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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[deliverable/linux.git] / net / netfilter / x_tables.c
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1/*
2 * x_tables core - Backend for {ip,ip6,arp}_tables
3 *
4 * Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
5 * Copyright (C) 2006-2012 Patrick McHardy <kaber@trash.net>
6 *
7 * Based on existing ip_tables code which is
8 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
9 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 *
15 */
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/socket.h>
20#include <linux/net.h>
21#include <linux/proc_fs.h>
22#include <linux/seq_file.h>
23#include <linux/string.h>
24#include <linux/vmalloc.h>
25#include <linux/mutex.h>
26#include <linux/mm.h>
27#include <linux/slab.h>
28#include <linux/audit.h>
29#include <net/net_namespace.h>
30
31#include <linux/netfilter/x_tables.h>
32#include <linux/netfilter_arp.h>
33#include <linux/netfilter_ipv4/ip_tables.h>
34#include <linux/netfilter_ipv6/ip6_tables.h>
35#include <linux/netfilter_arp/arp_tables.h>
36
37MODULE_LICENSE("GPL");
38MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
39MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
40
41#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
42
43struct compat_delta {
44 unsigned int offset; /* offset in kernel */
45 int delta; /* delta in 32bit user land */
46};
47
48struct xt_af {
49 struct mutex mutex;
50 struct list_head match;
51 struct list_head target;
52#ifdef CONFIG_COMPAT
53 struct mutex compat_mutex;
54 struct compat_delta *compat_tab;
55 unsigned int number; /* number of slots in compat_tab[] */
56 unsigned int cur; /* number of used slots in compat_tab[] */
57#endif
58};
59
60static struct xt_af *xt;
61
62static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
63 [NFPROTO_UNSPEC] = "x",
64 [NFPROTO_IPV4] = "ip",
65 [NFPROTO_ARP] = "arp",
66 [NFPROTO_BRIDGE] = "eb",
67 [NFPROTO_IPV6] = "ip6",
68};
69
70/* Allow this many total (re)entries. */
71static const unsigned int xt_jumpstack_multiplier = 2;
72
73/* Registration hooks for targets. */
74int xt_register_target(struct xt_target *target)
75{
76 u_int8_t af = target->family;
77
78 mutex_lock(&xt[af].mutex);
79 list_add(&target->list, &xt[af].target);
80 mutex_unlock(&xt[af].mutex);
81 return 0;
82}
83EXPORT_SYMBOL(xt_register_target);
84
85void
86xt_unregister_target(struct xt_target *target)
87{
88 u_int8_t af = target->family;
89
90 mutex_lock(&xt[af].mutex);
91 list_del(&target->list);
92 mutex_unlock(&xt[af].mutex);
93}
94EXPORT_SYMBOL(xt_unregister_target);
95
96int
97xt_register_targets(struct xt_target *target, unsigned int n)
98{
99 unsigned int i;
100 int err = 0;
101
102 for (i = 0; i < n; i++) {
103 err = xt_register_target(&target[i]);
104 if (err)
105 goto err;
106 }
107 return err;
108
109err:
110 if (i > 0)
111 xt_unregister_targets(target, i);
112 return err;
113}
114EXPORT_SYMBOL(xt_register_targets);
115
116void
117xt_unregister_targets(struct xt_target *target, unsigned int n)
118{
119 while (n-- > 0)
120 xt_unregister_target(&target[n]);
121}
122EXPORT_SYMBOL(xt_unregister_targets);
123
124int xt_register_match(struct xt_match *match)
125{
126 u_int8_t af = match->family;
127
128 mutex_lock(&xt[af].mutex);
129 list_add(&match->list, &xt[af].match);
130 mutex_unlock(&xt[af].mutex);
131 return 0;
132}
133EXPORT_SYMBOL(xt_register_match);
134
135void
136xt_unregister_match(struct xt_match *match)
137{
138 u_int8_t af = match->family;
139
140 mutex_lock(&xt[af].mutex);
141 list_del(&match->list);
142 mutex_unlock(&xt[af].mutex);
143}
144EXPORT_SYMBOL(xt_unregister_match);
145
146int
147xt_register_matches(struct xt_match *match, unsigned int n)
148{
149 unsigned int i;
150 int err = 0;
151
152 for (i = 0; i < n; i++) {
153 err = xt_register_match(&match[i]);
154 if (err)
155 goto err;
156 }
157 return err;
158
159err:
160 if (i > 0)
161 xt_unregister_matches(match, i);
162 return err;
163}
164EXPORT_SYMBOL(xt_register_matches);
165
166void
167xt_unregister_matches(struct xt_match *match, unsigned int n)
168{
169 while (n-- > 0)
170 xt_unregister_match(&match[n]);
171}
172EXPORT_SYMBOL(xt_unregister_matches);
173
174
175/*
176 * These are weird, but module loading must not be done with mutex
177 * held (since they will register), and we have to have a single
178 * function to use.
179 */
180
181/* Find match, grabs ref. Returns ERR_PTR() on error. */
182struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
183{
184 struct xt_match *m;
185 int err = -ENOENT;
186
187 mutex_lock(&xt[af].mutex);
188 list_for_each_entry(m, &xt[af].match, list) {
189 if (strcmp(m->name, name) == 0) {
190 if (m->revision == revision) {
191 if (try_module_get(m->me)) {
192 mutex_unlock(&xt[af].mutex);
193 return m;
194 }
195 } else
196 err = -EPROTOTYPE; /* Found something. */
197 }
198 }
199 mutex_unlock(&xt[af].mutex);
200
201 if (af != NFPROTO_UNSPEC)
202 /* Try searching again in the family-independent list */
203 return xt_find_match(NFPROTO_UNSPEC, name, revision);
204
205 return ERR_PTR(err);
206}
207EXPORT_SYMBOL(xt_find_match);
208
209struct xt_match *
210xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
211{
212 struct xt_match *match;
213
214 match = xt_find_match(nfproto, name, revision);
215 if (IS_ERR(match)) {
216 request_module("%st_%s", xt_prefix[nfproto], name);
217 match = xt_find_match(nfproto, name, revision);
218 }
219
220 return match;
221}
222EXPORT_SYMBOL_GPL(xt_request_find_match);
223
224/* Find target, grabs ref. Returns ERR_PTR() on error. */
225struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
226{
227 struct xt_target *t;
228 int err = -ENOENT;
229
230 mutex_lock(&xt[af].mutex);
231 list_for_each_entry(t, &xt[af].target, list) {
232 if (strcmp(t->name, name) == 0) {
233 if (t->revision == revision) {
234 if (try_module_get(t->me)) {
235 mutex_unlock(&xt[af].mutex);
236 return t;
237 }
238 } else
239 err = -EPROTOTYPE; /* Found something. */
240 }
241 }
242 mutex_unlock(&xt[af].mutex);
243
244 if (af != NFPROTO_UNSPEC)
245 /* Try searching again in the family-independent list */
246 return xt_find_target(NFPROTO_UNSPEC, name, revision);
247
248 return ERR_PTR(err);
249}
250EXPORT_SYMBOL(xt_find_target);
251
252struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
253{
254 struct xt_target *target;
255
256 target = xt_find_target(af, name, revision);
257 if (IS_ERR(target)) {
258 request_module("%st_%s", xt_prefix[af], name);
259 target = xt_find_target(af, name, revision);
260 }
261
262 return target;
263}
264EXPORT_SYMBOL_GPL(xt_request_find_target);
265
266static int match_revfn(u8 af, const char *name, u8 revision, int *bestp)
267{
268 const struct xt_match *m;
269 int have_rev = 0;
270
271 list_for_each_entry(m, &xt[af].match, list) {
272 if (strcmp(m->name, name) == 0) {
273 if (m->revision > *bestp)
274 *bestp = m->revision;
275 if (m->revision == revision)
276 have_rev = 1;
277 }
278 }
279
280 if (af != NFPROTO_UNSPEC && !have_rev)
281 return match_revfn(NFPROTO_UNSPEC, name, revision, bestp);
282
283 return have_rev;
284}
285
286static int target_revfn(u8 af, const char *name, u8 revision, int *bestp)
287{
288 const struct xt_target *t;
289 int have_rev = 0;
290
291 list_for_each_entry(t, &xt[af].target, list) {
292 if (strcmp(t->name, name) == 0) {
293 if (t->revision > *bestp)
294 *bestp = t->revision;
295 if (t->revision == revision)
296 have_rev = 1;
297 }
298 }
299
300 if (af != NFPROTO_UNSPEC && !have_rev)
301 return target_revfn(NFPROTO_UNSPEC, name, revision, bestp);
302
303 return have_rev;
304}
305
306/* Returns true or false (if no such extension at all) */
307int xt_find_revision(u8 af, const char *name, u8 revision, int target,
308 int *err)
309{
310 int have_rev, best = -1;
311
312 mutex_lock(&xt[af].mutex);
313 if (target == 1)
314 have_rev = target_revfn(af, name, revision, &best);
315 else
316 have_rev = match_revfn(af, name, revision, &best);
317 mutex_unlock(&xt[af].mutex);
318
319 /* Nothing at all? Return 0 to try loading module. */
320 if (best == -1) {
321 *err = -ENOENT;
322 return 0;
323 }
324
325 *err = best;
326 if (!have_rev)
327 *err = -EPROTONOSUPPORT;
328 return 1;
329}
330EXPORT_SYMBOL_GPL(xt_find_revision);
331
332static char *
333textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto)
334{
335 static const char *const inetbr_names[] = {
336 "PREROUTING", "INPUT", "FORWARD",
337 "OUTPUT", "POSTROUTING", "BROUTING",
338 };
339 static const char *const arp_names[] = {
340 "INPUT", "FORWARD", "OUTPUT",
341 };
342 const char *const *names;
343 unsigned int i, max;
344 char *p = buf;
345 bool np = false;
346 int res;
347
348 names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names;
349 max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) :
350 ARRAY_SIZE(inetbr_names);
351 *p = '\0';
352 for (i = 0; i < max; ++i) {
353 if (!(mask & (1 << i)))
354 continue;
355 res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]);
356 if (res > 0) {
357 size -= res;
358 p += res;
359 }
360 np = true;
361 }
362
363 return buf;
364}
365
366int xt_check_match(struct xt_mtchk_param *par,
367 unsigned int size, u_int8_t proto, bool inv_proto)
368{
369 int ret;
370
371 if (XT_ALIGN(par->match->matchsize) != size &&
372 par->match->matchsize != -1) {
373 /*
374 * ebt_among is exempt from centralized matchsize checking
375 * because it uses a dynamic-size data set.
376 */
377 pr_err("%s_tables: %s.%u match: invalid size "
378 "%u (kernel) != (user) %u\n",
379 xt_prefix[par->family], par->match->name,
380 par->match->revision,
381 XT_ALIGN(par->match->matchsize), size);
382 return -EINVAL;
383 }
384 if (par->match->table != NULL &&
385 strcmp(par->match->table, par->table) != 0) {
386 pr_err("%s_tables: %s match: only valid in %s table, not %s\n",
387 xt_prefix[par->family], par->match->name,
388 par->match->table, par->table);
389 return -EINVAL;
390 }
391 if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
392 char used[64], allow[64];
393
394 pr_err("%s_tables: %s match: used from hooks %s, but only "
395 "valid from %s\n",
396 xt_prefix[par->family], par->match->name,
397 textify_hooks(used, sizeof(used), par->hook_mask,
398 par->family),
399 textify_hooks(allow, sizeof(allow), par->match->hooks,
400 par->family));
401 return -EINVAL;
402 }
403 if (par->match->proto && (par->match->proto != proto || inv_proto)) {
404 pr_err("%s_tables: %s match: only valid for protocol %u\n",
405 xt_prefix[par->family], par->match->name,
406 par->match->proto);
407 return -EINVAL;
408 }
409 if (par->match->checkentry != NULL) {
410 ret = par->match->checkentry(par);
411 if (ret < 0)
412 return ret;
413 else if (ret > 0)
414 /* Flag up potential errors. */
415 return -EIO;
416 }
417 return 0;
418}
419EXPORT_SYMBOL_GPL(xt_check_match);
420
421#ifdef CONFIG_COMPAT
422int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
423{
424 struct xt_af *xp = &xt[af];
425
426 if (!xp->compat_tab) {
427 if (!xp->number)
428 return -EINVAL;
429 xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
430 if (!xp->compat_tab)
431 return -ENOMEM;
432 xp->cur = 0;
433 }
434
435 if (xp->cur >= xp->number)
436 return -EINVAL;
437
438 if (xp->cur)
439 delta += xp->compat_tab[xp->cur - 1].delta;
440 xp->compat_tab[xp->cur].offset = offset;
441 xp->compat_tab[xp->cur].delta = delta;
442 xp->cur++;
443 return 0;
444}
445EXPORT_SYMBOL_GPL(xt_compat_add_offset);
446
447void xt_compat_flush_offsets(u_int8_t af)
448{
449 if (xt[af].compat_tab) {
450 vfree(xt[af].compat_tab);
451 xt[af].compat_tab = NULL;
452 xt[af].number = 0;
453 xt[af].cur = 0;
454 }
455}
456EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
457
458int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
459{
460 struct compat_delta *tmp = xt[af].compat_tab;
461 int mid, left = 0, right = xt[af].cur - 1;
462
463 while (left <= right) {
464 mid = (left + right) >> 1;
465 if (offset > tmp[mid].offset)
466 left = mid + 1;
467 else if (offset < tmp[mid].offset)
468 right = mid - 1;
469 else
470 return mid ? tmp[mid - 1].delta : 0;
471 }
472 return left ? tmp[left - 1].delta : 0;
473}
474EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
475
476void xt_compat_init_offsets(u_int8_t af, unsigned int number)
477{
478 xt[af].number = number;
479 xt[af].cur = 0;
480}
481EXPORT_SYMBOL(xt_compat_init_offsets);
482
483int xt_compat_match_offset(const struct xt_match *match)
484{
485 u_int16_t csize = match->compatsize ? : match->matchsize;
486 return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
487}
488EXPORT_SYMBOL_GPL(xt_compat_match_offset);
489
490int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
491 unsigned int *size)
492{
493 const struct xt_match *match = m->u.kernel.match;
494 struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
495 int pad, off = xt_compat_match_offset(match);
496 u_int16_t msize = cm->u.user.match_size;
497
498 m = *dstptr;
499 memcpy(m, cm, sizeof(*cm));
500 if (match->compat_from_user)
501 match->compat_from_user(m->data, cm->data);
502 else
503 memcpy(m->data, cm->data, msize - sizeof(*cm));
504 pad = XT_ALIGN(match->matchsize) - match->matchsize;
505 if (pad > 0)
506 memset(m->data + match->matchsize, 0, pad);
507
508 msize += off;
509 m->u.user.match_size = msize;
510
511 *size += off;
512 *dstptr += msize;
513 return 0;
514}
515EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
516
517int xt_compat_match_to_user(const struct xt_entry_match *m,
518 void __user **dstptr, unsigned int *size)
519{
520 const struct xt_match *match = m->u.kernel.match;
521 struct compat_xt_entry_match __user *cm = *dstptr;
522 int off = xt_compat_match_offset(match);
523 u_int16_t msize = m->u.user.match_size - off;
524
525 if (copy_to_user(cm, m, sizeof(*cm)) ||
526 put_user(msize, &cm->u.user.match_size) ||
527 copy_to_user(cm->u.user.name, m->u.kernel.match->name,
528 strlen(m->u.kernel.match->name) + 1))
529 return -EFAULT;
530
531 if (match->compat_to_user) {
532 if (match->compat_to_user((void __user *)cm->data, m->data))
533 return -EFAULT;
534 } else {
535 if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
536 return -EFAULT;
537 }
538
539 *size -= off;
540 *dstptr += msize;
541 return 0;
542}
543EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
544#endif /* CONFIG_COMPAT */
545
546int xt_check_target(struct xt_tgchk_param *par,
547 unsigned int size, u_int8_t proto, bool inv_proto)
548{
549 int ret;
550
551 if (XT_ALIGN(par->target->targetsize) != size) {
552 pr_err("%s_tables: %s.%u target: invalid size "
553 "%u (kernel) != (user) %u\n",
554 xt_prefix[par->family], par->target->name,
555 par->target->revision,
556 XT_ALIGN(par->target->targetsize), size);
557 return -EINVAL;
558 }
559 if (par->target->table != NULL &&
560 strcmp(par->target->table, par->table) != 0) {
561 pr_err("%s_tables: %s target: only valid in %s table, not %s\n",
562 xt_prefix[par->family], par->target->name,
563 par->target->table, par->table);
564 return -EINVAL;
565 }
566 if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
567 char used[64], allow[64];
568
569 pr_err("%s_tables: %s target: used from hooks %s, but only "
570 "usable from %s\n",
571 xt_prefix[par->family], par->target->name,
572 textify_hooks(used, sizeof(used), par->hook_mask,
573 par->family),
574 textify_hooks(allow, sizeof(allow), par->target->hooks,
575 par->family));
576 return -EINVAL;
577 }
578 if (par->target->proto && (par->target->proto != proto || inv_proto)) {
579 pr_err("%s_tables: %s target: only valid for protocol %u\n",
580 xt_prefix[par->family], par->target->name,
581 par->target->proto);
582 return -EINVAL;
583 }
584 if (par->target->checkentry != NULL) {
585 ret = par->target->checkentry(par);
586 if (ret < 0)
587 return ret;
588 else if (ret > 0)
589 /* Flag up potential errors. */
590 return -EIO;
591 }
592 return 0;
593}
594EXPORT_SYMBOL_GPL(xt_check_target);
595
596#ifdef CONFIG_COMPAT
597int xt_compat_target_offset(const struct xt_target *target)
598{
599 u_int16_t csize = target->compatsize ? : target->targetsize;
600 return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
601}
602EXPORT_SYMBOL_GPL(xt_compat_target_offset);
603
604void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
605 unsigned int *size)
606{
607 const struct xt_target *target = t->u.kernel.target;
608 struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
609 int pad, off = xt_compat_target_offset(target);
610 u_int16_t tsize = ct->u.user.target_size;
611
612 t = *dstptr;
613 memcpy(t, ct, sizeof(*ct));
614 if (target->compat_from_user)
615 target->compat_from_user(t->data, ct->data);
616 else
617 memcpy(t->data, ct->data, tsize - sizeof(*ct));
618 pad = XT_ALIGN(target->targetsize) - target->targetsize;
619 if (pad > 0)
620 memset(t->data + target->targetsize, 0, pad);
621
622 tsize += off;
623 t->u.user.target_size = tsize;
624
625 *size += off;
626 *dstptr += tsize;
627}
628EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
629
630int xt_compat_target_to_user(const struct xt_entry_target *t,
631 void __user **dstptr, unsigned int *size)
632{
633 const struct xt_target *target = t->u.kernel.target;
634 struct compat_xt_entry_target __user *ct = *dstptr;
635 int off = xt_compat_target_offset(target);
636 u_int16_t tsize = t->u.user.target_size - off;
637
638 if (copy_to_user(ct, t, sizeof(*ct)) ||
639 put_user(tsize, &ct->u.user.target_size) ||
640 copy_to_user(ct->u.user.name, t->u.kernel.target->name,
641 strlen(t->u.kernel.target->name) + 1))
642 return -EFAULT;
643
644 if (target->compat_to_user) {
645 if (target->compat_to_user((void __user *)ct->data, t->data))
646 return -EFAULT;
647 } else {
648 if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
649 return -EFAULT;
650 }
651
652 *size -= off;
653 *dstptr += tsize;
654 return 0;
655}
656EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
657#endif
658
659struct xt_table_info *xt_alloc_table_info(unsigned int size)
660{
661 struct xt_table_info *newinfo;
662 int cpu;
663
664 /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
665 if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
666 return NULL;
667
668 newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
669 if (!newinfo)
670 return NULL;
671
672 newinfo->size = size;
673
674 for_each_possible_cpu(cpu) {
675 if (size <= PAGE_SIZE)
676 newinfo->entries[cpu] = kmalloc_node(size,
677 GFP_KERNEL,
678 cpu_to_node(cpu));
679 else
680 newinfo->entries[cpu] = vmalloc_node(size,
681 cpu_to_node(cpu));
682
683 if (newinfo->entries[cpu] == NULL) {
684 xt_free_table_info(newinfo);
685 return NULL;
686 }
687 }
688
689 return newinfo;
690}
691EXPORT_SYMBOL(xt_alloc_table_info);
692
693void xt_free_table_info(struct xt_table_info *info)
694{
695 int cpu;
696
697 for_each_possible_cpu(cpu)
698 kvfree(info->entries[cpu]);
699
700 if (info->jumpstack != NULL) {
701 for_each_possible_cpu(cpu)
702 kvfree(info->jumpstack[cpu]);
703 kvfree(info->jumpstack);
704 }
705
706 free_percpu(info->stackptr);
707
708 kfree(info);
709}
710EXPORT_SYMBOL(xt_free_table_info);
711
712/* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */
713struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
714 const char *name)
715{
716 struct xt_table *t;
717
718 mutex_lock(&xt[af].mutex);
719 list_for_each_entry(t, &net->xt.tables[af], list)
720 if (strcmp(t->name, name) == 0 && try_module_get(t->me))
721 return t;
722 mutex_unlock(&xt[af].mutex);
723 return NULL;
724}
725EXPORT_SYMBOL_GPL(xt_find_table_lock);
726
727void xt_table_unlock(struct xt_table *table)
728{
729 mutex_unlock(&xt[table->af].mutex);
730}
731EXPORT_SYMBOL_GPL(xt_table_unlock);
732
733#ifdef CONFIG_COMPAT
734void xt_compat_lock(u_int8_t af)
735{
736 mutex_lock(&xt[af].compat_mutex);
737}
738EXPORT_SYMBOL_GPL(xt_compat_lock);
739
740void xt_compat_unlock(u_int8_t af)
741{
742 mutex_unlock(&xt[af].compat_mutex);
743}
744EXPORT_SYMBOL_GPL(xt_compat_unlock);
745#endif
746
747DEFINE_PER_CPU(seqcount_t, xt_recseq);
748EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
749
750static int xt_jumpstack_alloc(struct xt_table_info *i)
751{
752 unsigned int size;
753 int cpu;
754
755 i->stackptr = alloc_percpu(unsigned int);
756 if (i->stackptr == NULL)
757 return -ENOMEM;
758
759 size = sizeof(void **) * nr_cpu_ids;
760 if (size > PAGE_SIZE)
761 i->jumpstack = vzalloc(size);
762 else
763 i->jumpstack = kzalloc(size, GFP_KERNEL);
764 if (i->jumpstack == NULL)
765 return -ENOMEM;
766
767 i->stacksize *= xt_jumpstack_multiplier;
768 size = sizeof(void *) * i->stacksize;
769 for_each_possible_cpu(cpu) {
770 if (size > PAGE_SIZE)
771 i->jumpstack[cpu] = vmalloc_node(size,
772 cpu_to_node(cpu));
773 else
774 i->jumpstack[cpu] = kmalloc_node(size,
775 GFP_KERNEL, cpu_to_node(cpu));
776 if (i->jumpstack[cpu] == NULL)
777 /*
778 * Freeing will be done later on by the callers. The
779 * chain is: xt_replace_table -> __do_replace ->
780 * do_replace -> xt_free_table_info.
781 */
782 return -ENOMEM;
783 }
784
785 return 0;
786}
787
788struct xt_table_info *
789xt_replace_table(struct xt_table *table,
790 unsigned int num_counters,
791 struct xt_table_info *newinfo,
792 int *error)
793{
794 struct xt_table_info *private;
795 int ret;
796
797 ret = xt_jumpstack_alloc(newinfo);
798 if (ret < 0) {
799 *error = ret;
800 return NULL;
801 }
802
803 /* Do the substitution. */
804 local_bh_disable();
805 private = table->private;
806
807 /* Check inside lock: is the old number correct? */
808 if (num_counters != private->number) {
809 pr_debug("num_counters != table->private->number (%u/%u)\n",
810 num_counters, private->number);
811 local_bh_enable();
812 *error = -EAGAIN;
813 return NULL;
814 }
815
816 newinfo->initial_entries = private->initial_entries;
817 /*
818 * Ensure contents of newinfo are visible before assigning to
819 * private.
820 */
821 smp_wmb();
822 table->private = newinfo;
823
824 /*
825 * Even though table entries have now been swapped, other CPU's
826 * may still be using the old entries. This is okay, because
827 * resynchronization happens because of the locking done
828 * during the get_counters() routine.
829 */
830 local_bh_enable();
831
832#ifdef CONFIG_AUDIT
833 if (audit_enabled) {
834 struct audit_buffer *ab;
835
836 ab = audit_log_start(current->audit_context, GFP_KERNEL,
837 AUDIT_NETFILTER_CFG);
838 if (ab) {
839 audit_log_format(ab, "table=%s family=%u entries=%u",
840 table->name, table->af,
841 private->number);
842 audit_log_end(ab);
843 }
844 }
845#endif
846
847 return private;
848}
849EXPORT_SYMBOL_GPL(xt_replace_table);
850
851struct xt_table *xt_register_table(struct net *net,
852 const struct xt_table *input_table,
853 struct xt_table_info *bootstrap,
854 struct xt_table_info *newinfo)
855{
856 int ret;
857 struct xt_table_info *private;
858 struct xt_table *t, *table;
859
860 /* Don't add one object to multiple lists. */
861 table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL);
862 if (!table) {
863 ret = -ENOMEM;
864 goto out;
865 }
866
867 mutex_lock(&xt[table->af].mutex);
868 /* Don't autoload: we'd eat our tail... */
869 list_for_each_entry(t, &net->xt.tables[table->af], list) {
870 if (strcmp(t->name, table->name) == 0) {
871 ret = -EEXIST;
872 goto unlock;
873 }
874 }
875
876 /* Simplifies replace_table code. */
877 table->private = bootstrap;
878
879 if (!xt_replace_table(table, 0, newinfo, &ret))
880 goto unlock;
881
882 private = table->private;
883 pr_debug("table->private->number = %u\n", private->number);
884
885 /* save number of initial entries */
886 private->initial_entries = private->number;
887
888 list_add(&table->list, &net->xt.tables[table->af]);
889 mutex_unlock(&xt[table->af].mutex);
890 return table;
891
892unlock:
893 mutex_unlock(&xt[table->af].mutex);
894 kfree(table);
895out:
896 return ERR_PTR(ret);
897}
898EXPORT_SYMBOL_GPL(xt_register_table);
899
900void *xt_unregister_table(struct xt_table *table)
901{
902 struct xt_table_info *private;
903
904 mutex_lock(&xt[table->af].mutex);
905 private = table->private;
906 list_del(&table->list);
907 mutex_unlock(&xt[table->af].mutex);
908 kfree(table);
909
910 return private;
911}
912EXPORT_SYMBOL_GPL(xt_unregister_table);
913
914#ifdef CONFIG_PROC_FS
915struct xt_names_priv {
916 struct seq_net_private p;
917 u_int8_t af;
918};
919static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
920{
921 struct xt_names_priv *priv = seq->private;
922 struct net *net = seq_file_net(seq);
923 u_int8_t af = priv->af;
924
925 mutex_lock(&xt[af].mutex);
926 return seq_list_start(&net->xt.tables[af], *pos);
927}
928
929static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
930{
931 struct xt_names_priv *priv = seq->private;
932 struct net *net = seq_file_net(seq);
933 u_int8_t af = priv->af;
934
935 return seq_list_next(v, &net->xt.tables[af], pos);
936}
937
938static void xt_table_seq_stop(struct seq_file *seq, void *v)
939{
940 struct xt_names_priv *priv = seq->private;
941 u_int8_t af = priv->af;
942
943 mutex_unlock(&xt[af].mutex);
944}
945
946static int xt_table_seq_show(struct seq_file *seq, void *v)
947{
948 struct xt_table *table = list_entry(v, struct xt_table, list);
949
950 if (strlen(table->name))
951 return seq_printf(seq, "%s\n", table->name);
952 else
953 return 0;
954}
955
956static const struct seq_operations xt_table_seq_ops = {
957 .start = xt_table_seq_start,
958 .next = xt_table_seq_next,
959 .stop = xt_table_seq_stop,
960 .show = xt_table_seq_show,
961};
962
963static int xt_table_open(struct inode *inode, struct file *file)
964{
965 int ret;
966 struct xt_names_priv *priv;
967
968 ret = seq_open_net(inode, file, &xt_table_seq_ops,
969 sizeof(struct xt_names_priv));
970 if (!ret) {
971 priv = ((struct seq_file *)file->private_data)->private;
972 priv->af = (unsigned long)PDE_DATA(inode);
973 }
974 return ret;
975}
976
977static const struct file_operations xt_table_ops = {
978 .owner = THIS_MODULE,
979 .open = xt_table_open,
980 .read = seq_read,
981 .llseek = seq_lseek,
982 .release = seq_release_net,
983};
984
985/*
986 * Traverse state for ip{,6}_{tables,matches} for helping crossing
987 * the multi-AF mutexes.
988 */
989struct nf_mttg_trav {
990 struct list_head *head, *curr;
991 uint8_t class, nfproto;
992};
993
994enum {
995 MTTG_TRAV_INIT,
996 MTTG_TRAV_NFP_UNSPEC,
997 MTTG_TRAV_NFP_SPEC,
998 MTTG_TRAV_DONE,
999};
1000
1001static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
1002 bool is_target)
1003{
1004 static const uint8_t next_class[] = {
1005 [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
1006 [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE,
1007 };
1008 struct nf_mttg_trav *trav = seq->private;
1009
1010 switch (trav->class) {
1011 case MTTG_TRAV_INIT:
1012 trav->class = MTTG_TRAV_NFP_UNSPEC;
1013 mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
1014 trav->head = trav->curr = is_target ?
1015 &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
1016 break;
1017 case MTTG_TRAV_NFP_UNSPEC:
1018 trav->curr = trav->curr->next;
1019 if (trav->curr != trav->head)
1020 break;
1021 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1022 mutex_lock(&xt[trav->nfproto].mutex);
1023 trav->head = trav->curr = is_target ?
1024 &xt[trav->nfproto].target : &xt[trav->nfproto].match;
1025 trav->class = next_class[trav->class];
1026 break;
1027 case MTTG_TRAV_NFP_SPEC:
1028 trav->curr = trav->curr->next;
1029 if (trav->curr != trav->head)
1030 break;
1031 /* fallthru, _stop will unlock */
1032 default:
1033 return NULL;
1034 }
1035
1036 if (ppos != NULL)
1037 ++*ppos;
1038 return trav;
1039}
1040
1041static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
1042 bool is_target)
1043{
1044 struct nf_mttg_trav *trav = seq->private;
1045 unsigned int j;
1046
1047 trav->class = MTTG_TRAV_INIT;
1048 for (j = 0; j < *pos; ++j)
1049 if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
1050 return NULL;
1051 return trav;
1052}
1053
1054static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
1055{
1056 struct nf_mttg_trav *trav = seq->private;
1057
1058 switch (trav->class) {
1059 case MTTG_TRAV_NFP_UNSPEC:
1060 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1061 break;
1062 case MTTG_TRAV_NFP_SPEC:
1063 mutex_unlock(&xt[trav->nfproto].mutex);
1064 break;
1065 }
1066}
1067
1068static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
1069{
1070 return xt_mttg_seq_start(seq, pos, false);
1071}
1072
1073static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1074{
1075 return xt_mttg_seq_next(seq, v, ppos, false);
1076}
1077
1078static int xt_match_seq_show(struct seq_file *seq, void *v)
1079{
1080 const struct nf_mttg_trav *trav = seq->private;
1081 const struct xt_match *match;
1082
1083 switch (trav->class) {
1084 case MTTG_TRAV_NFP_UNSPEC:
1085 case MTTG_TRAV_NFP_SPEC:
1086 if (trav->curr == trav->head)
1087 return 0;
1088 match = list_entry(trav->curr, struct xt_match, list);
1089 return (*match->name == '\0') ? 0 :
1090 seq_printf(seq, "%s\n", match->name);
1091 }
1092 return 0;
1093}
1094
1095static const struct seq_operations xt_match_seq_ops = {
1096 .start = xt_match_seq_start,
1097 .next = xt_match_seq_next,
1098 .stop = xt_mttg_seq_stop,
1099 .show = xt_match_seq_show,
1100};
1101
1102static int xt_match_open(struct inode *inode, struct file *file)
1103{
1104 struct seq_file *seq;
1105 struct nf_mttg_trav *trav;
1106 int ret;
1107
1108 trav = kmalloc(sizeof(*trav), GFP_KERNEL);
1109 if (trav == NULL)
1110 return -ENOMEM;
1111
1112 ret = seq_open(file, &xt_match_seq_ops);
1113 if (ret < 0) {
1114 kfree(trav);
1115 return ret;
1116 }
1117
1118 seq = file->private_data;
1119 seq->private = trav;
1120 trav->nfproto = (unsigned long)PDE_DATA(inode);
1121 return 0;
1122}
1123
1124static const struct file_operations xt_match_ops = {
1125 .owner = THIS_MODULE,
1126 .open = xt_match_open,
1127 .read = seq_read,
1128 .llseek = seq_lseek,
1129 .release = seq_release_private,
1130};
1131
1132static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
1133{
1134 return xt_mttg_seq_start(seq, pos, true);
1135}
1136
1137static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1138{
1139 return xt_mttg_seq_next(seq, v, ppos, true);
1140}
1141
1142static int xt_target_seq_show(struct seq_file *seq, void *v)
1143{
1144 const struct nf_mttg_trav *trav = seq->private;
1145 const struct xt_target *target;
1146
1147 switch (trav->class) {
1148 case MTTG_TRAV_NFP_UNSPEC:
1149 case MTTG_TRAV_NFP_SPEC:
1150 if (trav->curr == trav->head)
1151 return 0;
1152 target = list_entry(trav->curr, struct xt_target, list);
1153 return (*target->name == '\0') ? 0 :
1154 seq_printf(seq, "%s\n", target->name);
1155 }
1156 return 0;
1157}
1158
1159static const struct seq_operations xt_target_seq_ops = {
1160 .start = xt_target_seq_start,
1161 .next = xt_target_seq_next,
1162 .stop = xt_mttg_seq_stop,
1163 .show = xt_target_seq_show,
1164};
1165
1166static int xt_target_open(struct inode *inode, struct file *file)
1167{
1168 struct seq_file *seq;
1169 struct nf_mttg_trav *trav;
1170 int ret;
1171
1172 trav = kmalloc(sizeof(*trav), GFP_KERNEL);
1173 if (trav == NULL)
1174 return -ENOMEM;
1175
1176 ret = seq_open(file, &xt_target_seq_ops);
1177 if (ret < 0) {
1178 kfree(trav);
1179 return ret;
1180 }
1181
1182 seq = file->private_data;
1183 seq->private = trav;
1184 trav->nfproto = (unsigned long)PDE_DATA(inode);
1185 return 0;
1186}
1187
1188static const struct file_operations xt_target_ops = {
1189 .owner = THIS_MODULE,
1190 .open = xt_target_open,
1191 .read = seq_read,
1192 .llseek = seq_lseek,
1193 .release = seq_release_private,
1194};
1195
1196#define FORMAT_TABLES "_tables_names"
1197#define FORMAT_MATCHES "_tables_matches"
1198#define FORMAT_TARGETS "_tables_targets"
1199
1200#endif /* CONFIG_PROC_FS */
1201
1202/**
1203 * xt_hook_link - set up hooks for a new table
1204 * @table: table with metadata needed to set up hooks
1205 * @fn: Hook function
1206 *
1207 * This function will take care of creating and registering the necessary
1208 * Netfilter hooks for XT tables.
1209 */
1210struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn)
1211{
1212 unsigned int hook_mask = table->valid_hooks;
1213 uint8_t i, num_hooks = hweight32(hook_mask);
1214 uint8_t hooknum;
1215 struct nf_hook_ops *ops;
1216 int ret;
1217
1218 ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
1219 if (ops == NULL)
1220 return ERR_PTR(-ENOMEM);
1221
1222 for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0;
1223 hook_mask >>= 1, ++hooknum) {
1224 if (!(hook_mask & 1))
1225 continue;
1226 ops[i].hook = fn;
1227 ops[i].owner = table->me;
1228 ops[i].pf = table->af;
1229 ops[i].hooknum = hooknum;
1230 ops[i].priority = table->priority;
1231 ++i;
1232 }
1233
1234 ret = nf_register_hooks(ops, num_hooks);
1235 if (ret < 0) {
1236 kfree(ops);
1237 return ERR_PTR(ret);
1238 }
1239
1240 return ops;
1241}
1242EXPORT_SYMBOL_GPL(xt_hook_link);
1243
1244/**
1245 * xt_hook_unlink - remove hooks for a table
1246 * @ops: nf_hook_ops array as returned by nf_hook_link
1247 * @hook_mask: the very same mask that was passed to nf_hook_link
1248 */
1249void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops)
1250{
1251 nf_unregister_hooks(ops, hweight32(table->valid_hooks));
1252 kfree(ops);
1253}
1254EXPORT_SYMBOL_GPL(xt_hook_unlink);
1255
1256int xt_proto_init(struct net *net, u_int8_t af)
1257{
1258#ifdef CONFIG_PROC_FS
1259 char buf[XT_FUNCTION_MAXNAMELEN];
1260 struct proc_dir_entry *proc;
1261#endif
1262
1263 if (af >= ARRAY_SIZE(xt_prefix))
1264 return -EINVAL;
1265
1266
1267#ifdef CONFIG_PROC_FS
1268 strlcpy(buf, xt_prefix[af], sizeof(buf));
1269 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1270 proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops,
1271 (void *)(unsigned long)af);
1272 if (!proc)
1273 goto out;
1274
1275 strlcpy(buf, xt_prefix[af], sizeof(buf));
1276 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1277 proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops,
1278 (void *)(unsigned long)af);
1279 if (!proc)
1280 goto out_remove_tables;
1281
1282 strlcpy(buf, xt_prefix[af], sizeof(buf));
1283 strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1284 proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops,
1285 (void *)(unsigned long)af);
1286 if (!proc)
1287 goto out_remove_matches;
1288#endif
1289
1290 return 0;
1291
1292#ifdef CONFIG_PROC_FS
1293out_remove_matches:
1294 strlcpy(buf, xt_prefix[af], sizeof(buf));
1295 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1296 remove_proc_entry(buf, net->proc_net);
1297
1298out_remove_tables:
1299 strlcpy(buf, xt_prefix[af], sizeof(buf));
1300 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1301 remove_proc_entry(buf, net->proc_net);
1302out:
1303 return -1;
1304#endif
1305}
1306EXPORT_SYMBOL_GPL(xt_proto_init);
1307
1308void xt_proto_fini(struct net *net, u_int8_t af)
1309{
1310#ifdef CONFIG_PROC_FS
1311 char buf[XT_FUNCTION_MAXNAMELEN];
1312
1313 strlcpy(buf, xt_prefix[af], sizeof(buf));
1314 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1315 remove_proc_entry(buf, net->proc_net);
1316
1317 strlcpy(buf, xt_prefix[af], sizeof(buf));
1318 strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1319 remove_proc_entry(buf, net->proc_net);
1320
1321 strlcpy(buf, xt_prefix[af], sizeof(buf));
1322 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1323 remove_proc_entry(buf, net->proc_net);
1324#endif /*CONFIG_PROC_FS*/
1325}
1326EXPORT_SYMBOL_GPL(xt_proto_fini);
1327
1328static int __net_init xt_net_init(struct net *net)
1329{
1330 int i;
1331
1332 for (i = 0; i < NFPROTO_NUMPROTO; i++)
1333 INIT_LIST_HEAD(&net->xt.tables[i]);
1334 return 0;
1335}
1336
1337static struct pernet_operations xt_net_ops = {
1338 .init = xt_net_init,
1339};
1340
1341static int __init xt_init(void)
1342{
1343 unsigned int i;
1344 int rv;
1345
1346 for_each_possible_cpu(i) {
1347 seqcount_init(&per_cpu(xt_recseq, i));
1348 }
1349
1350 xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);
1351 if (!xt)
1352 return -ENOMEM;
1353
1354 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
1355 mutex_init(&xt[i].mutex);
1356#ifdef CONFIG_COMPAT
1357 mutex_init(&xt[i].compat_mutex);
1358 xt[i].compat_tab = NULL;
1359#endif
1360 INIT_LIST_HEAD(&xt[i].target);
1361 INIT_LIST_HEAD(&xt[i].match);
1362 }
1363 rv = register_pernet_subsys(&xt_net_ops);
1364 if (rv < 0)
1365 kfree(xt);
1366 return rv;
1367}
1368
1369static void __exit xt_fini(void)
1370{
1371 unregister_pernet_subsys(&xt_net_ops);
1372 kfree(xt);
1373}
1374
1375module_init(xt_init);
1376module_exit(xt_fini);
1377
Linux kernel - Deliverables
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