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netfilter: conntrack: remove prealloc support
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1 /*
2 * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/netlink.h>
15 #include <linux/netfilter.h>
16 #include <linux/netfilter/nfnetlink.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <linux/netfilter/nf_tables_compat.h>
19 #include <linux/netfilter/x_tables.h>
20 #include <linux/netfilter_ipv4/ip_tables.h>
21 #include <linux/netfilter_ipv6/ip6_tables.h>
22 #include <linux/netfilter_bridge/ebtables.h>
23 #include <linux/netfilter_arp/arp_tables.h>
24 #include <net/netfilter/nf_tables.h>
25
26 struct nft_xt {
27 struct list_head head;
28 struct nft_expr_ops ops;
29 unsigned int refcnt;
30 };
31
32 static void nft_xt_put(struct nft_xt *xt)
33 {
34 if (--xt->refcnt == 0) {
35 list_del(&xt->head);
36 kfree(xt);
37 }
38 }
39
40 static int nft_compat_chain_validate_dependency(const char *tablename,
41 const struct nft_chain *chain)
42 {
43 const struct nft_base_chain *basechain;
44
45 if (!tablename ||
46 !nft_is_base_chain(chain))
47 return 0;
48
49 basechain = nft_base_chain(chain);
50 if (strcmp(tablename, "nat") == 0 &&
51 basechain->type->type != NFT_CHAIN_T_NAT)
52 return -EINVAL;
53
54 return 0;
55 }
56
57 union nft_entry {
58 struct ipt_entry e4;
59 struct ip6t_entry e6;
60 struct ebt_entry ebt;
61 struct arpt_entry arp;
62 };
63
64 static inline void
65 nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
66 {
67 par->target = xt;
68 par->targinfo = xt_info;
69 par->hotdrop = false;
70 }
71
72 static void nft_target_eval_xt(const struct nft_expr *expr,
73 struct nft_regs *regs,
74 const struct nft_pktinfo *pkt)
75 {
76 void *info = nft_expr_priv(expr);
77 struct xt_target *target = expr->ops->data;
78 struct sk_buff *skb = pkt->skb;
79 int ret;
80
81 nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
82
83 ret = target->target(skb, &pkt->xt);
84
85 if (pkt->xt.hotdrop)
86 ret = NF_DROP;
87
88 switch (ret) {
89 case XT_CONTINUE:
90 regs->verdict.code = NFT_CONTINUE;
91 break;
92 default:
93 regs->verdict.code = ret;
94 break;
95 }
96 }
97
98 static void nft_target_eval_bridge(const struct nft_expr *expr,
99 struct nft_regs *regs,
100 const struct nft_pktinfo *pkt)
101 {
102 void *info = nft_expr_priv(expr);
103 struct xt_target *target = expr->ops->data;
104 struct sk_buff *skb = pkt->skb;
105 int ret;
106
107 nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
108
109 ret = target->target(skb, &pkt->xt);
110
111 if (pkt->xt.hotdrop)
112 ret = NF_DROP;
113
114 switch (ret) {
115 case EBT_ACCEPT:
116 regs->verdict.code = NF_ACCEPT;
117 break;
118 case EBT_DROP:
119 regs->verdict.code = NF_DROP;
120 break;
121 case EBT_CONTINUE:
122 regs->verdict.code = NFT_CONTINUE;
123 break;
124 case EBT_RETURN:
125 regs->verdict.code = NFT_RETURN;
126 break;
127 default:
128 regs->verdict.code = ret;
129 break;
130 }
131 }
132
133 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
134 [NFTA_TARGET_NAME] = { .type = NLA_NUL_STRING },
135 [NFTA_TARGET_REV] = { .type = NLA_U32 },
136 [NFTA_TARGET_INFO] = { .type = NLA_BINARY },
137 };
138
139 static void
140 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
141 const struct nft_ctx *ctx,
142 struct xt_target *target, void *info,
143 union nft_entry *entry, u16 proto, bool inv)
144 {
145 par->net = ctx->net;
146 par->table = ctx->table->name;
147 switch (ctx->afi->family) {
148 case AF_INET:
149 entry->e4.ip.proto = proto;
150 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
151 break;
152 case AF_INET6:
153 if (proto)
154 entry->e6.ipv6.flags |= IP6T_F_PROTO;
155
156 entry->e6.ipv6.proto = proto;
157 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
158 break;
159 case NFPROTO_BRIDGE:
160 entry->ebt.ethproto = (__force __be16)proto;
161 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
162 break;
163 case NFPROTO_ARP:
164 break;
165 }
166 par->entryinfo = entry;
167 par->target = target;
168 par->targinfo = info;
169 if (nft_is_base_chain(ctx->chain)) {
170 const struct nft_base_chain *basechain =
171 nft_base_chain(ctx->chain);
172 const struct nf_hook_ops *ops = &basechain->ops[0];
173
174 par->hook_mask = 1 << ops->hooknum;
175 } else {
176 par->hook_mask = 0;
177 }
178 par->family = ctx->afi->family;
179 par->nft_compat = true;
180 }
181
182 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
183 {
184 int pad;
185
186 memcpy(out, in, t->targetsize);
187 pad = XT_ALIGN(t->targetsize) - t->targetsize;
188 if (pad > 0)
189 memset(out + t->targetsize, 0, pad);
190 }
191
192 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
193 [NFTA_RULE_COMPAT_PROTO] = { .type = NLA_U32 },
194 [NFTA_RULE_COMPAT_FLAGS] = { .type = NLA_U32 },
195 };
196
197 static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
198 {
199 struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
200 u32 flags;
201 int err;
202
203 err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
204 nft_rule_compat_policy);
205 if (err < 0)
206 return err;
207
208 if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
209 return -EINVAL;
210
211 flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
212 if (flags & ~NFT_RULE_COMPAT_F_MASK)
213 return -EINVAL;
214 if (flags & NFT_RULE_COMPAT_F_INV)
215 *inv = true;
216
217 *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
218 return 0;
219 }
220
221 static int
222 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
223 const struct nlattr * const tb[])
224 {
225 void *info = nft_expr_priv(expr);
226 struct xt_target *target = expr->ops->data;
227 struct xt_tgchk_param par;
228 size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
229 u16 proto = 0;
230 bool inv = false;
231 union nft_entry e = {};
232 int ret;
233
234 target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
235
236 if (ctx->nla[NFTA_RULE_COMPAT]) {
237 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
238 if (ret < 0)
239 goto err;
240 }
241
242 nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
243
244 ret = xt_check_target(&par, size, proto, inv);
245 if (ret < 0)
246 goto err;
247
248 /* The standard target cannot be used */
249 if (target->target == NULL) {
250 ret = -EINVAL;
251 goto err;
252 }
253
254 return 0;
255 err:
256 module_put(target->me);
257 return ret;
258 }
259
260 static void
261 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
262 {
263 struct xt_target *target = expr->ops->data;
264 void *info = nft_expr_priv(expr);
265 struct xt_tgdtor_param par;
266
267 par.net = ctx->net;
268 par.target = target;
269 par.targinfo = info;
270 par.family = ctx->afi->family;
271 if (par.target->destroy != NULL)
272 par.target->destroy(&par);
273
274 nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
275 module_put(target->me);
276 }
277
278 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
279 {
280 const struct xt_target *target = expr->ops->data;
281 void *info = nft_expr_priv(expr);
282
283 if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
284 nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
285 nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
286 goto nla_put_failure;
287
288 return 0;
289
290 nla_put_failure:
291 return -1;
292 }
293
294 static int nft_target_validate(const struct nft_ctx *ctx,
295 const struct nft_expr *expr,
296 const struct nft_data **data)
297 {
298 struct xt_target *target = expr->ops->data;
299 unsigned int hook_mask = 0;
300 int ret;
301
302 if (nft_is_base_chain(ctx->chain)) {
303 const struct nft_base_chain *basechain =
304 nft_base_chain(ctx->chain);
305 const struct nf_hook_ops *ops = &basechain->ops[0];
306
307 hook_mask = 1 << ops->hooknum;
308 if (!(hook_mask & target->hooks))
309 return -EINVAL;
310
311 ret = nft_compat_chain_validate_dependency(target->table,
312 ctx->chain);
313 if (ret < 0)
314 return ret;
315 }
316 return 0;
317 }
318
319 static void nft_match_eval(const struct nft_expr *expr,
320 struct nft_regs *regs,
321 const struct nft_pktinfo *pkt)
322 {
323 void *info = nft_expr_priv(expr);
324 struct xt_match *match = expr->ops->data;
325 struct sk_buff *skb = pkt->skb;
326 bool ret;
327
328 nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
329
330 ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
331
332 if (pkt->xt.hotdrop) {
333 regs->verdict.code = NF_DROP;
334 return;
335 }
336
337 switch (ret ? 1 : 0) {
338 case 1:
339 regs->verdict.code = NFT_CONTINUE;
340 break;
341 case 0:
342 regs->verdict.code = NFT_BREAK;
343 break;
344 }
345 }
346
347 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
348 [NFTA_MATCH_NAME] = { .type = NLA_NUL_STRING },
349 [NFTA_MATCH_REV] = { .type = NLA_U32 },
350 [NFTA_MATCH_INFO] = { .type = NLA_BINARY },
351 };
352
353 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
354 static void
355 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
356 struct xt_match *match, void *info,
357 union nft_entry *entry, u16 proto, bool inv)
358 {
359 par->net = ctx->net;
360 par->table = ctx->table->name;
361 switch (ctx->afi->family) {
362 case AF_INET:
363 entry->e4.ip.proto = proto;
364 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
365 break;
366 case AF_INET6:
367 if (proto)
368 entry->e6.ipv6.flags |= IP6T_F_PROTO;
369
370 entry->e6.ipv6.proto = proto;
371 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
372 break;
373 case NFPROTO_BRIDGE:
374 entry->ebt.ethproto = (__force __be16)proto;
375 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
376 break;
377 case NFPROTO_ARP:
378 break;
379 }
380 par->entryinfo = entry;
381 par->match = match;
382 par->matchinfo = info;
383 if (nft_is_base_chain(ctx->chain)) {
384 const struct nft_base_chain *basechain =
385 nft_base_chain(ctx->chain);
386 const struct nf_hook_ops *ops = &basechain->ops[0];
387
388 par->hook_mask = 1 << ops->hooknum;
389 } else {
390 par->hook_mask = 0;
391 }
392 par->family = ctx->afi->family;
393 par->nft_compat = true;
394 }
395
396 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
397 {
398 int pad;
399
400 memcpy(out, in, m->matchsize);
401 pad = XT_ALIGN(m->matchsize) - m->matchsize;
402 if (pad > 0)
403 memset(out + m->matchsize, 0, pad);
404 }
405
406 static int
407 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
408 const struct nlattr * const tb[])
409 {
410 void *info = nft_expr_priv(expr);
411 struct xt_match *match = expr->ops->data;
412 struct xt_mtchk_param par;
413 size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
414 u16 proto = 0;
415 bool inv = false;
416 union nft_entry e = {};
417 int ret;
418
419 match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
420
421 if (ctx->nla[NFTA_RULE_COMPAT]) {
422 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
423 if (ret < 0)
424 goto err;
425 }
426
427 nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
428
429 ret = xt_check_match(&par, size, proto, inv);
430 if (ret < 0)
431 goto err;
432
433 return 0;
434 err:
435 module_put(match->me);
436 return ret;
437 }
438
439 static void
440 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
441 {
442 struct xt_match *match = expr->ops->data;
443 void *info = nft_expr_priv(expr);
444 struct xt_mtdtor_param par;
445
446 par.net = ctx->net;
447 par.match = match;
448 par.matchinfo = info;
449 par.family = ctx->afi->family;
450 if (par.match->destroy != NULL)
451 par.match->destroy(&par);
452
453 nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
454 module_put(match->me);
455 }
456
457 static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
458 {
459 void *info = nft_expr_priv(expr);
460 struct xt_match *match = expr->ops->data;
461
462 if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
463 nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
464 nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
465 goto nla_put_failure;
466
467 return 0;
468
469 nla_put_failure:
470 return -1;
471 }
472
473 static int nft_match_validate(const struct nft_ctx *ctx,
474 const struct nft_expr *expr,
475 const struct nft_data **data)
476 {
477 struct xt_match *match = expr->ops->data;
478 unsigned int hook_mask = 0;
479 int ret;
480
481 if (nft_is_base_chain(ctx->chain)) {
482 const struct nft_base_chain *basechain =
483 nft_base_chain(ctx->chain);
484 const struct nf_hook_ops *ops = &basechain->ops[0];
485
486 hook_mask = 1 << ops->hooknum;
487 if (!(hook_mask & match->hooks))
488 return -EINVAL;
489
490 ret = nft_compat_chain_validate_dependency(match->table,
491 ctx->chain);
492 if (ret < 0)
493 return ret;
494 }
495 return 0;
496 }
497
498 static int
499 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
500 int event, u16 family, const char *name,
501 int rev, int target)
502 {
503 struct nlmsghdr *nlh;
504 struct nfgenmsg *nfmsg;
505 unsigned int flags = portid ? NLM_F_MULTI : 0;
506
507 event = nfnl_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
508 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
509 if (nlh == NULL)
510 goto nlmsg_failure;
511
512 nfmsg = nlmsg_data(nlh);
513 nfmsg->nfgen_family = family;
514 nfmsg->version = NFNETLINK_V0;
515 nfmsg->res_id = 0;
516
517 if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
518 nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
519 nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
520 goto nla_put_failure;
521
522 nlmsg_end(skb, nlh);
523 return skb->len;
524
525 nlmsg_failure:
526 nla_put_failure:
527 nlmsg_cancel(skb, nlh);
528 return -1;
529 }
530
531 static int nfnl_compat_get(struct net *net, struct sock *nfnl,
532 struct sk_buff *skb, const struct nlmsghdr *nlh,
533 const struct nlattr * const tb[])
534 {
535 int ret = 0, target;
536 struct nfgenmsg *nfmsg;
537 const char *fmt;
538 const char *name;
539 u32 rev;
540 struct sk_buff *skb2;
541
542 if (tb[NFTA_COMPAT_NAME] == NULL ||
543 tb[NFTA_COMPAT_REV] == NULL ||
544 tb[NFTA_COMPAT_TYPE] == NULL)
545 return -EINVAL;
546
547 name = nla_data(tb[NFTA_COMPAT_NAME]);
548 rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
549 target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
550
551 nfmsg = nlmsg_data(nlh);
552
553 switch(nfmsg->nfgen_family) {
554 case AF_INET:
555 fmt = "ipt_%s";
556 break;
557 case AF_INET6:
558 fmt = "ip6t_%s";
559 break;
560 case NFPROTO_BRIDGE:
561 fmt = "ebt_%s";
562 break;
563 case NFPROTO_ARP:
564 fmt = "arpt_%s";
565 break;
566 default:
567 pr_err("nft_compat: unsupported protocol %d\n",
568 nfmsg->nfgen_family);
569 return -EINVAL;
570 }
571
572 try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
573 rev, target, &ret),
574 fmt, name);
575
576 if (ret < 0)
577 return ret;
578
579 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
580 if (skb2 == NULL)
581 return -ENOMEM;
582
583 /* include the best revision for this extension in the message */
584 if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
585 nlh->nlmsg_seq,
586 NFNL_MSG_TYPE(nlh->nlmsg_type),
587 NFNL_MSG_COMPAT_GET,
588 nfmsg->nfgen_family,
589 name, ret, target) <= 0) {
590 kfree_skb(skb2);
591 return -ENOSPC;
592 }
593
594 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
595 MSG_DONTWAIT);
596 if (ret > 0)
597 ret = 0;
598
599 return ret == -EAGAIN ? -ENOBUFS : ret;
600 }
601
602 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
603 [NFTA_COMPAT_NAME] = { .type = NLA_NUL_STRING,
604 .len = NFT_COMPAT_NAME_MAX-1 },
605 [NFTA_COMPAT_REV] = { .type = NLA_U32 },
606 [NFTA_COMPAT_TYPE] = { .type = NLA_U32 },
607 };
608
609 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
610 [NFNL_MSG_COMPAT_GET] = { .call = nfnl_compat_get,
611 .attr_count = NFTA_COMPAT_MAX,
612 .policy = nfnl_compat_policy_get },
613 };
614
615 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
616 .name = "nft-compat",
617 .subsys_id = NFNL_SUBSYS_NFT_COMPAT,
618 .cb_count = NFNL_MSG_COMPAT_MAX,
619 .cb = nfnl_nft_compat_cb,
620 };
621
622 static LIST_HEAD(nft_match_list);
623
624 static struct nft_expr_type nft_match_type;
625
626 static bool nft_match_cmp(const struct xt_match *match,
627 const char *name, u32 rev, u32 family)
628 {
629 return strcmp(match->name, name) == 0 && match->revision == rev &&
630 (match->family == NFPROTO_UNSPEC || match->family == family);
631 }
632
633 static const struct nft_expr_ops *
634 nft_match_select_ops(const struct nft_ctx *ctx,
635 const struct nlattr * const tb[])
636 {
637 struct nft_xt *nft_match;
638 struct xt_match *match;
639 char *mt_name;
640 u32 rev, family;
641 int err;
642
643 if (tb[NFTA_MATCH_NAME] == NULL ||
644 tb[NFTA_MATCH_REV] == NULL ||
645 tb[NFTA_MATCH_INFO] == NULL)
646 return ERR_PTR(-EINVAL);
647
648 mt_name = nla_data(tb[NFTA_MATCH_NAME]);
649 rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
650 family = ctx->afi->family;
651
652 /* Re-use the existing match if it's already loaded. */
653 list_for_each_entry(nft_match, &nft_match_list, head) {
654 struct xt_match *match = nft_match->ops.data;
655
656 if (nft_match_cmp(match, mt_name, rev, family)) {
657 if (!try_module_get(match->me))
658 return ERR_PTR(-ENOENT);
659
660 nft_match->refcnt++;
661 return &nft_match->ops;
662 }
663 }
664
665 match = xt_request_find_match(family, mt_name, rev);
666 if (IS_ERR(match))
667 return ERR_PTR(-ENOENT);
668
669 if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
670 err = -EINVAL;
671 goto err;
672 }
673
674 /* This is the first time we use this match, allocate operations */
675 nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
676 if (nft_match == NULL) {
677 err = -ENOMEM;
678 goto err;
679 }
680
681 nft_match->refcnt = 1;
682 nft_match->ops.type = &nft_match_type;
683 nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
684 nft_match->ops.eval = nft_match_eval;
685 nft_match->ops.init = nft_match_init;
686 nft_match->ops.destroy = nft_match_destroy;
687 nft_match->ops.dump = nft_match_dump;
688 nft_match->ops.validate = nft_match_validate;
689 nft_match->ops.data = match;
690
691 list_add(&nft_match->head, &nft_match_list);
692
693 return &nft_match->ops;
694 err:
695 module_put(match->me);
696 return ERR_PTR(err);
697 }
698
699 static struct nft_expr_type nft_match_type __read_mostly = {
700 .name = "match",
701 .select_ops = nft_match_select_ops,
702 .policy = nft_match_policy,
703 .maxattr = NFTA_MATCH_MAX,
704 .owner = THIS_MODULE,
705 };
706
707 static LIST_HEAD(nft_target_list);
708
709 static struct nft_expr_type nft_target_type;
710
711 static bool nft_target_cmp(const struct xt_target *tg,
712 const char *name, u32 rev, u32 family)
713 {
714 return strcmp(tg->name, name) == 0 && tg->revision == rev &&
715 (tg->family == NFPROTO_UNSPEC || tg->family == family);
716 }
717
718 static const struct nft_expr_ops *
719 nft_target_select_ops(const struct nft_ctx *ctx,
720 const struct nlattr * const tb[])
721 {
722 struct nft_xt *nft_target;
723 struct xt_target *target;
724 char *tg_name;
725 u32 rev, family;
726 int err;
727
728 if (tb[NFTA_TARGET_NAME] == NULL ||
729 tb[NFTA_TARGET_REV] == NULL ||
730 tb[NFTA_TARGET_INFO] == NULL)
731 return ERR_PTR(-EINVAL);
732
733 tg_name = nla_data(tb[NFTA_TARGET_NAME]);
734 rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
735 family = ctx->afi->family;
736
737 /* Re-use the existing target if it's already loaded. */
738 list_for_each_entry(nft_target, &nft_target_list, head) {
739 struct xt_target *target = nft_target->ops.data;
740
741 if (nft_target_cmp(target, tg_name, rev, family)) {
742 if (!try_module_get(target->me))
743 return ERR_PTR(-ENOENT);
744
745 nft_target->refcnt++;
746 return &nft_target->ops;
747 }
748 }
749
750 target = xt_request_find_target(family, tg_name, rev);
751 if (IS_ERR(target))
752 return ERR_PTR(-ENOENT);
753
754 if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
755 err = -EINVAL;
756 goto err;
757 }
758
759 /* This is the first time we use this target, allocate operations */
760 nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
761 if (nft_target == NULL) {
762 err = -ENOMEM;
763 goto err;
764 }
765
766 nft_target->refcnt = 1;
767 nft_target->ops.type = &nft_target_type;
768 nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
769 nft_target->ops.init = nft_target_init;
770 nft_target->ops.destroy = nft_target_destroy;
771 nft_target->ops.dump = nft_target_dump;
772 nft_target->ops.validate = nft_target_validate;
773 nft_target->ops.data = target;
774
775 if (family == NFPROTO_BRIDGE)
776 nft_target->ops.eval = nft_target_eval_bridge;
777 else
778 nft_target->ops.eval = nft_target_eval_xt;
779
780 list_add(&nft_target->head, &nft_target_list);
781
782 return &nft_target->ops;
783 err:
784 module_put(target->me);
785 return ERR_PTR(err);
786 }
787
788 static struct nft_expr_type nft_target_type __read_mostly = {
789 .name = "target",
790 .select_ops = nft_target_select_ops,
791 .policy = nft_target_policy,
792 .maxattr = NFTA_TARGET_MAX,
793 .owner = THIS_MODULE,
794 };
795
796 static int __init nft_compat_module_init(void)
797 {
798 int ret;
799
800 ret = nft_register_expr(&nft_match_type);
801 if (ret < 0)
802 return ret;
803
804 ret = nft_register_expr(&nft_target_type);
805 if (ret < 0)
806 goto err_match;
807
808 ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
809 if (ret < 0) {
810 pr_err("nft_compat: cannot register with nfnetlink.\n");
811 goto err_target;
812 }
813
814 pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
815
816 return ret;
817
818 err_target:
819 nft_unregister_expr(&nft_target_type);
820 err_match:
821 nft_unregister_expr(&nft_match_type);
822 return ret;
823 }
824
825 static void __exit nft_compat_module_exit(void)
826 {
827 nfnetlink_subsys_unregister(&nfnl_compat_subsys);
828 nft_unregister_expr(&nft_target_type);
829 nft_unregister_expr(&nft_match_type);
830 }
831
832 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
833
834 module_init(nft_compat_module_init);
835 module_exit(nft_compat_module_exit);
836
837 MODULE_LICENSE("GPL");
838 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
839 MODULE_ALIAS_NFT_EXPR("match");
840 MODULE_ALIAS_NFT_EXPR("target");
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