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/nospec.h> 14#include <linux/skbuff.h> 15#include <linux/string.h> 16#include <linux/types.h> 17#include <net/netlink.h> 18 19/* For these data types, attribute length should be exactly the given 20 * size. However, to maintain compatibility with broken commands, if the 21 * attribute length does not match the expected size a warning is emitted 22 * to the user that the command is sending invalid data and needs to be fixed. 23 */ 24static const u8 nla_attr_len[NLA_TYPE_MAX+1] = { 25 [NLA_U8] = sizeof(u8), 26 [NLA_U16] = sizeof(u16), 27 [NLA_U32] = sizeof(u32), 28 [NLA_U64] = sizeof(u64), 29 [NLA_S8] = sizeof(s8), 30 [NLA_S16] = sizeof(s16), 31 [NLA_S32] = sizeof(s32), 32 [NLA_S64] = sizeof(s64), 33 [NLA_BE16] = sizeof(__be16), 34 [NLA_BE32] = sizeof(__be32), 35}; 36 37static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { 38 [NLA_U8] = sizeof(u8), 39 [NLA_U16] = sizeof(u16), 40 [NLA_U32] = sizeof(u32), 41 [NLA_U64] = sizeof(u64), 42 [NLA_MSECS] = sizeof(u64), 43 [NLA_NESTED] = NLA_HDRLEN, 44 [NLA_S8] = sizeof(s8), 45 [NLA_S16] = sizeof(s16), 46 [NLA_S32] = sizeof(s32), 47 [NLA_S64] = sizeof(s64), 48 [NLA_BE16] = sizeof(__be16), 49 [NLA_BE32] = sizeof(__be32), 50}; 51 52/* 53 * Nested policies might refer back to the original 54 * policy in some cases, and userspace could try to 55 * abuse that and recurse by nesting in the right 56 * ways. Limit recursion to avoid this problem. 57 */ 58#define MAX_POLICY_RECURSION_DEPTH 10 59 60static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, 61 const struct nla_policy *policy, 62 unsigned int validate, 63 struct netlink_ext_ack *extack, 64 struct nlattr **tb, unsigned int depth); 65 66static int validate_nla_bitfield32(const struct nlattr *nla, 67 const u32 valid_flags_mask) 68{ 69 const struct nla_bitfield32 *bf = nla_data(nla); 70 71 if (!valid_flags_mask) 72 return -EINVAL; 73 74 /*disallow invalid bit selector */ 75 if (bf->selector & ~valid_flags_mask) 76 return -EINVAL; 77 78 /*disallow invalid bit values */ 79 if (bf->value & ~valid_flags_mask) 80 return -EINVAL; 81 82 /*disallow valid bit values that are not selected*/ 83 if (bf->value & ~bf->selector) 84 return -EINVAL; 85 86 return 0; 87} 88 89static int nla_validate_array(const struct nlattr *head, int len, int maxtype, 90 const struct nla_policy *policy, 91 struct netlink_ext_ack *extack, 92 unsigned int validate, unsigned int depth) 93{ 94 const struct nlattr *entry; 95 int rem; 96 97 nla_for_each_attr(entry, head, len, rem) { 98 int ret; 99 100 if (nla_len(entry) == 0) 101 continue; 102 103 if (nla_len(entry) < NLA_HDRLEN) { 104 NL_SET_ERR_MSG_ATTR_POL(extack, entry, policy, 105 "Array element too short"); 106 return -ERANGE; 107 } 108 109 ret = __nla_validate_parse(nla_data(entry), nla_len(entry), 110 maxtype, policy, validate, extack, 111 NULL, depth + 1); 112 if (ret < 0) 113 return ret; 114 } 115 116 return 0; 117} 118 119void nla_get_range_unsigned(const struct nla_policy *pt, 120 struct netlink_range_validation *range) 121{ 122 WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR && 123 (pt->min < 0 || pt->max < 0)); 124 125 range->min = 0; 126 127 switch (pt->type) { 128 case NLA_U8: 129 range->max = U8_MAX; 130 break; 131 case NLA_U16: 132 case NLA_BE16: 133 case NLA_BINARY: 134 range->max = U16_MAX; 135 break; 136 case NLA_U32: 137 case NLA_BE32: 138 range->max = U32_MAX; 139 break; 140 case NLA_U64: 141 case NLA_UINT: 142 case NLA_MSECS: 143 range->max = U64_MAX; 144 break; 145 default: 146 WARN_ON_ONCE(1); 147 return; 148 } 149 150 switch (pt->validation_type) { 151 case NLA_VALIDATE_RANGE: 152 case NLA_VALIDATE_RANGE_WARN_TOO_LONG: 153 range->min = pt->min; 154 range->max = pt->max; 155 break; 156 case NLA_VALIDATE_RANGE_PTR: 157 *range = *pt->range; 158 break; 159 case NLA_VALIDATE_MIN: 160 range->min = pt->min; 161 break; 162 case NLA_VALIDATE_MAX: 163 range->max = pt->max; 164 break; 165 default: 166 break; 167 } 168} 169 170static int nla_validate_range_unsigned(const struct nla_policy *pt, 171 const struct nlattr *nla, 172 struct netlink_ext_ack *extack, 173 unsigned int validate) 174{ 175 struct netlink_range_validation range; 176 u64 value; 177 178 switch (pt->type) { 179 case NLA_U8: 180 value = nla_get_u8(nla); 181 break; 182 case NLA_U16: 183 value = nla_get_u16(nla); 184 break; 185 case NLA_U32: 186 value = nla_get_u32(nla); 187 break; 188 case NLA_U64: 189 value = nla_get_u64(nla); 190 break; 191 case NLA_UINT: 192 value = nla_get_uint(nla); 193 break; 194 case NLA_MSECS: 195 value = nla_get_u64(nla); 196 break; 197 case NLA_BINARY: 198 value = nla_len(nla); 199 break; 200 case NLA_BE16: 201 value = ntohs(nla_get_be16(nla)); 202 break; 203 case NLA_BE32: 204 value = ntohl(nla_get_be32(nla)); 205 break; 206 default: 207 return -EINVAL; 208 } 209 210 nla_get_range_unsigned(pt, &range); 211 212 if (pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG && 213 pt->type == NLA_BINARY && value > range.max) { 214 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", 215 current->comm, pt->type); 216 if (validate & NL_VALIDATE_STRICT_ATTRS) { 217 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 218 "invalid attribute length"); 219 return -EINVAL; 220 } 221 222 /* this assumes min <= max (don't validate against min) */ 223 return 0; 224 } 225 226 if (value < range.min || value > range.max) { 227 bool binary = pt->type == NLA_BINARY; 228 229 if (binary) 230 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 231 "binary attribute size out of range"); 232 else 233 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 234 "integer out of range"); 235 236 return -ERANGE; 237 } 238 239 return 0; 240} 241 242void nla_get_range_signed(const struct nla_policy *pt, 243 struct netlink_range_validation_signed *range) 244{ 245 switch (pt->type) { 246 case NLA_S8: 247 range->min = S8_MIN; 248 range->max = S8_MAX; 249 break; 250 case NLA_S16: 251 range->min = S16_MIN; 252 range->max = S16_MAX; 253 break; 254 case NLA_S32: 255 range->min = S32_MIN; 256 range->max = S32_MAX; 257 break; 258 case NLA_S64: 259 case NLA_SINT: 260 range->min = S64_MIN; 261 range->max = S64_MAX; 262 break; 263 default: 264 WARN_ON_ONCE(1); 265 return; 266 } 267 268 switch (pt->validation_type) { 269 case NLA_VALIDATE_RANGE: 270 range->min = pt->min; 271 range->max = pt->max; 272 break; 273 case NLA_VALIDATE_RANGE_PTR: 274 *range = *pt->range_signed; 275 break; 276 case NLA_VALIDATE_MIN: 277 range->min = pt->min; 278 break; 279 case NLA_VALIDATE_MAX: 280 range->max = pt->max; 281 break; 282 default: 283 break; 284 } 285} 286 287static int nla_validate_int_range_signed(const struct nla_policy *pt, 288 const struct nlattr *nla, 289 struct netlink_ext_ack *extack) 290{ 291 struct netlink_range_validation_signed range; 292 s64 value; 293 294 switch (pt->type) { 295 case NLA_S8: 296 value = nla_get_s8(nla); 297 break; 298 case NLA_S16: 299 value = nla_get_s16(nla); 300 break; 301 case NLA_S32: 302 value = nla_get_s32(nla); 303 break; 304 case NLA_S64: 305 value = nla_get_s64(nla); 306 break; 307 case NLA_SINT: 308 value = nla_get_sint(nla); 309 break; 310 default: 311 return -EINVAL; 312 } 313 314 nla_get_range_signed(pt, &range); 315 316 if (value < range.min || value > range.max) { 317 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 318 "integer out of range"); 319 return -ERANGE; 320 } 321 322 return 0; 323} 324 325static int nla_validate_int_range(const struct nla_policy *pt, 326 const struct nlattr *nla, 327 struct netlink_ext_ack *extack, 328 unsigned int validate) 329{ 330 switch (pt->type) { 331 case NLA_U8: 332 case NLA_U16: 333 case NLA_U32: 334 case NLA_U64: 335 case NLA_UINT: 336 case NLA_MSECS: 337 case NLA_BINARY: 338 case NLA_BE16: 339 case NLA_BE32: 340 return nla_validate_range_unsigned(pt, nla, extack, validate); 341 case NLA_S8: 342 case NLA_S16: 343 case NLA_S32: 344 case NLA_S64: 345 case NLA_SINT: 346 return nla_validate_int_range_signed(pt, nla, extack); 347 default: 348 WARN_ON(1); 349 return -EINVAL; 350 } 351} 352 353static int nla_validate_mask(const struct nla_policy *pt, 354 const struct nlattr *nla, 355 struct netlink_ext_ack *extack) 356{ 357 u64 value; 358 359 switch (pt->type) { 360 case NLA_U8: 361 value = nla_get_u8(nla); 362 break; 363 case NLA_U16: 364 value = nla_get_u16(nla); 365 break; 366 case NLA_U32: 367 value = nla_get_u32(nla); 368 break; 369 case NLA_U64: 370 value = nla_get_u64(nla); 371 break; 372 case NLA_UINT: 373 value = nla_get_uint(nla); 374 break; 375 case NLA_BE16: 376 value = ntohs(nla_get_be16(nla)); 377 break; 378 case NLA_BE32: 379 value = ntohl(nla_get_be32(nla)); 380 break; 381 default: 382 return -EINVAL; 383 } 384 385 if (value & ~(u64)pt->mask) { 386 NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set"); 387 return -EINVAL; 388 } 389 390 return 0; 391} 392 393static int validate_nla(const struct nlattr *nla, int maxtype, 394 const struct nla_policy *policy, unsigned int validate, 395 struct netlink_ext_ack *extack, unsigned int depth) 396{ 397 u16 strict_start_type = policy[0].strict_start_type; 398 const struct nla_policy *pt; 399 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); 400 int err = -ERANGE; 401 402 if (strict_start_type && type >= strict_start_type) 403 validate |= NL_VALIDATE_STRICT; 404 405 if (type <= 0 || type > maxtype) 406 return 0; 407 408 type = array_index_nospec(type, maxtype + 1); 409 pt = &policy[type]; 410 411 BUG_ON(pt->type > NLA_TYPE_MAX); 412 413 if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) { 414 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", 415 current->comm, type); 416 if (validate & NL_VALIDATE_STRICT_ATTRS) { 417 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 418 "invalid attribute length"); 419 return -EINVAL; 420 } 421 } 422 423 if (validate & NL_VALIDATE_NESTED) { 424 if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) && 425 !(nla->nla_type & NLA_F_NESTED)) { 426 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 427 "NLA_F_NESTED is missing"); 428 return -EINVAL; 429 } 430 if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY && 431 pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) { 432 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 433 "NLA_F_NESTED not expected"); 434 return -EINVAL; 435 } 436 } 437 438 switch (pt->type) { 439 case NLA_REJECT: 440 if (extack && pt->reject_message) { 441 NL_SET_BAD_ATTR(extack, nla); 442 extack->_msg = pt->reject_message; 443 return -EINVAL; 444 } 445 err = -EINVAL; 446 goto out_err; 447 448 case NLA_FLAG: 449 if (attrlen > 0) 450 goto out_err; 451 break; 452 453 case NLA_SINT: 454 case NLA_UINT: 455 if (attrlen != sizeof(u32) && attrlen != sizeof(u64)) { 456 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 457 "invalid attribute length"); 458 return -EINVAL; 459 } 460 break; 461 462 case NLA_BITFIELD32: 463 if (attrlen != sizeof(struct nla_bitfield32)) 464 goto out_err; 465 466 err = validate_nla_bitfield32(nla, pt->bitfield32_valid); 467 if (err) 468 goto out_err; 469 break; 470 471 case NLA_NUL_STRING: 472 if (pt->len) 473 minlen = min_t(int, attrlen, pt->len + 1); 474 else 475 minlen = attrlen; 476 477 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) { 478 err = -EINVAL; 479 goto out_err; 480 } 481 fallthrough; 482 483 case NLA_STRING: 484 if (attrlen < 1) 485 goto out_err; 486 487 if (pt->len) { 488 char *buf = nla_data(nla); 489 490 if (buf[attrlen - 1] == '\0') 491 attrlen--; 492 493 if (attrlen > pt->len) 494 goto out_err; 495 } 496 break; 497 498 case NLA_BINARY: 499 if (pt->len && attrlen > pt->len) 500 goto out_err; 501 break; 502 503 case NLA_NESTED: 504 /* a nested attributes is allowed to be empty; if its not, 505 * it must have a size of at least NLA_HDRLEN. 506 */ 507 if (attrlen == 0) 508 break; 509 if (attrlen < NLA_HDRLEN) 510 goto out_err; 511 if (pt->nested_policy) { 512 err = __nla_validate_parse(nla_data(nla), nla_len(nla), 513 pt->len, pt->nested_policy, 514 validate, extack, NULL, 515 depth + 1); 516 if (err < 0) { 517 /* 518 * return directly to preserve the inner 519 * error message/attribute pointer 520 */ 521 return err; 522 } 523 } 524 break; 525 case NLA_NESTED_ARRAY: 526 /* a nested array attribute is allowed to be empty; if its not, 527 * it must have a size of at least NLA_HDRLEN. 528 */ 529 if (attrlen == 0) 530 break; 531 if (attrlen < NLA_HDRLEN) 532 goto out_err; 533 if (pt->nested_policy) { 534 int err; 535 536 err = nla_validate_array(nla_data(nla), nla_len(nla), 537 pt->len, pt->nested_policy, 538 extack, validate, depth); 539 if (err < 0) { 540 /* 541 * return directly to preserve the inner 542 * error message/attribute pointer 543 */ 544 return err; 545 } 546 } 547 break; 548 549 case NLA_UNSPEC: 550 if (validate & NL_VALIDATE_UNSPEC) { 551 NL_SET_ERR_MSG_ATTR(extack, nla, 552 "Unsupported attribute"); 553 return -EINVAL; 554 } 555 if (attrlen < pt->len) 556 goto out_err; 557 break; 558 559 default: 560 if (pt->len) 561 minlen = pt->len; 562 else 563 minlen = nla_attr_minlen[pt->type]; 564 565 if (attrlen < minlen) 566 goto out_err; 567 } 568 569 /* further validation */ 570 switch (pt->validation_type) { 571 case NLA_VALIDATE_NONE: 572 /* nothing to do */ 573 break; 574 case NLA_VALIDATE_RANGE_PTR: 575 case NLA_VALIDATE_RANGE: 576 case NLA_VALIDATE_RANGE_WARN_TOO_LONG: 577 case NLA_VALIDATE_MIN: 578 case NLA_VALIDATE_MAX: 579 err = nla_validate_int_range(pt, nla, extack, validate); 580 if (err) 581 return err; 582 break; 583 case NLA_VALIDATE_MASK: 584 err = nla_validate_mask(pt, nla, extack); 585 if (err) 586 return err; 587 break; 588 case NLA_VALIDATE_FUNCTION: 589 if (pt->validate) { 590 err = pt->validate(nla, extack); 591 if (err) 592 return err; 593 } 594 break; 595 } 596 597 return 0; 598out_err: 599 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, 600 "Attribute failed policy validation"); 601 return err; 602} 603 604static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, 605 const struct nla_policy *policy, 606 unsigned int validate, 607 struct netlink_ext_ack *extack, 608 struct nlattr **tb, unsigned int depth) 609{ 610 const struct nlattr *nla; 611 int rem; 612 613 if (depth >= MAX_POLICY_RECURSION_DEPTH) { 614 NL_SET_ERR_MSG(extack, 615 "allowed policy recursion depth exceeded"); 616 return -EINVAL; 617 } 618 619 if (tb) 620 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 621 622 nla_for_each_attr(nla, head, len, rem) { 623 u16 type = nla_type(nla); 624 625 if (type == 0 || type > maxtype) { 626 if (validate & NL_VALIDATE_MAXTYPE) { 627 NL_SET_ERR_MSG_ATTR(extack, nla, 628 "Unknown attribute type"); 629 return -EINVAL; 630 } 631 continue; 632 } 633 type = array_index_nospec(type, maxtype + 1); 634 if (policy) { 635 int err = validate_nla(nla, maxtype, policy, 636 validate, extack, depth); 637 638 if (err < 0) 639 return err; 640 } 641 642 if (tb) 643 tb[type] = (struct nlattr *)nla; 644 } 645 646 if (unlikely(rem > 0)) { 647 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n", 648 rem, current->comm); 649 NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes"); 650 if (validate & NL_VALIDATE_TRAILING) 651 return -EINVAL; 652 } 653 654 return 0; 655} 656 657/** 658 * __nla_validate - Validate a stream of attributes 659 * @head: head of attribute stream 660 * @len: length of attribute stream 661 * @maxtype: maximum attribute type to be expected 662 * @policy: validation policy 663 * @validate: validation strictness 664 * @extack: extended ACK report struct 665 * 666 * Validates all attributes in the specified attribute stream against the 667 * specified policy. Validation depends on the validate flags passed, see 668 * &enum netlink_validation for more details on that. 669 * See documentation of struct nla_policy for more details. 670 * 671 * Returns 0 on success or a negative error code. 672 */ 673int __nla_validate(const struct nlattr *head, int len, int maxtype, 674 const struct nla_policy *policy, unsigned int validate, 675 struct netlink_ext_ack *extack) 676{ 677 return __nla_validate_parse(head, len, maxtype, policy, validate, 678 extack, NULL, 0); 679} 680EXPORT_SYMBOL(__nla_validate); 681 682/** 683 * nla_policy_len - Determine the max. length of a policy 684 * @p: policy to use 685 * @n: number of policies 686 * 687 * Determines the max. length of the policy. It is currently used 688 * to allocated Netlink buffers roughly the size of the actual 689 * message. 690 * 691 * Returns 0 on success or a negative error code. 692 */ 693int 694nla_policy_len(const struct nla_policy *p, int n) 695{ 696 int i, len = 0; 697 698 for (i = 0; i < n; i++, p++) { 699 if (p->len) 700 len += nla_total_size(p->len); 701 else if (nla_attr_len[p->type]) 702 len += nla_total_size(nla_attr_len[p->type]); 703 else if (nla_attr_minlen[p->type]) 704 len += nla_total_size(nla_attr_minlen[p->type]); 705 } 706 707 return len; 708} 709EXPORT_SYMBOL(nla_policy_len); 710 711/** 712 * __nla_parse - Parse a stream of attributes into a tb buffer 713 * @tb: destination array with maxtype+1 elements 714 * @maxtype: maximum attribute type to be expected 715 * @head: head of attribute stream 716 * @len: length of attribute stream 717 * @policy: validation policy 718 * @validate: validation strictness 719 * @extack: extended ACK pointer 720 * 721 * Parses a stream of attributes and stores a pointer to each attribute in 722 * the tb array accessible via the attribute type. 723 * Validation is controlled by the @validate parameter. 724 * 725 * Returns 0 on success or a negative error code. 726 */ 727int __nla_parse(struct nlattr **tb, int maxtype, 728 const struct nlattr *head, int len, 729 const struct nla_policy *policy, unsigned int validate, 730 struct netlink_ext_ack *extack) 731{ 732 return __nla_validate_parse(head, len, maxtype, policy, validate, 733 extack, tb, 0); 734} 735EXPORT_SYMBOL(__nla_parse); 736 737/** 738 * nla_find - Find a specific attribute in a stream of attributes 739 * @head: head of attribute stream 740 * @len: length of attribute stream 741 * @attrtype: type of attribute to look for 742 * 743 * Returns the first attribute in the stream matching the specified type. 744 */ 745struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype) 746{ 747 const struct nlattr *nla; 748 int rem; 749 750 nla_for_each_attr(nla, head, len, rem) 751 if (nla_type(nla) == attrtype) 752 return (struct nlattr *)nla; 753 754 return NULL; 755} 756EXPORT_SYMBOL(nla_find); 757 758/** 759 * nla_strscpy - Copy string attribute payload into a sized buffer 760 * @dst: Where to copy the string to. 761 * @nla: Attribute to copy the string from. 762 * @dstsize: Size of destination buffer. 763 * 764 * Copies at most dstsize - 1 bytes into the destination buffer. 765 * Unlike strscpy() the destination buffer is always padded out. 766 * 767 * Return: 768 * * srclen - Returns @nla length (not including the trailing %NUL). 769 * * -E2BIG - If @dstsize is 0 or greater than U16_MAX or @nla length greater 770 * than @dstsize. 771 */ 772ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize) 773{ 774 size_t srclen = nla_len(nla); 775 char *src = nla_data(nla); 776 ssize_t ret; 777 size_t len; 778 779 if (dstsize == 0 || WARN_ON_ONCE(dstsize > U16_MAX)) 780 return -E2BIG; 781 782 if (srclen > 0 && src[srclen - 1] == '\0') 783 srclen--; 784 785 if (srclen >= dstsize) { 786 len = dstsize - 1; 787 ret = -E2BIG; 788 } else { 789 len = srclen; 790 ret = len; 791 } 792 793 memcpy(dst, src, len); 794 /* Zero pad end of dst. */ 795 memset(dst + len, 0, dstsize - len); 796 797 return ret; 798} 799EXPORT_SYMBOL(nla_strscpy); 800 801/** 802 * nla_strdup - Copy string attribute payload into a newly allocated buffer 803 * @nla: attribute to copy the string from 804 * @flags: the type of memory to allocate (see kmalloc). 805 * 806 * Returns a pointer to the allocated buffer or NULL on error. 807 */ 808char *nla_strdup(const struct nlattr *nla, gfp_t flags) 809{ 810 size_t srclen = nla_len(nla); 811 char *src = nla_data(nla), *dst; 812 813 if (srclen > 0 && src[srclen - 1] == '\0') 814 srclen--; 815 816 dst = kmalloc(srclen + 1, flags); 817 if (dst != NULL) { 818 memcpy(dst, src, srclen); 819 dst[srclen] = '\0'; 820 } 821 return dst; 822} 823EXPORT_SYMBOL(nla_strdup); 824 825/** 826 * nla_memcpy - Copy a netlink attribute into another memory area 827 * @dest: where to copy to memcpy 828 * @src: netlink attribute to copy from 829 * @count: size of the destination area 830 * 831 * Note: The number of bytes copied is limited by the length of 832 * attribute's payload. memcpy 833 * 834 * Returns the number of bytes copied. 835 */ 836int nla_memcpy(void *dest, const struct nlattr *src, int count) 837{ 838 int minlen = min_t(int, count, nla_len(src)); 839 840 memcpy(dest, nla_data(src), minlen); 841 if (count > minlen) 842 memset(dest + minlen, 0, count - minlen); 843 844 return minlen; 845} 846EXPORT_SYMBOL(nla_memcpy); 847 848/** 849 * nla_memcmp - Compare an attribute with sized memory area 850 * @nla: netlink attribute 851 * @data: memory area 852 * @size: size of memory area 853 */ 854int nla_memcmp(const struct nlattr *nla, const void *data, 855 size_t size) 856{ 857 int d = nla_len(nla) - size; 858 859 if (d == 0) 860 d = memcmp(nla_data(nla), data, size); 861 862 return d; 863} 864EXPORT_SYMBOL(nla_memcmp); 865 866/** 867 * nla_strcmp - Compare a string attribute against a string 868 * @nla: netlink string attribute 869 * @str: another string 870 */ 871int nla_strcmp(const struct nlattr *nla, const char *str) 872{ 873 int len = strlen(str); 874 char *buf = nla_data(nla); 875 int attrlen = nla_len(nla); 876 int d; 877 878 while (attrlen > 0 && buf[attrlen - 1] == '\0') 879 attrlen--; 880 881 d = attrlen - len; 882 if (d == 0) 883 d = memcmp(nla_data(nla), str, len); 884 885 return d; 886} 887EXPORT_SYMBOL(nla_strcmp); 888 889#ifdef CONFIG_NET 890/** 891 * __nla_reserve - reserve room for attribute on the skb 892 * @skb: socket buffer to reserve room on 893 * @attrtype: attribute type 894 * @attrlen: length of attribute payload 895 * 896 * Adds a netlink attribute header to a socket buffer and reserves 897 * room for the payload but does not copy it. 898 * 899 * The caller is responsible to ensure that the skb provides enough 900 * tailroom for the attribute header and payload. 901 */ 902struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 903{ 904 struct nlattr *nla; 905 906 nla = skb_put(skb, nla_total_size(attrlen)); 907 nla->nla_type = attrtype; 908 nla->nla_len = nla_attr_size(attrlen); 909 910 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); 911 912 return nla; 913} 914EXPORT_SYMBOL(__nla_reserve); 915 916/** 917 * __nla_reserve_64bit - reserve room for attribute on the skb and align it 918 * @skb: socket buffer to reserve room on 919 * @attrtype: attribute type 920 * @attrlen: length of attribute payload 921 * @padattr: attribute type for the padding 922 * 923 * Adds a netlink attribute header to a socket buffer and reserves 924 * room for the payload but does not copy it. It also ensure that this 925 * attribute will have a 64-bit aligned nla_data() area. 926 * 927 * The caller is responsible to ensure that the skb provides enough 928 * tailroom for the attribute header and payload. 929 */ 930struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype, 931 int attrlen, int padattr) 932{ 933 nla_align_64bit(skb, padattr); 934 935 return __nla_reserve(skb, attrtype, attrlen); 936} 937EXPORT_SYMBOL(__nla_reserve_64bit); 938 939/** 940 * __nla_reserve_nohdr - reserve room for attribute without header 941 * @skb: socket buffer to reserve room on 942 * @attrlen: length of attribute payload 943 * 944 * Reserves room for attribute payload without a header. 945 * 946 * The caller is responsible to ensure that the skb provides enough 947 * tailroom for the payload. 948 */ 949void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) 950{ 951 return skb_put_zero(skb, NLA_ALIGN(attrlen)); 952} 953EXPORT_SYMBOL(__nla_reserve_nohdr); 954 955/** 956 * nla_reserve - reserve room for attribute on the skb 957 * @skb: socket buffer to reserve room on 958 * @attrtype: attribute type 959 * @attrlen: length of attribute payload 960 * 961 * Adds a netlink attribute header to a socket buffer and reserves 962 * room for the payload but does not copy it. 963 * 964 * Returns NULL if the tailroom of the skb is insufficient to store 965 * the attribute header and payload. 966 */ 967struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 968{ 969 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) 970 return NULL; 971 972 return __nla_reserve(skb, attrtype, attrlen); 973} 974EXPORT_SYMBOL(nla_reserve); 975 976/** 977 * nla_reserve_64bit - reserve room for attribute on the skb and align it 978 * @skb: socket buffer to reserve room on 979 * @attrtype: attribute type 980 * @attrlen: length of attribute payload 981 * @padattr: attribute type for the padding 982 * 983 * Adds a netlink attribute header to a socket buffer and reserves 984 * room for the payload but does not copy it. It also ensure that this 985 * attribute will have a 64-bit aligned nla_data() area. 986 * 987 * Returns NULL if the tailroom of the skb is insufficient to store 988 * the attribute header and payload. 989 */ 990struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen, 991 int padattr) 992{ 993 size_t len; 994 995 if (nla_need_padding_for_64bit(skb)) 996 len = nla_total_size_64bit(attrlen); 997 else 998 len = nla_total_size(attrlen); 999 if (unlikely(skb_tailroom(skb) < len)) 1000 return NULL; 1001 1002 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr); 1003} 1004EXPORT_SYMBOL(nla_reserve_64bit); 1005 1006/** 1007 * nla_reserve_nohdr - reserve room for attribute without header 1008 * @skb: socket buffer to reserve room on 1009 * @attrlen: length of attribute payload 1010 * 1011 * Reserves room for attribute payload without a header. 1012 * 1013 * Returns NULL if the tailroom of the skb is insufficient to store 1014 * the attribute payload. 1015 */ 1016void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) 1017{ 1018 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 1019 return NULL; 1020 1021 return __nla_reserve_nohdr(skb, attrlen); 1022} 1023EXPORT_SYMBOL(nla_reserve_nohdr); 1024 1025/** 1026 * __nla_put - Add a netlink attribute to a socket buffer 1027 * @skb: socket buffer to add attribute to 1028 * @attrtype: attribute type 1029 * @attrlen: length of attribute payload 1030 * @data: head of attribute payload 1031 * 1032 * The caller is responsible to ensure that the skb provides enough 1033 * tailroom for the attribute header and payload. 1034 */ 1035void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, 1036 const void *data) 1037{ 1038 struct nlattr *nla; 1039 1040 nla = __nla_reserve(skb, attrtype, attrlen); 1041 memcpy(nla_data(nla), data, attrlen); 1042} 1043EXPORT_SYMBOL(__nla_put); 1044 1045/** 1046 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it 1047 * @skb: socket buffer to add attribute to 1048 * @attrtype: attribute type 1049 * @attrlen: length of attribute payload 1050 * @data: head of attribute payload 1051 * @padattr: attribute type for the padding 1052 * 1053 * The caller is responsible to ensure that the skb provides enough 1054 * tailroom for the attribute header and payload. 1055 */ 1056void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, 1057 const void *data, int padattr) 1058{ 1059 struct nlattr *nla; 1060 1061 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr); 1062 memcpy(nla_data(nla), data, attrlen); 1063} 1064EXPORT_SYMBOL(__nla_put_64bit); 1065 1066/** 1067 * __nla_put_nohdr - Add a netlink attribute without header 1068 * @skb: socket buffer to add attribute to 1069 * @attrlen: length of attribute payload 1070 * @data: head of attribute payload 1071 * 1072 * The caller is responsible to ensure that the skb provides enough 1073 * tailroom for the attribute payload. 1074 */ 1075void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) 1076{ 1077 void *start; 1078 1079 start = __nla_reserve_nohdr(skb, attrlen); 1080 memcpy(start, data, attrlen); 1081} 1082EXPORT_SYMBOL(__nla_put_nohdr); 1083 1084/** 1085 * nla_put - Add a netlink attribute to a socket buffer 1086 * @skb: socket buffer to add attribute to 1087 * @attrtype: attribute type 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 header and payload. 1093 */ 1094int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) 1095{ 1096 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) 1097 return -EMSGSIZE; 1098 1099 __nla_put(skb, attrtype, attrlen, data); 1100 return 0; 1101} 1102EXPORT_SYMBOL(nla_put); 1103 1104/** 1105 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it 1106 * @skb: socket buffer to add attribute to 1107 * @attrtype: attribute type 1108 * @attrlen: length of attribute payload 1109 * @data: head of attribute payload 1110 * @padattr: attribute type for the padding 1111 * 1112 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1113 * the attribute header and payload. 1114 */ 1115int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, 1116 const void *data, int padattr) 1117{ 1118 size_t len; 1119 1120 if (nla_need_padding_for_64bit(skb)) 1121 len = nla_total_size_64bit(attrlen); 1122 else 1123 len = nla_total_size(attrlen); 1124 if (unlikely(skb_tailroom(skb) < len)) 1125 return -EMSGSIZE; 1126 1127 __nla_put_64bit(skb, attrtype, attrlen, data, padattr); 1128 return 0; 1129} 1130EXPORT_SYMBOL(nla_put_64bit); 1131 1132/** 1133 * nla_put_nohdr - Add a netlink attribute without header 1134 * @skb: socket buffer to add attribute to 1135 * @attrlen: length of attribute payload 1136 * @data: head of attribute payload 1137 * 1138 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1139 * the attribute payload. 1140 */ 1141int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) 1142{ 1143 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 1144 return -EMSGSIZE; 1145 1146 __nla_put_nohdr(skb, attrlen, data); 1147 return 0; 1148} 1149EXPORT_SYMBOL(nla_put_nohdr); 1150 1151/** 1152 * nla_append - Add a netlink attribute without header or padding 1153 * @skb: socket buffer to add attribute to 1154 * @attrlen: length of attribute payload 1155 * @data: head of attribute payload 1156 * 1157 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store 1158 * the attribute payload. 1159 */ 1160int nla_append(struct sk_buff *skb, int attrlen, const void *data) 1161{ 1162 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) 1163 return -EMSGSIZE; 1164 1165 skb_put_data(skb, data, attrlen); 1166 return 0; 1167} 1168EXPORT_SYMBOL(nla_append); 1169#endif 1170