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