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

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