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 */
24 static 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
37 static 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
60 static 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
66 static 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
89 static 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
119 void 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
170 static 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
242 void 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
287 static 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
325 static 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
353 static 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
393 static 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;
598 out_err:
599 NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
600 "Attribute failed policy validation");
601 return err;
602 }
603
604 static 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 */
673 int __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 }
680 EXPORT_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 */
693 int
694 nla_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 }
709 EXPORT_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 */
727 int __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 }
735 EXPORT_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 */
745 struct 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 }
756 EXPORT_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 */
772 ssize_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 }
799 EXPORT_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 */
808 char *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 }
823 EXPORT_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 */
836 int 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 }
846 EXPORT_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 */
854 int 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 }
864 EXPORT_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 */
871 int 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 }
887 EXPORT_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 */
902 struct 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 }
914 EXPORT_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 */
930 struct 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 }
937 EXPORT_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 */
949 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
950 {
951 return skb_put_zero(skb, NLA_ALIGN(attrlen));
952 }
953 EXPORT_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 */
967 struct 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 }
974 EXPORT_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 */
990 struct 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 }
1004 EXPORT_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 */
1016 void *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 }
1023 EXPORT_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 */
1035 void __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 }
1043 EXPORT_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 */
1056 void __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 }
1064 EXPORT_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 */
1075 void __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 }
1082 EXPORT_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 */
1094 int 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 }
1102 EXPORT_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 */
1115 int 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 }
1130 EXPORT_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 */
1141 int 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 }
1149 EXPORT_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 */
1160 int 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 }
1168 EXPORT_SYMBOL(nla_append);
1169 #endif
1170
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