft_match_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)608 static int nft_match_dump(struct sk_buff *skb,
609 const struct nft_expr *expr, bool reset)
610 {
611 return __nft_match_dump(skb, expr, nft_expr_priv(expr));
612 }
613
nft_match_large_dump(struct sk_buff * skb,const struct nft_expr * e,bool reset)614 static int nft_match_large_dump(struct sk_buff *skb,
615 const struct nft_expr *e, bool reset)
616 {
617 struct nft_xt_match_priv *priv = nft_expr_priv(e);
618
619 return __nft_match_dump(skb, e, priv->info);
620 }
621
nft_match_validate(const struct nft_ctx * ctx,const struct nft_expr * expr)622 static int nft_match_validate(const struct nft_ctx *ctx,
623 const struct nft_expr *expr)
624 {
625 int ret;
626
627 if (ctx->family != NFPROTO_IPV4 &&
628 ctx->family != NFPROTO_IPV6 &&
629 ctx->family != NFPROTO_INET &&
630 ctx->family != NFPROTO_BRIDGE &&
631 ctx->family != NFPROTO_ARP)
632 return -EOPNOTSUPP;
633
634 ret = nft_chain_validate_hooks(ctx->chain,
635 (1 << NF_INET_PRE_ROUTING) |
636 (1 << NF_INET_LOCAL_IN) |
637 (1 << NF_INET_FORWARD) |
638 (1 << NF_INET_LOCAL_OUT) |
639 (1 << NF_INET_POST_ROUTING));
640 if (ret)
641 return ret;
642
643 if (nft_is_base_chain(ctx->chain)) {
644 const struct nft_base_chain *basechain =
645 nft_base_chain(ctx->chain);
646 const struct nf_hook_ops *ops = &basechain->ops;
647 unsigned int hook_mask = 1 << ops->hooknum;
648 struct xt_match *match = expr->ops->data;
649 size_t size = XT_ALIGN(match->matchsize);
650 struct xt_mtchk_param par;
651 union nft_entry e = {};
652 void *info;
653
654 if (match->hooks && !(hook_mask & match->hooks))
655 return -EINVAL;
656
657 if (NFT_EXPR_SIZE(size) > NFT_MATCH_LARGE_THRESH) {
658 struct nft_xt_match_priv *priv = nft_expr_priv(expr);
659
660 info = priv->info;
661 } else {
662 info = nft_expr_priv(expr);
663 }
664
665 nft_match_set_mtchk_param(&par, ctx, match, info, &e, 0, false);
666
667 ret = xt_check_hooks_match(&par);
668 if (ret < 0)
669 return ret;
670
671 ret = nft_compat_chain_validate_dependency(ctx, match->table);
672 if (ret < 0)
673 return ret;
674 }
675 return 0;
676 }
677
678 static int
nfnl_compat_fill_info(struct sk_buff * skb,u32 portid,u32 seq,u32 type,int event,u16 family,const char * name,int rev,int target)679 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
680 int event, u16 family, const char *name,
681 int rev, int target)
682 {
683 struct nlmsghdr *nlh;
684 unsigned int flags = portid ? NLM_F_MULTI : 0;
685
686 event = nfnl_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
687 nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
688 NFNETLINK_V0, 0);
689 if (!nlh)
690 goto nlmsg_failure;
691
692 if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
693 nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
694 nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
695 goto nla_put_failure;
696
697 nlmsg_end(skb, nlh);
698 return skb->len;
699
700 nlmsg_failure:
701 nla_put_failure:
702 nlmsg_cancel(skb, nlh);
703 return -1;
704 }
705
nfnl_compat_get_rcu(struct sk_buff * skb,const struct nfnl_info * info,const struct nlattr * const tb[])706 static int nfnl_compat_get_rcu(struct sk_buff *skb,
707 const struct nfnl_info *info,
708 const struct nlattr * const tb[])
709 {
710 u8 family = info->nfmsg->nfgen_family;
711 const char *name, *fmt;
712 struct sk_buff *skb2;
713 int ret = 0, target;
714 u32 rev;
715
716 if (tb[NFTA_COMPAT_NAME] == NULL ||
717 tb[NFTA_COMPAT_REV] == NULL ||
718 tb[NFTA_COMPAT_TYPE] == NULL)
719 return -EINVAL;
720
721 name = nla_data(tb[NFTA_COMPAT_NAME]);
722 rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
723 /* x_tables api checks for 'target == 1' to mean target,
724 * everything else means 'match'.
725 * In x_tables world, the number is set by kernel, not
726 * userspace.
727 */
728 target = nla_get_be32(tb[NFTA_COMPAT_TYPE]) == htonl(1);
729
730 switch(family) {
731 case AF_INET:
732 fmt = "ipt_%s";
733 break;
734 case AF_INET6:
735 fmt = "ip6t_%s";
736 break;
737 case NFPROTO_BRIDGE:
738 fmt = "ebt_%s";
739 break;
740 case NFPROTO_ARP:
741 fmt = "arpt_%s";
742 break;
743 default:
744 pr_err("nft_compat: unsupported protocol %d\n", family);
745 return -EINVAL;
746 }
747
748 if (!try_module_get(THIS_MODULE))
749 return -EINVAL;
750
751 rcu_read_unlock();
752 try_then_request_module(xt_find_revision(family, name, rev, target, &ret),
753 fmt, name);
754 if (ret < 0)
755 goto out_put;
756
757 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
758 if (skb2 == NULL) {
759 ret = -ENOMEM;
760 goto out_put;
761 }
762
763 /* include the best revision for this extension in the message */
764 if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
765 info->nlh->nlmsg_seq,
766 NFNL_MSG_TYPE(info->nlh->nlmsg_type),
767 NFNL_MSG_COMPAT_GET,
768 family, name, ret, target) <= 0) {
769 kfree_skb(skb2);
770 goto out_put;
771 }
772
773 ret = nfnetlink_unicast(skb2, info->net, NETLINK_CB(skb).portid);
774 out_put:
775 rcu_read_lock();
776 module_put(THIS_MODULE);
777
778 return ret;
779 }
780
781 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
782 [NFTA_COMPAT_NAME] = { .type = NLA_NUL_STRING,
783 .len = NFT_COMPAT_NAME_MAX-1 },
784 [NFTA_COMPAT_REV] = NLA_POLICY_MAX(NLA_BE32, 255),
785 [NFTA_COMPAT_TYPE] = { .type = NLA_U32 },
786 };
787
788 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
789 [NFNL_MSG_COMPAT_GET] = {
790 .call = nfnl_compat_get_rcu,
791 .type = NFNL_CB_RCU,
792 .attr_count = NFTA_COMPAT_MAX,
793 .policy = nfnl_compat_policy_get
794 },
795 };
796
797 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
798 .name = "nft-compat",
799 .subsys_id = NFNL_SUBSYS_NFT_COMPAT,
800 .cb_count = NFNL_MSG_COMPAT_MAX,
801 .cb = nfnl_nft_compat_cb,
802 };
803
804 static struct nft_expr_type nft_match_type;
805
806 static const struct nft_expr_ops *
nft_match_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])807 nft_match_select_ops(const struct nft_ctx *ctx,
808 const struct nlattr * const tb[])
809 {
810 struct nft_expr_ops *ops;
811 struct xt_match *match;
812 unsigned int matchsize;
813 char *mt_name;
814 u32 rev, family;
815 int err;
816
817 if (tb[NFTA_MATCH_NAME] == NULL ||
818 tb[NFTA_MATCH_REV] == NULL ||
819 tb[NFTA_MATCH_INFO] == NULL)
820 return ERR_PTR(-EINVAL);
821
822 mt_name = nla_data(tb[NFTA_MATCH_NAME]);
823 rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
824 family = ctx->family;
825
826 match = xt_request_find_match(family, mt_name, rev);
827 if (IS_ERR(match))
828 return ERR_PTR(-ENOENT);
829
830 if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
831 err = -EINVAL;
832 goto err;
833 }
834
835 ops = kzalloc_obj(struct nft_expr_ops, GFP_KERNEL_ACCOUNT);
836 if (!ops) {
837 err = -ENOMEM;
838 goto err;
839 }
840
841 ops->type = &nft_match_type;
842 ops->eval = nft_match_eval;
843 ops->init = nft_match_init;
844 ops->destroy = nft_match_destroy;
845 ops->dump = nft_match_dump;
846 ops->validate = nft_match_validate;
847 ops->data = match;
848
849 matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
850 if (matchsize > NFT_MATCH_LARGE_THRESH) {
851 matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
852
853 ops->eval = nft_match_large_eval;
854 ops->init = nft_match_large_init;
855 ops->destroy = nft_match_large_destroy;
856 ops->dump = nft_match_large_dump;
857 }
858
859 ops->size = matchsize;
860
861 return ops;
862 err:
863 module_put(match->me);
864 return ERR_PTR(err);
865 }
866
nft_match_release_ops(const struct nft_expr_ops * ops)867 static void nft_match_release_ops(const struct nft_expr_ops *ops)
868 {
869 struct xt_match *match = ops->data;
870
871 module_put(match->me);
872 kfree(ops);
873 }
874
875 static struct nft_expr_type nft_match_type __read_mostly = {
876 .name = "match",
877 .select_ops = nft_match_select_ops,
878 .release_ops = nft_match_release_ops,
879 .policy = nft_match_policy,
880 .maxattr = NFTA_MATCH_MAX,
881 .owner = THIS_MODULE,
882 };
883
884 static struct nft_expr_type nft_target_type;
885
886 static const struct nft_expr_ops *
nft_target_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])887 nft_target_select_ops(const struct nft_ctx *ctx,
888 const struct nlattr * const tb[])
889 {
890 struct nft_expr_ops *ops;
891 struct xt_target *target;
892 char *tg_name;
893 u32 rev, family;
894 int err;
895
896 if (tb[NFTA_TARGET_NAME] == NULL ||
897 tb[NFTA_TARGET_REV] == NULL ||
898 tb[NFTA_TARGET_INFO] == NULL)
899 return ERR_PTR(-EINVAL);
900
901 tg_name = nla_data(tb[NFTA_TARGET_NAME]);
902 rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
903 family = ctx->family;
904
905 if (strcmp(tg_name, XT_ERROR_TARGET) == 0 ||
906 strcmp(tg_name, XT_STANDARD_TARGET) == 0 ||
907 strcmp(tg_name, "standard") == 0)
908 return ERR_PTR(-EINVAL);
909
910 target = xt_request_find_target(family, tg_name, rev);
911 if (IS_ERR(target))
912 return ERR_PTR(-ENOENT);
913
914 if (!target->target) {
915 err = -EINVAL;
916 goto err;
917 }
918
919 if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
920 err = -EINVAL;
921 goto err;
922 }
923
924 ops = kzalloc_obj(struct nft_expr_ops, GFP_KERNEL_ACCOUNT);
925 if (!ops) {
926 err = -ENOMEM;
927 goto err;
928 }
929
930 ops->type = &nft_target_type;
931 ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
932 ops->init = nft_target_init;
933 ops->destroy = nft_target_destroy;
934 ops->dump = nft_target_dump;
935 ops->validate = nft_target_validate;
936 ops->data = target;
937
938 if (family == NFPROTO_BRIDGE)
939 ops->eval = nft_target_eval_bridge;
940 else
941 ops->eval = nft_target_eval_xt;
942
943 return ops;
944 err:
945 module_put(target->me);
946 return ERR_PTR(err);
947 }
948
nft_target_release_ops(const struct nft_expr_ops * ops)949 static void nft_target_release_ops(const struct nft_expr_ops *ops)
950 {
951 struct xt_target *target = ops->data;
952
953 module_put(target->me);
954 kfree(ops);
955 }
956
957 static struct nft_expr_type nft_target_type __read_mostly = {
958 .name = "target",
959 .select_ops = nft_target_select_ops,
960 .release_ops = nft_target_release_ops,
961 .policy = nft_target_policy,
962 .maxattr = NFTA_TARGET_MAX,
963 .owner = THIS_MODULE,
964 };
965
nft_compat_module_init(void)966 static int __init nft_compat_module_init(void)
967 {
968 int ret;
969
970 ret = nft_register_expr(&nft_match_type);
971 if (ret < 0)
972 return ret;
973
974 ret = nft_register_expr(&nft_target_type);
975 if (ret < 0)
976 goto err_match;
977
978 ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
979 if (ret < 0) {
980 pr_err("nft_compat: cannot register with nfnetlink.\n");
981 goto err_target;
982 }
983
984 return ret;
985 err_target:
986 nft_unregister_expr(&nft_target_type);
987 err_match:
988 nft_unregister_expr(&nft_match_type);
989 return ret;
990 }
991
nft_compat_module_exit(void)992 static void __exit nft_compat_module_exit(void)
993 {
994 nfnetlink_subsys_unregister(&nfnl_compat_subsys);
995 nft_unregister_expr(&nft_target_type);
996 nft_unregister_expr(&nft_match_type);
997 }
998
999 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
1000
1001 module_init(nft_compat_module_init);
1002 module_exit(nft_compat_module_exit);
1003
1004 MODULE_LICENSE("GPL");
1005 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
1006 MODULE_ALIAS_NFT_EXPR("match");
1007 MODULE_ALIAS_NFT_EXPR("target");
1008 MODULE_DESCRIPTION("x_tables over nftables support");
1009