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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/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 */
23static 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
34static 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
55static 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
61static 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
84static 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
114void 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
162static 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
223void 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
267static 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
302static 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
326static 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
357static 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;
552out_err:
553 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
554 "Attribute failed policy validation");
555 return err;
556}
557
558static 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 */
626int __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}
633EXPORT_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 */
646int
647nla_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}
662EXPORT_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 */
680int __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}
688EXPORT_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 */
698struct 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}
709EXPORT_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 */
725ssize_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}
752EXPORT_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 */
761char *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}
776EXPORT_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 */
789int 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}
799EXPORT_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 */
807int 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}
817EXPORT_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 */
824int 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}
840EXPORT_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 */
855struct 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}
867EXPORT_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 */
883struct 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}
890EXPORT_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 */
902void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
903{
904 return skb_put_zero(skb, NLA_ALIGN(attrlen));
905}
906EXPORT_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 */
920struct 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}
927EXPORT_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 */
943struct 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}
957EXPORT_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 */
969void *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}
976EXPORT_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 */
988void __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}
996EXPORT_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 */
1009void __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}
1017EXPORT_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 */
1028void __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}
1035EXPORT_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 */
1047int 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}
1055EXPORT_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 */
1068int 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}
1083EXPORT_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 */
1094int 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}
1102EXPORT_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 */
1113int 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}
1121EXPORT_SYMBOL(nla_append);
1122#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