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Linux/net/bridge/netfilter/ebtables.c

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  1 /*
  2  *  ebtables
  3  *
  4  *  Author:
  5  *  Bart De Schuymer            <bdschuym@pandora.be>
  6  *
  7  *  ebtables.c,v 2.0, July, 2002
  8  *
  9  *  This code is strongly inspired by the iptables code which is
 10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 11  *
 12  *  This program is free software; you can redistribute it and/or
 13  *  modify it under the terms of the GNU General Public License
 14  *  as published by the Free Software Foundation; either version
 15  *  2 of the License, or (at your option) any later version.
 16  */
 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 18 #include <linux/kmod.h>
 19 #include <linux/module.h>
 20 #include <linux/vmalloc.h>
 21 #include <linux/netfilter/x_tables.h>
 22 #include <linux/netfilter_bridge/ebtables.h>
 23 #include <linux/spinlock.h>
 24 #include <linux/mutex.h>
 25 #include <linux/slab.h>
 26 #include <asm/uaccess.h>
 27 #include <linux/smp.h>
 28 #include <linux/cpumask.h>
 29 #include <linux/audit.h>
 30 #include <net/sock.h>
 31 /* needed for logical [in,out]-dev filtering */
 32 #include "../br_private.h"
 33 
 34 #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\
 35                                          "report to author: "format, ## args)
 36 /* #define BUGPRINT(format, args...) */
 37 
 38 /* Each cpu has its own set of counters, so there is no need for write_lock in
 39  * the softirq
 40  * For reading or updating the counters, the user context needs to
 41  * get a write_lock
 42  */
 43 
 44 /* The size of each set of counters is altered to get cache alignment */
 45 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
 46 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
 47 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
 48                                  COUNTER_OFFSET(n) * cpu))
 49 
 50 
 51 
 52 static DEFINE_MUTEX(ebt_mutex);
 53 
 54 #ifdef CONFIG_COMPAT
 55 static void ebt_standard_compat_from_user(void *dst, const void *src)
 56 {
 57         int v = *(compat_int_t *)src;
 58 
 59         if (v >= 0)
 60                 v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
 61         memcpy(dst, &v, sizeof(v));
 62 }
 63 
 64 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
 65 {
 66         compat_int_t cv = *(int *)src;
 67 
 68         if (cv >= 0)
 69                 cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
 70         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 71 }
 72 #endif
 73 
 74 
 75 static struct xt_target ebt_standard_target = {
 76         .name       = "standard",
 77         .revision   = 0,
 78         .family     = NFPROTO_BRIDGE,
 79         .targetsize = sizeof(int),
 80 #ifdef CONFIG_COMPAT
 81         .compatsize = sizeof(compat_int_t),
 82         .compat_from_user = ebt_standard_compat_from_user,
 83         .compat_to_user =  ebt_standard_compat_to_user,
 84 #endif
 85 };
 86 
 87 static inline int
 88 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
 89                struct xt_action_param *par)
 90 {
 91         par->target   = w->u.watcher;
 92         par->targinfo = w->data;
 93         w->u.watcher->target(skb, par);
 94         /* watchers don't give a verdict */
 95         return 0;
 96 }
 97 
 98 static inline int
 99 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
100              struct xt_action_param *par)
101 {
102         par->match     = m->u.match;
103         par->matchinfo = m->data;
104         return m->u.match->match(skb, par) ? EBT_MATCH : EBT_NOMATCH;
105 }
106 
107 static inline int
108 ebt_dev_check(const char *entry, const struct net_device *device)
109 {
110         int i = 0;
111         const char *devname;
112 
113         if (*entry == '\0')
114                 return 0;
115         if (!device)
116                 return 1;
117         devname = device->name;
118         /* 1 is the wildcard token */
119         while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
120                 i++;
121         return devname[i] != entry[i] && entry[i] != 1;
122 }
123 
124 #define FWINV2(bool, invflg) ((bool) ^ !!(e->invflags & invflg))
125 /* process standard matches */
126 static inline int
127 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
128                 const struct net_device *in, const struct net_device *out)
129 {
130         const struct ethhdr *h = eth_hdr(skb);
131         const struct net_bridge_port *p;
132         __be16 ethproto;
133         int verdict, i;
134 
135         if (skb_vlan_tag_present(skb))
136                 ethproto = htons(ETH_P_8021Q);
137         else
138                 ethproto = h->h_proto;
139 
140         if (e->bitmask & EBT_802_3) {
141                 if (FWINV2(eth_proto_is_802_3(ethproto), EBT_IPROTO))
142                         return 1;
143         } else if (!(e->bitmask & EBT_NOPROTO) &&
144            FWINV2(e->ethproto != ethproto, EBT_IPROTO))
145                 return 1;
146 
147         if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN))
148                 return 1;
149         if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
150                 return 1;
151         /* rcu_read_lock()ed by nf_hook_slow */
152         if (in && (p = br_port_get_rcu(in)) != NULL &&
153             FWINV2(ebt_dev_check(e->logical_in, p->br->dev), EBT_ILOGICALIN))
154                 return 1;
155         if (out && (p = br_port_get_rcu(out)) != NULL &&
156             FWINV2(ebt_dev_check(e->logical_out, p->br->dev), EBT_ILOGICALOUT))
157                 return 1;
158 
159         if (e->bitmask & EBT_SOURCEMAC) {
160                 verdict = 0;
161                 for (i = 0; i < 6; i++)
162                         verdict |= (h->h_source[i] ^ e->sourcemac[i]) &
163                            e->sourcemsk[i];
164                 if (FWINV2(verdict != 0, EBT_ISOURCE))
165                         return 1;
166         }
167         if (e->bitmask & EBT_DESTMAC) {
168                 verdict = 0;
169                 for (i = 0; i < 6; i++)
170                         verdict |= (h->h_dest[i] ^ e->destmac[i]) &
171                            e->destmsk[i];
172                 if (FWINV2(verdict != 0, EBT_IDEST))
173                         return 1;
174         }
175         return 0;
176 }
177 
178 static inline
179 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
180 {
181         return (void *)entry + entry->next_offset;
182 }
183 
184 /* Do some firewalling */
185 unsigned int ebt_do_table(struct sk_buff *skb,
186                           const struct nf_hook_state *state,
187                           struct ebt_table *table)
188 {
189         unsigned int hook = state->hook;
190         int i, nentries;
191         struct ebt_entry *point;
192         struct ebt_counter *counter_base, *cb_base;
193         const struct ebt_entry_target *t;
194         int verdict, sp = 0;
195         struct ebt_chainstack *cs;
196         struct ebt_entries *chaininfo;
197         const char *base;
198         const struct ebt_table_info *private;
199         struct xt_action_param acpar;
200 
201         acpar.family  = NFPROTO_BRIDGE;
202         acpar.net     = state->net;
203         acpar.in      = state->in;
204         acpar.out     = state->out;
205         acpar.hotdrop = false;
206         acpar.hooknum = hook;
207 
208         read_lock_bh(&table->lock);
209         private = table->private;
210         cb_base = COUNTER_BASE(private->counters, private->nentries,
211            smp_processor_id());
212         if (private->chainstack)
213                 cs = private->chainstack[smp_processor_id()];
214         else
215                 cs = NULL;
216         chaininfo = private->hook_entry[hook];
217         nentries = private->hook_entry[hook]->nentries;
218         point = (struct ebt_entry *)(private->hook_entry[hook]->data);
219         counter_base = cb_base + private->hook_entry[hook]->counter_offset;
220         /* base for chain jumps */
221         base = private->entries;
222         i = 0;
223         while (i < nentries) {
224                 if (ebt_basic_match(point, skb, state->in, state->out))
225                         goto letscontinue;
226 
227                 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
228                         goto letscontinue;
229                 if (acpar.hotdrop) {
230                         read_unlock_bh(&table->lock);
231                         return NF_DROP;
232                 }
233 
234                 /* increase counter */
235                 (*(counter_base + i)).pcnt++;
236                 (*(counter_base + i)).bcnt += skb->len;
237 
238                 /* these should only watch: not modify, nor tell us
239                  * what to do with the packet
240                  */
241                 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
242 
243                 t = (struct ebt_entry_target *)
244                    (((char *)point) + point->target_offset);
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 #ifdef CONFIG_NETFILTER_DEBUG
264                         if (sp == 0) {
265                                 BUGPRINT("RETURN on base chain");
266                                 /* act like this is EBT_CONTINUE */
267                                 goto letscontinue;
268                         }
269 #endif
270                         sp--;
271                         /* put all the local variables right */
272                         i = cs[sp].n;
273                         chaininfo = cs[sp].chaininfo;
274                         nentries = chaininfo->nentries;
275                         point = cs[sp].e;
276                         counter_base = cb_base +
277                            chaininfo->counter_offset;
278                         continue;
279                 }
280                 if (verdict == EBT_CONTINUE)
281                         goto letscontinue;
282 #ifdef CONFIG_NETFILTER_DEBUG
283                 if (verdict < 0) {
284                         BUGPRINT("bogus standard verdict\n");
285                         read_unlock_bh(&table->lock);
286                         return NF_DROP;
287                 }
288 #endif
289                 /* jump to a udc */
290                 cs[sp].n = i + 1;
291                 cs[sp].chaininfo = chaininfo;
292                 cs[sp].e = ebt_next_entry(point);
293                 i = 0;
294                 chaininfo = (struct ebt_entries *) (base + verdict);
295 #ifdef CONFIG_NETFILTER_DEBUG
296                 if (chaininfo->distinguisher) {
297                         BUGPRINT("jump to non-chain\n");
298                         read_unlock_bh(&table->lock);
299                         return NF_DROP;
300                 }
301 #endif
302                 nentries = chaininfo->nentries;
303                 point = (struct ebt_entry *)chaininfo->data;
304                 counter_base = cb_base + chaininfo->counter_offset;
305                 sp++;
306                 continue;
307 letscontinue:
308                 point = ebt_next_entry(point);
309                 i++;
310         }
311 
312         /* I actually like this :) */
313         if (chaininfo->policy == EBT_RETURN)
314                 goto letsreturn;
315         if (chaininfo->policy == EBT_ACCEPT) {
316                 read_unlock_bh(&table->lock);
317                 return NF_ACCEPT;
318         }
319         read_unlock_bh(&table->lock);
320         return NF_DROP;
321 }
322 
323 /* If it succeeds, returns element and locks mutex */
324 static inline void *
325 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
326                         struct mutex *mutex)
327 {
328         struct {
329                 struct list_head list;
330                 char name[EBT_FUNCTION_MAXNAMELEN];
331         } *e;
332 
333         mutex_lock(mutex);
334         list_for_each_entry(e, head, list) {
335                 if (strcmp(e->name, name) == 0)
336                         return e;
337         }
338         *error = -ENOENT;
339         mutex_unlock(mutex);
340         return NULL;
341 }
342 
343 static void *
344 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
345                  int *error, struct mutex *mutex)
346 {
347         return try_then_request_module(
348                         find_inlist_lock_noload(head, name, error, mutex),
349                         "%s%s", prefix, name);
350 }
351 
352 static inline struct ebt_table *
353 find_table_lock(struct net *net, const char *name, int *error,
354                 struct mutex *mutex)
355 {
356         return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
357                                 "ebtable_", error, mutex);
358 }
359 
360 static inline int
361 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
362                 unsigned int *cnt)
363 {
364         const struct ebt_entry *e = par->entryinfo;
365         struct xt_match *match;
366         size_t left = ((char *)e + e->watchers_offset) - (char *)m;
367         int ret;
368 
369         if (left < sizeof(struct ebt_entry_match) ||
370             left - sizeof(struct ebt_entry_match) < m->match_size)
371                 return -EINVAL;
372 
373         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
374         if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
375                 request_module("ebt_%s", m->u.name);
376                 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
377         }
378         if (IS_ERR(match))
379                 return PTR_ERR(match);
380         m->u.match = match;
381 
382         par->match     = match;
383         par->matchinfo = m->data;
384         ret = xt_check_match(par, m->match_size,
385               e->ethproto, e->invflags & EBT_IPROTO);
386         if (ret < 0) {
387                 module_put(match->me);
388                 return ret;
389         }
390 
391         (*cnt)++;
392         return 0;
393 }
394 
395 static inline int
396 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
397                   unsigned int *cnt)
398 {
399         const struct ebt_entry *e = par->entryinfo;
400         struct xt_target *watcher;
401         size_t left = ((char *)e + e->target_offset) - (char *)w;
402         int ret;
403 
404         if (left < sizeof(struct ebt_entry_watcher) ||
405            left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
406                 return -EINVAL;
407 
408         watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
409         if (IS_ERR(watcher))
410                 return PTR_ERR(watcher);
411         w->u.watcher = watcher;
412 
413         par->target   = watcher;
414         par->targinfo = w->data;
415         ret = xt_check_target(par, w->watcher_size,
416               e->ethproto, e->invflags & EBT_IPROTO);
417         if (ret < 0) {
418                 module_put(watcher->me);
419                 return ret;
420         }
421 
422         (*cnt)++;
423         return 0;
424 }
425 
426 static int ebt_verify_pointers(const struct ebt_replace *repl,
427                                struct ebt_table_info *newinfo)
428 {
429         unsigned int limit = repl->entries_size;
430         unsigned int valid_hooks = repl->valid_hooks;
431         unsigned int offset = 0;
432         int i;
433 
434         for (i = 0; i < NF_BR_NUMHOOKS; i++)
435                 newinfo->hook_entry[i] = NULL;
436 
437         newinfo->entries_size = repl->entries_size;
438         newinfo->nentries = repl->nentries;
439 
440         while (offset < limit) {
441                 size_t left = limit - offset;
442                 struct ebt_entry *e = (void *)newinfo->entries + offset;
443 
444                 if (left < sizeof(unsigned int))
445                         break;
446 
447                 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
448                         if ((valid_hooks & (1 << i)) == 0)
449                                 continue;
450                         if ((char __user *)repl->hook_entry[i] ==
451                              repl->entries + offset)
452                                 break;
453                 }
454 
455                 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
456                         if (e->bitmask != 0) {
457                                 /* we make userspace set this right,
458                                  * so there is no misunderstanding
459                                  */
460                                 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
461                                          "in distinguisher\n");
462                                 return -EINVAL;
463                         }
464                         if (i != NF_BR_NUMHOOKS)
465                                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
466                         if (left < sizeof(struct ebt_entries))
467                                 break;
468                         offset += sizeof(struct ebt_entries);
469                 } else {
470                         if (left < sizeof(struct ebt_entry))
471                                 break;
472                         if (left < e->next_offset)
473                                 break;
474                         if (e->next_offset < sizeof(struct ebt_entry))
475                                 return -EINVAL;
476                         offset += e->next_offset;
477                 }
478         }
479         if (offset != limit) {
480                 BUGPRINT("entries_size too small\n");
481                 return -EINVAL;
482         }
483 
484         /* check if all valid hooks have a chain */
485         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
486                 if (!newinfo->hook_entry[i] &&
487                    (valid_hooks & (1 << i))) {
488                         BUGPRINT("Valid hook without chain\n");
489                         return -EINVAL;
490                 }
491         }
492         return 0;
493 }
494 
495 /* this one is very careful, as it is the first function
496  * to parse the userspace data
497  */
498 static inline int
499 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
500                                const struct ebt_table_info *newinfo,
501                                unsigned int *n, unsigned int *cnt,
502                                unsigned int *totalcnt, unsigned int *udc_cnt)
503 {
504         int i;
505 
506         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
507                 if ((void *)e == (void *)newinfo->hook_entry[i])
508                         break;
509         }
510         /* beginning of a new chain
511          * if i == NF_BR_NUMHOOKS it must be a user defined chain
512          */
513         if (i != NF_BR_NUMHOOKS || !e->bitmask) {
514                 /* this checks if the previous chain has as many entries
515                  * as it said it has
516                  */
517                 if (*n != *cnt) {
518                         BUGPRINT("nentries does not equal the nr of entries "
519                                  "in the chain\n");
520                         return -EINVAL;
521                 }
522                 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
523                    ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
524                         /* only RETURN from udc */
525                         if (i != NF_BR_NUMHOOKS ||
526                            ((struct ebt_entries *)e)->policy != EBT_RETURN) {
527                                 BUGPRINT("bad policy\n");
528                                 return -EINVAL;
529                         }
530                 }
531                 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
532                         (*udc_cnt)++;
533                 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
534                         BUGPRINT("counter_offset != totalcnt");
535                         return -EINVAL;
536                 }
537                 *n = ((struct ebt_entries *)e)->nentries;
538                 *cnt = 0;
539                 return 0;
540         }
541         /* a plain old entry, heh */
542         if (sizeof(struct ebt_entry) > e->watchers_offset ||
543            e->watchers_offset > e->target_offset ||
544            e->target_offset >= e->next_offset) {
545                 BUGPRINT("entry offsets not in right order\n");
546                 return -EINVAL;
547         }
548         /* this is not checked anywhere else */
549         if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
550                 BUGPRINT("target size too small\n");
551                 return -EINVAL;
552         }
553         (*cnt)++;
554         (*totalcnt)++;
555         return 0;
556 }
557 
558 struct ebt_cl_stack {
559         struct ebt_chainstack cs;
560         int from;
561         unsigned int hookmask;
562 };
563 
564 /* We need these positions to check that the jumps to a different part of the
565  * entries is a jump to the beginning of a new chain.
566  */
567 static inline int
568 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
569                       unsigned int *n, struct ebt_cl_stack *udc)
570 {
571         int i;
572 
573         /* we're only interested in chain starts */
574         if (e->bitmask)
575                 return 0;
576         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
577                 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
578                         break;
579         }
580         /* only care about udc */
581         if (i != NF_BR_NUMHOOKS)
582                 return 0;
583 
584         udc[*n].cs.chaininfo = (struct ebt_entries *)e;
585         /* these initialisations are depended on later in check_chainloops() */
586         udc[*n].cs.n = 0;
587         udc[*n].hookmask = 0;
588 
589         (*n)++;
590         return 0;
591 }
592 
593 static inline int
594 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
595 {
596         struct xt_mtdtor_param par;
597 
598         if (i && (*i)-- == 0)
599                 return 1;
600 
601         par.net       = net;
602         par.match     = m->u.match;
603         par.matchinfo = m->data;
604         par.family    = NFPROTO_BRIDGE;
605         if (par.match->destroy != NULL)
606                 par.match->destroy(&par);
607         module_put(par.match->me);
608         return 0;
609 }
610 
611 static inline int
612 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
613 {
614         struct xt_tgdtor_param par;
615 
616         if (i && (*i)-- == 0)
617                 return 1;
618 
619         par.net      = net;
620         par.target   = w->u.watcher;
621         par.targinfo = w->data;
622         par.family   = NFPROTO_BRIDGE;
623         if (par.target->destroy != NULL)
624                 par.target->destroy(&par);
625         module_put(par.target->me);
626         return 0;
627 }
628 
629 static inline int
630 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
631 {
632         struct xt_tgdtor_param par;
633         struct ebt_entry_target *t;
634 
635         if (e->bitmask == 0)
636                 return 0;
637         /* we're done */
638         if (cnt && (*cnt)-- == 0)
639                 return 1;
640         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
641         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
642         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
643 
644         par.net      = net;
645         par.target   = t->u.target;
646         par.targinfo = t->data;
647         par.family   = NFPROTO_BRIDGE;
648         if (par.target->destroy != NULL)
649                 par.target->destroy(&par);
650         module_put(par.target->me);
651         return 0;
652 }
653 
654 static inline int
655 ebt_check_entry(struct ebt_entry *e, struct net *net,
656                 const struct ebt_table_info *newinfo,
657                 const char *name, unsigned int *cnt,
658                 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
659 {
660         struct ebt_entry_target *t;
661         struct xt_target *target;
662         unsigned int i, j, hook = 0, hookmask = 0;
663         size_t gap;
664         int ret;
665         struct xt_mtchk_param mtpar;
666         struct xt_tgchk_param tgpar;
667 
668         /* don't mess with the struct ebt_entries */
669         if (e->bitmask == 0)
670                 return 0;
671 
672         if (e->bitmask & ~EBT_F_MASK) {
673                 BUGPRINT("Unknown flag for bitmask\n");
674                 return -EINVAL;
675         }
676         if (e->invflags & ~EBT_INV_MASK) {
677                 BUGPRINT("Unknown flag for inv bitmask\n");
678                 return -EINVAL;
679         }
680         if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
681                 BUGPRINT("NOPROTO & 802_3 not allowed\n");
682                 return -EINVAL;
683         }
684         /* what hook do we belong to? */
685         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
686                 if (!newinfo->hook_entry[i])
687                         continue;
688                 if ((char *)newinfo->hook_entry[i] < (char *)e)
689                         hook = i;
690                 else
691                         break;
692         }
693         /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
694          * a base chain
695          */
696         if (i < NF_BR_NUMHOOKS)
697                 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
698         else {
699                 for (i = 0; i < udc_cnt; i++)
700                         if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
701                                 break;
702                 if (i == 0)
703                         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
704                 else
705                         hookmask = cl_s[i - 1].hookmask;
706         }
707         i = 0;
708 
709         mtpar.net       = tgpar.net       = net;
710         mtpar.table     = tgpar.table     = name;
711         mtpar.entryinfo = tgpar.entryinfo = e;
712         mtpar.hook_mask = tgpar.hook_mask = hookmask;
713         mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
714         ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
715         if (ret != 0)
716                 goto cleanup_matches;
717         j = 0;
718         ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
719         if (ret != 0)
720                 goto cleanup_watchers;
721         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
722         gap = e->next_offset - e->target_offset;
723 
724         target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
725         if (IS_ERR(target)) {
726                 ret = PTR_ERR(target);
727                 goto cleanup_watchers;
728         }
729 
730         t->u.target = target;
731         if (t->u.target == &ebt_standard_target) {
732                 if (gap < sizeof(struct ebt_standard_target)) {
733                         BUGPRINT("Standard target size too big\n");
734                         ret = -EFAULT;
735                         goto cleanup_watchers;
736                 }
737                 if (((struct ebt_standard_target *)t)->verdict <
738                    -NUM_STANDARD_TARGETS) {
739                         BUGPRINT("Invalid standard target\n");
740                         ret = -EFAULT;
741                         goto cleanup_watchers;
742                 }
743         } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
744                 module_put(t->u.target->me);
745                 ret = -EFAULT;
746                 goto cleanup_watchers;
747         }
748 
749         tgpar.target   = target;
750         tgpar.targinfo = t->data;
751         ret = xt_check_target(&tgpar, t->target_size,
752               e->ethproto, e->invflags & EBT_IPROTO);
753         if (ret < 0) {
754                 module_put(target->me);
755                 goto cleanup_watchers;
756         }
757         (*cnt)++;
758         return 0;
759 cleanup_watchers:
760         EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
761 cleanup_matches:
762         EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
763         return ret;
764 }
765 
766 /* checks for loops and sets the hook mask for udc
767  * the hook mask for udc tells us from which base chains the udc can be
768  * accessed. This mask is a parameter to the check() functions of the extensions
769  */
770 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
771                             unsigned int udc_cnt, unsigned int hooknr, char *base)
772 {
773         int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
774         const struct ebt_entry *e = (struct ebt_entry *)chain->data;
775         const struct ebt_entry_target *t;
776 
777         while (pos < nentries || chain_nr != -1) {
778                 /* end of udc, go back one 'recursion' step */
779                 if (pos == nentries) {
780                         /* put back values of the time when this chain was called */
781                         e = cl_s[chain_nr].cs.e;
782                         if (cl_s[chain_nr].from != -1)
783                                 nentries =
784                                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
785                         else
786                                 nentries = chain->nentries;
787                         pos = cl_s[chain_nr].cs.n;
788                         /* make sure we won't see a loop that isn't one */
789                         cl_s[chain_nr].cs.n = 0;
790                         chain_nr = cl_s[chain_nr].from;
791                         if (pos == nentries)
792                                 continue;
793                 }
794                 t = (struct ebt_entry_target *)
795                    (((char *)e) + e->target_offset);
796                 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
797                         goto letscontinue;
798                 if (e->target_offset + sizeof(struct ebt_standard_target) >
799                    e->next_offset) {
800                         BUGPRINT("Standard target size too big\n");
801                         return -1;
802                 }
803                 verdict = ((struct ebt_standard_target *)t)->verdict;
804                 if (verdict >= 0) { /* jump to another chain */
805                         struct ebt_entries *hlp2 =
806                            (struct ebt_entries *)(base + verdict);
807                         for (i = 0; i < udc_cnt; i++)
808                                 if (hlp2 == cl_s[i].cs.chaininfo)
809                                         break;
810                         /* bad destination or loop */
811                         if (i == udc_cnt) {
812                                 BUGPRINT("bad destination\n");
813                                 return -1;
814                         }
815                         if (cl_s[i].cs.n) {
816                                 BUGPRINT("loop\n");
817                                 return -1;
818                         }
819                         if (cl_s[i].hookmask & (1 << hooknr))
820                                 goto letscontinue;
821                         /* this can't be 0, so the loop test is correct */
822                         cl_s[i].cs.n = pos + 1;
823                         pos = 0;
824                         cl_s[i].cs.e = ebt_next_entry(e);
825                         e = (struct ebt_entry *)(hlp2->data);
826                         nentries = hlp2->nentries;
827                         cl_s[i].from = chain_nr;
828                         chain_nr = i;
829                         /* this udc is accessible from the base chain for hooknr */
830                         cl_s[i].hookmask |= (1 << hooknr);
831                         continue;
832                 }
833 letscontinue:
834                 e = ebt_next_entry(e);
835                 pos++;
836         }
837         return 0;
838 }
839 
840 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
841 static int translate_table(struct net *net, const char *name,
842                            struct ebt_table_info *newinfo)
843 {
844         unsigned int i, j, k, udc_cnt;
845         int ret;
846         struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
847 
848         i = 0;
849         while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
850                 i++;
851         if (i == NF_BR_NUMHOOKS) {
852                 BUGPRINT("No valid hooks specified\n");
853                 return -EINVAL;
854         }
855         if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
856                 BUGPRINT("Chains don't start at beginning\n");
857                 return -EINVAL;
858         }
859         /* make sure chains are ordered after each other in same order
860          * as their corresponding hooks
861          */
862         for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
863                 if (!newinfo->hook_entry[j])
864                         continue;
865                 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
866                         BUGPRINT("Hook order must be followed\n");
867                         return -EINVAL;
868                 }
869                 i = j;
870         }
871 
872         /* do some early checkings and initialize some things */
873         i = 0; /* holds the expected nr. of entries for the chain */
874         j = 0; /* holds the up to now counted entries for the chain */
875         k = 0; /* holds the total nr. of entries, should equal
876                 * newinfo->nentries afterwards
877                 */
878         udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
879         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
880            ebt_check_entry_size_and_hooks, newinfo,
881            &i, &j, &k, &udc_cnt);
882 
883         if (ret != 0)
884                 return ret;
885 
886         if (i != j) {
887                 BUGPRINT("nentries does not equal the nr of entries in the "
888                          "(last) chain\n");
889                 return -EINVAL;
890         }
891         if (k != newinfo->nentries) {
892                 BUGPRINT("Total nentries is wrong\n");
893                 return -EINVAL;
894         }
895 
896         /* get the location of the udc, put them in an array
897          * while we're at it, allocate the chainstack
898          */
899         if (udc_cnt) {
900                 /* this will get free'd in do_replace()/ebt_register_table()
901                  * if an error occurs
902                  */
903                 newinfo->chainstack =
904                         vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
905                 if (!newinfo->chainstack)
906                         return -ENOMEM;
907                 for_each_possible_cpu(i) {
908                         newinfo->chainstack[i] =
909                           vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
910                         if (!newinfo->chainstack[i]) {
911                                 while (i)
912                                         vfree(newinfo->chainstack[--i]);
913                                 vfree(newinfo->chainstack);
914                                 newinfo->chainstack = NULL;
915                                 return -ENOMEM;
916                         }
917                 }
918 
919                 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
920                 if (!cl_s)
921                         return -ENOMEM;
922                 i = 0; /* the i'th udc */
923                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
924                    ebt_get_udc_positions, newinfo, &i, cl_s);
925                 /* sanity check */
926                 if (i != udc_cnt) {
927                         BUGPRINT("i != udc_cnt\n");
928                         vfree(cl_s);
929                         return -EFAULT;
930                 }
931         }
932 
933         /* Check for loops */
934         for (i = 0; i < NF_BR_NUMHOOKS; i++)
935                 if (newinfo->hook_entry[i])
936                         if (check_chainloops(newinfo->hook_entry[i],
937                            cl_s, udc_cnt, i, newinfo->entries)) {
938                                 vfree(cl_s);
939                                 return -EINVAL;
940                         }
941 
942         /* we now know the following (along with E=mc²):
943          *  - the nr of entries in each chain is right
944          *  - the size of the allocated space is right
945          *  - all valid hooks have a corresponding chain
946          *  - there are no loops
947          *  - wrong data can still be on the level of a single entry
948          *  - could be there are jumps to places that are not the
949          *    beginning of a chain. This can only occur in chains that
950          *    are not accessible from any base chains, so we don't care.
951          */
952 
953         /* used to know what we need to clean up if something goes wrong */
954         i = 0;
955         ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
956            ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
957         if (ret != 0) {
958                 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
959                                   ebt_cleanup_entry, net, &i);
960         }
961         vfree(cl_s);
962         return ret;
963 }
964 
965 /* called under write_lock */
966 static void get_counters(const struct ebt_counter *oldcounters,
967                          struct ebt_counter *counters, unsigned int nentries)
968 {
969         int i, cpu;
970         struct ebt_counter *counter_base;
971 
972         /* counters of cpu 0 */
973         memcpy(counters, oldcounters,
974                sizeof(struct ebt_counter) * nentries);
975 
976         /* add other counters to those of cpu 0 */
977         for_each_possible_cpu(cpu) {
978                 if (cpu == 0)
979                         continue;
980                 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
981                 for (i = 0; i < nentries; i++) {
982                         counters[i].pcnt += counter_base[i].pcnt;
983                         counters[i].bcnt += counter_base[i].bcnt;
984                 }
985         }
986 }
987 
988 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
989                               struct ebt_table_info *newinfo)
990 {
991         int ret, i;
992         struct ebt_counter *counterstmp = NULL;
993         /* used to be able to unlock earlier */
994         struct ebt_table_info *table;
995         struct ebt_table *t;
996 
997         /* the user wants counters back
998          * the check on the size is done later, when we have the lock
999          */
1000         if (repl->num_counters) {
1001                 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1002                 counterstmp = vmalloc(size);
1003                 if (!counterstmp)
1004                         return -ENOMEM;
1005         }
1006 
1007         newinfo->chainstack = NULL;
1008         ret = ebt_verify_pointers(repl, newinfo);
1009         if (ret != 0)
1010                 goto free_counterstmp;
1011 
1012         ret = translate_table(net, repl->name, newinfo);
1013 
1014         if (ret != 0)
1015                 goto free_counterstmp;
1016 
1017         t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1018         if (!t) {
1019                 ret = -ENOENT;
1020                 goto free_iterate;
1021         }
1022 
1023         /* the table doesn't like it */
1024         if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1025                 goto free_unlock;
1026 
1027         if (repl->num_counters && repl->num_counters != t->private->nentries) {
1028                 BUGPRINT("Wrong nr. of counters requested\n");
1029                 ret = -EINVAL;
1030                 goto free_unlock;
1031         }
1032 
1033         /* we have the mutex lock, so no danger in reading this pointer */
1034         table = t->private;
1035         /* make sure the table can only be rmmod'ed if it contains no rules */
1036         if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1037                 ret = -ENOENT;
1038                 goto free_unlock;
1039         } else if (table->nentries && !newinfo->nentries)
1040                 module_put(t->me);
1041         /* we need an atomic snapshot of the counters */
1042         write_lock_bh(&t->lock);
1043         if (repl->num_counters)
1044                 get_counters(t->private->counters, counterstmp,
1045                    t->private->nentries);
1046 
1047         t->private = newinfo;
1048         write_unlock_bh(&t->lock);
1049         mutex_unlock(&ebt_mutex);
1050         /* so, a user can change the chains while having messed up her counter
1051          * allocation. Only reason why this is done is because this way the lock
1052          * is held only once, while this doesn't bring the kernel into a
1053          * dangerous state.
1054          */
1055         if (repl->num_counters &&
1056            copy_to_user(repl->counters, counterstmp,
1057            repl->num_counters * sizeof(struct ebt_counter))) {
1058                 /* Silent error, can't fail, new table is already in place */
1059                 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1060         }
1061 
1062         /* decrease module count and free resources */
1063         EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1064                           ebt_cleanup_entry, net, NULL);
1065 
1066         vfree(table->entries);
1067         if (table->chainstack) {
1068                 for_each_possible_cpu(i)
1069                         vfree(table->chainstack[i]);
1070                 vfree(table->chainstack);
1071         }
1072         vfree(table);
1073 
1074         vfree(counterstmp);
1075 
1076 #ifdef CONFIG_AUDIT
1077         if (audit_enabled) {
1078                 struct audit_buffer *ab;
1079 
1080                 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1081                                      AUDIT_NETFILTER_CFG);
1082                 if (ab) {
1083                         audit_log_format(ab, "table=%s family=%u entries=%u",
1084                                          repl->name, AF_BRIDGE, repl->nentries);
1085                         audit_log_end(ab);
1086                 }
1087         }
1088 #endif
1089         return ret;
1090 
1091 free_unlock:
1092         mutex_unlock(&ebt_mutex);
1093 free_iterate:
1094         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1095                           ebt_cleanup_entry, net, NULL);
1096 free_counterstmp:
1097         vfree(counterstmp);
1098         /* can be initialized in translate_table() */
1099         if (newinfo->chainstack) {
1100                 for_each_possible_cpu(i)
1101                         vfree(newinfo->chainstack[i]);
1102                 vfree(newinfo->chainstack);
1103         }
1104         return ret;
1105 }
1106 
1107 /* replace the table */
1108 static int do_replace(struct net *net, const void __user *user,
1109                       unsigned int len)
1110 {
1111         int ret, countersize;
1112         struct ebt_table_info *newinfo;
1113         struct ebt_replace tmp;
1114 
1115         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1116                 return -EFAULT;
1117 
1118         if (len != sizeof(tmp) + tmp.entries_size) {
1119                 BUGPRINT("Wrong len argument\n");
1120                 return -EINVAL;
1121         }
1122 
1123         if (tmp.entries_size == 0) {
1124                 BUGPRINT("Entries_size never zero\n");
1125                 return -EINVAL;
1126         }
1127         /* overflow check */
1128         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1129                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1130                 return -ENOMEM;
1131         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1132                 return -ENOMEM;
1133 
1134         tmp.name[sizeof(tmp.name) - 1] = 0;
1135 
1136         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1137         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1138         if (!newinfo)
1139                 return -ENOMEM;
1140 
1141         if (countersize)
1142                 memset(newinfo->counters, 0, countersize);
1143 
1144         newinfo->entries = vmalloc(tmp.entries_size);
1145         if (!newinfo->entries) {
1146                 ret = -ENOMEM;
1147                 goto free_newinfo;
1148         }
1149         if (copy_from_user(
1150            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1151                 BUGPRINT("Couldn't copy entries from userspace\n");
1152                 ret = -EFAULT;
1153                 goto free_entries;
1154         }
1155 
1156         ret = do_replace_finish(net, &tmp, newinfo);
1157         if (ret == 0)
1158                 return ret;
1159 free_entries:
1160         vfree(newinfo->entries);
1161 free_newinfo:
1162         vfree(newinfo);
1163         return ret;
1164 }
1165 
1166 struct ebt_table *
1167 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1168 {
1169         struct ebt_table_info *newinfo;
1170         struct ebt_table *t, *table;
1171         struct ebt_replace_kernel *repl;
1172         int ret, i, countersize;
1173         void *p;
1174 
1175         if (input_table == NULL || (repl = input_table->table) == NULL ||
1176             repl->entries == NULL || repl->entries_size == 0 ||
1177             repl->counters != NULL || input_table->private != NULL) {
1178                 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1179                 return ERR_PTR(-EINVAL);
1180         }
1181 
1182         /* Don't add one table to multiple lists. */
1183         table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1184         if (!table) {
1185                 ret = -ENOMEM;
1186                 goto out;
1187         }
1188 
1189         countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1190         newinfo = vmalloc(sizeof(*newinfo) + countersize);
1191         ret = -ENOMEM;
1192         if (!newinfo)
1193                 goto free_table;
1194 
1195         p = vmalloc(repl->entries_size);
1196         if (!p)
1197                 goto free_newinfo;
1198 
1199         memcpy(p, repl->entries, repl->entries_size);
1200         newinfo->entries = p;
1201 
1202         newinfo->entries_size = repl->entries_size;
1203         newinfo->nentries = repl->nentries;
1204 
1205         if (countersize)
1206                 memset(newinfo->counters, 0, countersize);
1207 
1208         /* fill in newinfo and parse the entries */
1209         newinfo->chainstack = NULL;
1210         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1211                 if ((repl->valid_hooks & (1 << i)) == 0)
1212                         newinfo->hook_entry[i] = NULL;
1213                 else
1214                         newinfo->hook_entry[i] = p +
1215                                 ((char *)repl->hook_entry[i] - repl->entries);
1216         }
1217         ret = translate_table(net, repl->name, newinfo);
1218         if (ret != 0) {
1219                 BUGPRINT("Translate_table failed\n");
1220                 goto free_chainstack;
1221         }
1222 
1223         if (table->check && table->check(newinfo, table->valid_hooks)) {
1224                 BUGPRINT("The table doesn't like its own initial data, lol\n");
1225                 ret = -EINVAL;
1226                 goto free_chainstack;
1227         }
1228 
1229         table->private = newinfo;
1230         rwlock_init(&table->lock);
1231         mutex_lock(&ebt_mutex);
1232         list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1233                 if (strcmp(t->name, table->name) == 0) {
1234                         ret = -EEXIST;
1235                         BUGPRINT("Table name already exists\n");
1236                         goto free_unlock;
1237                 }
1238         }
1239 
1240         /* Hold a reference count if the chains aren't empty */
1241         if (newinfo->nentries && !try_module_get(table->me)) {
1242                 ret = -ENOENT;
1243                 goto free_unlock;
1244         }
1245         list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1246         mutex_unlock(&ebt_mutex);
1247         return table;
1248 free_unlock:
1249         mutex_unlock(&ebt_mutex);
1250 free_chainstack:
1251         if (newinfo->chainstack) {
1252                 for_each_possible_cpu(i)
1253                         vfree(newinfo->chainstack[i]);
1254                 vfree(newinfo->chainstack);
1255         }
1256         vfree(newinfo->entries);
1257 free_newinfo:
1258         vfree(newinfo);
1259 free_table:
1260         kfree(table);
1261 out:
1262         return ERR_PTR(ret);
1263 }
1264 
1265 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1266 {
1267         int i;
1268 
1269         if (!table) {
1270                 BUGPRINT("Request to unregister NULL table!!!\n");
1271                 return;
1272         }
1273         mutex_lock(&ebt_mutex);
1274         list_del(&table->list);
1275         mutex_unlock(&ebt_mutex);
1276         EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1277                           ebt_cleanup_entry, net, NULL);
1278         if (table->private->nentries)
1279                 module_put(table->me);
1280         vfree(table->private->entries);
1281         if (table->private->chainstack) {
1282                 for_each_possible_cpu(i)
1283                         vfree(table->private->chainstack[i]);
1284                 vfree(table->private->chainstack);
1285         }
1286         vfree(table->private);
1287         kfree(table);
1288 }
1289 
1290 /* userspace just supplied us with counters */
1291 static int do_update_counters(struct net *net, const char *name,
1292                                 struct ebt_counter __user *counters,
1293                                 unsigned int num_counters,
1294                                 const void __user *user, unsigned int len)
1295 {
1296         int i, ret;
1297         struct ebt_counter *tmp;
1298         struct ebt_table *t;
1299 
1300         if (num_counters == 0)
1301                 return -EINVAL;
1302 
1303         tmp = vmalloc(num_counters * sizeof(*tmp));
1304         if (!tmp)
1305                 return -ENOMEM;
1306 
1307         t = find_table_lock(net, name, &ret, &ebt_mutex);
1308         if (!t)
1309                 goto free_tmp;
1310 
1311         if (num_counters != t->private->nentries) {
1312                 BUGPRINT("Wrong nr of counters\n");
1313                 ret = -EINVAL;
1314                 goto unlock_mutex;
1315         }
1316 
1317         if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1318                 ret = -EFAULT;
1319                 goto unlock_mutex;
1320         }
1321 
1322         /* we want an atomic add of the counters */
1323         write_lock_bh(&t->lock);
1324 
1325         /* we add to the counters of the first cpu */
1326         for (i = 0; i < num_counters; i++) {
1327                 t->private->counters[i].pcnt += tmp[i].pcnt;
1328                 t->private->counters[i].bcnt += tmp[i].bcnt;
1329         }
1330 
1331         write_unlock_bh(&t->lock);
1332         ret = 0;
1333 unlock_mutex:
1334         mutex_unlock(&ebt_mutex);
1335 free_tmp:
1336         vfree(tmp);
1337         return ret;
1338 }
1339 
1340 static int update_counters(struct net *net, const void __user *user,
1341                             unsigned int len)
1342 {
1343         struct ebt_replace hlp;
1344 
1345         if (copy_from_user(&hlp, user, sizeof(hlp)))
1346                 return -EFAULT;
1347 
1348         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1349                 return -EINVAL;
1350 
1351         return do_update_counters(net, hlp.name, hlp.counters,
1352                                 hlp.num_counters, user, len);
1353 }
1354 
1355 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1356                                      const char *base, char __user *ubase)
1357 {
1358         char __user *hlp = ubase + ((char *)m - base);
1359         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1360 
1361         /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1362          * long. Copy 29 bytes and fill remaining bytes with zeroes.
1363          */
1364         strlcpy(name, m->u.match->name, sizeof(name));
1365         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1366                 return -EFAULT;
1367         return 0;
1368 }
1369 
1370 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1371                                        const char *base, char __user *ubase)
1372 {
1373         char __user *hlp = ubase + ((char *)w - base);
1374         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1375 
1376         strlcpy(name, w->u.watcher->name, sizeof(name));
1377         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1378                 return -EFAULT;
1379         return 0;
1380 }
1381 
1382 static inline int ebt_make_names(struct ebt_entry *e, const char *base,
1383                                  char __user *ubase)
1384 {
1385         int ret;
1386         char __user *hlp;
1387         const struct ebt_entry_target *t;
1388         char name[EBT_FUNCTION_MAXNAMELEN] = {};
1389 
1390         if (e->bitmask == 0)
1391                 return 0;
1392 
1393         hlp = ubase + (((char *)e + e->target_offset) - base);
1394         t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1395 
1396         ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1397         if (ret != 0)
1398                 return ret;
1399         ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1400         if (ret != 0)
1401                 return ret;
1402         strlcpy(name, t->u.target->name, sizeof(name));
1403         if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1404                 return -EFAULT;
1405         return 0;
1406 }
1407 
1408 static int copy_counters_to_user(struct ebt_table *t,
1409                                  const struct ebt_counter *oldcounters,
1410                                  void __user *user, unsigned int num_counters,
1411                                  unsigned int nentries)
1412 {
1413         struct ebt_counter *counterstmp;
1414         int ret = 0;
1415 
1416         /* userspace might not need the counters */
1417         if (num_counters == 0)
1418                 return 0;
1419 
1420         if (num_counters != nentries) {
1421                 BUGPRINT("Num_counters wrong\n");
1422                 return -EINVAL;
1423         }
1424 
1425         counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1426         if (!counterstmp)
1427                 return -ENOMEM;
1428 
1429         write_lock_bh(&t->lock);
1430         get_counters(oldcounters, counterstmp, nentries);
1431         write_unlock_bh(&t->lock);
1432 
1433         if (copy_to_user(user, counterstmp,
1434            nentries * sizeof(struct ebt_counter)))
1435                 ret = -EFAULT;
1436         vfree(counterstmp);
1437         return ret;
1438 }
1439 
1440 /* called with ebt_mutex locked */
1441 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1442                                    const int *len, int cmd)
1443 {
1444         struct ebt_replace tmp;
1445         const struct ebt_counter *oldcounters;
1446         unsigned int entries_size, nentries;
1447         int ret;
1448         char *entries;
1449 
1450         if (cmd == EBT_SO_GET_ENTRIES) {
1451                 entries_size = t->private->entries_size;
1452                 nentries = t->private->nentries;
1453                 entries = t->private->entries;
1454                 oldcounters = t->private->counters;
1455         } else {
1456                 entries_size = t->table->entries_size;
1457                 nentries = t->table->nentries;
1458                 entries = t->table->entries;
1459                 oldcounters = t->table->counters;
1460         }
1461 
1462         if (copy_from_user(&tmp, user, sizeof(tmp)))
1463                 return -EFAULT;
1464 
1465         if (*len != sizeof(struct ebt_replace) + entries_size +
1466            (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1467                 return -EINVAL;
1468 
1469         if (tmp.nentries != nentries) {
1470                 BUGPRINT("Nentries wrong\n");
1471                 return -EINVAL;
1472         }
1473 
1474         if (tmp.entries_size != entries_size) {
1475                 BUGPRINT("Wrong size\n");
1476                 return -EINVAL;
1477         }
1478 
1479         ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1480                                         tmp.num_counters, nentries);
1481         if (ret)
1482                 return ret;
1483 
1484         if (copy_to_user(tmp.entries, entries, entries_size)) {
1485                 BUGPRINT("Couldn't copy entries to userspace\n");
1486                 return -EFAULT;
1487         }
1488         /* set the match/watcher/target names right */
1489         return EBT_ENTRY_ITERATE(entries, entries_size,
1490            ebt_make_names, entries, tmp.entries);
1491 }
1492 
1493 static int do_ebt_set_ctl(struct sock *sk,
1494         int cmd, void __user *user, unsigned int len)
1495 {
1496         int ret;
1497         struct net *net = sock_net(sk);
1498 
1499         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1500                 return -EPERM;
1501 
1502         switch (cmd) {
1503         case EBT_SO_SET_ENTRIES:
1504                 ret = do_replace(net, user, len);
1505                 break;
1506         case EBT_SO_SET_COUNTERS:
1507                 ret = update_counters(net, user, len);
1508                 break;
1509         default:
1510                 ret = -EINVAL;
1511         }
1512         return ret;
1513 }
1514 
1515 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1516 {
1517         int ret;
1518         struct ebt_replace tmp;
1519         struct ebt_table *t;
1520         struct net *net = sock_net(sk);
1521 
1522         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1523                 return -EPERM;
1524 
1525         if (copy_from_user(&tmp, user, sizeof(tmp)))
1526                 return -EFAULT;
1527 
1528         tmp.name[sizeof(tmp.name) - 1] = '\0';
1529 
1530         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1531         if (!t)
1532                 return ret;
1533 
1534         switch (cmd) {
1535         case EBT_SO_GET_INFO:
1536         case EBT_SO_GET_INIT_INFO:
1537                 if (*len != sizeof(struct ebt_replace)) {
1538                         ret = -EINVAL;
1539                         mutex_unlock(&ebt_mutex);
1540                         break;
1541                 }
1542                 if (cmd == EBT_SO_GET_INFO) {
1543                         tmp.nentries = t->private->nentries;
1544                         tmp.entries_size = t->private->entries_size;
1545                         tmp.valid_hooks = t->valid_hooks;
1546                 } else {
1547                         tmp.nentries = t->table->nentries;
1548                         tmp.entries_size = t->table->entries_size;
1549                         tmp.valid_hooks = t->table->valid_hooks;
1550                 }
1551                 mutex_unlock(&ebt_mutex);
1552                 if (copy_to_user(user, &tmp, *len) != 0) {
1553                         BUGPRINT("c2u Didn't work\n");
1554                         ret = -EFAULT;
1555                         break;
1556                 }
1557                 ret = 0;
1558                 break;
1559 
1560         case EBT_SO_GET_ENTRIES:
1561         case EBT_SO_GET_INIT_ENTRIES:
1562                 ret = copy_everything_to_user(t, user, len, cmd);
1563                 mutex_unlock(&ebt_mutex);
1564                 break;
1565 
1566         default:
1567                 mutex_unlock(&ebt_mutex);
1568                 ret = -EINVAL;
1569         }
1570 
1571         return ret;
1572 }
1573 
1574 #ifdef CONFIG_COMPAT
1575 /* 32 bit-userspace compatibility definitions. */
1576 struct compat_ebt_replace {
1577         char name[EBT_TABLE_MAXNAMELEN];
1578         compat_uint_t valid_hooks;
1579         compat_uint_t nentries;
1580         compat_uint_t entries_size;
1581         /* start of the chains */
1582         compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1583         /* nr of counters userspace expects back */
1584         compat_uint_t num_counters;
1585         /* where the kernel will put the old counters. */
1586         compat_uptr_t counters;
1587         compat_uptr_t entries;
1588 };
1589 
1590 /* struct ebt_entry_match, _target and _watcher have same layout */
1591 struct compat_ebt_entry_mwt {
1592         union {
1593                 char name[EBT_FUNCTION_MAXNAMELEN];
1594                 compat_uptr_t ptr;
1595         } u;
1596         compat_uint_t match_size;
1597         compat_uint_t data[0];
1598 };
1599 
1600 /* account for possible padding between match_size and ->data */
1601 static int ebt_compat_entry_padsize(void)
1602 {
1603         BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1604                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1605         return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1606                         COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1607 }
1608 
1609 static int ebt_compat_match_offset(const struct xt_match *match,
1610                                    unsigned int userlen)
1611 {
1612         /* ebt_among needs special handling. The kernel .matchsize is
1613          * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1614          * value is expected.
1615          * Example: userspace sends 4500, ebt_among.c wants 4504.
1616          */
1617         if (unlikely(match->matchsize == -1))
1618                 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1619         return xt_compat_match_offset(match);
1620 }
1621 
1622 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1623                                 unsigned int *size)
1624 {
1625         const struct xt_match *match = m->u.match;
1626         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1627         int off = ebt_compat_match_offset(match, m->match_size);
1628         compat_uint_t msize = m->match_size - off;
1629 
1630         BUG_ON(off >= m->match_size);
1631 
1632         if (copy_to_user(cm->u.name, match->name,
1633             strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1634                 return -EFAULT;
1635 
1636         if (match->compat_to_user) {
1637                 if (match->compat_to_user(cm->data, m->data))
1638                         return -EFAULT;
1639         } else if (copy_to_user(cm->data, m->data, msize))
1640                         return -EFAULT;
1641 
1642         *size -= ebt_compat_entry_padsize() + off;
1643         *dstptr = cm->data;
1644         *dstptr += msize;
1645         return 0;
1646 }
1647 
1648 static int compat_target_to_user(struct ebt_entry_target *t,
1649                                  void __user **dstptr,
1650                                  unsigned int *size)
1651 {
1652         const struct xt_target *target = t->u.target;
1653         struct compat_ebt_entry_mwt __user *cm = *dstptr;
1654         int off = xt_compat_target_offset(target);
1655         compat_uint_t tsize = t->target_size - off;
1656 
1657         BUG_ON(off >= t->target_size);
1658 
1659         if (copy_to_user(cm->u.name, target->name,
1660             strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1661                 return -EFAULT;
1662 
1663         if (target->compat_to_user) {
1664                 if (target->compat_to_user(cm->data, t->data))
1665                         return -EFAULT;
1666         } else if (copy_to_user(cm->data, t->data, tsize))
1667                 return -EFAULT;
1668 
1669         *size -= ebt_compat_entry_padsize() + off;
1670         *dstptr = cm->data;
1671         *dstptr += tsize;
1672         return 0;
1673 }
1674 
1675 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1676                                   void __user **dstptr,
1677                                   unsigned int *size)
1678 {
1679         return compat_target_to_user((struct ebt_entry_target *)w,
1680                                                         dstptr, size);
1681 }
1682 
1683 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1684                                 unsigned int *size)
1685 {
1686         struct ebt_entry_target *t;
1687         struct ebt_entry __user *ce;
1688         u32 watchers_offset, target_offset, next_offset;
1689         compat_uint_t origsize;
1690         int ret;
1691 
1692         if (e->bitmask == 0) {
1693                 if (*size < sizeof(struct ebt_entries))
1694                         return -EINVAL;
1695                 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1696                         return -EFAULT;
1697 
1698                 *dstptr += sizeof(struct ebt_entries);
1699                 *size -= sizeof(struct ebt_entries);
1700                 return 0;
1701         }
1702 
1703         if (*size < sizeof(*ce))
1704                 return -EINVAL;
1705 
1706         ce = (struct ebt_entry __user *)*dstptr;
1707         if (copy_to_user(ce, e, sizeof(*ce)))
1708                 return -EFAULT;
1709 
1710         origsize = *size;
1711         *dstptr += sizeof(*ce);
1712 
1713         ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1714         if (ret)
1715                 return ret;
1716         watchers_offset = e->watchers_offset - (origsize - *size);
1717 
1718         ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1719         if (ret)
1720                 return ret;
1721         target_offset = e->target_offset - (origsize - *size);
1722 
1723         t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1724 
1725         ret = compat_target_to_user(t, dstptr, size);
1726         if (ret)
1727                 return ret;
1728         next_offset = e->next_offset - (origsize - *size);
1729 
1730         if (put_user(watchers_offset, &ce->watchers_offset) ||
1731             put_user(target_offset, &ce->target_offset) ||
1732             put_user(next_offset, &ce->next_offset))
1733                 return -EFAULT;
1734 
1735         *size -= sizeof(*ce);
1736         return 0;
1737 }
1738 
1739 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1740 {
1741         *off += ebt_compat_match_offset(m->u.match, m->match_size);
1742         *off += ebt_compat_entry_padsize();
1743         return 0;
1744 }
1745 
1746 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1747 {
1748         *off += xt_compat_target_offset(w->u.watcher);
1749         *off += ebt_compat_entry_padsize();
1750         return 0;
1751 }
1752 
1753 static int compat_calc_entry(const struct ebt_entry *e,
1754                              const struct ebt_table_info *info,
1755                              const void *base,
1756                              struct compat_ebt_replace *newinfo)
1757 {
1758         const struct ebt_entry_target *t;
1759         unsigned int entry_offset;
1760         int off, ret, i;
1761 
1762         if (e->bitmask == 0)
1763                 return 0;
1764 
1765         off = 0;
1766         entry_offset = (void *)e - base;
1767 
1768         EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1769         EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1770 
1771         t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1772 
1773         off += xt_compat_target_offset(t->u.target);
1774         off += ebt_compat_entry_padsize();
1775 
1776         newinfo->entries_size -= off;
1777 
1778         ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1779         if (ret)
1780                 return ret;
1781 
1782         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1783                 const void *hookptr = info->hook_entry[i];
1784                 if (info->hook_entry[i] &&
1785                     (e < (struct ebt_entry *)(base - hookptr))) {
1786                         newinfo->hook_entry[i] -= off;
1787                         pr_debug("0x%08X -> 0x%08X\n",
1788                                         newinfo->hook_entry[i] + off,
1789                                         newinfo->hook_entry[i]);
1790                 }
1791         }
1792 
1793         return 0;
1794 }
1795 
1796 
1797 static int compat_table_info(const struct ebt_table_info *info,
1798                              struct compat_ebt_replace *newinfo)
1799 {
1800         unsigned int size = info->entries_size;
1801         const void *entries = info->entries;
1802 
1803         newinfo->entries_size = size;
1804 
1805         xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1806         return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1807                                                         entries, newinfo);
1808 }
1809 
1810 static int compat_copy_everything_to_user(struct ebt_table *t,
1811                                           void __user *user, int *len, int cmd)
1812 {
1813         struct compat_ebt_replace repl, tmp;
1814         struct ebt_counter *oldcounters;
1815         struct ebt_table_info tinfo;
1816         int ret;
1817         void __user *pos;
1818 
1819         memset(&tinfo, 0, sizeof(tinfo));
1820 
1821         if (cmd == EBT_SO_GET_ENTRIES) {
1822                 tinfo.entries_size = t->private->entries_size;
1823                 tinfo.nentries = t->private->nentries;
1824                 tinfo.entries = t->private->entries;
1825                 oldcounters = t->private->counters;
1826         } else {
1827                 tinfo.entries_size = t->table->entries_size;
1828                 tinfo.nentries = t->table->nentries;
1829                 tinfo.entries = t->table->entries;
1830                 oldcounters = t->table->counters;
1831         }
1832 
1833         if (copy_from_user(&tmp, user, sizeof(tmp)))
1834                 return -EFAULT;
1835 
1836         if (tmp.nentries != tinfo.nentries ||
1837            (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1838                 return -EINVAL;
1839 
1840         memcpy(&repl, &tmp, sizeof(repl));
1841         if (cmd == EBT_SO_GET_ENTRIES)
1842                 ret = compat_table_info(t->private, &repl);
1843         else
1844                 ret = compat_table_info(&tinfo, &repl);
1845         if (ret)
1846                 return ret;
1847 
1848         if (*len != sizeof(tmp) + repl.entries_size +
1849            (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1850                 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1851                                 *len, tinfo.entries_size, repl.entries_size);
1852                 return -EINVAL;
1853         }
1854 
1855         /* userspace might not need the counters */
1856         ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1857                                         tmp.num_counters, tinfo.nentries);
1858         if (ret)
1859                 return ret;
1860 
1861         pos = compat_ptr(tmp.entries);
1862         return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1863                         compat_copy_entry_to_user, &pos, &tmp.entries_size);
1864 }
1865 
1866 struct ebt_entries_buf_state {
1867         char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1868         u32 buf_kern_len;       /* total size of kernel buffer */
1869         u32 buf_kern_offset;    /* amount of data copied so far */
1870         u32 buf_user_offset;    /* read position in userspace buffer */
1871 };
1872 
1873 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1874 {
1875         state->buf_kern_offset += sz;
1876         return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1877 }
1878 
1879 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1880                        void *data, unsigned int sz)
1881 {
1882         if (state->buf_kern_start == NULL)
1883                 goto count_only;
1884 
1885         BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1886 
1887         memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1888 
1889  count_only:
1890         state->buf_user_offset += sz;
1891         return ebt_buf_count(state, sz);
1892 }
1893 
1894 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1895 {
1896         char *b = state->buf_kern_start;
1897 
1898         BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1899 
1900         if (b != NULL && sz > 0)
1901                 memset(b + state->buf_kern_offset, 0, sz);
1902         /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1903         return ebt_buf_count(state, sz);
1904 }
1905 
1906 enum compat_mwt {
1907         EBT_COMPAT_MATCH,
1908         EBT_COMPAT_WATCHER,
1909         EBT_COMPAT_TARGET,
1910 };
1911 
1912 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1913                                 enum compat_mwt compat_mwt,
1914                                 struct ebt_entries_buf_state *state,
1915                                 const unsigned char *base)
1916 {
1917         char name[EBT_FUNCTION_MAXNAMELEN];
1918         struct xt_match *match;
1919         struct xt_target *wt;
1920         void *dst = NULL;
1921         int off, pad = 0;
1922         unsigned int size_kern, match_size = mwt->match_size;
1923 
1924         strlcpy(name, mwt->u.name, sizeof(name));
1925 
1926         if (state->buf_kern_start)
1927                 dst = state->buf_kern_start + state->buf_kern_offset;
1928 
1929         switch (compat_mwt) {
1930         case EBT_COMPAT_MATCH:
1931                 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1932                 if (IS_ERR(match))
1933                         return PTR_ERR(match);
1934 
1935                 off = ebt_compat_match_offset(match, match_size);
1936                 if (dst) {
1937                         if (match->compat_from_user)
1938                                 match->compat_from_user(dst, mwt->data);
1939                         else
1940                                 memcpy(dst, mwt->data, match_size);
1941                 }
1942 
1943                 size_kern = match->matchsize;
1944                 if (unlikely(size_kern == -1))
1945                         size_kern = match_size;
1946                 module_put(match->me);
1947                 break;
1948         case EBT_COMPAT_WATCHER: /* fallthrough */
1949         case EBT_COMPAT_TARGET:
1950                 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1951                 if (IS_ERR(wt))
1952                         return PTR_ERR(wt);
1953                 off = xt_compat_target_offset(wt);
1954 
1955                 if (dst) {
1956                         if (wt->compat_from_user)
1957                                 wt->compat_from_user(dst, mwt->data);
1958                         else
1959                                 memcpy(dst, mwt->data, match_size);
1960                 }
1961 
1962                 size_kern = wt->targetsize;
1963                 module_put(wt->me);
1964                 break;
1965 
1966         default:
1967                 return -EINVAL;
1968         }
1969 
1970         state->buf_kern_offset += match_size + off;
1971         state->buf_user_offset += match_size;
1972         pad = XT_ALIGN(size_kern) - size_kern;
1973 
1974         if (pad > 0 && dst) {
1975                 BUG_ON(state->buf_kern_len <= pad);
1976                 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1977                 memset(dst + size_kern, 0, pad);
1978         }
1979         return off + match_size;
1980 }
1981 
1982 /* return size of all matches, watchers or target, including necessary
1983  * alignment and padding.
1984  */
1985 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1986                         unsigned int size_left, enum compat_mwt type,
1987                         struct ebt_entries_buf_state *state, const void *base)
1988 {
1989         int growth = 0;
1990         char *buf;
1991 
1992         if (size_left == 0)
1993                 return 0;
1994 
1995         buf = (char *) match32;
1996 
1997         while (size_left >= sizeof(*match32)) {
1998                 struct ebt_entry_match *match_kern;
1999                 int ret;
2000 
2001                 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2002                 if (match_kern) {
2003                         char *tmp;
2004                         tmp = state->buf_kern_start + state->buf_kern_offset;
2005                         match_kern = (struct ebt_entry_match *) tmp;
2006                 }
2007                 ret = ebt_buf_add(state, buf, sizeof(*match32));
2008                 if (ret < 0)
2009                         return ret;
2010                 size_left -= sizeof(*match32);
2011 
2012                 /* add padding before match->data (if any) */
2013                 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2014                 if (ret < 0)
2015                         return ret;
2016 
2017                 if (match32->match_size > size_left)
2018                         return -EINVAL;
2019 
2020                 size_left -= match32->match_size;
2021 
2022                 ret = compat_mtw_from_user(match32, type, state, base);
2023                 if (ret < 0)
2024                         return ret;
2025 
2026                 BUG_ON(ret < match32->match_size);
2027                 growth += ret - match32->match_size;
2028                 growth += ebt_compat_entry_padsize();
2029 
2030                 buf += sizeof(*match32);
2031                 buf += match32->match_size;
2032 
2033                 if (match_kern)
2034                         match_kern->match_size = ret;
2035 
2036                 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2037                 match32 = (struct compat_ebt_entry_mwt *) buf;
2038         }
2039 
2040         return growth;
2041 }
2042 
2043 /* called for all ebt_entry structures. */
2044 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2045                           unsigned int *total,
2046                           struct ebt_entries_buf_state *state)
2047 {
2048         unsigned int i, j, startoff, new_offset = 0;
2049         /* stores match/watchers/targets & offset of next struct ebt_entry: */
2050         unsigned int offsets[4];
2051         unsigned int *offsets_update = NULL;
2052         int ret;
2053         char *buf_start;
2054 
2055         if (*total < sizeof(struct ebt_entries))
2056                 return -EINVAL;
2057 
2058         if (!entry->bitmask) {
2059                 *total -= sizeof(struct ebt_entries);
2060                 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2061         }
2062         if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2063                 return -EINVAL;
2064 
2065         startoff = state->buf_user_offset;
2066         /* pull in most part of ebt_entry, it does not need to be changed. */
2067         ret = ebt_buf_add(state, entry,
2068                         offsetof(struct ebt_entry, watchers_offset));
2069         if (ret < 0)
2070                 return ret;
2071 
2072         offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2073         memcpy(&offsets[1], &entry->watchers_offset,
2074                         sizeof(offsets) - sizeof(offsets[0]));
2075 
2076         if (state->buf_kern_start) {
2077                 buf_start = state->buf_kern_start + state->buf_kern_offset;
2078                 offsets_update = (unsigned int *) buf_start;
2079         }
2080         ret = ebt_buf_add(state, &offsets[1],
2081                         sizeof(offsets) - sizeof(offsets[0]));
2082         if (ret < 0)
2083                 return ret;
2084         buf_start = (char *) entry;
2085         /* 0: matches offset, always follows ebt_entry.
2086          * 1: watchers offset, from ebt_entry structure
2087          * 2: target offset, from ebt_entry structure
2088          * 3: next ebt_entry offset, from ebt_entry structure
2089          *
2090          * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2091          */
2092         for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2093                 struct compat_ebt_entry_mwt *match32;
2094                 unsigned int size;
2095                 char *buf = buf_start;
2096 
2097                 buf = buf_start + offsets[i];
2098                 if (offsets[i] > offsets[j])
2099                         return -EINVAL;
2100 
2101                 match32 = (struct compat_ebt_entry_mwt *) buf;
2102                 size = offsets[j] - offsets[i];
2103                 ret = ebt_size_mwt(match32, size, i, state, base);
2104                 if (ret < 0)
2105                         return ret;
2106                 new_offset += ret;
2107                 if (offsets_update && new_offset) {
2108                         pr_debug("change offset %d to %d\n",
2109                                 offsets_update[i], offsets[j] + new_offset);
2110                         offsets_update[i] = offsets[j] + new_offset;
2111                 }
2112         }
2113 
2114         if (state->buf_kern_start == NULL) {
2115                 unsigned int offset = buf_start - (char *) base;
2116 
2117                 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2118                 if (ret < 0)
2119                         return ret;
2120         }
2121 
2122         startoff = state->buf_user_offset - startoff;
2123 
2124         BUG_ON(*total < startoff);
2125         *total -= startoff;
2126         return 0;
2127 }
2128 
2129 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2130  * It might need more memory when copied to a 64 bit kernel in case
2131  * userspace is 32-bit. So, first task: find out how much memory is needed.
2132  *
2133  * Called before validation is performed.
2134  */
2135 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2136                                 struct ebt_entries_buf_state *state)
2137 {
2138         unsigned int size_remaining = size_user;
2139         int ret;
2140 
2141         ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2142                                         &size_remaining, state);
2143         if (ret < 0)
2144                 return ret;
2145 
2146         WARN_ON(size_remaining);
2147         return state->buf_kern_offset;
2148 }
2149 
2150 
2151 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2152                                             void __user *user, unsigned int len)
2153 {
2154         struct compat_ebt_replace tmp;
2155         int i;
2156 
2157         if (len < sizeof(tmp))
2158                 return -EINVAL;
2159 
2160         if (copy_from_user(&tmp, user, sizeof(tmp)))
2161                 return -EFAULT;
2162 
2163         if (len != sizeof(tmp) + tmp.entries_size)
2164                 return -EINVAL;
2165 
2166         if (tmp.entries_size == 0)
2167                 return -EINVAL;
2168 
2169         if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2170                         NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2171                 return -ENOMEM;
2172         if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2173                 return -ENOMEM;
2174 
2175         memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2176 
2177         /* starting with hook_entry, 32 vs. 64 bit structures are different */
2178         for (i = 0; i < NF_BR_NUMHOOKS; i++)
2179                 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2180 
2181         repl->num_counters = tmp.num_counters;
2182         repl->counters = compat_ptr(tmp.counters);
2183         repl->entries = compat_ptr(tmp.entries);
2184         return 0;
2185 }
2186 
2187 static int compat_do_replace(struct net *net, void __user *user,
2188                              unsigned int len)
2189 {
2190         int ret, i, countersize, size64;
2191         struct ebt_table_info *newinfo;
2192         struct ebt_replace tmp;
2193         struct ebt_entries_buf_state state;
2194         void *entries_tmp;
2195 
2196         ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2197         if (ret) {
2198                 /* try real handler in case userland supplied needed padding */
2199                 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2200                         ret = 0;
2201                 return ret;
2202         }
2203 
2204         countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2205         newinfo = vmalloc(sizeof(*newinfo) + countersize);
2206         if (!newinfo)
2207                 return -ENOMEM;
2208 
2209         if (countersize)
2210                 memset(newinfo->counters, 0, countersize);
2211 
2212         memset(&state, 0, sizeof(state));
2213 
2214         newinfo->entries = vmalloc(tmp.entries_size);
2215         if (!newinfo->entries) {
2216                 ret = -ENOMEM;
2217                 goto free_newinfo;
2218         }
2219         if (copy_from_user(
2220            newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2221                 ret = -EFAULT;
2222                 goto free_entries;
2223         }
2224 
2225         entries_tmp = newinfo->entries;
2226 
2227         xt_compat_lock(NFPROTO_BRIDGE);
2228 
2229         xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2230         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2231         if (ret < 0)
2232                 goto out_unlock;
2233 
2234         pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2235                 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2236                 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2237 
2238         size64 = ret;
2239         newinfo->entries = vmalloc(size64);
2240         if (!newinfo->entries) {
2241                 vfree(entries_tmp);
2242                 ret = -ENOMEM;
2243                 goto out_unlock;
2244         }
2245 
2246         memset(&state, 0, sizeof(state));
2247         state.buf_kern_start = newinfo->entries;
2248         state.buf_kern_len = size64;
2249 
2250         ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2251         BUG_ON(ret < 0);        /* parses same data again */
2252 
2253         vfree(entries_tmp);
2254         tmp.entries_size = size64;
2255 
2256         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2257                 char __user *usrptr;
2258                 if (tmp.hook_entry[i]) {
2259                         unsigned int delta;
2260                         usrptr = (char __user *) tmp.hook_entry[i];
2261                         delta = usrptr - tmp.entries;
2262                         usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2263                         tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2264                 }
2265         }
2266 
2267         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2268         xt_compat_unlock(NFPROTO_BRIDGE);
2269 
2270         ret = do_replace_finish(net, &tmp, newinfo);
2271         if (ret == 0)
2272                 return ret;
2273 free_entries:
2274         vfree(newinfo->entries);
2275 free_newinfo:
2276         vfree(newinfo);
2277         return ret;
2278 out_unlock:
2279         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2280         xt_compat_unlock(NFPROTO_BRIDGE);
2281         goto free_entries;
2282 }
2283 
2284 static int compat_update_counters(struct net *net, void __user *user,
2285                                   unsigned int len)
2286 {
2287         struct compat_ebt_replace hlp;
2288 
2289         if (copy_from_user(&hlp, user, sizeof(hlp)))
2290                 return -EFAULT;
2291 
2292         /* try real handler in case userland supplied needed padding */
2293         if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2294                 return update_counters(net, user, len);
2295 
2296         return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2297                                         hlp.num_counters, user, len);
2298 }
2299 
2300 static int compat_do_ebt_set_ctl(struct sock *sk,
2301                 int cmd, void __user *user, unsigned int len)
2302 {
2303         int ret;
2304         struct net *net = sock_net(sk);
2305 
2306         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2307                 return -EPERM;
2308 
2309         switch (cmd) {
2310         case EBT_SO_SET_ENTRIES:
2311                 ret = compat_do_replace(net, user, len);
2312                 break;
2313         case EBT_SO_SET_COUNTERS:
2314                 ret = compat_update_counters(net, user, len);
2315                 break;
2316         default:
2317                 ret = -EINVAL;
2318         }
2319         return ret;
2320 }
2321 
2322 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2323                 void __user *user, int *len)
2324 {
2325         int ret;
2326         struct compat_ebt_replace tmp;
2327         struct ebt_table *t;
2328         struct net *net = sock_net(sk);
2329 
2330         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2331                 return -EPERM;
2332 
2333         /* try real handler in case userland supplied needed padding */
2334         if ((cmd == EBT_SO_GET_INFO ||
2335              cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2336                         return do_ebt_get_ctl(sk, cmd, user, len);
2337 
2338         if (copy_from_user(&tmp, user, sizeof(tmp)))
2339                 return -EFAULT;
2340 
2341         tmp.name[sizeof(tmp.name) - 1] = '\0';
2342 
2343         t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2344         if (!t)
2345                 return ret;
2346 
2347         xt_compat_lock(NFPROTO_BRIDGE);
2348         switch (cmd) {
2349         case EBT_SO_GET_INFO:
2350                 tmp.nentries = t->private->nentries;
2351                 ret = compat_table_info(t->private, &tmp);
2352                 if (ret)
2353                         goto out;
2354                 tmp.valid_hooks = t->valid_hooks;
2355 
2356                 if (copy_to_user(user, &tmp, *len) != 0) {
2357                         ret = -EFAULT;
2358                         break;
2359                 }
2360                 ret = 0;
2361                 break;
2362         case EBT_SO_GET_INIT_INFO:
2363                 tmp.nentries = t->table->nentries;
2364                 tmp.entries_size = t->table->entries_size;
2365                 tmp.valid_hooks = t->table->valid_hooks;
2366 
2367                 if (copy_to_user(user, &tmp, *len) != 0) {
2368                         ret = -EFAULT;
2369                         break;
2370                 }
2371                 ret = 0;
2372                 break;
2373         case EBT_SO_GET_ENTRIES:
2374         case EBT_SO_GET_INIT_ENTRIES:
2375                 /* try real handler first in case of userland-side padding.
2376                  * in case we are dealing with an 'ordinary' 32 bit binary
2377                  * without 64bit compatibility padding, this will fail right
2378                  * after copy_from_user when the *len argument is validated.
2379                  *
2380                  * the compat_ variant needs to do one pass over the kernel
2381                  * data set to adjust for size differences before it the check.
2382                  */
2383                 if (copy_everything_to_user(t, user, len, cmd) == 0)
2384                         ret = 0;
2385                 else
2386                         ret = compat_copy_everything_to_user(t, user, len, cmd);
2387                 break;
2388         default:
2389                 ret = -EINVAL;
2390         }
2391  out:
2392         xt_compat_flush_offsets(NFPROTO_BRIDGE);
2393         xt_compat_unlock(NFPROTO_BRIDGE);
2394         mutex_unlock(&ebt_mutex);
2395         return ret;
2396 }
2397 #endif
2398 
2399 static struct nf_sockopt_ops ebt_sockopts = {
2400         .pf             = PF_INET,
2401         .set_optmin     = EBT_BASE_CTL,
2402         .set_optmax     = EBT_SO_SET_MAX + 1,
2403         .set            = do_ebt_set_ctl,
2404 #ifdef CONFIG_COMPAT
2405         .compat_set     = compat_do_ebt_set_ctl,
2406 #endif
2407         .get_optmin     = EBT_BASE_CTL,
2408         .get_optmax     = EBT_SO_GET_MAX + 1,
2409         .get            = do_ebt_get_ctl,
2410 #ifdef CONFIG_COMPAT
2411         .compat_get     = compat_do_ebt_get_ctl,
2412 #endif
2413         .owner          = THIS_MODULE,
2414 };
2415 
2416 static int __init ebtables_init(void)
2417 {
2418         int ret;
2419 
2420         ret = xt_register_target(&ebt_standard_target);
2421         if (ret < 0)
2422                 return ret;
2423         ret = nf_register_sockopt(&ebt_sockopts);
2424         if (ret < 0) {
2425                 xt_unregister_target(&ebt_standard_target);
2426                 return ret;
2427         }
2428 
2429         printk(KERN_INFO "Ebtables v2.0 registered\n");
2430         return 0;
2431 }
2432 
2433 static void __exit ebtables_fini(void)
2434 {
2435         nf_unregister_sockopt(&ebt_sockopts);
2436         xt_unregister_target(&ebt_standard_target);
2437         printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2438 }
2439 
2440 EXPORT_SYMBOL(ebt_register_table);
2441 EXPORT_SYMBOL(ebt_unregister_table);
2442 EXPORT_SYMBOL(ebt_do_table);
2443 module_init(ebtables_init);
2444 module_exit(ebtables_fini);
2445 MODULE_LICENSE("GPL");
2446 

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