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 <linux/user_namespace.h>
30 #include <net/net_namespace.h>
31
32 #include <linux/netfilter/x_tables.h>
33 #include <linux/netfilter_arp.h>
34 #include <linux/netfilter_ipv4/ip_tables.h>
35 #include <linux/netfilter_ipv6/ip6_tables.h>
36 #include <linux/netfilter_arp/arp_tables.h>
37
38 MODULE_LICENSE("GPL");
39 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
40 MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
41
42 #define XT_PCPU_BLOCK_SIZE 4096
43
44 struct compat_delta {
45 unsigned int offset; /* offset in kernel */
46 int delta; /* delta in 32bit user land */
47 };
48
49 struct xt_af {
50 struct mutex mutex;
51 struct list_head match;
52 struct list_head target;
53 #ifdef CONFIG_COMPAT
54 struct mutex compat_mutex;
55 struct compat_delta *compat_tab;
56 unsigned int number; /* number of slots in compat_tab[] */
57 unsigned int cur; /* number of used slots in compat_tab[] */
58 #endif
59 };
60
61 static struct xt_af *xt;
62
63 static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
64 [NFPROTO_UNSPEC] = "x",
65 [NFPROTO_IPV4] = "ip",
66 [NFPROTO_ARP] = "arp",
67 [NFPROTO_BRIDGE] = "eb",
68 [NFPROTO_IPV6] = "ip6",
69 };
70
71 /* Registration hooks for targets. */
xt_register_target(struct xt_target * target)72 int xt_register_target(struct xt_target *target)
73 {
74 u_int8_t af = target->family;
75
76 mutex_lock(&xt[af].mutex);
77 list_add(&target->list, &xt[af].target);
78 mutex_unlock(&xt[af].mutex);
79 return 0;
80 }
81 EXPORT_SYMBOL(xt_register_target);
82
83 void
xt_unregister_target(struct xt_target * target)84 xt_unregister_target(struct xt_target *target)
85 {
86 u_int8_t af = target->family;
87
88 mutex_lock(&xt[af].mutex);
89 list_del(&target->list);
90 mutex_unlock(&xt[af].mutex);
91 }
92 EXPORT_SYMBOL(xt_unregister_target);
93
94 int
xt_register_targets(struct xt_target * target,unsigned int n)95 xt_register_targets(struct xt_target *target, unsigned int n)
96 {
97 unsigned int i;
98 int err = 0;
99
100 for (i = 0; i < n; i++) {
101 err = xt_register_target(&target[i]);
102 if (err)
103 goto err;
104 }
105 return err;
106
107 err:
108 if (i > 0)
109 xt_unregister_targets(target, i);
110 return err;
111 }
112 EXPORT_SYMBOL(xt_register_targets);
113
114 void
xt_unregister_targets(struct xt_target * target,unsigned int n)115 xt_unregister_targets(struct xt_target *target, unsigned int n)
116 {
117 while (n-- > 0)
118 xt_unregister_target(&target[n]);
119 }
120 EXPORT_SYMBOL(xt_unregister_targets);
121
xt_register_match(struct xt_match * match)122 int xt_register_match(struct xt_match *match)
123 {
124 u_int8_t af = match->family;
125
126 mutex_lock(&xt[af].mutex);
127 list_add(&match->list, &xt[af].match);
128 mutex_unlock(&xt[af].mutex);
129 return 0;
130 }
131 EXPORT_SYMBOL(xt_register_match);
132
133 void
xt_unregister_match(struct xt_match * match)134 xt_unregister_match(struct xt_match *match)
135 {
136 u_int8_t af = match->family;
137
138 mutex_lock(&xt[af].mutex);
139 list_del(&match->list);
140 mutex_unlock(&xt[af].mutex);
141 }
142 EXPORT_SYMBOL(xt_unregister_match);
143
144 int
xt_register_matches(struct xt_match * match,unsigned int n)145 xt_register_matches(struct xt_match *match, unsigned int n)
146 {
147 unsigned int i;
148 int err = 0;
149
150 for (i = 0; i < n; i++) {
151 err = xt_register_match(&match[i]);
152 if (err)
153 goto err;
154 }
155 return err;
156
157 err:
158 if (i > 0)
159 xt_unregister_matches(match, i);
160 return err;
161 }
162 EXPORT_SYMBOL(xt_register_matches);
163
164 void
xt_unregister_matches(struct xt_match * match,unsigned int n)165 xt_unregister_matches(struct xt_match *match, unsigned int n)
166 {
167 while (n-- > 0)
168 xt_unregister_match(&match[n]);
169 }
170 EXPORT_SYMBOL(xt_unregister_matches);
171
172
173 /*
174 * These are weird, but module loading must not be done with mutex
175 * held (since they will register), and we have to have a single
176 * function to use.
177 */
178
179 /* Find match, grabs ref. Returns ERR_PTR() on error. */
xt_find_match(u8 af,const char * name,u8 revision)180 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
181 {
182 struct xt_match *m;
183 int err = -ENOENT;
184
185 mutex_lock(&xt[af].mutex);
186 list_for_each_entry(m, &xt[af].match, list) {
187 if (strcmp(m->name, name) == 0) {
188 if (m->revision == revision) {
189 if (try_module_get(m->me)) {
190 mutex_unlock(&xt[af].mutex);
191 return m;
192 }
193 } else
194 err = -EPROTOTYPE; /* Found something. */
195 }
196 }
197 mutex_unlock(&xt[af].mutex);
198
199 if (af != NFPROTO_UNSPEC)
200 /* Try searching again in the family-independent list */
201 return xt_find_match(NFPROTO_UNSPEC, name, revision);
202
203 return ERR_PTR(err);
204 }
205 EXPORT_SYMBOL(xt_find_match);
206
207 struct xt_match *
xt_request_find_match(uint8_t nfproto,const char * name,uint8_t revision)208 xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
209 {
210 struct xt_match *match;
211
212 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
213 return ERR_PTR(-EINVAL);
214
215 match = xt_find_match(nfproto, name, revision);
216 if (IS_ERR(match)) {
217 request_module("%st_%s", xt_prefix[nfproto], name);
218 match = xt_find_match(nfproto, name, revision);
219 }
220
221 return match;
222 }
223 EXPORT_SYMBOL_GPL(xt_request_find_match);
224
225 /* Find target, grabs ref. Returns ERR_PTR() on error. */
xt_find_target(u8 af,const char * name,u8 revision)226 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
227 {
228 struct xt_target *t;
229 int err = -ENOENT;
230
231 mutex_lock(&xt[af].mutex);
232 list_for_each_entry(t, &xt[af].target, list) {
233 if (strcmp(t->name, name) == 0) {
234 if (t->revision == revision) {
235 if (try_module_get(t->me)) {
236 mutex_unlock(&xt[af].mutex);
237 return t;
238 }
239 } else
240 err = -EPROTOTYPE; /* Found something. */
241 }
242 }
243 mutex_unlock(&xt[af].mutex);
244
245 if (af != NFPROTO_UNSPEC)
246 /* Try searching again in the family-independent list */
247 return xt_find_target(NFPROTO_UNSPEC, name, revision);
248
249 return ERR_PTR(err);
250 }
251 EXPORT_SYMBOL(xt_find_target);
252
xt_request_find_target(u8 af,const char * name,u8 revision)253 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
254 {
255 struct xt_target *target;
256
257 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
258 return ERR_PTR(-EINVAL);
259
260 target = xt_find_target(af, name, revision);
261 if (IS_ERR(target)) {
262 request_module("%st_%s", xt_prefix[af], name);
263 target = xt_find_target(af, name, revision);
264 }
265
266 return target;
267 }
268 EXPORT_SYMBOL_GPL(xt_request_find_target);
269
match_revfn(u8 af,const char * name,u8 revision,int * bestp)270 static int match_revfn(u8 af, const char *name, u8 revision, int *bestp)
271 {
272 const struct xt_match *m;
273 int have_rev = 0;
274
275 list_for_each_entry(m, &xt[af].match, list) {
276 if (strcmp(m->name, name) == 0) {
277 if (m->revision > *bestp)
278 *bestp = m->revision;
279 if (m->revision == revision)
280 have_rev = 1;
281 }
282 }
283
284 if (af != NFPROTO_UNSPEC && !have_rev)
285 return match_revfn(NFPROTO_UNSPEC, name, revision, bestp);
286
287 return have_rev;
288 }
289
target_revfn(u8 af,const char * name,u8 revision,int * bestp)290 static int target_revfn(u8 af, const char *name, u8 revision, int *bestp)
291 {
292 const struct xt_target *t;
293 int have_rev = 0;
294
295 list_for_each_entry(t, &xt[af].target, list) {
296 if (strcmp(t->name, name) == 0) {
297 if (t->revision > *bestp)
298 *bestp = t->revision;
299 if (t->revision == revision)
300 have_rev = 1;
301 }
302 }
303
304 if (af != NFPROTO_UNSPEC && !have_rev)
305 return target_revfn(NFPROTO_UNSPEC, name, revision, bestp);
306
307 return have_rev;
308 }
309
310 /* Returns true or false (if no such extension at all) */
xt_find_revision(u8 af,const char * name,u8 revision,int target,int * err)311 int xt_find_revision(u8 af, const char *name, u8 revision, int target,
312 int *err)
313 {
314 int have_rev, best = -1;
315
316 mutex_lock(&xt[af].mutex);
317 if (target == 1)
318 have_rev = target_revfn(af, name, revision, &best);
319 else
320 have_rev = match_revfn(af, name, revision, &best);
321 mutex_unlock(&xt[af].mutex);
322
323 /* Nothing at all? Return 0 to try loading module. */
324 if (best == -1) {
325 *err = -ENOENT;
326 return 0;
327 }
328
329 *err = best;
330 if (!have_rev)
331 *err = -EPROTONOSUPPORT;
332 return 1;
333 }
334 EXPORT_SYMBOL_GPL(xt_find_revision);
335
336 static char *
textify_hooks(char * buf,size_t size,unsigned int mask,uint8_t nfproto)337 textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto)
338 {
339 static const char *const inetbr_names[] = {
340 "PREROUTING", "INPUT", "FORWARD",
341 "OUTPUT", "POSTROUTING", "BROUTING",
342 };
343 static const char *const arp_names[] = {
344 "INPUT", "FORWARD", "OUTPUT",
345 };
346 const char *const *names;
347 unsigned int i, max;
348 char *p = buf;
349 bool np = false;
350 int res;
351
352 names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names;
353 max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) :
354 ARRAY_SIZE(inetbr_names);
355 *p = '\0';
356 for (i = 0; i < max; ++i) {
357 if (!(mask & (1 << i)))
358 continue;
359 res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]);
360 if (res > 0) {
361 size -= res;
362 p += res;
363 }
364 np = true;
365 }
366
367 return buf;
368 }
369
370 /**
371 * xt_check_proc_name - check that name is suitable for /proc file creation
372 *
373 * @name: file name candidate
374 * @size: length of buffer
375 *
376 * some x_tables modules wish to create a file in /proc.
377 * This function makes sure that the name is suitable for this
378 * purpose, it checks that name is NUL terminated and isn't a 'special'
379 * name, like "..".
380 *
381 * returns negative number on error or 0 if name is useable.
382 */
xt_check_proc_name(const char * name,unsigned int size)383 int xt_check_proc_name(const char *name, unsigned int size)
384 {
385 if (name[0] == '\0')
386 return -EINVAL;
387
388 if (strnlen(name, size) == size)
389 return -ENAMETOOLONG;
390
391 if (strcmp(name, ".") == 0 ||
392 strcmp(name, "..") == 0 ||
393 strchr(name, '/'))
394 return -EINVAL;
395
396 return 0;
397 }
398 EXPORT_SYMBOL(xt_check_proc_name);
399
xt_check_match(struct xt_mtchk_param * par,unsigned int size,u_int8_t proto,bool inv_proto)400 int xt_check_match(struct xt_mtchk_param *par,
401 unsigned int size, u_int8_t proto, bool inv_proto)
402 {
403 int ret;
404
405 if (XT_ALIGN(par->match->matchsize) != size &&
406 par->match->matchsize != -1) {
407 /*
408 * ebt_among is exempt from centralized matchsize checking
409 * because it uses a dynamic-size data set.
410 */
411 pr_err("%s_tables: %s.%u match: invalid size "
412 "%u (kernel) != (user) %u\n",
413 xt_prefix[par->family], par->match->name,
414 par->match->revision,
415 XT_ALIGN(par->match->matchsize), size);
416 return -EINVAL;
417 }
418 if (par->match->table != NULL &&
419 strcmp(par->match->table, par->table) != 0) {
420 pr_err("%s_tables: %s match: only valid in %s table, not %s\n",
421 xt_prefix[par->family], par->match->name,
422 par->match->table, par->table);
423 return -EINVAL;
424 }
425 if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
426 char used[64], allow[64];
427
428 pr_err("%s_tables: %s match: used from hooks %s, but only "
429 "valid from %s\n",
430 xt_prefix[par->family], par->match->name,
431 textify_hooks(used, sizeof(used), par->hook_mask,
432 par->family),
433 textify_hooks(allow, sizeof(allow), par->match->hooks,
434 par->family));
435 return -EINVAL;
436 }
437 if (par->match->proto && (par->match->proto != proto || inv_proto)) {
438 pr_err("%s_tables: %s match: only valid for protocol %u\n",
439 xt_prefix[par->family], par->match->name,
440 par->match->proto);
441 return -EINVAL;
442 }
443 if (par->match->checkentry != NULL) {
444 ret = par->match->checkentry(par);
445 if (ret < 0)
446 return ret;
447 else if (ret > 0)
448 /* Flag up potential errors. */
449 return -EIO;
450 }
451 return 0;
452 }
453 EXPORT_SYMBOL_GPL(xt_check_match);
454
455 /** xt_check_entry_match - check that matches end before start of target
456 *
457 * @match: beginning of xt_entry_match
458 * @target: beginning of this rules target (alleged end of matches)
459 * @alignment: alignment requirement of match structures
460 *
461 * Validates that all matches add up to the beginning of the target,
462 * and that each match covers at least the base structure size.
463 *
464 * Return: 0 on success, negative errno on failure.
465 */
xt_check_entry_match(const char * match,const char * target,const size_t alignment)466 static int xt_check_entry_match(const char *match, const char *target,
467 const size_t alignment)
468 {
469 const struct xt_entry_match *pos;
470 int length = target - match;
471
472 if (length == 0) /* no matches */
473 return 0;
474
475 pos = (struct xt_entry_match *)match;
476 do {
477 if ((unsigned long)pos % alignment)
478 return -EINVAL;
479
480 if (length < (int)sizeof(struct xt_entry_match))
481 return -EINVAL;
482
483 if (pos->u.match_size < sizeof(struct xt_entry_match))
484 return -EINVAL;
485
486 if (pos->u.match_size > length)
487 return -EINVAL;
488
489 length -= pos->u.match_size;
490 pos = ((void *)((char *)(pos) + (pos)->u.match_size));
491 } while (length > 0);
492
493 return 0;
494 }
495
496 #ifdef CONFIG_COMPAT
xt_compat_add_offset(u_int8_t af,unsigned int offset,int delta)497 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
498 {
499 struct xt_af *xp = &xt[af];
500
501 if (!xp->compat_tab) {
502 if (!xp->number)
503 return -EINVAL;
504 xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
505 if (!xp->compat_tab)
506 return -ENOMEM;
507 xp->cur = 0;
508 }
509
510 if (xp->cur >= xp->number)
511 return -EINVAL;
512
513 if (xp->cur)
514 delta += xp->compat_tab[xp->cur - 1].delta;
515 xp->compat_tab[xp->cur].offset = offset;
516 xp->compat_tab[xp->cur].delta = delta;
517 xp->cur++;
518 return 0;
519 }
520 EXPORT_SYMBOL_GPL(xt_compat_add_offset);
521
xt_compat_flush_offsets(u_int8_t af)522 void xt_compat_flush_offsets(u_int8_t af)
523 {
524 if (xt[af].compat_tab) {
525 vfree(xt[af].compat_tab);
526 xt[af].compat_tab = NULL;
527 xt[af].number = 0;
528 xt[af].cur = 0;
529 }
530 }
531 EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
532
xt_compat_calc_jump(u_int8_t af,unsigned int offset)533 int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
534 {
535 struct compat_delta *tmp = xt[af].compat_tab;
536 int mid, left = 0, right = xt[af].cur - 1;
537
538 while (left <= right) {
539 mid = (left + right) >> 1;
540 if (offset > tmp[mid].offset)
541 left = mid + 1;
542 else if (offset < tmp[mid].offset)
543 right = mid - 1;
544 else
545 return mid ? tmp[mid - 1].delta : 0;
546 }
547 return left ? tmp[left - 1].delta : 0;
548 }
549 EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
550
xt_compat_init_offsets(u_int8_t af,unsigned int number)551 void xt_compat_init_offsets(u_int8_t af, unsigned int number)
552 {
553 xt[af].number = number;
554 xt[af].cur = 0;
555 }
556 EXPORT_SYMBOL(xt_compat_init_offsets);
557
xt_compat_match_offset(const struct xt_match * match)558 int xt_compat_match_offset(const struct xt_match *match)
559 {
560 u_int16_t csize = match->compatsize ? : match->matchsize;
561 return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
562 }
563 EXPORT_SYMBOL_GPL(xt_compat_match_offset);
564
xt_compat_match_from_user(struct xt_entry_match * m,void ** dstptr,unsigned int * size)565 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
566 unsigned int *size)
567 {
568 const struct xt_match *match = m->u.kernel.match;
569 struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
570 int pad, off = xt_compat_match_offset(match);
571 u_int16_t msize = cm->u.user.match_size;
572 char name[sizeof(m->u.user.name)];
573
574 m = *dstptr;
575 memcpy(m, cm, sizeof(*cm));
576 if (match->compat_from_user)
577 match->compat_from_user(m->data, cm->data);
578 else
579 memcpy(m->data, cm->data, msize - sizeof(*cm));
580 pad = XT_ALIGN(match->matchsize) - match->matchsize;
581 if (pad > 0)
582 memset(m->data + match->matchsize, 0, pad);
583
584 msize += off;
585 m->u.user.match_size = msize;
586 strlcpy(name, match->name, sizeof(name));
587 module_put(match->me);
588 strncpy(m->u.user.name, name, sizeof(m->u.user.name));
589
590 *size += off;
591 *dstptr += msize;
592 }
593 EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
594
xt_compat_match_to_user(const struct xt_entry_match * m,void __user ** dstptr,unsigned int * size)595 int xt_compat_match_to_user(const struct xt_entry_match *m,
596 void __user **dstptr, unsigned int *size)
597 {
598 const struct xt_match *match = m->u.kernel.match;
599 struct compat_xt_entry_match __user *cm = *dstptr;
600 int off = xt_compat_match_offset(match);
601 u_int16_t msize = m->u.user.match_size - off;
602
603 if (copy_to_user(cm, m, sizeof(*cm)) ||
604 put_user(msize, &cm->u.user.match_size) ||
605 copy_to_user(cm->u.user.name, m->u.kernel.match->name,
606 strlen(m->u.kernel.match->name) + 1))
607 return -EFAULT;
608
609 if (match->compat_to_user) {
610 if (match->compat_to_user((void __user *)cm->data, m->data))
611 return -EFAULT;
612 } else {
613 if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
614 return -EFAULT;
615 }
616
617 *size -= off;
618 *dstptr += msize;
619 return 0;
620 }
621 EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
622
623 /* non-compat version may have padding after verdict */
624 struct compat_xt_standard_target {
625 struct compat_xt_entry_target t;
626 compat_uint_t verdict;
627 };
628
xt_compat_check_entry_offsets(const void * base,const char * elems,unsigned int target_offset,unsigned int next_offset)629 int xt_compat_check_entry_offsets(const void *base, const char *elems,
630 unsigned int target_offset,
631 unsigned int next_offset)
632 {
633 long size_of_base_struct = elems - (const char *)base;
634 const struct compat_xt_entry_target *t;
635 const char *e = base;
636
637 if (target_offset < size_of_base_struct)
638 return -EINVAL;
639
640 if (target_offset + sizeof(*t) > next_offset)
641 return -EINVAL;
642
643 t = (void *)(e + target_offset);
644 if (t->u.target_size < sizeof(*t))
645 return -EINVAL;
646
647 if (target_offset + t->u.target_size > next_offset)
648 return -EINVAL;
649
650 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
651 COMPAT_XT_ALIGN(target_offset + sizeof(struct compat_xt_standard_target)) != next_offset)
652 return -EINVAL;
653
654 /* compat_xt_entry match has less strict aligment requirements,
655 * otherwise they are identical. In case of padding differences
656 * we need to add compat version of xt_check_entry_match.
657 */
658 BUILD_BUG_ON(sizeof(struct compat_xt_entry_match) != sizeof(struct xt_entry_match));
659
660 return xt_check_entry_match(elems, base + target_offset,
661 __alignof__(struct compat_xt_entry_match));
662 }
663 EXPORT_SYMBOL(xt_compat_check_entry_offsets);
664 #endif /* CONFIG_COMPAT */
665
666 /**
667 * xt_check_entry_offsets - validate arp/ip/ip6t_entry
668 *
669 * @base: pointer to arp/ip/ip6t_entry
670 * @elems: pointer to first xt_entry_match, i.e. ip(6)t_entry->elems
671 * @target_offset: the arp/ip/ip6_t->target_offset
672 * @next_offset: the arp/ip/ip6_t->next_offset
673 *
674 * validates that target_offset and next_offset are sane and that all
675 * match sizes (if any) align with the target offset.
676 *
677 * This function does not validate the targets or matches themselves, it
678 * only tests that all the offsets and sizes are correct, that all
679 * match structures are aligned, and that the last structure ends where
680 * the target structure begins.
681 *
682 * Also see xt_compat_check_entry_offsets for CONFIG_COMPAT version.
683 *
684 * The arp/ip/ip6t_entry structure @base must have passed following tests:
685 * - it must point to a valid memory location
686 * - base to base + next_offset must be accessible, i.e. not exceed allocated
687 * length.
688 *
689 * A well-formed entry looks like this:
690 *
691 * ip(6)t_entry match [mtdata] match [mtdata] target [tgdata] ip(6)t_entry
692 * e->elems[]-----' | |
693 * matchsize | |
694 * matchsize | |
695 * | |
696 * target_offset---------------------------------' |
697 * next_offset---------------------------------------------------'
698 *
699 * elems[]: flexible array member at end of ip(6)/arpt_entry struct.
700 * This is where matches (if any) and the target reside.
701 * target_offset: beginning of target.
702 * next_offset: start of the next rule; also: size of this rule.
703 * Since targets have a minimum size, target_offset + minlen <= next_offset.
704 *
705 * Every match stores its size, sum of sizes must not exceed target_offset.
706 *
707 * Return: 0 on success, negative errno on failure.
708 */
xt_check_entry_offsets(const void * base,const char * elems,unsigned int target_offset,unsigned int next_offset)709 int xt_check_entry_offsets(const void *base,
710 const char *elems,
711 unsigned int target_offset,
712 unsigned int next_offset)
713 {
714 long size_of_base_struct = elems - (const char *)base;
715 const struct xt_entry_target *t;
716 const char *e = base;
717
718 /* target start is within the ip/ip6/arpt_entry struct */
719 if (target_offset < size_of_base_struct)
720 return -EINVAL;
721
722 if (target_offset + sizeof(*t) > next_offset)
723 return -EINVAL;
724
725 t = (void *)(e + target_offset);
726 if (t->u.target_size < sizeof(*t))
727 return -EINVAL;
728
729 if (target_offset + t->u.target_size > next_offset)
730 return -EINVAL;
731
732 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
733 XT_ALIGN(target_offset + sizeof(struct xt_standard_target)) != next_offset)
734 return -EINVAL;
735
736 return xt_check_entry_match(elems, base + target_offset,
737 __alignof__(struct xt_entry_match));
738 }
739 EXPORT_SYMBOL(xt_check_entry_offsets);
740
741 /**
742 * xt_alloc_entry_offsets - allocate array to store rule head offsets
743 *
744 * @size: number of entries
745 *
746 * Return: NULL or kmalloc'd or vmalloc'd array
747 */
xt_alloc_entry_offsets(unsigned int size)748 unsigned int *xt_alloc_entry_offsets(unsigned int size)
749 {
750 unsigned int *off;
751
752 off = kcalloc(size, sizeof(unsigned int), GFP_KERNEL | __GFP_NOWARN);
753
754 if (off)
755 return off;
756
757 if (size < (SIZE_MAX / sizeof(unsigned int)))
758 off = vmalloc(size * sizeof(unsigned int));
759
760 return off;
761 }
762 EXPORT_SYMBOL(xt_alloc_entry_offsets);
763
764 /**
765 * xt_find_jump_offset - check if target is a valid jump offset
766 *
767 * @offsets: array containing all valid rule start offsets of a rule blob
768 * @target: the jump target to search for
769 * @size: entries in @offset
770 */
xt_find_jump_offset(const unsigned int * offsets,unsigned int target,unsigned int size)771 bool xt_find_jump_offset(const unsigned int *offsets,
772 unsigned int target, unsigned int size)
773 {
774 int m, low = 0, hi = size;
775
776 while (hi > low) {
777 m = (low + hi) / 2u;
778
779 if (offsets[m] > target)
780 hi = m;
781 else if (offsets[m] < target)
782 low = m + 1;
783 else
784 return true;
785 }
786
787 return false;
788 }
789 EXPORT_SYMBOL(xt_find_jump_offset);
790
xt_check_target(struct xt_tgchk_param * par,unsigned int size,u_int8_t proto,bool inv_proto)791 int xt_check_target(struct xt_tgchk_param *par,
792 unsigned int size, u_int8_t proto, bool inv_proto)
793 {
794 int ret;
795
796 if (XT_ALIGN(par->target->targetsize) != size) {
797 pr_err("%s_tables: %s.%u target: invalid size "
798 "%u (kernel) != (user) %u\n",
799 xt_prefix[par->family], par->target->name,
800 par->target->revision,
801 XT_ALIGN(par->target->targetsize), size);
802 return -EINVAL;
803 }
804 if (par->target->table != NULL &&
805 strcmp(par->target->table, par->table) != 0) {
806 pr_err("%s_tables: %s target: only valid in %s table, not %s\n",
807 xt_prefix[par->family], par->target->name,
808 par->target->table, par->table);
809 return -EINVAL;
810 }
811 if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
812 char used[64], allow[64];
813
814 pr_err("%s_tables: %s target: used from hooks %s, but only "
815 "usable from %s\n",
816 xt_prefix[par->family], par->target->name,
817 textify_hooks(used, sizeof(used), par->hook_mask,
818 par->family),
819 textify_hooks(allow, sizeof(allow), par->target->hooks,
820 par->family));
821 return -EINVAL;
822 }
823 if (par->target->proto && (par->target->proto != proto || inv_proto)) {
824 pr_err("%s_tables: %s target: only valid for protocol %u\n",
825 xt_prefix[par->family], par->target->name,
826 par->target->proto);
827 return -EINVAL;
828 }
829 if (par->target->checkentry != NULL) {
830 ret = par->target->checkentry(par);
831 if (ret < 0)
832 return ret;
833 else if (ret > 0)
834 /* Flag up potential errors. */
835 return -EIO;
836 }
837 return 0;
838 }
839 EXPORT_SYMBOL_GPL(xt_check_target);
840
841 /**
842 * xt_copy_counters_from_user - copy counters and metadata from userspace
843 *
844 * @user: src pointer to userspace memory
845 * @len: alleged size of userspace memory
846 * @info: where to store the xt_counters_info metadata
847 * @compat: true if we setsockopt call is done by 32bit task on 64bit kernel
848 *
849 * Copies counter meta data from @user and stores it in @info.
850 *
851 * vmallocs memory to hold the counters, then copies the counter data
852 * from @user to the new memory and returns a pointer to it.
853 *
854 * If @compat is true, @info gets converted automatically to the 64bit
855 * representation.
856 *
857 * The metadata associated with the counters is stored in @info.
858 *
859 * Return: returns pointer that caller has to test via IS_ERR().
860 * If IS_ERR is false, caller has to vfree the pointer.
861 */
xt_copy_counters_from_user(const void __user * user,unsigned int len,struct xt_counters_info * info,bool compat)862 void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
863 struct xt_counters_info *info, bool compat)
864 {
865 void *mem;
866 u64 size;
867
868 #ifdef CONFIG_COMPAT
869 if (compat) {
870 /* structures only differ in size due to alignment */
871 struct compat_xt_counters_info compat_tmp;
872
873 if (len <= sizeof(compat_tmp))
874 return ERR_PTR(-EINVAL);
875
876 len -= sizeof(compat_tmp);
877 if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0)
878 return ERR_PTR(-EFAULT);
879
880 strlcpy(info->name, compat_tmp.name, sizeof(info->name));
881 info->num_counters = compat_tmp.num_counters;
882 user += sizeof(compat_tmp);
883 } else
884 #endif
885 {
886 if (len <= sizeof(*info))
887 return ERR_PTR(-EINVAL);
888
889 len -= sizeof(*info);
890 if (copy_from_user(info, user, sizeof(*info)) != 0)
891 return ERR_PTR(-EFAULT);
892
893 info->name[sizeof(info->name) - 1] = '\0';
894 user += sizeof(*info);
895 }
896
897 size = sizeof(struct xt_counters);
898 size *= info->num_counters;
899
900 if (size != (u64)len)
901 return ERR_PTR(-EINVAL);
902
903 mem = vmalloc(len);
904 if (!mem)
905 return ERR_PTR(-ENOMEM);
906
907 if (copy_from_user(mem, user, len) == 0)
908 return mem;
909
910 vfree(mem);
911 return ERR_PTR(-EFAULT);
912 }
913 EXPORT_SYMBOL_GPL(xt_copy_counters_from_user);
914
915 #ifdef CONFIG_COMPAT
xt_compat_target_offset(const struct xt_target * target)916 int xt_compat_target_offset(const struct xt_target *target)
917 {
918 u_int16_t csize = target->compatsize ? : target->targetsize;
919 return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
920 }
921 EXPORT_SYMBOL_GPL(xt_compat_target_offset);
922
xt_compat_target_from_user(struct xt_entry_target * t,void ** dstptr,unsigned int * size)923 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
924 unsigned int *size)
925 {
926 const struct xt_target *target = t->u.kernel.target;
927 struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
928 int pad, off = xt_compat_target_offset(target);
929 u_int16_t tsize = ct->u.user.target_size;
930 char name[sizeof(t->u.user.name)];
931
932 t = *dstptr;
933 memcpy(t, ct, sizeof(*ct));
934 if (target->compat_from_user)
935 target->compat_from_user(t->data, ct->data);
936 else
937 memcpy(t->data, ct->data, tsize - sizeof(*ct));
938 pad = XT_ALIGN(target->targetsize) - target->targetsize;
939 if (pad > 0)
940 memset(t->data + target->targetsize, 0, pad);
941
942 tsize += off;
943 t->u.user.target_size = tsize;
944 strlcpy(name, target->name, sizeof(name));
945 module_put(target->me);
946 strncpy(t->u.user.name, name, sizeof(t->u.user.name));
947
948 *size += off;
949 *dstptr += tsize;
950 }
951 EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
952
xt_compat_target_to_user(const struct xt_entry_target * t,void __user ** dstptr,unsigned int * size)953 int xt_compat_target_to_user(const struct xt_entry_target *t,
954 void __user **dstptr, unsigned int *size)
955 {
956 const struct xt_target *target = t->u.kernel.target;
957 struct compat_xt_entry_target __user *ct = *dstptr;
958 int off = xt_compat_target_offset(target);
959 u_int16_t tsize = t->u.user.target_size - off;
960
961 if (copy_to_user(ct, t, sizeof(*ct)) ||
962 put_user(tsize, &ct->u.user.target_size) ||
963 copy_to_user(ct->u.user.name, t->u.kernel.target->name,
964 strlen(t->u.kernel.target->name) + 1))
965 return -EFAULT;
966
967 if (target->compat_to_user) {
968 if (target->compat_to_user((void __user *)ct->data, t->data))
969 return -EFAULT;
970 } else {
971 if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
972 return -EFAULT;
973 }
974
975 *size -= off;
976 *dstptr += tsize;
977 return 0;
978 }
979 EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
980 #endif
981
xt_alloc_table_info(unsigned int size)982 struct xt_table_info *xt_alloc_table_info(unsigned int size)
983 {
984 struct xt_table_info *info = NULL;
985 size_t sz = sizeof(*info) + size;
986
987 if (sz < sizeof(*info))
988 return NULL;
989
990 /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
991 if ((size >> PAGE_SHIFT) + 2 > totalram_pages)
992 return NULL;
993
994 if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
995 info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
996 if (!info) {
997 info = vmalloc(sz);
998 if (!info)
999 return NULL;
1000 }
1001 memset(info, 0, sizeof(*info));
1002 info->size = size;
1003 return info;
1004 }
1005 EXPORT_SYMBOL(xt_alloc_table_info);
1006
xt_free_table_info(struct xt_table_info * info)1007 void xt_free_table_info(struct xt_table_info *info)
1008 {
1009 int cpu;
1010
1011 if (info->jumpstack != NULL) {
1012 for_each_possible_cpu(cpu)
1013 kvfree(info->jumpstack[cpu]);
1014 kvfree(info->jumpstack);
1015 }
1016
1017 kvfree(info);
1018 }
1019 EXPORT_SYMBOL(xt_free_table_info);
1020
1021 /* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */
xt_find_table_lock(struct net * net,u_int8_t af,const char * name)1022 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
1023 const char *name)
1024 {
1025 struct xt_table *t, *found = NULL;
1026
1027 mutex_lock(&xt[af].mutex);
1028 list_for_each_entry(t, &net->xt.tables[af], list)
1029 if (strcmp(t->name, name) == 0 && try_module_get(t->me))
1030 return t;
1031
1032 if (net == &init_net)
1033 goto out;
1034
1035 /* Table doesn't exist in this netns, re-try init */
1036 list_for_each_entry(t, &init_net.xt.tables[af], list) {
1037 if (strcmp(t->name, name))
1038 continue;
1039 if (!try_module_get(t->me)) {
1040 mutex_unlock(&xt[af].mutex);
1041 return NULL;
1042 }
1043
1044 mutex_unlock(&xt[af].mutex);
1045 if (t->table_init(net) != 0) {
1046 module_put(t->me);
1047 return NULL;
1048 }
1049
1050 found = t;
1051
1052 mutex_lock(&xt[af].mutex);
1053 break;
1054 }
1055
1056 if (!found)
1057 goto out;
1058
1059 /* and once again: */
1060 list_for_each_entry(t, &net->xt.tables[af], list)
1061 if (strcmp(t->name, name) == 0)
1062 return t;
1063
1064 module_put(found->me);
1065 out:
1066 mutex_unlock(&xt[af].mutex);
1067 return NULL;
1068 }
1069 EXPORT_SYMBOL_GPL(xt_find_table_lock);
1070
xt_table_unlock(struct xt_table * table)1071 void xt_table_unlock(struct xt_table *table)
1072 {
1073 mutex_unlock(&xt[table->af].mutex);
1074 }
1075 EXPORT_SYMBOL_GPL(xt_table_unlock);
1076
1077 #ifdef CONFIG_COMPAT
xt_compat_lock(u_int8_t af)1078 void xt_compat_lock(u_int8_t af)
1079 {
1080 mutex_lock(&xt[af].compat_mutex);
1081 }
1082 EXPORT_SYMBOL_GPL(xt_compat_lock);
1083
xt_compat_unlock(u_int8_t af)1084 void xt_compat_unlock(u_int8_t af)
1085 {
1086 mutex_unlock(&xt[af].compat_mutex);
1087 }
1088 EXPORT_SYMBOL_GPL(xt_compat_unlock);
1089 #endif
1090
1091 DEFINE_PER_CPU(seqcount_t, xt_recseq);
1092 EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
1093
1094 struct static_key xt_tee_enabled __read_mostly;
1095 EXPORT_SYMBOL_GPL(xt_tee_enabled);
1096
xt_jumpstack_alloc(struct xt_table_info * i)1097 static int xt_jumpstack_alloc(struct xt_table_info *i)
1098 {
1099 unsigned int size;
1100 int cpu;
1101
1102 size = sizeof(void **) * nr_cpu_ids;
1103 if (size > PAGE_SIZE)
1104 i->jumpstack = vzalloc(size);
1105 else
1106 i->jumpstack = kzalloc(size, GFP_KERNEL);
1107 if (i->jumpstack == NULL)
1108 return -ENOMEM;
1109
1110 /* ruleset without jumps -- no stack needed */
1111 if (i->stacksize == 0)
1112 return 0;
1113
1114 /* Jumpstack needs to be able to record two full callchains, one
1115 * from the first rule set traversal, plus one table reentrancy
1116 * via -j TEE without clobbering the callchain that brought us to
1117 * TEE target.
1118 *
1119 * This is done by allocating two jumpstacks per cpu, on reentry
1120 * the upper half of the stack is used.
1121 *
1122 * see the jumpstack setup in ipt_do_table() for more details.
1123 */
1124 size = sizeof(void *) * i->stacksize * 2u;
1125 for_each_possible_cpu(cpu) {
1126 if (size > PAGE_SIZE)
1127 i->jumpstack[cpu] = vmalloc_node(size,
1128 cpu_to_node(cpu));
1129 else
1130 i->jumpstack[cpu] = kmalloc_node(size,
1131 GFP_KERNEL, cpu_to_node(cpu));
1132 if (i->jumpstack[cpu] == NULL)
1133 /*
1134 * Freeing will be done later on by the callers. The
1135 * chain is: xt_replace_table -> __do_replace ->
1136 * do_replace -> xt_free_table_info.
1137 */
1138 return -ENOMEM;
1139 }
1140
1141 return 0;
1142 }
1143
1144 struct xt_table_info *
xt_replace_table(struct xt_table * table,unsigned int num_counters,struct xt_table_info * newinfo,int * error)1145 xt_replace_table(struct xt_table *table,
1146 unsigned int num_counters,
1147 struct xt_table_info *newinfo,
1148 int *error)
1149 {
1150 struct xt_table_info *private;
1151 int ret;
1152
1153 ret = xt_jumpstack_alloc(newinfo);
1154 if (ret < 0) {
1155 *error = ret;
1156 return NULL;
1157 }
1158
1159 /* Do the substitution. */
1160 local_bh_disable();
1161 private = table->private;
1162
1163 /* Check inside lock: is the old number correct? */
1164 if (num_counters != private->number) {
1165 pr_debug("num_counters != table->private->number (%u/%u)\n",
1166 num_counters, private->number);
1167 local_bh_enable();
1168 *error = -EAGAIN;
1169 return NULL;
1170 }
1171
1172 newinfo->initial_entries = private->initial_entries;
1173 /*
1174 * Ensure contents of newinfo are visible before assigning to
1175 * private.
1176 */
1177 smp_wmb();
1178 table->private = newinfo;
1179
1180 /*
1181 * Even though table entries have now been swapped, other CPU's
1182 * may still be using the old entries. This is okay, because
1183 * resynchronization happens because of the locking done
1184 * during the get_counters() routine.
1185 */
1186 local_bh_enable();
1187
1188 #ifdef CONFIG_AUDIT
1189 if (audit_enabled) {
1190 struct audit_buffer *ab;
1191
1192 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1193 AUDIT_NETFILTER_CFG);
1194 if (ab) {
1195 audit_log_format(ab, "table=%s family=%u entries=%u",
1196 table->name, table->af,
1197 private->number);
1198 audit_log_end(ab);
1199 }
1200 }
1201 #endif
1202
1203 return private;
1204 }
1205 EXPORT_SYMBOL_GPL(xt_replace_table);
1206
xt_register_table(struct net * net,const struct xt_table * input_table,struct xt_table_info * bootstrap,struct xt_table_info * newinfo)1207 struct xt_table *xt_register_table(struct net *net,
1208 const struct xt_table *input_table,
1209 struct xt_table_info *bootstrap,
1210 struct xt_table_info *newinfo)
1211 {
1212 int ret;
1213 struct xt_table_info *private;
1214 struct xt_table *t, *table;
1215
1216 /* Don't add one object to multiple lists. */
1217 table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL);
1218 if (!table) {
1219 ret = -ENOMEM;
1220 goto out;
1221 }
1222
1223 mutex_lock(&xt[table->af].mutex);
1224 /* Don't autoload: we'd eat our tail... */
1225 list_for_each_entry(t, &net->xt.tables[table->af], list) {
1226 if (strcmp(t->name, table->name) == 0) {
1227 ret = -EEXIST;
1228 goto unlock;
1229 }
1230 }
1231
1232 /* Simplifies replace_table code. */
1233 table->private = bootstrap;
1234
1235 if (!xt_replace_table(table, 0, newinfo, &ret))
1236 goto unlock;
1237
1238 private = table->private;
1239 pr_debug("table->private->number = %u\n", private->number);
1240
1241 /* save number of initial entries */
1242 private->initial_entries = private->number;
1243
1244 list_add(&table->list, &net->xt.tables[table->af]);
1245 mutex_unlock(&xt[table->af].mutex);
1246 return table;
1247
1248 unlock:
1249 mutex_unlock(&xt[table->af].mutex);
1250 kfree(table);
1251 out:
1252 return ERR_PTR(ret);
1253 }
1254 EXPORT_SYMBOL_GPL(xt_register_table);
1255
xt_unregister_table(struct xt_table * table)1256 void *xt_unregister_table(struct xt_table *table)
1257 {
1258 struct xt_table_info *private;
1259
1260 mutex_lock(&xt[table->af].mutex);
1261 private = table->private;
1262 list_del(&table->list);
1263 mutex_unlock(&xt[table->af].mutex);
1264 kfree(table);
1265
1266 return private;
1267 }
1268 EXPORT_SYMBOL_GPL(xt_unregister_table);
1269
1270 #ifdef CONFIG_PROC_FS
1271 struct xt_names_priv {
1272 struct seq_net_private p;
1273 u_int8_t af;
1274 };
xt_table_seq_start(struct seq_file * seq,loff_t * pos)1275 static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
1276 {
1277 struct xt_names_priv *priv = seq->private;
1278 struct net *net = seq_file_net(seq);
1279 u_int8_t af = priv->af;
1280
1281 mutex_lock(&xt[af].mutex);
1282 return seq_list_start(&net->xt.tables[af], *pos);
1283 }
1284
xt_table_seq_next(struct seq_file * seq,void * v,loff_t * pos)1285 static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1286 {
1287 struct xt_names_priv *priv = seq->private;
1288 struct net *net = seq_file_net(seq);
1289 u_int8_t af = priv->af;
1290
1291 return seq_list_next(v, &net->xt.tables[af], pos);
1292 }
1293
xt_table_seq_stop(struct seq_file * seq,void * v)1294 static void xt_table_seq_stop(struct seq_file *seq, void *v)
1295 {
1296 struct xt_names_priv *priv = seq->private;
1297 u_int8_t af = priv->af;
1298
1299 mutex_unlock(&xt[af].mutex);
1300 }
1301
xt_table_seq_show(struct seq_file * seq,void * v)1302 static int xt_table_seq_show(struct seq_file *seq, void *v)
1303 {
1304 struct xt_table *table = list_entry(v, struct xt_table, list);
1305
1306 if (*table->name)
1307 seq_printf(seq, "%s\n", table->name);
1308 return 0;
1309 }
1310
1311 static const struct seq_operations xt_table_seq_ops = {
1312 .start = xt_table_seq_start,
1313 .next = xt_table_seq_next,
1314 .stop = xt_table_seq_stop,
1315 .show = xt_table_seq_show,
1316 };
1317
xt_table_open(struct inode * inode,struct file * file)1318 static int xt_table_open(struct inode *inode, struct file *file)
1319 {
1320 int ret;
1321 struct xt_names_priv *priv;
1322
1323 ret = seq_open_net(inode, file, &xt_table_seq_ops,
1324 sizeof(struct xt_names_priv));
1325 if (!ret) {
1326 priv = ((struct seq_file *)file->private_data)->private;
1327 priv->af = (unsigned long)PDE_DATA(inode);
1328 }
1329 return ret;
1330 }
1331
1332 static const struct file_operations xt_table_ops = {
1333 .owner = THIS_MODULE,
1334 .open = xt_table_open,
1335 .read = seq_read,
1336 .llseek = seq_lseek,
1337 .release = seq_release_net,
1338 };
1339
1340 /*
1341 * Traverse state for ip{,6}_{tables,matches} for helping crossing
1342 * the multi-AF mutexes.
1343 */
1344 struct nf_mttg_trav {
1345 struct list_head *head, *curr;
1346 uint8_t class, nfproto;
1347 };
1348
1349 enum {
1350 MTTG_TRAV_INIT,
1351 MTTG_TRAV_NFP_UNSPEC,
1352 MTTG_TRAV_NFP_SPEC,
1353 MTTG_TRAV_DONE,
1354 };
1355
xt_mttg_seq_next(struct seq_file * seq,void * v,loff_t * ppos,bool is_target)1356 static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
1357 bool is_target)
1358 {
1359 static const uint8_t next_class[] = {
1360 [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
1361 [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE,
1362 };
1363 struct nf_mttg_trav *trav = seq->private;
1364
1365 switch (trav->class) {
1366 case MTTG_TRAV_INIT:
1367 trav->class = MTTG_TRAV_NFP_UNSPEC;
1368 mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
1369 trav->head = trav->curr = is_target ?
1370 &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
1371 break;
1372 case MTTG_TRAV_NFP_UNSPEC:
1373 trav->curr = trav->curr->next;
1374 if (trav->curr != trav->head)
1375 break;
1376 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1377 mutex_lock(&xt[trav->nfproto].mutex);
1378 trav->head = trav->curr = is_target ?
1379 &xt[trav->nfproto].target : &xt[trav->nfproto].match;
1380 trav->class = next_class[trav->class];
1381 break;
1382 case MTTG_TRAV_NFP_SPEC:
1383 trav->curr = trav->curr->next;
1384 if (trav->curr != trav->head)
1385 break;
1386 /* fallthru, _stop will unlock */
1387 default:
1388 return NULL;
1389 }
1390
1391 if (ppos != NULL)
1392 ++*ppos;
1393 return trav;
1394 }
1395
xt_mttg_seq_start(struct seq_file * seq,loff_t * pos,bool is_target)1396 static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
1397 bool is_target)
1398 {
1399 struct nf_mttg_trav *trav = seq->private;
1400 unsigned int j;
1401
1402 trav->class = MTTG_TRAV_INIT;
1403 for (j = 0; j < *pos; ++j)
1404 if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
1405 return NULL;
1406 return trav;
1407 }
1408
xt_mttg_seq_stop(struct seq_file * seq,void * v)1409 static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
1410 {
1411 struct nf_mttg_trav *trav = seq->private;
1412
1413 switch (trav->class) {
1414 case MTTG_TRAV_NFP_UNSPEC:
1415 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1416 break;
1417 case MTTG_TRAV_NFP_SPEC:
1418 mutex_unlock(&xt[trav->nfproto].mutex);
1419 break;
1420 }
1421 }
1422
xt_match_seq_start(struct seq_file * seq,loff_t * pos)1423 static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
1424 {
1425 return xt_mttg_seq_start(seq, pos, false);
1426 }
1427
xt_match_seq_next(struct seq_file * seq,void * v,loff_t * ppos)1428 static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1429 {
1430 return xt_mttg_seq_next(seq, v, ppos, false);
1431 }
1432
xt_match_seq_show(struct seq_file * seq,void * v)1433 static int xt_match_seq_show(struct seq_file *seq, void *v)
1434 {
1435 const struct nf_mttg_trav *trav = seq->private;
1436 const struct xt_match *match;
1437
1438 switch (trav->class) {
1439 case MTTG_TRAV_NFP_UNSPEC:
1440 case MTTG_TRAV_NFP_SPEC:
1441 if (trav->curr == trav->head)
1442 return 0;
1443 match = list_entry(trav->curr, struct xt_match, list);
1444 if (*match->name)
1445 seq_printf(seq, "%s\n", match->name);
1446 }
1447 return 0;
1448 }
1449
1450 static const struct seq_operations xt_match_seq_ops = {
1451 .start = xt_match_seq_start,
1452 .next = xt_match_seq_next,
1453 .stop = xt_mttg_seq_stop,
1454 .show = xt_match_seq_show,
1455 };
1456
xt_match_open(struct inode * inode,struct file * file)1457 static int xt_match_open(struct inode *inode, struct file *file)
1458 {
1459 struct nf_mttg_trav *trav;
1460 trav = __seq_open_private(file, &xt_match_seq_ops, sizeof(*trav));
1461 if (!trav)
1462 return -ENOMEM;
1463
1464 trav->nfproto = (unsigned long)PDE_DATA(inode);
1465 return 0;
1466 }
1467
1468 static const struct file_operations xt_match_ops = {
1469 .owner = THIS_MODULE,
1470 .open = xt_match_open,
1471 .read = seq_read,
1472 .llseek = seq_lseek,
1473 .release = seq_release_private,
1474 };
1475
xt_target_seq_start(struct seq_file * seq,loff_t * pos)1476 static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
1477 {
1478 return xt_mttg_seq_start(seq, pos, true);
1479 }
1480
xt_target_seq_next(struct seq_file * seq,void * v,loff_t * ppos)1481 static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1482 {
1483 return xt_mttg_seq_next(seq, v, ppos, true);
1484 }
1485
xt_target_seq_show(struct seq_file * seq,void * v)1486 static int xt_target_seq_show(struct seq_file *seq, void *v)
1487 {
1488 const struct nf_mttg_trav *trav = seq->private;
1489 const struct xt_target *target;
1490
1491 switch (trav->class) {
1492 case MTTG_TRAV_NFP_UNSPEC:
1493 case MTTG_TRAV_NFP_SPEC:
1494 if (trav->curr == trav->head)
1495 return 0;
1496 target = list_entry(trav->curr, struct xt_target, list);
1497 if (*target->name)
1498 seq_printf(seq, "%s\n", target->name);
1499 }
1500 return 0;
1501 }
1502
1503 static const struct seq_operations xt_target_seq_ops = {
1504 .start = xt_target_seq_start,
1505 .next = xt_target_seq_next,
1506 .stop = xt_mttg_seq_stop,
1507 .show = xt_target_seq_show,
1508 };
1509
xt_target_open(struct inode * inode,struct file * file)1510 static int xt_target_open(struct inode *inode, struct file *file)
1511 {
1512 struct nf_mttg_trav *trav;
1513 trav = __seq_open_private(file, &xt_target_seq_ops, sizeof(*trav));
1514 if (!trav)
1515 return -ENOMEM;
1516
1517 trav->nfproto = (unsigned long)PDE_DATA(inode);
1518 return 0;
1519 }
1520
1521 static const struct file_operations xt_target_ops = {
1522 .owner = THIS_MODULE,
1523 .open = xt_target_open,
1524 .read = seq_read,
1525 .llseek = seq_lseek,
1526 .release = seq_release_private,
1527 };
1528
1529 #define FORMAT_TABLES "_tables_names"
1530 #define FORMAT_MATCHES "_tables_matches"
1531 #define FORMAT_TARGETS "_tables_targets"
1532
1533 #endif /* CONFIG_PROC_FS */
1534
1535 /**
1536 * xt_hook_ops_alloc - set up hooks for a new table
1537 * @table: table with metadata needed to set up hooks
1538 * @fn: Hook function
1539 *
1540 * This function will create the nf_hook_ops that the x_table needs
1541 * to hand to xt_hook_link_net().
1542 */
1543 struct nf_hook_ops *
xt_hook_ops_alloc(const struct xt_table * table,nf_hookfn * fn)1544 xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn)
1545 {
1546 unsigned int hook_mask = table->valid_hooks;
1547 uint8_t i, num_hooks = hweight32(hook_mask);
1548 uint8_t hooknum;
1549 struct nf_hook_ops *ops;
1550
1551 if (!num_hooks)
1552 return ERR_PTR(-EINVAL);
1553
1554 ops = kcalloc(num_hooks, sizeof(*ops), GFP_KERNEL);
1555 if (ops == NULL)
1556 return ERR_PTR(-ENOMEM);
1557
1558 for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0;
1559 hook_mask >>= 1, ++hooknum) {
1560 if (!(hook_mask & 1))
1561 continue;
1562 ops[i].hook = fn;
1563 ops[i].pf = table->af;
1564 ops[i].hooknum = hooknum;
1565 ops[i].priority = table->priority;
1566 ++i;
1567 }
1568
1569 return ops;
1570 }
1571 EXPORT_SYMBOL_GPL(xt_hook_ops_alloc);
1572
xt_proto_init(struct net * net,u_int8_t af)1573 int xt_proto_init(struct net *net, u_int8_t af)
1574 {
1575 #ifdef CONFIG_PROC_FS
1576 char buf[XT_FUNCTION_MAXNAMELEN];
1577 struct proc_dir_entry *proc;
1578 kuid_t root_uid;
1579 kgid_t root_gid;
1580 #endif
1581
1582 if (af >= ARRAY_SIZE(xt_prefix))
1583 return -EINVAL;
1584
1585
1586 #ifdef CONFIG_PROC_FS
1587 root_uid = make_kuid(net->user_ns, 0);
1588 root_gid = make_kgid(net->user_ns, 0);
1589
1590 strlcpy(buf, xt_prefix[af], sizeof(buf));
1591 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1592 proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops,
1593 (void *)(unsigned long)af);
1594 if (!proc)
1595 goto out;
1596 if (uid_valid(root_uid) && gid_valid(root_gid))
1597 proc_set_user(proc, root_uid, root_gid);
1598
1599 strlcpy(buf, xt_prefix[af], sizeof(buf));
1600 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1601 proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops,
1602 (void *)(unsigned long)af);
1603 if (!proc)
1604 goto out_remove_tables;
1605 if (uid_valid(root_uid) && gid_valid(root_gid))
1606 proc_set_user(proc, root_uid, root_gid);
1607
1608 strlcpy(buf, xt_prefix[af], sizeof(buf));
1609 strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1610 proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops,
1611 (void *)(unsigned long)af);
1612 if (!proc)
1613 goto out_remove_matches;
1614 if (uid_valid(root_uid) && gid_valid(root_gid))
1615 proc_set_user(proc, root_uid, root_gid);
1616 #endif
1617
1618 return 0;
1619
1620 #ifdef CONFIG_PROC_FS
1621 out_remove_matches:
1622 strlcpy(buf, xt_prefix[af], sizeof(buf));
1623 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1624 remove_proc_entry(buf, net->proc_net);
1625
1626 out_remove_tables:
1627 strlcpy(buf, xt_prefix[af], sizeof(buf));
1628 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1629 remove_proc_entry(buf, net->proc_net);
1630 out:
1631 return -1;
1632 #endif
1633 }
1634 EXPORT_SYMBOL_GPL(xt_proto_init);
1635
xt_proto_fini(struct net * net,u_int8_t af)1636 void xt_proto_fini(struct net *net, u_int8_t af)
1637 {
1638 #ifdef CONFIG_PROC_FS
1639 char buf[XT_FUNCTION_MAXNAMELEN];
1640
1641 strlcpy(buf, xt_prefix[af], sizeof(buf));
1642 strlcat(buf, FORMAT_TABLES, sizeof(buf));
1643 remove_proc_entry(buf, net->proc_net);
1644
1645 strlcpy(buf, xt_prefix[af], sizeof(buf));
1646 strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1647 remove_proc_entry(buf, net->proc_net);
1648
1649 strlcpy(buf, xt_prefix[af], sizeof(buf));
1650 strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1651 remove_proc_entry(buf, net->proc_net);
1652 #endif /*CONFIG_PROC_FS*/
1653 }
1654 EXPORT_SYMBOL_GPL(xt_proto_fini);
1655
1656 /**
1657 * xt_percpu_counter_alloc - allocate x_tables rule counter
1658 *
1659 * @state: pointer to xt_percpu allocation state
1660 * @counter: pointer to counter struct inside the ip(6)/arpt_entry struct
1661 *
1662 * On SMP, the packet counter [ ip(6)t_entry->counters.pcnt ] will then
1663 * contain the address of the real (percpu) counter.
1664 *
1665 * Rule evaluation needs to use xt_get_this_cpu_counter() helper
1666 * to fetch the real percpu counter.
1667 *
1668 * To speed up allocation and improve data locality, a 4kb block is
1669 * allocated.
1670 *
1671 * xt_percpu_counter_alloc_state contains the base address of the
1672 * allocated page and the current sub-offset.
1673 *
1674 * returns false on error.
1675 */
xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state * state,struct xt_counters * counter)1676 bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state,
1677 struct xt_counters *counter)
1678 {
1679 BUILD_BUG_ON(XT_PCPU_BLOCK_SIZE < (sizeof(*counter) * 2));
1680
1681 if (nr_cpu_ids <= 1)
1682 return true;
1683
1684 if (!state->mem) {
1685 state->mem = __alloc_percpu(XT_PCPU_BLOCK_SIZE,
1686 XT_PCPU_BLOCK_SIZE);
1687 if (!state->mem)
1688 return false;
1689 }
1690 counter->pcnt = (__force unsigned long)(state->mem + state->off);
1691 state->off += sizeof(*counter);
1692 if (state->off > (XT_PCPU_BLOCK_SIZE - sizeof(*counter))) {
1693 state->mem = NULL;
1694 state->off = 0;
1695 }
1696 return true;
1697 }
1698 EXPORT_SYMBOL_GPL(xt_percpu_counter_alloc);
1699
xt_percpu_counter_free(struct xt_counters * counters)1700 void xt_percpu_counter_free(struct xt_counters *counters)
1701 {
1702 unsigned long pcnt = counters->pcnt;
1703
1704 if (nr_cpu_ids > 1 && (pcnt & (XT_PCPU_BLOCK_SIZE - 1)) == 0)
1705 free_percpu((void __percpu *)pcnt);
1706 }
1707 EXPORT_SYMBOL_GPL(xt_percpu_counter_free);
1708
xt_net_init(struct net * net)1709 static int __net_init xt_net_init(struct net *net)
1710 {
1711 int i;
1712
1713 for (i = 0; i < NFPROTO_NUMPROTO; i++)
1714 INIT_LIST_HEAD(&net->xt.tables[i]);
1715 return 0;
1716 }
1717
1718 static struct pernet_operations xt_net_ops = {
1719 .init = xt_net_init,
1720 };
1721
xt_init(void)1722 static int __init xt_init(void)
1723 {
1724 unsigned int i;
1725 int rv;
1726
1727 for_each_possible_cpu(i) {
1728 seqcount_init(&per_cpu(xt_recseq, i));
1729 }
1730
1731 xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);
1732 if (!xt)
1733 return -ENOMEM;
1734
1735 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
1736 mutex_init(&xt[i].mutex);
1737 #ifdef CONFIG_COMPAT
1738 mutex_init(&xt[i].compat_mutex);
1739 xt[i].compat_tab = NULL;
1740 #endif
1741 INIT_LIST_HEAD(&xt[i].target);
1742 INIT_LIST_HEAD(&xt[i].match);
1743 }
1744 rv = register_pernet_subsys(&xt_net_ops);
1745 if (rv < 0)
1746 kfree(xt);
1747 return rv;
1748 }
1749
xt_fini(void)1750 static void __exit xt_fini(void)
1751 {
1752 unregister_pernet_subsys(&xt_net_ops);
1753 kfree(xt);
1754 }
1755
1756 module_init(xt_init);
1757 module_exit(xt_fini);
1758
1759