| 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 documentation 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 - Determine 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 | while (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 |