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

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