1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * NETLINK Netlink attributes 4 * 5 * Authors: Thomas Graf <tgraf@suug.ch> 6 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 7 */ 8 9 #include <linux/export.h> 10 #include <linux/kernel.h> 11 #include <linux/errno.h> 12 #include <linux/jiffies.h> 13 #include <linux/skbuff.h> 14 #include <linux/string.h> 15 #include <linux/types.h> 16 #include <net/netlink.h> 17 18 /* For these data types, attribute length should be exactly the given 19 * size. However, to maintain compatibility with broken commands, if the 20 * attribute length does not match the expected size a warning is emitted 21 * to the user that the command is sending invalid data and needs to be fixed. 22 */ 23 static const u8 nla_attr_len[NLA_TYPE_MAX+1] = { 24 [NLA_U8] = sizeof(u8), 25 [NLA_U16] = sizeof(u16), 26 [NLA_U32] = sizeof(u32), 27 [NLA_U64] = sizeof(u64), 28 [NLA_S8] = sizeof(s8), 29 [NLA_S16] = sizeof(s16), 30 [NLA_S32] = sizeof(s32), 31 [NLA_S64] = sizeof(s64), 32 }; 33 34 static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { 35 [NLA_U8] = sizeof(u8), 36 [NLA_U16] = sizeof(u16), 37 [NLA_U32] = sizeof(u32), 38 [NLA_U64] = sizeof(u64), 39 [NLA_MSECS] = sizeof(u64), 40 [NLA_NESTED] = NLA_HDRLEN, 41 [NLA_S8] = sizeof(s8), 42 [NLA_S16] = sizeof(s16), 43 [NLA_S32] = sizeof(s32), 44 [NLA_S64] = sizeof(s64), 45 }; 46 47 /* 48 * Nested policies might refer back to the original 49 * policy in some cases, and userspace could try to 50 * abuse that and recurse by nesting in the right 51 * ways. Limit recursion to avoid this problem. 52 */ 53 #define MAX_POLICY_RECURSION_DEPTH 10 54 55 static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, 56 const struct nla_policy *policy, 57 unsigned int validate, 58 struct netlink_ext_ack *extack, 59 struct nlattr **tb, unsigned int depth); 60 61 static int validate_nla_bitfield32(const struct nlattr *nla, 62 const u32 valid_flags_mask) 63 { 64 const struct nla_bitfield32 *bf = nla_data(nla); 65 66 if (!valid_flags_mask) 67 return -EINVAL; 68 69 /*disallow invalid bit selector */ 70 if (bf->selector & ~valid_flags_mask) 71 return -EINVAL; 72 73 /*disallow invalid bit values */ 74 if (bf->value & ~valid_flags_mask) 75 return -EINVAL; 76 77 /*disallow valid bit values that are not selected*/ 78 if (bf->value & ~bf->selector) 79 return -EINVAL; 80 81 return 0; 82 } 83 84 static int nla_validate_array(const struct nlattr *head, int len, int maxtype, 85 const struct nla_policy *policy, 86 struct netlink_ext_ack *extack, 87 unsigned int validate, unsigned int depth) 88 { 89 const struct nlattr *entry; 90 int rem; 91 92 nla_for_each_attr(entry, head, len, rem) { 93 int ret; 94 95 if (nla_len(entry) == 0) 96 continue; 97 98 if (nla_len(entry) < NLA_HDRLEN) { 99 NL_SET_ERR_MSG_ATTR_POL(extack, entry, policy, 100 "Array element too short"); 101 return -ERANGE; 102 } 103 104 ret = __nla_validate_parse(nla_data(entry), nla_len(entry), 105 maxtype, policy, validate, extack, 106 NULL, depth + 1); 107 if (ret < 0) 108 return ret; 109 } 110 111 return 0; 112 } 113 114 void nla_get_range_unsigned(const struct nla_policy *pt, 115 struct netlink_range_validation *range) 116 { 117 WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR && 118 (pt->min < 0 || pt->max < 0)); 119 120 range->min = 0; 121 122 switch (pt->type) { 123 case NLA_U8: 124 range->max = U8_MAX; 125 break; 126 case NLA_U16: 127 case NLA_BINARY: 128 range->max = U16_MAX; 129 break; 130 case NLA_U32: 131 range->max = U32_MAX; 132 break; 133 case NLA_U64: 134 case NLA_MSECS: 135 range->max = U64_MAX; 136 break; 137 default: 138 WARN_ON_ONCE(1); 139 return; 140 } 141 142 switch (pt->validation_type) { 143 case NLA_VALIDATE_RANGE: 144 case NLA_VALIDATE_RANGE_WARN_TOO_LONG: 145 range->min = pt->min; 146 range->max = pt->max; 147 break; 148 case NLA_VALIDATE_RANGE_PTR: 149 *range = *pt->range; 150 break; 151 case NLA_VALIDATE_MIN: 152 range->min = pt->min; 153 break; 154 case NLA_VALIDATE_MAX: 155 range->max = pt->max; 156 break; 157 default: 158 break; 159 } 160 } 161 162 static int nla_validate_range_unsigned(const struct nla_policy *pt, 163 const struct nlattr *nla, 164 struct netlink_ext_ack *extack, 165 unsigned int validate) 166 { 167 struct netlink_range_validation range; 168 u64 value; 169 170 switch (pt->type) { 171 case NLA_U8: 172 value = nla_get_u8(nla); 173 break; 174 case NLA_U16: 175 value = nla_get_u16(nla); 176 break; 177 case NLA_U32: 178 value = nla_get_u32(nla); 179 break; 180 case NLA_U64: 181 case NLA_MSECS: 182 value = nla_get_u64(nla); 183 break; 184 case NLA_BINARY: 185 value = nla_len(nla); 186 break; 187 default: 188 return -EINVAL; 189 } 190 191 nla_get_range_unsigned(pt, &range); 192 193 if (pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG && 194 pt->type == NLA_BINARY && value > range.max) { 195 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", 196 current->comm, pt->type); 197 if (validate & NL_VALIDATE_STRICT_ATTRS) { 198 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 199 "invalid attribute length"); 200 return -EINVAL; 201 } 202 203 /* this assumes min <= max (don't validate against min) */ 204 return 0; 205 } 206 207 if (value < range.min || value > range.max) { 208 bool binary = pt->type == NLA_BINARY; 209 210 if (binary) 211 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 212 "binary attribute size out of range"); 213 else 214 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 215 "integer out of range"); 216 217 return -ERANGE; 218 } 219 220 return 0; 221 } 222 223 void nla_get_range_signed(const struct nla_policy *pt, 224 struct netlink_range_validation_signed *range) 225 { 226 switch (pt->type) { 227 case NLA_S8: 228 range->min = S8_MIN; 229 range->max = S8_MAX; 230 break; 231 case NLA_S16: 232 range->min = S16_MIN; 233 range->max = S16_MAX; 234 break; 235 case NLA_S32: 236 range->min = S32_MIN; 237 range->max = S32_MAX; 238 break; 239 case NLA_S64: 240 range->min = S64_MIN; 241 range->max = S64_MAX; 242 break; 243 default: 244 WARN_ON_ONCE(1); 245 return; 246 } 247 248 switch (pt->validation_type) { 249 case NLA_VALIDATE_RANGE: 250 range->min = pt->min; 251 range->max = pt->max; 252 break; 253 case NLA_VALIDATE_RANGE_PTR: 254 *range = *pt->range_signed; 255 break; 256 case NLA_VALIDATE_MIN: 257 range->min = pt->min; 258 break; 259 case NLA_VALIDATE_MAX: 260 range->max = pt->max; 261 break; 262 default: 263 break; 264 } 265 } 266 267 static int nla_validate_int_range_signed(const struct nla_policy *pt, 268 const struct nlattr *nla, 269 struct netlink_ext_ack *extack) 270 { 271 struct netlink_range_validation_signed range; 272 s64 value; 273 274 switch (pt->type) { 275 case NLA_S8: 276 value = nla_get_s8(nla); 277 break; 278 case NLA_S16: 279 value = nla_get_s16(nla); 280 break; 281 case NLA_S32: 282 value = nla_get_s32(nla); 283 break; 284 case NLA_S64: 285 value = nla_get_s64(nla); 286 break; 287 default: 288 return -EINVAL; 289 } 290 291 nla_get_range_signed(pt, &range); 292 293 if (value < range.min || value > range.max) { 294 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 295 "integer out of range"); 296 return -ERANGE; 297 } 298 299 return 0; 300 } 301 302 static int nla_validate_int_range(const struct nla_policy *pt, 303 const struct nlattr *nla, 304 struct netlink_ext_ack *extack, 305 unsigned int validate) 306 { 307 switch (pt->type) { 308 case NLA_U8: 309 case NLA_U16: 310 case NLA_U32: 311 case NLA_U64: 312 case NLA_MSECS: 313 case NLA_BINARY: 314 return nla_validate_range_unsigned(pt, nla, extack, validate); 315 case NLA_S8: 316 case NLA_S16: 317 case NLA_S32: 318 case NLA_S64: 319 return nla_validate_int_range_signed(pt, nla, extack); 320 default: 321 WARN_ON(1); 322 return -EINVAL; 323 } 324 } 325 326 static int nla_validate_mask(const struct nla_policy *pt, 327 const struct nlattr *nla, 328 struct netlink_ext_ack *extack) 329 { 330 u64 value; 331 332 switch (pt->type) { 333 case NLA_U8: 334 value = nla_get_u8(nla); 335 break; 336 case NLA_U16: 337 value = nla_get_u16(nla); 338 break; 339 case NLA_U32: 340 value = nla_get_u32(nla); 341 break; 342 case NLA_U64: 343 value = nla_get_u64(nla); 344 break; 345 default: 346 return -EINVAL; 347 } 348 349 if (value & ~(u64)pt->mask) { 350 NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set"); 351 return -EINVAL; 352 } 353 354 return 0; 355 } 356 357 static int validate_nla(const struct nlattr *nla, int maxtype, 358 const struct nla_policy *policy, unsigned int validate, 359 struct netlink_ext_ack *extack, unsigned int depth) 360 { 361 u16 strict_start_type = policy[0].strict_start_type; 362 const struct nla_policy *pt; 363 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); 364 int err = -ERANGE; 365 366 if (strict_start_type && type >= strict_start_type) 367 validate |= NL_VALIDATE_STRICT; 368 369 if (type <= 0 || type > maxtype) 370 return 0; 371 372 pt = &policy[type]; 373 374 BUG_ON(pt->type > NLA_TYPE_MAX); 375 376 if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) { 377 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", 378 current->comm, type); 379 if (validate & NL_VALIDATE_STRICT_ATTRS) { 380 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 381 "invalid attribute length"); 382 return -EINVAL; 383 } 384 } 385 386 if (validate & NL_VALIDATE_NESTED) { 387 if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) && 388 !(nla->nla_type & NLA_F_NESTED)) { 389 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 390 "NLA_F_NESTED is missing"); 391 return -EINVAL; 392 } 393 if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY && 394 pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) { 395 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 396 "NLA_F_NESTED not expected"); 397 return -EINVAL; 398 } 399 } 400 401 switch (pt->type) { 402 case NLA_REJECT: 403 if (extack && pt->reject_message) { 404 NL_SET_BAD_ATTR(extack, nla); 405 extack->_msg = pt->reject_message; 406 return -EINVAL; 407 } 408 err = -EINVAL; 409 goto out_err; 410 411 case NLA_FLAG: 412 if (attrlen > 0) 413 goto out_err; 414 break; 415 416 case NLA_BITFIELD32: 417 if (attrlen != sizeof(struct nla_bitfield32)) 418 goto out_err; 419 420 err = validate_nla_bitfield32(nla, pt->bitfield32_valid); 421 if (err) 422 goto out_err; 423 break; 424 425 case NLA_NUL_STRING: 426 if (pt->len) 427 minlen = min_t(int, attrlen, pt->len + 1); 428 else 429 minlen = attrlen; 430 431 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) { 432 err = -EINVAL; 433 goto out_err; 434 } 435 fallthrough; 436 437 case NLA_STRING: 438 if (attrlen < 1) 439 goto out_err; 440 441 if (pt->len) { 442 char *buf = nla_data(nla); 443 444 if (buf[attrlen - 1] == '\0') 445 attrlen--; 446 447 if (attrlen > pt->len) 448 goto out_err; 449 } 450 break; 451 452 case NLA_BINARY: 453 if (pt->len && attrlen > pt->len) 454 goto out_err; 455 break; 456 457 case NLA_NESTED: 458 /* a nested attributes is allowed to be empty; if its not, 459 * it must have a size of at least NLA_HDRLEN. 460 */ 461 if (attrlen == 0) 462 break; 463 if (attrlen < NLA_HDRLEN) 464 goto out_err; 465 if (pt->nested_policy) { 466 err = __nla_validate_parse(nla_data(nla), nla_len(nla), 467 pt->len, pt->nested_policy, 468 validate, extack, NULL, 469 depth + 1); 470 if (err < 0) { 471 /* 472 * return directly to preserve the inner 473 * error message/attribute pointer 474 */ 475 return err; 476 } 477 } 478 break; 479 case NLA_NESTED_ARRAY: 480 /* a nested array attribute is allowed to be empty; if its not, 481 * it must have a size of at least NLA_HDRLEN. 482 */ 483 if (attrlen == 0) 484 break; 485 if (attrlen < NLA_HDRLEN) 486 goto out_err; 487 if (pt->nested_policy) { 488 int err; 489 490 err = nla_validate_array(nla_data(nla), nla_len(nla), 491 pt->len, pt->nested_policy, 492 extack, validate, depth); 493 if (err < 0) { 494 /* 495 * return directly to preserve the inner 496 * error message/attribute pointer 497 */ 498 return err; 499 } 500 } 501 break; 502 503 case NLA_UNSPEC: 504 if (validate & NL_VALIDATE_UNSPEC) { 505 NL_SET_ERR_MSG_ATTR(extack, nla, 506 "Unsupported attribute"); 507 return -EINVAL; 508 } 509 if (attrlen < pt->len) 510 goto out_err; 511 break; 512 513 default: 514 if (pt->len) 515 minlen = pt->len; 516 else 517 minlen = nla_attr_minlen[pt->type]; 518 519 if (attrlen < minlen) 520 goto out_err; 521 } 522 523 /* further validation */ 524 switch (pt->validation_type) { 525 case NLA_VALIDATE_NONE: 526 /* nothing to do */ 527 break; 528 case NLA_VALIDATE_RANGE_PTR: 529 case NLA_VALIDATE_RANGE: 530 case NLA_VALIDATE_RANGE_WARN_TOO_LONG: 531 case NLA_VALIDATE_MIN: 532 case NLA_VALIDATE_MAX: 533 err = nla_validate_int_range(pt, nla, extack, validate); 534 if (err) 535 return err; 536 break; 537 case NLA_VALIDATE_MASK: 538 err = nla_validate_mask(pt, nla, extack); 539 if (err) 540 return err; 541 break; 542 case NLA_VALIDATE_FUNCTION: 543 if (pt->validate) { 544 err = pt->validate(nla, extack); 545 if (err) 546 return err; 547 } 548 break; 549 } 550 551 return 0; 552 out_err: 553 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 554 "Attribute failed policy validation"); 555 return err; 556 } 557 558 static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, 559 const struct nla_policy *policy, 560 unsigned int validate, 561 struct netlink_ext_ack *extack, 562 struct nlattr **tb, unsigned int depth) 563 { 564 const struct nlattr *nla; 565 int rem; 566 567 if (depth >= MAX_POLICY_RECURSION_DEPTH) { 568 NL_SET_ERR_MSG(extack, 569 "allowed policy recursion depth exceeded"); 570 return -EINVAL; 571 } 572 573 if (tb) 574 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 575 576 nla_for_each_attr(nla, head, len, rem) { 577 u16 type = nla_type(nla); 578 579 if (type == 0 || type > maxtype) { 580 if (validate & NL_VALIDATE_MAXTYPE) { 581 NL_SET_ERR_MSG_ATTR(extack, nla, 582 "Unknown attribute type"); 583 return -EINVAL; 584 } 585 continue; 586 } 587 if (policy) { 588 int err = validate_nla(nla, maxtype, policy, 589 validate, extack, depth); 590 591 if (err < 0) 592 return err; 593 } 594 595 if (tb) 596 tb[type] = (struct nlattr *)nla; 597 } 598 599 if (unlikely(rem > 0)) { 600 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n", 601 rem, current->comm); 602 NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes"); 603 if (validate & NL_VALIDATE_TRAILING) 604 return -EINVAL; 605 } 606 607 return 0; 608 } 609 610 /** 611 * __nla_validate - Validate a stream of attributes 612 * @head: head of attribute stream 613 * @len: length of attribute stream 614 * @maxtype: maximum attribute type to be expected 615 * @policy: validation policy 616 * @validate: validation strictness 617 * @extack: extended ACK report struct 618 * 619 * Validates all attributes in the specified attribute stream against the 620 * specified policy. Validation depends on the validate flags passed, see 621 * &enum netlink_validation for more details on that. 622 * See documenation of struct nla_policy for more details. 623 * 624 * Returns 0 on success or a negative error code. 625 */ 626 int __nla_validate(const struct nlattr *head, int len, int maxtype, 627 const struct nla_policy *policy, unsigned int validate, 628 struct netlink_ext_ack *extack) 629 { 630 return __nla_validate_parse(head, len, maxtype, policy, validate, 631 extack, NULL, 0); 632 } 633 EXPORT_SYMBOL(__nla_validate); 634 635 /** 636 * nla_policy_len - Determin the max. length of a policy 637 * @policy: policy to use 638 * @n: number of policies 639 * 640 * Determines the max. length of the policy. It is currently used 641 * to allocated Netlink buffers roughly the size of the actual 642 * message. 643 * 644 * Returns 0 on success or a negative error code. 645 */ 646 int 647 nla_policy_len(const struct nla_policy *p, int n) 648 { 649 int i, len = 0; 650 651 for (i = 0; i < n; i++, p++) { 652 if (p->len) 653 len += nla_total_size(p->len); 654 else if (nla_attr_len[p->type]) 655 len += nla_total_size(nla_attr_len[p->type]); 656 else if (nla_attr_minlen[p->type]) 657 len += nla_total_size(nla_attr_minlen[p->type]); 658 } 659 660 return len; 661 } 662 EXPORT_SYMBOL(nla_policy_len); 663 664 /** 665 * __nla_parse - Parse a stream of attributes into a tb buffer 666 * @tb: destination array with maxtype+1 elements 667 * @maxtype: maximum attribute type to be expected 668 * @head: head of attribute stream 669 * @len: length of attribute stream 670 * @policy: validation policy 671 * @validate: validation strictness 672 * @extack: extended ACK pointer 673 * 674 * Parses a stream of attributes and stores a pointer to each attribute in 675 * the tb array accessible via the attribute type. 676 * Validation is controlled by the @validate parameter. 677 * 678 * Returns 0 on success or a negative error code. 679 */ 680 int __nla_parse(struct nlattr **tb, int maxtype, 681 const struct nlattr *head, int len, 682 const struct nla_policy *policy, unsigned int validate, 683 struct netlink_ext_ack *extack) 684 { 685 return __nla_validate_parse(head, len, maxtype, policy, validate, 686 extack, tb, 0); 687 } 688 EXPORT_SYMBOL(__nla_parse); 689 690 /** 691 * nla_find - Find a specific attribute in a stream of attributes 692 * @head: head of attribute stream 693 * @len: length of attribute stream 694 * @attrtype: type of attribute to look for 695 * 696 * Returns the first attribute in the stream matching the specified type. 697 */ 698 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype) 699 { 700 const struct nlattr *nla; 701 int rem; 702 703 nla_for_each_attr(nla, head, len, rem) 704 if (nla_type(nla) == attrtype) 705 return (struct nlattr *)nla; 706 707 return NULL; 708 } 709 EXPORT_SYMBOL(nla_find); 710 711 /** 712 * nla_strscpy - Copy string attribute payload into a sized buffer 713 * @dst: Where to copy the string to. 714 * @nla: Attribute to copy the string from. 715 * @dstsize: Size of destination buffer. 716 * 717 * Copies at most dstsize - 1 bytes into the destination buffer. 718 * Unlike strlcpy the destination buffer is always padded out. 719 * 720 * Return: 721 * * srclen - Returns @nla length (not including the trailing %NUL). 722 * * -E2BIG - If @dstsize is 0 or greater than U16_MAX or @nla length greater 723 * than @dstsize. 724 */ 725 ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize) 726 { 727 size_t srclen = nla_len(nla); 728 char *src = nla_data(nla); 729 ssize_t ret; 730 size_t len; 731 732 if (dstsize == 0 || WARN_ON_ONCE(dstsize > U16_MAX)) 733 return -E2BIG; 734 735 if (srclen > 0 && src[srclen - 1] == '\0') 736 srclen--; 737 738 if (srclen >= dstsize) { 739 len = dstsize - 1; 740 ret = -E2BIG; 741 } else { 742 len = srclen; 743 ret = len; 744 } 745 746 memcpy(dst, src, len); 747 /* Zero pad end of dst. */ 748 memset(dst + len, 0, dstsize - len); 749 750 return ret; 751 } 752 EXPORT_SYMBOL(nla_strscpy); 753 754 /** 755 * nla_strdup - Copy string attribute payload into a newly allocated buffer 756 * @nla: attribute to copy the string from 757 * @flags: the type of memory to allocate (see kmalloc). 758 * 759 * Returns a pointer to the allocated buffer or NULL on error. 760 */ 761 char *nla_strdup(const struct nlattr *nla, gfp_t flags) 762 { 763 size_t srclen = nla_len(nla); 764 char *src = nla_data(nla), *dst; 765 766 if (srclen > 0 && src[srclen - 1] == '\0') 767 srclen--; 768 769 dst = kmalloc(srclen + 1, flags); 770 if (dst != NULL) { 771 memcpy(dst, src, srclen); 772 dst[srclen] = '\0'; 773 } 774 return dst; 775 } 776 EXPORT_SYMBOL(nla_strdup); 777 778 /** 779 * nla_memcpy - Copy a netlink attribute into another memory area 780 * @dest: where to copy to memcpy 781 * @src: netlink attribute to copy from 782 * @count: size of the destination area 783 * 784 * Note: The number of bytes copied is limited by the length of 785 * attribute's payload. memcpy 786 * 787 * Returns the number of bytes copied. 788 */ 789 int nla_memcpy(void *dest, const struct nlattr *src, int count) 790 { 791 int minlen = min_t(int, count, nla_len(src)); 792 793 memcpy(dest, nla_data(src), minlen); 794 if (count > minlen) 795 memset(dest + minlen, 0, count - minlen); 796 797 return minlen; 798 } 799 EXPORT_SYMBOL(nla_memcpy); 800 801 /** 802 * nla_memcmp - Compare an attribute with sized memory area 803 * @nla: netlink attribute 804 * @data: memory area 805 * @size: size of memory area 806 */ 807 int nla_memcmp(const struct nlattr *nla, const void *data, 808 size_t size) 809 { 810 int d = nla_len(nla) - size; 811 812 if (d == 0) 813 d = memcmp(nla_data(nla), data, size); 814 815 return d; 816 } 817 EXPORT_SYMBOL(nla_memcmp); 818 819 /** 820 * nla_strcmp - Compare a string attribute against a string 821 * @nla: netlink string attribute 822 * @str: another string 823 */ 824 int nla_strcmp(const struct nlattr *nla, const char *str) 825 { 826 int len = strlen(str); 827 char *buf = nla_data(nla); 828 int attrlen = nla_len(nla); 829 int d; 830 831 if (attrlen > 0 && buf[attrlen - 1] == '\0') 832 attrlen--; 833 834 d = attrlen - len; 835 if (d == 0) 836 d = memcmp(nla_data(nla), str, len); 837 838 return d; 839 } 840 EXPORT_SYMBOL(nla_strcmp); 841 842 #ifdef CONFIG_NET 843 /** 844 * __nla_reserve - reserve room for attribute on the skb 845 * @skb: socket buffer to reserve room on 846 * @attrtype: attribute type 847 * @attrlen: length of attribute payload 848 * 849 * Adds a netlink attribute header to a socket buffer and reserves 850 * room for the payload but does not copy it. 851 * 852 * The caller is responsible to ensure that the skb provides enough 853 * tailroom for the attribute header and payload. 854 */ 855 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 856 { 857 struct nlattr *nla; 858 859 nla = skb_put(skb, nla_total_size(attrlen)); 860 nla->nla_type = attrtype; 861 nla->nla_len = nla_attr_size(attrlen); 862 863 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); 864 865 return nla; 866 } 867 EXPORT_SYMBOL(__nla_reserve); 868 869 /** 870 * __nla_reserve_64bit - reserve room for attribute on the skb and align it 871 * @skb: socket buffer to reserve room on 872 * @attrtype: attribute type 873 * @attrlen: length of attribute payload 874 * @padattr: attribute type for the padding 875 * 876 * Adds a netlink attribute header to a socket buffer and reserves 877 * room for the payload but does not copy it. It also ensure that this 878 * attribute will have a 64-bit aligned nla_data() area. 879 * 880 * The caller is responsible to ensure that the skb provides enough 881 * tailroom for the attribute header and payload. 882 */ 883 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype, 884 int attrlen, int padattr) 885 { 886 nla_align_64bit(skb, padattr); 887 888 return __nla_reserve(skb, attrtype, attrlen); 889 } 890 EXPORT_SYMBOL(__nla_reserve_64bit); 891 892 /** 893 * __nla_reserve_nohdr - reserve room for attribute without header 894 * @skb: socket buffer to reserve room on 895 * @attrlen: length of attribute payload 896 * 897 * Reserves room for attribute payload without a header. 898 * 899 * The caller is responsible to ensure that the skb provides enough 900 * tailroom for the payload. 901 */ 902 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) 903 { 904 return skb_put_zero(skb, NLA_ALIGN(attrlen)); 905 } 906 EXPORT_SYMBOL(__nla_reserve_nohdr); 907 908 /** 909 * nla_reserve - reserve room for attribute on the skb 910 * @skb: socket buffer to reserve room on 911 * @attrtype: attribute type 912 * @attrlen: length of attribute payload 913 * 914 * Adds a netlink attribute header to a socket buffer and reserves 915 * room for the payload but does not copy it. 916 * 917 * Returns NULL if the tailroom of the skb is insufficient to store 918 * the attribute header and payload. 919 */ 920 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 921 { 922 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) 923 return NULL; 924 925 return __nla_reserve(skb, attrtype, attrlen); 926 } 927 EXPORT_SYMBOL(nla_reserve); 928 929 /** 930 * nla_reserve_64bit - reserve room for attribute on the skb and align it 931 * @skb: socket buffer to reserve room on 932 * @attrtype: attribute type 933 * @attrlen: length of attribute payload 934 * @padattr: attribute type for the padding 935 * 936 * Adds a netlink attribute header to a socket buffer and reserves 937 * room for the payload but does not copy it. It also ensure that this 938 * attribute will have a 64-bit aligned nla_data() area. 939 * 940 * Returns NULL if the tailroom of the skb is insufficient to store 941 * the attribute header and payload. 942 */ 943 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen, 944 int padattr) 945 { 946 size_t len; 947 948 if (nla_need_padding_for_64bit(skb)) 949 len = nla_total_size_64bit(attrlen); 950 else 951 len = nla_total_size(attrlen); 952 if (unlikely(skb_tailroom(skb) < len)) 953 return NULL; 954 955 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr); 956 } 957 EXPORT_SYMBOL(nla_reserve_64bit); 958 959 /** 960 * nla_reserve_nohdr - reserve room for attribute without header 961 * @skb: socket buffer to reserve room on 962 * @attrlen: length of attribute payload 963 * 964 * Reserves room for attribute payload without a header. 965 * 966 * Returns NULL if the tailroom of the skb is insufficient to store 967 * the attribute payload. 968 */ 969 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) 970 { 971 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 972 return NULL; 973 974 return __nla_reserve_nohdr(skb, attrlen); 975 } 976 EXPORT_SYMBOL(nla_reserve_nohdr); 977 978 /** 979 * __nla_put - Add a netlink attribute to a socket buffer 980 * @skb: socket buffer to add attribute to 981 * @attrtype: attribute type 982 * @attrlen: length of attribute payload 983 * @data: head of attribute payload 984 * 985 * The caller is responsible to ensure that the skb provides enough 986 * tailroom for the attribute header and payload. 987 */ 988 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, 989 const void *data) 990 { 991 struct nlattr *nla; 992 993 nla = __nla_reserve(skb, attrtype, attrlen); 994 memcpy(nla_data(nla), data, attrlen); 995 } 996 EXPORT_SYMBOL(__nla_put); 997 998 /** 999 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it 1000 * @skb: socket buffer to add attribute to 1001 * @attrtype: attribute type 1002 * @attrlen: length of attribute payload 1003 * @data: head of attribute payload 1004 * @padattr: attribute type for the padding 1005 * 1006 * The caller is responsible to ensure that the skb provides enough 1007 * tailroom for the attribute header and payload. 1008 */ 1009 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, 1010 const void *data, int padattr) 1011 { 1012 struct nlattr *nla; 1013 1014 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr); 1015 memcpy(nla_data(nla), data, attrlen); 1016 } 1017 EXPORT_SYMBOL(__nla_put_64bit); 1018 1019 /** 1020 * __nla_put_nohdr - Add a netlink attribute without header 1021 * @skb: socket buffer to add attribute to 1022 * @attrlen: length of attribute payload 1023 * @data: head of attribute payload 1024 * 1025 * The caller is responsible to ensure that the skb provides enough 1026 * tailroom for the attribute payload. 1027 */ 1028 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) 1029 { 1030 void *start; 1031 1032 start = __nla_reserve_nohdr(skb, attrlen); 1033 memcpy(start, data, attrlen); 1034 } 1035 EXPORT_SYMBOL(__nla_put_nohdr); 1036 1037 /** 1038 * nla_put - Add a netlink attribute to a socket buffer 1039 * @skb: socket buffer to add attribute to 1040 * @attrtype: attribute type 1041 * @attrlen: length of attribute payload 1042 * @data: head of attribute payload 1043 * 1044 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1045 * the attribute header and payload. 1046 */ 1047 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) 1048 { 1049 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) 1050 return -EMSGSIZE; 1051 1052 __nla_put(skb, attrtype, attrlen, data); 1053 return 0; 1054 } 1055 EXPORT_SYMBOL(nla_put); 1056 1057 /** 1058 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it 1059 * @skb: socket buffer to add attribute to 1060 * @attrtype: attribute type 1061 * @attrlen: length of attribute payload 1062 * @data: head of attribute payload 1063 * @padattr: attribute type for the padding 1064 * 1065 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1066 * the attribute header and payload. 1067 */ 1068 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, 1069 const void *data, int padattr) 1070 { 1071 size_t len; 1072 1073 if (nla_need_padding_for_64bit(skb)) 1074 len = nla_total_size_64bit(attrlen); 1075 else 1076 len = nla_total_size(attrlen); 1077 if (unlikely(skb_tailroom(skb) < len)) 1078 return -EMSGSIZE; 1079 1080 __nla_put_64bit(skb, attrtype, attrlen, data, padattr); 1081 return 0; 1082 } 1083 EXPORT_SYMBOL(nla_put_64bit); 1084 1085 /** 1086 * nla_put_nohdr - Add a netlink attribute without header 1087 * @skb: socket buffer to add attribute to 1088 * @attrlen: length of attribute payload 1089 * @data: head of attribute payload 1090 * 1091 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1092 * the attribute payload. 1093 */ 1094 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) 1095 { 1096 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 1097 return -EMSGSIZE; 1098 1099 __nla_put_nohdr(skb, attrlen, data); 1100 return 0; 1101 } 1102 EXPORT_SYMBOL(nla_put_nohdr); 1103 1104 /** 1105 * nla_append - Add a netlink attribute without header or padding 1106 * @skb: socket buffer to add attribute to 1107 * @attrlen: length of attribute payload 1108 * @data: head of attribute payload 1109 * 1110 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1111 * the attribute payload. 1112 */ 1113 int nla_append(struct sk_buff *skb, int attrlen, const void *data) 1114 { 1115 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 1116 return -EMSGSIZE; 1117 1118 skb_put_data(skb, data, attrlen); 1119 return 0; 1120 } 1121 EXPORT_SYMBOL(nla_append); 1122 #endif 1123