arp_tables.c 39 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Packet matching code for ARP packets.
  4. *
  5. * Based heavily, if not almost entirely, upon ip_tables.c framework.
  6. *
  7. * Some ARP specific bits are:
  8. *
  9. * Copyright (C) 2002 David S. Miller (davem@redhat.com)
  10. * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net>
  11. *
  12. */
  13. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14. #include <linux/kernel.h>
  15. #include <linux/skbuff.h>
  16. #include <linux/netdevice.h>
  17. #include <linux/capability.h>
  18. #include <linux/if_arp.h>
  19. #include <linux/kmod.h>
  20. #include <linux/vmalloc.h>
  21. #include <linux/proc_fs.h>
  22. #include <linux/module.h>
  23. #include <linux/init.h>
  24. #include <linux/mutex.h>
  25. #include <linux/err.h>
  26. #include <net/compat.h>
  27. #include <net/sock.h>
  28. #include <linux/uaccess.h>
  29. #include <linux/netfilter/x_tables.h>
  30. #include <linux/netfilter_arp/arp_tables.h>
  31. #include "../../netfilter/xt_repldata.h"
  32. MODULE_LICENSE("GPL");
  33. MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  34. MODULE_DESCRIPTION("arptables core");
  35. void *arpt_alloc_initial_table(const struct xt_table *info)
  36. {
  37. return xt_alloc_initial_table(arpt, ARPT);
  38. }
  39. EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  40. static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  41. const char *hdr_addr, int len)
  42. {
  43. int i, ret;
  44. if (len > ARPT_DEV_ADDR_LEN_MAX)
  45. len = ARPT_DEV_ADDR_LEN_MAX;
  46. ret = 0;
  47. for (i = 0; i < len; i++)
  48. ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  49. return ret != 0;
  50. }
  51. /*
  52. * Unfortunately, _b and _mask are not aligned to an int (or long int)
  53. * Some arches dont care, unrolling the loop is a win on them.
  54. * For other arches, we only have a 16bit alignement.
  55. */
  56. static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  57. {
  58. #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  59. unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  60. #else
  61. unsigned long ret = 0;
  62. const u16 *a = (const u16 *)_a;
  63. const u16 *b = (const u16 *)_b;
  64. const u16 *mask = (const u16 *)_mask;
  65. int i;
  66. for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  67. ret |= (a[i] ^ b[i]) & mask[i];
  68. #endif
  69. return ret;
  70. }
  71. /* Returns whether packet matches rule or not. */
  72. static inline int arp_packet_match(const struct arphdr *arphdr,
  73. struct net_device *dev,
  74. const char *indev,
  75. const char *outdev,
  76. const struct arpt_arp *arpinfo)
  77. {
  78. const char *arpptr = (char *)(arphdr + 1);
  79. const char *src_devaddr, *tgt_devaddr;
  80. __be32 src_ipaddr, tgt_ipaddr;
  81. long ret;
  82. if (NF_INVF(arpinfo, ARPT_INV_ARPOP,
  83. (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop))
  84. return 0;
  85. if (NF_INVF(arpinfo, ARPT_INV_ARPHRD,
  86. (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd))
  87. return 0;
  88. if (NF_INVF(arpinfo, ARPT_INV_ARPPRO,
  89. (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro))
  90. return 0;
  91. if (NF_INVF(arpinfo, ARPT_INV_ARPHLN,
  92. (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln))
  93. return 0;
  94. src_devaddr = arpptr;
  95. arpptr += dev->addr_len;
  96. memcpy(&src_ipaddr, arpptr, sizeof(u32));
  97. arpptr += sizeof(u32);
  98. tgt_devaddr = arpptr;
  99. arpptr += dev->addr_len;
  100. memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
  101. if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR,
  102. arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr,
  103. dev->addr_len)) ||
  104. NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR,
  105. arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr,
  106. dev->addr_len)))
  107. return 0;
  108. if (NF_INVF(arpinfo, ARPT_INV_SRCIP,
  109. (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) ||
  110. NF_INVF(arpinfo, ARPT_INV_TGTIP,
  111. (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr))
  112. return 0;
  113. /* Look for ifname matches. */
  114. ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
  115. if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0))
  116. return 0;
  117. ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
  118. if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0))
  119. return 0;
  120. return 1;
  121. }
  122. static inline int arp_checkentry(const struct arpt_arp *arp)
  123. {
  124. if (arp->flags & ~ARPT_F_MASK)
  125. return 0;
  126. if (arp->invflags & ~ARPT_INV_MASK)
  127. return 0;
  128. return 1;
  129. }
  130. static unsigned int
  131. arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
  132. {
  133. net_err_ratelimited("arp_tables: error: '%s'\n",
  134. (const char *)par->targinfo);
  135. return NF_DROP;
  136. }
  137. static inline const struct xt_entry_target *
  138. arpt_get_target_c(const struct arpt_entry *e)
  139. {
  140. return arpt_get_target((struct arpt_entry *)e);
  141. }
  142. static inline struct arpt_entry *
  143. get_entry(const void *base, unsigned int offset)
  144. {
  145. return (struct arpt_entry *)(base + offset);
  146. }
  147. static inline
  148. struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
  149. {
  150. return (void *)entry + entry->next_offset;
  151. }
  152. unsigned int arpt_do_table(struct sk_buff *skb,
  153. const struct nf_hook_state *state,
  154. struct xt_table *table)
  155. {
  156. unsigned int hook = state->hook;
  157. static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
  158. unsigned int verdict = NF_DROP;
  159. const struct arphdr *arp;
  160. struct arpt_entry *e, **jumpstack;
  161. const char *indev, *outdev;
  162. const void *table_base;
  163. unsigned int cpu, stackidx = 0;
  164. const struct xt_table_info *private;
  165. struct xt_action_param acpar;
  166. unsigned int addend;
  167. if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
  168. return NF_DROP;
  169. indev = state->in ? state->in->name : nulldevname;
  170. outdev = state->out ? state->out->name : nulldevname;
  171. local_bh_disable();
  172. addend = xt_write_recseq_begin();
  173. private = READ_ONCE(table->private); /* Address dependency. */
  174. cpu = smp_processor_id();
  175. table_base = private->entries;
  176. jumpstack = (struct arpt_entry **)private->jumpstack[cpu];
  177. /* No TEE support for arptables, so no need to switch to alternate
  178. * stack. All targets that reenter must return absolute verdicts.
  179. */
  180. e = get_entry(table_base, private->hook_entry[hook]);
  181. acpar.state = state;
  182. acpar.hotdrop = false;
  183. arp = arp_hdr(skb);
  184. do {
  185. const struct xt_entry_target *t;
  186. struct xt_counters *counter;
  187. if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
  188. e = arpt_next_entry(e);
  189. continue;
  190. }
  191. counter = xt_get_this_cpu_counter(&e->counters);
  192. ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1);
  193. t = arpt_get_target_c(e);
  194. /* Standard target? */
  195. if (!t->u.kernel.target->target) {
  196. int v;
  197. v = ((struct xt_standard_target *)t)->verdict;
  198. if (v < 0) {
  199. /* Pop from stack? */
  200. if (v != XT_RETURN) {
  201. verdict = (unsigned int)(-v) - 1;
  202. break;
  203. }
  204. if (stackidx == 0) {
  205. e = get_entry(table_base,
  206. private->underflow[hook]);
  207. } else {
  208. e = jumpstack[--stackidx];
  209. e = arpt_next_entry(e);
  210. }
  211. continue;
  212. }
  213. if (table_base + v
  214. != arpt_next_entry(e)) {
  215. if (unlikely(stackidx >= private->stacksize)) {
  216. verdict = NF_DROP;
  217. break;
  218. }
  219. jumpstack[stackidx++] = e;
  220. }
  221. e = get_entry(table_base, v);
  222. continue;
  223. }
  224. acpar.target = t->u.kernel.target;
  225. acpar.targinfo = t->data;
  226. verdict = t->u.kernel.target->target(skb, &acpar);
  227. if (verdict == XT_CONTINUE) {
  228. /* Target might have changed stuff. */
  229. arp = arp_hdr(skb);
  230. e = arpt_next_entry(e);
  231. } else {
  232. /* Verdict */
  233. break;
  234. }
  235. } while (!acpar.hotdrop);
  236. xt_write_recseq_end(addend);
  237. local_bh_enable();
  238. if (acpar.hotdrop)
  239. return NF_DROP;
  240. else
  241. return verdict;
  242. }
  243. /* All zeroes == unconditional rule. */
  244. static inline bool unconditional(const struct arpt_entry *e)
  245. {
  246. static const struct arpt_arp uncond;
  247. return e->target_offset == sizeof(struct arpt_entry) &&
  248. memcmp(&e->arp, &uncond, sizeof(uncond)) == 0;
  249. }
  250. /* Figures out from what hook each rule can be called: returns 0 if
  251. * there are loops. Puts hook bitmask in comefrom.
  252. */
  253. static int mark_source_chains(const struct xt_table_info *newinfo,
  254. unsigned int valid_hooks, void *entry0,
  255. unsigned int *offsets)
  256. {
  257. unsigned int hook;
  258. /* No recursion; use packet counter to save back ptrs (reset
  259. * to 0 as we leave), and comefrom to save source hook bitmask.
  260. */
  261. for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
  262. unsigned int pos = newinfo->hook_entry[hook];
  263. struct arpt_entry *e = entry0 + pos;
  264. if (!(valid_hooks & (1 << hook)))
  265. continue;
  266. /* Set initial back pointer. */
  267. e->counters.pcnt = pos;
  268. for (;;) {
  269. const struct xt_standard_target *t
  270. = (void *)arpt_get_target_c(e);
  271. int visited = e->comefrom & (1 << hook);
  272. if (e->comefrom & (1 << NF_ARP_NUMHOOKS))
  273. return 0;
  274. e->comefrom
  275. |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
  276. /* Unconditional return/END. */
  277. if ((unconditional(e) &&
  278. (strcmp(t->target.u.user.name,
  279. XT_STANDARD_TARGET) == 0) &&
  280. t->verdict < 0) || visited) {
  281. unsigned int oldpos, size;
  282. /* Return: backtrack through the last
  283. * big jump.
  284. */
  285. do {
  286. e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
  287. oldpos = pos;
  288. pos = e->counters.pcnt;
  289. e->counters.pcnt = 0;
  290. /* We're at the start. */
  291. if (pos == oldpos)
  292. goto next;
  293. e = entry0 + pos;
  294. } while (oldpos == pos + e->next_offset);
  295. /* Move along one */
  296. size = e->next_offset;
  297. e = entry0 + pos + size;
  298. if (pos + size >= newinfo->size)
  299. return 0;
  300. e->counters.pcnt = pos;
  301. pos += size;
  302. } else {
  303. int newpos = t->verdict;
  304. if (strcmp(t->target.u.user.name,
  305. XT_STANDARD_TARGET) == 0 &&
  306. newpos >= 0) {
  307. /* This a jump; chase it. */
  308. if (!xt_find_jump_offset(offsets, newpos,
  309. newinfo->number))
  310. return 0;
  311. } else {
  312. /* ... this is a fallthru */
  313. newpos = pos + e->next_offset;
  314. if (newpos >= newinfo->size)
  315. return 0;
  316. }
  317. e = entry0 + newpos;
  318. e->counters.pcnt = pos;
  319. pos = newpos;
  320. }
  321. }
  322. next: ;
  323. }
  324. return 1;
  325. }
  326. static int check_target(struct arpt_entry *e, struct net *net, const char *name)
  327. {
  328. struct xt_entry_target *t = arpt_get_target(e);
  329. struct xt_tgchk_param par = {
  330. .net = net,
  331. .table = name,
  332. .entryinfo = e,
  333. .target = t->u.kernel.target,
  334. .targinfo = t->data,
  335. .hook_mask = e->comefrom,
  336. .family = NFPROTO_ARP,
  337. };
  338. return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  339. }
  340. static int
  341. find_check_entry(struct arpt_entry *e, struct net *net, const char *name,
  342. unsigned int size,
  343. struct xt_percpu_counter_alloc_state *alloc_state)
  344. {
  345. struct xt_entry_target *t;
  346. struct xt_target *target;
  347. int ret;
  348. if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
  349. return -ENOMEM;
  350. t = arpt_get_target(e);
  351. target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
  352. t->u.user.revision);
  353. if (IS_ERR(target)) {
  354. ret = PTR_ERR(target);
  355. goto out;
  356. }
  357. t->u.kernel.target = target;
  358. ret = check_target(e, net, name);
  359. if (ret)
  360. goto err;
  361. return 0;
  362. err:
  363. module_put(t->u.kernel.target->me);
  364. out:
  365. xt_percpu_counter_free(&e->counters);
  366. return ret;
  367. }
  368. static bool check_underflow(const struct arpt_entry *e)
  369. {
  370. const struct xt_entry_target *t;
  371. unsigned int verdict;
  372. if (!unconditional(e))
  373. return false;
  374. t = arpt_get_target_c(e);
  375. if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
  376. return false;
  377. verdict = ((struct xt_standard_target *)t)->verdict;
  378. verdict = -verdict - 1;
  379. return verdict == NF_DROP || verdict == NF_ACCEPT;
  380. }
  381. static inline int check_entry_size_and_hooks(struct arpt_entry *e,
  382. struct xt_table_info *newinfo,
  383. const unsigned char *base,
  384. const unsigned char *limit,
  385. const unsigned int *hook_entries,
  386. const unsigned int *underflows,
  387. unsigned int valid_hooks)
  388. {
  389. unsigned int h;
  390. int err;
  391. if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
  392. (unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
  393. (unsigned char *)e + e->next_offset > limit)
  394. return -EINVAL;
  395. if (e->next_offset
  396. < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target))
  397. return -EINVAL;
  398. if (!arp_checkentry(&e->arp))
  399. return -EINVAL;
  400. err = xt_check_entry_offsets(e, e->elems, e->target_offset,
  401. e->next_offset);
  402. if (err)
  403. return err;
  404. /* Check hooks & underflows */
  405. for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
  406. if (!(valid_hooks & (1 << h)))
  407. continue;
  408. if ((unsigned char *)e - base == hook_entries[h])
  409. newinfo->hook_entry[h] = hook_entries[h];
  410. if ((unsigned char *)e - base == underflows[h]) {
  411. if (!check_underflow(e))
  412. return -EINVAL;
  413. newinfo->underflow[h] = underflows[h];
  414. }
  415. }
  416. /* Clear counters and comefrom */
  417. e->counters = ((struct xt_counters) { 0, 0 });
  418. e->comefrom = 0;
  419. return 0;
  420. }
  421. static void cleanup_entry(struct arpt_entry *e, struct net *net)
  422. {
  423. struct xt_tgdtor_param par;
  424. struct xt_entry_target *t;
  425. t = arpt_get_target(e);
  426. par.net = net;
  427. par.target = t->u.kernel.target;
  428. par.targinfo = t->data;
  429. par.family = NFPROTO_ARP;
  430. if (par.target->destroy != NULL)
  431. par.target->destroy(&par);
  432. module_put(par.target->me);
  433. xt_percpu_counter_free(&e->counters);
  434. }
  435. /* Checks and translates the user-supplied table segment (held in
  436. * newinfo).
  437. */
  438. static int translate_table(struct net *net,
  439. struct xt_table_info *newinfo,
  440. void *entry0,
  441. const struct arpt_replace *repl)
  442. {
  443. struct xt_percpu_counter_alloc_state alloc_state = { 0 };
  444. struct arpt_entry *iter;
  445. unsigned int *offsets;
  446. unsigned int i;
  447. int ret = 0;
  448. newinfo->size = repl->size;
  449. newinfo->number = repl->num_entries;
  450. /* Init all hooks to impossible value. */
  451. for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
  452. newinfo->hook_entry[i] = 0xFFFFFFFF;
  453. newinfo->underflow[i] = 0xFFFFFFFF;
  454. }
  455. offsets = xt_alloc_entry_offsets(newinfo->number);
  456. if (!offsets)
  457. return -ENOMEM;
  458. i = 0;
  459. /* Walk through entries, checking offsets. */
  460. xt_entry_foreach(iter, entry0, newinfo->size) {
  461. ret = check_entry_size_and_hooks(iter, newinfo, entry0,
  462. entry0 + repl->size,
  463. repl->hook_entry,
  464. repl->underflow,
  465. repl->valid_hooks);
  466. if (ret != 0)
  467. goto out_free;
  468. if (i < repl->num_entries)
  469. offsets[i] = (void *)iter - entry0;
  470. ++i;
  471. if (strcmp(arpt_get_target(iter)->u.user.name,
  472. XT_ERROR_TARGET) == 0)
  473. ++newinfo->stacksize;
  474. }
  475. ret = -EINVAL;
  476. if (i != repl->num_entries)
  477. goto out_free;
  478. ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
  479. if (ret)
  480. goto out_free;
  481. if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
  482. ret = -ELOOP;
  483. goto out_free;
  484. }
  485. kvfree(offsets);
  486. /* Finally, each sanity check must pass */
  487. i = 0;
  488. xt_entry_foreach(iter, entry0, newinfo->size) {
  489. ret = find_check_entry(iter, net, repl->name, repl->size,
  490. &alloc_state);
  491. if (ret != 0)
  492. break;
  493. ++i;
  494. }
  495. if (ret != 0) {
  496. xt_entry_foreach(iter, entry0, newinfo->size) {
  497. if (i-- == 0)
  498. break;
  499. cleanup_entry(iter, net);
  500. }
  501. return ret;
  502. }
  503. return ret;
  504. out_free:
  505. kvfree(offsets);
  506. return ret;
  507. }
  508. static void get_counters(const struct xt_table_info *t,
  509. struct xt_counters counters[])
  510. {
  511. struct arpt_entry *iter;
  512. unsigned int cpu;
  513. unsigned int i;
  514. for_each_possible_cpu(cpu) {
  515. seqcount_t *s = &per_cpu(xt_recseq, cpu);
  516. i = 0;
  517. xt_entry_foreach(iter, t->entries, t->size) {
  518. struct xt_counters *tmp;
  519. u64 bcnt, pcnt;
  520. unsigned int start;
  521. tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
  522. do {
  523. start = read_seqcount_begin(s);
  524. bcnt = tmp->bcnt;
  525. pcnt = tmp->pcnt;
  526. } while (read_seqcount_retry(s, start));
  527. ADD_COUNTER(counters[i], bcnt, pcnt);
  528. ++i;
  529. cond_resched();
  530. }
  531. }
  532. }
  533. static void get_old_counters(const struct xt_table_info *t,
  534. struct xt_counters counters[])
  535. {
  536. struct arpt_entry *iter;
  537. unsigned int cpu, i;
  538. for_each_possible_cpu(cpu) {
  539. i = 0;
  540. xt_entry_foreach(iter, t->entries, t->size) {
  541. struct xt_counters *tmp;
  542. tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
  543. ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
  544. ++i;
  545. }
  546. cond_resched();
  547. }
  548. }
  549. static struct xt_counters *alloc_counters(const struct xt_table *table)
  550. {
  551. unsigned int countersize;
  552. struct xt_counters *counters;
  553. const struct xt_table_info *private = table->private;
  554. /* We need atomic snapshot of counters: rest doesn't change
  555. * (other than comefrom, which userspace doesn't care
  556. * about).
  557. */
  558. countersize = sizeof(struct xt_counters) * private->number;
  559. counters = vzalloc(countersize);
  560. if (counters == NULL)
  561. return ERR_PTR(-ENOMEM);
  562. get_counters(private, counters);
  563. return counters;
  564. }
  565. static int copy_entries_to_user(unsigned int total_size,
  566. const struct xt_table *table,
  567. void __user *userptr)
  568. {
  569. unsigned int off, num;
  570. const struct arpt_entry *e;
  571. struct xt_counters *counters;
  572. struct xt_table_info *private = table->private;
  573. int ret = 0;
  574. void *loc_cpu_entry;
  575. counters = alloc_counters(table);
  576. if (IS_ERR(counters))
  577. return PTR_ERR(counters);
  578. loc_cpu_entry = private->entries;
  579. /* FIXME: use iterator macros --RR */
  580. /* ... then go back and fix counters and names */
  581. for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
  582. const struct xt_entry_target *t;
  583. e = loc_cpu_entry + off;
  584. if (copy_to_user(userptr + off, e, sizeof(*e))) {
  585. ret = -EFAULT;
  586. goto free_counters;
  587. }
  588. if (copy_to_user(userptr + off
  589. + offsetof(struct arpt_entry, counters),
  590. &counters[num],
  591. sizeof(counters[num])) != 0) {
  592. ret = -EFAULT;
  593. goto free_counters;
  594. }
  595. t = arpt_get_target_c(e);
  596. if (xt_target_to_user(t, userptr + off + e->target_offset)) {
  597. ret = -EFAULT;
  598. goto free_counters;
  599. }
  600. }
  601. free_counters:
  602. vfree(counters);
  603. return ret;
  604. }
  605. #ifdef CONFIG_COMPAT
  606. static void compat_standard_from_user(void *dst, const void *src)
  607. {
  608. int v = *(compat_int_t *)src;
  609. if (v > 0)
  610. v += xt_compat_calc_jump(NFPROTO_ARP, v);
  611. memcpy(dst, &v, sizeof(v));
  612. }
  613. static int compat_standard_to_user(void __user *dst, const void *src)
  614. {
  615. compat_int_t cv = *(int *)src;
  616. if (cv > 0)
  617. cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
  618. return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
  619. }
  620. static int compat_calc_entry(const struct arpt_entry *e,
  621. const struct xt_table_info *info,
  622. const void *base, struct xt_table_info *newinfo)
  623. {
  624. const struct xt_entry_target *t;
  625. unsigned int entry_offset;
  626. int off, i, ret;
  627. off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
  628. entry_offset = (void *)e - base;
  629. t = arpt_get_target_c(e);
  630. off += xt_compat_target_offset(t->u.kernel.target);
  631. newinfo->size -= off;
  632. ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
  633. if (ret)
  634. return ret;
  635. for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
  636. if (info->hook_entry[i] &&
  637. (e < (struct arpt_entry *)(base + info->hook_entry[i])))
  638. newinfo->hook_entry[i] -= off;
  639. if (info->underflow[i] &&
  640. (e < (struct arpt_entry *)(base + info->underflow[i])))
  641. newinfo->underflow[i] -= off;
  642. }
  643. return 0;
  644. }
  645. static int compat_table_info(const struct xt_table_info *info,
  646. struct xt_table_info *newinfo)
  647. {
  648. struct arpt_entry *iter;
  649. const void *loc_cpu_entry;
  650. int ret;
  651. if (!newinfo || !info)
  652. return -EINVAL;
  653. /* we dont care about newinfo->entries */
  654. memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
  655. newinfo->initial_entries = 0;
  656. loc_cpu_entry = info->entries;
  657. ret = xt_compat_init_offsets(NFPROTO_ARP, info->number);
  658. if (ret)
  659. return ret;
  660. xt_entry_foreach(iter, loc_cpu_entry, info->size) {
  661. ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
  662. if (ret != 0)
  663. return ret;
  664. }
  665. return 0;
  666. }
  667. #endif
  668. static int get_info(struct net *net, void __user *user, const int *len)
  669. {
  670. char name[XT_TABLE_MAXNAMELEN];
  671. struct xt_table *t;
  672. int ret;
  673. if (*len != sizeof(struct arpt_getinfo))
  674. return -EINVAL;
  675. if (copy_from_user(name, user, sizeof(name)) != 0)
  676. return -EFAULT;
  677. name[XT_TABLE_MAXNAMELEN-1] = '\0';
  678. #ifdef CONFIG_COMPAT
  679. if (in_compat_syscall())
  680. xt_compat_lock(NFPROTO_ARP);
  681. #endif
  682. t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
  683. if (!IS_ERR(t)) {
  684. struct arpt_getinfo info;
  685. const struct xt_table_info *private = t->private;
  686. #ifdef CONFIG_COMPAT
  687. struct xt_table_info tmp;
  688. if (in_compat_syscall()) {
  689. ret = compat_table_info(private, &tmp);
  690. xt_compat_flush_offsets(NFPROTO_ARP);
  691. private = &tmp;
  692. }
  693. #endif
  694. memset(&info, 0, sizeof(info));
  695. info.valid_hooks = t->valid_hooks;
  696. memcpy(info.hook_entry, private->hook_entry,
  697. sizeof(info.hook_entry));
  698. memcpy(info.underflow, private->underflow,
  699. sizeof(info.underflow));
  700. info.num_entries = private->number;
  701. info.size = private->size;
  702. strcpy(info.name, name);
  703. if (copy_to_user(user, &info, *len) != 0)
  704. ret = -EFAULT;
  705. else
  706. ret = 0;
  707. xt_table_unlock(t);
  708. module_put(t->me);
  709. } else
  710. ret = PTR_ERR(t);
  711. #ifdef CONFIG_COMPAT
  712. if (in_compat_syscall())
  713. xt_compat_unlock(NFPROTO_ARP);
  714. #endif
  715. return ret;
  716. }
  717. static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
  718. const int *len)
  719. {
  720. int ret;
  721. struct arpt_get_entries get;
  722. struct xt_table *t;
  723. if (*len < sizeof(get))
  724. return -EINVAL;
  725. if (copy_from_user(&get, uptr, sizeof(get)) != 0)
  726. return -EFAULT;
  727. if (*len != sizeof(struct arpt_get_entries) + get.size)
  728. return -EINVAL;
  729. get.name[sizeof(get.name) - 1] = '\0';
  730. t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
  731. if (!IS_ERR(t)) {
  732. const struct xt_table_info *private = t->private;
  733. if (get.size == private->size)
  734. ret = copy_entries_to_user(private->size,
  735. t, uptr->entrytable);
  736. else
  737. ret = -EAGAIN;
  738. module_put(t->me);
  739. xt_table_unlock(t);
  740. } else
  741. ret = PTR_ERR(t);
  742. return ret;
  743. }
  744. static int __do_replace(struct net *net, const char *name,
  745. unsigned int valid_hooks,
  746. struct xt_table_info *newinfo,
  747. unsigned int num_counters,
  748. void __user *counters_ptr)
  749. {
  750. int ret;
  751. struct xt_table *t;
  752. struct xt_table_info *oldinfo;
  753. struct xt_counters *counters;
  754. void *loc_cpu_old_entry;
  755. struct arpt_entry *iter;
  756. ret = 0;
  757. counters = xt_counters_alloc(num_counters);
  758. if (!counters) {
  759. ret = -ENOMEM;
  760. goto out;
  761. }
  762. t = xt_request_find_table_lock(net, NFPROTO_ARP, name);
  763. if (IS_ERR(t)) {
  764. ret = PTR_ERR(t);
  765. goto free_newinfo_counters_untrans;
  766. }
  767. /* You lied! */
  768. if (valid_hooks != t->valid_hooks) {
  769. ret = -EINVAL;
  770. goto put_module;
  771. }
  772. oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
  773. if (!oldinfo)
  774. goto put_module;
  775. /* Update module usage count based on number of rules */
  776. if ((oldinfo->number > oldinfo->initial_entries) ||
  777. (newinfo->number <= oldinfo->initial_entries))
  778. module_put(t->me);
  779. if ((oldinfo->number > oldinfo->initial_entries) &&
  780. (newinfo->number <= oldinfo->initial_entries))
  781. module_put(t->me);
  782. xt_table_unlock(t);
  783. get_old_counters(oldinfo, counters);
  784. /* Decrease module usage counts and free resource */
  785. loc_cpu_old_entry = oldinfo->entries;
  786. xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
  787. cleanup_entry(iter, net);
  788. xt_free_table_info(oldinfo);
  789. if (copy_to_user(counters_ptr, counters,
  790. sizeof(struct xt_counters) * num_counters) != 0) {
  791. /* Silent error, can't fail, new table is already in place */
  792. net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
  793. }
  794. vfree(counters);
  795. return ret;
  796. put_module:
  797. module_put(t->me);
  798. xt_table_unlock(t);
  799. free_newinfo_counters_untrans:
  800. vfree(counters);
  801. out:
  802. return ret;
  803. }
  804. static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
  805. {
  806. int ret;
  807. struct arpt_replace tmp;
  808. struct xt_table_info *newinfo;
  809. void *loc_cpu_entry;
  810. struct arpt_entry *iter;
  811. if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
  812. return -EFAULT;
  813. /* overflow check */
  814. if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
  815. return -ENOMEM;
  816. if (tmp.num_counters == 0)
  817. return -EINVAL;
  818. tmp.name[sizeof(tmp.name)-1] = 0;
  819. newinfo = xt_alloc_table_info(tmp.size);
  820. if (!newinfo)
  821. return -ENOMEM;
  822. loc_cpu_entry = newinfo->entries;
  823. if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
  824. tmp.size) != 0) {
  825. ret = -EFAULT;
  826. goto free_newinfo;
  827. }
  828. ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
  829. if (ret != 0)
  830. goto free_newinfo;
  831. ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
  832. tmp.num_counters, tmp.counters);
  833. if (ret)
  834. goto free_newinfo_untrans;
  835. return 0;
  836. free_newinfo_untrans:
  837. xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
  838. cleanup_entry(iter, net);
  839. free_newinfo:
  840. xt_free_table_info(newinfo);
  841. return ret;
  842. }
  843. static int do_add_counters(struct net *net, sockptr_t arg, unsigned int len)
  844. {
  845. unsigned int i;
  846. struct xt_counters_info tmp;
  847. struct xt_counters *paddc;
  848. struct xt_table *t;
  849. const struct xt_table_info *private;
  850. int ret = 0;
  851. struct arpt_entry *iter;
  852. unsigned int addend;
  853. paddc = xt_copy_counters(arg, len, &tmp);
  854. if (IS_ERR(paddc))
  855. return PTR_ERR(paddc);
  856. t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
  857. if (IS_ERR(t)) {
  858. ret = PTR_ERR(t);
  859. goto free;
  860. }
  861. local_bh_disable();
  862. private = t->private;
  863. if (private->number != tmp.num_counters) {
  864. ret = -EINVAL;
  865. goto unlock_up_free;
  866. }
  867. i = 0;
  868. addend = xt_write_recseq_begin();
  869. xt_entry_foreach(iter, private->entries, private->size) {
  870. struct xt_counters *tmp;
  871. tmp = xt_get_this_cpu_counter(&iter->counters);
  872. ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
  873. ++i;
  874. }
  875. xt_write_recseq_end(addend);
  876. unlock_up_free:
  877. local_bh_enable();
  878. xt_table_unlock(t);
  879. module_put(t->me);
  880. free:
  881. vfree(paddc);
  882. return ret;
  883. }
  884. #ifdef CONFIG_COMPAT
  885. struct compat_arpt_replace {
  886. char name[XT_TABLE_MAXNAMELEN];
  887. u32 valid_hooks;
  888. u32 num_entries;
  889. u32 size;
  890. u32 hook_entry[NF_ARP_NUMHOOKS];
  891. u32 underflow[NF_ARP_NUMHOOKS];
  892. u32 num_counters;
  893. compat_uptr_t counters;
  894. struct compat_arpt_entry entries[];
  895. };
  896. static inline void compat_release_entry(struct compat_arpt_entry *e)
  897. {
  898. struct xt_entry_target *t;
  899. t = compat_arpt_get_target(e);
  900. module_put(t->u.kernel.target->me);
  901. }
  902. static int
  903. check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
  904. struct xt_table_info *newinfo,
  905. unsigned int *size,
  906. const unsigned char *base,
  907. const unsigned char *limit)
  908. {
  909. struct xt_entry_target *t;
  910. struct xt_target *target;
  911. unsigned int entry_offset;
  912. int ret, off;
  913. if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
  914. (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
  915. (unsigned char *)e + e->next_offset > limit)
  916. return -EINVAL;
  917. if (e->next_offset < sizeof(struct compat_arpt_entry) +
  918. sizeof(struct compat_xt_entry_target))
  919. return -EINVAL;
  920. if (!arp_checkentry(&e->arp))
  921. return -EINVAL;
  922. ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset,
  923. e->next_offset);
  924. if (ret)
  925. return ret;
  926. off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
  927. entry_offset = (void *)e - (void *)base;
  928. t = compat_arpt_get_target(e);
  929. target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
  930. t->u.user.revision);
  931. if (IS_ERR(target)) {
  932. ret = PTR_ERR(target);
  933. goto out;
  934. }
  935. t->u.kernel.target = target;
  936. off += xt_compat_target_offset(target);
  937. *size += off;
  938. ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
  939. if (ret)
  940. goto release_target;
  941. return 0;
  942. release_target:
  943. module_put(t->u.kernel.target->me);
  944. out:
  945. return ret;
  946. }
  947. static void
  948. compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
  949. unsigned int *size,
  950. struct xt_table_info *newinfo, unsigned char *base)
  951. {
  952. struct xt_entry_target *t;
  953. struct arpt_entry *de;
  954. unsigned int origsize;
  955. int h;
  956. origsize = *size;
  957. de = *dstptr;
  958. memcpy(de, e, sizeof(struct arpt_entry));
  959. memcpy(&de->counters, &e->counters, sizeof(e->counters));
  960. *dstptr += sizeof(struct arpt_entry);
  961. *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
  962. de->target_offset = e->target_offset - (origsize - *size);
  963. t = compat_arpt_get_target(e);
  964. xt_compat_target_from_user(t, dstptr, size);
  965. de->next_offset = e->next_offset - (origsize - *size);
  966. for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
  967. if ((unsigned char *)de - base < newinfo->hook_entry[h])
  968. newinfo->hook_entry[h] -= origsize - *size;
  969. if ((unsigned char *)de - base < newinfo->underflow[h])
  970. newinfo->underflow[h] -= origsize - *size;
  971. }
  972. }
  973. static int translate_compat_table(struct net *net,
  974. struct xt_table_info **pinfo,
  975. void **pentry0,
  976. const struct compat_arpt_replace *compatr)
  977. {
  978. unsigned int i, j;
  979. struct xt_table_info *newinfo, *info;
  980. void *pos, *entry0, *entry1;
  981. struct compat_arpt_entry *iter0;
  982. struct arpt_replace repl;
  983. unsigned int size;
  984. int ret;
  985. info = *pinfo;
  986. entry0 = *pentry0;
  987. size = compatr->size;
  988. info->number = compatr->num_entries;
  989. j = 0;
  990. xt_compat_lock(NFPROTO_ARP);
  991. ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries);
  992. if (ret)
  993. goto out_unlock;
  994. /* Walk through entries, checking offsets. */
  995. xt_entry_foreach(iter0, entry0, compatr->size) {
  996. ret = check_compat_entry_size_and_hooks(iter0, info, &size,
  997. entry0,
  998. entry0 + compatr->size);
  999. if (ret != 0)
  1000. goto out_unlock;
  1001. ++j;
  1002. }
  1003. ret = -EINVAL;
  1004. if (j != compatr->num_entries)
  1005. goto out_unlock;
  1006. ret = -ENOMEM;
  1007. newinfo = xt_alloc_table_info(size);
  1008. if (!newinfo)
  1009. goto out_unlock;
  1010. memset(newinfo->entries, 0, size);
  1011. newinfo->number = compatr->num_entries;
  1012. for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
  1013. newinfo->hook_entry[i] = compatr->hook_entry[i];
  1014. newinfo->underflow[i] = compatr->underflow[i];
  1015. }
  1016. entry1 = newinfo->entries;
  1017. pos = entry1;
  1018. size = compatr->size;
  1019. xt_entry_foreach(iter0, entry0, compatr->size)
  1020. compat_copy_entry_from_user(iter0, &pos, &size,
  1021. newinfo, entry1);
  1022. /* all module references in entry0 are now gone */
  1023. xt_compat_flush_offsets(NFPROTO_ARP);
  1024. xt_compat_unlock(NFPROTO_ARP);
  1025. memcpy(&repl, compatr, sizeof(*compatr));
  1026. for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
  1027. repl.hook_entry[i] = newinfo->hook_entry[i];
  1028. repl.underflow[i] = newinfo->underflow[i];
  1029. }
  1030. repl.num_counters = 0;
  1031. repl.counters = NULL;
  1032. repl.size = newinfo->size;
  1033. ret = translate_table(net, newinfo, entry1, &repl);
  1034. if (ret)
  1035. goto free_newinfo;
  1036. *pinfo = newinfo;
  1037. *pentry0 = entry1;
  1038. xt_free_table_info(info);
  1039. return 0;
  1040. free_newinfo:
  1041. xt_free_table_info(newinfo);
  1042. return ret;
  1043. out_unlock:
  1044. xt_compat_flush_offsets(NFPROTO_ARP);
  1045. xt_compat_unlock(NFPROTO_ARP);
  1046. xt_entry_foreach(iter0, entry0, compatr->size) {
  1047. if (j-- == 0)
  1048. break;
  1049. compat_release_entry(iter0);
  1050. }
  1051. return ret;
  1052. }
  1053. static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
  1054. {
  1055. int ret;
  1056. struct compat_arpt_replace tmp;
  1057. struct xt_table_info *newinfo;
  1058. void *loc_cpu_entry;
  1059. struct arpt_entry *iter;
  1060. if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
  1061. return -EFAULT;
  1062. /* overflow check */
  1063. if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
  1064. return -ENOMEM;
  1065. if (tmp.num_counters == 0)
  1066. return -EINVAL;
  1067. tmp.name[sizeof(tmp.name)-1] = 0;
  1068. newinfo = xt_alloc_table_info(tmp.size);
  1069. if (!newinfo)
  1070. return -ENOMEM;
  1071. loc_cpu_entry = newinfo->entries;
  1072. if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
  1073. tmp.size) != 0) {
  1074. ret = -EFAULT;
  1075. goto free_newinfo;
  1076. }
  1077. ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
  1078. if (ret != 0)
  1079. goto free_newinfo;
  1080. ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
  1081. tmp.num_counters, compat_ptr(tmp.counters));
  1082. if (ret)
  1083. goto free_newinfo_untrans;
  1084. return 0;
  1085. free_newinfo_untrans:
  1086. xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
  1087. cleanup_entry(iter, net);
  1088. free_newinfo:
  1089. xt_free_table_info(newinfo);
  1090. return ret;
  1091. }
  1092. static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
  1093. compat_uint_t *size,
  1094. struct xt_counters *counters,
  1095. unsigned int i)
  1096. {
  1097. struct xt_entry_target *t;
  1098. struct compat_arpt_entry __user *ce;
  1099. u_int16_t target_offset, next_offset;
  1100. compat_uint_t origsize;
  1101. int ret;
  1102. origsize = *size;
  1103. ce = *dstptr;
  1104. if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
  1105. copy_to_user(&ce->counters, &counters[i],
  1106. sizeof(counters[i])) != 0)
  1107. return -EFAULT;
  1108. *dstptr += sizeof(struct compat_arpt_entry);
  1109. *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
  1110. target_offset = e->target_offset - (origsize - *size);
  1111. t = arpt_get_target(e);
  1112. ret = xt_compat_target_to_user(t, dstptr, size);
  1113. if (ret)
  1114. return ret;
  1115. next_offset = e->next_offset - (origsize - *size);
  1116. if (put_user(target_offset, &ce->target_offset) != 0 ||
  1117. put_user(next_offset, &ce->next_offset) != 0)
  1118. return -EFAULT;
  1119. return 0;
  1120. }
  1121. static int compat_copy_entries_to_user(unsigned int total_size,
  1122. struct xt_table *table,
  1123. void __user *userptr)
  1124. {
  1125. struct xt_counters *counters;
  1126. const struct xt_table_info *private = table->private;
  1127. void __user *pos;
  1128. unsigned int size;
  1129. int ret = 0;
  1130. unsigned int i = 0;
  1131. struct arpt_entry *iter;
  1132. counters = alloc_counters(table);
  1133. if (IS_ERR(counters))
  1134. return PTR_ERR(counters);
  1135. pos = userptr;
  1136. size = total_size;
  1137. xt_entry_foreach(iter, private->entries, total_size) {
  1138. ret = compat_copy_entry_to_user(iter, &pos,
  1139. &size, counters, i++);
  1140. if (ret != 0)
  1141. break;
  1142. }
  1143. vfree(counters);
  1144. return ret;
  1145. }
  1146. struct compat_arpt_get_entries {
  1147. char name[XT_TABLE_MAXNAMELEN];
  1148. compat_uint_t size;
  1149. struct compat_arpt_entry entrytable[];
  1150. };
  1151. static int compat_get_entries(struct net *net,
  1152. struct compat_arpt_get_entries __user *uptr,
  1153. int *len)
  1154. {
  1155. int ret;
  1156. struct compat_arpt_get_entries get;
  1157. struct xt_table *t;
  1158. if (*len < sizeof(get))
  1159. return -EINVAL;
  1160. if (copy_from_user(&get, uptr, sizeof(get)) != 0)
  1161. return -EFAULT;
  1162. if (*len != sizeof(struct compat_arpt_get_entries) + get.size)
  1163. return -EINVAL;
  1164. get.name[sizeof(get.name) - 1] = '\0';
  1165. xt_compat_lock(NFPROTO_ARP);
  1166. t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
  1167. if (!IS_ERR(t)) {
  1168. const struct xt_table_info *private = t->private;
  1169. struct xt_table_info info;
  1170. ret = compat_table_info(private, &info);
  1171. if (!ret && get.size == info.size) {
  1172. ret = compat_copy_entries_to_user(private->size,
  1173. t, uptr->entrytable);
  1174. } else if (!ret)
  1175. ret = -EAGAIN;
  1176. xt_compat_flush_offsets(NFPROTO_ARP);
  1177. module_put(t->me);
  1178. xt_table_unlock(t);
  1179. } else
  1180. ret = PTR_ERR(t);
  1181. xt_compat_unlock(NFPROTO_ARP);
  1182. return ret;
  1183. }
  1184. #endif
  1185. static int do_arpt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
  1186. unsigned int len)
  1187. {
  1188. int ret;
  1189. if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
  1190. return -EPERM;
  1191. switch (cmd) {
  1192. case ARPT_SO_SET_REPLACE:
  1193. #ifdef CONFIG_COMPAT
  1194. if (in_compat_syscall())
  1195. ret = compat_do_replace(sock_net(sk), arg, len);
  1196. else
  1197. #endif
  1198. ret = do_replace(sock_net(sk), arg, len);
  1199. break;
  1200. case ARPT_SO_SET_ADD_COUNTERS:
  1201. ret = do_add_counters(sock_net(sk), arg, len);
  1202. break;
  1203. default:
  1204. ret = -EINVAL;
  1205. }
  1206. return ret;
  1207. }
  1208. static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
  1209. {
  1210. int ret;
  1211. if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
  1212. return -EPERM;
  1213. switch (cmd) {
  1214. case ARPT_SO_GET_INFO:
  1215. ret = get_info(sock_net(sk), user, len);
  1216. break;
  1217. case ARPT_SO_GET_ENTRIES:
  1218. #ifdef CONFIG_COMPAT
  1219. if (in_compat_syscall())
  1220. ret = compat_get_entries(sock_net(sk), user, len);
  1221. else
  1222. #endif
  1223. ret = get_entries(sock_net(sk), user, len);
  1224. break;
  1225. case ARPT_SO_GET_REVISION_TARGET: {
  1226. struct xt_get_revision rev;
  1227. if (*len != sizeof(rev)) {
  1228. ret = -EINVAL;
  1229. break;
  1230. }
  1231. if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
  1232. ret = -EFAULT;
  1233. break;
  1234. }
  1235. rev.name[sizeof(rev.name)-1] = 0;
  1236. try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
  1237. rev.revision, 1, &ret),
  1238. "arpt_%s", rev.name);
  1239. break;
  1240. }
  1241. default:
  1242. ret = -EINVAL;
  1243. }
  1244. return ret;
  1245. }
  1246. static void __arpt_unregister_table(struct net *net, struct xt_table *table)
  1247. {
  1248. struct xt_table_info *private;
  1249. void *loc_cpu_entry;
  1250. struct module *table_owner = table->me;
  1251. struct arpt_entry *iter;
  1252. private = xt_unregister_table(table);
  1253. /* Decrease module usage counts and free resources */
  1254. loc_cpu_entry = private->entries;
  1255. xt_entry_foreach(iter, loc_cpu_entry, private->size)
  1256. cleanup_entry(iter, net);
  1257. if (private->number > private->initial_entries)
  1258. module_put(table_owner);
  1259. xt_free_table_info(private);
  1260. }
  1261. int arpt_register_table(struct net *net,
  1262. const struct xt_table *table,
  1263. const struct arpt_replace *repl,
  1264. const struct nf_hook_ops *ops,
  1265. struct xt_table **res)
  1266. {
  1267. int ret;
  1268. struct xt_table_info *newinfo;
  1269. struct xt_table_info bootstrap = {0};
  1270. void *loc_cpu_entry;
  1271. struct xt_table *new_table;
  1272. newinfo = xt_alloc_table_info(repl->size);
  1273. if (!newinfo)
  1274. return -ENOMEM;
  1275. loc_cpu_entry = newinfo->entries;
  1276. memcpy(loc_cpu_entry, repl->entries, repl->size);
  1277. ret = translate_table(net, newinfo, loc_cpu_entry, repl);
  1278. if (ret != 0)
  1279. goto out_free;
  1280. new_table = xt_register_table(net, table, &bootstrap, newinfo);
  1281. if (IS_ERR(new_table)) {
  1282. ret = PTR_ERR(new_table);
  1283. goto out_free;
  1284. }
  1285. /* set res now, will see skbs right after nf_register_net_hooks */
  1286. WRITE_ONCE(*res, new_table);
  1287. ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
  1288. if (ret != 0) {
  1289. __arpt_unregister_table(net, new_table);
  1290. *res = NULL;
  1291. }
  1292. return ret;
  1293. out_free:
  1294. xt_free_table_info(newinfo);
  1295. return ret;
  1296. }
  1297. void arpt_unregister_table_pre_exit(struct net *net, struct xt_table *table,
  1298. const struct nf_hook_ops *ops)
  1299. {
  1300. nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
  1301. }
  1302. EXPORT_SYMBOL(arpt_unregister_table_pre_exit);
  1303. void arpt_unregister_table(struct net *net, struct xt_table *table)
  1304. {
  1305. __arpt_unregister_table(net, table);
  1306. }
  1307. /* The built-in targets: standard (NULL) and error. */
  1308. static struct xt_target arpt_builtin_tg[] __read_mostly = {
  1309. {
  1310. .name = XT_STANDARD_TARGET,
  1311. .targetsize = sizeof(int),
  1312. .family = NFPROTO_ARP,
  1313. #ifdef CONFIG_COMPAT
  1314. .compatsize = sizeof(compat_int_t),
  1315. .compat_from_user = compat_standard_from_user,
  1316. .compat_to_user = compat_standard_to_user,
  1317. #endif
  1318. },
  1319. {
  1320. .name = XT_ERROR_TARGET,
  1321. .target = arpt_error,
  1322. .targetsize = XT_FUNCTION_MAXNAMELEN,
  1323. .family = NFPROTO_ARP,
  1324. },
  1325. };
  1326. static struct nf_sockopt_ops arpt_sockopts = {
  1327. .pf = PF_INET,
  1328. .set_optmin = ARPT_BASE_CTL,
  1329. .set_optmax = ARPT_SO_SET_MAX+1,
  1330. .set = do_arpt_set_ctl,
  1331. .get_optmin = ARPT_BASE_CTL,
  1332. .get_optmax = ARPT_SO_GET_MAX+1,
  1333. .get = do_arpt_get_ctl,
  1334. .owner = THIS_MODULE,
  1335. };
  1336. static int __net_init arp_tables_net_init(struct net *net)
  1337. {
  1338. return xt_proto_init(net, NFPROTO_ARP);
  1339. }
  1340. static void __net_exit arp_tables_net_exit(struct net *net)
  1341. {
  1342. xt_proto_fini(net, NFPROTO_ARP);
  1343. }
  1344. static struct pernet_operations arp_tables_net_ops = {
  1345. .init = arp_tables_net_init,
  1346. .exit = arp_tables_net_exit,
  1347. };
  1348. static int __init arp_tables_init(void)
  1349. {
  1350. int ret;
  1351. ret = register_pernet_subsys(&arp_tables_net_ops);
  1352. if (ret < 0)
  1353. goto err1;
  1354. /* No one else will be downing sem now, so we won't sleep */
  1355. ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
  1356. if (ret < 0)
  1357. goto err2;
  1358. /* Register setsockopt */
  1359. ret = nf_register_sockopt(&arpt_sockopts);
  1360. if (ret < 0)
  1361. goto err4;
  1362. return 0;
  1363. err4:
  1364. xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
  1365. err2:
  1366. unregister_pernet_subsys(&arp_tables_net_ops);
  1367. err1:
  1368. return ret;
  1369. }
  1370. static void __exit arp_tables_fini(void)
  1371. {
  1372. nf_unregister_sockopt(&arpt_sockopts);
  1373. xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
  1374. unregister_pernet_subsys(&arp_tables_net_ops);
  1375. }
  1376. EXPORT_SYMBOL(arpt_register_table);
  1377. EXPORT_SYMBOL(arpt_unregister_table);
  1378. EXPORT_SYMBOL(arpt_do_table);
  1379. module_init(arp_tables_init);
  1380. module_exit(arp_tables_fini);