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