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Merge tag 'driver-core-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git...
[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 #define FWINV2(bool, invflg) ((bool) ^ !!(e->invflags & invflg))
125 /* process standard matches */
126 static inline int
127 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
128 const struct net_device *in, const struct net_device *out)
129 {
130 const struct ethhdr *h = eth_hdr(skb);
131 const struct net_bridge_port *p;
132 __be16 ethproto;
133 int verdict, i;
134
135 if (skb_vlan_tag_present(skb))
136 ethproto = htons(ETH_P_8021Q);
137 else
138 ethproto = h->h_proto;
139
140 if (e->bitmask & EBT_802_3) {
141 if (FWINV2(eth_proto_is_802_3(ethproto), EBT_IPROTO))
142 return 1;
143 } else if (!(e->bitmask & EBT_NOPROTO) &&
144 FWINV2(e->ethproto != ethproto, EBT_IPROTO))
145 return 1;
146
147 if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN))
148 return 1;
149 if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
150 return 1;
151 /* rcu_read_lock()ed by nf_hook_slow */
152 if (in && (p = br_port_get_rcu(in)) != NULL &&
153 FWINV2(ebt_dev_check(e->logical_in, p->br->dev), EBT_ILOGICALIN))
154 return 1;
155 if (out && (p = br_port_get_rcu(out)) != NULL &&
156 FWINV2(ebt_dev_check(e->logical_out, p->br->dev), EBT_ILOGICALOUT))
157 return 1;
158
159 if (e->bitmask & EBT_SOURCEMAC) {
160 verdict = 0;
161 for (i = 0; i < 6; i++)
162 verdict |= (h->h_source[i] ^ e->sourcemac[i]) &
163 e->sourcemsk[i];
164 if (FWINV2(verdict != 0, EBT_ISOURCE))
165 return 1;
166 }
167 if (e->bitmask & EBT_DESTMAC) {
168 verdict = 0;
169 for (i = 0; i < 6; i++)
170 verdict |= (h->h_dest[i] ^ e->destmac[i]) &
171 e->destmsk[i];
172 if (FWINV2(verdict != 0, EBT_IDEST))
173 return 1;
174 }
175 return 0;
176 }
177
178 static inline
179 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
180 {
181 return (void *)entry + entry->next_offset;
182 }
183
184 /* Do some firewalling */
185 unsigned int ebt_do_table(struct sk_buff *skb,
186 const struct nf_hook_state *state,
187 struct ebt_table *table)
188 {
189 unsigned int hook = state->hook;
190 int i, nentries;
191 struct ebt_entry *point;
192 struct ebt_counter *counter_base, *cb_base;
193 const struct ebt_entry_target *t;
194 int verdict, sp = 0;
195 struct ebt_chainstack *cs;
196 struct ebt_entries *chaininfo;
197 const char *base;
198 const struct ebt_table_info *private;
199 struct xt_action_param acpar;
200
201 acpar.family = NFPROTO_BRIDGE;
202 acpar.net = state->net;
203 acpar.in = state->in;
204 acpar.out = state->out;
205 acpar.hotdrop = false;
206 acpar.hooknum = hook;
207
208 read_lock_bh(&table->lock);
209 private = table->private;
210 cb_base = COUNTER_BASE(private->counters, private->nentries,
211 smp_processor_id());
212 if (private->chainstack)
213 cs = private->chainstack[smp_processor_id()];
214 else
215 cs = NULL;
216 chaininfo = private->hook_entry[hook];
217 nentries = private->hook_entry[hook]->nentries;
218 point = (struct ebt_entry *)(private->hook_entry[hook]->data);
219 counter_base = cb_base + private->hook_entry[hook]->counter_offset;
220 /* base for chain jumps */
221 base = private->entries;
222 i = 0;
223 while (i < nentries) {
224 if (ebt_basic_match(point, skb, state->in, state->out))
225 goto letscontinue;
226
227 if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
228 goto letscontinue;
229 if (acpar.hotdrop) {
230 read_unlock_bh(&table->lock);
231 return NF_DROP;
232 }
233
234 /* increase counter */
235 (*(counter_base + i)).pcnt++;
236 (*(counter_base + i)).bcnt += skb->len;
237
238 /* these should only watch: not modify, nor tell us
239 * what to do with the packet
240 */
241 EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
242
243 t = (struct ebt_entry_target *)
244 (((char *)point) + point->target_offset);
245 /* standard target */
246 if (!t->u.target->target)
247 verdict = ((struct ebt_standard_target *)t)->verdict;
248 else {
249 acpar.target = t->u.target;
250 acpar.targinfo = t->data;
251 verdict = t->u.target->target(skb, &acpar);
252 }
253 if (verdict == EBT_ACCEPT) {
254 read_unlock_bh(&table->lock);
255 return NF_ACCEPT;
256 }
257 if (verdict == EBT_DROP) {
258 read_unlock_bh(&table->lock);
259 return NF_DROP;
260 }
261 if (verdict == EBT_RETURN) {
262 letsreturn:
263 #ifdef CONFIG_NETFILTER_DEBUG
264 if (sp == 0) {
265 BUGPRINT("RETURN on base chain");
266 /* act like this is EBT_CONTINUE */
267 goto letscontinue;
268 }
269 #endif
270 sp--;
271 /* put all the local variables right */
272 i = cs[sp].n;
273 chaininfo = cs[sp].chaininfo;
274 nentries = chaininfo->nentries;
275 point = cs[sp].e;
276 counter_base = cb_base +
277 chaininfo->counter_offset;
278 continue;
279 }
280 if (verdict == EBT_CONTINUE)
281 goto letscontinue;
282 #ifdef CONFIG_NETFILTER_DEBUG
283 if (verdict < 0) {
284 BUGPRINT("bogus standard verdict\n");
285 read_unlock_bh(&table->lock);
286 return NF_DROP;
287 }
288 #endif
289 /* jump to a udc */
290 cs[sp].n = i + 1;
291 cs[sp].chaininfo = chaininfo;
292 cs[sp].e = ebt_next_entry(point);
293 i = 0;
294 chaininfo = (struct ebt_entries *) (base + verdict);
295 #ifdef CONFIG_NETFILTER_DEBUG
296 if (chaininfo->distinguisher) {
297 BUGPRINT("jump to non-chain\n");
298 read_unlock_bh(&table->lock);
299 return NF_DROP;
300 }
301 #endif
302 nentries = chaininfo->nentries;
303 point = (struct ebt_entry *)chaininfo->data;
304 counter_base = cb_base + chaininfo->counter_offset;
305 sp++;
306 continue;
307 letscontinue:
308 point = ebt_next_entry(point);
309 i++;
310 }
311
312 /* I actually like this :) */
313 if (chaininfo->policy == EBT_RETURN)
314 goto letsreturn;
315 if (chaininfo->policy == EBT_ACCEPT) {
316 read_unlock_bh(&table->lock);
317 return NF_ACCEPT;
318 }
319 read_unlock_bh(&table->lock);
320 return NF_DROP;
321 }
322
323 /* If it succeeds, returns element and locks mutex */
324 static inline void *
325 find_inlist_lock_noload(struct list_head *head, const char *name, int *error,
326 struct mutex *mutex)
327 {
328 struct {
329 struct list_head list;
330 char name[EBT_FUNCTION_MAXNAMELEN];
331 } *e;
332
333 mutex_lock(mutex);
334 list_for_each_entry(e, head, list) {
335 if (strcmp(e->name, name) == 0)
336 return e;
337 }
338 *error = -ENOENT;
339 mutex_unlock(mutex);
340 return NULL;
341 }
342
343 static void *
344 find_inlist_lock(struct list_head *head, const char *name, const char *prefix,
345 int *error, struct mutex *mutex)
346 {
347 return try_then_request_module(
348 find_inlist_lock_noload(head, name, error, mutex),
349 "%s%s", prefix, name);
350 }
351
352 static inline struct ebt_table *
353 find_table_lock(struct net *net, const char *name, int *error,
354 struct mutex *mutex)
355 {
356 return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name,
357 "ebtable_", error, mutex);
358 }
359
360 static inline int
361 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
362 unsigned int *cnt)
363 {
364 const struct ebt_entry *e = par->entryinfo;
365 struct xt_match *match;
366 size_t left = ((char *)e + e->watchers_offset) - (char *)m;
367 int ret;
368
369 if (left < sizeof(struct ebt_entry_match) ||
370 left - sizeof(struct ebt_entry_match) < m->match_size)
371 return -EINVAL;
372
373 match = xt_request_find_match(NFPROTO_BRIDGE, m->u.name, 0);
374 if (IS_ERR(match))
375 return PTR_ERR(match);
376 m->u.match = match;
377
378 par->match = match;
379 par->matchinfo = m->data;
380 ret = xt_check_match(par, m->match_size,
381 e->ethproto, e->invflags & EBT_IPROTO);
382 if (ret < 0) {
383 module_put(match->me);
384 return ret;
385 }
386
387 (*cnt)++;
388 return 0;
389 }
390
391 static inline int
392 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
393 unsigned int *cnt)
394 {
395 const struct ebt_entry *e = par->entryinfo;
396 struct xt_target *watcher;
397 size_t left = ((char *)e + e->target_offset) - (char *)w;
398 int ret;
399
400 if (left < sizeof(struct ebt_entry_watcher) ||
401 left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
402 return -EINVAL;
403
404 watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
405 if (IS_ERR(watcher))
406 return PTR_ERR(watcher);
407 w->u.watcher = watcher;
408
409 par->target = watcher;
410 par->targinfo = w->data;
411 ret = xt_check_target(par, w->watcher_size,
412 e->ethproto, e->invflags & EBT_IPROTO);
413 if (ret < 0) {
414 module_put(watcher->me);
415 return ret;
416 }
417
418 (*cnt)++;
419 return 0;
420 }
421
422 static int ebt_verify_pointers(const struct ebt_replace *repl,
423 struct ebt_table_info *newinfo)
424 {
425 unsigned int limit = repl->entries_size;
426 unsigned int valid_hooks = repl->valid_hooks;
427 unsigned int offset = 0;
428 int i;
429
430 for (i = 0; i < NF_BR_NUMHOOKS; i++)
431 newinfo->hook_entry[i] = NULL;
432
433 newinfo->entries_size = repl->entries_size;
434 newinfo->nentries = repl->nentries;
435
436 while (offset < limit) {
437 size_t left = limit - offset;
438 struct ebt_entry *e = (void *)newinfo->entries + offset;
439
440 if (left < sizeof(unsigned int))
441 break;
442
443 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
444 if ((valid_hooks & (1 << i)) == 0)
445 continue;
446 if ((char __user *)repl->hook_entry[i] ==
447 repl->entries + offset)
448 break;
449 }
450
451 if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
452 if (e->bitmask != 0) {
453 /* we make userspace set this right,
454 * so there is no misunderstanding
455 */
456 BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set "
457 "in distinguisher\n");
458 return -EINVAL;
459 }
460 if (i != NF_BR_NUMHOOKS)
461 newinfo->hook_entry[i] = (struct ebt_entries *)e;
462 if (left < sizeof(struct ebt_entries))
463 break;
464 offset += sizeof(struct ebt_entries);
465 } else {
466 if (left < sizeof(struct ebt_entry))
467 break;
468 if (left < e->next_offset)
469 break;
470 if (e->next_offset < sizeof(struct ebt_entry))
471 return -EINVAL;
472 offset += e->next_offset;
473 }
474 }
475 if (offset != limit) {
476 BUGPRINT("entries_size too small\n");
477 return -EINVAL;
478 }
479
480 /* check if all valid hooks have a chain */
481 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
482 if (!newinfo->hook_entry[i] &&
483 (valid_hooks & (1 << i))) {
484 BUGPRINT("Valid hook without chain\n");
485 return -EINVAL;
486 }
487 }
488 return 0;
489 }
490
491 /* this one is very careful, as it is the first function
492 * to parse the userspace data
493 */
494 static inline int
495 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
496 const struct ebt_table_info *newinfo,
497 unsigned int *n, unsigned int *cnt,
498 unsigned int *totalcnt, unsigned int *udc_cnt)
499 {
500 int i;
501
502 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
503 if ((void *)e == (void *)newinfo->hook_entry[i])
504 break;
505 }
506 /* beginning of a new chain
507 * if i == NF_BR_NUMHOOKS it must be a user defined chain
508 */
509 if (i != NF_BR_NUMHOOKS || !e->bitmask) {
510 /* this checks if the previous chain has as many entries
511 * as it said it has
512 */
513 if (*n != *cnt) {
514 BUGPRINT("nentries does not equal the nr of entries "
515 "in the chain\n");
516 return -EINVAL;
517 }
518 if (((struct ebt_entries *)e)->policy != EBT_DROP &&
519 ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
520 /* only RETURN from udc */
521 if (i != NF_BR_NUMHOOKS ||
522 ((struct ebt_entries *)e)->policy != EBT_RETURN) {
523 BUGPRINT("bad policy\n");
524 return -EINVAL;
525 }
526 }
527 if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
528 (*udc_cnt)++;
529 if (((struct ebt_entries *)e)->counter_offset != *totalcnt) {
530 BUGPRINT("counter_offset != totalcnt");
531 return -EINVAL;
532 }
533 *n = ((struct ebt_entries *)e)->nentries;
534 *cnt = 0;
535 return 0;
536 }
537 /* a plain old entry, heh */
538 if (sizeof(struct ebt_entry) > e->watchers_offset ||
539 e->watchers_offset > e->target_offset ||
540 e->target_offset >= e->next_offset) {
541 BUGPRINT("entry offsets not in right order\n");
542 return -EINVAL;
543 }
544 /* this is not checked anywhere else */
545 if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) {
546 BUGPRINT("target size too small\n");
547 return -EINVAL;
548 }
549 (*cnt)++;
550 (*totalcnt)++;
551 return 0;
552 }
553
554 struct ebt_cl_stack {
555 struct ebt_chainstack cs;
556 int from;
557 unsigned int hookmask;
558 };
559
560 /* We need these positions to check that the jumps to a different part of the
561 * entries is a jump to the beginning of a new chain.
562 */
563 static inline int
564 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
565 unsigned int *n, struct ebt_cl_stack *udc)
566 {
567 int i;
568
569 /* we're only interested in chain starts */
570 if (e->bitmask)
571 return 0;
572 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
573 if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
574 break;
575 }
576 /* only care about udc */
577 if (i != NF_BR_NUMHOOKS)
578 return 0;
579
580 udc[*n].cs.chaininfo = (struct ebt_entries *)e;
581 /* these initialisations are depended on later in check_chainloops() */
582 udc[*n].cs.n = 0;
583 udc[*n].hookmask = 0;
584
585 (*n)++;
586 return 0;
587 }
588
589 static inline int
590 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
591 {
592 struct xt_mtdtor_param par;
593
594 if (i && (*i)-- == 0)
595 return 1;
596
597 par.net = net;
598 par.match = m->u.match;
599 par.matchinfo = m->data;
600 par.family = NFPROTO_BRIDGE;
601 if (par.match->destroy != NULL)
602 par.match->destroy(&par);
603 module_put(par.match->me);
604 return 0;
605 }
606
607 static inline int
608 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
609 {
610 struct xt_tgdtor_param par;
611
612 if (i && (*i)-- == 0)
613 return 1;
614
615 par.net = net;
616 par.target = w->u.watcher;
617 par.targinfo = w->data;
618 par.family = NFPROTO_BRIDGE;
619 if (par.target->destroy != NULL)
620 par.target->destroy(&par);
621 module_put(par.target->me);
622 return 0;
623 }
624
625 static inline int
626 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
627 {
628 struct xt_tgdtor_param par;
629 struct ebt_entry_target *t;
630
631 if (e->bitmask == 0)
632 return 0;
633 /* we're done */
634 if (cnt && (*cnt)-- == 0)
635 return 1;
636 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
637 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
638 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
639
640 par.net = net;
641 par.target = t->u.target;
642 par.targinfo = t->data;
643 par.family = NFPROTO_BRIDGE;
644 if (par.target->destroy != NULL)
645 par.target->destroy(&par);
646 module_put(par.target->me);
647 return 0;
648 }
649
650 static inline int
651 ebt_check_entry(struct ebt_entry *e, struct net *net,
652 const struct ebt_table_info *newinfo,
653 const char *name, unsigned int *cnt,
654 struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
655 {
656 struct ebt_entry_target *t;
657 struct xt_target *target;
658 unsigned int i, j, hook = 0, hookmask = 0;
659 size_t gap;
660 int ret;
661 struct xt_mtchk_param mtpar;
662 struct xt_tgchk_param tgpar;
663
664 /* don't mess with the struct ebt_entries */
665 if (e->bitmask == 0)
666 return 0;
667
668 if (e->bitmask & ~EBT_F_MASK) {
669 BUGPRINT("Unknown flag for bitmask\n");
670 return -EINVAL;
671 }
672 if (e->invflags & ~EBT_INV_MASK) {
673 BUGPRINT("Unknown flag for inv bitmask\n");
674 return -EINVAL;
675 }
676 if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) {
677 BUGPRINT("NOPROTO & 802_3 not allowed\n");
678 return -EINVAL;
679 }
680 /* what hook do we belong to? */
681 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
682 if (!newinfo->hook_entry[i])
683 continue;
684 if ((char *)newinfo->hook_entry[i] < (char *)e)
685 hook = i;
686 else
687 break;
688 }
689 /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
690 * a base chain
691 */
692 if (i < NF_BR_NUMHOOKS)
693 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
694 else {
695 for (i = 0; i < udc_cnt; i++)
696 if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
697 break;
698 if (i == 0)
699 hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
700 else
701 hookmask = cl_s[i - 1].hookmask;
702 }
703 i = 0;
704
705 mtpar.net = tgpar.net = net;
706 mtpar.table = tgpar.table = name;
707 mtpar.entryinfo = tgpar.entryinfo = e;
708 mtpar.hook_mask = tgpar.hook_mask = hookmask;
709 mtpar.family = tgpar.family = NFPROTO_BRIDGE;
710 ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
711 if (ret != 0)
712 goto cleanup_matches;
713 j = 0;
714 ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
715 if (ret != 0)
716 goto cleanup_watchers;
717 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
718 gap = e->next_offset - e->target_offset;
719
720 target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
721 if (IS_ERR(target)) {
722 ret = PTR_ERR(target);
723 goto cleanup_watchers;
724 }
725
726 t->u.target = target;
727 if (t->u.target == &ebt_standard_target) {
728 if (gap < sizeof(struct ebt_standard_target)) {
729 BUGPRINT("Standard target size too big\n");
730 ret = -EFAULT;
731 goto cleanup_watchers;
732 }
733 if (((struct ebt_standard_target *)t)->verdict <
734 -NUM_STANDARD_TARGETS) {
735 BUGPRINT("Invalid standard target\n");
736 ret = -EFAULT;
737 goto cleanup_watchers;
738 }
739 } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
740 module_put(t->u.target->me);
741 ret = -EFAULT;
742 goto cleanup_watchers;
743 }
744
745 tgpar.target = target;
746 tgpar.targinfo = t->data;
747 ret = xt_check_target(&tgpar, t->target_size,
748 e->ethproto, e->invflags & EBT_IPROTO);
749 if (ret < 0) {
750 module_put(target->me);
751 goto cleanup_watchers;
752 }
753 (*cnt)++;
754 return 0;
755 cleanup_watchers:
756 EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
757 cleanup_matches:
758 EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
759 return ret;
760 }
761
762 /* checks for loops and sets the hook mask for udc
763 * the hook mask for udc tells us from which base chains the udc can be
764 * accessed. This mask is a parameter to the check() functions of the extensions
765 */
766 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
767 unsigned int udc_cnt, unsigned int hooknr, char *base)
768 {
769 int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
770 const struct ebt_entry *e = (struct ebt_entry *)chain->data;
771 const struct ebt_entry_target *t;
772
773 while (pos < nentries || chain_nr != -1) {
774 /* end of udc, go back one 'recursion' step */
775 if (pos == nentries) {
776 /* put back values of the time when this chain was called */
777 e = cl_s[chain_nr].cs.e;
778 if (cl_s[chain_nr].from != -1)
779 nentries =
780 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
781 else
782 nentries = chain->nentries;
783 pos = cl_s[chain_nr].cs.n;
784 /* make sure we won't see a loop that isn't one */
785 cl_s[chain_nr].cs.n = 0;
786 chain_nr = cl_s[chain_nr].from;
787 if (pos == nentries)
788 continue;
789 }
790 t = (struct ebt_entry_target *)
791 (((char *)e) + e->target_offset);
792 if (strcmp(t->u.name, EBT_STANDARD_TARGET))
793 goto letscontinue;
794 if (e->target_offset + sizeof(struct ebt_standard_target) >
795 e->next_offset) {
796 BUGPRINT("Standard target size too big\n");
797 return -1;
798 }
799 verdict = ((struct ebt_standard_target *)t)->verdict;
800 if (verdict >= 0) { /* jump to another chain */
801 struct ebt_entries *hlp2 =
802 (struct ebt_entries *)(base + verdict);
803 for (i = 0; i < udc_cnt; i++)
804 if (hlp2 == cl_s[i].cs.chaininfo)
805 break;
806 /* bad destination or loop */
807 if (i == udc_cnt) {
808 BUGPRINT("bad destination\n");
809 return -1;
810 }
811 if (cl_s[i].cs.n) {
812 BUGPRINT("loop\n");
813 return -1;
814 }
815 if (cl_s[i].hookmask & (1 << hooknr))
816 goto letscontinue;
817 /* this can't be 0, so the loop test is correct */
818 cl_s[i].cs.n = pos + 1;
819 pos = 0;
820 cl_s[i].cs.e = ebt_next_entry(e);
821 e = (struct ebt_entry *)(hlp2->data);
822 nentries = hlp2->nentries;
823 cl_s[i].from = chain_nr;
824 chain_nr = i;
825 /* this udc is accessible from the base chain for hooknr */
826 cl_s[i].hookmask |= (1 << hooknr);
827 continue;
828 }
829 letscontinue:
830 e = ebt_next_entry(e);
831 pos++;
832 }
833 return 0;
834 }
835
836 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
837 static int translate_table(struct net *net, const char *name,
838 struct ebt_table_info *newinfo)
839 {
840 unsigned int i, j, k, udc_cnt;
841 int ret;
842 struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
843
844 i = 0;
845 while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
846 i++;
847 if (i == NF_BR_NUMHOOKS) {
848 BUGPRINT("No valid hooks specified\n");
849 return -EINVAL;
850 }
851 if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) {
852 BUGPRINT("Chains don't start at beginning\n");
853 return -EINVAL;
854 }
855 /* make sure chains are ordered after each other in same order
856 * as their corresponding hooks
857 */
858 for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
859 if (!newinfo->hook_entry[j])
860 continue;
861 if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) {
862 BUGPRINT("Hook order must be followed\n");
863 return -EINVAL;
864 }
865 i = j;
866 }
867
868 /* do some early checkings and initialize some things */
869 i = 0; /* holds the expected nr. of entries for the chain */
870 j = 0; /* holds the up to now counted entries for the chain */
871 k = 0; /* holds the total nr. of entries, should equal
872 * newinfo->nentries afterwards
873 */
874 udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
875 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
876 ebt_check_entry_size_and_hooks, newinfo,
877 &i, &j, &k, &udc_cnt);
878
879 if (ret != 0)
880 return ret;
881
882 if (i != j) {
883 BUGPRINT("nentries does not equal the nr of entries in the "
884 "(last) chain\n");
885 return -EINVAL;
886 }
887 if (k != newinfo->nentries) {
888 BUGPRINT("Total nentries is wrong\n");
889 return -EINVAL;
890 }
891
892 /* get the location of the udc, put them in an array
893 * while we're at it, allocate the chainstack
894 */
895 if (udc_cnt) {
896 /* this will get free'd in do_replace()/ebt_register_table()
897 * if an error occurs
898 */
899 newinfo->chainstack =
900 vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
901 if (!newinfo->chainstack)
902 return -ENOMEM;
903 for_each_possible_cpu(i) {
904 newinfo->chainstack[i] =
905 vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0])));
906 if (!newinfo->chainstack[i]) {
907 while (i)
908 vfree(newinfo->chainstack[--i]);
909 vfree(newinfo->chainstack);
910 newinfo->chainstack = NULL;
911 return -ENOMEM;
912 }
913 }
914
915 cl_s = vmalloc(udc_cnt * sizeof(*cl_s));
916 if (!cl_s)
917 return -ENOMEM;
918 i = 0; /* the i'th udc */
919 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
920 ebt_get_udc_positions, newinfo, &i, cl_s);
921 /* sanity check */
922 if (i != udc_cnt) {
923 BUGPRINT("i != udc_cnt\n");
924 vfree(cl_s);
925 return -EFAULT;
926 }
927 }
928
929 /* Check for loops */
930 for (i = 0; i < NF_BR_NUMHOOKS; i++)
931 if (newinfo->hook_entry[i])
932 if (check_chainloops(newinfo->hook_entry[i],
933 cl_s, udc_cnt, i, newinfo->entries)) {
934 vfree(cl_s);
935 return -EINVAL;
936 }
937
938 /* we now know the following (along with E=mc²):
939 * - the nr of entries in each chain is right
940 * - the size of the allocated space is right
941 * - all valid hooks have a corresponding chain
942 * - there are no loops
943 * - wrong data can still be on the level of a single entry
944 * - could be there are jumps to places that are not the
945 * beginning of a chain. This can only occur in chains that
946 * are not accessible from any base chains, so we don't care.
947 */
948
949 /* used to know what we need to clean up if something goes wrong */
950 i = 0;
951 ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
952 ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
953 if (ret != 0) {
954 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
955 ebt_cleanup_entry, net, &i);
956 }
957 vfree(cl_s);
958 return ret;
959 }
960
961 /* called under write_lock */
962 static void get_counters(const struct ebt_counter *oldcounters,
963 struct ebt_counter *counters, unsigned int nentries)
964 {
965 int i, cpu;
966 struct ebt_counter *counter_base;
967
968 /* counters of cpu 0 */
969 memcpy(counters, oldcounters,
970 sizeof(struct ebt_counter) * nentries);
971
972 /* add other counters to those of cpu 0 */
973 for_each_possible_cpu(cpu) {
974 if (cpu == 0)
975 continue;
976 counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
977 for (i = 0; i < nentries; i++) {
978 counters[i].pcnt += counter_base[i].pcnt;
979 counters[i].bcnt += counter_base[i].bcnt;
980 }
981 }
982 }
983
984 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
985 struct ebt_table_info *newinfo)
986 {
987 int ret, i;
988 struct ebt_counter *counterstmp = NULL;
989 /* used to be able to unlock earlier */
990 struct ebt_table_info *table;
991 struct ebt_table *t;
992
993 /* the user wants counters back
994 * the check on the size is done later, when we have the lock
995 */
996 if (repl->num_counters) {
997 unsigned long size = repl->num_counters * sizeof(*counterstmp);
998 counterstmp = vmalloc(size);
999 if (!counterstmp)
1000 return -ENOMEM;
1001 }
1002
1003 newinfo->chainstack = NULL;
1004 ret = ebt_verify_pointers(repl, newinfo);
1005 if (ret != 0)
1006 goto free_counterstmp;
1007
1008 ret = translate_table(net, repl->name, newinfo);
1009
1010 if (ret != 0)
1011 goto free_counterstmp;
1012
1013 t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1014 if (!t) {
1015 ret = -ENOENT;
1016 goto free_iterate;
1017 }
1018
1019 /* the table doesn't like it */
1020 if (t->check && (ret = t->check(newinfo, repl->valid_hooks)))
1021 goto free_unlock;
1022
1023 if (repl->num_counters && repl->num_counters != t->private->nentries) {
1024 BUGPRINT("Wrong nr. of counters requested\n");
1025 ret = -EINVAL;
1026 goto free_unlock;
1027 }
1028
1029 /* we have the mutex lock, so no danger in reading this pointer */
1030 table = t->private;
1031 /* make sure the table can only be rmmod'ed if it contains no rules */
1032 if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1033 ret = -ENOENT;
1034 goto free_unlock;
1035 } else if (table->nentries && !newinfo->nentries)
1036 module_put(t->me);
1037 /* we need an atomic snapshot of the counters */
1038 write_lock_bh(&t->lock);
1039 if (repl->num_counters)
1040 get_counters(t->private->counters, counterstmp,
1041 t->private->nentries);
1042
1043 t->private = newinfo;
1044 write_unlock_bh(&t->lock);
1045 mutex_unlock(&ebt_mutex);
1046 /* so, a user can change the chains while having messed up her counter
1047 * allocation. Only reason why this is done is because this way the lock
1048 * is held only once, while this doesn't bring the kernel into a
1049 * dangerous state.
1050 */
1051 if (repl->num_counters &&
1052 copy_to_user(repl->counters, counterstmp,
1053 repl->num_counters * sizeof(struct ebt_counter))) {
1054 /* Silent error, can't fail, new table is already in place */
1055 net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1056 }
1057
1058 /* decrease module count and free resources */
1059 EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1060 ebt_cleanup_entry, net, NULL);
1061
1062 vfree(table->entries);
1063 if (table->chainstack) {
1064 for_each_possible_cpu(i)
1065 vfree(table->chainstack[i]);
1066 vfree(table->chainstack);
1067 }
1068 vfree(table);
1069
1070 vfree(counterstmp);
1071
1072 #ifdef CONFIG_AUDIT
1073 if (audit_enabled) {
1074 struct audit_buffer *ab;
1075
1076 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1077 AUDIT_NETFILTER_CFG);
1078 if (ab) {
1079 audit_log_format(ab, "table=%s family=%u entries=%u",
1080 repl->name, AF_BRIDGE, repl->nentries);
1081 audit_log_end(ab);
1082 }
1083 }
1084 #endif
1085 return ret;
1086
1087 free_unlock:
1088 mutex_unlock(&ebt_mutex);
1089 free_iterate:
1090 EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1091 ebt_cleanup_entry, net, NULL);
1092 free_counterstmp:
1093 vfree(counterstmp);
1094 /* can be initialized in translate_table() */
1095 if (newinfo->chainstack) {
1096 for_each_possible_cpu(i)
1097 vfree(newinfo->chainstack[i]);
1098 vfree(newinfo->chainstack);
1099 }
1100 return ret;
1101 }
1102
1103 /* replace the table */
1104 static int do_replace(struct net *net, const void __user *user,
1105 unsigned int len)
1106 {
1107 int ret, countersize;
1108 struct ebt_table_info *newinfo;
1109 struct ebt_replace tmp;
1110
1111 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1112 return -EFAULT;
1113
1114 if (len != sizeof(tmp) + tmp.entries_size) {
1115 BUGPRINT("Wrong len argument\n");
1116 return -EINVAL;
1117 }
1118
1119 if (tmp.entries_size == 0) {
1120 BUGPRINT("Entries_size never zero\n");
1121 return -EINVAL;
1122 }
1123 /* overflow check */
1124 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1125 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1126 return -ENOMEM;
1127 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1128 return -ENOMEM;
1129
1130 tmp.name[sizeof(tmp.name) - 1] = 0;
1131
1132 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1133 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1134 if (!newinfo)
1135 return -ENOMEM;
1136
1137 if (countersize)
1138 memset(newinfo->counters, 0, countersize);
1139
1140 newinfo->entries = vmalloc(tmp.entries_size);
1141 if (!newinfo->entries) {
1142 ret = -ENOMEM;
1143 goto free_newinfo;
1144 }
1145 if (copy_from_user(
1146 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1147 BUGPRINT("Couldn't copy entries from userspace\n");
1148 ret = -EFAULT;
1149 goto free_entries;
1150 }
1151
1152 ret = do_replace_finish(net, &tmp, newinfo);
1153 if (ret == 0)
1154 return ret;
1155 free_entries:
1156 vfree(newinfo->entries);
1157 free_newinfo:
1158 vfree(newinfo);
1159 return ret;
1160 }
1161
1162 struct ebt_table *
1163 ebt_register_table(struct net *net, const struct ebt_table *input_table)
1164 {
1165 struct ebt_table_info *newinfo;
1166 struct ebt_table *t, *table;
1167 struct ebt_replace_kernel *repl;
1168 int ret, i, countersize;
1169 void *p;
1170
1171 if (input_table == NULL || (repl = input_table->table) == NULL ||
1172 repl->entries == NULL || repl->entries_size == 0 ||
1173 repl->counters != NULL || input_table->private != NULL) {
1174 BUGPRINT("Bad table data for ebt_register_table!!!\n");
1175 return ERR_PTR(-EINVAL);
1176 }
1177
1178 /* Don't add one table to multiple lists. */
1179 table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1180 if (!table) {
1181 ret = -ENOMEM;
1182 goto out;
1183 }
1184
1185 countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1186 newinfo = vmalloc(sizeof(*newinfo) + countersize);
1187 ret = -ENOMEM;
1188 if (!newinfo)
1189 goto free_table;
1190
1191 p = vmalloc(repl->entries_size);
1192 if (!p)
1193 goto free_newinfo;
1194
1195 memcpy(p, repl->entries, repl->entries_size);
1196 newinfo->entries = p;
1197
1198 newinfo->entries_size = repl->entries_size;
1199 newinfo->nentries = repl->nentries;
1200
1201 if (countersize)
1202 memset(newinfo->counters, 0, countersize);
1203
1204 /* fill in newinfo and parse the entries */
1205 newinfo->chainstack = NULL;
1206 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1207 if ((repl->valid_hooks & (1 << i)) == 0)
1208 newinfo->hook_entry[i] = NULL;
1209 else
1210 newinfo->hook_entry[i] = p +
1211 ((char *)repl->hook_entry[i] - repl->entries);
1212 }
1213 ret = translate_table(net, repl->name, newinfo);
1214 if (ret != 0) {
1215 BUGPRINT("Translate_table failed\n");
1216 goto free_chainstack;
1217 }
1218
1219 if (table->check && table->check(newinfo, table->valid_hooks)) {
1220 BUGPRINT("The table doesn't like its own initial data, lol\n");
1221 ret = -EINVAL;
1222 goto free_chainstack;
1223 }
1224
1225 table->private = newinfo;
1226 rwlock_init(&table->lock);
1227 mutex_lock(&ebt_mutex);
1228 list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) {
1229 if (strcmp(t->name, table->name) == 0) {
1230 ret = -EEXIST;
1231 BUGPRINT("Table name already exists\n");
1232 goto free_unlock;
1233 }
1234 }
1235
1236 /* Hold a reference count if the chains aren't empty */
1237 if (newinfo->nentries && !try_module_get(table->me)) {
1238 ret = -ENOENT;
1239 goto free_unlock;
1240 }
1241 list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
1242 mutex_unlock(&ebt_mutex);
1243 return table;
1244 free_unlock:
1245 mutex_unlock(&ebt_mutex);
1246 free_chainstack:
1247 if (newinfo->chainstack) {
1248 for_each_possible_cpu(i)
1249 vfree(newinfo->chainstack[i]);
1250 vfree(newinfo->chainstack);
1251 }
1252 vfree(newinfo->entries);
1253 free_newinfo:
1254 vfree(newinfo);
1255 free_table:
1256 kfree(table);
1257 out:
1258 return ERR_PTR(ret);
1259 }
1260
1261 void ebt_unregister_table(struct net *net, struct ebt_table *table)
1262 {
1263 int i;
1264
1265 if (!table) {
1266 BUGPRINT("Request to unregister NULL table!!!\n");
1267 return;
1268 }
1269 mutex_lock(&ebt_mutex);
1270 list_del(&table->list);
1271 mutex_unlock(&ebt_mutex);
1272 EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1273 ebt_cleanup_entry, net, NULL);
1274 if (table->private->nentries)
1275 module_put(table->me);
1276 vfree(table->private->entries);
1277 if (table->private->chainstack) {
1278 for_each_possible_cpu(i)
1279 vfree(table->private->chainstack[i]);
1280 vfree(table->private->chainstack);
1281 }
1282 vfree(table->private);
1283 kfree(table);
1284 }
1285
1286 /* userspace just supplied us with counters */
1287 static int do_update_counters(struct net *net, const char *name,
1288 struct ebt_counter __user *counters,
1289 unsigned int num_counters,
1290 const void __user *user, unsigned int len)
1291 {
1292 int i, ret;
1293 struct ebt_counter *tmp;
1294 struct ebt_table *t;
1295
1296 if (num_counters == 0)
1297 return -EINVAL;
1298
1299 tmp = vmalloc(num_counters * sizeof(*tmp));
1300 if (!tmp)
1301 return -ENOMEM;
1302
1303 t = find_table_lock(net, name, &ret, &ebt_mutex);
1304 if (!t)
1305 goto free_tmp;
1306
1307 if (num_counters != t->private->nentries) {
1308 BUGPRINT("Wrong nr of counters\n");
1309 ret = -EINVAL;
1310 goto unlock_mutex;
1311 }
1312
1313 if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
1314 ret = -EFAULT;
1315 goto unlock_mutex;
1316 }
1317
1318 /* we want an atomic add of the counters */
1319 write_lock_bh(&t->lock);
1320
1321 /* we add to the counters of the first cpu */
1322 for (i = 0; i < num_counters; i++) {
1323 t->private->counters[i].pcnt += tmp[i].pcnt;
1324 t->private->counters[i].bcnt += tmp[i].bcnt;
1325 }
1326
1327 write_unlock_bh(&t->lock);
1328 ret = 0;
1329 unlock_mutex:
1330 mutex_unlock(&ebt_mutex);
1331 free_tmp:
1332 vfree(tmp);
1333 return ret;
1334 }
1335
1336 static int update_counters(struct net *net, const void __user *user,
1337 unsigned int len)
1338 {
1339 struct ebt_replace hlp;
1340
1341 if (copy_from_user(&hlp, user, sizeof(hlp)))
1342 return -EFAULT;
1343
1344 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1345 return -EINVAL;
1346
1347 return do_update_counters(net, hlp.name, hlp.counters,
1348 hlp.num_counters, user, len);
1349 }
1350
1351 static inline int ebt_make_matchname(const struct ebt_entry_match *m,
1352 const char *base, char __user *ubase)
1353 {
1354 char __user *hlp = ubase + ((char *)m - base);
1355 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1356
1357 /* ebtables expects 32 bytes long names but xt_match names are 29 bytes
1358 * long. Copy 29 bytes and fill remaining bytes with zeroes.
1359 */
1360 strlcpy(name, m->u.match->name, sizeof(name));
1361 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1362 return -EFAULT;
1363 return 0;
1364 }
1365
1366 static inline int ebt_make_watchername(const struct ebt_entry_watcher *w,
1367 const char *base, char __user *ubase)
1368 {
1369 char __user *hlp = ubase + ((char *)w - base);
1370 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1371
1372 strlcpy(name, w->u.watcher->name, sizeof(name));
1373 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1374 return -EFAULT;
1375 return 0;
1376 }
1377
1378 static inline int ebt_make_names(struct ebt_entry *e, const char *base,
1379 char __user *ubase)
1380 {
1381 int ret;
1382 char __user *hlp;
1383 const struct ebt_entry_target *t;
1384 char name[EBT_FUNCTION_MAXNAMELEN] = {};
1385
1386 if (e->bitmask == 0)
1387 return 0;
1388
1389 hlp = ubase + (((char *)e + e->target_offset) - base);
1390 t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
1391
1392 ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase);
1393 if (ret != 0)
1394 return ret;
1395 ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);
1396 if (ret != 0)
1397 return ret;
1398 strlcpy(name, t->u.target->name, sizeof(name));
1399 if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
1400 return -EFAULT;
1401 return 0;
1402 }
1403
1404 static int copy_counters_to_user(struct ebt_table *t,
1405 const struct ebt_counter *oldcounters,
1406 void __user *user, unsigned int num_counters,
1407 unsigned int nentries)
1408 {
1409 struct ebt_counter *counterstmp;
1410 int ret = 0;
1411
1412 /* userspace might not need the counters */
1413 if (num_counters == 0)
1414 return 0;
1415
1416 if (num_counters != nentries) {
1417 BUGPRINT("Num_counters wrong\n");
1418 return -EINVAL;
1419 }
1420
1421 counterstmp = vmalloc(nentries * sizeof(*counterstmp));
1422 if (!counterstmp)
1423 return -ENOMEM;
1424
1425 write_lock_bh(&t->lock);
1426 get_counters(oldcounters, counterstmp, nentries);
1427 write_unlock_bh(&t->lock);
1428
1429 if (copy_to_user(user, counterstmp,
1430 nentries * sizeof(struct ebt_counter)))
1431 ret = -EFAULT;
1432 vfree(counterstmp);
1433 return ret;
1434 }
1435
1436 /* called with ebt_mutex locked */
1437 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1438 const int *len, int cmd)
1439 {
1440 struct ebt_replace tmp;
1441 const struct ebt_counter *oldcounters;
1442 unsigned int entries_size, nentries;
1443 int ret;
1444 char *entries;
1445
1446 if (cmd == EBT_SO_GET_ENTRIES) {
1447 entries_size = t->private->entries_size;
1448 nentries = t->private->nentries;
1449 entries = t->private->entries;
1450 oldcounters = t->private->counters;
1451 } else {
1452 entries_size = t->table->entries_size;
1453 nentries = t->table->nentries;
1454 entries = t->table->entries;
1455 oldcounters = t->table->counters;
1456 }
1457
1458 if (copy_from_user(&tmp, user, sizeof(tmp)))
1459 return -EFAULT;
1460
1461 if (*len != sizeof(struct ebt_replace) + entries_size +
1462 (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1463 return -EINVAL;
1464
1465 if (tmp.nentries != nentries) {
1466 BUGPRINT("Nentries wrong\n");
1467 return -EINVAL;
1468 }
1469
1470 if (tmp.entries_size != entries_size) {
1471 BUGPRINT("Wrong size\n");
1472 return -EINVAL;
1473 }
1474
1475 ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1476 tmp.num_counters, nentries);
1477 if (ret)
1478 return ret;
1479
1480 if (copy_to_user(tmp.entries, entries, entries_size)) {
1481 BUGPRINT("Couldn't copy entries to userspace\n");
1482 return -EFAULT;
1483 }
1484 /* set the match/watcher/target names right */
1485 return EBT_ENTRY_ITERATE(entries, entries_size,
1486 ebt_make_names, entries, tmp.entries);
1487 }
1488
1489 static int do_ebt_set_ctl(struct sock *sk,
1490 int cmd, void __user *user, unsigned int len)
1491 {
1492 int ret;
1493 struct net *net = sock_net(sk);
1494
1495 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1496 return -EPERM;
1497
1498 switch (cmd) {
1499 case EBT_SO_SET_ENTRIES:
1500 ret = do_replace(net, user, len);
1501 break;
1502 case EBT_SO_SET_COUNTERS:
1503 ret = update_counters(net, user, len);
1504 break;
1505 default:
1506 ret = -EINVAL;
1507 }
1508 return ret;
1509 }
1510
1511 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1512 {
1513 int ret;
1514 struct ebt_replace tmp;
1515 struct ebt_table *t;
1516 struct net *net = sock_net(sk);
1517
1518 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1519 return -EPERM;
1520
1521 if (copy_from_user(&tmp, user, sizeof(tmp)))
1522 return -EFAULT;
1523
1524 tmp.name[sizeof(tmp.name) - 1] = '\0';
1525
1526 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
1527 if (!t)
1528 return ret;
1529
1530 switch (cmd) {
1531 case EBT_SO_GET_INFO:
1532 case EBT_SO_GET_INIT_INFO:
1533 if (*len != sizeof(struct ebt_replace)) {
1534 ret = -EINVAL;
1535 mutex_unlock(&ebt_mutex);
1536 break;
1537 }
1538 if (cmd == EBT_SO_GET_INFO) {
1539 tmp.nentries = t->private->nentries;
1540 tmp.entries_size = t->private->entries_size;
1541 tmp.valid_hooks = t->valid_hooks;
1542 } else {
1543 tmp.nentries = t->table->nentries;
1544 tmp.entries_size = t->table->entries_size;
1545 tmp.valid_hooks = t->table->valid_hooks;
1546 }
1547 mutex_unlock(&ebt_mutex);
1548 if (copy_to_user(user, &tmp, *len) != 0) {
1549 BUGPRINT("c2u Didn't work\n");
1550 ret = -EFAULT;
1551 break;
1552 }
1553 ret = 0;
1554 break;
1555
1556 case EBT_SO_GET_ENTRIES:
1557 case EBT_SO_GET_INIT_ENTRIES:
1558 ret = copy_everything_to_user(t, user, len, cmd);
1559 mutex_unlock(&ebt_mutex);
1560 break;
1561
1562 default:
1563 mutex_unlock(&ebt_mutex);
1564 ret = -EINVAL;
1565 }
1566
1567 return ret;
1568 }
1569
1570 #ifdef CONFIG_COMPAT
1571 /* 32 bit-userspace compatibility definitions. */
1572 struct compat_ebt_replace {
1573 char name[EBT_TABLE_MAXNAMELEN];
1574 compat_uint_t valid_hooks;
1575 compat_uint_t nentries;
1576 compat_uint_t entries_size;
1577 /* start of the chains */
1578 compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1579 /* nr of counters userspace expects back */
1580 compat_uint_t num_counters;
1581 /* where the kernel will put the old counters. */
1582 compat_uptr_t counters;
1583 compat_uptr_t entries;
1584 };
1585
1586 /* struct ebt_entry_match, _target and _watcher have same layout */
1587 struct compat_ebt_entry_mwt {
1588 union {
1589 char name[EBT_FUNCTION_MAXNAMELEN];
1590 compat_uptr_t ptr;
1591 } u;
1592 compat_uint_t match_size;
1593 compat_uint_t data[0];
1594 };
1595
1596 /* account for possible padding between match_size and ->data */
1597 static int ebt_compat_entry_padsize(void)
1598 {
1599 BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) <
1600 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)));
1601 return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) -
1602 COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt));
1603 }
1604
1605 static int ebt_compat_match_offset(const struct xt_match *match,
1606 unsigned int userlen)
1607 {
1608 /* ebt_among needs special handling. The kernel .matchsize is
1609 * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1610 * value is expected.
1611 * Example: userspace sends 4500, ebt_among.c wants 4504.
1612 */
1613 if (unlikely(match->matchsize == -1))
1614 return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1615 return xt_compat_match_offset(match);
1616 }
1617
1618 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1619 unsigned int *size)
1620 {
1621 const struct xt_match *match = m->u.match;
1622 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1623 int off = ebt_compat_match_offset(match, m->match_size);
1624 compat_uint_t msize = m->match_size - off;
1625
1626 BUG_ON(off >= m->match_size);
1627
1628 if (copy_to_user(cm->u.name, match->name,
1629 strlen(match->name) + 1) || put_user(msize, &cm->match_size))
1630 return -EFAULT;
1631
1632 if (match->compat_to_user) {
1633 if (match->compat_to_user(cm->data, m->data))
1634 return -EFAULT;
1635 } else if (copy_to_user(cm->data, m->data, msize))
1636 return -EFAULT;
1637
1638 *size -= ebt_compat_entry_padsize() + off;
1639 *dstptr = cm->data;
1640 *dstptr += msize;
1641 return 0;
1642 }
1643
1644 static int compat_target_to_user(struct ebt_entry_target *t,
1645 void __user **dstptr,
1646 unsigned int *size)
1647 {
1648 const struct xt_target *target = t->u.target;
1649 struct compat_ebt_entry_mwt __user *cm = *dstptr;
1650 int off = xt_compat_target_offset(target);
1651 compat_uint_t tsize = t->target_size - off;
1652
1653 BUG_ON(off >= t->target_size);
1654
1655 if (copy_to_user(cm->u.name, target->name,
1656 strlen(target->name) + 1) || put_user(tsize, &cm->match_size))
1657 return -EFAULT;
1658
1659 if (target->compat_to_user) {
1660 if (target->compat_to_user(cm->data, t->data))
1661 return -EFAULT;
1662 } else if (copy_to_user(cm->data, t->data, tsize))
1663 return -EFAULT;
1664
1665 *size -= ebt_compat_entry_padsize() + off;
1666 *dstptr = cm->data;
1667 *dstptr += tsize;
1668 return 0;
1669 }
1670
1671 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1672 void __user **dstptr,
1673 unsigned int *size)
1674 {
1675 return compat_target_to_user((struct ebt_entry_target *)w,
1676 dstptr, size);
1677 }
1678
1679 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1680 unsigned int *size)
1681 {
1682 struct ebt_entry_target *t;
1683 struct ebt_entry __user *ce;
1684 u32 watchers_offset, target_offset, next_offset;
1685 compat_uint_t origsize;
1686 int ret;
1687
1688 if (e->bitmask == 0) {
1689 if (*size < sizeof(struct ebt_entries))
1690 return -EINVAL;
1691 if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1692 return -EFAULT;
1693
1694 *dstptr += sizeof(struct ebt_entries);
1695 *size -= sizeof(struct ebt_entries);
1696 return 0;
1697 }
1698
1699 if (*size < sizeof(*ce))
1700 return -EINVAL;
1701
1702 ce = (struct ebt_entry __user *)*dstptr;
1703 if (copy_to_user(ce, e, sizeof(*ce)))
1704 return -EFAULT;
1705
1706 origsize = *size;
1707 *dstptr += sizeof(*ce);
1708
1709 ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1710 if (ret)
1711 return ret;
1712 watchers_offset = e->watchers_offset - (origsize - *size);
1713
1714 ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1715 if (ret)
1716 return ret;
1717 target_offset = e->target_offset - (origsize - *size);
1718
1719 t = (struct ebt_entry_target *) ((char *) e + e->target_offset);
1720
1721 ret = compat_target_to_user(t, dstptr, size);
1722 if (ret)
1723 return ret;
1724 next_offset = e->next_offset - (origsize - *size);
1725
1726 if (put_user(watchers_offset, &ce->watchers_offset) ||
1727 put_user(target_offset, &ce->target_offset) ||
1728 put_user(next_offset, &ce->next_offset))
1729 return -EFAULT;
1730
1731 *size -= sizeof(*ce);
1732 return 0;
1733 }
1734
1735 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1736 {
1737 *off += ebt_compat_match_offset(m->u.match, m->match_size);
1738 *off += ebt_compat_entry_padsize();
1739 return 0;
1740 }
1741
1742 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1743 {
1744 *off += xt_compat_target_offset(w->u.watcher);
1745 *off += ebt_compat_entry_padsize();
1746 return 0;
1747 }
1748
1749 static int compat_calc_entry(const struct ebt_entry *e,
1750 const struct ebt_table_info *info,
1751 const void *base,
1752 struct compat_ebt_replace *newinfo)
1753 {
1754 const struct ebt_entry_target *t;
1755 unsigned int entry_offset;
1756 int off, ret, i;
1757
1758 if (e->bitmask == 0)
1759 return 0;
1760
1761 off = 0;
1762 entry_offset = (void *)e - base;
1763
1764 EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1765 EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1766
1767 t = (const struct ebt_entry_target *) ((char *) e + e->target_offset);
1768
1769 off += xt_compat_target_offset(t->u.target);
1770 off += ebt_compat_entry_padsize();
1771
1772 newinfo->entries_size -= off;
1773
1774 ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1775 if (ret)
1776 return ret;
1777
1778 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1779 const void *hookptr = info->hook_entry[i];
1780 if (info->hook_entry[i] &&
1781 (e < (struct ebt_entry *)(base - hookptr))) {
1782 newinfo->hook_entry[i] -= off;
1783 pr_debug("0x%08X -> 0x%08X\n",
1784 newinfo->hook_entry[i] + off,
1785 newinfo->hook_entry[i]);
1786 }
1787 }
1788
1789 return 0;
1790 }
1791
1792
1793 static int compat_table_info(const struct ebt_table_info *info,
1794 struct compat_ebt_replace *newinfo)
1795 {
1796 unsigned int size = info->entries_size;
1797 const void *entries = info->entries;
1798
1799 newinfo->entries_size = size;
1800
1801 xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries);
1802 return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1803 entries, newinfo);
1804 }
1805
1806 static int compat_copy_everything_to_user(struct ebt_table *t,
1807 void __user *user, int *len, int cmd)
1808 {
1809 struct compat_ebt_replace repl, tmp;
1810 struct ebt_counter *oldcounters;
1811 struct ebt_table_info tinfo;
1812 int ret;
1813 void __user *pos;
1814
1815 memset(&tinfo, 0, sizeof(tinfo));
1816
1817 if (cmd == EBT_SO_GET_ENTRIES) {
1818 tinfo.entries_size = t->private->entries_size;
1819 tinfo.nentries = t->private->nentries;
1820 tinfo.entries = t->private->entries;
1821 oldcounters = t->private->counters;
1822 } else {
1823 tinfo.entries_size = t->table->entries_size;
1824 tinfo.nentries = t->table->nentries;
1825 tinfo.entries = t->table->entries;
1826 oldcounters = t->table->counters;
1827 }
1828
1829 if (copy_from_user(&tmp, user, sizeof(tmp)))
1830 return -EFAULT;
1831
1832 if (tmp.nentries != tinfo.nentries ||
1833 (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1834 return -EINVAL;
1835
1836 memcpy(&repl, &tmp, sizeof(repl));
1837 if (cmd == EBT_SO_GET_ENTRIES)
1838 ret = compat_table_info(t->private, &repl);
1839 else
1840 ret = compat_table_info(&tinfo, &repl);
1841 if (ret)
1842 return ret;
1843
1844 if (*len != sizeof(tmp) + repl.entries_size +
1845 (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1846 pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1847 *len, tinfo.entries_size, repl.entries_size);
1848 return -EINVAL;
1849 }
1850
1851 /* userspace might not need the counters */
1852 ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1853 tmp.num_counters, tinfo.nentries);
1854 if (ret)
1855 return ret;
1856
1857 pos = compat_ptr(tmp.entries);
1858 return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1859 compat_copy_entry_to_user, &pos, &tmp.entries_size);
1860 }
1861
1862 struct ebt_entries_buf_state {
1863 char *buf_kern_start; /* kernel buffer to copy (translated) data to */
1864 u32 buf_kern_len; /* total size of kernel buffer */
1865 u32 buf_kern_offset; /* amount of data copied so far */
1866 u32 buf_user_offset; /* read position in userspace buffer */
1867 };
1868
1869 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1870 {
1871 state->buf_kern_offset += sz;
1872 return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1873 }
1874
1875 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1876 void *data, unsigned int sz)
1877 {
1878 if (state->buf_kern_start == NULL)
1879 goto count_only;
1880
1881 BUG_ON(state->buf_kern_offset + sz > state->buf_kern_len);
1882
1883 memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1884
1885 count_only:
1886 state->buf_user_offset += sz;
1887 return ebt_buf_count(state, sz);
1888 }
1889
1890 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1891 {
1892 char *b = state->buf_kern_start;
1893
1894 BUG_ON(b && state->buf_kern_offset > state->buf_kern_len);
1895
1896 if (b != NULL && sz > 0)
1897 memset(b + state->buf_kern_offset, 0, sz);
1898 /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1899 return ebt_buf_count(state, sz);
1900 }
1901
1902 enum compat_mwt {
1903 EBT_COMPAT_MATCH,
1904 EBT_COMPAT_WATCHER,
1905 EBT_COMPAT_TARGET,
1906 };
1907
1908 static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt,
1909 enum compat_mwt compat_mwt,
1910 struct ebt_entries_buf_state *state,
1911 const unsigned char *base)
1912 {
1913 char name[EBT_FUNCTION_MAXNAMELEN];
1914 struct xt_match *match;
1915 struct xt_target *wt;
1916 void *dst = NULL;
1917 int off, pad = 0;
1918 unsigned int size_kern, match_size = mwt->match_size;
1919
1920 strlcpy(name, mwt->u.name, sizeof(name));
1921
1922 if (state->buf_kern_start)
1923 dst = state->buf_kern_start + state->buf_kern_offset;
1924
1925 switch (compat_mwt) {
1926 case EBT_COMPAT_MATCH:
1927 match = xt_request_find_match(NFPROTO_BRIDGE, name, 0);
1928 if (IS_ERR(match))
1929 return PTR_ERR(match);
1930
1931 off = ebt_compat_match_offset(match, match_size);
1932 if (dst) {
1933 if (match->compat_from_user)
1934 match->compat_from_user(dst, mwt->data);
1935 else
1936 memcpy(dst, mwt->data, match_size);
1937 }
1938
1939 size_kern = match->matchsize;
1940 if (unlikely(size_kern == -1))
1941 size_kern = match_size;
1942 module_put(match->me);
1943 break;
1944 case EBT_COMPAT_WATCHER: /* fallthrough */
1945 case EBT_COMPAT_TARGET:
1946 wt = xt_request_find_target(NFPROTO_BRIDGE, name, 0);
1947 if (IS_ERR(wt))
1948 return PTR_ERR(wt);
1949 off = xt_compat_target_offset(wt);
1950
1951 if (dst) {
1952 if (wt->compat_from_user)
1953 wt->compat_from_user(dst, mwt->data);
1954 else
1955 memcpy(dst, mwt->data, match_size);
1956 }
1957
1958 size_kern = wt->targetsize;
1959 module_put(wt->me);
1960 break;
1961
1962 default:
1963 return -EINVAL;
1964 }
1965
1966 state->buf_kern_offset += match_size + off;
1967 state->buf_user_offset += match_size;
1968 pad = XT_ALIGN(size_kern) - size_kern;
1969
1970 if (pad > 0 && dst) {
1971 BUG_ON(state->buf_kern_len <= pad);
1972 BUG_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad);
1973 memset(dst + size_kern, 0, pad);
1974 }
1975 return off + match_size;
1976 }
1977
1978 /* return size of all matches, watchers or target, including necessary
1979 * alignment and padding.
1980 */
1981 static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32,
1982 unsigned int size_left, enum compat_mwt type,
1983 struct ebt_entries_buf_state *state, const void *base)
1984 {
1985 int growth = 0;
1986 char *buf;
1987
1988 if (size_left == 0)
1989 return 0;
1990
1991 buf = (char *) match32;
1992
1993 while (size_left >= sizeof(*match32)) {
1994 struct ebt_entry_match *match_kern;
1995 int ret;
1996
1997 match_kern = (struct ebt_entry_match *) state->buf_kern_start;
1998 if (match_kern) {
1999 char *tmp;
2000 tmp = state->buf_kern_start + state->buf_kern_offset;
2001 match_kern = (struct ebt_entry_match *) tmp;
2002 }
2003 ret = ebt_buf_add(state, buf, sizeof(*match32));
2004 if (ret < 0)
2005 return ret;
2006 size_left -= sizeof(*match32);
2007
2008 /* add padding before match->data (if any) */
2009 ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2010 if (ret < 0)
2011 return ret;
2012
2013 if (match32->match_size > size_left)
2014 return -EINVAL;
2015
2016 size_left -= match32->match_size;
2017
2018 ret = compat_mtw_from_user(match32, type, state, base);
2019 if (ret < 0)
2020 return ret;
2021
2022 BUG_ON(ret < match32->match_size);
2023 growth += ret - match32->match_size;
2024 growth += ebt_compat_entry_padsize();
2025
2026 buf += sizeof(*match32);
2027 buf += match32->match_size;
2028
2029 if (match_kern)
2030 match_kern->match_size = ret;
2031
2032 WARN_ON(type == EBT_COMPAT_TARGET && size_left);
2033 match32 = (struct compat_ebt_entry_mwt *) buf;
2034 }
2035
2036 return growth;
2037 }
2038
2039 /* called for all ebt_entry structures. */
2040 static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
2041 unsigned int *total,
2042 struct ebt_entries_buf_state *state)
2043 {
2044 unsigned int i, j, startoff, new_offset = 0;
2045 /* stores match/watchers/targets & offset of next struct ebt_entry: */
2046 unsigned int offsets[4];
2047 unsigned int *offsets_update = NULL;
2048 int ret;
2049 char *buf_start;
2050
2051 if (*total < sizeof(struct ebt_entries))
2052 return -EINVAL;
2053
2054 if (!entry->bitmask) {
2055 *total -= sizeof(struct ebt_entries);
2056 return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2057 }
2058 if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2059 return -EINVAL;
2060
2061 startoff = state->buf_user_offset;
2062 /* pull in most part of ebt_entry, it does not need to be changed. */
2063 ret = ebt_buf_add(state, entry,
2064 offsetof(struct ebt_entry, watchers_offset));
2065 if (ret < 0)
2066 return ret;
2067
2068 offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2069 memcpy(&offsets[1], &entry->watchers_offset,
2070 sizeof(offsets) - sizeof(offsets[0]));
2071
2072 if (state->buf_kern_start) {
2073 buf_start = state->buf_kern_start + state->buf_kern_offset;
2074 offsets_update = (unsigned int *) buf_start;
2075 }
2076 ret = ebt_buf_add(state, &offsets[1],
2077 sizeof(offsets) - sizeof(offsets[0]));
2078 if (ret < 0)
2079 return ret;
2080 buf_start = (char *) entry;
2081 /* 0: matches offset, always follows ebt_entry.
2082 * 1: watchers offset, from ebt_entry structure
2083 * 2: target offset, from ebt_entry structure
2084 * 3: next ebt_entry offset, from ebt_entry structure
2085 *
2086 * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2087 */
2088 for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2089 struct compat_ebt_entry_mwt *match32;
2090 unsigned int size;
2091 char *buf = buf_start;
2092
2093 buf = buf_start + offsets[i];
2094 if (offsets[i] > offsets[j])
2095 return -EINVAL;
2096
2097 match32 = (struct compat_ebt_entry_mwt *) buf;
2098 size = offsets[j] - offsets[i];
2099 ret = ebt_size_mwt(match32, size, i, state, base);
2100 if (ret < 0)
2101 return ret;
2102 new_offset += ret;
2103 if (offsets_update && new_offset) {
2104 pr_debug("change offset %d to %d\n",
2105 offsets_update[i], offsets[j] + new_offset);
2106 offsets_update[i] = offsets[j] + new_offset;
2107 }
2108 }
2109
2110 if (state->buf_kern_start == NULL) {
2111 unsigned int offset = buf_start - (char *) base;
2112
2113 ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2114 if (ret < 0)
2115 return ret;
2116 }
2117
2118 startoff = state->buf_user_offset - startoff;
2119
2120 BUG_ON(*total < startoff);
2121 *total -= startoff;
2122 return 0;
2123 }
2124
2125 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2126 * It might need more memory when copied to a 64 bit kernel in case
2127 * userspace is 32-bit. So, first task: find out how much memory is needed.
2128 *
2129 * Called before validation is performed.
2130 */
2131 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2132 struct ebt_entries_buf_state *state)
2133 {
2134 unsigned int size_remaining = size_user;
2135 int ret;
2136
2137 ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2138 &size_remaining, state);
2139 if (ret < 0)
2140 return ret;
2141
2142 WARN_ON(size_remaining);
2143 return state->buf_kern_offset;
2144 }
2145
2146
2147 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2148 void __user *user, unsigned int len)
2149 {
2150 struct compat_ebt_replace tmp;
2151 int i;
2152
2153 if (len < sizeof(tmp))
2154 return -EINVAL;
2155
2156 if (copy_from_user(&tmp, user, sizeof(tmp)))
2157 return -EFAULT;
2158
2159 if (len != sizeof(tmp) + tmp.entries_size)
2160 return -EINVAL;
2161
2162 if (tmp.entries_size == 0)
2163 return -EINVAL;
2164
2165 if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2166 NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2167 return -ENOMEM;
2168 if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2169 return -ENOMEM;
2170
2171 memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2172
2173 /* starting with hook_entry, 32 vs. 64 bit structures are different */
2174 for (i = 0; i < NF_BR_NUMHOOKS; i++)
2175 repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2176
2177 repl->num_counters = tmp.num_counters;
2178 repl->counters = compat_ptr(tmp.counters);
2179 repl->entries = compat_ptr(tmp.entries);
2180 return 0;
2181 }
2182
2183 static int compat_do_replace(struct net *net, void __user *user,
2184 unsigned int len)
2185 {
2186 int ret, i, countersize, size64;
2187 struct ebt_table_info *newinfo;
2188 struct ebt_replace tmp;
2189 struct ebt_entries_buf_state state;
2190 void *entries_tmp;
2191
2192 ret = compat_copy_ebt_replace_from_user(&tmp, user, len);
2193 if (ret) {
2194 /* try real handler in case userland supplied needed padding */
2195 if (ret == -EINVAL && do_replace(net, user, len) == 0)
2196 ret = 0;
2197 return ret;
2198 }
2199
2200 countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2201 newinfo = vmalloc(sizeof(*newinfo) + countersize);
2202 if (!newinfo)
2203 return -ENOMEM;
2204
2205 if (countersize)
2206 memset(newinfo->counters, 0, countersize);
2207
2208 memset(&state, 0, sizeof(state));
2209
2210 newinfo->entries = vmalloc(tmp.entries_size);
2211 if (!newinfo->entries) {
2212 ret = -ENOMEM;
2213 goto free_newinfo;
2214 }
2215 if (copy_from_user(
2216 newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2217 ret = -EFAULT;
2218 goto free_entries;
2219 }
2220
2221 entries_tmp = newinfo->entries;
2222
2223 xt_compat_lock(NFPROTO_BRIDGE);
2224
2225 xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
2226 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2227 if (ret < 0)
2228 goto out_unlock;
2229
2230 pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2231 tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2232 xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2233
2234 size64 = ret;
2235 newinfo->entries = vmalloc(size64);
2236 if (!newinfo->entries) {
2237 vfree(entries_tmp);
2238 ret = -ENOMEM;
2239 goto out_unlock;
2240 }
2241
2242 memset(&state, 0, sizeof(state));
2243 state.buf_kern_start = newinfo->entries;
2244 state.buf_kern_len = size64;
2245
2246 ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2247 BUG_ON(ret < 0); /* parses same data again */
2248
2249 vfree(entries_tmp);
2250 tmp.entries_size = size64;
2251
2252 for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2253 char __user *usrptr;
2254 if (tmp.hook_entry[i]) {
2255 unsigned int delta;
2256 usrptr = (char __user *) tmp.hook_entry[i];
2257 delta = usrptr - tmp.entries;
2258 usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2259 tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2260 }
2261 }
2262
2263 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2264 xt_compat_unlock(NFPROTO_BRIDGE);
2265
2266 ret = do_replace_finish(net, &tmp, newinfo);
2267 if (ret == 0)
2268 return ret;
2269 free_entries:
2270 vfree(newinfo->entries);
2271 free_newinfo:
2272 vfree(newinfo);
2273 return ret;
2274 out_unlock:
2275 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2276 xt_compat_unlock(NFPROTO_BRIDGE);
2277 goto free_entries;
2278 }
2279
2280 static int compat_update_counters(struct net *net, void __user *user,
2281 unsigned int len)
2282 {
2283 struct compat_ebt_replace hlp;
2284
2285 if (copy_from_user(&hlp, user, sizeof(hlp)))
2286 return -EFAULT;
2287
2288 /* try real handler in case userland supplied needed padding */
2289 if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2290 return update_counters(net, user, len);
2291
2292 return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2293 hlp.num_counters, user, len);
2294 }
2295
2296 static int compat_do_ebt_set_ctl(struct sock *sk,
2297 int cmd, void __user *user, unsigned int len)
2298 {
2299 int ret;
2300 struct net *net = sock_net(sk);
2301
2302 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2303 return -EPERM;
2304
2305 switch (cmd) {
2306 case EBT_SO_SET_ENTRIES:
2307 ret = compat_do_replace(net, user, len);
2308 break;
2309 case EBT_SO_SET_COUNTERS:
2310 ret = compat_update_counters(net, user, len);
2311 break;
2312 default:
2313 ret = -EINVAL;
2314 }
2315 return ret;
2316 }
2317
2318 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2319 void __user *user, int *len)
2320 {
2321 int ret;
2322 struct compat_ebt_replace tmp;
2323 struct ebt_table *t;
2324 struct net *net = sock_net(sk);
2325
2326 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2327 return -EPERM;
2328
2329 /* try real handler in case userland supplied needed padding */
2330 if ((cmd == EBT_SO_GET_INFO ||
2331 cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp))
2332 return do_ebt_get_ctl(sk, cmd, user, len);
2333
2334 if (copy_from_user(&tmp, user, sizeof(tmp)))
2335 return -EFAULT;
2336
2337 tmp.name[sizeof(tmp.name) - 1] = '\0';
2338
2339 t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2340 if (!t)
2341 return ret;
2342
2343 xt_compat_lock(NFPROTO_BRIDGE);
2344 switch (cmd) {
2345 case EBT_SO_GET_INFO:
2346 tmp.nentries = t->private->nentries;
2347 ret = compat_table_info(t->private, &tmp);
2348 if (ret)
2349 goto out;
2350 tmp.valid_hooks = t->valid_hooks;
2351
2352 if (copy_to_user(user, &tmp, *len) != 0) {
2353 ret = -EFAULT;
2354 break;
2355 }
2356 ret = 0;
2357 break;
2358 case EBT_SO_GET_INIT_INFO:
2359 tmp.nentries = t->table->nentries;
2360 tmp.entries_size = t->table->entries_size;
2361 tmp.valid_hooks = t->table->valid_hooks;
2362
2363 if (copy_to_user(user, &tmp, *len) != 0) {
2364 ret = -EFAULT;
2365 break;
2366 }
2367 ret = 0;
2368 break;
2369 case EBT_SO_GET_ENTRIES:
2370 case EBT_SO_GET_INIT_ENTRIES:
2371 /* try real handler first in case of userland-side padding.
2372 * in case we are dealing with an 'ordinary' 32 bit binary
2373 * without 64bit compatibility padding, this will fail right
2374 * after copy_from_user when the *len argument is validated.
2375 *
2376 * the compat_ variant needs to do one pass over the kernel
2377 * data set to adjust for size differences before it the check.
2378 */
2379 if (copy_everything_to_user(t, user, len, cmd) == 0)
2380 ret = 0;
2381 else
2382 ret = compat_copy_everything_to_user(t, user, len, cmd);
2383 break;
2384 default:
2385 ret = -EINVAL;
2386 }
2387 out:
2388 xt_compat_flush_offsets(NFPROTO_BRIDGE);
2389 xt_compat_unlock(NFPROTO_BRIDGE);
2390 mutex_unlock(&ebt_mutex);
2391 return ret;
2392 }
2393 #endif
2394
2395 static struct nf_sockopt_ops ebt_sockopts = {
2396 .pf = PF_INET,
2397 .set_optmin = EBT_BASE_CTL,
2398 .set_optmax = EBT_SO_SET_MAX + 1,
2399 .set = do_ebt_set_ctl,
2400 #ifdef CONFIG_COMPAT
2401 .compat_set = compat_do_ebt_set_ctl,
2402 #endif
2403 .get_optmin = EBT_BASE_CTL,
2404 .get_optmax = EBT_SO_GET_MAX + 1,
2405 .get = do_ebt_get_ctl,
2406 #ifdef CONFIG_COMPAT
2407 .compat_get = compat_do_ebt_get_ctl,
2408 #endif
2409 .owner = THIS_MODULE,
2410 };
2411
2412 static int __init ebtables_init(void)
2413 {
2414 int ret;
2415
2416 ret = xt_register_target(&ebt_standard_target);
2417 if (ret < 0)
2418 return ret;
2419 ret = nf_register_sockopt(&ebt_sockopts);
2420 if (ret < 0) {
2421 xt_unregister_target(&ebt_standard_target);
2422 return ret;
2423 }
2424
2425 printk(KERN_INFO "Ebtables v2.0 registered\n");
2426 return 0;
2427 }
2428
2429 static void __exit ebtables_fini(void)
2430 {
2431 nf_unregister_sockopt(&ebt_sockopts);
2432 xt_unregister_target(&ebt_standard_target);
2433 printk(KERN_INFO "Ebtables v2.0 unregistered\n");
2434 }
2435
2436 EXPORT_SYMBOL(ebt_register_table);
2437 EXPORT_SYMBOL(ebt_unregister_table);
2438 EXPORT_SYMBOL(ebt_do_table);
2439 module_init(ebtables_init);
2440 module_exit(ebtables_fini);
2441 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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