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[releases.git] / bridge / netfilter / ebtables.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ebtables
4  *
5  *  Author:
6  *  Bart De Schuymer            <bdschuym@pandora.be>
7  *
8  *  ebtables.c,v 2.0, July, 2002
9  *
10  *  This code is strongly inspired by the iptables code which is
11  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
12  */
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/kmod.h>
15 #include <linux/module.h>
16 #include <linux/vmalloc.h>
17 #include <linux/netfilter/x_tables.h>
18 #include <linux/netfilter_bridge/ebtables.h>
19 #include <linux/spinlock.h>
20 #include <linux/mutex.h>
21 #include <linux/slab.h>
22 #include <linux/uaccess.h>
23 #include <linux/smp.h>
24 #include <linux/cpumask.h>
25 #include <linux/audit.h>
26 #include <net/sock.h>
27 #include <net/netns/generic.h>
28 /* needed for logical [in,out]-dev filtering */
29 #include "../br_private.h"
30
31 /* Each cpu has its own set of counters, so there is no need for write_lock in
32  * the softirq
33  * For reading or updating the counters, the user context needs to
34  * get a write_lock
35  */
36
37 /* The size of each set of counters is altered to get cache alignment */
38 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
39 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
40 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
41                                  COUNTER_OFFSET(n) * cpu))
42
43 struct ebt_pernet {
44         struct list_head tables;
45 };
46
47 struct ebt_template {
48         struct list_head list;
49         char name[EBT_TABLE_MAXNAMELEN];
50         struct module *owner;
51         /* called when table is needed in the given netns */
52         int (*table_init)(struct net *net);
53 };
54
55 static unsigned int ebt_pernet_id __read_mostly;
56 static LIST_HEAD(template_tables);
57 static DEFINE_MUTEX(ebt_mutex);
58
59 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
60 static void ebt_standard_compat_from_user(void *dst, const void *src)
61 {
62         int v = *(compat_int_t *)src;
63
64         if (v >= 0)
65                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
66         memcpy(dst, &v, sizeof(v));
67 }
68
69 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
70 {
71         compat_int_t cv = *(int *)src;
72
73         if (cv >= 0)
74                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
75         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
76 }
77 #endif
78
79
80 static struct xt_target ebt_standard_target = {
81         .name       = "standard",
82         .revision   = 0,
83         .family     = NFPROTO_BRIDGE,
84         .targetsize = sizeof(int),
85 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
86         .compatsize = sizeof(compat_int_t),
87         .compat_from_user = ebt_standard_compat_from_user,
88         .compat_to_user =  ebt_standard_compat_to_user,
89 #endif
90 };
91
92 static inline int
93 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
94                struct xt_action_param *par)
95 {
96         par->target   = w->u.watcher;
97         par->targinfo = w->data;
98         w->u.watcher->target(skb, par);
99         /* watchers don't give a verdict */
100         return 0;
101 }
102
103 static inline int
104 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
105              struct xt_action_param *par)
106 {
107         par->match     = m->u.match;
108         par->matchinfo = m->data;
109         return !m->u.match->match(skb, par);
110 }
111
112 static inline int
113 ebt_dev_check(const char *entry, const struct net_device *device)
114 {
115         int i = 0;
116         const char *devname;
117
118         if (*entry == '\0')
119                 return 0;
120         if (!device)
121                 return 1;
122         devname = device->name;
123         /* 1 is the wildcard token */
124         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
125                 i++;
126         return devname[i] != entry[i] && entry[i] != 1;
127 }
128
129 /* process standard matches */
130 static inline int
131 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
132                 const struct net_device *in, const struct net_device *out)
133 {
134         const struct ethhdr *h = eth_hdr(skb);
135         const struct net_bridge_port *p;
136         __be16 ethproto;
137
138         if (skb_vlan_tag_present(skb))
139                 ethproto = htons(ETH_P_8021Q);
140         else
141                 ethproto = h->h_proto;
142
143         if (e->bitmask & EBT_802_3) {
144                 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
145                         return 1;
146         } else if (!(e->bitmask & EBT_NOPROTO) &&
147                    NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
148                 return 1;
149
150         if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
151                 return 1;
152         if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
153                 return 1;
154         /* rcu_read_lock()ed by nf_hook_thresh */
155         if (in && (p = br_port_get_rcu(in)) != NULL &&
156             NF_INVF(e, EBT_ILOGICALIN,
157                     ebt_dev_check(e->logical_in, p->br->dev)))
158                 return 1;
159         if (out && (p = br_port_get_rcu(out)) != NULL &&
160             NF_INVF(e, EBT_ILOGICALOUT,
161                     ebt_dev_check(e->logical_out, p->br->dev)))
162                 return 1;
163
164         if (e->bitmask & EBT_SOURCEMAC) {
165                 if (NF_INVF(e, EBT_ISOURCE,
166                             !ether_addr_equal_masked(h->h_source, e->sourcemac,
167                                                      e->sourcemsk)))
168                         return 1;
169         }
170         if (e->bitmask & EBT_DESTMAC) {
171                 if (NF_INVF(e, EBT_IDEST,
172                             !ether_addr_equal_masked(h->h_dest, e->destmac,
173                                                      e->destmsk)))
174                         return 1;
175         }
176         return 0;
177 }
178
179 static inline
180 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
181 {
182         return (void *)entry + entry->next_offset;
183 }
184
185 static inline const struct ebt_entry_target *
186 ebt_get_target_c(const struct ebt_entry *e)
187 {
188         return ebt_get_target((struct ebt_entry *)e);
189 }
190
191 /* Do some firewalling */
192 unsigned int ebt_do_table(void *priv, struct sk_buff *skb,
193                           const struct nf_hook_state *state)
194 {
195         struct ebt_table *table = priv;
196         unsigned int hook = state->hook;
197         int i, nentries;
198         struct ebt_entry *point;
199         struct ebt_counter *counter_base, *cb_base;
200         const struct ebt_entry_target *t;
201         int verdict, sp = 0;
202         struct ebt_chainstack *cs;
203         struct ebt_entries *chaininfo;
204         const char *base;
205         const struct ebt_table_info *private;
206         struct xt_action_param acpar;
207
208         acpar.state   = state;
209         acpar.hotdrop = false;
210
211         read_lock_bh(&table->lock);
212         private = table->private;
213         cb_base = COUNTER_BASE(private->counters, private->nentries,
214            smp_processor_id());
215         if (private->chainstack)
216                 cs = private->chainstack[smp_processor_id()];
217         else
218                 cs = NULL;
219         chaininfo = private->hook_entry[hook];
220         nentries = private->hook_entry[hook]->nentries;
221         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
222         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
223         /* base for chain jumps */
224         base = private->entries;
225         i = 0;
226         while (i < nentries) {
227                 if (ebt_basic_match(point, skb, state->in, state->out))
228                         goto letscontinue;
229
230                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
231                         goto letscontinue;
232                 if (acpar.hotdrop) {
233                         read_unlock_bh(&table->lock);
234                         return NF_DROP;
235                 }
236
237                 ADD_COUNTER(*(counter_base + i), skb->len, 1);
238
239                 /* these should only watch: not modify, nor tell us
240                  * what to do with the packet
241                  */
242                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
243
244                 t = ebt_get_target_c(point);
245                 /* standard target */
246                 if (!t->u.target->target)
247                         verdict = ((struct ebt_standard_target *)t)->verdict;
248                 else {
249                         acpar.target   = t->u.target;
250                         acpar.targinfo = t->data;
251                         verdict = t->u.target->target(skb, &acpar);
252                 }
253                 if (verdict == EBT_ACCEPT) {
254                         read_unlock_bh(&table->lock);
255                         return NF_ACCEPT;
256                 }
257                 if (verdict == EBT_DROP) {
258                         read_unlock_bh(&table->lock);
259                         return NF_DROP;
260                 }
261                 if (verdict == EBT_RETURN) {
262 letsreturn:
263                         if (WARN(sp == 0, "RETURN on base chain")) {
264                                 /* act like this is EBT_CONTINUE */
265                                 goto letscontinue;
266                         }
267
268                         sp--;
269                         /* put all the local variables right */
270                         i = cs[sp].n;
271                         chaininfo = cs[sp].chaininfo;
272                         nentries = chaininfo->nentries;
273                         point = cs[sp].e;
274                         counter_base = cb_base +
275                            chaininfo->counter_offset;
276                         continue;
277                 }
278                 if (verdict == EBT_CONTINUE)
279                         goto letscontinue;
280
281                 if (WARN(verdict < 0, "bogus standard verdict\n")) {
282                         read_unlock_bh(&table->lock);
283                         return NF_DROP;
284                 }
285
286                 /* jump to a udc */
287                 cs[sp].n = i + 1;
288                 cs[sp].chaininfo = chaininfo;
289                 cs[sp].e = ebt_next_entry(point);
290                 i = 0;
291                 chaininfo = (struct ebt_entries *) (base + verdict);
292
293                 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
294                         read_unlock_bh(&table->lock);
295                         return NF_DROP;
296                 }
297
298                 nentries = chaininfo->nentries;
299                 point = (struct ebt_entry *)chaininfo->data;
300                 counter_base = cb_base + chaininfo->counter_offset;
301                 sp++;
302                 continue;
303 letscontinue:
304                 point = ebt_next_entry(point);
305                 i++;
306         }
307
308         /* I actually like this :) */
309         if (chaininfo->policy == EBT_RETURN)
310                 goto letsreturn;
311         if (chaininfo->policy == EBT_ACCEPT) {
312                 read_unlock_bh(&table->lock);
313                 return NF_ACCEPT;
314         }
315         read_unlock_bh(&table->lock);
316         return NF_DROP;
317 }
318
319 /* If it succeeds, returns element and locks mutex */
320 static inline void *
321 find_inlist_lock_noload(struct net *net, const char *name, int *error,
322                         struct mutex *mutex)
323 {
324         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
325         struct ebt_template *tmpl;
326         struct ebt_table *table;
327
328         mutex_lock(mutex);
329         list_for_each_entry(table, &ebt_net->tables, list) {
330                 if (strcmp(table->name, name) == 0)
331                         return table;
332         }
333
334         list_for_each_entry(tmpl, &template_tables, list) {
335                 if (strcmp(name, tmpl->name) == 0) {
336                         struct module *owner = tmpl->owner;
337
338                         if (!try_module_get(owner))
339                                 goto out;
340
341                         mutex_unlock(mutex);
342
343                         *error = tmpl->table_init(net);
344                         if (*error) {
345                                 module_put(owner);
346                                 return NULL;
347                         }
348
349                         mutex_lock(mutex);
350                         module_put(owner);
351                         break;
352                 }
353         }
354
355         list_for_each_entry(table, &ebt_net->tables, list) {
356                 if (strcmp(table->name, name) == 0)
357                         return table;
358         }
359
360 out:
361         *error = -ENOENT;
362         mutex_unlock(mutex);
363         return NULL;
364 }
365
366 static void *
367 find_inlist_lock(struct net *net, const char *name, const char *prefix,
368                  int *error, struct mutex *mutex)
369 {
370         return try_then_request_module(
371                         find_inlist_lock_noload(net, name, error, mutex),
372                         "%s%s", prefix, name);
373 }
374
375 static inline struct ebt_table *
376 find_table_lock(struct net *net, const char *name, int *error,
377                 struct mutex *mutex)
378 {
379         return find_inlist_lock(net, name, "ebtable_", error, mutex);
380 }
381
382 static inline void ebt_free_table_info(struct ebt_table_info *info)
383 {
384         int i;
385
386         if (info->chainstack) {
387                 for_each_possible_cpu(i)
388                         vfree(info->chainstack[i]);
389                 vfree(info->chainstack);
390         }
391 }
392 static inline int
393 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
394                 unsigned int *cnt)
395 {
396         const struct ebt_entry *e = par->entryinfo;
397         struct xt_match *match;
398         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
399         int ret;
400
401         if (left < sizeof(struct ebt_entry_match) ||
402             left - sizeof(struct ebt_entry_match) < m->match_size)
403                 return -EINVAL;
404
405         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
406         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
407                 if (!IS_ERR(match))
408                         module_put(match->me);
409                 request_module("ebt_%s", m->u.name);
410                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
411         }
412         if (IS_ERR(match))
413                 return PTR_ERR(match);
414         m->u.match = match;
415
416         par->match     = match;
417         par->matchinfo = m->data;
418         ret = xt_check_match(par, m->match_size,
419               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
420         if (ret < 0) {
421                 module_put(match->me);
422                 return ret;
423         }
424
425         (*cnt)++;
426         return 0;
427 }
428
429 static inline int
430 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
431                   unsigned int *cnt)
432 {
433         const struct ebt_entry *e = par->entryinfo;
434         struct xt_target *watcher;
435         size_t left = ((char *)e + e->target_offset) - (char *)w;
436         int ret;
437
438         if (left < sizeof(struct ebt_entry_watcher) ||
439            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
440                 return -EINVAL;
441
442         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
443         if (IS_ERR(watcher))
444                 return PTR_ERR(watcher);
445
446         if (watcher->family != NFPROTO_BRIDGE) {
447                 module_put(watcher->me);
448                 return -ENOENT;
449         }
450
451         w->u.watcher = watcher;
452
453         par->target   = watcher;
454         par->targinfo = w->data;
455         ret = xt_check_target(par, w->watcher_size,
456               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
457         if (ret < 0) {
458                 module_put(watcher->me);
459                 return ret;
460         }
461
462         (*cnt)++;
463         return 0;
464 }
465
466 static int ebt_verify_pointers(const struct ebt_replace *repl,
467                                struct ebt_table_info *newinfo)
468 {
469         unsigned int limit = repl->entries_size;
470         unsigned int valid_hooks = repl->valid_hooks;
471         unsigned int offset = 0;
472         int i;
473
474         for (i = 0; i < NF_BR_NUMHOOKS; i++)
475                 newinfo->hook_entry[i] = NULL;
476
477         newinfo->entries_size = repl->entries_size;
478         newinfo->nentries = repl->nentries;
479
480         while (offset < limit) {
481                 size_t left = limit - offset;
482                 struct ebt_entry *e = (void *)newinfo->entries + offset;
483
484                 if (left < sizeof(unsigned int))
485                         break;
486
487                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
488                         if ((valid_hooks & (1 << i)) == 0)
489                                 continue;
490                         if ((char __user *)repl->hook_entry[i] ==
491                              repl->entries + offset)
492                                 break;
493                 }
494
495                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
496                         if (e->bitmask != 0) {
497                                 /* we make userspace set this right,
498                                  * so there is no misunderstanding
499                                  */
500                                 return -EINVAL;
501                         }
502                         if (i != NF_BR_NUMHOOKS)
503                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
504                         if (left < sizeof(struct ebt_entries))
505                                 break;
506                         offset += sizeof(struct ebt_entries);
507                 } else {
508                         if (left < sizeof(struct ebt_entry))
509                                 break;
510                         if (left < e->next_offset)
511                                 break;
512                         if (e->next_offset < sizeof(struct ebt_entry))
513                                 return -EINVAL;
514                         offset += e->next_offset;
515                 }
516         }
517         if (offset != limit)
518                 return -EINVAL;
519
520         /* check if all valid hooks have a chain */
521         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
522                 if (!newinfo->hook_entry[i] &&
523                    (valid_hooks & (1 << i)))
524                         return -EINVAL;
525         }
526         return 0;
527 }
528
529 /* this one is very careful, as it is the first function
530  * to parse the userspace data
531  */
532 static inline int
533 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
534                                const struct ebt_table_info *newinfo,
535                                unsigned int *n, unsigned int *cnt,
536                                unsigned int *totalcnt, unsigned int *udc_cnt)
537 {
538         int i;
539
540         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
541                 if ((void *)e == (void *)newinfo->hook_entry[i])
542                         break;
543         }
544         /* beginning of a new chain
545          * if i == NF_BR_NUMHOOKS it must be a user defined chain
546          */
547         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
548                 /* this checks if the previous chain has as many entries
549                  * as it said it has
550                  */
551                 if (*n != *cnt)
552                         return -EINVAL;
553
554                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
555                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
556                         /* only RETURN from udc */
557                         if (i != NF_BR_NUMHOOKS ||
558                            ((struct ebt_entries *)e)->policy != EBT_RETURN)
559                                 return -EINVAL;
560                 }
561                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
562                         (*udc_cnt)++;
563                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
564                         return -EINVAL;
565                 *n = ((struct ebt_entries *)e)->nentries;
566                 *cnt = 0;
567                 return 0;
568         }
569         /* a plain old entry, heh */
570         if (sizeof(struct ebt_entry) > e->watchers_offset ||
571            e->watchers_offset > e->target_offset ||
572            e->target_offset >= e->next_offset)
573                 return -EINVAL;
574
575         /* this is not checked anywhere else */
576         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
577                 return -EINVAL;
578
579         (*cnt)++;
580         (*totalcnt)++;
581         return 0;
582 }
583
584 struct ebt_cl_stack {
585         struct ebt_chainstack cs;
586         int from;
587         unsigned int hookmask;
588 };
589
590 /* We need these positions to check that the jumps to a different part of the
591  * entries is a jump to the beginning of a new chain.
592  */
593 static inline int
594 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
595                       unsigned int *n, struct ebt_cl_stack *udc)
596 {
597         int i;
598
599         /* we're only interested in chain starts */
600         if (e->bitmask)
601                 return 0;
602         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
603                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
604                         break;
605         }
606         /* only care about udc */
607         if (i != NF_BR_NUMHOOKS)
608                 return 0;
609
610         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
611         /* these initialisations are depended on later in check_chainloops() */
612         udc[*n].cs.n = 0;
613         udc[*n].hookmask = 0;
614
615         (*n)++;
616         return 0;
617 }
618
619 static inline int
620 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
621 {
622         struct xt_mtdtor_param par;
623
624         if (i && (*i)-- == 0)
625                 return 1;
626
627         par.net       = net;
628         par.match     = m->u.match;
629         par.matchinfo = m->data;
630         par.family    = NFPROTO_BRIDGE;
631         if (par.match->destroy != NULL)
632                 par.match->destroy(&par);
633         module_put(par.match->me);
634         return 0;
635 }
636
637 static inline int
638 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
639 {
640         struct xt_tgdtor_param par;
641
642         if (i && (*i)-- == 0)
643                 return 1;
644
645         par.net      = net;
646         par.target   = w->u.watcher;
647         par.targinfo = w->data;
648         par.family   = NFPROTO_BRIDGE;
649         if (par.target->destroy != NULL)
650                 par.target->destroy(&par);
651         module_put(par.target->me);
652         return 0;
653 }
654
655 static inline int
656 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
657 {
658         struct xt_tgdtor_param par;
659         struct ebt_entry_target *t;
660
661         if (e->bitmask == 0)
662                 return 0;
663         /* we're done */
664         if (cnt && (*cnt)-- == 0)
665                 return 1;
666         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
667         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
668         t = ebt_get_target(e);
669
670         par.net      = net;
671         par.target   = t->u.target;
672         par.targinfo = t->data;
673         par.family   = NFPROTO_BRIDGE;
674         if (par.target->destroy != NULL)
675                 par.target->destroy(&par);
676         module_put(par.target->me);
677         return 0;
678 }
679
680 static inline int
681 ebt_check_entry(struct ebt_entry *e, struct net *net,
682                 const struct ebt_table_info *newinfo,
683                 const char *name, unsigned int *cnt,
684                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
685 {
686         struct ebt_entry_target *t;
687         struct xt_target *target;
688         unsigned int i, j, hook = 0, hookmask = 0;
689         size_t gap;
690         int ret;
691         struct xt_mtchk_param mtpar;
692         struct xt_tgchk_param tgpar;
693
694         /* don't mess with the struct ebt_entries */
695         if (e->bitmask == 0)
696                 return 0;
697
698         if (e->bitmask & ~EBT_F_MASK)
699                 return -EINVAL;
700
701         if (e->invflags & ~EBT_INV_MASK)
702                 return -EINVAL;
703
704         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
705                 return -EINVAL;
706
707         /* what hook do we belong to? */
708         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
709                 if (!newinfo->hook_entry[i])
710                         continue;
711                 if ((char *)newinfo->hook_entry[i] < (char *)e)
712                         hook = i;
713                 else
714                         break;
715         }
716         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
717          * a base chain
718          */
719         if (i < NF_BR_NUMHOOKS)
720                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
721         else {
722                 for (i = 0; i < udc_cnt; i++)
723                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
724                                 break;
725                 if (i == 0)
726                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
727                 else
728                         hookmask = cl_s[i - 1].hookmask;
729         }
730         i = 0;
731
732         memset(&mtpar, 0, sizeof(mtpar));
733         memset(&tgpar, 0, sizeof(tgpar));
734         mtpar.net       = tgpar.net       = net;
735         mtpar.table     = tgpar.table     = name;
736         mtpar.entryinfo = tgpar.entryinfo = e;
737         mtpar.hook_mask = tgpar.hook_mask = hookmask;
738         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
739         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
740         if (ret != 0)
741                 goto cleanup_matches;
742         j = 0;
743         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
744         if (ret != 0)
745                 goto cleanup_watchers;
746         t = ebt_get_target(e);
747         gap = e->next_offset - e->target_offset;
748
749         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
750         if (IS_ERR(target)) {
751                 ret = PTR_ERR(target);
752                 goto cleanup_watchers;
753         }
754
755         /* Reject UNSPEC, xtables verdicts/return values are incompatible */
756         if (target->family != NFPROTO_BRIDGE) {
757                 module_put(target->me);
758                 ret = -ENOENT;
759                 goto cleanup_watchers;
760         }
761
762         t->u.target = target;
763         if (t->u.target == &ebt_standard_target) {
764                 if (gap < sizeof(struct ebt_standard_target)) {
765                         ret = -EFAULT;
766                         goto cleanup_watchers;
767                 }
768                 if (((struct ebt_standard_target *)t)->verdict <
769                    -NUM_STANDARD_TARGETS) {
770                         ret = -EFAULT;
771                         goto cleanup_watchers;
772                 }
773         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
774                 module_put(t->u.target->me);
775                 ret = -EFAULT;
776                 goto cleanup_watchers;
777         }
778
779         tgpar.target   = target;
780         tgpar.targinfo = t->data;
781         ret = xt_check_target(&tgpar, t->target_size,
782               ntohs(e->ethproto), e->invflags & EBT_IPROTO);
783         if (ret < 0) {
784                 module_put(target->me);
785                 goto cleanup_watchers;
786         }
787         (*cnt)++;
788         return 0;
789 cleanup_watchers:
790         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
791 cleanup_matches:
792         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
793         return ret;
794 }
795
796 /* checks for loops and sets the hook mask for udc
797  * the hook mask for udc tells us from which base chains the udc can be
798  * accessed. This mask is a parameter to the check() functions of the extensions
799  */
800 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
801                             unsigned int udc_cnt, unsigned int hooknr, char *base)
802 {
803         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
804         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
805         const struct ebt_entry_target *t;
806
807         while (pos < nentries || chain_nr != -1) {
808                 /* end of udc, go back one 'recursion' step */
809                 if (pos == nentries) {
810                         /* put back values of the time when this chain was called */
811                         e = cl_s[chain_nr].cs.e;
812                         if (cl_s[chain_nr].from != -1)
813                                 nentries =
814                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
815                         else
816                                 nentries = chain->nentries;
817                         pos = cl_s[chain_nr].cs.n;
818                         /* make sure we won't see a loop that isn't one */
819                         cl_s[chain_nr].cs.n = 0;
820                         chain_nr = cl_s[chain_nr].from;
821                         if (pos == nentries)
822                                 continue;
823                 }
824                 t = ebt_get_target_c(e);
825                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
826                         goto letscontinue;
827                 if (e->target_offset + sizeof(struct ebt_standard_target) >
828                    e->next_offset)
829                         return -1;
830
831                 verdict = ((struct ebt_standard_target *)t)->verdict;
832                 if (verdict >= 0) { /* jump to another chain */
833                         struct ebt_entries *hlp2 =
834                            (struct ebt_entries *)(base + verdict);
835                         for (i = 0; i < udc_cnt; i++)
836                                 if (hlp2 == cl_s[i].cs.chaininfo)
837                                         break;
838                         /* bad destination or loop */
839                         if (i == udc_cnt)
840                                 return -1;
841
842                         if (cl_s[i].cs.n)
843                                 return -1;
844
845                         if (cl_s[i].hookmask & (1 << hooknr))
846                                 goto letscontinue;
847                         /* this can't be 0, so the loop test is correct */
848                         cl_s[i].cs.n = pos + 1;
849                         pos = 0;
850                         cl_s[i].cs.e = ebt_next_entry(e);
851                         e = (struct ebt_entry *)(hlp2->data);
852                         nentries = hlp2->nentries;
853                         cl_s[i].from = chain_nr;
854                         chain_nr = i;
855                         /* this udc is accessible from the base chain for hooknr */
856                         cl_s[i].hookmask |= (1 << hooknr);
857                         continue;
858                 }
859 letscontinue:
860                 e = ebt_next_entry(e);
861                 pos++;
862         }
863         return 0;
864 }
865
866 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
867 static int translate_table(struct net *net, const char *name,
868                            struct ebt_table_info *newinfo)
869 {
870         unsigned int i, j, k, udc_cnt;
871         int ret;
872         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
873
874         i = 0;
875         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
876                 i++;
877         if (i == NF_BR_NUMHOOKS)
878                 return -EINVAL;
879
880         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
881                 return -EINVAL;
882
883         /* make sure chains are ordered after each other in same order
884          * as their corresponding hooks
885          */
886         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
887                 if (!newinfo->hook_entry[j])
888                         continue;
889                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
890                         return -EINVAL;
891
892                 i = j;
893         }
894
895         /* do some early checkings and initialize some things */
896         i = 0; /* holds the expected nr. of entries for the chain */
897         j = 0; /* holds the up to now counted entries for the chain */
898         k = 0; /* holds the total nr. of entries, should equal
899                 * newinfo->nentries afterwards
900                 */
901         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
902         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
903            ebt_check_entry_size_and_hooks, newinfo,
904            &i, &j, &k, &udc_cnt);
905
906         if (ret != 0)
907                 return ret;
908
909         if (i != j)
910                 return -EINVAL;
911
912         if (k != newinfo->nentries)
913                 return -EINVAL;
914
915         /* get the location of the udc, put them in an array
916          * while we're at it, allocate the chainstack
917          */
918         if (udc_cnt) {
919                 /* this will get free'd in do_replace()/ebt_register_table()
920                  * if an error occurs
921                  */
922                 newinfo->chainstack =
923                         vmalloc(array_size(nr_cpu_ids,
924                                            sizeof(*(newinfo->chainstack))));
925                 if (!newinfo->chainstack)
926                         return -ENOMEM;
927                 for_each_possible_cpu(i) {
928                         newinfo->chainstack[i] =
929                           vmalloc_node(array_size(udc_cnt,
930                                           sizeof(*(newinfo->chainstack[0]))),
931                                        cpu_to_node(i));
932                         if (!newinfo->chainstack[i]) {
933                                 while (i)
934                                         vfree(newinfo->chainstack[--i]);
935                                 vfree(newinfo->chainstack);
936                                 newinfo->chainstack = NULL;
937                                 return -ENOMEM;
938                         }
939                 }
940
941                 cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
942                 if (!cl_s)
943                         return -ENOMEM;
944                 i = 0; /* the i'th udc */
945                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
946                    ebt_get_udc_positions, newinfo, &i, cl_s);
947                 /* sanity check */
948                 if (i != udc_cnt) {
949                         vfree(cl_s);
950                         return -EFAULT;
951                 }
952         }
953
954         /* Check for loops */
955         for (i = 0; i < NF_BR_NUMHOOKS; i++)
956                 if (newinfo->hook_entry[i])
957                         if (check_chainloops(newinfo->hook_entry[i],
958                            cl_s, udc_cnt, i, newinfo->entries)) {
959                                 vfree(cl_s);
960                                 return -EINVAL;
961                         }
962
963         /* we now know the following (along with E=mc²):
964          *  - the nr of entries in each chain is right
965          *  - the size of the allocated space is right
966          *  - all valid hooks have a corresponding chain
967          *  - there are no loops
968          *  - wrong data can still be on the level of a single entry
969          *  - could be there are jumps to places that are not the
970          *    beginning of a chain. This can only occur in chains that
971          *    are not accessible from any base chains, so we don't care.
972          */
973
974         /* used to know what we need to clean up if something goes wrong */
975         i = 0;
976         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
977            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
978         if (ret != 0) {
979                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
980                                   ebt_cleanup_entry, net, &i);
981         }
982         vfree(cl_s);
983         return ret;
984 }
985
986 /* called under write_lock */
987 static void get_counters(const struct ebt_counter *oldcounters,
988                          struct ebt_counter *counters, unsigned int nentries)
989 {
990         int i, cpu;
991         struct ebt_counter *counter_base;
992
993         /* counters of cpu 0 */
994         memcpy(counters, oldcounters,
995                sizeof(struct ebt_counter) * nentries);
996
997         /* add other counters to those of cpu 0 */
998         for_each_possible_cpu(cpu) {
999                 if (cpu == 0)
1000                         continue;
1001                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
1002                 for (i = 0; i < nentries; i++)
1003                         ADD_COUNTER(counters[i], counter_base[i].bcnt,
1004                                     counter_base[i].pcnt);
1005         }
1006 }
1007
1008 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1009                               struct ebt_table_info *newinfo)
1010 {
1011         int ret;
1012         struct ebt_counter *counterstmp = NULL;
1013         /* used to be able to unlock earlier */
1014         struct ebt_table_info *table;
1015         struct ebt_table *t;
1016
1017         /* the user wants counters back
1018          * the check on the size is done later, when we have the lock
1019          */
1020         if (repl->num_counters) {
1021                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1022                 counterstmp = vmalloc(size);
1023                 if (!counterstmp)
1024                         return -ENOMEM;
1025         }
1026
1027         newinfo->chainstack = NULL;
1028         ret = ebt_verify_pointers(repl, newinfo);
1029         if (ret != 0)
1030                 goto free_counterstmp;
1031
1032         ret = translate_table(net, repl->name, newinfo);
1033
1034         if (ret != 0)
1035                 goto free_counterstmp;
1036
1037         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1038         if (!t) {
1039                 ret = -ENOENT;
1040                 goto free_iterate;
1041         }
1042
1043         if (repl->valid_hooks != t->valid_hooks) {
1044                 ret = -EINVAL;
1045                 goto free_unlock;
1046         }
1047
1048         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1049                 ret = -EINVAL;
1050                 goto free_unlock;
1051         }
1052
1053         /* we have the mutex lock, so no danger in reading this pointer */
1054         table = t->private;
1055         /* make sure the table can only be rmmod'ed if it contains no rules */
1056         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1057                 ret = -ENOENT;
1058                 goto free_unlock;
1059         } else if (table->nentries && !newinfo->nentries)
1060                 module_put(t->me);
1061         /* we need an atomic snapshot of the counters */
1062         write_lock_bh(&t->lock);
1063         if (repl->num_counters)
1064                 get_counters(t->private->counters, counterstmp,
1065                    t->private->nentries);
1066
1067         t->private = newinfo;
1068         write_unlock_bh(&t->lock);
1069         mutex_unlock(&ebt_mutex);
1070         /* so, a user can change the chains while having messed up her counter
1071          * allocation. Only reason why this is done is because this way the lock
1072          * is held only once, while this doesn't bring the kernel into a
1073          * dangerous state.
1074          */
1075         if (repl->num_counters &&
1076            copy_to_user(repl->counters, counterstmp,
1077            array_size(repl->num_counters, sizeof(struct ebt_counter)))) {
1078                 /* Silent error, can't fail, new table is already in place */
1079                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1080         }
1081
1082         /* decrease module count and free resources */
1083         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1084                           ebt_cleanup_entry, net, NULL);
1085
1086         vfree(table->entries);
1087         ebt_free_table_info(table);
1088         vfree(table);
1089         vfree(counterstmp);
1090
1091         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1092                         AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1093         return 0;
1094
1095 free_unlock:
1096         mutex_unlock(&ebt_mutex);
1097 free_iterate:
1098         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1099                           ebt_cleanup_entry, net, NULL);
1100 free_counterstmp:
1101         vfree(counterstmp);
1102         /* can be initialized in translate_table() */
1103         ebt_free_table_info(newinfo);
1104         return ret;
1105 }
1106
1107 /* replace the table */
1108 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1109 {
1110         int ret, countersize;
1111         struct ebt_table_info *newinfo;
1112         struct ebt_replace tmp;
1113
1114         if (len < sizeof(tmp))
1115                 return -EINVAL;
1116         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1117                 return -EFAULT;
1118
1119         if (len != sizeof(tmp) + tmp.entries_size)
1120                 return -EINVAL;
1121
1122         if (tmp.entries_size == 0)
1123                 return -EINVAL;
1124
1125         /* overflow check */
1126         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1127                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1128                 return -ENOMEM;
1129         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1130                 return -ENOMEM;
1131
1132         tmp.name[sizeof(tmp.name) - 1] = 0;
1133
1134         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1135         newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1136         if (!newinfo)
1137                 return -ENOMEM;
1138
1139         if (countersize)
1140                 memset(newinfo->counters, 0, countersize);
1141
1142         newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1143         if (!newinfo->entries) {
1144                 ret = -ENOMEM;
1145                 goto free_newinfo;
1146         }
1147         if (copy_from_user(
1148            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1149                 ret = -EFAULT;
1150                 goto free_entries;
1151         }
1152
1153         ret = do_replace_finish(net, &tmp, newinfo);
1154         if (ret == 0)
1155                 return ret;
1156 free_entries:
1157         vfree(newinfo->entries);
1158 free_newinfo:
1159         vfree(newinfo);
1160         return ret;
1161 }
1162
1163 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1164 {
1165         mutex_lock(&ebt_mutex);
1166         list_del(&table->list);
1167         mutex_unlock(&ebt_mutex);
1168         audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1169                         AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1170         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1171                           ebt_cleanup_entry, net, NULL);
1172         if (table->private->nentries)
1173                 module_put(table->me);
1174         vfree(table->private->entries);
1175         ebt_free_table_info(table->private);
1176         vfree(table->private);
1177         kfree(table->ops);
1178         kfree(table);
1179 }
1180
1181 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1182                        const struct nf_hook_ops *template_ops)
1183 {
1184         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1185         struct ebt_table_info *newinfo;
1186         struct ebt_table *t, *table;
1187         struct nf_hook_ops *ops;
1188         unsigned int num_ops;
1189         struct ebt_replace_kernel *repl;
1190         int ret, i, countersize;
1191         void *p;
1192
1193         if (input_table == NULL || (repl = input_table->table) == NULL ||
1194             repl->entries == NULL || repl->entries_size == 0 ||
1195             repl->counters != NULL || input_table->private != NULL)
1196                 return -EINVAL;
1197
1198         /* Don't add one table to multiple lists. */
1199         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1200         if (!table) {
1201                 ret = -ENOMEM;
1202                 goto out;
1203         }
1204
1205         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1206         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1207         ret = -ENOMEM;
1208         if (!newinfo)
1209                 goto free_table;
1210
1211         p = vmalloc(repl->entries_size);
1212         if (!p)
1213                 goto free_newinfo;
1214
1215         memcpy(p, repl->entries, repl->entries_size);
1216         newinfo->entries = p;
1217
1218         newinfo->entries_size = repl->entries_size;
1219         newinfo->nentries = repl->nentries;
1220
1221         if (countersize)
1222                 memset(newinfo->counters, 0, countersize);
1223
1224         /* fill in newinfo and parse the entries */
1225         newinfo->chainstack = NULL;
1226         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1227                 if ((repl->valid_hooks & (1 << i)) == 0)
1228                         newinfo->hook_entry[i] = NULL;
1229                 else
1230                         newinfo->hook_entry[i] = p +
1231                                 ((char *)repl->hook_entry[i] - repl->entries);
1232         }
1233         ret = translate_table(net, repl->name, newinfo);
1234         if (ret != 0)
1235                 goto free_chainstack;
1236
1237         table->private = newinfo;
1238         rwlock_init(&table->lock);
1239         mutex_lock(&ebt_mutex);
1240         list_for_each_entry(t, &ebt_net->tables, list) {
1241                 if (strcmp(t->name, table->name) == 0) {
1242                         ret = -EEXIST;
1243                         goto free_unlock;
1244                 }
1245         }
1246
1247         /* Hold a reference count if the chains aren't empty */
1248         if (newinfo->nentries && !try_module_get(table->me)) {
1249                 ret = -ENOENT;
1250                 goto free_unlock;
1251         }
1252
1253         num_ops = hweight32(table->valid_hooks);
1254         if (num_ops == 0) {
1255                 ret = -EINVAL;
1256                 goto free_unlock;
1257         }
1258
1259         ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1260         if (!ops) {
1261                 ret = -ENOMEM;
1262                 if (newinfo->nentries)
1263                         module_put(table->me);
1264                 goto free_unlock;
1265         }
1266
1267         for (i = 0; i < num_ops; i++)
1268                 ops[i].priv = table;
1269
1270         list_add(&table->list, &ebt_net->tables);
1271         mutex_unlock(&ebt_mutex);
1272
1273         table->ops = ops;
1274         ret = nf_register_net_hooks(net, ops, num_ops);
1275         if (ret)
1276                 __ebt_unregister_table(net, table);
1277
1278         audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1279                         AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1280         return ret;
1281 free_unlock:
1282         mutex_unlock(&ebt_mutex);
1283 free_chainstack:
1284         ebt_free_table_info(newinfo);
1285         vfree(newinfo->entries);
1286 free_newinfo:
1287         vfree(newinfo);
1288 free_table:
1289         kfree(table);
1290 out:
1291         return ret;
1292 }
1293
1294 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1295 {
1296         struct ebt_template *tmpl;
1297
1298         mutex_lock(&ebt_mutex);
1299         list_for_each_entry(tmpl, &template_tables, list) {
1300                 if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1301                         mutex_unlock(&ebt_mutex);
1302                         return -EEXIST;
1303                 }
1304         }
1305
1306         tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1307         if (!tmpl) {
1308                 mutex_unlock(&ebt_mutex);
1309                 return -ENOMEM;
1310         }
1311
1312         tmpl->table_init = table_init;
1313         strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1314         tmpl->owner = t->me;
1315         list_add(&tmpl->list, &template_tables);
1316
1317         mutex_unlock(&ebt_mutex);
1318         return 0;
1319 }
1320 EXPORT_SYMBOL(ebt_register_template);
1321
1322 void ebt_unregister_template(const struct ebt_table *t)
1323 {
1324         struct ebt_template *tmpl;
1325
1326         mutex_lock(&ebt_mutex);
1327         list_for_each_entry(tmpl, &template_tables, list) {
1328                 if (strcmp(t->name, tmpl->name))
1329                         continue;
1330
1331                 list_del(&tmpl->list);
1332                 mutex_unlock(&ebt_mutex);
1333                 kfree(tmpl);
1334                 return;
1335         }
1336
1337         mutex_unlock(&ebt_mutex);
1338         WARN_ON_ONCE(1);
1339 }
1340 EXPORT_SYMBOL(ebt_unregister_template);
1341
1342 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1343 {
1344         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1345         struct ebt_table *t;
1346
1347         mutex_lock(&ebt_mutex);
1348
1349         list_for_each_entry(t, &ebt_net->tables, list) {
1350                 if (strcmp(t->name, name) == 0) {
1351                         mutex_unlock(&ebt_mutex);
1352                         return t;
1353                 }
1354         }
1355
1356         mutex_unlock(&ebt_mutex);
1357         return NULL;
1358 }
1359
1360 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1361 {
1362         struct ebt_table *table = __ebt_find_table(net, name);
1363
1364         if (table)
1365                 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1366 }
1367 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1368
1369 void ebt_unregister_table(struct net *net, const char *name)
1370 {
1371         struct ebt_table *table = __ebt_find_table(net, name);
1372
1373         if (table)
1374                 __ebt_unregister_table(net, table);
1375 }
1376
1377 /* userspace just supplied us with counters */
1378 static int do_update_counters(struct net *net, const char *name,
1379                               struct ebt_counter __user *counters,
1380                               unsigned int num_counters, unsigned int len)
1381 {
1382         int i, ret;
1383         struct ebt_counter *tmp;
1384         struct ebt_table *t;
1385
1386         if (num_counters == 0)
1387                 return -EINVAL;
1388
1389         tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1390         if (!tmp)
1391                 return -ENOMEM;
1392
1393         t = find_table_lock(net, name, &ret, &ebt_mutex);
1394         if (!t)
1395                 goto free_tmp;
1396
1397         if (num_counters != t->private->nentries) {
1398                 ret = -EINVAL;
1399                 goto unlock_mutex;
1400         }
1401
1402         if (copy_from_user(tmp, counters,
1403                            array_size(num_counters, sizeof(*counters)))) {
1404                 ret = -EFAULT;
1405                 goto unlock_mutex;
1406         }
1407
1408         /* we want an atomic add of the counters */
1409         write_lock_bh(&t->lock);
1410
1411         /* we add to the counters of the first cpu */
1412         for (i = 0; i < num_counters; i++)
1413                 ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1414
1415         write_unlock_bh(&t->lock);
1416         ret = 0;
1417 unlock_mutex:
1418         mutex_unlock(&ebt_mutex);
1419 free_tmp:
1420         vfree(tmp);
1421         return ret;
1422 }
1423
1424 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1425 {
1426         struct ebt_replace hlp;
1427
1428         if (len < sizeof(hlp))
1429                 return -EINVAL;
1430         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1431                 return -EFAULT;
1432
1433         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1434                 return -EINVAL;
1435
1436         return do_update_counters(net, hlp.name, hlp.counters,
1437                                   hlp.num_counters, len);
1438 }
1439
1440 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1441                                   const char *data, int entrysize,
1442                                   int usersize, int datasize, u8 revision)
1443 {
1444         char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1445
1446         /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1447          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1448          */
1449         strscpy(name, _name, sizeof(name));
1450         if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1451             put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1452             put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1453             xt_data_to_user(um + entrysize, data, usersize, datasize,
1454                             XT_ALIGN(datasize)))
1455                 return -EFAULT;
1456
1457         return 0;
1458 }
1459
1460 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1461                                     const char *base, char __user *ubase)
1462 {
1463         return ebt_obj_to_user(ubase + ((char *)m - base),
1464                                m->u.match->name, m->data, sizeof(*m),
1465                                m->u.match->usersize, m->match_size,
1466                                m->u.match->revision);
1467 }
1468
1469 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1470                                       const char *base, char __user *ubase)
1471 {
1472         return ebt_obj_to_user(ubase + ((char *)w - base),
1473                                w->u.watcher->name, w->data, sizeof(*w),
1474                                w->u.watcher->usersize, w->watcher_size,
1475                                w->u.watcher->revision);
1476 }
1477
1478 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1479                                     char __user *ubase)
1480 {
1481         int ret;
1482         char __user *hlp;
1483         const struct ebt_entry_target *t;
1484
1485         if (e->bitmask == 0) {
1486                 /* special case !EBT_ENTRY_OR_ENTRIES */
1487                 if (copy_to_user(ubase + ((char *)e - base), e,
1488                                  sizeof(struct ebt_entries)))
1489                         return -EFAULT;
1490                 return 0;
1491         }
1492
1493         if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1494                 return -EFAULT;
1495
1496         hlp = ubase + (((char *)e + e->target_offset) - base);
1497         t = ebt_get_target_c(e);
1498
1499         ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1500         if (ret != 0)
1501                 return ret;
1502         ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1503         if (ret != 0)
1504                 return ret;
1505         ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1506                               t->u.target->usersize, t->target_size,
1507                               t->u.target->revision);
1508         if (ret != 0)
1509                 return ret;
1510
1511         return 0;
1512 }
1513
1514 static int copy_counters_to_user(struct ebt_table *t,
1515                                  const struct ebt_counter *oldcounters,
1516                                  void __user *user, unsigned int num_counters,
1517                                  unsigned int nentries)
1518 {
1519         struct ebt_counter *counterstmp;
1520         int ret = 0;
1521
1522         /* userspace might not need the counters */
1523         if (num_counters == 0)
1524                 return 0;
1525
1526         if (num_counters != nentries)
1527                 return -EINVAL;
1528
1529         counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1530         if (!counterstmp)
1531                 return -ENOMEM;
1532
1533         write_lock_bh(&t->lock);
1534         get_counters(oldcounters, counterstmp, nentries);
1535         write_unlock_bh(&t->lock);
1536
1537         if (copy_to_user(user, counterstmp,
1538             array_size(nentries, sizeof(struct ebt_counter))))
1539                 ret = -EFAULT;
1540         vfree(counterstmp);
1541         return ret;
1542 }
1543
1544 /* called with ebt_mutex locked */
1545 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1546                                    const int *len, int cmd)
1547 {
1548         struct ebt_replace tmp;
1549         const struct ebt_counter *oldcounters;
1550         unsigned int entries_size, nentries;
1551         int ret;
1552         char *entries;
1553
1554         if (cmd == EBT_SO_GET_ENTRIES) {
1555                 entries_size = t->private->entries_size;
1556                 nentries = t->private->nentries;
1557                 entries = t->private->entries;
1558                 oldcounters = t->private->counters;
1559         } else {
1560                 entries_size = t->table->entries_size;
1561                 nentries = t->table->nentries;
1562                 entries = t->table->entries;
1563                 oldcounters = t->table->counters;
1564         }
1565
1566         if (copy_from_user(&tmp, user, sizeof(tmp)))
1567                 return -EFAULT;
1568
1569         if (*len != sizeof(struct ebt_replace) + entries_size +
1570            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1571                 return -EINVAL;
1572
1573         if (tmp.nentries != nentries)
1574                 return -EINVAL;
1575
1576         if (tmp.entries_size != entries_size)
1577                 return -EINVAL;
1578
1579         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1580                                         tmp.num_counters, nentries);
1581         if (ret)
1582                 return ret;
1583
1584         /* set the match/watcher/target names right */
1585         return EBT_ENTRY_ITERATE(entries, entries_size,
1586            ebt_entry_to_user, entries, tmp.entries);
1587 }
1588
1589 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1590 /* 32 bit-userspace compatibility definitions. */
1591 struct compat_ebt_replace {
1592         char name[EBT_TABLE_MAXNAMELEN];
1593         compat_uint_t valid_hooks;
1594         compat_uint_t nentries;
1595         compat_uint_t entries_size;
1596         /* start of the chains */
1597         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1598         /* nr of counters userspace expects back */
1599         compat_uint_t num_counters;
1600         /* where the kernel will put the old counters. */
1601         compat_uptr_t counters;
1602         compat_uptr_t entries;
1603 };
1604
1605 /* struct ebt_entry_match, _target and _watcher have same layout */
1606 struct compat_ebt_entry_mwt {
1607         union {
1608                 struct {
1609                         char name[EBT_EXTENSION_MAXNAMELEN];
1610                         u8 revision;
1611                 };
1612                 compat_uptr_t ptr;
1613         } u;
1614         compat_uint_t match_size;
1615         compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1616 };
1617
1618 /* account for possible padding between match_size and ->data */
1619 static int ebt_compat_entry_padsize(void)
1620 {
1621         BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1622                         sizeof(struct compat_ebt_entry_mwt));
1623         return (int) sizeof(struct ebt_entry_match) -
1624                         sizeof(struct compat_ebt_entry_mwt);
1625 }
1626
1627 static int ebt_compat_match_offset(const struct xt_match *match,
1628                                    unsigned int userlen)
1629 {
1630         /* ebt_among needs special handling. The kernel .matchsize is
1631          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1632          * value is expected.
1633          * Example: userspace sends 4500, ebt_among.c wants 4504.
1634          */
1635         if (unlikely(match->matchsize == -1))
1636                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1637         return xt_compat_match_offset(match);
1638 }
1639
1640 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1641                                 unsigned int *size)
1642 {
1643         const struct xt_match *match = m->u.match;
1644         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1645         int off = ebt_compat_match_offset(match, m->match_size);
1646         compat_uint_t msize = m->match_size - off;
1647
1648         if (WARN_ON(off >= m->match_size))
1649                 return -EINVAL;
1650
1651         if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1652             put_user(match->revision, &cm->u.revision) ||
1653             put_user(msize, &cm->match_size))
1654                 return -EFAULT;
1655
1656         if (match->compat_to_user) {
1657                 if (match->compat_to_user(cm->data, m->data))
1658                         return -EFAULT;
1659         } else {
1660                 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1661                                     COMPAT_XT_ALIGN(msize)))
1662                         return -EFAULT;
1663         }
1664
1665         *size -= ebt_compat_entry_padsize() + off;
1666         *dstptr = cm->data;
1667         *dstptr += msize;
1668         return 0;
1669 }
1670
1671 static int compat_target_to_user(struct ebt_entry_target *t,
1672                                  void __user **dstptr,
1673                                  unsigned int *size)
1674 {
1675         const struct xt_target *target = t->u.target;
1676         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1677         int off = xt_compat_target_offset(target);
1678         compat_uint_t tsize = t->target_size - off;
1679
1680         if (WARN_ON(off >= t->target_size))
1681                 return -EINVAL;
1682
1683         if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1684             put_user(target->revision, &cm->u.revision) ||
1685             put_user(tsize, &cm->match_size))
1686                 return -EFAULT;
1687
1688         if (target->compat_to_user) {
1689                 if (target->compat_to_user(cm->data, t->data))
1690                         return -EFAULT;
1691         } else {
1692                 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1693                                     COMPAT_XT_ALIGN(tsize)))
1694                         return -EFAULT;
1695         }
1696
1697         *size -= ebt_compat_entry_padsize() + off;
1698         *dstptr = cm->data;
1699         *dstptr += tsize;
1700         return 0;
1701 }
1702
1703 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1704                                   void __user **dstptr,
1705                                   unsigned int *size)
1706 {
1707         return compat_target_to_user((struct ebt_entry_target *)w,
1708                                                         dstptr, size);
1709 }
1710
1711 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1712                                 unsigned int *size)
1713 {
1714         struct ebt_entry_target *t;
1715         struct ebt_entry __user *ce;
1716         u32 watchers_offset, target_offset, next_offset;
1717         compat_uint_t origsize;
1718         int ret;
1719
1720         if (e->bitmask == 0) {
1721                 if (*size < sizeof(struct ebt_entries))
1722                         return -EINVAL;
1723                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1724                         return -EFAULT;
1725
1726                 *dstptr += sizeof(struct ebt_entries);
1727                 *size -= sizeof(struct ebt_entries);
1728                 return 0;
1729         }
1730
1731         if (*size < sizeof(*ce))
1732                 return -EINVAL;
1733
1734         ce = *dstptr;
1735         if (copy_to_user(ce, e, sizeof(*ce)))
1736                 return -EFAULT;
1737
1738         origsize = *size;
1739         *dstptr += sizeof(*ce);
1740
1741         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1742         if (ret)
1743                 return ret;
1744         watchers_offset = e->watchers_offset - (origsize - *size);
1745
1746         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1747         if (ret)
1748                 return ret;
1749         target_offset = e->target_offset - (origsize - *size);
1750
1751         t = ebt_get_target(e);
1752
1753         ret = compat_target_to_user(t, dstptr, size);
1754         if (ret)
1755                 return ret;
1756         next_offset = e->next_offset - (origsize - *size);
1757
1758         if (put_user(watchers_offset, &ce->watchers_offset) ||
1759             put_user(target_offset, &ce->target_offset) ||
1760             put_user(next_offset, &ce->next_offset))
1761                 return -EFAULT;
1762
1763         *size -= sizeof(*ce);
1764         return 0;
1765 }
1766
1767 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1768 {
1769         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1770         *off += ebt_compat_entry_padsize();
1771         return 0;
1772 }
1773
1774 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1775 {
1776         *off += xt_compat_target_offset(w->u.watcher);
1777         *off += ebt_compat_entry_padsize();
1778         return 0;
1779 }
1780
1781 static int compat_calc_entry(const struct ebt_entry *e,
1782                              const struct ebt_table_info *info,
1783                              const void *base,
1784                              struct compat_ebt_replace *newinfo)
1785 {
1786         const struct ebt_entry_target *t;
1787         unsigned int entry_offset;
1788         int off, ret, i;
1789
1790         if (e->bitmask == 0)
1791                 return 0;
1792
1793         off = 0;
1794         entry_offset = (void *)e - base;
1795
1796         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1797         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1798
1799         t = ebt_get_target_c(e);
1800
1801         off += xt_compat_target_offset(t->u.target);
1802         off += ebt_compat_entry_padsize();
1803
1804         newinfo->entries_size -= off;
1805
1806         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1807         if (ret)
1808                 return ret;
1809
1810         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1811                 const void *hookptr = info->hook_entry[i];
1812                 if (info->hook_entry[i] &&
1813                     (e < (struct ebt_entry *)(base - hookptr))) {
1814                         newinfo->hook_entry[i] -= off;
1815                         pr_debug("0x%08X -> 0x%08X\n",
1816                                         newinfo->hook_entry[i] + off,
1817                                         newinfo->hook_entry[i]);
1818                 }
1819         }
1820
1821         return 0;
1822 }
1823
1824 static int ebt_compat_init_offsets(unsigned int number)
1825 {
1826         if (number > INT_MAX)
1827                 return -EINVAL;
1828
1829         /* also count the base chain policies */
1830         number += NF_BR_NUMHOOKS;
1831
1832         return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1833 }
1834
1835 static int compat_table_info(const struct ebt_table_info *info,
1836                              struct compat_ebt_replace *newinfo)
1837 {
1838         unsigned int size = info->entries_size;
1839         const void *entries = info->entries;
1840         int ret;
1841
1842         newinfo->entries_size = size;
1843         ret = ebt_compat_init_offsets(info->nentries);
1844         if (ret)
1845                 return ret;
1846
1847         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1848                                                         entries, newinfo);
1849 }
1850
1851 static int compat_copy_everything_to_user(struct ebt_table *t,
1852                                           void __user *user, int *len, int cmd)
1853 {
1854         struct compat_ebt_replace repl, tmp;
1855         struct ebt_counter *oldcounters;
1856         struct ebt_table_info tinfo;
1857         int ret;
1858         void __user *pos;
1859
1860         memset(&tinfo, 0, sizeof(tinfo));
1861
1862         if (cmd == EBT_SO_GET_ENTRIES) {
1863                 tinfo.entries_size = t->private->entries_size;
1864                 tinfo.nentries = t->private->nentries;
1865                 tinfo.entries = t->private->entries;
1866                 oldcounters = t->private->counters;
1867         } else {
1868                 tinfo.entries_size = t->table->entries_size;
1869                 tinfo.nentries = t->table->nentries;
1870                 tinfo.entries = t->table->entries;
1871                 oldcounters = t->table->counters;
1872         }
1873
1874         if (copy_from_user(&tmp, user, sizeof(tmp)))
1875                 return -EFAULT;
1876
1877         if (tmp.nentries != tinfo.nentries ||
1878            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1879                 return -EINVAL;
1880
1881         memcpy(&repl, &tmp, sizeof(repl));
1882         if (cmd == EBT_SO_GET_ENTRIES)
1883                 ret = compat_table_info(t->private, &repl);
1884         else
1885                 ret = compat_table_info(&tinfo, &repl);
1886         if (ret)
1887                 return ret;
1888
1889         if (*len != sizeof(tmp) + repl.entries_size +
1890            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1891                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1892                                 *len, tinfo.entries_size, repl.entries_size);
1893                 return -EINVAL;
1894         }
1895
1896         /* userspace might not need the counters */
1897         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1898                                         tmp.num_counters, tinfo.nentries);
1899         if (ret)
1900                 return ret;
1901
1902         pos = compat_ptr(tmp.entries);
1903         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1904                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1905 }
1906
1907 struct ebt_entries_buf_state {
1908         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1909         u32 buf_kern_len;       /* total size of kernel buffer */
1910         u32 buf_kern_offset;    /* amount of data copied so far */
1911         u32 buf_user_offset;    /* read position in userspace buffer */
1912 };
1913
1914 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1915 {
1916         state->buf_kern_offset += sz;
1917         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1918 }
1919
1920 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1921                        const void *data, unsigned int sz)
1922 {
1923         if (state->buf_kern_start == NULL)
1924                 goto count_only;
1925
1926         if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1927                 return -EINVAL;
1928
1929         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1930
1931  count_only:
1932         state->buf_user_offset += sz;
1933         return ebt_buf_count(state, sz);
1934 }
1935
1936 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1937 {
1938         char *b = state->buf_kern_start;
1939
1940         if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1941                 return -EINVAL;
1942
1943         if (b != NULL && sz > 0)
1944                 memset(b + state->buf_kern_offset, 0, sz);
1945         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1946         return ebt_buf_count(state, sz);
1947 }
1948
1949 enum compat_mwt {
1950         EBT_COMPAT_MATCH,
1951         EBT_COMPAT_WATCHER,
1952         EBT_COMPAT_TARGET,
1953 };
1954
1955 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1956                                 enum compat_mwt compat_mwt,
1957                                 struct ebt_entries_buf_state *state,
1958                                 const unsigned char *base)
1959 {
1960         char name[EBT_EXTENSION_MAXNAMELEN];
1961         struct xt_match *match;
1962         struct xt_target *wt;
1963         void *dst = NULL;
1964         int off, pad = 0;
1965         unsigned int size_kern, match_size = mwt->match_size;
1966
1967         if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1968                 return -EINVAL;
1969
1970         if (state->buf_kern_start)
1971                 dst = state->buf_kern_start + state->buf_kern_offset;
1972
1973         switch (compat_mwt) {
1974         case EBT_COMPAT_MATCH:
1975                 match = xt_request_find_match(NFPROTO_BRIDGE, name,
1976                                               mwt->u.revision);
1977                 if (IS_ERR(match))
1978                         return PTR_ERR(match);
1979
1980                 off = ebt_compat_match_offset(match, match_size);
1981                 if (dst) {
1982                         if (match->compat_from_user)
1983                                 match->compat_from_user(dst, mwt->data);
1984                         else
1985                                 memcpy(dst, mwt->data, match_size);
1986                 }
1987
1988                 size_kern = match->matchsize;
1989                 if (unlikely(size_kern == -1))
1990                         size_kern = match_size;
1991                 module_put(match->me);
1992                 break;
1993         case EBT_COMPAT_WATCHER:
1994         case EBT_COMPAT_TARGET:
1995                 wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1996                                             mwt->u.revision);
1997                 if (IS_ERR(wt))
1998                         return PTR_ERR(wt);
1999                 off = xt_compat_target_offset(wt);
2000
2001                 if (dst) {
2002                         if (wt->compat_from_user)
2003                                 wt->compat_from_user(dst, mwt->data);
2004                         else
2005                                 memcpy(dst, mwt->data, match_size);
2006                 }
2007
2008                 size_kern = wt->targetsize;
2009                 module_put(wt->me);
2010                 break;
2011
2012         default:
2013                 return -EINVAL;
2014         }
2015
2016         state->buf_kern_offset += match_size + off;
2017         state->buf_user_offset += match_size;
2018         pad = XT_ALIGN(size_kern) - size_kern;
2019
2020         if (pad > 0 && dst) {
2021                 if (WARN_ON(state->buf_kern_len <= pad))
2022                         return -EINVAL;
2023                 if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2024                         return -EINVAL;
2025                 memset(dst + size_kern, 0, pad);
2026         }
2027         return off + match_size;
2028 }
2029
2030 /* return size of all matches, watchers or target, including necessary
2031  * alignment and padding.
2032  */
2033 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2034                         unsigned int size_left, enum compat_mwt type,
2035                         struct ebt_entries_buf_state *state, const void *base)
2036 {
2037         const char *buf = (const char *)match32;
2038         int growth = 0;
2039
2040         if (size_left == 0)
2041                 return 0;
2042
2043         do {
2044                 struct ebt_entry_match *match_kern;
2045                 int ret;
2046
2047                 if (size_left < sizeof(*match32))
2048                         return -EINVAL;
2049
2050                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2051                 if (match_kern) {
2052                         char *tmp;
2053                         tmp = state->buf_kern_start + state->buf_kern_offset;
2054                         match_kern = (struct ebt_entry_match *) tmp;
2055                 }
2056                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2057                 if (ret < 0)
2058                         return ret;
2059                 size_left -= sizeof(*match32);
2060
2061                 /* add padding before match->data (if any) */
2062                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2063                 if (ret < 0)
2064                         return ret;
2065
2066                 if (match32->match_size > size_left)
2067                         return -EINVAL;
2068
2069                 size_left -= match32->match_size;
2070
2071                 ret = compat_mtw_from_user(match32, type, state, base);
2072                 if (ret < 0)
2073                         return ret;
2074
2075                 if (WARN_ON(ret < match32->match_size))
2076                         return -EINVAL;
2077                 growth += ret - match32->match_size;
2078                 growth += ebt_compat_entry_padsize();
2079
2080                 buf += sizeof(*match32);
2081                 buf += match32->match_size;
2082
2083                 if (match_kern)
2084                         match_kern->match_size = ret;
2085
2086                 match32 = (struct compat_ebt_entry_mwt *) buf;
2087         } while (size_left);
2088
2089         return growth;
2090 }
2091
2092 /* called for all ebt_entry structures. */
2093 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2094                           unsigned int *total,
2095                           struct ebt_entries_buf_state *state)
2096 {
2097         unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2098         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2099         unsigned int offsets[4];
2100         unsigned int *offsets_update = NULL;
2101         int ret;
2102         char *buf_start;
2103
2104         if (*total < sizeof(struct ebt_entries))
2105                 return -EINVAL;
2106
2107         if (!entry->bitmask) {
2108                 *total -= sizeof(struct ebt_entries);
2109                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2110         }
2111         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2112                 return -EINVAL;
2113
2114         startoff = state->buf_user_offset;
2115         /* pull in most part of ebt_entry, it does not need to be changed. */
2116         ret = ebt_buf_add(state, entry,
2117                         offsetof(struct ebt_entry, watchers_offset));
2118         if (ret < 0)
2119                 return ret;
2120
2121         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2122         memcpy(&offsets[1], &entry->offsets, sizeof(entry->offsets));
2123
2124         if (state->buf_kern_start) {
2125                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2126                 offsets_update = (unsigned int *) buf_start;
2127         }
2128         ret = ebt_buf_add(state, &offsets[1],
2129                         sizeof(offsets) - sizeof(offsets[0]));
2130         if (ret < 0)
2131                 return ret;
2132         buf_start = (char *) entry;
2133         /* 0: matches offset, always follows ebt_entry.
2134          * 1: watchers offset, from ebt_entry structure
2135          * 2: target offset, from ebt_entry structure
2136          * 3: next ebt_entry offset, from ebt_entry structure
2137          *
2138          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2139          */
2140         for (i = 0; i < 4 ; ++i) {
2141                 if (offsets[i] > *total)
2142                         return -EINVAL;
2143
2144                 if (i < 3 && offsets[i] == *total)
2145                         return -EINVAL;
2146
2147                 if (i == 0)
2148                         continue;
2149                 if (offsets[i-1] > offsets[i])
2150                         return -EINVAL;
2151         }
2152
2153         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2154                 struct compat_ebt_entry_mwt *match32;
2155                 unsigned int size;
2156                 char *buf = buf_start + offsets[i];
2157
2158                 if (offsets[i] > offsets[j])
2159                         return -EINVAL;
2160
2161                 match32 = (struct compat_ebt_entry_mwt *) buf;
2162                 size = offsets[j] - offsets[i];
2163                 ret = ebt_size_mwt(match32, size, i, state, base);
2164                 if (ret < 0)
2165                         return ret;
2166                 new_offset += ret;
2167                 if (offsets_update && new_offset) {
2168                         pr_debug("change offset %d to %d\n",
2169                                 offsets_update[i], offsets[j] + new_offset);
2170                         offsets_update[i] = offsets[j] + new_offset;
2171                 }
2172         }
2173
2174         if (state->buf_kern_start == NULL) {
2175                 unsigned int offset = buf_start - (char *) base;
2176
2177                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2178                 if (ret < 0)
2179                         return ret;
2180         }
2181
2182         next_expected_off = state->buf_user_offset - startoff;
2183         if (next_expected_off != entry->next_offset)
2184                 return -EINVAL;
2185
2186         if (*total < entry->next_offset)
2187                 return -EINVAL;
2188         *total -= entry->next_offset;
2189         return 0;
2190 }
2191
2192 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2193  * It might need more memory when copied to a 64 bit kernel in case
2194  * userspace is 32-bit. So, first task: find out how much memory is needed.
2195  *
2196  * Called before validation is performed.
2197  */
2198 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2199                                 struct ebt_entries_buf_state *state)
2200 {
2201         unsigned int size_remaining = size_user;
2202         int ret;
2203
2204         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2205                                         &size_remaining, state);
2206         if (ret < 0)
2207                 return ret;
2208
2209         if (size_remaining)
2210                 return -EINVAL;
2211
2212         return state->buf_kern_offset;
2213 }
2214
2215
2216 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2217                                              sockptr_t arg, unsigned int len)
2218 {
2219         struct compat_ebt_replace tmp;
2220         int i;
2221
2222         if (len < sizeof(tmp))
2223                 return -EINVAL;
2224
2225         if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2226                 return -EFAULT;
2227
2228         if (len != sizeof(tmp) + tmp.entries_size)
2229                 return -EINVAL;
2230
2231         if (tmp.entries_size == 0)
2232                 return -EINVAL;
2233
2234         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2235                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2236                 return -ENOMEM;
2237         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2238                 return -ENOMEM;
2239
2240         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2241
2242         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2243         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2244                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2245
2246         repl->num_counters = tmp.num_counters;
2247         repl->counters = compat_ptr(tmp.counters);
2248         repl->entries = compat_ptr(tmp.entries);
2249         return 0;
2250 }
2251
2252 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2253 {
2254         int ret, i, countersize, size64;
2255         struct ebt_table_info *newinfo;
2256         struct ebt_replace tmp;
2257         struct ebt_entries_buf_state state;
2258         void *entries_tmp;
2259
2260         ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2261         if (ret) {
2262                 /* try real handler in case userland supplied needed padding */
2263                 if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2264                         ret = 0;
2265                 return ret;
2266         }
2267
2268         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2269         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2270         if (!newinfo)
2271                 return -ENOMEM;
2272
2273         if (countersize)
2274                 memset(newinfo->counters, 0, countersize);
2275
2276         memset(&state, 0, sizeof(state));
2277
2278         newinfo->entries = vmalloc(tmp.entries_size);
2279         if (!newinfo->entries) {
2280                 ret = -ENOMEM;
2281                 goto free_newinfo;
2282         }
2283         if (copy_from_user(
2284            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2285                 ret = -EFAULT;
2286                 goto free_entries;
2287         }
2288
2289         entries_tmp = newinfo->entries;
2290
2291         xt_compat_lock(NFPROTO_BRIDGE);
2292
2293         ret = ebt_compat_init_offsets(tmp.nentries);
2294         if (ret < 0)
2295                 goto out_unlock;
2296
2297         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2298         if (ret < 0)
2299                 goto out_unlock;
2300
2301         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2302                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2303                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2304
2305         size64 = ret;
2306         newinfo->entries = vmalloc(size64);
2307         if (!newinfo->entries) {
2308                 vfree(entries_tmp);
2309                 ret = -ENOMEM;
2310                 goto out_unlock;
2311         }
2312
2313         memset(&state, 0, sizeof(state));
2314         state.buf_kern_start = newinfo->entries;
2315         state.buf_kern_len = size64;
2316
2317         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2318         if (WARN_ON(ret < 0)) {
2319                 vfree(entries_tmp);
2320                 goto out_unlock;
2321         }
2322
2323         vfree(entries_tmp);
2324         tmp.entries_size = size64;
2325
2326         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2327                 char __user *usrptr;
2328                 if (tmp.hook_entry[i]) {
2329                         unsigned int delta;
2330                         usrptr = (char __user *) tmp.hook_entry[i];
2331                         delta = usrptr - tmp.entries;
2332                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2333                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2334                 }
2335         }
2336
2337         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2338         xt_compat_unlock(NFPROTO_BRIDGE);
2339
2340         ret = do_replace_finish(net, &tmp, newinfo);
2341         if (ret == 0)
2342                 return ret;
2343 free_entries:
2344         vfree(newinfo->entries);
2345 free_newinfo:
2346         vfree(newinfo);
2347         return ret;
2348 out_unlock:
2349         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2350         xt_compat_unlock(NFPROTO_BRIDGE);
2351         goto free_entries;
2352 }
2353
2354 static int compat_update_counters(struct net *net, sockptr_t arg,
2355                                   unsigned int len)
2356 {
2357         struct compat_ebt_replace hlp;
2358
2359         if (len < sizeof(hlp))
2360                 return -EINVAL;
2361         if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2362                 return -EFAULT;
2363
2364         /* try real handler in case userland supplied needed padding */
2365         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2366                 return update_counters(net, arg, len);
2367
2368         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2369                                   hlp.num_counters, len);
2370 }
2371
2372 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2373                 void __user *user, int *len)
2374 {
2375         int ret;
2376         struct compat_ebt_replace tmp;
2377         struct ebt_table *t;
2378         struct net *net = sock_net(sk);
2379
2380         if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2381             *len != sizeof(struct compat_ebt_replace))
2382                 return -EINVAL;
2383
2384         if (copy_from_user(&tmp, user, sizeof(tmp)))
2385                 return -EFAULT;
2386
2387         tmp.name[sizeof(tmp.name) - 1] = '\0';
2388
2389         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2390         if (!t)
2391                 return ret;
2392
2393         xt_compat_lock(NFPROTO_BRIDGE);
2394         switch (cmd) {
2395         case EBT_SO_GET_INFO:
2396                 tmp.nentries = t->private->nentries;
2397                 ret = compat_table_info(t->private, &tmp);
2398                 if (ret)
2399                         goto out;
2400                 tmp.valid_hooks = t->valid_hooks;
2401
2402                 if (copy_to_user(user, &tmp, *len) != 0) {
2403                         ret = -EFAULT;
2404                         break;
2405                 }
2406                 ret = 0;
2407                 break;
2408         case EBT_SO_GET_INIT_INFO:
2409                 tmp.nentries = t->table->nentries;
2410                 tmp.entries_size = t->table->entries_size;
2411                 tmp.valid_hooks = t->table->valid_hooks;
2412
2413                 if (copy_to_user(user, &tmp, *len) != 0) {
2414                         ret = -EFAULT;
2415                         break;
2416                 }
2417                 ret = 0;
2418                 break;
2419         case EBT_SO_GET_ENTRIES:
2420         case EBT_SO_GET_INIT_ENTRIES:
2421                 /* try real handler first in case of userland-side padding.
2422                  * in case we are dealing with an 'ordinary' 32 bit binary
2423                  * without 64bit compatibility padding, this will fail right
2424                  * after copy_from_user when the *len argument is validated.
2425                  *
2426                  * the compat_ variant needs to do one pass over the kernel
2427                  * data set to adjust for size differences before it the check.
2428                  */
2429                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2430                         ret = 0;
2431                 else
2432                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2433                 break;
2434         default:
2435                 ret = -EINVAL;
2436         }
2437  out:
2438         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2439         xt_compat_unlock(NFPROTO_BRIDGE);
2440         mutex_unlock(&ebt_mutex);
2441         return ret;
2442 }
2443 #endif
2444
2445 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2446 {
2447         struct net *net = sock_net(sk);
2448         struct ebt_replace tmp;
2449         struct ebt_table *t;
2450         int ret;
2451
2452         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2453                 return -EPERM;
2454
2455 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2456         /* try real handler in case userland supplied needed padding */
2457         if (in_compat_syscall() &&
2458             ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2459              *len != sizeof(tmp)))
2460                 return compat_do_ebt_get_ctl(sk, cmd, user, len);
2461 #endif
2462
2463         if (copy_from_user(&tmp, user, sizeof(tmp)))
2464                 return -EFAULT;
2465
2466         tmp.name[sizeof(tmp.name) - 1] = '\0';
2467
2468         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2469         if (!t)
2470                 return ret;
2471
2472         switch (cmd) {
2473         case EBT_SO_GET_INFO:
2474         case EBT_SO_GET_INIT_INFO:
2475                 if (*len != sizeof(struct ebt_replace)) {
2476                         ret = -EINVAL;
2477                         mutex_unlock(&ebt_mutex);
2478                         break;
2479                 }
2480                 if (cmd == EBT_SO_GET_INFO) {
2481                         tmp.nentries = t->private->nentries;
2482                         tmp.entries_size = t->private->entries_size;
2483                         tmp.valid_hooks = t->valid_hooks;
2484                 } else {
2485                         tmp.nentries = t->table->nentries;
2486                         tmp.entries_size = t->table->entries_size;
2487                         tmp.valid_hooks = t->table->valid_hooks;
2488                 }
2489                 mutex_unlock(&ebt_mutex);
2490                 if (copy_to_user(user, &tmp, *len) != 0) {
2491                         ret = -EFAULT;
2492                         break;
2493                 }
2494                 ret = 0;
2495                 break;
2496
2497         case EBT_SO_GET_ENTRIES:
2498         case EBT_SO_GET_INIT_ENTRIES:
2499                 ret = copy_everything_to_user(t, user, len, cmd);
2500                 mutex_unlock(&ebt_mutex);
2501                 break;
2502
2503         default:
2504                 mutex_unlock(&ebt_mutex);
2505                 ret = -EINVAL;
2506         }
2507
2508         return ret;
2509 }
2510
2511 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2512                 unsigned int len)
2513 {
2514         struct net *net = sock_net(sk);
2515         int ret;
2516
2517         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2518                 return -EPERM;
2519
2520         switch (cmd) {
2521         case EBT_SO_SET_ENTRIES:
2522 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2523                 if (in_compat_syscall())
2524                         ret = compat_do_replace(net, arg, len);
2525                 else
2526 #endif
2527                         ret = do_replace(net, arg, len);
2528                 break;
2529         case EBT_SO_SET_COUNTERS:
2530 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2531                 if (in_compat_syscall())
2532                         ret = compat_update_counters(net, arg, len);
2533                 else
2534 #endif
2535                         ret = update_counters(net, arg, len);
2536                 break;
2537         default:
2538                 ret = -EINVAL;
2539         }
2540         return ret;
2541 }
2542
2543 static struct nf_sockopt_ops ebt_sockopts = {
2544         .pf             = PF_INET,
2545         .set_optmin     = EBT_BASE_CTL,
2546         .set_optmax     = EBT_SO_SET_MAX + 1,
2547         .set            = do_ebt_set_ctl,
2548         .get_optmin     = EBT_BASE_CTL,
2549         .get_optmax     = EBT_SO_GET_MAX + 1,
2550         .get            = do_ebt_get_ctl,
2551         .owner          = THIS_MODULE,
2552 };
2553
2554 static int __net_init ebt_pernet_init(struct net *net)
2555 {
2556         struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2557
2558         INIT_LIST_HEAD(&ebt_net->tables);
2559         return 0;
2560 }
2561
2562 static struct pernet_operations ebt_net_ops = {
2563         .init = ebt_pernet_init,
2564         .id   = &ebt_pernet_id,
2565         .size = sizeof(struct ebt_pernet),
2566 };
2567
2568 static int __init ebtables_init(void)
2569 {
2570         int ret;
2571
2572         ret = xt_register_target(&ebt_standard_target);
2573         if (ret < 0)
2574                 return ret;
2575         ret = nf_register_sockopt(&ebt_sockopts);
2576         if (ret < 0) {
2577                 xt_unregister_target(&ebt_standard_target);
2578                 return ret;
2579         }
2580
2581         ret = register_pernet_subsys(&ebt_net_ops);
2582         if (ret < 0) {
2583                 nf_unregister_sockopt(&ebt_sockopts);
2584                 xt_unregister_target(&ebt_standard_target);
2585                 return ret;
2586         }
2587
2588         return 0;
2589 }
2590
2591 static void ebtables_fini(void)
2592 {
2593         nf_unregister_sockopt(&ebt_sockopts);
2594         xt_unregister_target(&ebt_standard_target);
2595         unregister_pernet_subsys(&ebt_net_ops);
2596 }
2597
2598 EXPORT_SYMBOL(ebt_register_table);
2599 EXPORT_SYMBOL(ebt_unregister_table);
2600 EXPORT_SYMBOL(ebt_do_table);
2601 module_init(ebtables_init);
2602 module_exit(ebtables_fini);
2603 MODULE_LICENSE("GPL");
2604 MODULE_DESCRIPTION("ebtables legacy core");