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 <net/netfilter/nf_tables.h>
23
nft_compat_chain_validate_dependency(const char * tablename,const struct nft_chain * chain)24 static int nft_compat_chain_validate_dependency(const char *tablename,
25 const struct nft_chain *chain)
26 {
27 const struct nft_base_chain *basechain;
28
29 if (!tablename || !(chain->flags & NFT_BASE_CHAIN))
30 return 0;
31
32 basechain = nft_base_chain(chain);
33 if (strcmp(tablename, "nat") == 0 &&
34 basechain->type->type != NFT_CHAIN_T_NAT)
35 return -EINVAL;
36
37 return 0;
38 }
39
40 union nft_entry {
41 struct ipt_entry e4;
42 struct ip6t_entry e6;
43 };
44
45 static inline void
nft_compat_set_par(struct xt_action_param * par,void * xt,const void * xt_info)46 nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
47 {
48 par->target = xt;
49 par->targinfo = xt_info;
50 par->hotdrop = false;
51 }
52
nft_target_eval(const struct nft_expr * expr,struct nft_data data[NFT_REG_MAX+1],const struct nft_pktinfo * pkt)53 static void nft_target_eval(const struct nft_expr *expr,
54 struct nft_data data[NFT_REG_MAX + 1],
55 const struct nft_pktinfo *pkt)
56 {
57 void *info = nft_expr_priv(expr);
58 struct xt_target *target = expr->ops->data;
59 struct sk_buff *skb = pkt->skb;
60 int ret;
61
62 nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
63
64 ret = target->target(skb, &pkt->xt);
65
66 if (pkt->xt.hotdrop)
67 ret = NF_DROP;
68
69 switch(ret) {
70 case XT_CONTINUE:
71 data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
72 break;
73 default:
74 data[NFT_REG_VERDICT].verdict = ret;
75 break;
76 }
77 return;
78 }
79
80 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
81 [NFTA_TARGET_NAME] = { .type = NLA_NUL_STRING },
82 [NFTA_TARGET_REV] = { .type = NLA_U32 },
83 [NFTA_TARGET_INFO] = { .type = NLA_BINARY },
84 };
85
86 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,u8 proto,bool inv)87 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
88 const struct nft_ctx *ctx,
89 struct xt_target *target, void *info,
90 union nft_entry *entry, u8 proto, bool inv)
91 {
92 par->net = ctx->net;
93 par->table = ctx->table->name;
94 switch (ctx->afi->family) {
95 case AF_INET:
96 entry->e4.ip.proto = proto;
97 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
98 break;
99 case AF_INET6:
100 if (proto)
101 entry->e6.ipv6.flags |= IP6T_F_PROTO;
102
103 entry->e6.ipv6.proto = proto;
104 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
105 break;
106 }
107 par->entryinfo = entry;
108 par->target = target;
109 par->targinfo = info;
110 if (ctx->chain->flags & NFT_BASE_CHAIN) {
111 const struct nft_base_chain *basechain =
112 nft_base_chain(ctx->chain);
113 const struct nf_hook_ops *ops = &basechain->ops[0];
114
115 par->hook_mask = 1 << ops->hooknum;
116 } else {
117 par->hook_mask = 0;
118 }
119 par->family = ctx->afi->family;
120 }
121
target_compat_from_user(struct xt_target * t,void * in,void * out)122 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
123 {
124 int pad;
125
126 memcpy(out, in, t->targetsize);
127 pad = XT_ALIGN(t->targetsize) - t->targetsize;
128 if (pad > 0)
129 memset(out + t->targetsize, 0, pad);
130 }
131
132 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
133 [NFTA_RULE_COMPAT_PROTO] = { .type = NLA_U32 },
134 [NFTA_RULE_COMPAT_FLAGS] = { .type = NLA_U32 },
135 };
136
nft_parse_compat(const struct nlattr * attr,u8 * proto,bool * inv)137 static int nft_parse_compat(const struct nlattr *attr, u8 *proto, bool *inv)
138 {
139 struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
140 u32 flags;
141 int err;
142
143 err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
144 nft_rule_compat_policy);
145 if (err < 0)
146 return err;
147
148 if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
149 return -EINVAL;
150
151 flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
152 if (flags & ~NFT_RULE_COMPAT_F_MASK)
153 return -EINVAL;
154 if (flags & NFT_RULE_COMPAT_F_INV)
155 *inv = true;
156
157 *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
158 return 0;
159 }
160
161 static int
nft_target_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])162 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
163 const struct nlattr * const tb[])
164 {
165 void *info = nft_expr_priv(expr);
166 struct xt_target *target = expr->ops->data;
167 struct xt_tgchk_param par;
168 size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
169 u8 proto = 0;
170 bool inv = false;
171 union nft_entry e = {};
172 int ret;
173
174 ret = nft_compat_chain_validate_dependency(target->table, ctx->chain);
175 if (ret < 0)
176 goto err;
177
178 target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
179
180 if (ctx->nla[NFTA_RULE_COMPAT]) {
181 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
182 if (ret < 0)
183 goto err;
184 }
185
186 nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
187
188 ret = xt_check_target(&par, size, proto, inv);
189 if (ret < 0)
190 goto err;
191
192 /* The standard target cannot be used */
193 if (target->target == NULL) {
194 ret = -EINVAL;
195 goto err;
196 }
197
198 return 0;
199 err:
200 module_put(target->me);
201 return ret;
202 }
203
204 static void
nft_target_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)205 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
206 {
207 struct xt_target *target = expr->ops->data;
208 void *info = nft_expr_priv(expr);
209 struct xt_tgdtor_param par;
210
211 par.net = ctx->net;
212 par.target = target;
213 par.targinfo = info;
214 par.family = ctx->afi->family;
215 if (par.target->destroy != NULL)
216 par.target->destroy(&par);
217
218 module_put(target->me);
219 }
220
nft_target_dump(struct sk_buff * skb,const struct nft_expr * expr)221 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
222 {
223 const struct xt_target *target = expr->ops->data;
224 void *info = nft_expr_priv(expr);
225
226 if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
227 nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
228 nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
229 goto nla_put_failure;
230
231 return 0;
232
233 nla_put_failure:
234 return -1;
235 }
236
nft_target_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** data)237 static int nft_target_validate(const struct nft_ctx *ctx,
238 const struct nft_expr *expr,
239 const struct nft_data **data)
240 {
241 struct xt_target *target = expr->ops->data;
242 unsigned int hook_mask = 0;
243 int ret;
244
245 if (ctx->chain->flags & NFT_BASE_CHAIN) {
246 const struct nft_base_chain *basechain =
247 nft_base_chain(ctx->chain);
248 const struct nf_hook_ops *ops = &basechain->ops[0];
249
250 hook_mask = 1 << ops->hooknum;
251 if (!(hook_mask & target->hooks))
252 return -EINVAL;
253
254 ret = nft_compat_chain_validate_dependency(target->table,
255 ctx->chain);
256 if (ret < 0)
257 return ret;
258 }
259 return 0;
260 }
261
nft_match_eval(const struct nft_expr * expr,struct nft_data data[NFT_REG_MAX+1],const struct nft_pktinfo * pkt)262 static void nft_match_eval(const struct nft_expr *expr,
263 struct nft_data data[NFT_REG_MAX + 1],
264 const struct nft_pktinfo *pkt)
265 {
266 void *info = nft_expr_priv(expr);
267 struct xt_match *match = expr->ops->data;
268 struct sk_buff *skb = pkt->skb;
269 bool ret;
270
271 nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
272
273 ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
274
275 if (pkt->xt.hotdrop) {
276 data[NFT_REG_VERDICT].verdict = NF_DROP;
277 return;
278 }
279
280 switch (ret ? 1 : 0) {
281 case 1:
282 data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
283 break;
284 case 0:
285 data[NFT_REG_VERDICT].verdict = NFT_BREAK;
286 break;
287 }
288 }
289
290 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
291 [NFTA_MATCH_NAME] = { .type = NLA_NUL_STRING },
292 [NFTA_MATCH_REV] = { .type = NLA_U32 },
293 [NFTA_MATCH_INFO] = { .type = NLA_BINARY },
294 };
295
296 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
297 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,u8 proto,bool inv)298 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
299 struct xt_match *match, void *info,
300 union nft_entry *entry, u8 proto, bool inv)
301 {
302 par->net = ctx->net;
303 par->table = ctx->table->name;
304 switch (ctx->afi->family) {
305 case AF_INET:
306 entry->e4.ip.proto = proto;
307 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
308 break;
309 case AF_INET6:
310 if (proto)
311 entry->e6.ipv6.flags |= IP6T_F_PROTO;
312
313 entry->e6.ipv6.proto = proto;
314 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
315 break;
316 }
317 par->entryinfo = entry;
318 par->match = match;
319 par->matchinfo = info;
320 if (ctx->chain->flags & NFT_BASE_CHAIN) {
321 const struct nft_base_chain *basechain =
322 nft_base_chain(ctx->chain);
323 const struct nf_hook_ops *ops = &basechain->ops[0];
324
325 par->hook_mask = 1 << ops->hooknum;
326 } else {
327 par->hook_mask = 0;
328 }
329 par->family = ctx->afi->family;
330 }
331
match_compat_from_user(struct xt_match * m,void * in,void * out)332 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
333 {
334 int pad;
335
336 memcpy(out, in, m->matchsize);
337 pad = XT_ALIGN(m->matchsize) - m->matchsize;
338 if (pad > 0)
339 memset(out + m->matchsize, 0, pad);
340 }
341
342 static int
nft_match_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])343 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
344 const struct nlattr * const tb[])
345 {
346 void *info = nft_expr_priv(expr);
347 struct xt_match *match = expr->ops->data;
348 struct xt_mtchk_param par;
349 size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
350 u8 proto = 0;
351 bool inv = false;
352 union nft_entry e = {};
353 int ret;
354
355 ret = nft_compat_chain_validate_dependency(match->table, ctx->chain);
356 if (ret < 0)
357 goto err;
358
359 match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
360
361 if (ctx->nla[NFTA_RULE_COMPAT]) {
362 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
363 if (ret < 0)
364 goto err;
365 }
366
367 nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
368
369 ret = xt_check_match(&par, size, proto, inv);
370 if (ret < 0)
371 goto err;
372
373 return 0;
374 err:
375 module_put(match->me);
376 return ret;
377 }
378
379 static void
nft_match_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)380 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
381 {
382 struct xt_match *match = expr->ops->data;
383 void *info = nft_expr_priv(expr);
384 struct xt_mtdtor_param par;
385
386 par.net = ctx->net;
387 par.match = match;
388 par.matchinfo = info;
389 par.family = ctx->afi->family;
390 if (par.match->destroy != NULL)
391 par.match->destroy(&par);
392
393 module_put(match->me);
394 }
395
nft_match_dump(struct sk_buff * skb,const struct nft_expr * expr)396 static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
397 {
398 void *info = nft_expr_priv(expr);
399 struct xt_match *match = expr->ops->data;
400
401 if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
402 nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
403 nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
404 goto nla_put_failure;
405
406 return 0;
407
408 nla_put_failure:
409 return -1;
410 }
411
nft_match_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** data)412 static int nft_match_validate(const struct nft_ctx *ctx,
413 const struct nft_expr *expr,
414 const struct nft_data **data)
415 {
416 struct xt_match *match = expr->ops->data;
417 unsigned int hook_mask = 0;
418 int ret;
419
420 if (ctx->chain->flags & NFT_BASE_CHAIN) {
421 const struct nft_base_chain *basechain =
422 nft_base_chain(ctx->chain);
423 const struct nf_hook_ops *ops = &basechain->ops[0];
424
425 hook_mask = 1 << ops->hooknum;
426 if (!(hook_mask & match->hooks))
427 return -EINVAL;
428
429 ret = nft_compat_chain_validate_dependency(match->table,
430 ctx->chain);
431 if (ret < 0)
432 return ret;
433 }
434 return 0;
435 }
436
437 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)438 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
439 int event, u16 family, const char *name,
440 int rev, int target)
441 {
442 struct nlmsghdr *nlh;
443 struct nfgenmsg *nfmsg;
444 unsigned int flags = portid ? NLM_F_MULTI : 0;
445
446 event |= NFNL_SUBSYS_NFT_COMPAT << 8;
447 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
448 if (nlh == NULL)
449 goto nlmsg_failure;
450
451 nfmsg = nlmsg_data(nlh);
452 nfmsg->nfgen_family = family;
453 nfmsg->version = NFNETLINK_V0;
454 nfmsg->res_id = 0;
455
456 if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
457 nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
458 nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
459 goto nla_put_failure;
460
461 nlmsg_end(skb, nlh);
462 return skb->len;
463
464 nlmsg_failure:
465 nla_put_failure:
466 nlmsg_cancel(skb, nlh);
467 return -1;
468 }
469
470 static int
nfnl_compat_get(struct sock * nfnl,struct sk_buff * skb,const struct nlmsghdr * nlh,const struct nlattr * const tb[])471 nfnl_compat_get(struct sock *nfnl, struct sk_buff *skb,
472 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
473 {
474 int ret = 0, target;
475 struct nfgenmsg *nfmsg;
476 const char *fmt;
477 const char *name;
478 u32 rev;
479 struct sk_buff *skb2;
480
481 if (tb[NFTA_COMPAT_NAME] == NULL ||
482 tb[NFTA_COMPAT_REV] == NULL ||
483 tb[NFTA_COMPAT_TYPE] == NULL)
484 return -EINVAL;
485
486 name = nla_data(tb[NFTA_COMPAT_NAME]);
487 rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
488 target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
489
490 nfmsg = nlmsg_data(nlh);
491
492 switch(nfmsg->nfgen_family) {
493 case AF_INET:
494 fmt = "ipt_%s";
495 break;
496 case AF_INET6:
497 fmt = "ip6t_%s";
498 break;
499 default:
500 pr_err("nft_compat: unsupported protocol %d\n",
501 nfmsg->nfgen_family);
502 return -EINVAL;
503 }
504
505 try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
506 rev, target, &ret),
507 fmt, name);
508
509 if (ret < 0)
510 return ret;
511
512 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
513 if (skb2 == NULL)
514 return -ENOMEM;
515
516 /* include the best revision for this extension in the message */
517 if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
518 nlh->nlmsg_seq,
519 NFNL_MSG_TYPE(nlh->nlmsg_type),
520 NFNL_MSG_COMPAT_GET,
521 nfmsg->nfgen_family,
522 name, ret, target) <= 0) {
523 kfree_skb(skb2);
524 return -ENOSPC;
525 }
526
527 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
528 MSG_DONTWAIT);
529 if (ret > 0)
530 ret = 0;
531
532 return ret == -EAGAIN ? -ENOBUFS : ret;
533 }
534
535 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
536 [NFTA_COMPAT_NAME] = { .type = NLA_NUL_STRING,
537 .len = NFT_COMPAT_NAME_MAX-1 },
538 [NFTA_COMPAT_REV] = { .type = NLA_U32 },
539 [NFTA_COMPAT_TYPE] = { .type = NLA_U32 },
540 };
541
542 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
543 [NFNL_MSG_COMPAT_GET] = { .call = nfnl_compat_get,
544 .attr_count = NFTA_COMPAT_MAX,
545 .policy = nfnl_compat_policy_get },
546 };
547
548 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
549 .name = "nft-compat",
550 .subsys_id = NFNL_SUBSYS_NFT_COMPAT,
551 .cb_count = NFNL_MSG_COMPAT_MAX,
552 .cb = nfnl_nft_compat_cb,
553 };
554
555 static LIST_HEAD(nft_match_list);
556
557 struct nft_xt {
558 struct list_head head;
559 struct nft_expr_ops ops;
560 };
561
562 static struct nft_expr_type nft_match_type;
563
nft_match_cmp(const struct xt_match * match,const char * name,u32 rev,u32 family)564 static bool nft_match_cmp(const struct xt_match *match,
565 const char *name, u32 rev, u32 family)
566 {
567 return strcmp(match->name, name) == 0 && match->revision == rev &&
568 (match->family == NFPROTO_UNSPEC || match->family == family);
569 }
570
571 static const struct nft_expr_ops *
nft_match_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])572 nft_match_select_ops(const struct nft_ctx *ctx,
573 const struct nlattr * const tb[])
574 {
575 struct nft_xt *nft_match;
576 struct xt_match *match;
577 char *mt_name;
578 u32 rev, family;
579
580 if (tb[NFTA_MATCH_NAME] == NULL ||
581 tb[NFTA_MATCH_REV] == NULL ||
582 tb[NFTA_MATCH_INFO] == NULL)
583 return ERR_PTR(-EINVAL);
584
585 mt_name = nla_data(tb[NFTA_MATCH_NAME]);
586 rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
587 family = ctx->afi->family;
588
589 /* Re-use the existing match if it's already loaded. */
590 list_for_each_entry(nft_match, &nft_match_list, head) {
591 struct xt_match *match = nft_match->ops.data;
592
593 if (nft_match_cmp(match, mt_name, rev, family)) {
594 if (!try_module_get(match->me))
595 return ERR_PTR(-ENOENT);
596
597 return &nft_match->ops;
598 }
599 }
600
601 match = xt_request_find_match(family, mt_name, rev);
602 if (IS_ERR(match))
603 return ERR_PTR(-ENOENT);
604
605 /* This is the first time we use this match, allocate operations */
606 nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
607 if (nft_match == NULL)
608 return ERR_PTR(-ENOMEM);
609
610 nft_match->ops.type = &nft_match_type;
611 nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
612 nft_match->ops.eval = nft_match_eval;
613 nft_match->ops.init = nft_match_init;
614 nft_match->ops.destroy = nft_match_destroy;
615 nft_match->ops.dump = nft_match_dump;
616 nft_match->ops.validate = nft_match_validate;
617 nft_match->ops.data = match;
618
619 list_add(&nft_match->head, &nft_match_list);
620
621 return &nft_match->ops;
622 }
623
nft_match_release(void)624 static void nft_match_release(void)
625 {
626 struct nft_xt *nft_match, *tmp;
627
628 list_for_each_entry_safe(nft_match, tmp, &nft_match_list, head)
629 kfree(nft_match);
630 }
631
632 static struct nft_expr_type nft_match_type __read_mostly = {
633 .name = "match",
634 .select_ops = nft_match_select_ops,
635 .policy = nft_match_policy,
636 .maxattr = NFTA_MATCH_MAX,
637 .owner = THIS_MODULE,
638 };
639
640 static LIST_HEAD(nft_target_list);
641
642 static struct nft_expr_type nft_target_type;
643
nft_target_cmp(const struct xt_target * tg,const char * name,u32 rev,u32 family)644 static bool nft_target_cmp(const struct xt_target *tg,
645 const char *name, u32 rev, u32 family)
646 {
647 return strcmp(tg->name, name) == 0 && tg->revision == rev &&
648 (tg->family == NFPROTO_UNSPEC || tg->family == family);
649 }
650
651 static const struct nft_expr_ops *
nft_target_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])652 nft_target_select_ops(const struct nft_ctx *ctx,
653 const struct nlattr * const tb[])
654 {
655 struct nft_xt *nft_target;
656 struct xt_target *target;
657 char *tg_name;
658 u32 rev, family;
659
660 if (tb[NFTA_TARGET_NAME] == NULL ||
661 tb[NFTA_TARGET_REV] == NULL ||
662 tb[NFTA_TARGET_INFO] == NULL)
663 return ERR_PTR(-EINVAL);
664
665 tg_name = nla_data(tb[NFTA_TARGET_NAME]);
666 rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
667 family = ctx->afi->family;
668
669 /* Re-use the existing target if it's already loaded. */
670 list_for_each_entry(nft_target, &nft_target_list, head) {
671 struct xt_target *target = nft_target->ops.data;
672
673 if (nft_target_cmp(target, tg_name, rev, family)) {
674 if (!try_module_get(target->me))
675 return ERR_PTR(-ENOENT);
676
677 return &nft_target->ops;
678 }
679 }
680
681 target = xt_request_find_target(family, tg_name, rev);
682 if (IS_ERR(target))
683 return ERR_PTR(-ENOENT);
684
685 /* This is the first time we use this target, allocate operations */
686 nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
687 if (nft_target == NULL)
688 return ERR_PTR(-ENOMEM);
689
690 nft_target->ops.type = &nft_target_type;
691 nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
692 nft_target->ops.eval = nft_target_eval;
693 nft_target->ops.init = nft_target_init;
694 nft_target->ops.destroy = nft_target_destroy;
695 nft_target->ops.dump = nft_target_dump;
696 nft_target->ops.validate = nft_target_validate;
697 nft_target->ops.data = target;
698
699 list_add(&nft_target->head, &nft_target_list);
700
701 return &nft_target->ops;
702 }
703
nft_target_release(void)704 static void nft_target_release(void)
705 {
706 struct nft_xt *nft_target, *tmp;
707
708 list_for_each_entry_safe(nft_target, tmp, &nft_target_list, head)
709 kfree(nft_target);
710 }
711
712 static struct nft_expr_type nft_target_type __read_mostly = {
713 .name = "target",
714 .select_ops = nft_target_select_ops,
715 .policy = nft_target_policy,
716 .maxattr = NFTA_TARGET_MAX,
717 .owner = THIS_MODULE,
718 };
719
nft_compat_module_init(void)720 static int __init nft_compat_module_init(void)
721 {
722 int ret;
723
724 ret = nft_register_expr(&nft_match_type);
725 if (ret < 0)
726 return ret;
727
728 ret = nft_register_expr(&nft_target_type);
729 if (ret < 0)
730 goto err_match;
731
732 ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
733 if (ret < 0) {
734 pr_err("nft_compat: cannot register with nfnetlink.\n");
735 goto err_target;
736 }
737
738 pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
739
740 return ret;
741
742 err_target:
743 nft_unregister_expr(&nft_target_type);
744 err_match:
745 nft_unregister_expr(&nft_match_type);
746 return ret;
747 }
748
nft_compat_module_exit(void)749 static void __exit nft_compat_module_exit(void)
750 {
751 nfnetlink_subsys_unregister(&nfnl_compat_subsys);
752 nft_unregister_expr(&nft_target_type);
753 nft_unregister_expr(&nft_match_type);
754 nft_match_release();
755 nft_target_release();
756 }
757
758 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
759
760 module_init(nft_compat_module_init);
761 module_exit(nft_compat_module_exit);
762
763 MODULE_LICENSE("GPL");
764 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
765 MODULE_ALIAS_NFT_EXPR("match");
766 MODULE_ALIAS_NFT_EXPR("target");
767