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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
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};
34
35static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
36 [NLA_U8] = sizeof(u8),
37 [NLA_U16] = sizeof(u16),
38 [NLA_U32] = sizeof(u32),
39 [NLA_U64] = sizeof(u64),
40 [NLA_MSECS] = sizeof(u64),
41 [NLA_NESTED] = NLA_HDRLEN,
42 [NLA_S8] = sizeof(s8),
43 [NLA_S16] = sizeof(s16),
44 [NLA_S32] = sizeof(s32),
45 [NLA_S64] = sizeof(s64),
46};
47
48/*
49 * Nested policies might refer back to the original
50 * policy in some cases, and userspace could try to
51 * abuse that and recurse by nesting in the right
52 * ways. Limit recursion to avoid this problem.
53 */
54#define MAX_POLICY_RECURSION_DEPTH 10
55
56static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
57 const struct nla_policy *policy,
58 unsigned int validate,
59 struct netlink_ext_ack *extack,
60 struct nlattr **tb, unsigned int depth);
61
62static int validate_nla_bitfield32(const struct nlattr *nla,
63 const u32 valid_flags_mask)
64{
65 const struct nla_bitfield32 *bf = nla_data(nla);
66
67 if (!valid_flags_mask)
68 return -EINVAL;
69
70 /*disallow invalid bit selector */
71 if (bf->selector & ~valid_flags_mask)
72 return -EINVAL;
73
74 /*disallow invalid bit values */
75 if (bf->value & ~valid_flags_mask)
76 return -EINVAL;
77
78 /*disallow valid bit values that are not selected*/
79 if (bf->value & ~bf->selector)
80 return -EINVAL;
81
82 return 0;
83}
84
85static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
86 const struct nla_policy *policy,
87 struct netlink_ext_ack *extack,
88 unsigned int validate, unsigned int depth)
89{
90 const struct nlattr *entry;
91 int rem;
92
93 nla_for_each_attr(entry, head, len, rem) {
94 int ret;
95
96 if (nla_len(entry) == 0)
97 continue;
98
99 if (nla_len(entry) < NLA_HDRLEN) {
100 NL_SET_ERR_MSG_ATTR_POL(extack, entry, policy,
101 "Array element too short");
102 return -ERANGE;
103 }
104
105 ret = __nla_validate_parse(nla_data(entry), nla_len(entry),
106 maxtype, policy, validate, extack,
107 NULL, depth + 1);
108 if (ret < 0)
109 return ret;
110 }
111
112 return 0;
113}
114
115void nla_get_range_unsigned(const struct nla_policy *pt,
116 struct netlink_range_validation *range)
117{
118 WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR &&
119 (pt->min < 0 || pt->max < 0));
120
121 range->min = 0;
122
123 switch (pt->type) {
124 case NLA_U8:
125 range->max = U8_MAX;
126 break;
127 case NLA_U16:
128 case NLA_BE16:
129 case NLA_BINARY:
130 range->max = U16_MAX;
131 break;
132 case NLA_U32:
133 case NLA_BE32:
134 range->max = U32_MAX;
135 break;
136 case NLA_U64:
137 case NLA_MSECS:
138 range->max = U64_MAX;
139 break;
140 default:
141 WARN_ON_ONCE(1);
142 return;
143 }
144
145 switch (pt->validation_type) {
146 case NLA_VALIDATE_RANGE:
147 case NLA_VALIDATE_RANGE_WARN_TOO_LONG:
148 range->min = pt->min;
149 range->max = pt->max;
150 break;
151 case NLA_VALIDATE_RANGE_PTR:
152 *range = *pt->range;
153 break;
154 case NLA_VALIDATE_MIN:
155 range->min = pt->min;
156 break;
157 case NLA_VALIDATE_MAX:
158 range->max = pt->max;
159 break;
160 default:
161 break;
162 }
163}
164
165static int nla_validate_range_unsigned(const struct nla_policy *pt,
166 const struct nlattr *nla,
167 struct netlink_ext_ack *extack,
168 unsigned int validate)
169{
170 struct netlink_range_validation range;
171 u64 value;
172
173 switch (pt->type) {
174 case NLA_U8:
175 value = nla_get_u8(nla);
176 break;
177 case NLA_U16:
178 value = nla_get_u16(nla);
179 break;
180 case NLA_U32:
181 value = nla_get_u32(nla);
182 break;
183 case NLA_U64:
184 value = nla_get_u64(nla);
185 break;
186 case NLA_MSECS:
187 value = nla_get_u64(nla);
188 break;
189 case NLA_BINARY:
190 value = nla_len(nla);
191 break;
192 case NLA_BE16:
193 value = ntohs(nla_get_be16(nla));
194 break;
195 case NLA_BE32:
196 value = ntohl(nla_get_be32(nla));
197 break;
198 default:
199 return -EINVAL;
200 }
201
202 nla_get_range_unsigned(pt, &range);
203
204 if (pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG &&
205 pt->type == NLA_BINARY && value > range.max) {
206 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
207 current->comm, pt->type);
208 if (validate & NL_VALIDATE_STRICT_ATTRS) {
209 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
210 "invalid attribute length");
211 return -EINVAL;
212 }
213
214 /* this assumes min <= max (don't validate against min) */
215 return 0;
216 }
217
218 if (value < range.min || value > range.max) {
219 bool binary = pt->type == NLA_BINARY;
220
221 if (binary)
222 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
223 "binary attribute size out of range");
224 else
225 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
226 "integer out of range");
227
228 return -ERANGE;
229 }
230
231 return 0;
232}
233
234void nla_get_range_signed(const struct nla_policy *pt,
235 struct netlink_range_validation_signed *range)
236{
237 switch (pt->type) {
238 case NLA_S8:
239 range->min = S8_MIN;
240 range->max = S8_MAX;
241 break;
242 case NLA_S16:
243 range->min = S16_MIN;
244 range->max = S16_MAX;
245 break;
246 case NLA_S32:
247 range->min = S32_MIN;
248 range->max = S32_MAX;
249 break;
250 case NLA_S64:
251 range->min = S64_MIN;
252 range->max = S64_MAX;
253 break;
254 default:
255 WARN_ON_ONCE(1);
256 return;
257 }
258
259 switch (pt->validation_type) {
260 case NLA_VALIDATE_RANGE:
261 range->min = pt->min;
262 range->max = pt->max;
263 break;
264 case NLA_VALIDATE_RANGE_PTR:
265 *range = *pt->range_signed;
266 break;
267 case NLA_VALIDATE_MIN:
268 range->min = pt->min;
269 break;
270 case NLA_VALIDATE_MAX:
271 range->max = pt->max;
272 break;
273 default:
274 break;
275 }
276}
277
278static int nla_validate_int_range_signed(const struct nla_policy *pt,
279 const struct nlattr *nla,
280 struct netlink_ext_ack *extack)
281{
282 struct netlink_range_validation_signed range;
283 s64 value;
284
285 switch (pt->type) {
286 case NLA_S8:
287 value = nla_get_s8(nla);
288 break;
289 case NLA_S16:
290 value = nla_get_s16(nla);
291 break;
292 case NLA_S32:
293 value = nla_get_s32(nla);
294 break;
295 case NLA_S64:
296 value = nla_get_s64(nla);
297 break;
298 default:
299 return -EINVAL;
300 }
301
302 nla_get_range_signed(pt, &range);
303
304 if (value < range.min || value > range.max) {
305 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
306 "integer out of range");
307 return -ERANGE;
308 }
309
310 return 0;
311}
312
313static int nla_validate_int_range(const struct nla_policy *pt,
314 const struct nlattr *nla,
315 struct netlink_ext_ack *extack,
316 unsigned int validate)
317{
318 switch (pt->type) {
319 case NLA_U8:
320 case NLA_U16:
321 case NLA_U32:
322 case NLA_U64:
323 case NLA_MSECS:
324 case NLA_BINARY:
325 case NLA_BE16:
326 case NLA_BE32:
327 return nla_validate_range_unsigned(pt, nla, extack, validate);
328 case NLA_S8:
329 case NLA_S16:
330 case NLA_S32:
331 case NLA_S64:
332 return nla_validate_int_range_signed(pt, nla, extack);
333 default:
334 WARN_ON(1);
335 return -EINVAL;
336 }
337}
338
339static int nla_validate_mask(const struct nla_policy *pt,
340 const struct nlattr *nla,
341 struct netlink_ext_ack *extack)
342{
343 u64 value;
344
345 switch (pt->type) {
346 case NLA_U8:
347 value = nla_get_u8(nla);
348 break;
349 case NLA_U16:
350 value = nla_get_u16(nla);
351 break;
352 case NLA_U32:
353 value = nla_get_u32(nla);
354 break;
355 case NLA_U64:
356 value = nla_get_u64(nla);
357 break;
358 default:
359 return -EINVAL;
360 }
361
362 if (value & ~(u64)pt->mask) {
363 NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set");
364 return -EINVAL;
365 }
366
367 return 0;
368}
369
370static int validate_nla(const struct nlattr *nla, int maxtype,
371 const struct nla_policy *policy, unsigned int validate,
372 struct netlink_ext_ack *extack, unsigned int depth)
373{
374 u16 strict_start_type = policy[0].strict_start_type;
375 const struct nla_policy *pt;
376 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
377 int err = -ERANGE;
378
379 if (strict_start_type && type >= strict_start_type)
380 validate |= NL_VALIDATE_STRICT;
381
382 if (type <= 0 || type > maxtype)
383 return 0;
384
385 type = array_index_nospec(type, maxtype + 1);
386 pt = &policy[type];
387
388 BUG_ON(pt->type > NLA_TYPE_MAX);
389
390 if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) {
391 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
392 current->comm, type);
393 if (validate & NL_VALIDATE_STRICT_ATTRS) {
394 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
395 "invalid attribute length");
396 return -EINVAL;
397 }
398 }
399
400 if (validate & NL_VALIDATE_NESTED) {
401 if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&
402 !(nla->nla_type & NLA_F_NESTED)) {
403 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
404 "NLA_F_NESTED is missing");
405 return -EINVAL;
406 }
407 if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&
408 pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {
409 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
410 "NLA_F_NESTED not expected");
411 return -EINVAL;
412 }
413 }
414
415 switch (pt->type) {
416 case NLA_REJECT:
417 if (extack && pt->reject_message) {
418 NL_SET_BAD_ATTR(extack, nla);
419 extack->_msg = pt->reject_message;
420 return -EINVAL;
421 }
422 err = -EINVAL;
423 goto out_err;
424
425 case NLA_FLAG:
426 if (attrlen > 0)
427 goto out_err;
428 break;
429
430 case NLA_BITFIELD32:
431 if (attrlen != sizeof(struct nla_bitfield32))
432 goto out_err;
433
434 err = validate_nla_bitfield32(nla, pt->bitfield32_valid);
435 if (err)
436 goto out_err;
437 break;
438
439 case NLA_NUL_STRING:
440 if (pt->len)
441 minlen = min_t(int, attrlen, pt->len + 1);
442 else
443 minlen = attrlen;
444
445 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
446 err = -EINVAL;
447 goto out_err;
448 }
449 fallthrough;
450
451 case NLA_STRING:
452 if (attrlen < 1)
453 goto out_err;
454
455 if (pt->len) {
456 char *buf = nla_data(nla);
457
458 if (buf[attrlen - 1] == '\0')
459 attrlen--;
460
461 if (attrlen > pt->len)
462 goto out_err;
463 }
464 break;
465
466 case NLA_BINARY:
467 if (pt->len && attrlen > pt->len)
468 goto out_err;
469 break;
470
471 case NLA_NESTED:
472 /* a nested attributes is allowed to be empty; if its not,
473 * it must have a size of at least NLA_HDRLEN.
474 */
475 if (attrlen == 0)
476 break;
477 if (attrlen < NLA_HDRLEN)
478 goto out_err;
479 if (pt->nested_policy) {
480 err = __nla_validate_parse(nla_data(nla), nla_len(nla),
481 pt->len, pt->nested_policy,
482 validate, extack, NULL,
483 depth + 1);
484 if (err < 0) {
485 /*
486 * return directly to preserve the inner
487 * error message/attribute pointer
488 */
489 return err;
490 }
491 }
492 break;
493 case NLA_NESTED_ARRAY:
494 /* a nested array attribute is allowed to be empty; if its not,
495 * it must have a size of at least NLA_HDRLEN.
496 */
497 if (attrlen == 0)
498 break;
499 if (attrlen < NLA_HDRLEN)
500 goto out_err;
501 if (pt->nested_policy) {
502 int err;
503
504 err = nla_validate_array(nla_data(nla), nla_len(nla),
505 pt->len, pt->nested_policy,
506 extack, validate, depth);
507 if (err < 0) {
508 /*
509 * return directly to preserve the inner
510 * error message/attribute pointer
511 */
512 return err;
513 }
514 }
515 break;
516
517 case NLA_UNSPEC:
518 if (validate & NL_VALIDATE_UNSPEC) {
519 NL_SET_ERR_MSG_ATTR(extack, nla,
520 "Unsupported attribute");
521 return -EINVAL;
522 }
523 if (attrlen < pt->len)
524 goto out_err;
525 break;
526
527 default:
528 if (pt->len)
529 minlen = pt->len;
530 else
531 minlen = nla_attr_minlen[pt->type];
532
533 if (attrlen < minlen)
534 goto out_err;
535 }
536
537 /* further validation */
538 switch (pt->validation_type) {
539 case NLA_VALIDATE_NONE:
540 /* nothing to do */
541 break;
542 case NLA_VALIDATE_RANGE_PTR:
543 case NLA_VALIDATE_RANGE:
544 case NLA_VALIDATE_RANGE_WARN_TOO_LONG:
545 case NLA_VALIDATE_MIN:
546 case NLA_VALIDATE_MAX:
547 err = nla_validate_int_range(pt, nla, extack, validate);
548 if (err)
549 return err;
550 break;
551 case NLA_VALIDATE_MASK:
552 err = nla_validate_mask(pt, nla, extack);
553 if (err)
554 return err;
555 break;
556 case NLA_VALIDATE_FUNCTION:
557 if (pt->validate) {
558 err = pt->validate(nla, extack);
559 if (err)
560 return err;
561 }
562 break;
563 }
564
565 return 0;
566out_err:
567 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
568 "Attribute failed policy validation");
569 return err;
570}
571
572static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
573 const struct nla_policy *policy,
574 unsigned int validate,
575 struct netlink_ext_ack *extack,
576 struct nlattr **tb, unsigned int depth)
577{
578 const struct nlattr *nla;
579 int rem;
580
581 if (depth >= MAX_POLICY_RECURSION_DEPTH) {
582 NL_SET_ERR_MSG(extack,
583 "allowed policy recursion depth exceeded");
584 return -EINVAL;
585 }
586
587 if (tb)
588 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
589
590 nla_for_each_attr(nla, head, len, rem) {
591 u16 type = nla_type(nla);
592
593 if (type == 0 || type > maxtype) {
594 if (validate & NL_VALIDATE_MAXTYPE) {
595 NL_SET_ERR_MSG_ATTR(extack, nla,
596 "Unknown attribute type");
597 return -EINVAL;
598 }
599 continue;
600 }
601 type = array_index_nospec(type, maxtype + 1);
602 if (policy) {
603 int err = validate_nla(nla, maxtype, policy,
604 validate, extack, depth);
605
606 if (err < 0)
607 return err;
608 }
609
610 if (tb)
611 tb[type] = (struct nlattr *)nla;
612 }
613
614 if (unlikely(rem > 0)) {
615 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
616 rem, current->comm);
617 NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes");
618 if (validate & NL_VALIDATE_TRAILING)
619 return -EINVAL;
620 }
621
622 return 0;
623}
624
625/**
626 * __nla_validate - Validate a stream of attributes
627 * @head: head of attribute stream
628 * @len: length of attribute stream
629 * @maxtype: maximum attribute type to be expected
630 * @policy: validation policy
631 * @validate: validation strictness
632 * @extack: extended ACK report struct
633 *
634 * Validates all attributes in the specified attribute stream against the
635 * specified policy. Validation depends on the validate flags passed, see
636 * &enum netlink_validation for more details on that.
637 * See documentation of struct nla_policy for more details.
638 *
639 * Returns 0 on success or a negative error code.
640 */
641int __nla_validate(const struct nlattr *head, int len, int maxtype,
642 const struct nla_policy *policy, unsigned int validate,
643 struct netlink_ext_ack *extack)
644{
645 return __nla_validate_parse(head, len, maxtype, policy, validate,
646 extack, NULL, 0);
647}
648EXPORT_SYMBOL(__nla_validate);
649
650/**
651 * nla_policy_len - Determine the max. length of a policy
652 * @p: policy to use
653 * @n: number of policies
654 *
655 * Determines the max. length of the policy. It is currently used
656 * to allocated Netlink buffers roughly the size of the actual
657 * message.
658 *
659 * Returns 0 on success or a negative error code.
660 */
661int
662nla_policy_len(const struct nla_policy *p, int n)
663{
664 int i, len = 0;
665
666 for (i = 0; i < n; i++, p++) {
667 if (p->len)
668 len += nla_total_size(p->len);
669 else if (nla_attr_len[p->type])
670 len += nla_total_size(nla_attr_len[p->type]);
671 else if (nla_attr_minlen[p->type])
672 len += nla_total_size(nla_attr_minlen[p->type]);
673 }
674
675 return len;
676}
677EXPORT_SYMBOL(nla_policy_len);
678
679/**
680 * __nla_parse - Parse a stream of attributes into a tb buffer
681 * @tb: destination array with maxtype+1 elements
682 * @maxtype: maximum attribute type to be expected
683 * @head: head of attribute stream
684 * @len: length of attribute stream
685 * @policy: validation policy
686 * @validate: validation strictness
687 * @extack: extended ACK pointer
688 *
689 * Parses a stream of attributes and stores a pointer to each attribute in
690 * the tb array accessible via the attribute type.
691 * Validation is controlled by the @validate parameter.
692 *
693 * Returns 0 on success or a negative error code.
694 */
695int __nla_parse(struct nlattr **tb, int maxtype,
696 const struct nlattr *head, int len,
697 const struct nla_policy *policy, unsigned int validate,
698 struct netlink_ext_ack *extack)
699{
700 return __nla_validate_parse(head, len, maxtype, policy, validate,
701 extack, tb, 0);
702}
703EXPORT_SYMBOL(__nla_parse);
704
705/**
706 * nla_find - Find a specific attribute in a stream of attributes
707 * @head: head of attribute stream
708 * @len: length of attribute stream
709 * @attrtype: type of attribute to look for
710 *
711 * Returns the first attribute in the stream matching the specified type.
712 */
713struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
714{
715 const struct nlattr *nla;
716 int rem;
717
718 nla_for_each_attr(nla, head, len, rem)
719 if (nla_type(nla) == attrtype)
720 return (struct nlattr *)nla;
721
722 return NULL;
723}
724EXPORT_SYMBOL(nla_find);
725
726/**
727 * nla_strscpy - Copy string attribute payload into a sized buffer
728 * @dst: Where to copy the string to.
729 * @nla: Attribute to copy the string from.
730 * @dstsize: Size of destination buffer.
731 *
732 * Copies at most dstsize - 1 bytes into the destination buffer.
733 * Unlike strlcpy the destination buffer is always padded out.
734 *
735 * Return:
736 * * srclen - Returns @nla length (not including the trailing %NUL).
737 * * -E2BIG - If @dstsize is 0 or greater than U16_MAX or @nla length greater
738 * than @dstsize.
739 */
740ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize)
741{
742 size_t srclen = nla_len(nla);
743 char *src = nla_data(nla);
744 ssize_t ret;
745 size_t len;
746
747 if (dstsize == 0 || WARN_ON_ONCE(dstsize > U16_MAX))
748 return -E2BIG;
749
750 if (srclen > 0 && src[srclen - 1] == '\0')
751 srclen--;
752
753 if (srclen >= dstsize) {
754 len = dstsize - 1;
755 ret = -E2BIG;
756 } else {
757 len = srclen;
758 ret = len;
759 }
760
761 memcpy(dst, src, len);
762 /* Zero pad end of dst. */
763 memset(dst + len, 0, dstsize - len);
764
765 return ret;
766}
767EXPORT_SYMBOL(nla_strscpy);
768
769/**
770 * nla_strdup - Copy string attribute payload into a newly allocated buffer
771 * @nla: attribute to copy the string from
772 * @flags: the type of memory to allocate (see kmalloc).
773 *
774 * Returns a pointer to the allocated buffer or NULL on error.
775 */
776char *nla_strdup(const struct nlattr *nla, gfp_t flags)
777{
778 size_t srclen = nla_len(nla);
779 char *src = nla_data(nla), *dst;
780
781 if (srclen > 0 && src[srclen - 1] == '\0')
782 srclen--;
783
784 dst = kmalloc(srclen + 1, flags);
785 if (dst != NULL) {
786 memcpy(dst, src, srclen);
787 dst[srclen] = '\0';
788 }
789 return dst;
790}
791EXPORT_SYMBOL(nla_strdup);
792
793/**
794 * nla_memcpy - Copy a netlink attribute into another memory area
795 * @dest: where to copy to memcpy
796 * @src: netlink attribute to copy from
797 * @count: size of the destination area
798 *
799 * Note: The number of bytes copied is limited by the length of
800 * attribute's payload. memcpy
801 *
802 * Returns the number of bytes copied.
803 */
804int nla_memcpy(void *dest, const struct nlattr *src, int count)
805{
806 int minlen = min_t(int, count, nla_len(src));
807
808 memcpy(dest, nla_data(src), minlen);
809 if (count > minlen)
810 memset(dest + minlen, 0, count - minlen);
811
812 return minlen;
813}
814EXPORT_SYMBOL(nla_memcpy);
815
816/**
817 * nla_memcmp - Compare an attribute with sized memory area
818 * @nla: netlink attribute
819 * @data: memory area
820 * @size: size of memory area
821 */
822int nla_memcmp(const struct nlattr *nla, const void *data,
823 size_t size)
824{
825 int d = nla_len(nla) - size;
826
827 if (d == 0)
828 d = memcmp(nla_data(nla), data, size);
829
830 return d;
831}
832EXPORT_SYMBOL(nla_memcmp);
833
834/**
835 * nla_strcmp - Compare a string attribute against a string
836 * @nla: netlink string attribute
837 * @str: another string
838 */
839int nla_strcmp(const struct nlattr *nla, const char *str)
840{
841 int len = strlen(str);
842 char *buf = nla_data(nla);
843 int attrlen = nla_len(nla);
844 int d;
845
846 while (attrlen > 0 && buf[attrlen - 1] == '\0')
847 attrlen--;
848
849 d = attrlen - len;
850 if (d == 0)
851 d = memcmp(nla_data(nla), str, len);
852
853 return d;
854}
855EXPORT_SYMBOL(nla_strcmp);
856
857#ifdef CONFIG_NET
858/**
859 * __nla_reserve - reserve room for attribute on the skb
860 * @skb: socket buffer to reserve room on
861 * @attrtype: attribute type
862 * @attrlen: length of attribute payload
863 *
864 * Adds a netlink attribute header to a socket buffer and reserves
865 * room for the payload but does not copy it.
866 *
867 * The caller is responsible to ensure that the skb provides enough
868 * tailroom for the attribute header and payload.
869 */
870struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
871{
872 struct nlattr *nla;
873
874 nla = skb_put(skb, nla_total_size(attrlen));
875 nla->nla_type = attrtype;
876 nla->nla_len = nla_attr_size(attrlen);
877
878 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
879
880 return nla;
881}
882EXPORT_SYMBOL(__nla_reserve);
883
884/**
885 * __nla_reserve_64bit - reserve room for attribute on the skb and align it
886 * @skb: socket buffer to reserve room on
887 * @attrtype: attribute type
888 * @attrlen: length of attribute payload
889 * @padattr: attribute type for the padding
890 *
891 * Adds a netlink attribute header to a socket buffer and reserves
892 * room for the payload but does not copy it. It also ensure that this
893 * attribute will have a 64-bit aligned nla_data() area.
894 *
895 * The caller is responsible to ensure that the skb provides enough
896 * tailroom for the attribute header and payload.
897 */
898struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
899 int attrlen, int padattr)
900{
901 nla_align_64bit(skb, padattr);
902
903 return __nla_reserve(skb, attrtype, attrlen);
904}
905EXPORT_SYMBOL(__nla_reserve_64bit);
906
907/**
908 * __nla_reserve_nohdr - reserve room for attribute without header
909 * @skb: socket buffer to reserve room on
910 * @attrlen: length of attribute payload
911 *
912 * Reserves room for attribute payload without a header.
913 *
914 * The caller is responsible to ensure that the skb provides enough
915 * tailroom for the payload.
916 */
917void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
918{
919 return skb_put_zero(skb, NLA_ALIGN(attrlen));
920}
921EXPORT_SYMBOL(__nla_reserve_nohdr);
922
923/**
924 * nla_reserve - reserve room for attribute on the skb
925 * @skb: socket buffer to reserve room on
926 * @attrtype: attribute type
927 * @attrlen: length of attribute payload
928 *
929 * Adds a netlink attribute header to a socket buffer and reserves
930 * room for the payload but does not copy it.
931 *
932 * Returns NULL if the tailroom of the skb is insufficient to store
933 * the attribute header and payload.
934 */
935struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
936{
937 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
938 return NULL;
939
940 return __nla_reserve(skb, attrtype, attrlen);
941}
942EXPORT_SYMBOL(nla_reserve);
943
944/**
945 * nla_reserve_64bit - reserve room for attribute on the skb and align it
946 * @skb: socket buffer to reserve room on
947 * @attrtype: attribute type
948 * @attrlen: length of attribute payload
949 * @padattr: attribute type for the padding
950 *
951 * Adds a netlink attribute header to a socket buffer and reserves
952 * room for the payload but does not copy it. It also ensure that this
953 * attribute will have a 64-bit aligned nla_data() area.
954 *
955 * Returns NULL if the tailroom of the skb is insufficient to store
956 * the attribute header and payload.
957 */
958struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
959 int padattr)
960{
961 size_t len;
962
963 if (nla_need_padding_for_64bit(skb))
964 len = nla_total_size_64bit(attrlen);
965 else
966 len = nla_total_size(attrlen);
967 if (unlikely(skb_tailroom(skb) < len))
968 return NULL;
969
970 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
971}
972EXPORT_SYMBOL(nla_reserve_64bit);
973
974/**
975 * nla_reserve_nohdr - reserve room for attribute without header
976 * @skb: socket buffer to reserve room on
977 * @attrlen: length of attribute payload
978 *
979 * Reserves room for attribute payload without a header.
980 *
981 * Returns NULL if the tailroom of the skb is insufficient to store
982 * the attribute payload.
983 */
984void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
985{
986 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
987 return NULL;
988
989 return __nla_reserve_nohdr(skb, attrlen);
990}
991EXPORT_SYMBOL(nla_reserve_nohdr);
992
993/**
994 * __nla_put - Add a netlink attribute to a socket buffer
995 * @skb: socket buffer to add attribute to
996 * @attrtype: attribute type
997 * @attrlen: length of attribute payload
998 * @data: head of attribute payload
999 *
1000 * The caller is responsible to ensure that the skb provides enough
1001 * tailroom for the attribute header and payload.
1002 */
1003void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
1004 const void *data)
1005{
1006 struct nlattr *nla;
1007
1008 nla = __nla_reserve(skb, attrtype, attrlen);
1009 memcpy(nla_data(nla), data, attrlen);
1010}
1011EXPORT_SYMBOL(__nla_put);
1012
1013/**
1014 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
1015 * @skb: socket buffer to add attribute to
1016 * @attrtype: attribute type
1017 * @attrlen: length of attribute payload
1018 * @data: head of attribute payload
1019 * @padattr: attribute type for the padding
1020 *
1021 * The caller is responsible to ensure that the skb provides enough
1022 * tailroom for the attribute header and payload.
1023 */
1024void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
1025 const void *data, int padattr)
1026{
1027 struct nlattr *nla;
1028
1029 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
1030 memcpy(nla_data(nla), data, attrlen);
1031}
1032EXPORT_SYMBOL(__nla_put_64bit);
1033
1034/**
1035 * __nla_put_nohdr - Add a netlink attribute without header
1036 * @skb: socket buffer to add attribute to
1037 * @attrlen: length of attribute payload
1038 * @data: head of attribute payload
1039 *
1040 * The caller is responsible to ensure that the skb provides enough
1041 * tailroom for the attribute payload.
1042 */
1043void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
1044{
1045 void *start;
1046
1047 start = __nla_reserve_nohdr(skb, attrlen);
1048 memcpy(start, data, attrlen);
1049}
1050EXPORT_SYMBOL(__nla_put_nohdr);
1051
1052/**
1053 * nla_put - Add a netlink attribute to a socket buffer
1054 * @skb: socket buffer to add attribute to
1055 * @attrtype: attribute type
1056 * @attrlen: length of attribute payload
1057 * @data: head of attribute payload
1058 *
1059 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
1060 * the attribute header and payload.
1061 */
1062int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
1063{
1064 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
1065 return -EMSGSIZE;
1066
1067 __nla_put(skb, attrtype, attrlen, data);
1068 return 0;
1069}
1070EXPORT_SYMBOL(nla_put);
1071
1072/**
1073 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
1074 * @skb: socket buffer to add attribute to
1075 * @attrtype: attribute type
1076 * @attrlen: length of attribute payload
1077 * @data: head of attribute payload
1078 * @padattr: attribute type for the padding
1079 *
1080 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
1081 * the attribute header and payload.
1082 */
1083int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
1084 const void *data, int padattr)
1085{
1086 size_t len;
1087
1088 if (nla_need_padding_for_64bit(skb))
1089 len = nla_total_size_64bit(attrlen);
1090 else
1091 len = nla_total_size(attrlen);
1092 if (unlikely(skb_tailroom(skb) < len))
1093 return -EMSGSIZE;
1094
1095 __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
1096 return 0;
1097}
1098EXPORT_SYMBOL(nla_put_64bit);
1099
1100/**
1101 * nla_put_nohdr - Add a netlink attribute without header
1102 * @skb: socket buffer to add attribute to
1103 * @attrlen: length of attribute payload
1104 * @data: head of attribute payload
1105 *
1106 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
1107 * the attribute payload.
1108 */
1109int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
1110{
1111 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
1112 return -EMSGSIZE;
1113
1114 __nla_put_nohdr(skb, attrlen, data);
1115 return 0;
1116}
1117EXPORT_SYMBOL(nla_put_nohdr);
1118
1119/**
1120 * nla_append - Add a netlink attribute without header or padding
1121 * @skb: socket buffer to add attribute to
1122 * @attrlen: length of attribute payload
1123 * @data: head of attribute payload
1124 *
1125 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
1126 * the attribute payload.
1127 */
1128int nla_append(struct sk_buff *skb, int attrlen, const void *data)
1129{
1130 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
1131 return -EMSGSIZE;
1132
1133 skb_put_data(skb, data, attrlen);
1134 return 0;
1135}
1136EXPORT_SYMBOL(nla_append);
1137#endif