| 1 | /* |
| 2 | * Packet matching code for ARP packets. |
| 3 | * |
| 4 | * Based heavily, if not almost entirely, upon ip_tables.c framework. |
| 5 | * |
| 6 | * Some ARP specific bits are: |
| 7 | * |
| 8 | * Copyright (C) 2002 David S. Miller (davem@redhat.com) |
| 9 | * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net> |
| 10 | * |
| 11 | */ |
| 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/skbuff.h> |
| 15 | #include <linux/netdevice.h> |
| 16 | #include <linux/capability.h> |
| 17 | #include <linux/if_arp.h> |
| 18 | #include <linux/kmod.h> |
| 19 | #include <linux/vmalloc.h> |
| 20 | #include <linux/proc_fs.h> |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/mutex.h> |
| 24 | #include <linux/err.h> |
| 25 | #include <net/compat.h> |
| 26 | #include <net/sock.h> |
| 27 | #include <linux/uaccess.h> |
| 28 | |
| 29 | #include <linux/netfilter/x_tables.h> |
| 30 | #include <linux/netfilter_arp/arp_tables.h> |
| 31 | #include "../../netfilter/xt_repldata.h" |
| 32 | |
| 33 | MODULE_LICENSE("GPL"); |
| 34 | MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); |
| 35 | MODULE_DESCRIPTION("arptables core"); |
| 36 | |
| 37 | void *arpt_alloc_initial_table(const struct xt_table *info) |
| 38 | { |
| 39 | return xt_alloc_initial_table(arpt, ARPT); |
| 40 | } |
| 41 | EXPORT_SYMBOL_GPL(arpt_alloc_initial_table); |
| 42 | |
| 43 | static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, |
| 44 | const char *hdr_addr, int len) |
| 45 | { |
| 46 | int i, ret; |
| 47 | |
| 48 | if (len > ARPT_DEV_ADDR_LEN_MAX) |
| 49 | len = ARPT_DEV_ADDR_LEN_MAX; |
| 50 | |
| 51 | ret = 0; |
| 52 | for (i = 0; i < len; i++) |
| 53 | ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i]; |
| 54 | |
| 55 | return ret != 0; |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * Unfortunately, _b and _mask are not aligned to an int (or long int) |
| 60 | * Some arches dont care, unrolling the loop is a win on them. |
| 61 | * For other arches, we only have a 16bit alignement. |
| 62 | */ |
| 63 | static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) |
| 64 | { |
| 65 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 66 | unsigned long ret = ifname_compare_aligned(_a, _b, _mask); |
| 67 | #else |
| 68 | unsigned long ret = 0; |
| 69 | const u16 *a = (const u16 *)_a; |
| 70 | const u16 *b = (const u16 *)_b; |
| 71 | const u16 *mask = (const u16 *)_mask; |
| 72 | int i; |
| 73 | |
| 74 | for (i = 0; i < IFNAMSIZ/sizeof(u16); i++) |
| 75 | ret |= (a[i] ^ b[i]) & mask[i]; |
| 76 | #endif |
| 77 | return ret; |
| 78 | } |
| 79 | |
| 80 | /* Returns whether packet matches rule or not. */ |
| 81 | static inline int arp_packet_match(const struct arphdr *arphdr, |
| 82 | struct net_device *dev, |
| 83 | const char *indev, |
| 84 | const char *outdev, |
| 85 | const struct arpt_arp *arpinfo) |
| 86 | { |
| 87 | const char *arpptr = (char *)(arphdr + 1); |
| 88 | const char *src_devaddr, *tgt_devaddr; |
| 89 | __be32 src_ipaddr, tgt_ipaddr; |
| 90 | long ret; |
| 91 | |
| 92 | if (NF_INVF(arpinfo, ARPT_INV_ARPOP, |
| 93 | (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop)) |
| 94 | return 0; |
| 95 | |
| 96 | if (NF_INVF(arpinfo, ARPT_INV_ARPHRD, |
| 97 | (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd)) |
| 98 | return 0; |
| 99 | |
| 100 | if (NF_INVF(arpinfo, ARPT_INV_ARPPRO, |
| 101 | (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro)) |
| 102 | return 0; |
| 103 | |
| 104 | if (NF_INVF(arpinfo, ARPT_INV_ARPHLN, |
| 105 | (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln)) |
| 106 | return 0; |
| 107 | |
| 108 | src_devaddr = arpptr; |
| 109 | arpptr += dev->addr_len; |
| 110 | memcpy(&src_ipaddr, arpptr, sizeof(u32)); |
| 111 | arpptr += sizeof(u32); |
| 112 | tgt_devaddr = arpptr; |
| 113 | arpptr += dev->addr_len; |
| 114 | memcpy(&tgt_ipaddr, arpptr, sizeof(u32)); |
| 115 | |
| 116 | if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR, |
| 117 | arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, |
| 118 | dev->addr_len)) || |
| 119 | NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR, |
| 120 | arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, |
| 121 | dev->addr_len))) |
| 122 | return 0; |
| 123 | |
| 124 | if (NF_INVF(arpinfo, ARPT_INV_SRCIP, |
| 125 | (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) || |
| 126 | NF_INVF(arpinfo, ARPT_INV_TGTIP, |
| 127 | (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr)) |
| 128 | return 0; |
| 129 | |
| 130 | /* Look for ifname matches. */ |
| 131 | ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask); |
| 132 | |
| 133 | if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0)) |
| 134 | return 0; |
| 135 | |
| 136 | ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask); |
| 137 | |
| 138 | if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0)) |
| 139 | return 0; |
| 140 | |
| 141 | return 1; |
| 142 | } |
| 143 | |
| 144 | static inline int arp_checkentry(const struct arpt_arp *arp) |
| 145 | { |
| 146 | if (arp->flags & ~ARPT_F_MASK) |
| 147 | return 0; |
| 148 | if (arp->invflags & ~ARPT_INV_MASK) |
| 149 | return 0; |
| 150 | |
| 151 | return 1; |
| 152 | } |
| 153 | |
| 154 | static unsigned int |
| 155 | arpt_error(struct sk_buff *skb, const struct xt_action_param *par) |
| 156 | { |
| 157 | net_err_ratelimited("arp_tables: error: '%s'\n", |
| 158 | (const char *)par->targinfo); |
| 159 | |
| 160 | return NF_DROP; |
| 161 | } |
| 162 | |
| 163 | static inline const struct xt_entry_target * |
| 164 | arpt_get_target_c(const struct arpt_entry *e) |
| 165 | { |
| 166 | return arpt_get_target((struct arpt_entry *)e); |
| 167 | } |
| 168 | |
| 169 | static inline struct arpt_entry * |
| 170 | get_entry(const void *base, unsigned int offset) |
| 171 | { |
| 172 | return (struct arpt_entry *)(base + offset); |
| 173 | } |
| 174 | |
| 175 | static inline |
| 176 | struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry) |
| 177 | { |
| 178 | return (void *)entry + entry->next_offset; |
| 179 | } |
| 180 | |
| 181 | unsigned int arpt_do_table(struct sk_buff *skb, |
| 182 | const struct nf_hook_state *state, |
| 183 | struct xt_table *table) |
| 184 | { |
| 185 | unsigned int hook = state->hook; |
| 186 | static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); |
| 187 | unsigned int verdict = NF_DROP; |
| 188 | const struct arphdr *arp; |
| 189 | struct arpt_entry *e, **jumpstack; |
| 190 | const char *indev, *outdev; |
| 191 | const void *table_base; |
| 192 | unsigned int cpu, stackidx = 0; |
| 193 | const struct xt_table_info *private; |
| 194 | struct xt_action_param acpar; |
| 195 | unsigned int addend; |
| 196 | |
| 197 | if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) |
| 198 | return NF_DROP; |
| 199 | |
| 200 | indev = state->in ? state->in->name : nulldevname; |
| 201 | outdev = state->out ? state->out->name : nulldevname; |
| 202 | |
| 203 | local_bh_disable(); |
| 204 | addend = xt_write_recseq_begin(); |
| 205 | private = table->private; |
| 206 | cpu = smp_processor_id(); |
| 207 | /* |
| 208 | * Ensure we load private-> members after we've fetched the base |
| 209 | * pointer. |
| 210 | */ |
| 211 | smp_read_barrier_depends(); |
| 212 | table_base = private->entries; |
| 213 | jumpstack = (struct arpt_entry **)private->jumpstack[cpu]; |
| 214 | |
| 215 | /* No TEE support for arptables, so no need to switch to alternate |
| 216 | * stack. All targets that reenter must return absolute verdicts. |
| 217 | */ |
| 218 | e = get_entry(table_base, private->hook_entry[hook]); |
| 219 | |
| 220 | acpar.state = state; |
| 221 | acpar.hotdrop = false; |
| 222 | |
| 223 | arp = arp_hdr(skb); |
| 224 | do { |
| 225 | const struct xt_entry_target *t; |
| 226 | struct xt_counters *counter; |
| 227 | |
| 228 | if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) { |
| 229 | e = arpt_next_entry(e); |
| 230 | continue; |
| 231 | } |
| 232 | |
| 233 | counter = xt_get_this_cpu_counter(&e->counters); |
| 234 | ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1); |
| 235 | |
| 236 | t = arpt_get_target_c(e); |
| 237 | |
| 238 | /* Standard target? */ |
| 239 | if (!t->u.kernel.target->target) { |
| 240 | int v; |
| 241 | |
| 242 | v = ((struct xt_standard_target *)t)->verdict; |
| 243 | if (v < 0) { |
| 244 | /* Pop from stack? */ |
| 245 | if (v != XT_RETURN) { |
| 246 | verdict = (unsigned int)(-v) - 1; |
| 247 | break; |
| 248 | } |
| 249 | if (stackidx == 0) { |
| 250 | e = get_entry(table_base, |
| 251 | private->underflow[hook]); |
| 252 | } else { |
| 253 | e = jumpstack[--stackidx]; |
| 254 | e = arpt_next_entry(e); |
| 255 | } |
| 256 | continue; |
| 257 | } |
| 258 | if (table_base + v |
| 259 | != arpt_next_entry(e)) { |
| 260 | if (unlikely(stackidx >= private->stacksize)) { |
| 261 | verdict = NF_DROP; |
| 262 | break; |
| 263 | } |
| 264 | jumpstack[stackidx++] = e; |
| 265 | } |
| 266 | |
| 267 | e = get_entry(table_base, v); |
| 268 | continue; |
| 269 | } |
| 270 | |
| 271 | acpar.target = t->u.kernel.target; |
| 272 | acpar.targinfo = t->data; |
| 273 | verdict = t->u.kernel.target->target(skb, &acpar); |
| 274 | |
| 275 | if (verdict == XT_CONTINUE) { |
| 276 | /* Target might have changed stuff. */ |
| 277 | arp = arp_hdr(skb); |
| 278 | e = arpt_next_entry(e); |
| 279 | } else { |
| 280 | /* Verdict */ |
| 281 | break; |
| 282 | } |
| 283 | } while (!acpar.hotdrop); |
| 284 | xt_write_recseq_end(addend); |
| 285 | local_bh_enable(); |
| 286 | |
| 287 | if (acpar.hotdrop) |
| 288 | return NF_DROP; |
| 289 | else |
| 290 | return verdict; |
| 291 | } |
| 292 | |
| 293 | /* All zeroes == unconditional rule. */ |
| 294 | static inline bool unconditional(const struct arpt_entry *e) |
| 295 | { |
| 296 | static const struct arpt_arp uncond; |
| 297 | |
| 298 | return e->target_offset == sizeof(struct arpt_entry) && |
| 299 | memcmp(&e->arp, &uncond, sizeof(uncond)) == 0; |
| 300 | } |
| 301 | |
| 302 | /* Figures out from what hook each rule can be called: returns 0 if |
| 303 | * there are loops. Puts hook bitmask in comefrom. |
| 304 | */ |
| 305 | static int mark_source_chains(const struct xt_table_info *newinfo, |
| 306 | unsigned int valid_hooks, void *entry0, |
| 307 | unsigned int *offsets) |
| 308 | { |
| 309 | unsigned int hook; |
| 310 | |
| 311 | /* No recursion; use packet counter to save back ptrs (reset |
| 312 | * to 0 as we leave), and comefrom to save source hook bitmask. |
| 313 | */ |
| 314 | for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) { |
| 315 | unsigned int pos = newinfo->hook_entry[hook]; |
| 316 | struct arpt_entry *e = entry0 + pos; |
| 317 | |
| 318 | if (!(valid_hooks & (1 << hook))) |
| 319 | continue; |
| 320 | |
| 321 | /* Set initial back pointer. */ |
| 322 | e->counters.pcnt = pos; |
| 323 | |
| 324 | for (;;) { |
| 325 | const struct xt_standard_target *t |
| 326 | = (void *)arpt_get_target_c(e); |
| 327 | int visited = e->comefrom & (1 << hook); |
| 328 | |
| 329 | if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) |
| 330 | return 0; |
| 331 | |
| 332 | e->comefrom |
| 333 | |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS)); |
| 334 | |
| 335 | /* Unconditional return/END. */ |
| 336 | if ((unconditional(e) && |
| 337 | (strcmp(t->target.u.user.name, |
| 338 | XT_STANDARD_TARGET) == 0) && |
| 339 | t->verdict < 0) || visited) { |
| 340 | unsigned int oldpos, size; |
| 341 | |
| 342 | if ((strcmp(t->target.u.user.name, |
| 343 | XT_STANDARD_TARGET) == 0) && |
| 344 | t->verdict < -NF_MAX_VERDICT - 1) |
| 345 | return 0; |
| 346 | |
| 347 | /* Return: backtrack through the last |
| 348 | * big jump. |
| 349 | */ |
| 350 | do { |
| 351 | e->comefrom ^= (1<<NF_ARP_NUMHOOKS); |
| 352 | oldpos = pos; |
| 353 | pos = e->counters.pcnt; |
| 354 | e->counters.pcnt = 0; |
| 355 | |
| 356 | /* We're at the start. */ |
| 357 | if (pos == oldpos) |
| 358 | goto next; |
| 359 | |
| 360 | e = entry0 + pos; |
| 361 | } while (oldpos == pos + e->next_offset); |
| 362 | |
| 363 | /* Move along one */ |
| 364 | size = e->next_offset; |
| 365 | e = entry0 + pos + size; |
| 366 | if (pos + size >= newinfo->size) |
| 367 | return 0; |
| 368 | e->counters.pcnt = pos; |
| 369 | pos += size; |
| 370 | } else { |
| 371 | int newpos = t->verdict; |
| 372 | |
| 373 | if (strcmp(t->target.u.user.name, |
| 374 | XT_STANDARD_TARGET) == 0 && |
| 375 | newpos >= 0) { |
| 376 | /* This a jump; chase it. */ |
| 377 | if (!xt_find_jump_offset(offsets, newpos, |
| 378 | newinfo->number)) |
| 379 | return 0; |
| 380 | e = entry0 + newpos; |
| 381 | } else { |
| 382 | /* ... this is a fallthru */ |
| 383 | newpos = pos + e->next_offset; |
| 384 | if (newpos >= newinfo->size) |
| 385 | return 0; |
| 386 | } |
| 387 | e = entry0 + newpos; |
| 388 | e->counters.pcnt = pos; |
| 389 | pos = newpos; |
| 390 | } |
| 391 | } |
| 392 | next: ; |
| 393 | } |
| 394 | return 1; |
| 395 | } |
| 396 | |
| 397 | static inline int check_target(struct arpt_entry *e, const char *name) |
| 398 | { |
| 399 | struct xt_entry_target *t = arpt_get_target(e); |
| 400 | struct xt_tgchk_param par = { |
| 401 | .table = name, |
| 402 | .entryinfo = e, |
| 403 | .target = t->u.kernel.target, |
| 404 | .targinfo = t->data, |
| 405 | .hook_mask = e->comefrom, |
| 406 | .family = NFPROTO_ARP, |
| 407 | }; |
| 408 | |
| 409 | return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); |
| 410 | } |
| 411 | |
| 412 | static inline int |
| 413 | find_check_entry(struct arpt_entry *e, const char *name, unsigned int size, |
| 414 | struct xt_percpu_counter_alloc_state *alloc_state) |
| 415 | { |
| 416 | struct xt_entry_target *t; |
| 417 | struct xt_target *target; |
| 418 | int ret; |
| 419 | |
| 420 | if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) |
| 421 | return -ENOMEM; |
| 422 | |
| 423 | t = arpt_get_target(e); |
| 424 | target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, |
| 425 | t->u.user.revision); |
| 426 | if (IS_ERR(target)) { |
| 427 | ret = PTR_ERR(target); |
| 428 | goto out; |
| 429 | } |
| 430 | t->u.kernel.target = target; |
| 431 | |
| 432 | ret = check_target(e, name); |
| 433 | if (ret) |
| 434 | goto err; |
| 435 | return 0; |
| 436 | err: |
| 437 | module_put(t->u.kernel.target->me); |
| 438 | out: |
| 439 | xt_percpu_counter_free(&e->counters); |
| 440 | |
| 441 | return ret; |
| 442 | } |
| 443 | |
| 444 | static bool check_underflow(const struct arpt_entry *e) |
| 445 | { |
| 446 | const struct xt_entry_target *t; |
| 447 | unsigned int verdict; |
| 448 | |
| 449 | if (!unconditional(e)) |
| 450 | return false; |
| 451 | t = arpt_get_target_c(e); |
| 452 | if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) |
| 453 | return false; |
| 454 | verdict = ((struct xt_standard_target *)t)->verdict; |
| 455 | verdict = -verdict - 1; |
| 456 | return verdict == NF_DROP || verdict == NF_ACCEPT; |
| 457 | } |
| 458 | |
| 459 | static inline int check_entry_size_and_hooks(struct arpt_entry *e, |
| 460 | struct xt_table_info *newinfo, |
| 461 | const unsigned char *base, |
| 462 | const unsigned char *limit, |
| 463 | const unsigned int *hook_entries, |
| 464 | const unsigned int *underflows, |
| 465 | unsigned int valid_hooks) |
| 466 | { |
| 467 | unsigned int h; |
| 468 | int err; |
| 469 | |
| 470 | if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 || |
| 471 | (unsigned char *)e + sizeof(struct arpt_entry) >= limit || |
| 472 | (unsigned char *)e + e->next_offset > limit) |
| 473 | return -EINVAL; |
| 474 | |
| 475 | if (e->next_offset |
| 476 | < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) |
| 477 | return -EINVAL; |
| 478 | |
| 479 | if (!arp_checkentry(&e->arp)) |
| 480 | return -EINVAL; |
| 481 | |
| 482 | err = xt_check_entry_offsets(e, e->elems, e->target_offset, |
| 483 | e->next_offset); |
| 484 | if (err) |
| 485 | return err; |
| 486 | |
| 487 | /* Check hooks & underflows */ |
| 488 | for (h = 0; h < NF_ARP_NUMHOOKS; h++) { |
| 489 | if (!(valid_hooks & (1 << h))) |
| 490 | continue; |
| 491 | if ((unsigned char *)e - base == hook_entries[h]) |
| 492 | newinfo->hook_entry[h] = hook_entries[h]; |
| 493 | if ((unsigned char *)e - base == underflows[h]) { |
| 494 | if (!check_underflow(e)) |
| 495 | return -EINVAL; |
| 496 | |
| 497 | newinfo->underflow[h] = underflows[h]; |
| 498 | } |
| 499 | } |
| 500 | |
| 501 | /* Clear counters and comefrom */ |
| 502 | e->counters = ((struct xt_counters) { 0, 0 }); |
| 503 | e->comefrom = 0; |
| 504 | return 0; |
| 505 | } |
| 506 | |
| 507 | static inline void cleanup_entry(struct arpt_entry *e) |
| 508 | { |
| 509 | struct xt_tgdtor_param par; |
| 510 | struct xt_entry_target *t; |
| 511 | |
| 512 | t = arpt_get_target(e); |
| 513 | par.target = t->u.kernel.target; |
| 514 | par.targinfo = t->data; |
| 515 | par.family = NFPROTO_ARP; |
| 516 | if (par.target->destroy != NULL) |
| 517 | par.target->destroy(&par); |
| 518 | module_put(par.target->me); |
| 519 | xt_percpu_counter_free(&e->counters); |
| 520 | } |
| 521 | |
| 522 | /* Checks and translates the user-supplied table segment (held in |
| 523 | * newinfo). |
| 524 | */ |
| 525 | static int translate_table(struct xt_table_info *newinfo, void *entry0, |
| 526 | const struct arpt_replace *repl) |
| 527 | { |
| 528 | struct xt_percpu_counter_alloc_state alloc_state = { 0 }; |
| 529 | struct arpt_entry *iter; |
| 530 | unsigned int *offsets; |
| 531 | unsigned int i; |
| 532 | int ret = 0; |
| 533 | |
| 534 | newinfo->size = repl->size; |
| 535 | newinfo->number = repl->num_entries; |
| 536 | |
| 537 | /* Init all hooks to impossible value. */ |
| 538 | for (i = 0; i < NF_ARP_NUMHOOKS; i++) { |
| 539 | newinfo->hook_entry[i] = 0xFFFFFFFF; |
| 540 | newinfo->underflow[i] = 0xFFFFFFFF; |
| 541 | } |
| 542 | |
| 543 | offsets = xt_alloc_entry_offsets(newinfo->number); |
| 544 | if (!offsets) |
| 545 | return -ENOMEM; |
| 546 | i = 0; |
| 547 | |
| 548 | /* Walk through entries, checking offsets. */ |
| 549 | xt_entry_foreach(iter, entry0, newinfo->size) { |
| 550 | ret = check_entry_size_and_hooks(iter, newinfo, entry0, |
| 551 | entry0 + repl->size, |
| 552 | repl->hook_entry, |
| 553 | repl->underflow, |
| 554 | repl->valid_hooks); |
| 555 | if (ret != 0) |
| 556 | goto out_free; |
| 557 | if (i < repl->num_entries) |
| 558 | offsets[i] = (void *)iter - entry0; |
| 559 | ++i; |
| 560 | if (strcmp(arpt_get_target(iter)->u.user.name, |
| 561 | XT_ERROR_TARGET) == 0) |
| 562 | ++newinfo->stacksize; |
| 563 | } |
| 564 | |
| 565 | ret = -EINVAL; |
| 566 | if (i != repl->num_entries) |
| 567 | goto out_free; |
| 568 | |
| 569 | /* Check hooks all assigned */ |
| 570 | for (i = 0; i < NF_ARP_NUMHOOKS; i++) { |
| 571 | /* Only hooks which are valid */ |
| 572 | if (!(repl->valid_hooks & (1 << i))) |
| 573 | continue; |
| 574 | if (newinfo->hook_entry[i] == 0xFFFFFFFF) |
| 575 | goto out_free; |
| 576 | if (newinfo->underflow[i] == 0xFFFFFFFF) |
| 577 | goto out_free; |
| 578 | } |
| 579 | |
| 580 | if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { |
| 581 | ret = -ELOOP; |
| 582 | goto out_free; |
| 583 | } |
| 584 | kvfree(offsets); |
| 585 | |
| 586 | /* Finally, each sanity check must pass */ |
| 587 | i = 0; |
| 588 | xt_entry_foreach(iter, entry0, newinfo->size) { |
| 589 | ret = find_check_entry(iter, repl->name, repl->size, |
| 590 | &alloc_state); |
| 591 | if (ret != 0) |
| 592 | break; |
| 593 | ++i; |
| 594 | } |
| 595 | |
| 596 | if (ret != 0) { |
| 597 | xt_entry_foreach(iter, entry0, newinfo->size) { |
| 598 | if (i-- == 0) |
| 599 | break; |
| 600 | cleanup_entry(iter); |
| 601 | } |
| 602 | return ret; |
| 603 | } |
| 604 | |
| 605 | return ret; |
| 606 | out_free: |
| 607 | kvfree(offsets); |
| 608 | return ret; |
| 609 | } |
| 610 | |
| 611 | static void get_counters(const struct xt_table_info *t, |
| 612 | struct xt_counters counters[]) |
| 613 | { |
| 614 | struct arpt_entry *iter; |
| 615 | unsigned int cpu; |
| 616 | unsigned int i; |
| 617 | |
| 618 | for_each_possible_cpu(cpu) { |
| 619 | seqcount_t *s = &per_cpu(xt_recseq, cpu); |
| 620 | |
| 621 | i = 0; |
| 622 | xt_entry_foreach(iter, t->entries, t->size) { |
| 623 | struct xt_counters *tmp; |
| 624 | u64 bcnt, pcnt; |
| 625 | unsigned int start; |
| 626 | |
| 627 | tmp = xt_get_per_cpu_counter(&iter->counters, cpu); |
| 628 | do { |
| 629 | start = read_seqcount_begin(s); |
| 630 | bcnt = tmp->bcnt; |
| 631 | pcnt = tmp->pcnt; |
| 632 | } while (read_seqcount_retry(s, start)); |
| 633 | |
| 634 | ADD_COUNTER(counters[i], bcnt, pcnt); |
| 635 | ++i; |
| 636 | cond_resched(); |
| 637 | } |
| 638 | } |
| 639 | } |
| 640 | |
| 641 | static struct xt_counters *alloc_counters(const struct xt_table *table) |
| 642 | { |
| 643 | unsigned int countersize; |
| 644 | struct xt_counters *counters; |
| 645 | const struct xt_table_info *private = table->private; |
| 646 | |
| 647 | /* We need atomic snapshot of counters: rest doesn't change |
| 648 | * (other than comefrom, which userspace doesn't care |
| 649 | * about). |
| 650 | */ |
| 651 | countersize = sizeof(struct xt_counters) * private->number; |
| 652 | counters = vzalloc(countersize); |
| 653 | |
| 654 | if (counters == NULL) |
| 655 | return ERR_PTR(-ENOMEM); |
| 656 | |
| 657 | get_counters(private, counters); |
| 658 | |
| 659 | return counters; |
| 660 | } |
| 661 | |
| 662 | static int copy_entries_to_user(unsigned int total_size, |
| 663 | const struct xt_table *table, |
| 664 | void __user *userptr) |
| 665 | { |
| 666 | unsigned int off, num; |
| 667 | const struct arpt_entry *e; |
| 668 | struct xt_counters *counters; |
| 669 | struct xt_table_info *private = table->private; |
| 670 | int ret = 0; |
| 671 | void *loc_cpu_entry; |
| 672 | |
| 673 | counters = alloc_counters(table); |
| 674 | if (IS_ERR(counters)) |
| 675 | return PTR_ERR(counters); |
| 676 | |
| 677 | loc_cpu_entry = private->entries; |
| 678 | |
| 679 | /* FIXME: use iterator macros --RR */ |
| 680 | /* ... then go back and fix counters and names */ |
| 681 | for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ |
| 682 | const struct xt_entry_target *t; |
| 683 | |
| 684 | e = loc_cpu_entry + off; |
| 685 | if (copy_to_user(userptr + off, e, sizeof(*e))) { |
| 686 | ret = -EFAULT; |
| 687 | goto free_counters; |
| 688 | } |
| 689 | if (copy_to_user(userptr + off |
| 690 | + offsetof(struct arpt_entry, counters), |
| 691 | &counters[num], |
| 692 | sizeof(counters[num])) != 0) { |
| 693 | ret = -EFAULT; |
| 694 | goto free_counters; |
| 695 | } |
| 696 | |
| 697 | t = arpt_get_target_c(e); |
| 698 | if (xt_target_to_user(t, userptr + off + e->target_offset)) { |
| 699 | ret = -EFAULT; |
| 700 | goto free_counters; |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | free_counters: |
| 705 | vfree(counters); |
| 706 | return ret; |
| 707 | } |
| 708 | |
| 709 | #ifdef CONFIG_COMPAT |
| 710 | static void compat_standard_from_user(void *dst, const void *src) |
| 711 | { |
| 712 | int v = *(compat_int_t *)src; |
| 713 | |
| 714 | if (v > 0) |
| 715 | v += xt_compat_calc_jump(NFPROTO_ARP, v); |
| 716 | memcpy(dst, &v, sizeof(v)); |
| 717 | } |
| 718 | |
| 719 | static int compat_standard_to_user(void __user *dst, const void *src) |
| 720 | { |
| 721 | compat_int_t cv = *(int *)src; |
| 722 | |
| 723 | if (cv > 0) |
| 724 | cv -= xt_compat_calc_jump(NFPROTO_ARP, cv); |
| 725 | return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; |
| 726 | } |
| 727 | |
| 728 | static int compat_calc_entry(const struct arpt_entry *e, |
| 729 | const struct xt_table_info *info, |
| 730 | const void *base, struct xt_table_info *newinfo) |
| 731 | { |
| 732 | const struct xt_entry_target *t; |
| 733 | unsigned int entry_offset; |
| 734 | int off, i, ret; |
| 735 | |
| 736 | off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); |
| 737 | entry_offset = (void *)e - base; |
| 738 | |
| 739 | t = arpt_get_target_c(e); |
| 740 | off += xt_compat_target_offset(t->u.kernel.target); |
| 741 | newinfo->size -= off; |
| 742 | ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); |
| 743 | if (ret) |
| 744 | return ret; |
| 745 | |
| 746 | for (i = 0; i < NF_ARP_NUMHOOKS; i++) { |
| 747 | if (info->hook_entry[i] && |
| 748 | (e < (struct arpt_entry *)(base + info->hook_entry[i]))) |
| 749 | newinfo->hook_entry[i] -= off; |
| 750 | if (info->underflow[i] && |
| 751 | (e < (struct arpt_entry *)(base + info->underflow[i]))) |
| 752 | newinfo->underflow[i] -= off; |
| 753 | } |
| 754 | return 0; |
| 755 | } |
| 756 | |
| 757 | static int compat_table_info(const struct xt_table_info *info, |
| 758 | struct xt_table_info *newinfo) |
| 759 | { |
| 760 | struct arpt_entry *iter; |
| 761 | const void *loc_cpu_entry; |
| 762 | int ret; |
| 763 | |
| 764 | if (!newinfo || !info) |
| 765 | return -EINVAL; |
| 766 | |
| 767 | /* we dont care about newinfo->entries */ |
| 768 | memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); |
| 769 | newinfo->initial_entries = 0; |
| 770 | loc_cpu_entry = info->entries; |
| 771 | ret = xt_compat_init_offsets(NFPROTO_ARP, info->number); |
| 772 | if (ret) |
| 773 | return ret; |
| 774 | xt_entry_foreach(iter, loc_cpu_entry, info->size) { |
| 775 | ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); |
| 776 | if (ret != 0) |
| 777 | return ret; |
| 778 | } |
| 779 | return 0; |
| 780 | } |
| 781 | #endif |
| 782 | |
| 783 | static int get_info(struct net *net, void __user *user, |
| 784 | const int *len, int compat) |
| 785 | { |
| 786 | char name[XT_TABLE_MAXNAMELEN]; |
| 787 | struct xt_table *t; |
| 788 | int ret; |
| 789 | |
| 790 | if (*len != sizeof(struct arpt_getinfo)) |
| 791 | return -EINVAL; |
| 792 | |
| 793 | if (copy_from_user(name, user, sizeof(name)) != 0) |
| 794 | return -EFAULT; |
| 795 | |
| 796 | name[XT_TABLE_MAXNAMELEN-1] = '\0'; |
| 797 | #ifdef CONFIG_COMPAT |
| 798 | if (compat) |
| 799 | xt_compat_lock(NFPROTO_ARP); |
| 800 | #endif |
| 801 | t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), |
| 802 | "arptable_%s", name); |
| 803 | if (t) { |
| 804 | struct arpt_getinfo info; |
| 805 | const struct xt_table_info *private = t->private; |
| 806 | #ifdef CONFIG_COMPAT |
| 807 | struct xt_table_info tmp; |
| 808 | |
| 809 | if (compat) { |
| 810 | ret = compat_table_info(private, &tmp); |
| 811 | xt_compat_flush_offsets(NFPROTO_ARP); |
| 812 | private = &tmp; |
| 813 | } |
| 814 | #endif |
| 815 | memset(&info, 0, sizeof(info)); |
| 816 | info.valid_hooks = t->valid_hooks; |
| 817 | memcpy(info.hook_entry, private->hook_entry, |
| 818 | sizeof(info.hook_entry)); |
| 819 | memcpy(info.underflow, private->underflow, |
| 820 | sizeof(info.underflow)); |
| 821 | info.num_entries = private->number; |
| 822 | info.size = private->size; |
| 823 | strcpy(info.name, name); |
| 824 | |
| 825 | if (copy_to_user(user, &info, *len) != 0) |
| 826 | ret = -EFAULT; |
| 827 | else |
| 828 | ret = 0; |
| 829 | xt_table_unlock(t); |
| 830 | module_put(t->me); |
| 831 | } else |
| 832 | ret = -ENOENT; |
| 833 | #ifdef CONFIG_COMPAT |
| 834 | if (compat) |
| 835 | xt_compat_unlock(NFPROTO_ARP); |
| 836 | #endif |
| 837 | return ret; |
| 838 | } |
| 839 | |
| 840 | static int get_entries(struct net *net, struct arpt_get_entries __user *uptr, |
| 841 | const int *len) |
| 842 | { |
| 843 | int ret; |
| 844 | struct arpt_get_entries get; |
| 845 | struct xt_table *t; |
| 846 | |
| 847 | if (*len < sizeof(get)) |
| 848 | return -EINVAL; |
| 849 | if (copy_from_user(&get, uptr, sizeof(get)) != 0) |
| 850 | return -EFAULT; |
| 851 | if (*len != sizeof(struct arpt_get_entries) + get.size) |
| 852 | return -EINVAL; |
| 853 | |
| 854 | get.name[sizeof(get.name) - 1] = '\0'; |
| 855 | |
| 856 | t = xt_find_table_lock(net, NFPROTO_ARP, get.name); |
| 857 | if (t) { |
| 858 | const struct xt_table_info *private = t->private; |
| 859 | |
| 860 | if (get.size == private->size) |
| 861 | ret = copy_entries_to_user(private->size, |
| 862 | t, uptr->entrytable); |
| 863 | else |
| 864 | ret = -EAGAIN; |
| 865 | |
| 866 | module_put(t->me); |
| 867 | xt_table_unlock(t); |
| 868 | } else |
| 869 | ret = -ENOENT; |
| 870 | |
| 871 | return ret; |
| 872 | } |
| 873 | |
| 874 | static int __do_replace(struct net *net, const char *name, |
| 875 | unsigned int valid_hooks, |
| 876 | struct xt_table_info *newinfo, |
| 877 | unsigned int num_counters, |
| 878 | void __user *counters_ptr) |
| 879 | { |
| 880 | int ret; |
| 881 | struct xt_table *t; |
| 882 | struct xt_table_info *oldinfo; |
| 883 | struct xt_counters *counters; |
| 884 | void *loc_cpu_old_entry; |
| 885 | struct arpt_entry *iter; |
| 886 | |
| 887 | ret = 0; |
| 888 | counters = xt_counters_alloc(num_counters); |
| 889 | if (!counters) { |
| 890 | ret = -ENOMEM; |
| 891 | goto out; |
| 892 | } |
| 893 | |
| 894 | t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), |
| 895 | "arptable_%s", name); |
| 896 | if (!t) { |
| 897 | ret = -ENOENT; |
| 898 | goto free_newinfo_counters_untrans; |
| 899 | } |
| 900 | |
| 901 | /* You lied! */ |
| 902 | if (valid_hooks != t->valid_hooks) { |
| 903 | ret = -EINVAL; |
| 904 | goto put_module; |
| 905 | } |
| 906 | |
| 907 | oldinfo = xt_replace_table(t, num_counters, newinfo, &ret); |
| 908 | if (!oldinfo) |
| 909 | goto put_module; |
| 910 | |
| 911 | /* Update module usage count based on number of rules */ |
| 912 | if ((oldinfo->number > oldinfo->initial_entries) || |
| 913 | (newinfo->number <= oldinfo->initial_entries)) |
| 914 | module_put(t->me); |
| 915 | if ((oldinfo->number > oldinfo->initial_entries) && |
| 916 | (newinfo->number <= oldinfo->initial_entries)) |
| 917 | module_put(t->me); |
| 918 | |
| 919 | /* Get the old counters, and synchronize with replace */ |
| 920 | get_counters(oldinfo, counters); |
| 921 | |
| 922 | /* Decrease module usage counts and free resource */ |
| 923 | loc_cpu_old_entry = oldinfo->entries; |
| 924 | xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size) |
| 925 | cleanup_entry(iter); |
| 926 | |
| 927 | xt_free_table_info(oldinfo); |
| 928 | if (copy_to_user(counters_ptr, counters, |
| 929 | sizeof(struct xt_counters) * num_counters) != 0) { |
| 930 | /* Silent error, can't fail, new table is already in place */ |
| 931 | net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n"); |
| 932 | } |
| 933 | vfree(counters); |
| 934 | xt_table_unlock(t); |
| 935 | return ret; |
| 936 | |
| 937 | put_module: |
| 938 | module_put(t->me); |
| 939 | xt_table_unlock(t); |
| 940 | free_newinfo_counters_untrans: |
| 941 | vfree(counters); |
| 942 | out: |
| 943 | return ret; |
| 944 | } |
| 945 | |
| 946 | static int do_replace(struct net *net, const void __user *user, |
| 947 | unsigned int len) |
| 948 | { |
| 949 | int ret; |
| 950 | struct arpt_replace tmp; |
| 951 | struct xt_table_info *newinfo; |
| 952 | void *loc_cpu_entry; |
| 953 | struct arpt_entry *iter; |
| 954 | |
| 955 | if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) |
| 956 | return -EFAULT; |
| 957 | |
| 958 | /* overflow check */ |
| 959 | if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) |
| 960 | return -ENOMEM; |
| 961 | if (tmp.num_counters == 0) |
| 962 | return -EINVAL; |
| 963 | |
| 964 | tmp.name[sizeof(tmp.name)-1] = 0; |
| 965 | |
| 966 | newinfo = xt_alloc_table_info(tmp.size); |
| 967 | if (!newinfo) |
| 968 | return -ENOMEM; |
| 969 | |
| 970 | loc_cpu_entry = newinfo->entries; |
| 971 | if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), |
| 972 | tmp.size) != 0) { |
| 973 | ret = -EFAULT; |
| 974 | goto free_newinfo; |
| 975 | } |
| 976 | |
| 977 | ret = translate_table(newinfo, loc_cpu_entry, &tmp); |
| 978 | if (ret != 0) |
| 979 | goto free_newinfo; |
| 980 | |
| 981 | ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, |
| 982 | tmp.num_counters, tmp.counters); |
| 983 | if (ret) |
| 984 | goto free_newinfo_untrans; |
| 985 | return 0; |
| 986 | |
| 987 | free_newinfo_untrans: |
| 988 | xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) |
| 989 | cleanup_entry(iter); |
| 990 | free_newinfo: |
| 991 | xt_free_table_info(newinfo); |
| 992 | return ret; |
| 993 | } |
| 994 | |
| 995 | static int do_add_counters(struct net *net, const void __user *user, |
| 996 | unsigned int len, int compat) |
| 997 | { |
| 998 | unsigned int i; |
| 999 | struct xt_counters_info tmp; |
| 1000 | struct xt_counters *paddc; |
| 1001 | struct xt_table *t; |
| 1002 | const struct xt_table_info *private; |
| 1003 | int ret = 0; |
| 1004 | struct arpt_entry *iter; |
| 1005 | unsigned int addend; |
| 1006 | |
| 1007 | paddc = xt_copy_counters_from_user(user, len, &tmp, compat); |
| 1008 | if (IS_ERR(paddc)) |
| 1009 | return PTR_ERR(paddc); |
| 1010 | |
| 1011 | t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name); |
| 1012 | if (!t) { |
| 1013 | ret = -ENOENT; |
| 1014 | goto free; |
| 1015 | } |
| 1016 | |
| 1017 | local_bh_disable(); |
| 1018 | private = t->private; |
| 1019 | if (private->number != tmp.num_counters) { |
| 1020 | ret = -EINVAL; |
| 1021 | goto unlock_up_free; |
| 1022 | } |
| 1023 | |
| 1024 | i = 0; |
| 1025 | |
| 1026 | addend = xt_write_recseq_begin(); |
| 1027 | xt_entry_foreach(iter, private->entries, private->size) { |
| 1028 | struct xt_counters *tmp; |
| 1029 | |
| 1030 | tmp = xt_get_this_cpu_counter(&iter->counters); |
| 1031 | ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); |
| 1032 | ++i; |
| 1033 | } |
| 1034 | xt_write_recseq_end(addend); |
| 1035 | unlock_up_free: |
| 1036 | local_bh_enable(); |
| 1037 | xt_table_unlock(t); |
| 1038 | module_put(t->me); |
| 1039 | free: |
| 1040 | vfree(paddc); |
| 1041 | |
| 1042 | return ret; |
| 1043 | } |
| 1044 | |
| 1045 | #ifdef CONFIG_COMPAT |
| 1046 | struct compat_arpt_replace { |
| 1047 | char name[XT_TABLE_MAXNAMELEN]; |
| 1048 | u32 valid_hooks; |
| 1049 | u32 num_entries; |
| 1050 | u32 size; |
| 1051 | u32 hook_entry[NF_ARP_NUMHOOKS]; |
| 1052 | u32 underflow[NF_ARP_NUMHOOKS]; |
| 1053 | u32 num_counters; |
| 1054 | compat_uptr_t counters; |
| 1055 | struct compat_arpt_entry entries[0]; |
| 1056 | }; |
| 1057 | |
| 1058 | static inline void compat_release_entry(struct compat_arpt_entry *e) |
| 1059 | { |
| 1060 | struct xt_entry_target *t; |
| 1061 | |
| 1062 | t = compat_arpt_get_target(e); |
| 1063 | module_put(t->u.kernel.target->me); |
| 1064 | } |
| 1065 | |
| 1066 | static int |
| 1067 | check_compat_entry_size_and_hooks(struct compat_arpt_entry *e, |
| 1068 | struct xt_table_info *newinfo, |
| 1069 | unsigned int *size, |
| 1070 | const unsigned char *base, |
| 1071 | const unsigned char *limit) |
| 1072 | { |
| 1073 | struct xt_entry_target *t; |
| 1074 | struct xt_target *target; |
| 1075 | unsigned int entry_offset; |
| 1076 | int ret, off; |
| 1077 | |
| 1078 | if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 || |
| 1079 | (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit || |
| 1080 | (unsigned char *)e + e->next_offset > limit) |
| 1081 | return -EINVAL; |
| 1082 | |
| 1083 | if (e->next_offset < sizeof(struct compat_arpt_entry) + |
| 1084 | sizeof(struct compat_xt_entry_target)) |
| 1085 | return -EINVAL; |
| 1086 | |
| 1087 | if (!arp_checkentry(&e->arp)) |
| 1088 | return -EINVAL; |
| 1089 | |
| 1090 | ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset, |
| 1091 | e->next_offset); |
| 1092 | if (ret) |
| 1093 | return ret; |
| 1094 | |
| 1095 | off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); |
| 1096 | entry_offset = (void *)e - (void *)base; |
| 1097 | |
| 1098 | t = compat_arpt_get_target(e); |
| 1099 | target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, |
| 1100 | t->u.user.revision); |
| 1101 | if (IS_ERR(target)) { |
| 1102 | ret = PTR_ERR(target); |
| 1103 | goto out; |
| 1104 | } |
| 1105 | t->u.kernel.target = target; |
| 1106 | |
| 1107 | off += xt_compat_target_offset(target); |
| 1108 | *size += off; |
| 1109 | ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); |
| 1110 | if (ret) |
| 1111 | goto release_target; |
| 1112 | |
| 1113 | return 0; |
| 1114 | |
| 1115 | release_target: |
| 1116 | module_put(t->u.kernel.target->me); |
| 1117 | out: |
| 1118 | return ret; |
| 1119 | } |
| 1120 | |
| 1121 | static void |
| 1122 | compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr, |
| 1123 | unsigned int *size, |
| 1124 | struct xt_table_info *newinfo, unsigned char *base) |
| 1125 | { |
| 1126 | struct xt_entry_target *t; |
| 1127 | struct arpt_entry *de; |
| 1128 | unsigned int origsize; |
| 1129 | int h; |
| 1130 | |
| 1131 | origsize = *size; |
| 1132 | de = *dstptr; |
| 1133 | memcpy(de, e, sizeof(struct arpt_entry)); |
| 1134 | memcpy(&de->counters, &e->counters, sizeof(e->counters)); |
| 1135 | |
| 1136 | *dstptr += sizeof(struct arpt_entry); |
| 1137 | *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); |
| 1138 | |
| 1139 | de->target_offset = e->target_offset - (origsize - *size); |
| 1140 | t = compat_arpt_get_target(e); |
| 1141 | xt_compat_target_from_user(t, dstptr, size); |
| 1142 | |
| 1143 | de->next_offset = e->next_offset - (origsize - *size); |
| 1144 | for (h = 0; h < NF_ARP_NUMHOOKS; h++) { |
| 1145 | if ((unsigned char *)de - base < newinfo->hook_entry[h]) |
| 1146 | newinfo->hook_entry[h] -= origsize - *size; |
| 1147 | if ((unsigned char *)de - base < newinfo->underflow[h]) |
| 1148 | newinfo->underflow[h] -= origsize - *size; |
| 1149 | } |
| 1150 | } |
| 1151 | |
| 1152 | static int translate_compat_table(struct xt_table_info **pinfo, |
| 1153 | void **pentry0, |
| 1154 | const struct compat_arpt_replace *compatr) |
| 1155 | { |
| 1156 | unsigned int i, j; |
| 1157 | struct xt_table_info *newinfo, *info; |
| 1158 | void *pos, *entry0, *entry1; |
| 1159 | struct compat_arpt_entry *iter0; |
| 1160 | struct arpt_replace repl; |
| 1161 | unsigned int size; |
| 1162 | int ret; |
| 1163 | |
| 1164 | info = *pinfo; |
| 1165 | entry0 = *pentry0; |
| 1166 | size = compatr->size; |
| 1167 | info->number = compatr->num_entries; |
| 1168 | |
| 1169 | j = 0; |
| 1170 | xt_compat_lock(NFPROTO_ARP); |
| 1171 | ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries); |
| 1172 | if (ret) |
| 1173 | goto out_unlock; |
| 1174 | /* Walk through entries, checking offsets. */ |
| 1175 | xt_entry_foreach(iter0, entry0, compatr->size) { |
| 1176 | ret = check_compat_entry_size_and_hooks(iter0, info, &size, |
| 1177 | entry0, |
| 1178 | entry0 + compatr->size); |
| 1179 | if (ret != 0) |
| 1180 | goto out_unlock; |
| 1181 | ++j; |
| 1182 | } |
| 1183 | |
| 1184 | ret = -EINVAL; |
| 1185 | if (j != compatr->num_entries) |
| 1186 | goto out_unlock; |
| 1187 | |
| 1188 | ret = -ENOMEM; |
| 1189 | newinfo = xt_alloc_table_info(size); |
| 1190 | if (!newinfo) |
| 1191 | goto out_unlock; |
| 1192 | |
| 1193 | newinfo->number = compatr->num_entries; |
| 1194 | for (i = 0; i < NF_ARP_NUMHOOKS; i++) { |
| 1195 | newinfo->hook_entry[i] = compatr->hook_entry[i]; |
| 1196 | newinfo->underflow[i] = compatr->underflow[i]; |
| 1197 | } |
| 1198 | entry1 = newinfo->entries; |
| 1199 | pos = entry1; |
| 1200 | size = compatr->size; |
| 1201 | xt_entry_foreach(iter0, entry0, compatr->size) |
| 1202 | compat_copy_entry_from_user(iter0, &pos, &size, |
| 1203 | newinfo, entry1); |
| 1204 | |
| 1205 | /* all module references in entry0 are now gone */ |
| 1206 | |
| 1207 | xt_compat_flush_offsets(NFPROTO_ARP); |
| 1208 | xt_compat_unlock(NFPROTO_ARP); |
| 1209 | |
| 1210 | memcpy(&repl, compatr, sizeof(*compatr)); |
| 1211 | |
| 1212 | for (i = 0; i < NF_ARP_NUMHOOKS; i++) { |
| 1213 | repl.hook_entry[i] = newinfo->hook_entry[i]; |
| 1214 | repl.underflow[i] = newinfo->underflow[i]; |
| 1215 | } |
| 1216 | |
| 1217 | repl.num_counters = 0; |
| 1218 | repl.counters = NULL; |
| 1219 | repl.size = newinfo->size; |
| 1220 | ret = translate_table(newinfo, entry1, &repl); |
| 1221 | if (ret) |
| 1222 | goto free_newinfo; |
| 1223 | |
| 1224 | *pinfo = newinfo; |
| 1225 | *pentry0 = entry1; |
| 1226 | xt_free_table_info(info); |
| 1227 | return 0; |
| 1228 | |
| 1229 | free_newinfo: |
| 1230 | xt_free_table_info(newinfo); |
| 1231 | return ret; |
| 1232 | out_unlock: |
| 1233 | xt_compat_flush_offsets(NFPROTO_ARP); |
| 1234 | xt_compat_unlock(NFPROTO_ARP); |
| 1235 | xt_entry_foreach(iter0, entry0, compatr->size) { |
| 1236 | if (j-- == 0) |
| 1237 | break; |
| 1238 | compat_release_entry(iter0); |
| 1239 | } |
| 1240 | return ret; |
| 1241 | } |
| 1242 | |
| 1243 | static int compat_do_replace(struct net *net, void __user *user, |
| 1244 | unsigned int len) |
| 1245 | { |
| 1246 | int ret; |
| 1247 | struct compat_arpt_replace tmp; |
| 1248 | struct xt_table_info *newinfo; |
| 1249 | void *loc_cpu_entry; |
| 1250 | struct arpt_entry *iter; |
| 1251 | |
| 1252 | if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) |
| 1253 | return -EFAULT; |
| 1254 | |
| 1255 | /* overflow check */ |
| 1256 | if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) |
| 1257 | return -ENOMEM; |
| 1258 | if (tmp.num_counters == 0) |
| 1259 | return -EINVAL; |
| 1260 | |
| 1261 | tmp.name[sizeof(tmp.name)-1] = 0; |
| 1262 | |
| 1263 | newinfo = xt_alloc_table_info(tmp.size); |
| 1264 | if (!newinfo) |
| 1265 | return -ENOMEM; |
| 1266 | |
| 1267 | loc_cpu_entry = newinfo->entries; |
| 1268 | if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) { |
| 1269 | ret = -EFAULT; |
| 1270 | goto free_newinfo; |
| 1271 | } |
| 1272 | |
| 1273 | ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp); |
| 1274 | if (ret != 0) |
| 1275 | goto free_newinfo; |
| 1276 | |
| 1277 | ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, |
| 1278 | tmp.num_counters, compat_ptr(tmp.counters)); |
| 1279 | if (ret) |
| 1280 | goto free_newinfo_untrans; |
| 1281 | return 0; |
| 1282 | |
| 1283 | free_newinfo_untrans: |
| 1284 | xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) |
| 1285 | cleanup_entry(iter); |
| 1286 | free_newinfo: |
| 1287 | xt_free_table_info(newinfo); |
| 1288 | return ret; |
| 1289 | } |
| 1290 | |
| 1291 | static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, |
| 1292 | unsigned int len) |
| 1293 | { |
| 1294 | int ret; |
| 1295 | |
| 1296 | if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
| 1297 | return -EPERM; |
| 1298 | |
| 1299 | switch (cmd) { |
| 1300 | case ARPT_SO_SET_REPLACE: |
| 1301 | ret = compat_do_replace(sock_net(sk), user, len); |
| 1302 | break; |
| 1303 | |
| 1304 | case ARPT_SO_SET_ADD_COUNTERS: |
| 1305 | ret = do_add_counters(sock_net(sk), user, len, 1); |
| 1306 | break; |
| 1307 | |
| 1308 | default: |
| 1309 | ret = -EINVAL; |
| 1310 | } |
| 1311 | |
| 1312 | return ret; |
| 1313 | } |
| 1314 | |
| 1315 | static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr, |
| 1316 | compat_uint_t *size, |
| 1317 | struct xt_counters *counters, |
| 1318 | unsigned int i) |
| 1319 | { |
| 1320 | struct xt_entry_target *t; |
| 1321 | struct compat_arpt_entry __user *ce; |
| 1322 | u_int16_t target_offset, next_offset; |
| 1323 | compat_uint_t origsize; |
| 1324 | int ret; |
| 1325 | |
| 1326 | origsize = *size; |
| 1327 | ce = *dstptr; |
| 1328 | if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 || |
| 1329 | copy_to_user(&ce->counters, &counters[i], |
| 1330 | sizeof(counters[i])) != 0) |
| 1331 | return -EFAULT; |
| 1332 | |
| 1333 | *dstptr += sizeof(struct compat_arpt_entry); |
| 1334 | *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); |
| 1335 | |
| 1336 | target_offset = e->target_offset - (origsize - *size); |
| 1337 | |
| 1338 | t = arpt_get_target(e); |
| 1339 | ret = xt_compat_target_to_user(t, dstptr, size); |
| 1340 | if (ret) |
| 1341 | return ret; |
| 1342 | next_offset = e->next_offset - (origsize - *size); |
| 1343 | if (put_user(target_offset, &ce->target_offset) != 0 || |
| 1344 | put_user(next_offset, &ce->next_offset) != 0) |
| 1345 | return -EFAULT; |
| 1346 | return 0; |
| 1347 | } |
| 1348 | |
| 1349 | static int compat_copy_entries_to_user(unsigned int total_size, |
| 1350 | struct xt_table *table, |
| 1351 | void __user *userptr) |
| 1352 | { |
| 1353 | struct xt_counters *counters; |
| 1354 | const struct xt_table_info *private = table->private; |
| 1355 | void __user *pos; |
| 1356 | unsigned int size; |
| 1357 | int ret = 0; |
| 1358 | unsigned int i = 0; |
| 1359 | struct arpt_entry *iter; |
| 1360 | |
| 1361 | counters = alloc_counters(table); |
| 1362 | if (IS_ERR(counters)) |
| 1363 | return PTR_ERR(counters); |
| 1364 | |
| 1365 | pos = userptr; |
| 1366 | size = total_size; |
| 1367 | xt_entry_foreach(iter, private->entries, total_size) { |
| 1368 | ret = compat_copy_entry_to_user(iter, &pos, |
| 1369 | &size, counters, i++); |
| 1370 | if (ret != 0) |
| 1371 | break; |
| 1372 | } |
| 1373 | vfree(counters); |
| 1374 | return ret; |
| 1375 | } |
| 1376 | |
| 1377 | struct compat_arpt_get_entries { |
| 1378 | char name[XT_TABLE_MAXNAMELEN]; |
| 1379 | compat_uint_t size; |
| 1380 | struct compat_arpt_entry entrytable[0]; |
| 1381 | }; |
| 1382 | |
| 1383 | static int compat_get_entries(struct net *net, |
| 1384 | struct compat_arpt_get_entries __user *uptr, |
| 1385 | int *len) |
| 1386 | { |
| 1387 | int ret; |
| 1388 | struct compat_arpt_get_entries get; |
| 1389 | struct xt_table *t; |
| 1390 | |
| 1391 | if (*len < sizeof(get)) |
| 1392 | return -EINVAL; |
| 1393 | if (copy_from_user(&get, uptr, sizeof(get)) != 0) |
| 1394 | return -EFAULT; |
| 1395 | if (*len != sizeof(struct compat_arpt_get_entries) + get.size) |
| 1396 | return -EINVAL; |
| 1397 | |
| 1398 | get.name[sizeof(get.name) - 1] = '\0'; |
| 1399 | |
| 1400 | xt_compat_lock(NFPROTO_ARP); |
| 1401 | t = xt_find_table_lock(net, NFPROTO_ARP, get.name); |
| 1402 | if (t) { |
| 1403 | const struct xt_table_info *private = t->private; |
| 1404 | struct xt_table_info info; |
| 1405 | |
| 1406 | ret = compat_table_info(private, &info); |
| 1407 | if (!ret && get.size == info.size) { |
| 1408 | ret = compat_copy_entries_to_user(private->size, |
| 1409 | t, uptr->entrytable); |
| 1410 | } else if (!ret) |
| 1411 | ret = -EAGAIN; |
| 1412 | |
| 1413 | xt_compat_flush_offsets(NFPROTO_ARP); |
| 1414 | module_put(t->me); |
| 1415 | xt_table_unlock(t); |
| 1416 | } else |
| 1417 | ret = -ENOENT; |
| 1418 | |
| 1419 | xt_compat_unlock(NFPROTO_ARP); |
| 1420 | return ret; |
| 1421 | } |
| 1422 | |
| 1423 | static int do_arpt_get_ctl(struct sock *, int, void __user *, int *); |
| 1424 | |
| 1425 | static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, |
| 1426 | int *len) |
| 1427 | { |
| 1428 | int ret; |
| 1429 | |
| 1430 | if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
| 1431 | return -EPERM; |
| 1432 | |
| 1433 | switch (cmd) { |
| 1434 | case ARPT_SO_GET_INFO: |
| 1435 | ret = get_info(sock_net(sk), user, len, 1); |
| 1436 | break; |
| 1437 | case ARPT_SO_GET_ENTRIES: |
| 1438 | ret = compat_get_entries(sock_net(sk), user, len); |
| 1439 | break; |
| 1440 | default: |
| 1441 | ret = do_arpt_get_ctl(sk, cmd, user, len); |
| 1442 | } |
| 1443 | return ret; |
| 1444 | } |
| 1445 | #endif |
| 1446 | |
| 1447 | static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) |
| 1448 | { |
| 1449 | int ret; |
| 1450 | |
| 1451 | if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
| 1452 | return -EPERM; |
| 1453 | |
| 1454 | switch (cmd) { |
| 1455 | case ARPT_SO_SET_REPLACE: |
| 1456 | ret = do_replace(sock_net(sk), user, len); |
| 1457 | break; |
| 1458 | |
| 1459 | case ARPT_SO_SET_ADD_COUNTERS: |
| 1460 | ret = do_add_counters(sock_net(sk), user, len, 0); |
| 1461 | break; |
| 1462 | |
| 1463 | default: |
| 1464 | ret = -EINVAL; |
| 1465 | } |
| 1466 | |
| 1467 | return ret; |
| 1468 | } |
| 1469 | |
| 1470 | static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) |
| 1471 | { |
| 1472 | int ret; |
| 1473 | |
| 1474 | if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
| 1475 | return -EPERM; |
| 1476 | |
| 1477 | switch (cmd) { |
| 1478 | case ARPT_SO_GET_INFO: |
| 1479 | ret = get_info(sock_net(sk), user, len, 0); |
| 1480 | break; |
| 1481 | |
| 1482 | case ARPT_SO_GET_ENTRIES: |
| 1483 | ret = get_entries(sock_net(sk), user, len); |
| 1484 | break; |
| 1485 | |
| 1486 | case ARPT_SO_GET_REVISION_TARGET: { |
| 1487 | struct xt_get_revision rev; |
| 1488 | |
| 1489 | if (*len != sizeof(rev)) { |
| 1490 | ret = -EINVAL; |
| 1491 | break; |
| 1492 | } |
| 1493 | if (copy_from_user(&rev, user, sizeof(rev)) != 0) { |
| 1494 | ret = -EFAULT; |
| 1495 | break; |
| 1496 | } |
| 1497 | rev.name[sizeof(rev.name)-1] = 0; |
| 1498 | |
| 1499 | try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name, |
| 1500 | rev.revision, 1, &ret), |
| 1501 | "arpt_%s", rev.name); |
| 1502 | break; |
| 1503 | } |
| 1504 | |
| 1505 | default: |
| 1506 | ret = -EINVAL; |
| 1507 | } |
| 1508 | |
| 1509 | return ret; |
| 1510 | } |
| 1511 | |
| 1512 | static void __arpt_unregister_table(struct xt_table *table) |
| 1513 | { |
| 1514 | struct xt_table_info *private; |
| 1515 | void *loc_cpu_entry; |
| 1516 | struct module *table_owner = table->me; |
| 1517 | struct arpt_entry *iter; |
| 1518 | |
| 1519 | private = xt_unregister_table(table); |
| 1520 | |
| 1521 | /* Decrease module usage counts and free resources */ |
| 1522 | loc_cpu_entry = private->entries; |
| 1523 | xt_entry_foreach(iter, loc_cpu_entry, private->size) |
| 1524 | cleanup_entry(iter); |
| 1525 | if (private->number > private->initial_entries) |
| 1526 | module_put(table_owner); |
| 1527 | xt_free_table_info(private); |
| 1528 | } |
| 1529 | |
| 1530 | int arpt_register_table(struct net *net, |
| 1531 | const struct xt_table *table, |
| 1532 | const struct arpt_replace *repl, |
| 1533 | const struct nf_hook_ops *ops, |
| 1534 | struct xt_table **res) |
| 1535 | { |
| 1536 | int ret; |
| 1537 | struct xt_table_info *newinfo; |
| 1538 | struct xt_table_info bootstrap = {0}; |
| 1539 | void *loc_cpu_entry; |
| 1540 | struct xt_table *new_table; |
| 1541 | |
| 1542 | newinfo = xt_alloc_table_info(repl->size); |
| 1543 | if (!newinfo) |
| 1544 | return -ENOMEM; |
| 1545 | |
| 1546 | loc_cpu_entry = newinfo->entries; |
| 1547 | memcpy(loc_cpu_entry, repl->entries, repl->size); |
| 1548 | |
| 1549 | ret = translate_table(newinfo, loc_cpu_entry, repl); |
| 1550 | if (ret != 0) |
| 1551 | goto out_free; |
| 1552 | |
| 1553 | new_table = xt_register_table(net, table, &bootstrap, newinfo); |
| 1554 | if (IS_ERR(new_table)) { |
| 1555 | ret = PTR_ERR(new_table); |
| 1556 | goto out_free; |
| 1557 | } |
| 1558 | |
| 1559 | /* set res now, will see skbs right after nf_register_net_hooks */ |
| 1560 | WRITE_ONCE(*res, new_table); |
| 1561 | |
| 1562 | ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); |
| 1563 | if (ret != 0) { |
| 1564 | __arpt_unregister_table(new_table); |
| 1565 | *res = NULL; |
| 1566 | } |
| 1567 | |
| 1568 | return ret; |
| 1569 | |
| 1570 | out_free: |
| 1571 | xt_free_table_info(newinfo); |
| 1572 | return ret; |
| 1573 | } |
| 1574 | |
| 1575 | void arpt_unregister_table(struct net *net, struct xt_table *table, |
| 1576 | const struct nf_hook_ops *ops) |
| 1577 | { |
| 1578 | nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); |
| 1579 | __arpt_unregister_table(table); |
| 1580 | } |
| 1581 | |
| 1582 | /* The built-in targets: standard (NULL) and error. */ |
| 1583 | static struct xt_target arpt_builtin_tg[] __read_mostly = { |
| 1584 | { |
| 1585 | .name = XT_STANDARD_TARGET, |
| 1586 | .targetsize = sizeof(int), |
| 1587 | .family = NFPROTO_ARP, |
| 1588 | #ifdef CONFIG_COMPAT |
| 1589 | .compatsize = sizeof(compat_int_t), |
| 1590 | .compat_from_user = compat_standard_from_user, |
| 1591 | .compat_to_user = compat_standard_to_user, |
| 1592 | #endif |
| 1593 | }, |
| 1594 | { |
| 1595 | .name = XT_ERROR_TARGET, |
| 1596 | .target = arpt_error, |
| 1597 | .targetsize = XT_FUNCTION_MAXNAMELEN, |
| 1598 | .family = NFPROTO_ARP, |
| 1599 | }, |
| 1600 | }; |
| 1601 | |
| 1602 | static struct nf_sockopt_ops arpt_sockopts = { |
| 1603 | .pf = PF_INET, |
| 1604 | .set_optmin = ARPT_BASE_CTL, |
| 1605 | .set_optmax = ARPT_SO_SET_MAX+1, |
| 1606 | .set = do_arpt_set_ctl, |
| 1607 | #ifdef CONFIG_COMPAT |
| 1608 | .compat_set = compat_do_arpt_set_ctl, |
| 1609 | #endif |
| 1610 | .get_optmin = ARPT_BASE_CTL, |
| 1611 | .get_optmax = ARPT_SO_GET_MAX+1, |
| 1612 | .get = do_arpt_get_ctl, |
| 1613 | #ifdef CONFIG_COMPAT |
| 1614 | .compat_get = compat_do_arpt_get_ctl, |
| 1615 | #endif |
| 1616 | .owner = THIS_MODULE, |
| 1617 | }; |
| 1618 | |
| 1619 | static int __net_init arp_tables_net_init(struct net *net) |
| 1620 | { |
| 1621 | return xt_proto_init(net, NFPROTO_ARP); |
| 1622 | } |
| 1623 | |
| 1624 | static void __net_exit arp_tables_net_exit(struct net *net) |
| 1625 | { |
| 1626 | xt_proto_fini(net, NFPROTO_ARP); |
| 1627 | } |
| 1628 | |
| 1629 | static struct pernet_operations arp_tables_net_ops = { |
| 1630 | .init = arp_tables_net_init, |
| 1631 | .exit = arp_tables_net_exit, |
| 1632 | }; |
| 1633 | |
| 1634 | static int __init arp_tables_init(void) |
| 1635 | { |
| 1636 | int ret; |
| 1637 | |
| 1638 | ret = register_pernet_subsys(&arp_tables_net_ops); |
| 1639 | if (ret < 0) |
| 1640 | goto err1; |
| 1641 | |
| 1642 | /* No one else will be downing sem now, so we won't sleep */ |
| 1643 | ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); |
| 1644 | if (ret < 0) |
| 1645 | goto err2; |
| 1646 | |
| 1647 | /* Register setsockopt */ |
| 1648 | ret = nf_register_sockopt(&arpt_sockopts); |
| 1649 | if (ret < 0) |
| 1650 | goto err4; |
| 1651 | |
| 1652 | pr_info("arp_tables: (C) 2002 David S. Miller\n"); |
| 1653 | return 0; |
| 1654 | |
| 1655 | err4: |
| 1656 | xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); |
| 1657 | err2: |
| 1658 | unregister_pernet_subsys(&arp_tables_net_ops); |
| 1659 | err1: |
| 1660 | return ret; |
| 1661 | } |
| 1662 | |
| 1663 | static void __exit arp_tables_fini(void) |
| 1664 | { |
| 1665 | nf_unregister_sockopt(&arpt_sockopts); |
| 1666 | xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); |
| 1667 | unregister_pernet_subsys(&arp_tables_net_ops); |
| 1668 | } |
| 1669 | |
| 1670 | EXPORT_SYMBOL(arpt_register_table); |
| 1671 | EXPORT_SYMBOL(arpt_unregister_table); |
| 1672 | EXPORT_SYMBOL(arpt_do_table); |
| 1673 | |
| 1674 | module_init(arp_tables_init); |
| 1675 | module_exit(arp_tables_fini); |