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Merge remote-tracking branch 'sound-asoc/for-next'
[deliverable/linux.git] / net / bridge / netfilter / ebtables.c
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 /* process standard matches */
125 static inline int
126 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
127 const struct net_device *in, const struct net_device *out)
128 {
129 const struct ethhdr *h = eth_hdr(skb);
130 const struct net_bridge_port *p;
131 __be16 ethproto;
132
133 if (skb_vlan_tag_present(skb))
134 ethproto = htons(ETH_P_8021Q);
135 else
136 ethproto = h->h_proto;
137
138 if (e->bitmask & EBT_802_3) {
139 if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
140 return 1;
141 } else if (!(e->bitmask & EBT_NOPROTO) &&
142 NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
143 return 1;
144
145 if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
146 return 1;
147 if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
148 return 1;
149 /* rcu_read_lock()ed by nf_hook_slow */
150 if (in && (p = br_port_get_rcu(in)) != NULL &&
151 NF_INVF(e, EBT_ILOGICALIN,
152 ebt_dev_check(e->logical_in, p->br->dev)))
153 return 1;
154 if (out && (p = br_port_get_rcu(out)) != NULL &&
155 NF_INVF(e, EBT_ILOGICALOUT,
156 ebt_dev_check(e->logical_out, p->br->dev)))
157 return 1;
158
159 if (e->bitmask & EBT_SOURCEMAC) {
160 if (NF_INVF(e, EBT_ISOURCE,
161 !ether_addr_equal_masked(h->h_source, e->sourcemac,
162 e->sourcemsk)))
163 return 1;
164 }
165 if (e->bitmask & EBT_DESTMAC) {
166 if (NF_INVF(e, EBT_IDEST,
167 !ether_addr_equal_masked(h->h_dest, e->destmac,
168 e->destmsk)))
169 return 1;
170 }
171 return 0;
172 }
173
174 static inline
175 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
176 {
177 return (void *)entry + entry->next_offset;
178 }
179
180 /* Do some firewalling */
181 unsigned int ebt_do_table(struct sk_buff *skb,
182 const struct nf_hook_state *state,
183 struct ebt_table *table)
184 {
185 unsigned int hook = state->hook;
186 int i, nentries;
187 struct ebt_entry *point;
188 struct ebt_counter *counter_base, *cb_base;
189 const struct ebt_entry_target *t;
190 int verdict, sp = 0;
191 struct ebt_chainstack *cs;
192 struct ebt_entries *chaininfo;
193 const char *base;
194 const struct ebt_table_info *private;
195 struct xt_action_param acpar;
196
197 acpar.family = NFPROTO_BRIDGE;
198 acpar.net = state->net;
199 acpar.in = state->in;
200 acpar.out = state->out;
201 acpar.hotdrop = false;
202 acpar.hooknum = hook;
203
204 read_lock_bh(&table->lock);
205 private = table->private;
206 cb_base = COUNTER_BASE(private->counters, private->nentries,
207 smp_processor_id());
208 if (private->chainstack)
209 cs = private->chainstack[smp_processor_id()];
210 else
211 cs = NULL;
212 chaininfo = private->hook_entry[hook];
213 nentries = private->hook_entry[hook]->nentries;
214 point = (struct ebt_entry *)(private->hook_entry[hook]->data);
215 counter_base = cb_base + private->hook_entry[hook]->counter_offset;
216 /* base for chain jumps */
217 base = private->entries;
218 i = 0;
219 while (i < nentries) {
220 if (ebt_basic_match(point, skb, state->in, state->out))
221 goto letscontinue;
222
223 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
224 goto letscontinue;
225 if (acpar.hotdrop) {
226 read_unlock_bh(&table->lock);
227 return NF_DROP;
228 }
229
230 /* increase counter */
231 (*(counter_base + i)).pcnt++;
232 (*(counter_base + i)).bcnt += skb->len;
233
234 /* these should only watch: not modify, nor tell us
235 * what to do with the packet
236 */
237 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
238
239 t = (struct ebt_entry_target *)
240 (((char *)point) + point->target_offset);
241 /* standard target */
242 if (!t->u.target->target)
243 verdict = ((struct ebt_standard_target *)t)->verdict;
244 else {
245 acpar.target = t->u.target;
246 acpar.targinfo = t->data;
247 verdict = t->u.target->target(skb, &acpar);
248 }
249 if (verdict == EBT_ACCEPT) {
250 read_unlock_bh(&table->lock);
251 return NF_ACCEPT;
252 }
253 if (verdict == EBT_DROP) {
254 read_unlock_bh(&table->lock);
255 return NF_DROP;
256 }
257 if (verdict == EBT_RETURN) {
258 letsreturn:
259 #ifdef CONFIG_NETFILTER_DEBUG
260 if (sp == 0) {
261 BUGPRINT("RETURN on base chain");
262 /* act like this is EBT_CONTINUE */
263 goto letscontinue;
264 }
265 #endif
266 sp--;
267 /* put all the local variables right */
268 i = cs[sp].n;
269 chaininfo = cs[sp].chaininfo;
270 nentries = chaininfo->nentries;
271 point = cs[sp].e;
272 counter_base = cb_base +
273 chaininfo->counter_offset;
274 continue;
275 }
276 if (verdict == EBT_CONTINUE)
277 goto letscontinue;
278 #ifdef CONFIG_NETFILTER_DEBUG
279 if (verdict < 0) {
280 BUGPRINT("bogus standard verdict\n");
281 read_unlock_bh(&table->lock);
282 return NF_DROP;
283 }
284 #endif
285 /* jump to a udc */
286 cs[sp].n = i + 1;
287 cs[sp].chaininfo = chaininfo;
288 cs[sp].e = ebt_next_entry(point);
289 i = 0;
290 chaininfo = (struct ebt_entries *) (base + verdict);
291 #ifdef CONFIG_NETFILTER_DEBUG
292 if (chaininfo->distinguisher) {
293 BUGPRINT("jump to non-chain\n");
294 read_unlock_bh(&table->lock);
295 return NF_DROP;
296 }
297 #endif
298 nentries = chaininfo->nentries;
299 point = (struct ebt_entry *)chaininfo->data;
300 counter_base = cb_base + chaininfo->counter_offset;
301 sp++;
302 continue;
303 letscontinue:
304 point = ebt_next_entry(point);
305 i++;
306 }
307
308 /* I actually like this :) */
309 if (chaininfo->policy == EBT_RETURN)
310 goto letsreturn;
311 if (chaininfo->policy == EBT_ACCEPT) {
312 read_unlock_bh(&table->lock);
313 return NF_ACCEPT;
314 }
315 read_unlock_bh(&table->lock);
316 return NF_DROP;
317 }
318
319 /* If it succeeds, returns element and locks mutex */
320 static inline void *
321 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
322 struct mutex *mutex)
323 {
324 struct {
325 struct list_head list;
326 char name[EBT_FUNCTION_MAXNAMELEN];
327 } *e;
328
329 mutex_lock(mutex);
330 list_for_each_entry(e, head, list) {
331 if (strcmp(e->name, name) == 0)
332 return e;
333 }
334 *error = -ENOENT;
335 mutex_unlock(mutex);
336 return NULL;
337 }
338
339 static void *
340 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
341 int *error, struct mutex *mutex)
342 {
343 return try_then_request_module(
344 find_inlist_lock_noload(head, name, error, mutex),
345 "%s%s", prefix, name);
346 }
347
348 static inline struct ebt_table *
349 find_table_lock(struct net *net, const char *name, int *error,
350 struct mutex *mutex)
351 {
352 return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
353 "ebtable_", error, mutex);
354 }
355
356 static inline int
357 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
358 unsigned int *cnt)
359 {
360 const struct ebt_entry *e = par->entryinfo;
361 struct xt_match *match;
362 size_t left = ((char *)e + e->watchers_offset) - (char *)m;
363 int ret;
364
365 if (left < sizeof(struct ebt_entry_match) ||
366 left - sizeof(struct ebt_entry_match) < m->match_size)
367 return -EINVAL;
368
369 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
370 if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
371 if (!IS_ERR(match))
372 module_put(match->me);
373 request_module("ebt_%s", m->u.name);
374 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
375 }
376 if (IS_ERR(match))
377 return PTR_ERR(match);
378 m->u.match = match;
379
380 par->match = match;
381 par->matchinfo = m->data;
382 ret = xt_check_match(par, m->match_size,
383 e->ethproto, e->invflags & EBT_IPROTO);
384 if (ret < 0) {
385 module_put(match->me);
386 return ret;
387 }
388
389 (*cnt)++;
390 return 0;
391 }
392
393 static inline int
394 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
395 unsigned int *cnt)
396 {
397 const struct ebt_entry *e = par->entryinfo;
398 struct xt_target *watcher;
399 size_t left = ((char *)e + e->target_offset) - (char *)w;
400 int ret;
401
402 if (left < sizeof(struct ebt_entry_watcher) ||
403 left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
404 return -EINVAL;
405
406 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
407 if (IS_ERR(watcher))
408 return PTR_ERR(watcher);
409 w->u.watcher = watcher;
410
411 par->target = watcher;
412 par->targinfo = w->data;
413 ret = xt_check_target(par, w->watcher_size,
414 e->ethproto, e->invflags & EBT_IPROTO);
415 if (ret < 0) {
416 module_put(watcher->me);
417 return ret;
418 }
419
420 (*cnt)++;
421 return 0;
422 }
423
424 static int ebt_verify_pointers(const struct ebt_replace *repl,
425 struct ebt_table_info *newinfo)
426 {
427 unsigned int limit = repl->entries_size;
428 unsigned int valid_hooks = repl->valid_hooks;
429 unsigned int offset = 0;
430 int i;
431
432 for (i = 0; i < NF_BR_NUMHOOKS; i++)
433 newinfo->hook_entry[i] = NULL;
434
435 newinfo->entries_size = repl->entries_size;
436 newinfo->nentries = repl->nentries;
437
438 while (offset < limit) {
439 size_t left = limit - offset;
440 struct ebt_entry *e = (void *)newinfo->entries + offset;
441
442 if (left < sizeof(unsigned int))
443 break;
444
445 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
446 if ((valid_hooks & (1 << i)) == 0)
447 continue;
448 if ((char __user *)repl->hook_entry[i] ==
449 repl->entries + offset)
450 break;
451 }
452
453 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
454 if (e->bitmask != 0) {
455 /* we make userspace set this right,
456 * so there is no misunderstanding
457 */
458 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
459 "in distinguisher\n");
460 return -EINVAL;
461 }
462 if (i != NF_BR_NUMHOOKS)
463 newinfo->hook_entry[i] = (struct ebt_entries *)e;
464 if (left < sizeof(struct ebt_entries))
465 break;
466 offset += sizeof(struct ebt_entries);
467 } else {
468 if (left < sizeof(struct ebt_entry))
469 break;
470 if (left < e->next_offset)
471 break;
472 if (e->next_offset < sizeof(struct ebt_entry))
473 return -EINVAL;
474 offset += e->next_offset;
475 }
476 }
477 if (offset != limit) {
478 BUGPRINT("entries_size too small\n");
479 return -EINVAL;
480 }
481
482 /* check if all valid hooks have a chain */
483 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
484 if (!newinfo->hook_entry[i] &&
485 (valid_hooks & (1 << i))) {
486 BUGPRINT("Valid hook without chain\n");
487 return -EINVAL;
488 }
489 }
490 return 0;
491 }
492
493 /* this one is very careful, as it is the first function
494 * to parse the userspace data
495 */
496 static inline int
497 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
498 const struct ebt_table_info *newinfo,
499 unsigned int *n, unsigned int *cnt,
500 unsigned int *totalcnt, unsigned int *udc_cnt)
501 {
502 int i;
503
504 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
505 if ((void *)e == (void *)newinfo->hook_entry[i])
506 break;
507 }
508 /* beginning of a new chain
509 * if i == NF_BR_NUMHOOKS it must be a user defined chain
510 */
511 if (i != NF_BR_NUMHOOKS || !e->bitmask) {
512 /* this checks if the previous chain has as many entries
513 * as it said it has
514 */
515 if (*n != *cnt) {
516 BUGPRINT("nentries does not equal the nr of entries "
517 "in the chain\n");
518 return -EINVAL;
519 }
520 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
521 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
522 /* only RETURN from udc */
523 if (i != NF_BR_NUMHOOKS ||
524 ((struct ebt_entries *)e)->policy != EBT_RETURN) {
525 BUGPRINT("bad policy\n");
526 return -EINVAL;
527 }
528 }
529 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
530 (*udc_cnt)++;
531 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
532 BUGPRINT("counter_offset != totalcnt");
533 return -EINVAL;
534 }
535 *n = ((struct ebt_entries *)e)->nentries;
536 *cnt = 0;
537 return 0;
538 }
539 /* a plain old entry, heh */
540 if (sizeof(struct ebt_entry) > e->watchers_offset ||
541 e->watchers_offset > e->target_offset ||
542 e->target_offset >= e->next_offset) {
543 BUGPRINT("entry offsets not in right order\n");
544 return -EINVAL;
545 }
546 /* this is not checked anywhere else */
547 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
548 BUGPRINT("target size too small\n");
549 return -EINVAL;
550 }
551 (*cnt)++;
552 (*totalcnt)++;
553 return 0;
554 }
555
556 struct ebt_cl_stack {
557 struct ebt_chainstack cs;
558 int from;
559 unsigned int hookmask;
560 };
561
562 /* We need these positions to check that the jumps to a different part of the
563 * entries is a jump to the beginning of a new chain.
564 */
565 static inline int
566 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
567 unsigned int *n, struct ebt_cl_stack *udc)
568 {
569 int i;
570
571 /* we're only interested in chain starts */
572 if (e->bitmask)
573 return 0;
574 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
575 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
576 break;
577 }
578 /* only care about udc */
579 if (i != NF_BR_NUMHOOKS)
580 return 0;
581
582 udc[*n].cs.chaininfo = (struct ebt_entries *)e;
583 /* these initialisations are depended on later in check_chainloops() */
584 udc[*n].cs.n = 0;
585 udc[*n].hookmask = 0;
586
587 (*n)++;
588 return 0;
589 }
590
591 static inline int
592 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
593 {
594 struct xt_mtdtor_param par;
595
596 if (i && (*i)-- == 0)
597 return 1;
598
599 par.net = net;
600 par.match = m->u.match;
601 par.matchinfo = m->data;
602 par.family = NFPROTO_BRIDGE;
603 if (par.match->destroy != NULL)
604 par.match->destroy(&par);
605 module_put(par.match->me);
606 return 0;
607 }
608
609 static inline int
610 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
611 {
612 struct xt_tgdtor_param par;
613
614 if (i && (*i)-- == 0)
615 return 1;
616
617 par.net = net;
618 par.target = w->u.watcher;
619 par.targinfo = w->data;
620 par.family = NFPROTO_BRIDGE;
621 if (par.target->destroy != NULL)
622 par.target->destroy(&par);
623 module_put(par.target->me);
624 return 0;
625 }
626
627 static inline int
628 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
629 {
630 struct xt_tgdtor_param par;
631 struct ebt_entry_target *t;
632
633 if (e->bitmask == 0)
634 return 0;
635 /* we're done */
636 if (cnt && (*cnt)-- == 0)
637 return 1;
638 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
639 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
640 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
641
642 par.net = net;
643 par.target = t->u.target;
644 par.targinfo = t->data;
645 par.family = NFPROTO_BRIDGE;
646 if (par.target->destroy != NULL)
647 par.target->destroy(&par);
648 module_put(par.target->me);
649 return 0;
650 }
651
652 static inline int
653 ebt_check_entry(struct ebt_entry *e, struct net *net,
654 const struct ebt_table_info *newinfo,
655 const char *name, unsigned int *cnt,
656 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
657 {
658 struct ebt_entry_target *t;
659 struct xt_target *target;
660 unsigned int i, j, hook = 0, hookmask = 0;
661 size_t gap;
662 int ret;
663 struct xt_mtchk_param mtpar;
664 struct xt_tgchk_param tgpar;
665
666 /* don't mess with the struct ebt_entries */
667 if (e->bitmask == 0)
668 return 0;
669
670 if (e->bitmask & ~EBT_F_MASK) {
671 BUGPRINT("Unknown flag for bitmask\n");
672 return -EINVAL;
673 }
674 if (e->invflags & ~EBT_INV_MASK) {
675 BUGPRINT("Unknown flag for inv bitmask\n");
676 return -EINVAL;
677 }
678 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
679 BUGPRINT("NOPROTO & 802_3 not allowed\n");
680 return -EINVAL;
681 }
682 /* what hook do we belong to? */
683 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
684 if (!newinfo->hook_entry[i])
685 continue;
686 if ((char *)newinfo->hook_entry[i] < (char *)e)
687 hook = i;
688 else
689 break;
690 }
691 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
692 * a base chain
693 */
694 if (i < NF_BR_NUMHOOKS)
695 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
696 else {
697 for (i = 0; i < udc_cnt; i++)
698 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
699 break;
700 if (i == 0)
701 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
702 else
703 hookmask = cl_s[i - 1].hookmask;
704 }
705 i = 0;
706
707 mtpar.net = tgpar.net = net;
708 mtpar.table = tgpar.table = name;
709 mtpar.entryinfo = tgpar.entryinfo = e;
710 mtpar.hook_mask = tgpar.hook_mask = hookmask;
711 mtpar.family = tgpar.family = NFPROTO_BRIDGE;
712 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
713 if (ret != 0)
714 goto cleanup_matches;
715 j = 0;
716 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
717 if (ret != 0)
718 goto cleanup_watchers;
719 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
720 gap = e->next_offset - e->target_offset;
721
722 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
723 if (IS_ERR(target)) {
724 ret = PTR_ERR(target);
725 goto cleanup_watchers;
726 }
727
728 t->u.target = target;
729 if (t->u.target == &ebt_standard_target) {
730 if (gap < sizeof(struct ebt_standard_target)) {
731 BUGPRINT("Standard target size too big\n");
732 ret = -EFAULT;
733 goto cleanup_watchers;
734 }
735 if (((struct ebt_standard_target *)t)->verdict <
736 -NUM_STANDARD_TARGETS) {
737 BUGPRINT("Invalid standard target\n");
738 ret = -EFAULT;
739 goto cleanup_watchers;
740 }
741 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
742 module_put(t->u.target->me);
743 ret = -EFAULT;
744 goto cleanup_watchers;
745 }
746
747 tgpar.target = target;
748 tgpar.targinfo = t->data;
749 ret = xt_check_target(&tgpar, t->target_size,
750 e->ethproto, e->invflags & EBT_IPROTO);
751 if (ret < 0) {
752 module_put(target->me);
753 goto cleanup_watchers;
754 }
755 (*cnt)++;
756 return 0;
757 cleanup_watchers:
758 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
759 cleanup_matches:
760 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
761 return ret;
762 }
763
764 /* checks for loops and sets the hook mask for udc
765 * the hook mask for udc tells us from which base chains the udc can be
766 * accessed. This mask is a parameter to the check() functions of the extensions
767 */
768 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
769 unsigned int udc_cnt, unsigned int hooknr, char *base)
770 {
771 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
772 const struct ebt_entry *e = (struct ebt_entry *)chain->data;
773 const struct ebt_entry_target *t;
774
775 while (pos < nentries || chain_nr != -1) {
776 /* end of udc, go back one 'recursion' step */
777 if (pos == nentries) {
778 /* put back values of the time when this chain was called */
779 e = cl_s[chain_nr].cs.e;
780 if (cl_s[chain_nr].from != -1)
781 nentries =
782 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
783 else
784 nentries = chain->nentries;
785 pos = cl_s[chain_nr].cs.n;
786 /* make sure we won't see a loop that isn't one */
787 cl_s[chain_nr].cs.n = 0;
788 chain_nr = cl_s[chain_nr].from;
789 if (pos == nentries)
790 continue;
791 }
792 t = (struct ebt_entry_target *)
793 (((char *)e) + e->target_offset);
794 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
795 goto letscontinue;
796 if (e->target_offset + sizeof(struct ebt_standard_target) >
797 e->next_offset) {
798 BUGPRINT("Standard target size too big\n");
799 return -1;
800 }
801 verdict = ((struct ebt_standard_target *)t)->verdict;
802 if (verdict >= 0) { /* jump to another chain */
803 struct ebt_entries *hlp2 =
804 (struct ebt_entries *)(base + verdict);
805 for (i = 0; i < udc_cnt; i++)
806 if (hlp2 == cl_s[i].cs.chaininfo)
807 break;
808 /* bad destination or loop */
809 if (i == udc_cnt) {
810 BUGPRINT("bad destination\n");
811 return -1;
812 }
813 if (cl_s[i].cs.n) {
814 BUGPRINT("loop\n");
815 return -1;
816 }
817 if (cl_s[i].hookmask & (1 << hooknr))
818 goto letscontinue;
819 /* this can't be 0, so the loop test is correct */
820 cl_s[i].cs.n = pos + 1;
821 pos = 0;
822 cl_s[i].cs.e = ebt_next_entry(e);
823 e = (struct ebt_entry *)(hlp2->data);
824 nentries = hlp2->nentries;
825 cl_s[i].from = chain_nr;
826 chain_nr = i;
827 /* this udc is accessible from the base chain for hooknr */
828 cl_s[i].hookmask |= (1 << hooknr);
829 continue;
830 }
831 letscontinue:
832 e = ebt_next_entry(e);
833 pos++;
834 }
835 return 0;
836 }
837
838 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
839 static int translate_table(struct net *net, const char *name,
840 struct ebt_table_info *newinfo)
841 {
842 unsigned int i, j, k, udc_cnt;
843 int ret;
844 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
845
846 i = 0;
847 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
848 i++;
849 if (i == NF_BR_NUMHOOKS) {
850 BUGPRINT("No valid hooks specified\n");
851 return -EINVAL;
852 }
853 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
854 BUGPRINT("Chains don't start at beginning\n");
855 return -EINVAL;
856 }
857 /* make sure chains are ordered after each other in same order
858 * as their corresponding hooks
859 */
860 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
861 if (!newinfo->hook_entry[j])
862 continue;
863 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
864 BUGPRINT("Hook order must be followed\n");
865 return -EINVAL;
866 }
867 i = j;
868 }
869
870 /* do some early checkings and initialize some things */
871 i = 0; /* holds the expected nr. of entries for the chain */
872 j = 0; /* holds the up to now counted entries for the chain */
873 k = 0; /* holds the total nr. of entries, should equal
874 * newinfo->nentries afterwards
875 */
876 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
877 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
878 ebt_check_entry_size_and_hooks, newinfo,
879 &i, &j, &k, &udc_cnt);
880
881 if (ret != 0)
882 return ret;
883
884 if (i != j) {
885 BUGPRINT("nentries does not equal the nr of entries in the "
886 "(last) chain\n");
887 return -EINVAL;
888 }
889 if (k != newinfo->nentries) {
890 BUGPRINT("Total nentries is wrong\n");
891 return -EINVAL;
892 }
893
894 /* get the location of the udc, put them in an array
895 * while we're at it, allocate the chainstack
896 */
897 if (udc_cnt) {
898 /* this will get free'd in do_replace()/ebt_register_table()
899 * if an error occurs
900 */
901 newinfo->chainstack =
902 vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
903 if (!newinfo->chainstack)
904 return -ENOMEM;
905 for_each_possible_cpu(i) {
906 newinfo->chainstack[i] =
907 vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
908 if (!newinfo->chainstack[i]) {
909 while (i)
910 vfree(newinfo->chainstack[--i]);
911 vfree(newinfo->chainstack);
912 newinfo->chainstack = NULL;
913 return -ENOMEM;
914 }
915 }
916
917 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
918 if (!cl_s)
919 return -ENOMEM;
920 i = 0; /* the i'th udc */
921 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
922 ebt_get_udc_positions, newinfo, &i, cl_s);
923 /* sanity check */
924 if (i != udc_cnt) {
925 BUGPRINT("i != udc_cnt\n");
926 vfree(cl_s);
927 return -EFAULT;
928 }
929 }
930
931 /* Check for loops */
932 for (i = 0; i < NF_BR_NUMHOOKS; i++)
933 if (newinfo->hook_entry[i])
934 if (check_chainloops(newinfo->hook_entry[i],
935 cl_s, udc_cnt, i, newinfo->entries)) {
936 vfree(cl_s);
937 return -EINVAL;
938 }
939
940 /* we now know the following (along with E=mc²):
941 * - the nr of entries in each chain is right
942 * - the size of the allocated space is right
943 * - all valid hooks have a corresponding chain
944 * - there are no loops
945 * - wrong data can still be on the level of a single entry
946 * - could be there are jumps to places that are not the
947 * beginning of a chain. This can only occur in chains that
948 * are not accessible from any base chains, so we don't care.
949 */
950
951 /* used to know what we need to clean up if something goes wrong */
952 i = 0;
953 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
954 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
955 if (ret != 0) {
956 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
957 ebt_cleanup_entry, net, &i);
958 }
959 vfree(cl_s);
960 return ret;
961 }
962
963 /* called under write_lock */
964 static void get_counters(const struct ebt_counter *oldcounters,
965 struct ebt_counter *counters, unsigned int nentries)
966 {
967 int i, cpu;
968 struct ebt_counter *counter_base;
969
970 /* counters of cpu 0 */
971 memcpy(counters, oldcounters,
972 sizeof(struct ebt_counter) * nentries);
973
974 /* add other counters to those of cpu 0 */
975 for_each_possible_cpu(cpu) {
976 if (cpu == 0)
977 continue;
978 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
979 for (i = 0; i < nentries; i++) {
980 counters[i].pcnt += counter_base[i].pcnt;
981 counters[i].bcnt += counter_base[i].bcnt;
982 }
983 }
984 }
985
986 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
987 struct ebt_table_info *newinfo)
988 {
989 int ret, i;
990 struct ebt_counter *counterstmp = NULL;
991 /* used to be able to unlock earlier */
992 struct ebt_table_info *table;
993 struct ebt_table *t;
994
995 /* the user wants counters back
996 * the check on the size is done later, when we have the lock
997 */
998 if (repl->num_counters) {
999 unsigned long size = repl->num_counters * sizeof(*counterstmp);
1000 counterstmp = vmalloc(size);
1001 if (!counterstmp)
1002 return -ENOMEM;
1003 }
1004
1005 newinfo->chainstack = NULL;
1006 ret = ebt_verify_pointers(repl, newinfo);
1007 if (ret != 0)
1008 goto free_counterstmp;
1009
1010 ret = translate_table(net, repl->name, newinfo);
1011
1012 if (ret != 0)
1013 goto free_counterstmp;
1014
1015 t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1016 if (!t) {
1017 ret = -ENOENT;
1018 goto free_iterate;
1019 }
1020
1021 /* the table doesn't like it */
1022 if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1023 goto free_unlock;
1024
1025 if (repl->num_counters && repl->num_counters != t->private->nentries) {
1026 BUGPRINT("Wrong nr. of counters requested\n");
1027 ret = -EINVAL;
1028 goto free_unlock;
1029 }
1030
1031 /* we have the mutex lock, so no danger in reading this pointer */
1032 table = t->private;
1033 /* make sure the table can only be rmmod'ed if it contains no rules */
1034 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1035 ret = -ENOENT;
1036 goto free_unlock;
1037 } else if (table->nentries && !newinfo->nentries)
1038 module_put(t->me);
1039 /* we need an atomic snapshot of the counters */
1040 write_lock_bh(&t->lock);
1041 if (repl->num_counters)
1042 get_counters(t->private->counters, counterstmp,
1043 t->private->nentries);
1044
1045 t->private = newinfo;
1046 write_unlock_bh(&t->lock);
1047 mutex_unlock(&ebt_mutex);
1048 /* so, a user can change the chains while having messed up her counter
1049 * allocation. Only reason why this is done is because this way the lock
1050 * is held only once, while this doesn't bring the kernel into a
1051 * dangerous state.
1052 */
1053 if (repl->num_counters &&
1054 copy_to_user(repl->counters, counterstmp,
1055 repl->num_counters * sizeof(struct ebt_counter))) {
1056 /* Silent error, can't fail, new table is already in place */
1057 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1058 }
1059
1060 /* decrease module count and free resources */
1061 EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1062 ebt_cleanup_entry, net, NULL);
1063
1064 vfree(table->entries);
1065 if (table->chainstack) {
1066 for_each_possible_cpu(i)
1067 vfree(table->chainstack[i]);
1068 vfree(table->chainstack);
1069 }
1070 vfree(table);
1071
1072 vfree(counterstmp);
1073
1074 #ifdef CONFIG_AUDIT
1075 if (audit_enabled) {
1076 struct audit_buffer *ab;
1077
1078 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1079 AUDIT_NETFILTER_CFG);
1080 if (ab) {
1081 audit_log_format(ab, "table=%s family=%u entries=%u",
1082 repl->name, AF_BRIDGE, repl->nentries);
1083 audit_log_end(ab);
1084 }
1085 }
1086 #endif
1087 return ret;
1088
1089 free_unlock:
1090 mutex_unlock(&ebt_mutex);
1091 free_iterate:
1092 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1093 ebt_cleanup_entry, net, NULL);
1094 free_counterstmp:
1095 vfree(counterstmp);
1096 /* can be initialized in translate_table() */
1097 if (newinfo->chainstack) {
1098 for_each_possible_cpu(i)
1099 vfree(newinfo->chainstack[i]);
1100 vfree(newinfo->chainstack);
1101 }
1102 return ret;
1103 }
1104
1105 /* replace the table */
1106 static int do_replace(struct net *net, const void __user *user,
1107 unsigned int len)
1108 {
1109 int ret, countersize;
1110 struct ebt_table_info *newinfo;
1111 struct ebt_replace tmp;
1112
1113 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1114 return -EFAULT;
1115
1116 if (len != sizeof(tmp) + tmp.entries_size) {
1117 BUGPRINT("Wrong len argument\n");
1118 return -EINVAL;
1119 }
1120
1121 if (tmp.entries_size == 0) {
1122 BUGPRINT("Entries_size never zero\n");
1123 return -EINVAL;
1124 }
1125 /* overflow check */
1126 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1127 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1128 return -ENOMEM;
1129 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1130 return -ENOMEM;
1131
1132 tmp.name[sizeof(tmp.name) - 1] = 0;
1133
1134 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1135 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1136 if (!newinfo)
1137 return -ENOMEM;
1138
1139 if (countersize)
1140 memset(newinfo->counters, 0, countersize);
1141
1142 newinfo->entries = vmalloc(tmp.entries_size);
1143 if (!newinfo->entries) {
1144 ret = -ENOMEM;
1145 goto free_newinfo;
1146 }
1147 if (copy_from_user(
1148 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1149 BUGPRINT("Couldn't copy entries from userspace\n");
1150 ret = -EFAULT;
1151 goto free_entries;
1152 }
1153
1154 ret = do_replace_finish(net, &tmp, newinfo);
1155 if (ret == 0)
1156 return ret;
1157 free_entries:
1158 vfree(newinfo->entries);
1159 free_newinfo:
1160 vfree(newinfo);
1161 return ret;
1162 }
1163
1164 struct ebt_table *
1165 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1166 {
1167 struct ebt_table_info *newinfo;
1168 struct ebt_table *t, *table;
1169 struct ebt_replace_kernel *repl;
1170 int ret, i, countersize;
1171 void *p;
1172
1173 if (input_table == NULL || (repl = input_table->table) == NULL ||
1174 repl->entries == NULL || repl->entries_size == 0 ||
1175 repl->counters != NULL || input_table->private != NULL) {
1176 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1177 return ERR_PTR(-EINVAL);
1178 }
1179
1180 /* Don't add one table to multiple lists. */
1181 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1182 if (!table) {
1183 ret = -ENOMEM;
1184 goto out;
1185 }
1186
1187 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1188 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1189 ret = -ENOMEM;
1190 if (!newinfo)
1191 goto free_table;
1192
1193 p = vmalloc(repl->entries_size);
1194 if (!p)
1195 goto free_newinfo;
1196
1197 memcpy(p, repl->entries, repl->entries_size);
1198 newinfo->entries = p;
1199
1200 newinfo->entries_size = repl->entries_size;
1201 newinfo->nentries = repl->nentries;
1202
1203 if (countersize)
1204 memset(newinfo->counters, 0, countersize);
1205
1206 /* fill in newinfo and parse the entries */
1207 newinfo->chainstack = NULL;
1208 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1209 if ((repl->valid_hooks & (1 << i)) == 0)
1210 newinfo->hook_entry[i] = NULL;
1211 else
1212 newinfo->hook_entry[i] = p +
1213 ((char *)repl->hook_entry[i] - repl->entries);
1214 }
1215 ret = translate_table(net, repl->name, newinfo);
1216 if (ret != 0) {
1217 BUGPRINT("Translate_table failed\n");
1218 goto free_chainstack;
1219 }
1220
1221 if (table->check && table->check(newinfo, table->valid_hooks)) {
1222 BUGPRINT("The table doesn't like its own initial data, lol\n");
1223 ret = -EINVAL;
1224 goto free_chainstack;
1225 }
1226
1227 table->private = newinfo;
1228 rwlock_init(&table->lock);
1229 mutex_lock(&ebt_mutex);
1230 list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1231 if (strcmp(t->name, table->name) == 0) {
1232 ret = -EEXIST;
1233 BUGPRINT("Table name already exists\n");
1234 goto free_unlock;
1235 }
1236 }
1237
1238 /* Hold a reference count if the chains aren't empty */
1239 if (newinfo->nentries && !try_module_get(table->me)) {
1240 ret = -ENOENT;
1241 goto free_unlock;
1242 }
1243 list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1244 mutex_unlock(&ebt_mutex);
1245 return table;
1246 free_unlock:
1247 mutex_unlock(&ebt_mutex);
1248 free_chainstack:
1249 if (newinfo->chainstack) {
1250 for_each_possible_cpu(i)
1251 vfree(newinfo->chainstack[i]);
1252 vfree(newinfo->chainstack);
1253 }
1254 vfree(newinfo->entries);
1255 free_newinfo:
1256 vfree(newinfo);
1257 free_table:
1258 kfree(table);
1259 out:
1260 return ERR_PTR(ret);
1261 }
1262
1263 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1264 {
1265 int i;
1266
1267 if (!table) {
1268 BUGPRINT("Request to unregister NULL table!!!\n");
1269 return;
1270 }
1271 mutex_lock(&ebt_mutex);
1272 list_del(&table->list);
1273 mutex_unlock(&ebt_mutex);
1274 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1275 ebt_cleanup_entry, net, NULL);
1276 if (table->private->nentries)
1277 module_put(table->me);
1278 vfree(table->private->entries);
1279 if (table->private->chainstack) {
1280 for_each_possible_cpu(i)
1281 vfree(table->private->chainstack[i]);
1282 vfree(table->private->chainstack);
1283 }
1284 vfree(table->private);
1285 kfree(table);
1286 }
1287
1288 /* userspace just supplied us with counters */
1289 static int do_update_counters(struct net *net, const char *name,
1290 struct ebt_counter __user *counters,
1291 unsigned int num_counters,
1292 const void __user *user, unsigned int len)
1293 {
1294 int i, ret;
1295 struct ebt_counter *tmp;
1296 struct ebt_table *t;
1297
1298 if (num_counters == 0)
1299 return -EINVAL;
1300
1301 tmp = vmalloc(num_counters * sizeof(*tmp));
1302 if (!tmp)
1303 return -ENOMEM;
1304
1305 t = find_table_lock(net, name, &ret, &ebt_mutex);
1306 if (!t)
1307 goto free_tmp;
1308
1309 if (num_counters != t->private->nentries) {
1310 BUGPRINT("Wrong nr of counters\n");
1311 ret = -EINVAL;
1312 goto unlock_mutex;
1313 }
1314
1315 if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1316 ret = -EFAULT;
1317 goto unlock_mutex;
1318 }
1319
1320 /* we want an atomic add of the counters */
1321 write_lock_bh(&t->lock);
1322
1323 /* we add to the counters of the first cpu */
1324 for (i = 0; i < num_counters; i++) {
1325 t->private->counters[i].pcnt += tmp[i].pcnt;
1326 t->private->counters[i].bcnt += tmp[i].bcnt;
1327 }
1328
1329 write_unlock_bh(&t->lock);
1330 ret = 0;
1331 unlock_mutex:
1332 mutex_unlock(&ebt_mutex);
1333 free_tmp:
1334 vfree(tmp);
1335 return ret;
1336 }
1337
1338 static int update_counters(struct net *net, const void __user *user,
1339 unsigned int len)
1340 {
1341 struct ebt_replace hlp;
1342
1343 if (copy_from_user(&hlp, user, sizeof(hlp)))
1344 return -EFAULT;
1345
1346 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1347 return -EINVAL;
1348
1349 return do_update_counters(net, hlp.name, hlp.counters,
1350 hlp.num_counters, user, len);
1351 }
1352
1353 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1354 const char *base, char __user *ubase)
1355 {
1356 char __user *hlp = ubase + ((char *)m - base);
1357 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1358
1359 /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1360 * long. Copy 29 bytes and fill remaining bytes with zeroes.
1361 */
1362 strlcpy(name, m->u.match->name, sizeof(name));
1363 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1364 return -EFAULT;
1365 return 0;
1366 }
1367
1368 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1369 const char *base, char __user *ubase)
1370 {
1371 char __user *hlp = ubase + ((char *)w - base);
1372 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1373
1374 strlcpy(name, w->u.watcher->name, sizeof(name));
1375 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1376 return -EFAULT;
1377 return 0;
1378 }
1379
1380 static inline int ebt_make_names(struct ebt_entry *e, const char *base,
1381 char __user *ubase)
1382 {
1383 int ret;
1384 char __user *hlp;
1385 const struct ebt_entry_target *t;
1386 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1387
1388 if (e->bitmask == 0)
1389 return 0;
1390
1391 hlp = ubase + (((char *)e + e->target_offset) - base);
1392 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1393
1394 ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1395 if (ret != 0)
1396 return ret;
1397 ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1398 if (ret != 0)
1399 return ret;
1400 strlcpy(name, t->u.target->name, sizeof(name));
1401 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1402 return -EFAULT;
1403 return 0;
1404 }
1405
1406 static int copy_counters_to_user(struct ebt_table *t,
1407 const struct ebt_counter *oldcounters,
1408 void __user *user, unsigned int num_counters,
1409 unsigned int nentries)
1410 {
1411 struct ebt_counter *counterstmp;
1412 int ret = 0;
1413
1414 /* userspace might not need the counters */
1415 if (num_counters == 0)
1416 return 0;
1417
1418 if (num_counters != nentries) {
1419 BUGPRINT("Num_counters wrong\n");
1420 return -EINVAL;
1421 }
1422
1423 counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1424 if (!counterstmp)
1425 return -ENOMEM;
1426
1427 write_lock_bh(&t->lock);
1428 get_counters(oldcounters, counterstmp, nentries);
1429 write_unlock_bh(&t->lock);
1430
1431 if (copy_to_user(user, counterstmp,
1432 nentries * sizeof(struct ebt_counter)))
1433 ret = -EFAULT;
1434 vfree(counterstmp);
1435 return ret;
1436 }
1437
1438 /* called with ebt_mutex locked */
1439 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1440 const int *len, int cmd)
1441 {
1442 struct ebt_replace tmp;
1443 const struct ebt_counter *oldcounters;
1444 unsigned int entries_size, nentries;
1445 int ret;
1446 char *entries;
1447
1448 if (cmd == EBT_SO_GET_ENTRIES) {
1449 entries_size = t->private->entries_size;
1450 nentries = t->private->nentries;
1451 entries = t->private->entries;
1452 oldcounters = t->private->counters;
1453 } else {
1454 entries_size = t->table->entries_size;
1455 nentries = t->table->nentries;
1456 entries = t->table->entries;
1457 oldcounters = t->table->counters;
1458 }
1459
1460 if (copy_from_user(&tmp, user, sizeof(tmp)))
1461 return -EFAULT;
1462
1463 if (*len != sizeof(struct ebt_replace) + entries_size +
1464 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1465 return -EINVAL;
1466
1467 if (tmp.nentries != nentries) {
1468 BUGPRINT("Nentries wrong\n");
1469 return -EINVAL;
1470 }
1471
1472 if (tmp.entries_size != entries_size) {
1473 BUGPRINT("Wrong size\n");
1474 return -EINVAL;
1475 }
1476
1477 ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1478 tmp.num_counters, nentries);
1479 if (ret)
1480 return ret;
1481
1482 if (copy_to_user(tmp.entries, entries, entries_size)) {
1483 BUGPRINT("Couldn't copy entries to userspace\n");
1484 return -EFAULT;
1485 }
1486 /* set the match/watcher/target names right */
1487 return EBT_ENTRY_ITERATE(entries, entries_size,
1488 ebt_make_names, entries, tmp.entries);
1489 }
1490
1491 static int do_ebt_set_ctl(struct sock *sk,
1492 int cmd, void __user *user, unsigned int len)
1493 {
1494 int ret;
1495 struct net *net = sock_net(sk);
1496
1497 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1498 return -EPERM;
1499
1500 switch (cmd) {
1501 case EBT_SO_SET_ENTRIES:
1502 ret = do_replace(net, user, len);
1503 break;
1504 case EBT_SO_SET_COUNTERS:
1505 ret = update_counters(net, user, len);
1506 break;
1507 default:
1508 ret = -EINVAL;
1509 }
1510 return ret;
1511 }
1512
1513 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1514 {
1515 int ret;
1516 struct ebt_replace tmp;
1517 struct ebt_table *t;
1518 struct net *net = sock_net(sk);
1519
1520 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1521 return -EPERM;
1522
1523 if (copy_from_user(&tmp, user, sizeof(tmp)))
1524 return -EFAULT;
1525
1526 tmp.name[sizeof(tmp.name) - 1] = '\0';
1527
1528 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1529 if (!t)
1530 return ret;
1531
1532 switch (cmd) {
1533 case EBT_SO_GET_INFO:
1534 case EBT_SO_GET_INIT_INFO:
1535 if (*len != sizeof(struct ebt_replace)) {
1536 ret = -EINVAL;
1537 mutex_unlock(&ebt_mutex);
1538 break;
1539 }
1540 if (cmd == EBT_SO_GET_INFO) {
1541 tmp.nentries = t->private->nentries;
1542 tmp.entries_size = t->private->entries_size;
1543 tmp.valid_hooks = t->valid_hooks;
1544 } else {
1545 tmp.nentries = t->table->nentries;
1546 tmp.entries_size = t->table->entries_size;
1547 tmp.valid_hooks = t->table->valid_hooks;
1548 }
1549 mutex_unlock(&ebt_mutex);
1550 if (copy_to_user(user, &tmp, *len) != 0) {
1551 BUGPRINT("c2u Didn't work\n");
1552 ret = -EFAULT;
1553 break;
1554 }
1555 ret = 0;
1556 break;
1557
1558 case EBT_SO_GET_ENTRIES:
1559 case EBT_SO_GET_INIT_ENTRIES:
1560 ret = copy_everything_to_user(t, user, len, cmd);
1561 mutex_unlock(&ebt_mutex);
1562 break;
1563
1564 default:
1565 mutex_unlock(&ebt_mutex);
1566 ret = -EINVAL;
1567 }
1568
1569 return ret;
1570 }
1571
1572 #ifdef CONFIG_COMPAT
1573 /* 32 bit-userspace compatibility definitions. */
1574 struct compat_ebt_replace {
1575 char name[EBT_TABLE_MAXNAMELEN];
1576 compat_uint_t valid_hooks;
1577 compat_uint_t nentries;
1578 compat_uint_t entries_size;
1579 /* start of the chains */
1580 compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1581 /* nr of counters userspace expects back */
1582 compat_uint_t num_counters;
1583 /* where the kernel will put the old counters. */
1584 compat_uptr_t counters;
1585 compat_uptr_t entries;
1586 };
1587
1588 /* struct ebt_entry_match, _target and _watcher have same layout */
1589 struct compat_ebt_entry_mwt {
1590 union {
1591 char name[EBT_FUNCTION_MAXNAMELEN];
1592 compat_uptr_t ptr;
1593 } u;
1594 compat_uint_t match_size;
1595 compat_uint_t data[0];
1596 };
1597
1598 /* account for possible padding between match_size and ->data */
1599 static int ebt_compat_entry_padsize(void)
1600 {
1601 BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1602 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1603 return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1604 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1605 }
1606
1607 static int ebt_compat_match_offset(const struct xt_match *match,
1608 unsigned int userlen)
1609 {
1610 /* ebt_among needs special handling. The kernel .matchsize is
1611 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1612 * value is expected.
1613 * Example: userspace sends 4500, ebt_among.c wants 4504.
1614 */
1615 if (unlikely(match->matchsize == -1))
1616 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1617 return xt_compat_match_offset(match);
1618 }
1619
1620 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1621 unsigned int *size)
1622 {
1623 const struct xt_match *match = m->u.match;
1624 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1625 int off = ebt_compat_match_offset(match, m->match_size);
1626 compat_uint_t msize = m->match_size - off;
1627
1628 BUG_ON(off >= m->match_size);
1629
1630 if (copy_to_user(cm->u.name, match->name,
1631 strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1632 return -EFAULT;
1633
1634 if (match->compat_to_user) {
1635 if (match->compat_to_user(cm->data, m->data))
1636 return -EFAULT;
1637 } else if (copy_to_user(cm->data, m->data, msize))
1638 return -EFAULT;
1639
1640 *size -= ebt_compat_entry_padsize() + off;
1641 *dstptr = cm->data;
1642 *dstptr += msize;
1643 return 0;
1644 }
1645
1646 static int compat_target_to_user(struct ebt_entry_target *t,
1647 void __user **dstptr,
1648 unsigned int *size)
1649 {
1650 const struct xt_target *target = t->u.target;
1651 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1652 int off = xt_compat_target_offset(target);
1653 compat_uint_t tsize = t->target_size - off;
1654
1655 BUG_ON(off >= t->target_size);
1656
1657 if (copy_to_user(cm->u.name, target->name,
1658 strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1659 return -EFAULT;
1660
1661 if (target->compat_to_user) {
1662 if (target->compat_to_user(cm->data, t->data))
1663 return -EFAULT;
1664 } else if (copy_to_user(cm->data, t->data, tsize))
1665 return -EFAULT;
1666
1667 *size -= ebt_compat_entry_padsize() + off;
1668 *dstptr = cm->data;
1669 *dstptr += tsize;
1670 return 0;
1671 }
1672
1673 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1674 void __user **dstptr,
1675 unsigned int *size)
1676 {
1677 return compat_target_to_user((struct ebt_entry_target *)w,
1678 dstptr, size);
1679 }
1680
1681 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1682 unsigned int *size)
1683 {
1684 struct ebt_entry_target *t;
1685 struct ebt_entry __user *ce;
1686 u32 watchers_offset, target_offset, next_offset;
1687 compat_uint_t origsize;
1688 int ret;
1689
1690 if (e->bitmask == 0) {
1691 if (*size < sizeof(struct ebt_entries))
1692 return -EINVAL;
1693 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1694 return -EFAULT;
1695
1696 *dstptr += sizeof(struct ebt_entries);
1697 *size -= sizeof(struct ebt_entries);
1698 return 0;
1699 }
1700
1701 if (*size < sizeof(*ce))
1702 return -EINVAL;
1703
1704 ce = (struct ebt_entry __user *)*dstptr;
1705 if (copy_to_user(ce, e, sizeof(*ce)))
1706 return -EFAULT;
1707
1708 origsize = *size;
1709 *dstptr += sizeof(*ce);
1710
1711 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1712 if (ret)
1713 return ret;
1714 watchers_offset = e->watchers_offset - (origsize - *size);
1715
1716 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1717 if (ret)
1718 return ret;
1719 target_offset = e->target_offset - (origsize - *size);
1720
1721 t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1722
1723 ret = compat_target_to_user(t, dstptr, size);
1724 if (ret)
1725 return ret;
1726 next_offset = e->next_offset - (origsize - *size);
1727
1728 if (put_user(watchers_offset, &ce->watchers_offset) ||
1729 put_user(target_offset, &ce->target_offset) ||
1730 put_user(next_offset, &ce->next_offset))
1731 return -EFAULT;
1732
1733 *size -= sizeof(*ce);
1734 return 0;
1735 }
1736
1737 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1738 {
1739 *off += ebt_compat_match_offset(m->u.match, m->match_size);
1740 *off += ebt_compat_entry_padsize();
1741 return 0;
1742 }
1743
1744 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1745 {
1746 *off += xt_compat_target_offset(w->u.watcher);
1747 *off += ebt_compat_entry_padsize();
1748 return 0;
1749 }
1750
1751 static int compat_calc_entry(const struct ebt_entry *e,
1752 const struct ebt_table_info *info,
1753 const void *base,
1754 struct compat_ebt_replace *newinfo)
1755 {
1756 const struct ebt_entry_target *t;
1757 unsigned int entry_offset;
1758 int off, ret, i;
1759
1760 if (e->bitmask == 0)
1761 return 0;
1762
1763 off = 0;
1764 entry_offset = (void *)e - base;
1765
1766 EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1767 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1768
1769 t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1770
1771 off += xt_compat_target_offset(t->u.target);
1772 off += ebt_compat_entry_padsize();
1773
1774 newinfo->entries_size -= off;
1775
1776 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1777 if (ret)
1778 return ret;
1779
1780 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1781 const void *hookptr = info->hook_entry[i];
1782 if (info->hook_entry[i] &&
1783 (e < (struct ebt_entry *)(base - hookptr))) {
1784 newinfo->hook_entry[i] -= off;
1785 pr_debug("0x%08X -> 0x%08X\n",
1786 newinfo->hook_entry[i] + off,
1787 newinfo->hook_entry[i]);
1788 }
1789 }
1790
1791 return 0;
1792 }
1793
1794
1795 static int compat_table_info(const struct ebt_table_info *info,
1796 struct compat_ebt_replace *newinfo)
1797 {
1798 unsigned int size = info->entries_size;
1799 const void *entries = info->entries;
1800
1801 newinfo->entries_size = size;
1802
1803 xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1804 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1805 entries, newinfo);
1806 }
1807
1808 static int compat_copy_everything_to_user(struct ebt_table *t,
1809 void __user *user, int *len, int cmd)
1810 {
1811 struct compat_ebt_replace repl, tmp;
1812 struct ebt_counter *oldcounters;
1813 struct ebt_table_info tinfo;
1814 int ret;
1815 void __user *pos;
1816
1817 memset(&tinfo, 0, sizeof(tinfo));
1818
1819 if (cmd == EBT_SO_GET_ENTRIES) {
1820 tinfo.entries_size = t->private->entries_size;
1821 tinfo.nentries = t->private->nentries;
1822 tinfo.entries = t->private->entries;
1823 oldcounters = t->private->counters;
1824 } else {
1825 tinfo.entries_size = t->table->entries_size;
1826 tinfo.nentries = t->table->nentries;
1827 tinfo.entries = t->table->entries;
1828 oldcounters = t->table->counters;
1829 }
1830
1831 if (copy_from_user(&tmp, user, sizeof(tmp)))
1832 return -EFAULT;
1833
1834 if (tmp.nentries != tinfo.nentries ||
1835 (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1836 return -EINVAL;
1837
1838 memcpy(&repl, &tmp, sizeof(repl));
1839 if (cmd == EBT_SO_GET_ENTRIES)
1840 ret = compat_table_info(t->private, &repl);
1841 else
1842 ret = compat_table_info(&tinfo, &repl);
1843 if (ret)
1844 return ret;
1845
1846 if (*len != sizeof(tmp) + repl.entries_size +
1847 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1848 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1849 *len, tinfo.entries_size, repl.entries_size);
1850 return -EINVAL;
1851 }
1852
1853 /* userspace might not need the counters */
1854 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1855 tmp.num_counters, tinfo.nentries);
1856 if (ret)
1857 return ret;
1858
1859 pos = compat_ptr(tmp.entries);
1860 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1861 compat_copy_entry_to_user, &pos, &tmp.entries_size);
1862 }
1863
1864 struct ebt_entries_buf_state {
1865 char *buf_kern_start; /* kernel buffer to copy (translated) data to */
1866 u32 buf_kern_len; /* total size of kernel buffer */
1867 u32 buf_kern_offset; /* amount of data copied so far */
1868 u32 buf_user_offset; /* read position in userspace buffer */
1869 };
1870
1871 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1872 {
1873 state->buf_kern_offset += sz;
1874 return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1875 }
1876
1877 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1878 void *data, unsigned int sz)
1879 {
1880 if (state->buf_kern_start == NULL)
1881 goto count_only;
1882
1883 BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1884
1885 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1886
1887 count_only:
1888 state->buf_user_offset += sz;
1889 return ebt_buf_count(state, sz);
1890 }
1891
1892 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1893 {
1894 char *b = state->buf_kern_start;
1895
1896 BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1897
1898 if (b != NULL && sz > 0)
1899 memset(b + state->buf_kern_offset, 0, sz);
1900 /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1901 return ebt_buf_count(state, sz);
1902 }
1903
1904 enum compat_mwt {
1905 EBT_COMPAT_MATCH,
1906 EBT_COMPAT_WATCHER,
1907 EBT_COMPAT_TARGET,
1908 };
1909
1910 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1911 enum compat_mwt compat_mwt,
1912 struct ebt_entries_buf_state *state,
1913 const unsigned char *base)
1914 {
1915 char name[EBT_FUNCTION_MAXNAMELEN];
1916 struct xt_match *match;
1917 struct xt_target *wt;
1918 void *dst = NULL;
1919 int off, pad = 0;
1920 unsigned int size_kern, match_size = mwt->match_size;
1921
1922 strlcpy(name, mwt->u.name, sizeof(name));
1923
1924 if (state->buf_kern_start)
1925 dst = state->buf_kern_start + state->buf_kern_offset;
1926
1927 switch (compat_mwt) {
1928 case EBT_COMPAT_MATCH:
1929 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1930 if (IS_ERR(match))
1931 return PTR_ERR(match);
1932
1933 off = ebt_compat_match_offset(match, match_size);
1934 if (dst) {
1935 if (match->compat_from_user)
1936 match->compat_from_user(dst, mwt->data);
1937 else
1938 memcpy(dst, mwt->data, match_size);
1939 }
1940
1941 size_kern = match->matchsize;
1942 if (unlikely(size_kern == -1))
1943 size_kern = match_size;
1944 module_put(match->me);
1945 break;
1946 case EBT_COMPAT_WATCHER: /* fallthrough */
1947 case EBT_COMPAT_TARGET:
1948 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1949 if (IS_ERR(wt))
1950 return PTR_ERR(wt);
1951 off = xt_compat_target_offset(wt);
1952
1953 if (dst) {
1954 if (wt->compat_from_user)
1955 wt->compat_from_user(dst, mwt->data);
1956 else
1957 memcpy(dst, mwt->data, match_size);
1958 }
1959
1960 size_kern = wt->targetsize;
1961 module_put(wt->me);
1962 break;
1963
1964 default:
1965 return -EINVAL;
1966 }
1967
1968 state->buf_kern_offset += match_size + off;
1969 state->buf_user_offset += match_size;
1970 pad = XT_ALIGN(size_kern) - size_kern;
1971
1972 if (pad > 0 && dst) {
1973 BUG_ON(state->buf_kern_len <= pad);
1974 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1975 memset(dst + size_kern, 0, pad);
1976 }
1977 return off + match_size;
1978 }
1979
1980 /* return size of all matches, watchers or target, including necessary
1981 * alignment and padding.
1982 */
1983 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1984 unsigned int size_left, enum compat_mwt type,
1985 struct ebt_entries_buf_state *state, const void *base)
1986 {
1987 int growth = 0;
1988 char *buf;
1989
1990 if (size_left == 0)
1991 return 0;
1992
1993 buf = (char *) match32;
1994
1995 while (size_left >= sizeof(*match32)) {
1996 struct ebt_entry_match *match_kern;
1997 int ret;
1998
1999 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2000 if (match_kern) {
2001 char *tmp;
2002 tmp = state->buf_kern_start + state->buf_kern_offset;
2003 match_kern = (struct ebt_entry_match *) tmp;
2004 }
2005 ret = ebt_buf_add(state, buf, sizeof(*match32));
2006 if (ret < 0)
2007 return ret;
2008 size_left -= sizeof(*match32);
2009
2010 /* add padding before match->data (if any) */
2011 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2012 if (ret < 0)
2013 return ret;
2014
2015 if (match32->match_size > size_left)
2016 return -EINVAL;
2017
2018 size_left -= match32->match_size;
2019
2020 ret = compat_mtw_from_user(match32, type, state, base);
2021 if (ret < 0)
2022 return ret;
2023
2024 BUG_ON(ret < match32->match_size);
2025 growth += ret - match32->match_size;
2026 growth += ebt_compat_entry_padsize();
2027
2028 buf += sizeof(*match32);
2029 buf += match32->match_size;
2030
2031 if (match_kern)
2032 match_kern->match_size = ret;
2033
2034 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2035 match32 = (struct compat_ebt_entry_mwt *) buf;
2036 }
2037
2038 return growth;
2039 }
2040
2041 /* called for all ebt_entry structures. */
2042 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2043 unsigned int *total,
2044 struct ebt_entries_buf_state *state)
2045 {
2046 unsigned int i, j, startoff, new_offset = 0;
2047 /* stores match/watchers/targets & offset of next struct ebt_entry: */
2048 unsigned int offsets[4];
2049 unsigned int *offsets_update = NULL;
2050 int ret;
2051 char *buf_start;
2052
2053 if (*total < sizeof(struct ebt_entries))
2054 return -EINVAL;
2055
2056 if (!entry->bitmask) {
2057 *total -= sizeof(struct ebt_entries);
2058 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2059 }
2060 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2061 return -EINVAL;
2062
2063 startoff = state->buf_user_offset;
2064 /* pull in most part of ebt_entry, it does not need to be changed. */
2065 ret = ebt_buf_add(state, entry,
2066 offsetof(struct ebt_entry, watchers_offset));
2067 if (ret < 0)
2068 return ret;
2069
2070 offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2071 memcpy(&offsets[1], &entry->watchers_offset,
2072 sizeof(offsets) - sizeof(offsets[0]));
2073
2074 if (state->buf_kern_start) {
2075 buf_start = state->buf_kern_start + state->buf_kern_offset;
2076 offsets_update = (unsigned int *) buf_start;
2077 }
2078 ret = ebt_buf_add(state, &offsets[1],
2079 sizeof(offsets) - sizeof(offsets[0]));
2080 if (ret < 0)
2081 return ret;
2082 buf_start = (char *) entry;
2083 /* 0: matches offset, always follows ebt_entry.
2084 * 1: watchers offset, from ebt_entry structure
2085 * 2: target offset, from ebt_entry structure
2086 * 3: next ebt_entry offset, from ebt_entry structure
2087 *
2088 * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2089 */
2090 for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2091 struct compat_ebt_entry_mwt *match32;
2092 unsigned int size;
2093 char *buf = buf_start;
2094
2095 buf = buf_start + offsets[i];
2096 if (offsets[i] > offsets[j])
2097 return -EINVAL;
2098
2099 match32 = (struct compat_ebt_entry_mwt *) buf;
2100 size = offsets[j] - offsets[i];
2101 ret = ebt_size_mwt(match32, size, i, state, base);
2102 if (ret < 0)
2103 return ret;
2104 new_offset += ret;
2105 if (offsets_update && new_offset) {
2106 pr_debug("change offset %d to %d\n",
2107 offsets_update[i], offsets[j] + new_offset);
2108 offsets_update[i] = offsets[j] + new_offset;
2109 }
2110 }
2111
2112 if (state->buf_kern_start == NULL) {
2113 unsigned int offset = buf_start - (char *) base;
2114
2115 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2116 if (ret < 0)
2117 return ret;
2118 }
2119
2120 startoff = state->buf_user_offset - startoff;
2121
2122 BUG_ON(*total < startoff);
2123 *total -= startoff;
2124 return 0;
2125 }
2126
2127 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2128 * It might need more memory when copied to a 64 bit kernel in case
2129 * userspace is 32-bit. So, first task: find out how much memory is needed.
2130 *
2131 * Called before validation is performed.
2132 */
2133 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2134 struct ebt_entries_buf_state *state)
2135 {
2136 unsigned int size_remaining = size_user;
2137 int ret;
2138
2139 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2140 &size_remaining, state);
2141 if (ret < 0)
2142 return ret;
2143
2144 WARN_ON(size_remaining);
2145 return state->buf_kern_offset;
2146 }
2147
2148
2149 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2150 void __user *user, unsigned int len)
2151 {
2152 struct compat_ebt_replace tmp;
2153 int i;
2154
2155 if (len < sizeof(tmp))
2156 return -EINVAL;
2157
2158 if (copy_from_user(&tmp, user, sizeof(tmp)))
2159 return -EFAULT;
2160
2161 if (len != sizeof(tmp) + tmp.entries_size)
2162 return -EINVAL;
2163
2164 if (tmp.entries_size == 0)
2165 return -EINVAL;
2166
2167 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2168 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2169 return -ENOMEM;
2170 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2171 return -ENOMEM;
2172
2173 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2174
2175 /* starting with hook_entry, 32 vs. 64 bit structures are different */
2176 for (i = 0; i < NF_BR_NUMHOOKS; i++)
2177 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2178
2179 repl->num_counters = tmp.num_counters;
2180 repl->counters = compat_ptr(tmp.counters);
2181 repl->entries = compat_ptr(tmp.entries);
2182 return 0;
2183 }
2184
2185 static int compat_do_replace(struct net *net, void __user *user,
2186 unsigned int len)
2187 {
2188 int ret, i, countersize, size64;
2189 struct ebt_table_info *newinfo;
2190 struct ebt_replace tmp;
2191 struct ebt_entries_buf_state state;
2192 void *entries_tmp;
2193
2194 ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2195 if (ret) {
2196 /* try real handler in case userland supplied needed padding */
2197 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2198 ret = 0;
2199 return ret;
2200 }
2201
2202 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2203 newinfo = vmalloc(sizeof(*newinfo) + countersize);
2204 if (!newinfo)
2205 return -ENOMEM;
2206
2207 if (countersize)
2208 memset(newinfo->counters, 0, countersize);
2209
2210 memset(&state, 0, sizeof(state));
2211
2212 newinfo->entries = vmalloc(tmp.entries_size);
2213 if (!newinfo->entries) {
2214 ret = -ENOMEM;
2215 goto free_newinfo;
2216 }
2217 if (copy_from_user(
2218 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2219 ret = -EFAULT;
2220 goto free_entries;
2221 }
2222
2223 entries_tmp = newinfo->entries;
2224
2225 xt_compat_lock(NFPROTO_BRIDGE);
2226
2227 xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2228 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2229 if (ret < 0)
2230 goto out_unlock;
2231
2232 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2233 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2234 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2235
2236 size64 = ret;
2237 newinfo->entries = vmalloc(size64);
2238 if (!newinfo->entries) {
2239 vfree(entries_tmp);
2240 ret = -ENOMEM;
2241 goto out_unlock;
2242 }
2243
2244 memset(&state, 0, sizeof(state));
2245 state.buf_kern_start = newinfo->entries;
2246 state.buf_kern_len = size64;
2247
2248 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2249 BUG_ON(ret < 0); /* parses same data again */
2250
2251 vfree(entries_tmp);
2252 tmp.entries_size = size64;
2253
2254 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2255 char __user *usrptr;
2256 if (tmp.hook_entry[i]) {
2257 unsigned int delta;
2258 usrptr = (char __user *) tmp.hook_entry[i];
2259 delta = usrptr - tmp.entries;
2260 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2261 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2262 }
2263 }
2264
2265 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2266 xt_compat_unlock(NFPROTO_BRIDGE);
2267
2268 ret = do_replace_finish(net, &tmp, newinfo);
2269 if (ret == 0)
2270 return ret;
2271 free_entries:
2272 vfree(newinfo->entries);
2273 free_newinfo:
2274 vfree(newinfo);
2275 return ret;
2276 out_unlock:
2277 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2278 xt_compat_unlock(NFPROTO_BRIDGE);
2279 goto free_entries;
2280 }
2281
2282 static int compat_update_counters(struct net *net, void __user *user,
2283 unsigned int len)
2284 {
2285 struct compat_ebt_replace hlp;
2286
2287 if (copy_from_user(&hlp, user, sizeof(hlp)))
2288 return -EFAULT;
2289
2290 /* try real handler in case userland supplied needed padding */
2291 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2292 return update_counters(net, user, len);
2293
2294 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2295 hlp.num_counters, user, len);
2296 }
2297
2298 static int compat_do_ebt_set_ctl(struct sock *sk,
2299 int cmd, void __user *user, unsigned int len)
2300 {
2301 int ret;
2302 struct net *net = sock_net(sk);
2303
2304 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2305 return -EPERM;
2306
2307 switch (cmd) {
2308 case EBT_SO_SET_ENTRIES:
2309 ret = compat_do_replace(net, user, len);
2310 break;
2311 case EBT_SO_SET_COUNTERS:
2312 ret = compat_update_counters(net, user, len);
2313 break;
2314 default:
2315 ret = -EINVAL;
2316 }
2317 return ret;
2318 }
2319
2320 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2321 void __user *user, int *len)
2322 {
2323 int ret;
2324 struct compat_ebt_replace tmp;
2325 struct ebt_table *t;
2326 struct net *net = sock_net(sk);
2327
2328 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2329 return -EPERM;
2330
2331 /* try real handler in case userland supplied needed padding */
2332 if ((cmd == EBT_SO_GET_INFO ||
2333 cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2334 return do_ebt_get_ctl(sk, cmd, user, len);
2335
2336 if (copy_from_user(&tmp, user, sizeof(tmp)))
2337 return -EFAULT;
2338
2339 tmp.name[sizeof(tmp.name) - 1] = '\0';
2340
2341 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2342 if (!t)
2343 return ret;
2344
2345 xt_compat_lock(NFPROTO_BRIDGE);
2346 switch (cmd) {
2347 case EBT_SO_GET_INFO:
2348 tmp.nentries = t->private->nentries;
2349 ret = compat_table_info(t->private, &tmp);
2350 if (ret)
2351 goto out;
2352 tmp.valid_hooks = t->valid_hooks;
2353
2354 if (copy_to_user(user, &tmp, *len) != 0) {
2355 ret = -EFAULT;
2356 break;
2357 }
2358 ret = 0;
2359 break;
2360 case EBT_SO_GET_INIT_INFO:
2361 tmp.nentries = t->table->nentries;
2362 tmp.entries_size = t->table->entries_size;
2363 tmp.valid_hooks = t->table->valid_hooks;
2364
2365 if (copy_to_user(user, &tmp, *len) != 0) {
2366 ret = -EFAULT;
2367 break;
2368 }
2369 ret = 0;
2370 break;
2371 case EBT_SO_GET_ENTRIES:
2372 case EBT_SO_GET_INIT_ENTRIES:
2373 /* try real handler first in case of userland-side padding.
2374 * in case we are dealing with an 'ordinary' 32 bit binary
2375 * without 64bit compatibility padding, this will fail right
2376 * after copy_from_user when the *len argument is validated.
2377 *
2378 * the compat_ variant needs to do one pass over the kernel
2379 * data set to adjust for size differences before it the check.
2380 */
2381 if (copy_everything_to_user(t, user, len, cmd) == 0)
2382 ret = 0;
2383 else
2384 ret = compat_copy_everything_to_user(t, user, len, cmd);
2385 break;
2386 default:
2387 ret = -EINVAL;
2388 }
2389 out:
2390 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2391 xt_compat_unlock(NFPROTO_BRIDGE);
2392 mutex_unlock(&ebt_mutex);
2393 return ret;
2394 }
2395 #endif
2396
2397 static struct nf_sockopt_ops ebt_sockopts = {
2398 .pf = PF_INET,
2399 .set_optmin = EBT_BASE_CTL,
2400 .set_optmax = EBT_SO_SET_MAX + 1,
2401 .set = do_ebt_set_ctl,
2402 #ifdef CONFIG_COMPAT
2403 .compat_set = compat_do_ebt_set_ctl,
2404 #endif
2405 .get_optmin = EBT_BASE_CTL,
2406 .get_optmax = EBT_SO_GET_MAX + 1,
2407 .get = do_ebt_get_ctl,
2408 #ifdef CONFIG_COMPAT
2409 .compat_get = compat_do_ebt_get_ctl,
2410 #endif
2411 .owner = THIS_MODULE,
2412 };
2413
2414 static int __init ebtables_init(void)
2415 {
2416 int ret;
2417
2418 ret = xt_register_target(&ebt_standard_target);
2419 if (ret < 0)
2420 return ret;
2421 ret = nf_register_sockopt(&ebt_sockopts);
2422 if (ret < 0) {
2423 xt_unregister_target(&ebt_standard_target);
2424 return ret;
2425 }
2426
2427 printk(KERN_INFO "Ebtables v2.0 registered\n");
2428 return 0;
2429 }
2430
2431 static void __exit ebtables_fini(void)
2432 {
2433 nf_unregister_sockopt(&ebt_sockopts);
2434 xt_unregister_target(&ebt_standard_target);
2435 printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2436 }
2437
2438 EXPORT_SYMBOL(ebt_register_table);
2439 EXPORT_SYMBOL(ebt_unregister_table);
2440 EXPORT_SYMBOL(ebt_do_table);
2441 module_init(ebtables_init);
2442 module_exit(ebtables_fini);
2443 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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