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[mirror_ubuntu-focal-kernel.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 <linux/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_thresh */
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.state = state;
198 acpar.hotdrop = false;
199
200 read_lock_bh(&table->lock);
201 private = table->private;
202 cb_base = COUNTER_BASE(private->counters, private->nentries,
203 smp_processor_id());
204 if (private->chainstack)
205 cs = private->chainstack[smp_processor_id()];
206 else
207 cs = NULL;
208 chaininfo = private->hook_entry[hook];
209 nentries = private->hook_entry[hook]->nentries;
210 point = (struct ebt_entry *)(private->hook_entry[hook]->data);
211 counter_base = cb_base + private->hook_entry[hook]->counter_offset;
212 /* base for chain jumps */
213 base = private->entries;
214 i = 0;
215 while (i < nentries) {
216 if (ebt_basic_match(point, skb, state->in, state->out))
217 goto letscontinue;
218
219 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
220 goto letscontinue;
221 if (acpar.hotdrop) {
222 read_unlock_bh(&table->lock);
223 return NF_DROP;
224 }
225
226 /* increase counter */
227 (*(counter_base + i)).pcnt++;
228 (*(counter_base + i)).bcnt += skb->len;
229
230 /* these should only watch: not modify, nor tell us
231 * what to do with the packet
232 */
233 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
234
235 t = (struct ebt_entry_target *)
236 (((char *)point) + point->target_offset);
237 /* standard target */
238 if (!t->u.target->target)
239 verdict = ((struct ebt_standard_target *)t)->verdict;
240 else {
241 acpar.target = t->u.target;
242 acpar.targinfo = t->data;
243 verdict = t->u.target->target(skb, &acpar);
244 }
245 if (verdict == EBT_ACCEPT) {
246 read_unlock_bh(&table->lock);
247 return NF_ACCEPT;
248 }
249 if (verdict == EBT_DROP) {
250 read_unlock_bh(&table->lock);
251 return NF_DROP;
252 }
253 if (verdict == EBT_RETURN) {
254 letsreturn:
255 if (WARN(sp == 0, "RETURN on base chain")) {
256 /* act like this is EBT_CONTINUE */
257 goto letscontinue;
258 }
259
260 sp--;
261 /* put all the local variables right */
262 i = cs[sp].n;
263 chaininfo = cs[sp].chaininfo;
264 nentries = chaininfo->nentries;
265 point = cs[sp].e;
266 counter_base = cb_base +
267 chaininfo->counter_offset;
268 continue;
269 }
270 if (verdict == EBT_CONTINUE)
271 goto letscontinue;
272
273 if (WARN(verdict < 0, "bogus standard verdict\n")) {
274 read_unlock_bh(&table->lock);
275 return NF_DROP;
276 }
277
278 /* jump to a udc */
279 cs[sp].n = i + 1;
280 cs[sp].chaininfo = chaininfo;
281 cs[sp].e = ebt_next_entry(point);
282 i = 0;
283 chaininfo = (struct ebt_entries *) (base + verdict);
284
285 if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
286 read_unlock_bh(&table->lock);
287 return NF_DROP;
288 }
289
290 nentries = chaininfo->nentries;
291 point = (struct ebt_entry *)chaininfo->data;
292 counter_base = cb_base + chaininfo->counter_offset;
293 sp++;
294 continue;
295 letscontinue:
296 point = ebt_next_entry(point);
297 i++;
298 }
299
300 /* I actually like this :) */
301 if (chaininfo->policy == EBT_RETURN)
302 goto letsreturn;
303 if (chaininfo->policy == EBT_ACCEPT) {
304 read_unlock_bh(&table->lock);
305 return NF_ACCEPT;
306 }
307 read_unlock_bh(&table->lock);
308 return NF_DROP;
309 }
310
311 /* If it succeeds, returns element and locks mutex */
312 static inline void *
313 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
314 struct mutex *mutex)
315 {
316 struct {
317 struct list_head list;
318 char name[EBT_FUNCTION_MAXNAMELEN];
319 } *e;
320
321 mutex_lock(mutex);
322 list_for_each_entry(e, head, list) {
323 if (strcmp(e->name, name) == 0)
324 return e;
325 }
326 *error = -ENOENT;
327 mutex_unlock(mutex);
328 return NULL;
329 }
330
331 static void *
332 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
333 int *error, struct mutex *mutex)
334 {
335 return try_then_request_module(
336 find_inlist_lock_noload(head, name, error, mutex),
337 "%s%s", prefix, name);
338 }
339
340 static inline struct ebt_table *
341 find_table_lock(struct net *net, const char *name, int *error,
342 struct mutex *mutex)
343 {
344 return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
345 "ebtable_", error, mutex);
346 }
347
348 static inline int
349 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
350 unsigned int *cnt)
351 {
352 const struct ebt_entry *e = par->entryinfo;
353 struct xt_match *match;
354 size_t left = ((char *)e + e->watchers_offset) - (char *)m;
355 int ret;
356
357 if (left < sizeof(struct ebt_entry_match) ||
358 left - sizeof(struct ebt_entry_match) < m->match_size)
359 return -EINVAL;
360
361 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
362 if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
363 if (!IS_ERR(match))
364 module_put(match->me);
365 request_module("ebt_%s", m->u.name);
366 match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
367 }
368 if (IS_ERR(match))
369 return PTR_ERR(match);
370 m->u.match = match;
371
372 par->match = match;
373 par->matchinfo = m->data;
374 ret = xt_check_match(par, m->match_size,
375 e->ethproto, e->invflags & EBT_IPROTO);
376 if (ret < 0) {
377 module_put(match->me);
378 return ret;
379 }
380
381 (*cnt)++;
382 return 0;
383 }
384
385 static inline int
386 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
387 unsigned int *cnt)
388 {
389 const struct ebt_entry *e = par->entryinfo;
390 struct xt_target *watcher;
391 size_t left = ((char *)e + e->target_offset) - (char *)w;
392 int ret;
393
394 if (left < sizeof(struct ebt_entry_watcher) ||
395 left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
396 return -EINVAL;
397
398 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
399 if (IS_ERR(watcher))
400 return PTR_ERR(watcher);
401 w->u.watcher = watcher;
402
403 par->target = watcher;
404 par->targinfo = w->data;
405 ret = xt_check_target(par, w->watcher_size,
406 e->ethproto, e->invflags & EBT_IPROTO);
407 if (ret < 0) {
408 module_put(watcher->me);
409 return ret;
410 }
411
412 (*cnt)++;
413 return 0;
414 }
415
416 static int ebt_verify_pointers(const struct ebt_replace *repl,
417 struct ebt_table_info *newinfo)
418 {
419 unsigned int limit = repl->entries_size;
420 unsigned int valid_hooks = repl->valid_hooks;
421 unsigned int offset = 0;
422 int i;
423
424 for (i = 0; i < NF_BR_NUMHOOKS; i++)
425 newinfo->hook_entry[i] = NULL;
426
427 newinfo->entries_size = repl->entries_size;
428 newinfo->nentries = repl->nentries;
429
430 while (offset < limit) {
431 size_t left = limit - offset;
432 struct ebt_entry *e = (void *)newinfo->entries + offset;
433
434 if (left < sizeof(unsigned int))
435 break;
436
437 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
438 if ((valid_hooks & (1 << i)) == 0)
439 continue;
440 if ((char __user *)repl->hook_entry[i] ==
441 repl->entries + offset)
442 break;
443 }
444
445 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
446 if (e->bitmask != 0) {
447 /* we make userspace set this right,
448 * so there is no misunderstanding
449 */
450 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
451 "in distinguisher\n");
452 return -EINVAL;
453 }
454 if (i != NF_BR_NUMHOOKS)
455 newinfo->hook_entry[i] = (struct ebt_entries *)e;
456 if (left < sizeof(struct ebt_entries))
457 break;
458 offset += sizeof(struct ebt_entries);
459 } else {
460 if (left < sizeof(struct ebt_entry))
461 break;
462 if (left < e->next_offset)
463 break;
464 if (e->next_offset < sizeof(struct ebt_entry))
465 return -EINVAL;
466 offset += e->next_offset;
467 }
468 }
469 if (offset != limit) {
470 BUGPRINT("entries_size too small\n");
471 return -EINVAL;
472 }
473
474 /* check if all valid hooks have a chain */
475 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
476 if (!newinfo->hook_entry[i] &&
477 (valid_hooks & (1 << i))) {
478 BUGPRINT("Valid hook without chain\n");
479 return -EINVAL;
480 }
481 }
482 return 0;
483 }
484
485 /* this one is very careful, as it is the first function
486 * to parse the userspace data
487 */
488 static inline int
489 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
490 const struct ebt_table_info *newinfo,
491 unsigned int *n, unsigned int *cnt,
492 unsigned int *totalcnt, unsigned int *udc_cnt)
493 {
494 int i;
495
496 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
497 if ((void *)e == (void *)newinfo->hook_entry[i])
498 break;
499 }
500 /* beginning of a new chain
501 * if i == NF_BR_NUMHOOKS it must be a user defined chain
502 */
503 if (i != NF_BR_NUMHOOKS || !e->bitmask) {
504 /* this checks if the previous chain has as many entries
505 * as it said it has
506 */
507 if (*n != *cnt) {
508 BUGPRINT("nentries does not equal the nr of entries "
509 "in the chain\n");
510 return -EINVAL;
511 }
512 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
513 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
514 /* only RETURN from udc */
515 if (i != NF_BR_NUMHOOKS ||
516 ((struct ebt_entries *)e)->policy != EBT_RETURN) {
517 BUGPRINT("bad policy\n");
518 return -EINVAL;
519 }
520 }
521 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
522 (*udc_cnt)++;
523 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
524 BUGPRINT("counter_offset != totalcnt");
525 return -EINVAL;
526 }
527 *n = ((struct ebt_entries *)e)->nentries;
528 *cnt = 0;
529 return 0;
530 }
531 /* a plain old entry, heh */
532 if (sizeof(struct ebt_entry) > e->watchers_offset ||
533 e->watchers_offset > e->target_offset ||
534 e->target_offset >= e->next_offset) {
535 BUGPRINT("entry offsets not in right order\n");
536 return -EINVAL;
537 }
538 /* this is not checked anywhere else */
539 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
540 BUGPRINT("target size too small\n");
541 return -EINVAL;
542 }
543 (*cnt)++;
544 (*totalcnt)++;
545 return 0;
546 }
547
548 struct ebt_cl_stack {
549 struct ebt_chainstack cs;
550 int from;
551 unsigned int hookmask;
552 };
553
554 /* We need these positions to check that the jumps to a different part of the
555 * entries is a jump to the beginning of a new chain.
556 */
557 static inline int
558 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
559 unsigned int *n, struct ebt_cl_stack *udc)
560 {
561 int i;
562
563 /* we're only interested in chain starts */
564 if (e->bitmask)
565 return 0;
566 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
567 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
568 break;
569 }
570 /* only care about udc */
571 if (i != NF_BR_NUMHOOKS)
572 return 0;
573
574 udc[*n].cs.chaininfo = (struct ebt_entries *)e;
575 /* these initialisations are depended on later in check_chainloops() */
576 udc[*n].cs.n = 0;
577 udc[*n].hookmask = 0;
578
579 (*n)++;
580 return 0;
581 }
582
583 static inline int
584 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
585 {
586 struct xt_mtdtor_param par;
587
588 if (i && (*i)-- == 0)
589 return 1;
590
591 par.net = net;
592 par.match = m->u.match;
593 par.matchinfo = m->data;
594 par.family = NFPROTO_BRIDGE;
595 if (par.match->destroy != NULL)
596 par.match->destroy(&par);
597 module_put(par.match->me);
598 return 0;
599 }
600
601 static inline int
602 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
603 {
604 struct xt_tgdtor_param par;
605
606 if (i && (*i)-- == 0)
607 return 1;
608
609 par.net = net;
610 par.target = w->u.watcher;
611 par.targinfo = w->data;
612 par.family = NFPROTO_BRIDGE;
613 if (par.target->destroy != NULL)
614 par.target->destroy(&par);
615 module_put(par.target->me);
616 return 0;
617 }
618
619 static inline int
620 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
621 {
622 struct xt_tgdtor_param par;
623 struct ebt_entry_target *t;
624
625 if (e->bitmask == 0)
626 return 0;
627 /* we're done */
628 if (cnt && (*cnt)-- == 0)
629 return 1;
630 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
631 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
632 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
633
634 par.net = net;
635 par.target = t->u.target;
636 par.targinfo = t->data;
637 par.family = NFPROTO_BRIDGE;
638 if (par.target->destroy != NULL)
639 par.target->destroy(&par);
640 module_put(par.target->me);
641 return 0;
642 }
643
644 static inline int
645 ebt_check_entry(struct ebt_entry *e, struct net *net,
646 const struct ebt_table_info *newinfo,
647 const char *name, unsigned int *cnt,
648 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
649 {
650 struct ebt_entry_target *t;
651 struct xt_target *target;
652 unsigned int i, j, hook = 0, hookmask = 0;
653 size_t gap;
654 int ret;
655 struct xt_mtchk_param mtpar;
656 struct xt_tgchk_param tgpar;
657
658 /* don't mess with the struct ebt_entries */
659 if (e->bitmask == 0)
660 return 0;
661
662 if (e->bitmask & ~EBT_F_MASK) {
663 BUGPRINT("Unknown flag for bitmask\n");
664 return -EINVAL;
665 }
666 if (e->invflags & ~EBT_INV_MASK) {
667 BUGPRINT("Unknown flag for inv bitmask\n");
668 return -EINVAL;
669 }
670 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
671 BUGPRINT("NOPROTO & 802_3 not allowed\n");
672 return -EINVAL;
673 }
674 /* what hook do we belong to? */
675 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
676 if (!newinfo->hook_entry[i])
677 continue;
678 if ((char *)newinfo->hook_entry[i] < (char *)e)
679 hook = i;
680 else
681 break;
682 }
683 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
684 * a base chain
685 */
686 if (i < NF_BR_NUMHOOKS)
687 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
688 else {
689 for (i = 0; i < udc_cnt; i++)
690 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
691 break;
692 if (i == 0)
693 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
694 else
695 hookmask = cl_s[i - 1].hookmask;
696 }
697 i = 0;
698
699 mtpar.net = tgpar.net = net;
700 mtpar.table = tgpar.table = name;
701 mtpar.entryinfo = tgpar.entryinfo = e;
702 mtpar.hook_mask = tgpar.hook_mask = hookmask;
703 mtpar.family = tgpar.family = NFPROTO_BRIDGE;
704 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
705 if (ret != 0)
706 goto cleanup_matches;
707 j = 0;
708 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
709 if (ret != 0)
710 goto cleanup_watchers;
711 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
712 gap = e->next_offset - e->target_offset;
713
714 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
715 if (IS_ERR(target)) {
716 ret = PTR_ERR(target);
717 goto cleanup_watchers;
718 }
719
720 t->u.target = target;
721 if (t->u.target == &ebt_standard_target) {
722 if (gap < sizeof(struct ebt_standard_target)) {
723 BUGPRINT("Standard target size too big\n");
724 ret = -EFAULT;
725 goto cleanup_watchers;
726 }
727 if (((struct ebt_standard_target *)t)->verdict <
728 -NUM_STANDARD_TARGETS) {
729 BUGPRINT("Invalid standard target\n");
730 ret = -EFAULT;
731 goto cleanup_watchers;
732 }
733 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
734 module_put(t->u.target->me);
735 ret = -EFAULT;
736 goto cleanup_watchers;
737 }
738
739 tgpar.target = target;
740 tgpar.targinfo = t->data;
741 ret = xt_check_target(&tgpar, t->target_size,
742 e->ethproto, e->invflags & EBT_IPROTO);
743 if (ret < 0) {
744 module_put(target->me);
745 goto cleanup_watchers;
746 }
747 (*cnt)++;
748 return 0;
749 cleanup_watchers:
750 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
751 cleanup_matches:
752 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
753 return ret;
754 }
755
756 /* checks for loops and sets the hook mask for udc
757 * the hook mask for udc tells us from which base chains the udc can be
758 * accessed. This mask is a parameter to the check() functions of the extensions
759 */
760 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
761 unsigned int udc_cnt, unsigned int hooknr, char *base)
762 {
763 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
764 const struct ebt_entry *e = (struct ebt_entry *)chain->data;
765 const struct ebt_entry_target *t;
766
767 while (pos < nentries || chain_nr != -1) {
768 /* end of udc, go back one 'recursion' step */
769 if (pos == nentries) {
770 /* put back values of the time when this chain was called */
771 e = cl_s[chain_nr].cs.e;
772 if (cl_s[chain_nr].from != -1)
773 nentries =
774 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
775 else
776 nentries = chain->nentries;
777 pos = cl_s[chain_nr].cs.n;
778 /* make sure we won't see a loop that isn't one */
779 cl_s[chain_nr].cs.n = 0;
780 chain_nr = cl_s[chain_nr].from;
781 if (pos == nentries)
782 continue;
783 }
784 t = (struct ebt_entry_target *)
785 (((char *)e) + e->target_offset);
786 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
787 goto letscontinue;
788 if (e->target_offset + sizeof(struct ebt_standard_target) >
789 e->next_offset) {
790 BUGPRINT("Standard target size too big\n");
791 return -1;
792 }
793 verdict = ((struct ebt_standard_target *)t)->verdict;
794 if (verdict >= 0) { /* jump to another chain */
795 struct ebt_entries *hlp2 =
796 (struct ebt_entries *)(base + verdict);
797 for (i = 0; i < udc_cnt; i++)
798 if (hlp2 == cl_s[i].cs.chaininfo)
799 break;
800 /* bad destination or loop */
801 if (i == udc_cnt) {
802 BUGPRINT("bad destination\n");
803 return -1;
804 }
805 if (cl_s[i].cs.n) {
806 BUGPRINT("loop\n");
807 return -1;
808 }
809 if (cl_s[i].hookmask & (1 << hooknr))
810 goto letscontinue;
811 /* this can't be 0, so the loop test is correct */
812 cl_s[i].cs.n = pos + 1;
813 pos = 0;
814 cl_s[i].cs.e = ebt_next_entry(e);
815 e = (struct ebt_entry *)(hlp2->data);
816 nentries = hlp2->nentries;
817 cl_s[i].from = chain_nr;
818 chain_nr = i;
819 /* this udc is accessible from the base chain for hooknr */
820 cl_s[i].hookmask |= (1 << hooknr);
821 continue;
822 }
823 letscontinue:
824 e = ebt_next_entry(e);
825 pos++;
826 }
827 return 0;
828 }
829
830 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
831 static int translate_table(struct net *net, const char *name,
832 struct ebt_table_info *newinfo)
833 {
834 unsigned int i, j, k, udc_cnt;
835 int ret;
836 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
837
838 i = 0;
839 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
840 i++;
841 if (i == NF_BR_NUMHOOKS) {
842 BUGPRINT("No valid hooks specified\n");
843 return -EINVAL;
844 }
845 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
846 BUGPRINT("Chains don't start at beginning\n");
847 return -EINVAL;
848 }
849 /* make sure chains are ordered after each other in same order
850 * as their corresponding hooks
851 */
852 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
853 if (!newinfo->hook_entry[j])
854 continue;
855 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
856 BUGPRINT("Hook order must be followed\n");
857 return -EINVAL;
858 }
859 i = j;
860 }
861
862 /* do some early checkings and initialize some things */
863 i = 0; /* holds the expected nr. of entries for the chain */
864 j = 0; /* holds the up to now counted entries for the chain */
865 k = 0; /* holds the total nr. of entries, should equal
866 * newinfo->nentries afterwards
867 */
868 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
869 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
870 ebt_check_entry_size_and_hooks, newinfo,
871 &i, &j, &k, &udc_cnt);
872
873 if (ret != 0)
874 return ret;
875
876 if (i != j) {
877 BUGPRINT("nentries does not equal the nr of entries in the "
878 "(last) chain\n");
879 return -EINVAL;
880 }
881 if (k != newinfo->nentries) {
882 BUGPRINT("Total nentries is wrong\n");
883 return -EINVAL;
884 }
885
886 /* get the location of the udc, put them in an array
887 * while we're at it, allocate the chainstack
888 */
889 if (udc_cnt) {
890 /* this will get free'd in do_replace()/ebt_register_table()
891 * if an error occurs
892 */
893 newinfo->chainstack =
894 vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
895 if (!newinfo->chainstack)
896 return -ENOMEM;
897 for_each_possible_cpu(i) {
898 newinfo->chainstack[i] =
899 vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
900 if (!newinfo->chainstack[i]) {
901 while (i)
902 vfree(newinfo->chainstack[--i]);
903 vfree(newinfo->chainstack);
904 newinfo->chainstack = NULL;
905 return -ENOMEM;
906 }
907 }
908
909 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
910 if (!cl_s)
911 return -ENOMEM;
912 i = 0; /* the i'th udc */
913 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
914 ebt_get_udc_positions, newinfo, &i, cl_s);
915 /* sanity check */
916 if (i != udc_cnt) {
917 BUGPRINT("i != udc_cnt\n");
918 vfree(cl_s);
919 return -EFAULT;
920 }
921 }
922
923 /* Check for loops */
924 for (i = 0; i < NF_BR_NUMHOOKS; i++)
925 if (newinfo->hook_entry[i])
926 if (check_chainloops(newinfo->hook_entry[i],
927 cl_s, udc_cnt, i, newinfo->entries)) {
928 vfree(cl_s);
929 return -EINVAL;
930 }
931
932 /* we now know the following (along with E=mc²):
933 * - the nr of entries in each chain is right
934 * - the size of the allocated space is right
935 * - all valid hooks have a corresponding chain
936 * - there are no loops
937 * - wrong data can still be on the level of a single entry
938 * - could be there are jumps to places that are not the
939 * beginning of a chain. This can only occur in chains that
940 * are not accessible from any base chains, so we don't care.
941 */
942
943 /* used to know what we need to clean up if something goes wrong */
944 i = 0;
945 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
946 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
947 if (ret != 0) {
948 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
949 ebt_cleanup_entry, net, &i);
950 }
951 vfree(cl_s);
952 return ret;
953 }
954
955 /* called under write_lock */
956 static void get_counters(const struct ebt_counter *oldcounters,
957 struct ebt_counter *counters, unsigned int nentries)
958 {
959 int i, cpu;
960 struct ebt_counter *counter_base;
961
962 /* counters of cpu 0 */
963 memcpy(counters, oldcounters,
964 sizeof(struct ebt_counter) * nentries);
965
966 /* add other counters to those of cpu 0 */
967 for_each_possible_cpu(cpu) {
968 if (cpu == 0)
969 continue;
970 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
971 for (i = 0; i < nentries; i++) {
972 counters[i].pcnt += counter_base[i].pcnt;
973 counters[i].bcnt += counter_base[i].bcnt;
974 }
975 }
976 }
977
978 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
979 struct ebt_table_info *newinfo)
980 {
981 int ret, i;
982 struct ebt_counter *counterstmp = NULL;
983 /* used to be able to unlock earlier */
984 struct ebt_table_info *table;
985 struct ebt_table *t;
986
987 /* the user wants counters back
988 * the check on the size is done later, when we have the lock
989 */
990 if (repl->num_counters) {
991 unsigned long size = repl->num_counters * sizeof(*counterstmp);
992 counterstmp = vmalloc(size);
993 if (!counterstmp)
994 return -ENOMEM;
995 }
996
997 newinfo->chainstack = NULL;
998 ret = ebt_verify_pointers(repl, newinfo);
999 if (ret != 0)
1000 goto free_counterstmp;
1001
1002 ret = translate_table(net, repl->name, newinfo);
1003
1004 if (ret != 0)
1005 goto free_counterstmp;
1006
1007 t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1008 if (!t) {
1009 ret = -ENOENT;
1010 goto free_iterate;
1011 }
1012
1013 /* the table doesn't like it */
1014 if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1015 goto free_unlock;
1016
1017 if (repl->num_counters && repl->num_counters != t->private->nentries) {
1018 BUGPRINT("Wrong nr. of counters requested\n");
1019 ret = -EINVAL;
1020 goto free_unlock;
1021 }
1022
1023 /* we have the mutex lock, so no danger in reading this pointer */
1024 table = t->private;
1025 /* make sure the table can only be rmmod'ed if it contains no rules */
1026 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1027 ret = -ENOENT;
1028 goto free_unlock;
1029 } else if (table->nentries && !newinfo->nentries)
1030 module_put(t->me);
1031 /* we need an atomic snapshot of the counters */
1032 write_lock_bh(&t->lock);
1033 if (repl->num_counters)
1034 get_counters(t->private->counters, counterstmp,
1035 t->private->nentries);
1036
1037 t->private = newinfo;
1038 write_unlock_bh(&t->lock);
1039 mutex_unlock(&ebt_mutex);
1040 /* so, a user can change the chains while having messed up her counter
1041 * allocation. Only reason why this is done is because this way the lock
1042 * is held only once, while this doesn't bring the kernel into a
1043 * dangerous state.
1044 */
1045 if (repl->num_counters &&
1046 copy_to_user(repl->counters, counterstmp,
1047 repl->num_counters * sizeof(struct ebt_counter))) {
1048 /* Silent error, can't fail, new table is already in place */
1049 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1050 }
1051
1052 /* decrease module count and free resources */
1053 EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1054 ebt_cleanup_entry, net, NULL);
1055
1056 vfree(table->entries);
1057 if (table->chainstack) {
1058 for_each_possible_cpu(i)
1059 vfree(table->chainstack[i]);
1060 vfree(table->chainstack);
1061 }
1062 vfree(table);
1063
1064 vfree(counterstmp);
1065
1066 #ifdef CONFIG_AUDIT
1067 if (audit_enabled) {
1068 audit_log(current->audit_context, GFP_KERNEL,
1069 AUDIT_NETFILTER_CFG,
1070 "table=%s family=%u entries=%u",
1071 repl->name, AF_BRIDGE, repl->nentries);
1072 }
1073 #endif
1074 return ret;
1075
1076 free_unlock:
1077 mutex_unlock(&ebt_mutex);
1078 free_iterate:
1079 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1080 ebt_cleanup_entry, net, NULL);
1081 free_counterstmp:
1082 vfree(counterstmp);
1083 /* can be initialized in translate_table() */
1084 if (newinfo->chainstack) {
1085 for_each_possible_cpu(i)
1086 vfree(newinfo->chainstack[i]);
1087 vfree(newinfo->chainstack);
1088 }
1089 return ret;
1090 }
1091
1092 /* replace the table */
1093 static int do_replace(struct net *net, const void __user *user,
1094 unsigned int len)
1095 {
1096 int ret, countersize;
1097 struct ebt_table_info *newinfo;
1098 struct ebt_replace tmp;
1099
1100 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1101 return -EFAULT;
1102
1103 if (len != sizeof(tmp) + tmp.entries_size) {
1104 BUGPRINT("Wrong len argument\n");
1105 return -EINVAL;
1106 }
1107
1108 if (tmp.entries_size == 0) {
1109 BUGPRINT("Entries_size never zero\n");
1110 return -EINVAL;
1111 }
1112 /* overflow check */
1113 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1114 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1115 return -ENOMEM;
1116 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1117 return -ENOMEM;
1118
1119 tmp.name[sizeof(tmp.name) - 1] = 0;
1120
1121 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1122 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1123 if (!newinfo)
1124 return -ENOMEM;
1125
1126 if (countersize)
1127 memset(newinfo->counters, 0, countersize);
1128
1129 newinfo->entries = vmalloc(tmp.entries_size);
1130 if (!newinfo->entries) {
1131 ret = -ENOMEM;
1132 goto free_newinfo;
1133 }
1134 if (copy_from_user(
1135 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1136 BUGPRINT("Couldn't copy entries from userspace\n");
1137 ret = -EFAULT;
1138 goto free_entries;
1139 }
1140
1141 ret = do_replace_finish(net, &tmp, newinfo);
1142 if (ret == 0)
1143 return ret;
1144 free_entries:
1145 vfree(newinfo->entries);
1146 free_newinfo:
1147 vfree(newinfo);
1148 return ret;
1149 }
1150
1151 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1152 {
1153 int i;
1154
1155 mutex_lock(&ebt_mutex);
1156 list_del(&table->list);
1157 mutex_unlock(&ebt_mutex);
1158 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1159 ebt_cleanup_entry, net, NULL);
1160 if (table->private->nentries)
1161 module_put(table->me);
1162 vfree(table->private->entries);
1163 if (table->private->chainstack) {
1164 for_each_possible_cpu(i)
1165 vfree(table->private->chainstack[i]);
1166 vfree(table->private->chainstack);
1167 }
1168 vfree(table->private);
1169 kfree(table);
1170 }
1171
1172 struct ebt_table *
1173 ebt_register_table(struct net *net, const struct ebt_table *input_table,
1174 const struct nf_hook_ops *ops)
1175 {
1176 struct ebt_table_info *newinfo;
1177 struct ebt_table *t, *table;
1178 struct ebt_replace_kernel *repl;
1179 int ret, i, countersize;
1180 void *p;
1181
1182 if (input_table == NULL || (repl = input_table->table) == NULL ||
1183 repl->entries == NULL || repl->entries_size == 0 ||
1184 repl->counters != NULL || input_table->private != NULL) {
1185 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1186 return ERR_PTR(-EINVAL);
1187 }
1188
1189 /* Don't add one table to multiple lists. */
1190 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1191 if (!table) {
1192 ret = -ENOMEM;
1193 goto out;
1194 }
1195
1196 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1197 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1198 ret = -ENOMEM;
1199 if (!newinfo)
1200 goto free_table;
1201
1202 p = vmalloc(repl->entries_size);
1203 if (!p)
1204 goto free_newinfo;
1205
1206 memcpy(p, repl->entries, repl->entries_size);
1207 newinfo->entries = p;
1208
1209 newinfo->entries_size = repl->entries_size;
1210 newinfo->nentries = repl->nentries;
1211
1212 if (countersize)
1213 memset(newinfo->counters, 0, countersize);
1214
1215 /* fill in newinfo and parse the entries */
1216 newinfo->chainstack = NULL;
1217 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1218 if ((repl->valid_hooks & (1 << i)) == 0)
1219 newinfo->hook_entry[i] = NULL;
1220 else
1221 newinfo->hook_entry[i] = p +
1222 ((char *)repl->hook_entry[i] - repl->entries);
1223 }
1224 ret = translate_table(net, repl->name, newinfo);
1225 if (ret != 0) {
1226 BUGPRINT("Translate_table failed\n");
1227 goto free_chainstack;
1228 }
1229
1230 if (table->check && table->check(newinfo, table->valid_hooks)) {
1231 BUGPRINT("The table doesn't like its own initial data, lol\n");
1232 ret = -EINVAL;
1233 goto free_chainstack;
1234 }
1235
1236 table->private = newinfo;
1237 rwlock_init(&table->lock);
1238 mutex_lock(&ebt_mutex);
1239 list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1240 if (strcmp(t->name, table->name) == 0) {
1241 ret = -EEXIST;
1242 BUGPRINT("Table name already exists\n");
1243 goto free_unlock;
1244 }
1245 }
1246
1247 /* Hold a reference count if the chains aren't empty */
1248 if (newinfo->nentries && !try_module_get(table->me)) {
1249 ret = -ENOENT;
1250 goto free_unlock;
1251 }
1252 list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1253 mutex_unlock(&ebt_mutex);
1254
1255 if (!ops)
1256 return table;
1257
1258 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1259 if (ret) {
1260 __ebt_unregister_table(net, table);
1261 return ERR_PTR(ret);
1262 }
1263
1264 return table;
1265 free_unlock:
1266 mutex_unlock(&ebt_mutex);
1267 free_chainstack:
1268 if (newinfo->chainstack) {
1269 for_each_possible_cpu(i)
1270 vfree(newinfo->chainstack[i]);
1271 vfree(newinfo->chainstack);
1272 }
1273 vfree(newinfo->entries);
1274 free_newinfo:
1275 vfree(newinfo);
1276 free_table:
1277 kfree(table);
1278 out:
1279 return ERR_PTR(ret);
1280 }
1281
1282 void ebt_unregister_table(struct net *net, struct ebt_table *table,
1283 const struct nf_hook_ops *ops)
1284 {
1285 if (ops)
1286 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1287 __ebt_unregister_table(net, 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_obj_to_user(char __user *um, const char *_name,
1356 const char *data, int entrysize,
1357 int usersize, int datasize)
1358 {
1359 char name[EBT_FUNCTION_MAXNAMELEN] = {0};
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, _name, sizeof(name));
1365 if (copy_to_user(um, name, EBT_FUNCTION_MAXNAMELEN) ||
1366 put_user(datasize, (int __user *)(um + EBT_FUNCTION_MAXNAMELEN)) ||
1367 xt_data_to_user(um + entrysize, data, usersize, datasize,
1368 XT_ALIGN(datasize)))
1369 return -EFAULT;
1370
1371 return 0;
1372 }
1373
1374 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1375 const char *base, char __user *ubase)
1376 {
1377 return ebt_obj_to_user(ubase + ((char *)m - base),
1378 m->u.match->name, m->data, sizeof(*m),
1379 m->u.match->usersize, m->match_size);
1380 }
1381
1382 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1383 const char *base, char __user *ubase)
1384 {
1385 return ebt_obj_to_user(ubase + ((char *)w - base),
1386 w->u.watcher->name, w->data, sizeof(*w),
1387 w->u.watcher->usersize, w->watcher_size);
1388 }
1389
1390 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1391 char __user *ubase)
1392 {
1393 int ret;
1394 char __user *hlp;
1395 const struct ebt_entry_target *t;
1396
1397 if (e->bitmask == 0) {
1398 /* special case !EBT_ENTRY_OR_ENTRIES */
1399 if (copy_to_user(ubase + ((char *)e - base), e,
1400 sizeof(struct ebt_entries)))
1401 return -EFAULT;
1402 return 0;
1403 }
1404
1405 if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1406 return -EFAULT;
1407
1408 hlp = ubase + (((char *)e + e->target_offset) - base);
1409 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1410
1411 ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1412 if (ret != 0)
1413 return ret;
1414 ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1415 if (ret != 0)
1416 return ret;
1417 ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1418 t->u.target->usersize, t->target_size);
1419 if (ret != 0)
1420 return ret;
1421
1422 return 0;
1423 }
1424
1425 static int copy_counters_to_user(struct ebt_table *t,
1426 const struct ebt_counter *oldcounters,
1427 void __user *user, unsigned int num_counters,
1428 unsigned int nentries)
1429 {
1430 struct ebt_counter *counterstmp;
1431 int ret = 0;
1432
1433 /* userspace might not need the counters */
1434 if (num_counters == 0)
1435 return 0;
1436
1437 if (num_counters != nentries) {
1438 BUGPRINT("Num_counters wrong\n");
1439 return -EINVAL;
1440 }
1441
1442 counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1443 if (!counterstmp)
1444 return -ENOMEM;
1445
1446 write_lock_bh(&t->lock);
1447 get_counters(oldcounters, counterstmp, nentries);
1448 write_unlock_bh(&t->lock);
1449
1450 if (copy_to_user(user, counterstmp,
1451 nentries * sizeof(struct ebt_counter)))
1452 ret = -EFAULT;
1453 vfree(counterstmp);
1454 return ret;
1455 }
1456
1457 /* called with ebt_mutex locked */
1458 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1459 const int *len, int cmd)
1460 {
1461 struct ebt_replace tmp;
1462 const struct ebt_counter *oldcounters;
1463 unsigned int entries_size, nentries;
1464 int ret;
1465 char *entries;
1466
1467 if (cmd == EBT_SO_GET_ENTRIES) {
1468 entries_size = t->private->entries_size;
1469 nentries = t->private->nentries;
1470 entries = t->private->entries;
1471 oldcounters = t->private->counters;
1472 } else {
1473 entries_size = t->table->entries_size;
1474 nentries = t->table->nentries;
1475 entries = t->table->entries;
1476 oldcounters = t->table->counters;
1477 }
1478
1479 if (copy_from_user(&tmp, user, sizeof(tmp)))
1480 return -EFAULT;
1481
1482 if (*len != sizeof(struct ebt_replace) + entries_size +
1483 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1484 return -EINVAL;
1485
1486 if (tmp.nentries != nentries) {
1487 BUGPRINT("Nentries wrong\n");
1488 return -EINVAL;
1489 }
1490
1491 if (tmp.entries_size != entries_size) {
1492 BUGPRINT("Wrong size\n");
1493 return -EINVAL;
1494 }
1495
1496 ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1497 tmp.num_counters, nentries);
1498 if (ret)
1499 return ret;
1500
1501 /* set the match/watcher/target names right */
1502 return EBT_ENTRY_ITERATE(entries, entries_size,
1503 ebt_entry_to_user, entries, tmp.entries);
1504 }
1505
1506 static int do_ebt_set_ctl(struct sock *sk,
1507 int cmd, void __user *user, unsigned int len)
1508 {
1509 int ret;
1510 struct net *net = sock_net(sk);
1511
1512 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1513 return -EPERM;
1514
1515 switch (cmd) {
1516 case EBT_SO_SET_ENTRIES:
1517 ret = do_replace(net, user, len);
1518 break;
1519 case EBT_SO_SET_COUNTERS:
1520 ret = update_counters(net, user, len);
1521 break;
1522 default:
1523 ret = -EINVAL;
1524 }
1525 return ret;
1526 }
1527
1528 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1529 {
1530 int ret;
1531 struct ebt_replace tmp;
1532 struct ebt_table *t;
1533 struct net *net = sock_net(sk);
1534
1535 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1536 return -EPERM;
1537
1538 if (copy_from_user(&tmp, user, sizeof(tmp)))
1539 return -EFAULT;
1540
1541 tmp.name[sizeof(tmp.name) - 1] = '\0';
1542
1543 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1544 if (!t)
1545 return ret;
1546
1547 switch (cmd) {
1548 case EBT_SO_GET_INFO:
1549 case EBT_SO_GET_INIT_INFO:
1550 if (*len != sizeof(struct ebt_replace)) {
1551 ret = -EINVAL;
1552 mutex_unlock(&ebt_mutex);
1553 break;
1554 }
1555 if (cmd == EBT_SO_GET_INFO) {
1556 tmp.nentries = t->private->nentries;
1557 tmp.entries_size = t->private->entries_size;
1558 tmp.valid_hooks = t->valid_hooks;
1559 } else {
1560 tmp.nentries = t->table->nentries;
1561 tmp.entries_size = t->table->entries_size;
1562 tmp.valid_hooks = t->table->valid_hooks;
1563 }
1564 mutex_unlock(&ebt_mutex);
1565 if (copy_to_user(user, &tmp, *len) != 0) {
1566 BUGPRINT("c2u Didn't work\n");
1567 ret = -EFAULT;
1568 break;
1569 }
1570 ret = 0;
1571 break;
1572
1573 case EBT_SO_GET_ENTRIES:
1574 case EBT_SO_GET_INIT_ENTRIES:
1575 ret = copy_everything_to_user(t, user, len, cmd);
1576 mutex_unlock(&ebt_mutex);
1577 break;
1578
1579 default:
1580 mutex_unlock(&ebt_mutex);
1581 ret = -EINVAL;
1582 }
1583
1584 return ret;
1585 }
1586
1587 #ifdef CONFIG_COMPAT
1588 /* 32 bit-userspace compatibility definitions. */
1589 struct compat_ebt_replace {
1590 char name[EBT_TABLE_MAXNAMELEN];
1591 compat_uint_t valid_hooks;
1592 compat_uint_t nentries;
1593 compat_uint_t entries_size;
1594 /* start of the chains */
1595 compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1596 /* nr of counters userspace expects back */
1597 compat_uint_t num_counters;
1598 /* where the kernel will put the old counters. */
1599 compat_uptr_t counters;
1600 compat_uptr_t entries;
1601 };
1602
1603 /* struct ebt_entry_match, _target and _watcher have same layout */
1604 struct compat_ebt_entry_mwt {
1605 union {
1606 char name[EBT_FUNCTION_MAXNAMELEN];
1607 compat_uptr_t ptr;
1608 } u;
1609 compat_uint_t match_size;
1610 compat_uint_t data[0];
1611 };
1612
1613 /* account for possible padding between match_size and ->data */
1614 static int ebt_compat_entry_padsize(void)
1615 {
1616 BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1617 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1618 return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1619 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1620 }
1621
1622 static int ebt_compat_match_offset(const struct xt_match *match,
1623 unsigned int userlen)
1624 {
1625 /* ebt_among needs special handling. The kernel .matchsize is
1626 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1627 * value is expected.
1628 * Example: userspace sends 4500, ebt_among.c wants 4504.
1629 */
1630 if (unlikely(match->matchsize == -1))
1631 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1632 return xt_compat_match_offset(match);
1633 }
1634
1635 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1636 unsigned int *size)
1637 {
1638 const struct xt_match *match = m->u.match;
1639 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1640 int off = ebt_compat_match_offset(match, m->match_size);
1641 compat_uint_t msize = m->match_size - off;
1642
1643 BUG_ON(off >= m->match_size);
1644
1645 if (copy_to_user(cm->u.name, match->name,
1646 strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1647 return -EFAULT;
1648
1649 if (match->compat_to_user) {
1650 if (match->compat_to_user(cm->data, m->data))
1651 return -EFAULT;
1652 } else {
1653 if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1654 COMPAT_XT_ALIGN(msize)))
1655 return -EFAULT;
1656 }
1657
1658 *size -= ebt_compat_entry_padsize() + off;
1659 *dstptr = cm->data;
1660 *dstptr += msize;
1661 return 0;
1662 }
1663
1664 static int compat_target_to_user(struct ebt_entry_target *t,
1665 void __user **dstptr,
1666 unsigned int *size)
1667 {
1668 const struct xt_target *target = t->u.target;
1669 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1670 int off = xt_compat_target_offset(target);
1671 compat_uint_t tsize = t->target_size - off;
1672
1673 BUG_ON(off >= t->target_size);
1674
1675 if (copy_to_user(cm->u.name, target->name,
1676 strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1677 return -EFAULT;
1678
1679 if (target->compat_to_user) {
1680 if (target->compat_to_user(cm->data, t->data))
1681 return -EFAULT;
1682 } else {
1683 if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1684 COMPAT_XT_ALIGN(tsize)))
1685 return -EFAULT;
1686 }
1687
1688 *size -= ebt_compat_entry_padsize() + off;
1689 *dstptr = cm->data;
1690 *dstptr += tsize;
1691 return 0;
1692 }
1693
1694 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1695 void __user **dstptr,
1696 unsigned int *size)
1697 {
1698 return compat_target_to_user((struct ebt_entry_target *)w,
1699 dstptr, size);
1700 }
1701
1702 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1703 unsigned int *size)
1704 {
1705 struct ebt_entry_target *t;
1706 struct ebt_entry __user *ce;
1707 u32 watchers_offset, target_offset, next_offset;
1708 compat_uint_t origsize;
1709 int ret;
1710
1711 if (e->bitmask == 0) {
1712 if (*size < sizeof(struct ebt_entries))
1713 return -EINVAL;
1714 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1715 return -EFAULT;
1716
1717 *dstptr += sizeof(struct ebt_entries);
1718 *size -= sizeof(struct ebt_entries);
1719 return 0;
1720 }
1721
1722 if (*size < sizeof(*ce))
1723 return -EINVAL;
1724
1725 ce = *dstptr;
1726 if (copy_to_user(ce, e, sizeof(*ce)))
1727 return -EFAULT;
1728
1729 origsize = *size;
1730 *dstptr += sizeof(*ce);
1731
1732 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1733 if (ret)
1734 return ret;
1735 watchers_offset = e->watchers_offset - (origsize - *size);
1736
1737 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1738 if (ret)
1739 return ret;
1740 target_offset = e->target_offset - (origsize - *size);
1741
1742 t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1743
1744 ret = compat_target_to_user(t, dstptr, size);
1745 if (ret)
1746 return ret;
1747 next_offset = e->next_offset - (origsize - *size);
1748
1749 if (put_user(watchers_offset, &ce->watchers_offset) ||
1750 put_user(target_offset, &ce->target_offset) ||
1751 put_user(next_offset, &ce->next_offset))
1752 return -EFAULT;
1753
1754 *size -= sizeof(*ce);
1755 return 0;
1756 }
1757
1758 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1759 {
1760 *off += ebt_compat_match_offset(m->u.match, m->match_size);
1761 *off += ebt_compat_entry_padsize();
1762 return 0;
1763 }
1764
1765 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1766 {
1767 *off += xt_compat_target_offset(w->u.watcher);
1768 *off += ebt_compat_entry_padsize();
1769 return 0;
1770 }
1771
1772 static int compat_calc_entry(const struct ebt_entry *e,
1773 const struct ebt_table_info *info,
1774 const void *base,
1775 struct compat_ebt_replace *newinfo)
1776 {
1777 const struct ebt_entry_target *t;
1778 unsigned int entry_offset;
1779 int off, ret, i;
1780
1781 if (e->bitmask == 0)
1782 return 0;
1783
1784 off = 0;
1785 entry_offset = (void *)e - base;
1786
1787 EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1788 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1789
1790 t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1791
1792 off += xt_compat_target_offset(t->u.target);
1793 off += ebt_compat_entry_padsize();
1794
1795 newinfo->entries_size -= off;
1796
1797 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1798 if (ret)
1799 return ret;
1800
1801 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1802 const void *hookptr = info->hook_entry[i];
1803 if (info->hook_entry[i] &&
1804 (e < (struct ebt_entry *)(base - hookptr))) {
1805 newinfo->hook_entry[i] -= off;
1806 pr_debug("0x%08X -> 0x%08X\n",
1807 newinfo->hook_entry[i] + off,
1808 newinfo->hook_entry[i]);
1809 }
1810 }
1811
1812 return 0;
1813 }
1814
1815
1816 static int compat_table_info(const struct ebt_table_info *info,
1817 struct compat_ebt_replace *newinfo)
1818 {
1819 unsigned int size = info->entries_size;
1820 const void *entries = info->entries;
1821
1822 newinfo->entries_size = size;
1823
1824 xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1825 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1826 entries, newinfo);
1827 }
1828
1829 static int compat_copy_everything_to_user(struct ebt_table *t,
1830 void __user *user, int *len, int cmd)
1831 {
1832 struct compat_ebt_replace repl, tmp;
1833 struct ebt_counter *oldcounters;
1834 struct ebt_table_info tinfo;
1835 int ret;
1836 void __user *pos;
1837
1838 memset(&tinfo, 0, sizeof(tinfo));
1839
1840 if (cmd == EBT_SO_GET_ENTRIES) {
1841 tinfo.entries_size = t->private->entries_size;
1842 tinfo.nentries = t->private->nentries;
1843 tinfo.entries = t->private->entries;
1844 oldcounters = t->private->counters;
1845 } else {
1846 tinfo.entries_size = t->table->entries_size;
1847 tinfo.nentries = t->table->nentries;
1848 tinfo.entries = t->table->entries;
1849 oldcounters = t->table->counters;
1850 }
1851
1852 if (copy_from_user(&tmp, user, sizeof(tmp)))
1853 return -EFAULT;
1854
1855 if (tmp.nentries != tinfo.nentries ||
1856 (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1857 return -EINVAL;
1858
1859 memcpy(&repl, &tmp, sizeof(repl));
1860 if (cmd == EBT_SO_GET_ENTRIES)
1861 ret = compat_table_info(t->private, &repl);
1862 else
1863 ret = compat_table_info(&tinfo, &repl);
1864 if (ret)
1865 return ret;
1866
1867 if (*len != sizeof(tmp) + repl.entries_size +
1868 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1869 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1870 *len, tinfo.entries_size, repl.entries_size);
1871 return -EINVAL;
1872 }
1873
1874 /* userspace might not need the counters */
1875 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1876 tmp.num_counters, tinfo.nentries);
1877 if (ret)
1878 return ret;
1879
1880 pos = compat_ptr(tmp.entries);
1881 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1882 compat_copy_entry_to_user, &pos, &tmp.entries_size);
1883 }
1884
1885 struct ebt_entries_buf_state {
1886 char *buf_kern_start; /* kernel buffer to copy (translated) data to */
1887 u32 buf_kern_len; /* total size of kernel buffer */
1888 u32 buf_kern_offset; /* amount of data copied so far */
1889 u32 buf_user_offset; /* read position in userspace buffer */
1890 };
1891
1892 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1893 {
1894 state->buf_kern_offset += sz;
1895 return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1896 }
1897
1898 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1899 void *data, unsigned int sz)
1900 {
1901 if (state->buf_kern_start == NULL)
1902 goto count_only;
1903
1904 BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1905
1906 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1907
1908 count_only:
1909 state->buf_user_offset += sz;
1910 return ebt_buf_count(state, sz);
1911 }
1912
1913 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1914 {
1915 char *b = state->buf_kern_start;
1916
1917 BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1918
1919 if (b != NULL && sz > 0)
1920 memset(b + state->buf_kern_offset, 0, sz);
1921 /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1922 return ebt_buf_count(state, sz);
1923 }
1924
1925 enum compat_mwt {
1926 EBT_COMPAT_MATCH,
1927 EBT_COMPAT_WATCHER,
1928 EBT_COMPAT_TARGET,
1929 };
1930
1931 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1932 enum compat_mwt compat_mwt,
1933 struct ebt_entries_buf_state *state,
1934 const unsigned char *base)
1935 {
1936 char name[EBT_FUNCTION_MAXNAMELEN];
1937 struct xt_match *match;
1938 struct xt_target *wt;
1939 void *dst = NULL;
1940 int off, pad = 0;
1941 unsigned int size_kern, match_size = mwt->match_size;
1942
1943 strlcpy(name, mwt->u.name, sizeof(name));
1944
1945 if (state->buf_kern_start)
1946 dst = state->buf_kern_start + state->buf_kern_offset;
1947
1948 switch (compat_mwt) {
1949 case EBT_COMPAT_MATCH:
1950 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1951 if (IS_ERR(match))
1952 return PTR_ERR(match);
1953
1954 off = ebt_compat_match_offset(match, match_size);
1955 if (dst) {
1956 if (match->compat_from_user)
1957 match->compat_from_user(dst, mwt->data);
1958 else
1959 memcpy(dst, mwt->data, match_size);
1960 }
1961
1962 size_kern = match->matchsize;
1963 if (unlikely(size_kern == -1))
1964 size_kern = match_size;
1965 module_put(match->me);
1966 break;
1967 case EBT_COMPAT_WATCHER: /* fallthrough */
1968 case EBT_COMPAT_TARGET:
1969 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1970 if (IS_ERR(wt))
1971 return PTR_ERR(wt);
1972 off = xt_compat_target_offset(wt);
1973
1974 if (dst) {
1975 if (wt->compat_from_user)
1976 wt->compat_from_user(dst, mwt->data);
1977 else
1978 memcpy(dst, mwt->data, match_size);
1979 }
1980
1981 size_kern = wt->targetsize;
1982 module_put(wt->me);
1983 break;
1984
1985 default:
1986 return -EINVAL;
1987 }
1988
1989 state->buf_kern_offset += match_size + off;
1990 state->buf_user_offset += match_size;
1991 pad = XT_ALIGN(size_kern) - size_kern;
1992
1993 if (pad > 0 && dst) {
1994 BUG_ON(state->buf_kern_len <= pad);
1995 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1996 memset(dst + size_kern, 0, pad);
1997 }
1998 return off + match_size;
1999 }
2000
2001 /* return size of all matches, watchers or target, including necessary
2002 * alignment and padding.
2003 */
2004 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
2005 unsigned int size_left, enum compat_mwt type,
2006 struct ebt_entries_buf_state *state, const void *base)
2007 {
2008 int growth = 0;
2009 char *buf;
2010
2011 if (size_left == 0)
2012 return 0;
2013
2014 buf = (char *) match32;
2015
2016 while (size_left >= sizeof(*match32)) {
2017 struct ebt_entry_match *match_kern;
2018 int ret;
2019
2020 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2021 if (match_kern) {
2022 char *tmp;
2023 tmp = state->buf_kern_start + state->buf_kern_offset;
2024 match_kern = (struct ebt_entry_match *) tmp;
2025 }
2026 ret = ebt_buf_add(state, buf, sizeof(*match32));
2027 if (ret < 0)
2028 return ret;
2029 size_left -= sizeof(*match32);
2030
2031 /* add padding before match->data (if any) */
2032 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2033 if (ret < 0)
2034 return ret;
2035
2036 if (match32->match_size > size_left)
2037 return -EINVAL;
2038
2039 size_left -= match32->match_size;
2040
2041 ret = compat_mtw_from_user(match32, type, state, base);
2042 if (ret < 0)
2043 return ret;
2044
2045 BUG_ON(ret < match32->match_size);
2046 growth += ret - match32->match_size;
2047 growth += ebt_compat_entry_padsize();
2048
2049 buf += sizeof(*match32);
2050 buf += match32->match_size;
2051
2052 if (match_kern)
2053 match_kern->match_size = ret;
2054
2055 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2056 match32 = (struct compat_ebt_entry_mwt *) buf;
2057 }
2058
2059 return growth;
2060 }
2061
2062 /* called for all ebt_entry structures. */
2063 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2064 unsigned int *total,
2065 struct ebt_entries_buf_state *state)
2066 {
2067 unsigned int i, j, startoff, new_offset = 0;
2068 /* stores match/watchers/targets & offset of next struct ebt_entry: */
2069 unsigned int offsets[4];
2070 unsigned int *offsets_update = NULL;
2071 int ret;
2072 char *buf_start;
2073
2074 if (*total < sizeof(struct ebt_entries))
2075 return -EINVAL;
2076
2077 if (!entry->bitmask) {
2078 *total -= sizeof(struct ebt_entries);
2079 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2080 }
2081 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2082 return -EINVAL;
2083
2084 startoff = state->buf_user_offset;
2085 /* pull in most part of ebt_entry, it does not need to be changed. */
2086 ret = ebt_buf_add(state, entry,
2087 offsetof(struct ebt_entry, watchers_offset));
2088 if (ret < 0)
2089 return ret;
2090
2091 offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2092 memcpy(&offsets[1], &entry->watchers_offset,
2093 sizeof(offsets) - sizeof(offsets[0]));
2094
2095 if (state->buf_kern_start) {
2096 buf_start = state->buf_kern_start + state->buf_kern_offset;
2097 offsets_update = (unsigned int *) buf_start;
2098 }
2099 ret = ebt_buf_add(state, &offsets[1],
2100 sizeof(offsets) - sizeof(offsets[0]));
2101 if (ret < 0)
2102 return ret;
2103 buf_start = (char *) entry;
2104 /* 0: matches offset, always follows ebt_entry.
2105 * 1: watchers offset, from ebt_entry structure
2106 * 2: target offset, from ebt_entry structure
2107 * 3: next ebt_entry offset, from ebt_entry structure
2108 *
2109 * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2110 */
2111 for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2112 struct compat_ebt_entry_mwt *match32;
2113 unsigned int size;
2114 char *buf = buf_start;
2115
2116 buf = buf_start + offsets[i];
2117 if (offsets[i] > offsets[j])
2118 return -EINVAL;
2119
2120 match32 = (struct compat_ebt_entry_mwt *) buf;
2121 size = offsets[j] - offsets[i];
2122 ret = ebt_size_mwt(match32, size, i, state, base);
2123 if (ret < 0)
2124 return ret;
2125 new_offset += ret;
2126 if (offsets_update && new_offset) {
2127 pr_debug("change offset %d to %d\n",
2128 offsets_update[i], offsets[j] + new_offset);
2129 offsets_update[i] = offsets[j] + new_offset;
2130 }
2131 }
2132
2133 if (state->buf_kern_start == NULL) {
2134 unsigned int offset = buf_start - (char *) base;
2135
2136 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2137 if (ret < 0)
2138 return ret;
2139 }
2140
2141 startoff = state->buf_user_offset - startoff;
2142
2143 BUG_ON(*total < startoff);
2144 *total -= startoff;
2145 return 0;
2146 }
2147
2148 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2149 * It might need more memory when copied to a 64 bit kernel in case
2150 * userspace is 32-bit. So, first task: find out how much memory is needed.
2151 *
2152 * Called before validation is performed.
2153 */
2154 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2155 struct ebt_entries_buf_state *state)
2156 {
2157 unsigned int size_remaining = size_user;
2158 int ret;
2159
2160 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2161 &size_remaining, state);
2162 if (ret < 0)
2163 return ret;
2164
2165 WARN_ON(size_remaining);
2166 return state->buf_kern_offset;
2167 }
2168
2169
2170 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2171 void __user *user, unsigned int len)
2172 {
2173 struct compat_ebt_replace tmp;
2174 int i;
2175
2176 if (len < sizeof(tmp))
2177 return -EINVAL;
2178
2179 if (copy_from_user(&tmp, user, sizeof(tmp)))
2180 return -EFAULT;
2181
2182 if (len != sizeof(tmp) + tmp.entries_size)
2183 return -EINVAL;
2184
2185 if (tmp.entries_size == 0)
2186 return -EINVAL;
2187
2188 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2189 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2190 return -ENOMEM;
2191 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2192 return -ENOMEM;
2193
2194 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2195
2196 /* starting with hook_entry, 32 vs. 64 bit structures are different */
2197 for (i = 0; i < NF_BR_NUMHOOKS; i++)
2198 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2199
2200 repl->num_counters = tmp.num_counters;
2201 repl->counters = compat_ptr(tmp.counters);
2202 repl->entries = compat_ptr(tmp.entries);
2203 return 0;
2204 }
2205
2206 static int compat_do_replace(struct net *net, void __user *user,
2207 unsigned int len)
2208 {
2209 int ret, i, countersize, size64;
2210 struct ebt_table_info *newinfo;
2211 struct ebt_replace tmp;
2212 struct ebt_entries_buf_state state;
2213 void *entries_tmp;
2214
2215 ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2216 if (ret) {
2217 /* try real handler in case userland supplied needed padding */
2218 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2219 ret = 0;
2220 return ret;
2221 }
2222
2223 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2224 newinfo = vmalloc(sizeof(*newinfo) + countersize);
2225 if (!newinfo)
2226 return -ENOMEM;
2227
2228 if (countersize)
2229 memset(newinfo->counters, 0, countersize);
2230
2231 memset(&state, 0, sizeof(state));
2232
2233 newinfo->entries = vmalloc(tmp.entries_size);
2234 if (!newinfo->entries) {
2235 ret = -ENOMEM;
2236 goto free_newinfo;
2237 }
2238 if (copy_from_user(
2239 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2240 ret = -EFAULT;
2241 goto free_entries;
2242 }
2243
2244 entries_tmp = newinfo->entries;
2245
2246 xt_compat_lock(NFPROTO_BRIDGE);
2247
2248 xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2249 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2250 if (ret < 0)
2251 goto out_unlock;
2252
2253 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2254 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2255 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2256
2257 size64 = ret;
2258 newinfo->entries = vmalloc(size64);
2259 if (!newinfo->entries) {
2260 vfree(entries_tmp);
2261 ret = -ENOMEM;
2262 goto out_unlock;
2263 }
2264
2265 memset(&state, 0, sizeof(state));
2266 state.buf_kern_start = newinfo->entries;
2267 state.buf_kern_len = size64;
2268
2269 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2270 BUG_ON(ret < 0); /* parses same data again */
2271
2272 vfree(entries_tmp);
2273 tmp.entries_size = size64;
2274
2275 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2276 char __user *usrptr;
2277 if (tmp.hook_entry[i]) {
2278 unsigned int delta;
2279 usrptr = (char __user *) tmp.hook_entry[i];
2280 delta = usrptr - tmp.entries;
2281 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2282 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2283 }
2284 }
2285
2286 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2287 xt_compat_unlock(NFPROTO_BRIDGE);
2288
2289 ret = do_replace_finish(net, &tmp, newinfo);
2290 if (ret == 0)
2291 return ret;
2292 free_entries:
2293 vfree(newinfo->entries);
2294 free_newinfo:
2295 vfree(newinfo);
2296 return ret;
2297 out_unlock:
2298 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2299 xt_compat_unlock(NFPROTO_BRIDGE);
2300 goto free_entries;
2301 }
2302
2303 static int compat_update_counters(struct net *net, void __user *user,
2304 unsigned int len)
2305 {
2306 struct compat_ebt_replace hlp;
2307
2308 if (copy_from_user(&hlp, user, sizeof(hlp)))
2309 return -EFAULT;
2310
2311 /* try real handler in case userland supplied needed padding */
2312 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2313 return update_counters(net, user, len);
2314
2315 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2316 hlp.num_counters, user, len);
2317 }
2318
2319 static int compat_do_ebt_set_ctl(struct sock *sk,
2320 int cmd, void __user *user, unsigned int len)
2321 {
2322 int ret;
2323 struct net *net = sock_net(sk);
2324
2325 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2326 return -EPERM;
2327
2328 switch (cmd) {
2329 case EBT_SO_SET_ENTRIES:
2330 ret = compat_do_replace(net, user, len);
2331 break;
2332 case EBT_SO_SET_COUNTERS:
2333 ret = compat_update_counters(net, user, len);
2334 break;
2335 default:
2336 ret = -EINVAL;
2337 }
2338 return ret;
2339 }
2340
2341 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2342 void __user *user, int *len)
2343 {
2344 int ret;
2345 struct compat_ebt_replace tmp;
2346 struct ebt_table *t;
2347 struct net *net = sock_net(sk);
2348
2349 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2350 return -EPERM;
2351
2352 /* try real handler in case userland supplied needed padding */
2353 if ((cmd == EBT_SO_GET_INFO ||
2354 cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2355 return do_ebt_get_ctl(sk, cmd, user, len);
2356
2357 if (copy_from_user(&tmp, user, sizeof(tmp)))
2358 return -EFAULT;
2359
2360 tmp.name[sizeof(tmp.name) - 1] = '\0';
2361
2362 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2363 if (!t)
2364 return ret;
2365
2366 xt_compat_lock(NFPROTO_BRIDGE);
2367 switch (cmd) {
2368 case EBT_SO_GET_INFO:
2369 tmp.nentries = t->private->nentries;
2370 ret = compat_table_info(t->private, &tmp);
2371 if (ret)
2372 goto out;
2373 tmp.valid_hooks = t->valid_hooks;
2374
2375 if (copy_to_user(user, &tmp, *len) != 0) {
2376 ret = -EFAULT;
2377 break;
2378 }
2379 ret = 0;
2380 break;
2381 case EBT_SO_GET_INIT_INFO:
2382 tmp.nentries = t->table->nentries;
2383 tmp.entries_size = t->table->entries_size;
2384 tmp.valid_hooks = t->table->valid_hooks;
2385
2386 if (copy_to_user(user, &tmp, *len) != 0) {
2387 ret = -EFAULT;
2388 break;
2389 }
2390 ret = 0;
2391 break;
2392 case EBT_SO_GET_ENTRIES:
2393 case EBT_SO_GET_INIT_ENTRIES:
2394 /* try real handler first in case of userland-side padding.
2395 * in case we are dealing with an 'ordinary' 32 bit binary
2396 * without 64bit compatibility padding, this will fail right
2397 * after copy_from_user when the *len argument is validated.
2398 *
2399 * the compat_ variant needs to do one pass over the kernel
2400 * data set to adjust for size differences before it the check.
2401 */
2402 if (copy_everything_to_user(t, user, len, cmd) == 0)
2403 ret = 0;
2404 else
2405 ret = compat_copy_everything_to_user(t, user, len, cmd);
2406 break;
2407 default:
2408 ret = -EINVAL;
2409 }
2410 out:
2411 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2412 xt_compat_unlock(NFPROTO_BRIDGE);
2413 mutex_unlock(&ebt_mutex);
2414 return ret;
2415 }
2416 #endif
2417
2418 static struct nf_sockopt_ops ebt_sockopts = {
2419 .pf = PF_INET,
2420 .set_optmin = EBT_BASE_CTL,
2421 .set_optmax = EBT_SO_SET_MAX + 1,
2422 .set = do_ebt_set_ctl,
2423 #ifdef CONFIG_COMPAT
2424 .compat_set = compat_do_ebt_set_ctl,
2425 #endif
2426 .get_optmin = EBT_BASE_CTL,
2427 .get_optmax = EBT_SO_GET_MAX + 1,
2428 .get = do_ebt_get_ctl,
2429 #ifdef CONFIG_COMPAT
2430 .compat_get = compat_do_ebt_get_ctl,
2431 #endif
2432 .owner = THIS_MODULE,
2433 };
2434
2435 static int __init ebtables_init(void)
2436 {
2437 int ret;
2438
2439 ret = xt_register_target(&ebt_standard_target);
2440 if (ret < 0)
2441 return ret;
2442 ret = nf_register_sockopt(&ebt_sockopts);
2443 if (ret < 0) {
2444 xt_unregister_target(&ebt_standard_target);
2445 return ret;
2446 }
2447
2448 printk(KERN_INFO "Ebtables v2.0 registered\n");
2449 return 0;
2450 }
2451
2452 static void __exit ebtables_fini(void)
2453 {
2454 nf_unregister_sockopt(&ebt_sockopts);
2455 xt_unregister_target(&ebt_standard_target);
2456 printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2457 }
2458
2459 EXPORT_SYMBOL(ebt_register_table);
2460 EXPORT_SYMBOL(ebt_unregister_table);
2461 EXPORT_SYMBOL(ebt_do_table);
2462 module_init(ebtables_init);
2463 module_exit(ebtables_fini);
2464 MODULE_LICENSE("GPL");
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