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v5.14.15
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
  4 *
 
 
 
 
  5 * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/init.h>
 10#include <linux/module.h>
 11#include <linux/netlink.h>
 12#include <linux/netfilter.h>
 13#include <linux/netfilter/nfnetlink.h>
 14#include <linux/netfilter/nf_tables.h>
 15#include <linux/netfilter/nf_tables_compat.h>
 16#include <linux/netfilter/x_tables.h>
 17#include <linux/netfilter_ipv4/ip_tables.h>
 18#include <linux/netfilter_ipv6/ip6_tables.h>
 19#include <linux/netfilter_bridge/ebtables.h>
 20#include <linux/netfilter_arp/arp_tables.h>
 21#include <net/netfilter/nf_tables.h>
 22#include <net/netfilter/nf_log.h>
 23
 24/* Used for matches where *info is larger than X byte */
 25#define NFT_MATCH_LARGE_THRESH	192
 26
 27struct nft_xt_match_priv {
 28	void *info;
 
 
 29};
 30
 31static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
 32						const char *tablename)
 
 
 
 
 
 
 
 
 33{
 34	enum nft_chain_types type = NFT_CHAIN_T_DEFAULT;
 35	const struct nft_chain *chain = ctx->chain;
 36	const struct nft_base_chain *basechain;
 37
 38	if (!tablename ||
 39	    !nft_is_base_chain(chain))
 40		return 0;
 41
 42	basechain = nft_base_chain(chain);
 43	if (strcmp(tablename, "nat") == 0) {
 44		if (ctx->family != NFPROTO_BRIDGE)
 45			type = NFT_CHAIN_T_NAT;
 46		if (basechain->type->type != type)
 47			return -EINVAL;
 48	}
 49
 50	return 0;
 51}
 52
 53union nft_entry {
 54	struct ipt_entry e4;
 55	struct ip6t_entry e6;
 56	struct ebt_entry ebt;
 57	struct arpt_entry arp;
 58};
 59
 60static inline void
 61nft_compat_set_par(struct xt_action_param *par,
 62		   const struct nft_pktinfo *pkt,
 63		   const void *xt, const void *xt_info)
 64{
 65	par->state	= pkt->state;
 66	par->thoff	= nft_thoff(pkt);
 67	par->fragoff	= pkt->fragoff;
 68	par->target	= xt;
 69	par->targinfo	= xt_info;
 70	par->hotdrop	= false;
 71}
 72
 73static void nft_target_eval_xt(const struct nft_expr *expr,
 74			       struct nft_regs *regs,
 75			       const struct nft_pktinfo *pkt)
 76{
 77	void *info = nft_expr_priv(expr);
 78	struct xt_target *target = expr->ops->data;
 79	struct sk_buff *skb = pkt->skb;
 80	struct xt_action_param xt;
 81	int ret;
 82
 83	nft_compat_set_par(&xt, pkt, target, info);
 84
 85	ret = target->target(skb, &xt);
 86
 87	if (xt.hotdrop)
 88		ret = NF_DROP;
 89
 90	switch (ret) {
 91	case XT_CONTINUE:
 92		regs->verdict.code = NFT_CONTINUE;
 93		break;
 94	default:
 95		regs->verdict.code = ret;
 96		break;
 97	}
 98}
 99
100static void nft_target_eval_bridge(const struct nft_expr *expr,
101				   struct nft_regs *regs,
102				   const struct nft_pktinfo *pkt)
103{
104	void *info = nft_expr_priv(expr);
105	struct xt_target *target = expr->ops->data;
106	struct sk_buff *skb = pkt->skb;
107	struct xt_action_param xt;
108	int ret;
109
110	nft_compat_set_par(&xt, pkt, target, info);
111
112	ret = target->target(skb, &xt);
113
114	if (xt.hotdrop)
115		ret = NF_DROP;
116
117	switch (ret) {
118	case EBT_ACCEPT:
119		regs->verdict.code = NF_ACCEPT;
120		break;
121	case EBT_DROP:
122		regs->verdict.code = NF_DROP;
123		break;
124	case EBT_CONTINUE:
125		regs->verdict.code = NFT_CONTINUE;
126		break;
127	case EBT_RETURN:
128		regs->verdict.code = NFT_RETURN;
129		break;
130	default:
131		regs->verdict.code = ret;
132		break;
133	}
134}
135
136static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
137	[NFTA_TARGET_NAME]	= { .type = NLA_NUL_STRING },
138	[NFTA_TARGET_REV]	= { .type = NLA_U32 },
139	[NFTA_TARGET_INFO]	= { .type = NLA_BINARY },
140};
141
142static void
143nft_target_set_tgchk_param(struct xt_tgchk_param *par,
144			   const struct nft_ctx *ctx,
145			   struct xt_target *target, void *info,
146			   union nft_entry *entry, u16 proto, bool inv)
147{
148	par->net	= ctx->net;
149	par->table	= ctx->table->name;
150	switch (ctx->family) {
151	case AF_INET:
152		entry->e4.ip.proto = proto;
153		entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
154		break;
155	case AF_INET6:
156		if (proto)
157			entry->e6.ipv6.flags |= IP6T_F_PROTO;
158
159		entry->e6.ipv6.proto = proto;
160		entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
161		break;
162	case NFPROTO_BRIDGE:
163		entry->ebt.ethproto = (__force __be16)proto;
164		entry->ebt.invflags = inv ? EBT_IPROTO : 0;
165		break;
166	case NFPROTO_ARP:
167		break;
168	}
169	par->entryinfo	= entry;
170	par->target	= target;
171	par->targinfo	= info;
172	if (nft_is_base_chain(ctx->chain)) {
173		const struct nft_base_chain *basechain =
174						nft_base_chain(ctx->chain);
175		const struct nf_hook_ops *ops = &basechain->ops;
176
177		par->hook_mask = 1 << ops->hooknum;
178	} else {
179		par->hook_mask = 0;
180	}
181	par->family	= ctx->family;
182	par->nft_compat = true;
183}
184
185static void target_compat_from_user(struct xt_target *t, void *in, void *out)
186{
187	int pad;
188
189	memcpy(out, in, t->targetsize);
190	pad = XT_ALIGN(t->targetsize) - t->targetsize;
191	if (pad > 0)
192		memset(out + t->targetsize, 0, pad);
193}
194
195static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
196	[NFTA_RULE_COMPAT_PROTO]	= { .type = NLA_U32 },
197	[NFTA_RULE_COMPAT_FLAGS]	= { .type = NLA_U32 },
198};
199
200static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
201{
202	struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
203	u32 flags;
204	int err;
205
206	err = nla_parse_nested_deprecated(tb, NFTA_RULE_COMPAT_MAX, attr,
207					  nft_rule_compat_policy, NULL);
208	if (err < 0)
209		return err;
210
211	if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
212		return -EINVAL;
213
214	flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
215	if (flags & ~NFT_RULE_COMPAT_F_MASK)
216		return -EINVAL;
217	if (flags & NFT_RULE_COMPAT_F_INV)
218		*inv = true;
219
220	*proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
221	return 0;
222}
223
224static void nft_compat_wait_for_destructors(void)
225{
226	/* xtables matches or targets can have side effects, e.g.
227	 * creation/destruction of /proc files.
228	 * The xt ->destroy functions are run asynchronously from
229	 * work queue.  If we have pending invocations we thus
230	 * need to wait for those to finish.
231	 */
232	nf_tables_trans_destroy_flush_work();
233}
234
235static int
236nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
237		const struct nlattr * const tb[])
238{
239	void *info = nft_expr_priv(expr);
240	struct xt_target *target = expr->ops->data;
241	struct xt_tgchk_param par;
242	size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
243	u16 proto = 0;
244	bool inv = false;
245	union nft_entry e = {};
246	int ret;
247
 
 
 
 
248	target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
249
250	if (ctx->nla[NFTA_RULE_COMPAT]) {
251		ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
252		if (ret < 0)
253			return ret;
254	}
255
256	nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
257
258	nft_compat_wait_for_destructors();
259
260	ret = xt_check_target(&par, size, proto, inv);
261	if (ret < 0) {
262		if (ret == -ENOENT) {
263			const char *modname = NULL;
264
265			if (strcmp(target->name, "LOG") == 0)
266				modname = "nf_log_syslog";
267			else if (strcmp(target->name, "NFLOG") == 0)
268				modname = "nfnetlink_log";
269
270			if (modname &&
271			    nft_request_module(ctx->net, "%s", modname) == -EAGAIN)
272				return -EAGAIN;
273		}
274
275		return ret;
276	}
277
278	/* The standard target cannot be used */
279	if (!target->target)
280		return -EINVAL;
 
 
281
282	return 0;
283}
284
285static void __nft_mt_tg_destroy(struct module *me, const struct nft_expr *expr)
286{
287	module_put(me);
288	kfree(expr->ops);
289}
290
291static void
292nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
293{
294	struct xt_target *target = expr->ops->data;
295	void *info = nft_expr_priv(expr);
296	struct module *me = target->me;
297	struct xt_tgdtor_param par;
298
299	par.net = ctx->net;
300	par.target = target;
301	par.targinfo = info;
302	par.family = ctx->family;
303	if (par.target->destroy != NULL)
304		par.target->destroy(&par);
305
306	__nft_mt_tg_destroy(me, expr);
307}
308
309static int nft_extension_dump_info(struct sk_buff *skb, int attr,
310				   const void *info,
311				   unsigned int size, unsigned int user_size)
312{
313	unsigned int info_size, aligned_size = XT_ALIGN(size);
314	struct nlattr *nla;
315
316	nla = nla_reserve(skb, attr, aligned_size);
317	if (!nla)
318		return -1;
319
320	info_size = user_size ? : size;
321	memcpy(nla_data(nla), info, info_size);
322	memset(nla_data(nla) + info_size, 0, aligned_size - info_size);
323
324	return 0;
325}
326
327static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
328{
329	const struct xt_target *target = expr->ops->data;
330	void *info = nft_expr_priv(expr);
331
332	if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
333	    nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
334	    nft_extension_dump_info(skb, NFTA_TARGET_INFO, info,
335				    target->targetsize, target->usersize))
336		goto nla_put_failure;
337
338	return 0;
339
340nla_put_failure:
341	return -1;
342}
343
344static int nft_target_validate(const struct nft_ctx *ctx,
345			       const struct nft_expr *expr,
346			       const struct nft_data **data)
347{
348	struct xt_target *target = expr->ops->data;
349	unsigned int hook_mask = 0;
350	int ret;
351
352	if (nft_is_base_chain(ctx->chain)) {
353		const struct nft_base_chain *basechain =
354						nft_base_chain(ctx->chain);
355		const struct nf_hook_ops *ops = &basechain->ops;
356
357		hook_mask = 1 << ops->hooknum;
358		if (target->hooks && !(hook_mask & target->hooks))
359			return -EINVAL;
360
361		ret = nft_compat_chain_validate_dependency(ctx, target->table);
 
362		if (ret < 0)
363			return ret;
364	}
365	return 0;
366}
367
368static void __nft_match_eval(const struct nft_expr *expr,
369			     struct nft_regs *regs,
370			     const struct nft_pktinfo *pkt,
371			     void *info)
372{
 
373	struct xt_match *match = expr->ops->data;
374	struct sk_buff *skb = pkt->skb;
375	struct xt_action_param xt;
376	bool ret;
377
378	nft_compat_set_par(&xt, pkt, match, info);
379
380	ret = match->match(skb, &xt);
381
382	if (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
397static 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
406static 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
413static 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 */
420static void
421nft_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
462static 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
472static int
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
500static int
501nft_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
507static int
508nft_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
525static void
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
543static void
544nft_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
549static void
550nft_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
558static 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
571nla_put_failure:
572	return -1;
573}
574
575static 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
580static 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
587static 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 (nft_is_base_chain(ctx->chain)) {
596		const struct nft_base_chain *basechain =
597						nft_base_chain(ctx->chain);
598		const struct nf_hook_ops *ops = &basechain->ops;
599
600		hook_mask = 1 << ops->hooknum;
601		if (match->hooks && !(hook_mask & match->hooks))
602			return -EINVAL;
603
604		ret = nft_compat_chain_validate_dependency(ctx, match->table);
 
605		if (ret < 0)
606			return ret;
607	}
608	return 0;
609}
610
611static int
612nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
613		      int event, u16 family, const char *name,
614		      int rev, int target)
615{
616	struct nlmsghdr *nlh;
 
617	unsigned int flags = portid ? NLM_F_MULTI : 0;
618
619	event = nfnl_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
620	nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
621			   NFNETLINK_V0, 0);
622	if (!nlh)
623		goto nlmsg_failure;
624
 
 
 
 
 
625	if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
626	    nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
627	    nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
628		goto nla_put_failure;
629
630	nlmsg_end(skb, nlh);
631	return skb->len;
632
633nlmsg_failure:
634nla_put_failure:
635	nlmsg_cancel(skb, nlh);
636	return -1;
637}
638
639static int nfnl_compat_get_rcu(struct sk_buff *skb,
640			       const struct nfnl_info *info,
641			       const struct nlattr * const tb[])
642{
643	u8 family = info->nfmsg->nfgen_family;
644	const char *name, *fmt;
645	struct sk_buff *skb2;
646	int ret = 0, target;
 
 
 
647	u32 rev;
 
648
649	if (tb[NFTA_COMPAT_NAME] == NULL ||
650	    tb[NFTA_COMPAT_REV] == NULL ||
651	    tb[NFTA_COMPAT_TYPE] == NULL)
652		return -EINVAL;
653
654	name = nla_data(tb[NFTA_COMPAT_NAME]);
655	rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
656	target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
657
658	switch(family) {
 
 
659	case AF_INET:
660		fmt = "ipt_%s";
661		break;
662	case AF_INET6:
663		fmt = "ip6t_%s";
664		break;
665	case NFPROTO_BRIDGE:
666		fmt = "ebt_%s";
667		break;
668	case NFPROTO_ARP:
669		fmt = "arpt_%s";
670		break;
671	default:
672		pr_err("nft_compat: unsupported protocol %d\n", family);
 
673		return -EINVAL;
674	}
675
676	if (!try_module_get(THIS_MODULE))
677		return -EINVAL;
 
678
679	rcu_read_unlock();
680	try_then_request_module(xt_find_revision(family, name, rev, target, &ret),
681				fmt, name);
682	if (ret < 0)
683		goto out_put;
684
685	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
686	if (skb2 == NULL) {
687		ret = -ENOMEM;
688		goto out_put;
689	}
690
691	/* include the best revision for this extension in the message */
692	if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
693				  info->nlh->nlmsg_seq,
694				  NFNL_MSG_TYPE(info->nlh->nlmsg_type),
695				  NFNL_MSG_COMPAT_GET,
696				  family, name, ret, target) <= 0) {
 
697		kfree_skb(skb2);
698		goto out_put;
699	}
700
701	ret = nfnetlink_unicast(skb2, info->net, NETLINK_CB(skb).portid);
702out_put:
703	rcu_read_lock();
704	module_put(THIS_MODULE);
705
706	return ret;
707}
708
709static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
710	[NFTA_COMPAT_NAME]	= { .type = NLA_NUL_STRING,
711				    .len = NFT_COMPAT_NAME_MAX-1 },
712	[NFTA_COMPAT_REV]	= { .type = NLA_U32 },
713	[NFTA_COMPAT_TYPE]	= { .type = NLA_U32 },
714};
715
716static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
717	[NFNL_MSG_COMPAT_GET]	= {
718		.call		= nfnl_compat_get_rcu,
719		.type		= NFNL_CB_RCU,
720		.attr_count	= NFTA_COMPAT_MAX,
721		.policy		= nfnl_compat_policy_get
722	},
723};
724
725static const struct nfnetlink_subsystem nfnl_compat_subsys = {
726	.name		= "nft-compat",
727	.subsys_id	= NFNL_SUBSYS_NFT_COMPAT,
728	.cb_count	= NFNL_MSG_COMPAT_MAX,
729	.cb		= nfnl_nft_compat_cb,
730};
731
 
 
732static struct nft_expr_type nft_match_type;
733
 
 
 
 
 
 
 
734static const struct nft_expr_ops *
735nft_match_select_ops(const struct nft_ctx *ctx,
736		     const struct nlattr * const tb[])
737{
738	struct nft_expr_ops *ops;
739	struct xt_match *match;
740	unsigned int matchsize;
741	char *mt_name;
742	u32 rev, family;
743	int err;
744
745	if (tb[NFTA_MATCH_NAME] == NULL ||
746	    tb[NFTA_MATCH_REV] == NULL ||
747	    tb[NFTA_MATCH_INFO] == NULL)
748		return ERR_PTR(-EINVAL);
749
750	mt_name = nla_data(tb[NFTA_MATCH_NAME]);
751	rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
752	family = ctx->family;
 
 
 
 
 
 
 
 
 
 
 
 
 
753
754	match = xt_request_find_match(family, mt_name, rev);
755	if (IS_ERR(match))
756		return ERR_PTR(-ENOENT);
757
758	if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
759		err = -EINVAL;
760		goto err;
761	}
762
763	ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
764	if (!ops) {
 
765		err = -ENOMEM;
766		goto err;
767	}
768
769	ops->type = &nft_match_type;
770	ops->eval = nft_match_eval;
771	ops->init = nft_match_init;
772	ops->destroy = nft_match_destroy;
773	ops->dump = nft_match_dump;
774	ops->validate = nft_match_validate;
775	ops->data = match;
776
777	matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
778	if (matchsize > NFT_MATCH_LARGE_THRESH) {
779		matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
780
781		ops->eval = nft_match_large_eval;
782		ops->init = nft_match_large_init;
783		ops->destroy = nft_match_large_destroy;
784		ops->dump = nft_match_large_dump;
785	}
786
787	ops->size = matchsize;
788
789	return ops;
790err:
791	module_put(match->me);
792	return ERR_PTR(err);
793}
794
795static void nft_match_release_ops(const struct nft_expr_ops *ops)
796{
797	struct xt_match *match = ops->data;
798
799	module_put(match->me);
800	kfree(ops);
801}
802
803static struct nft_expr_type nft_match_type __read_mostly = {
804	.name		= "match",
805	.select_ops	= nft_match_select_ops,
806	.release_ops	= nft_match_release_ops,
807	.policy		= nft_match_policy,
808	.maxattr	= NFTA_MATCH_MAX,
809	.owner		= THIS_MODULE,
810};
811
 
 
812static struct nft_expr_type nft_target_type;
813
 
 
 
 
 
 
 
814static const struct nft_expr_ops *
815nft_target_select_ops(const struct nft_ctx *ctx,
816		      const struct nlattr * const tb[])
817{
818	struct nft_expr_ops *ops;
819	struct xt_target *target;
820	char *tg_name;
821	u32 rev, family;
822	int err;
823
824	if (tb[NFTA_TARGET_NAME] == NULL ||
825	    tb[NFTA_TARGET_REV] == NULL ||
826	    tb[NFTA_TARGET_INFO] == NULL)
827		return ERR_PTR(-EINVAL);
828
829	tg_name = nla_data(tb[NFTA_TARGET_NAME]);
830	rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
831	family = ctx->family;
832
833	if (strcmp(tg_name, XT_ERROR_TARGET) == 0 ||
834	    strcmp(tg_name, XT_STANDARD_TARGET) == 0 ||
835	    strcmp(tg_name, "standard") == 0)
836		return ERR_PTR(-EINVAL);
 
 
 
 
 
 
 
 
837
838	target = xt_request_find_target(family, tg_name, rev);
839	if (IS_ERR(target))
840		return ERR_PTR(-ENOENT);
841
842	if (!target->target) {
843		err = -EINVAL;
844		goto err;
845	}
846
847	if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
848		err = -EINVAL;
849		goto err;
850	}
851
852	ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
853	if (!ops) {
 
854		err = -ENOMEM;
855		goto err;
856	}
857
858	ops->type = &nft_target_type;
859	ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
860	ops->init = nft_target_init;
861	ops->destroy = nft_target_destroy;
862	ops->dump = nft_target_dump;
863	ops->validate = nft_target_validate;
864	ops->data = target;
 
865
866	if (family == NFPROTO_BRIDGE)
867		ops->eval = nft_target_eval_bridge;
868	else
869		ops->eval = nft_target_eval_xt;
 
 
870
871	return ops;
872err:
873	module_put(target->me);
874	return ERR_PTR(err);
875}
876
877static void nft_target_release_ops(const struct nft_expr_ops *ops)
878{
879	struct xt_target *target = ops->data;
880
881	module_put(target->me);
882	kfree(ops);
883}
884
885static struct nft_expr_type nft_target_type __read_mostly = {
886	.name		= "target",
887	.select_ops	= nft_target_select_ops,
888	.release_ops	= nft_target_release_ops,
889	.policy		= nft_target_policy,
890	.maxattr	= NFTA_TARGET_MAX,
891	.owner		= THIS_MODULE,
892};
893
894static int __init nft_compat_module_init(void)
895{
896	int ret;
897
898	ret = nft_register_expr(&nft_match_type);
899	if (ret < 0)
900		return ret;
901
902	ret = nft_register_expr(&nft_target_type);
903	if (ret < 0)
904		goto err_match;
905
906	ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
907	if (ret < 0) {
908		pr_err("nft_compat: cannot register with nfnetlink.\n");
909		goto err_target;
910	}
911
 
 
912	return ret;
 
913err_target:
914	nft_unregister_expr(&nft_target_type);
915err_match:
916	nft_unregister_expr(&nft_match_type);
917	return ret;
918}
919
920static void __exit nft_compat_module_exit(void)
921{
922	nfnetlink_subsys_unregister(&nfnl_compat_subsys);
923	nft_unregister_expr(&nft_target_type);
924	nft_unregister_expr(&nft_match_type);
925}
926
927MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
928
929module_init(nft_compat_module_init);
930module_exit(nft_compat_module_exit);
931
932MODULE_LICENSE("GPL");
933MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
934MODULE_ALIAS_NFT_EXPR("match");
935MODULE_ALIAS_NFT_EXPR("target");
936MODULE_DESCRIPTION("x_tables over nftables support");
v4.10.11
 
  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
 26struct nft_xt {
 27	struct list_head	head;
 28	struct nft_expr_ops	ops;
 29	unsigned int		refcnt;
 30};
 31
 32static 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
 40static 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 || !(chain->flags & NFT_BASE_CHAIN))
 
 46		return 0;
 47
 48	basechain = nft_base_chain(chain);
 49	if (strcmp(tablename, "nat") == 0 &&
 50	    basechain->type->type != NFT_CHAIN_T_NAT)
 51		return -EINVAL;
 
 
 
 52
 53	return 0;
 54}
 55
 56union nft_entry {
 57	struct ipt_entry e4;
 58	struct ip6t_entry e6;
 59	struct ebt_entry ebt;
 60	struct arpt_entry arp;
 61};
 62
 63static inline void
 64nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
 65{
 
 
 
 
 
 66	par->target	= xt;
 67	par->targinfo	= xt_info;
 68	par->hotdrop	= false;
 69}
 70
 71static void nft_target_eval_xt(const struct nft_expr *expr,
 72			       struct nft_regs *regs,
 73			       const struct nft_pktinfo *pkt)
 74{
 75	void *info = nft_expr_priv(expr);
 76	struct xt_target *target = expr->ops->data;
 77	struct sk_buff *skb = pkt->skb;
 
 78	int ret;
 79
 80	nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
 81
 82	ret = target->target(skb, &pkt->xt);
 83
 84	if (pkt->xt.hotdrop)
 85		ret = NF_DROP;
 86
 87	switch (ret) {
 88	case XT_CONTINUE:
 89		regs->verdict.code = NFT_CONTINUE;
 90		break;
 91	default:
 92		regs->verdict.code = ret;
 93		break;
 94	}
 95}
 96
 97static void nft_target_eval_bridge(const struct nft_expr *expr,
 98				   struct nft_regs *regs,
 99				   const struct nft_pktinfo *pkt)
100{
101	void *info = nft_expr_priv(expr);
102	struct xt_target *target = expr->ops->data;
103	struct sk_buff *skb = pkt->skb;
 
104	int ret;
105
106	nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
107
108	ret = target->target(skb, &pkt->xt);
109
110	if (pkt->xt.hotdrop)
111		ret = NF_DROP;
112
113	switch (ret) {
114	case EBT_ACCEPT:
115		regs->verdict.code = NF_ACCEPT;
116		break;
117	case EBT_DROP:
118		regs->verdict.code = NF_DROP;
119		break;
120	case EBT_CONTINUE:
121		regs->verdict.code = NFT_CONTINUE;
122		break;
123	case EBT_RETURN:
124		regs->verdict.code = NFT_RETURN;
125		break;
126	default:
127		regs->verdict.code = ret;
128		break;
129	}
130}
131
132static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
133	[NFTA_TARGET_NAME]	= { .type = NLA_NUL_STRING },
134	[NFTA_TARGET_REV]	= { .type = NLA_U32 },
135	[NFTA_TARGET_INFO]	= { .type = NLA_BINARY },
136};
137
138static void
139nft_target_set_tgchk_param(struct xt_tgchk_param *par,
140			   const struct nft_ctx *ctx,
141			   struct xt_target *target, void *info,
142			   union nft_entry *entry, u16 proto, bool inv)
143{
144	par->net	= ctx->net;
145	par->table	= ctx->table->name;
146	switch (ctx->afi->family) {
147	case AF_INET:
148		entry->e4.ip.proto = proto;
149		entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
150		break;
151	case AF_INET6:
152		if (proto)
153			entry->e6.ipv6.flags |= IP6T_F_PROTO;
154
155		entry->e6.ipv6.proto = proto;
156		entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
157		break;
158	case NFPROTO_BRIDGE:
159		entry->ebt.ethproto = (__force __be16)proto;
160		entry->ebt.invflags = inv ? EBT_IPROTO : 0;
161		break;
162	case NFPROTO_ARP:
163		break;
164	}
165	par->entryinfo	= entry;
166	par->target	= target;
167	par->targinfo	= info;
168	if (ctx->chain->flags & NFT_BASE_CHAIN) {
169		const struct nft_base_chain *basechain =
170						nft_base_chain(ctx->chain);
171		const struct nf_hook_ops *ops = &basechain->ops[0];
172
173		par->hook_mask = 1 << ops->hooknum;
174	} else {
175		par->hook_mask = 0;
176	}
177	par->family	= ctx->afi->family;
178	par->nft_compat = true;
179}
180
181static void target_compat_from_user(struct xt_target *t, void *in, void *out)
182{
183	int pad;
184
185	memcpy(out, in, t->targetsize);
186	pad = XT_ALIGN(t->targetsize) - t->targetsize;
187	if (pad > 0)
188		memset(out + t->targetsize, 0, pad);
189}
190
191static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
192	[NFTA_RULE_COMPAT_PROTO]	= { .type = NLA_U32 },
193	[NFTA_RULE_COMPAT_FLAGS]	= { .type = NLA_U32 },
194};
195
196static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
197{
198	struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
199	u32 flags;
200	int err;
201
202	err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
203			       nft_rule_compat_policy);
204	if (err < 0)
205		return err;
206
207	if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
208		return -EINVAL;
209
210	flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
211	if (flags & ~NFT_RULE_COMPAT_F_MASK)
212		return -EINVAL;
213	if (flags & NFT_RULE_COMPAT_F_INV)
214		*inv = true;
215
216	*proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
217	return 0;
218}
219
 
 
 
 
 
 
 
 
 
 
 
220static int
221nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
222		const struct nlattr * const tb[])
223{
224	void *info = nft_expr_priv(expr);
225	struct xt_target *target = expr->ops->data;
226	struct xt_tgchk_param par;
227	size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
228	u16 proto = 0;
229	bool inv = false;
230	union nft_entry e = {};
231	int ret;
232
233	ret = nft_compat_chain_validate_dependency(target->table, ctx->chain);
234	if (ret < 0)
235		goto err;
236
237	target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
238
239	if (ctx->nla[NFTA_RULE_COMPAT]) {
240		ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
241		if (ret < 0)
242			goto err;
243	}
244
245	nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
246
 
 
247	ret = xt_check_target(&par, size, proto, inv);
248	if (ret < 0)
249		goto err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
250
251	/* The standard target cannot be used */
252	if (target->target == NULL) {
253		ret = -EINVAL;
254		goto err;
255	}
256
257	return 0;
258err:
259	module_put(target->me);
260	return ret;
 
 
 
261}
262
263static void
264nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
265{
266	struct xt_target *target = expr->ops->data;
267	void *info = nft_expr_priv(expr);
 
268	struct xt_tgdtor_param par;
269
270	par.net = ctx->net;
271	par.target = target;
272	par.targinfo = info;
273	par.family = ctx->afi->family;
274	if (par.target->destroy != NULL)
275		par.target->destroy(&par);
276
277	nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
278	module_put(target->me);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
279}
280
281static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
282{
283	const struct xt_target *target = expr->ops->data;
284	void *info = nft_expr_priv(expr);
285
286	if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
287	    nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
288	    nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
 
289		goto nla_put_failure;
290
291	return 0;
292
293nla_put_failure:
294	return -1;
295}
296
297static int nft_target_validate(const struct nft_ctx *ctx,
298			       const struct nft_expr *expr,
299			       const struct nft_data **data)
300{
301	struct xt_target *target = expr->ops->data;
302	unsigned int hook_mask = 0;
303	int ret;
304
305	if (ctx->chain->flags & NFT_BASE_CHAIN) {
306		const struct nft_base_chain *basechain =
307						nft_base_chain(ctx->chain);
308		const struct nf_hook_ops *ops = &basechain->ops[0];
309
310		hook_mask = 1 << ops->hooknum;
311		if (!(hook_mask & target->hooks))
312			return -EINVAL;
313
314		ret = nft_compat_chain_validate_dependency(target->table,
315							   ctx->chain);
316		if (ret < 0)
317			return ret;
318	}
319	return 0;
320}
321
322static void nft_match_eval(const struct nft_expr *expr,
323			   struct nft_regs *regs,
324			   const struct nft_pktinfo *pkt)
 
325{
326	void *info = nft_expr_priv(expr);
327	struct xt_match *match = expr->ops->data;
328	struct sk_buff *skb = pkt->skb;
 
329	bool ret;
330
331	nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
332
333	ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
334
335	if (pkt->xt.hotdrop) {
336		regs->verdict.code = NF_DROP;
337		return;
338	}
339
340	switch (ret ? 1 : 0) {
341	case 1:
342		regs->verdict.code = NFT_CONTINUE;
343		break;
344	case 0:
345		regs->verdict.code = NFT_BREAK;
346		break;
347	}
348}
349
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
350static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
351	[NFTA_MATCH_NAME]	= { .type = NLA_NUL_STRING },
352	[NFTA_MATCH_REV]	= { .type = NLA_U32 },
353	[NFTA_MATCH_INFO]	= { .type = NLA_BINARY },
354};
355
356/* struct xt_mtchk_param and xt_tgchk_param look very similar */
357static void
358nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
359			  struct xt_match *match, void *info,
360			  union nft_entry *entry, u16 proto, bool inv)
361{
362	par->net	= ctx->net;
363	par->table	= ctx->table->name;
364	switch (ctx->afi->family) {
365	case AF_INET:
366		entry->e4.ip.proto = proto;
367		entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
368		break;
369	case AF_INET6:
370		if (proto)
371			entry->e6.ipv6.flags |= IP6T_F_PROTO;
372
373		entry->e6.ipv6.proto = proto;
374		entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
375		break;
376	case NFPROTO_BRIDGE:
377		entry->ebt.ethproto = (__force __be16)proto;
378		entry->ebt.invflags = inv ? EBT_IPROTO : 0;
379		break;
380	case NFPROTO_ARP:
381		break;
382	}
383	par->entryinfo	= entry;
384	par->match	= match;
385	par->matchinfo	= info;
386	if (ctx->chain->flags & NFT_BASE_CHAIN) {
387		const struct nft_base_chain *basechain =
388						nft_base_chain(ctx->chain);
389		const struct nf_hook_ops *ops = &basechain->ops[0];
390
391		par->hook_mask = 1 << ops->hooknum;
392	} else {
393		par->hook_mask = 0;
394	}
395	par->family	= ctx->afi->family;
396	par->nft_compat = true;
397}
398
399static void match_compat_from_user(struct xt_match *m, void *in, void *out)
400{
401	int pad;
402
403	memcpy(out, in, m->matchsize);
404	pad = XT_ALIGN(m->matchsize) - m->matchsize;
405	if (pad > 0)
406		memset(out + m->matchsize, 0, pad);
407}
408
409static int
410nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
411		const struct nlattr * const tb[])
 
412{
413	void *info = nft_expr_priv(expr);
414	struct xt_match *match = expr->ops->data;
415	struct xt_mtchk_param par;
416	size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
417	u16 proto = 0;
418	bool inv = false;
419	union nft_entry e = {};
420	int ret;
421
422	ret = nft_compat_chain_validate_dependency(match->table, ctx->chain);
423	if (ret < 0)
424		goto err;
425
426	match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
427
428	if (ctx->nla[NFTA_RULE_COMPAT]) {
429		ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
430		if (ret < 0)
431			goto err;
432	}
433
434	nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
435
436	ret = xt_check_match(&par, size, proto, inv);
437	if (ret < 0)
438		goto err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
439
440	return 0;
441err:
442	module_put(match->me);
443	return ret;
444}
445
446static void
447nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 
448{
449	struct xt_match *match = expr->ops->data;
450	void *info = nft_expr_priv(expr);
451	struct xt_mtdtor_param par;
452
453	par.net = ctx->net;
454	par.match = match;
455	par.matchinfo = info;
456	par.family = ctx->afi->family;
457	if (par.match->destroy != NULL)
458		par.match->destroy(&par);
459
460	nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
461	module_put(match->me);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
462}
463
464static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
 
465{
466	void *info = nft_expr_priv(expr);
467	struct xt_match *match = expr->ops->data;
468
469	if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
470	    nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
471	    nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
 
472		goto nla_put_failure;
473
474	return 0;
475
476nla_put_failure:
477	return -1;
478}
479
 
 
 
 
 
 
 
 
 
 
 
 
480static int nft_match_validate(const struct nft_ctx *ctx,
481			      const struct nft_expr *expr,
482			      const struct nft_data **data)
483{
484	struct xt_match *match = expr->ops->data;
485	unsigned int hook_mask = 0;
486	int ret;
487
488	if (ctx->chain->flags & NFT_BASE_CHAIN) {
489		const struct nft_base_chain *basechain =
490						nft_base_chain(ctx->chain);
491		const struct nf_hook_ops *ops = &basechain->ops[0];
492
493		hook_mask = 1 << ops->hooknum;
494		if (!(hook_mask & match->hooks))
495			return -EINVAL;
496
497		ret = nft_compat_chain_validate_dependency(match->table,
498							   ctx->chain);
499		if (ret < 0)
500			return ret;
501	}
502	return 0;
503}
504
505static int
506nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
507		      int event, u16 family, const char *name,
508		      int rev, int target)
509{
510	struct nlmsghdr *nlh;
511	struct nfgenmsg *nfmsg;
512	unsigned int flags = portid ? NLM_F_MULTI : 0;
513
514	event |= NFNL_SUBSYS_NFT_COMPAT << 8;
515	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
516	if (nlh == NULL)
 
517		goto nlmsg_failure;
518
519	nfmsg = nlmsg_data(nlh);
520	nfmsg->nfgen_family = family;
521	nfmsg->version = NFNETLINK_V0;
522	nfmsg->res_id = 0;
523
524	if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
525	    nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
526	    nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
527		goto nla_put_failure;
528
529	nlmsg_end(skb, nlh);
530	return skb->len;
531
532nlmsg_failure:
533nla_put_failure:
534	nlmsg_cancel(skb, nlh);
535	return -1;
536}
537
538static int nfnl_compat_get(struct net *net, struct sock *nfnl,
539			   struct sk_buff *skb, const struct nlmsghdr *nlh,
540			   const struct nlattr * const tb[])
541{
 
 
 
542	int ret = 0, target;
543	struct nfgenmsg *nfmsg;
544	const char *fmt;
545	const char *name;
546	u32 rev;
547	struct sk_buff *skb2;
548
549	if (tb[NFTA_COMPAT_NAME] == NULL ||
550	    tb[NFTA_COMPAT_REV] == NULL ||
551	    tb[NFTA_COMPAT_TYPE] == NULL)
552		return -EINVAL;
553
554	name = nla_data(tb[NFTA_COMPAT_NAME]);
555	rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
556	target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
557
558	nfmsg = nlmsg_data(nlh);
559
560	switch(nfmsg->nfgen_family) {
561	case AF_INET:
562		fmt = "ipt_%s";
563		break;
564	case AF_INET6:
565		fmt = "ip6t_%s";
566		break;
567	case NFPROTO_BRIDGE:
568		fmt = "ebt_%s";
569		break;
570	case NFPROTO_ARP:
571		fmt = "arpt_%s";
572		break;
573	default:
574		pr_err("nft_compat: unsupported protocol %d\n",
575			nfmsg->nfgen_family);
576		return -EINVAL;
577	}
578
579	try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
580						 rev, target, &ret),
581						 fmt, name);
582
 
 
 
583	if (ret < 0)
584		return ret;
585
586	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
587	if (skb2 == NULL)
588		return -ENOMEM;
 
 
589
590	/* include the best revision for this extension in the message */
591	if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
592				  nlh->nlmsg_seq,
593				  NFNL_MSG_TYPE(nlh->nlmsg_type),
594				  NFNL_MSG_COMPAT_GET,
595				  nfmsg->nfgen_family,
596				  name, ret, target) <= 0) {
597		kfree_skb(skb2);
598		return -ENOSPC;
599	}
600
601	ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
602				MSG_DONTWAIT);
603	if (ret > 0)
604		ret = 0;
605
606	return ret == -EAGAIN ? -ENOBUFS : ret;
607}
608
609static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
610	[NFTA_COMPAT_NAME]	= { .type = NLA_NUL_STRING,
611				    .len = NFT_COMPAT_NAME_MAX-1 },
612	[NFTA_COMPAT_REV]	= { .type = NLA_U32 },
613	[NFTA_COMPAT_TYPE]	= { .type = NLA_U32 },
614};
615
616static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
617	[NFNL_MSG_COMPAT_GET]		= { .call = nfnl_compat_get,
618					    .attr_count = NFTA_COMPAT_MAX,
619					    .policy = nfnl_compat_policy_get },
 
 
 
620};
621
622static const struct nfnetlink_subsystem nfnl_compat_subsys = {
623	.name		= "nft-compat",
624	.subsys_id	= NFNL_SUBSYS_NFT_COMPAT,
625	.cb_count	= NFNL_MSG_COMPAT_MAX,
626	.cb		= nfnl_nft_compat_cb,
627};
628
629static LIST_HEAD(nft_match_list);
630
631static struct nft_expr_type nft_match_type;
632
633static bool nft_match_cmp(const struct xt_match *match,
634			  const char *name, u32 rev, u32 family)
635{
636	return strcmp(match->name, name) == 0 && match->revision == rev &&
637	       (match->family == NFPROTO_UNSPEC || match->family == family);
638}
639
640static const struct nft_expr_ops *
641nft_match_select_ops(const struct nft_ctx *ctx,
642		     const struct nlattr * const tb[])
643{
644	struct nft_xt *nft_match;
645	struct xt_match *match;
 
646	char *mt_name;
647	u32 rev, family;
648	int err;
649
650	if (tb[NFTA_MATCH_NAME] == NULL ||
651	    tb[NFTA_MATCH_REV] == NULL ||
652	    tb[NFTA_MATCH_INFO] == NULL)
653		return ERR_PTR(-EINVAL);
654
655	mt_name = nla_data(tb[NFTA_MATCH_NAME]);
656	rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
657	family = ctx->afi->family;
658
659	/* Re-use the existing match if it's already loaded. */
660	list_for_each_entry(nft_match, &nft_match_list, head) {
661		struct xt_match *match = nft_match->ops.data;
662
663		if (nft_match_cmp(match, mt_name, rev, family)) {
664			if (!try_module_get(match->me))
665				return ERR_PTR(-ENOENT);
666
667			nft_match->refcnt++;
668			return &nft_match->ops;
669		}
670	}
671
672	match = xt_request_find_match(family, mt_name, rev);
673	if (IS_ERR(match))
674		return ERR_PTR(-ENOENT);
675
676	if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
677		err = -EINVAL;
678		goto err;
679	}
680
681	/* This is the first time we use this match, allocate operations */
682	nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
683	if (nft_match == NULL) {
684		err = -ENOMEM;
685		goto err;
686	}
687
688	nft_match->refcnt = 1;
689	nft_match->ops.type = &nft_match_type;
690	nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
691	nft_match->ops.eval = nft_match_eval;
692	nft_match->ops.init = nft_match_init;
693	nft_match->ops.destroy = nft_match_destroy;
694	nft_match->ops.dump = nft_match_dump;
695	nft_match->ops.validate = nft_match_validate;
696	nft_match->ops.data = match;
 
 
 
 
 
 
 
 
697
698	list_add(&nft_match->head, &nft_match_list);
699
700	return &nft_match->ops;
701err:
702	module_put(match->me);
703	return ERR_PTR(err);
704}
705
 
 
 
 
 
 
 
 
706static struct nft_expr_type nft_match_type __read_mostly = {
707	.name		= "match",
708	.select_ops	= nft_match_select_ops,
 
709	.policy		= nft_match_policy,
710	.maxattr	= NFTA_MATCH_MAX,
711	.owner		= THIS_MODULE,
712};
713
714static LIST_HEAD(nft_target_list);
715
716static struct nft_expr_type nft_target_type;
717
718static bool nft_target_cmp(const struct xt_target *tg,
719			   const char *name, u32 rev, u32 family)
720{
721	return strcmp(tg->name, name) == 0 && tg->revision == rev &&
722	       (tg->family == NFPROTO_UNSPEC || tg->family == family);
723}
724
725static const struct nft_expr_ops *
726nft_target_select_ops(const struct nft_ctx *ctx,
727		      const struct nlattr * const tb[])
728{
729	struct nft_xt *nft_target;
730	struct xt_target *target;
731	char *tg_name;
732	u32 rev, family;
733	int err;
734
735	if (tb[NFTA_TARGET_NAME] == NULL ||
736	    tb[NFTA_TARGET_REV] == NULL ||
737	    tb[NFTA_TARGET_INFO] == NULL)
738		return ERR_PTR(-EINVAL);
739
740	tg_name = nla_data(tb[NFTA_TARGET_NAME]);
741	rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
742	family = ctx->afi->family;
743
744	/* Re-use the existing target if it's already loaded. */
745	list_for_each_entry(nft_target, &nft_target_list, head) {
746		struct xt_target *target = nft_target->ops.data;
747
748		if (nft_target_cmp(target, tg_name, rev, family)) {
749			if (!try_module_get(target->me))
750				return ERR_PTR(-ENOENT);
751
752			nft_target->refcnt++;
753			return &nft_target->ops;
754		}
755	}
756
757	target = xt_request_find_target(family, tg_name, rev);
758	if (IS_ERR(target))
759		return ERR_PTR(-ENOENT);
760
 
 
 
 
 
761	if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
762		err = -EINVAL;
763		goto err;
764	}
765
766	/* This is the first time we use this target, allocate operations */
767	nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
768	if (nft_target == NULL) {
769		err = -ENOMEM;
770		goto err;
771	}
772
773	nft_target->refcnt = 1;
774	nft_target->ops.type = &nft_target_type;
775	nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
776	nft_target->ops.init = nft_target_init;
777	nft_target->ops.destroy = nft_target_destroy;
778	nft_target->ops.dump = nft_target_dump;
779	nft_target->ops.validate = nft_target_validate;
780	nft_target->ops.data = target;
781
782	if (family == NFPROTO_BRIDGE)
783		nft_target->ops.eval = nft_target_eval_bridge;
784	else
785		nft_target->ops.eval = nft_target_eval_xt;
786
787	list_add(&nft_target->head, &nft_target_list);
788
789	return &nft_target->ops;
790err:
791	module_put(target->me);
792	return ERR_PTR(err);
793}
794
 
 
 
 
 
 
 
 
795static struct nft_expr_type nft_target_type __read_mostly = {
796	.name		= "target",
797	.select_ops	= nft_target_select_ops,
 
798	.policy		= nft_target_policy,
799	.maxattr	= NFTA_TARGET_MAX,
800	.owner		= THIS_MODULE,
801};
802
803static int __init nft_compat_module_init(void)
804{
805	int ret;
806
807	ret = nft_register_expr(&nft_match_type);
808	if (ret < 0)
809		return ret;
810
811	ret = nft_register_expr(&nft_target_type);
812	if (ret < 0)
813		goto err_match;
814
815	ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
816	if (ret < 0) {
817		pr_err("nft_compat: cannot register with nfnetlink.\n");
818		goto err_target;
819	}
820
821	pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
822
823	return ret;
824
825err_target:
826	nft_unregister_expr(&nft_target_type);
827err_match:
828	nft_unregister_expr(&nft_match_type);
829	return ret;
830}
831
832static void __exit nft_compat_module_exit(void)
833{
834	nfnetlink_subsys_unregister(&nfnl_compat_subsys);
835	nft_unregister_expr(&nft_target_type);
836	nft_unregister_expr(&nft_match_type);
837}
838
839MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
840
841module_init(nft_compat_module_init);
842module_exit(nft_compat_module_exit);
843
844MODULE_LICENSE("GPL");
845MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
846MODULE_ALIAS_NFT_EXPR("match");
847MODULE_ALIAS_NFT_EXPR("target");