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 };
34
35 static 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
validate_nla_bitfield32(const struct nlattr * nla,const u32 * valid_flags_mask)48 static int validate_nla_bitfield32(const struct nlattr *nla,
49 const u32 *valid_flags_mask)
50 {
51 const struct nla_bitfield32 *bf = nla_data(nla);
52
53 if (!valid_flags_mask)
54 return -EINVAL;
55
56 /*disallow invalid bit selector */
57 if (bf->selector & ~*valid_flags_mask)
58 return -EINVAL;
59
60 /*disallow invalid bit values */
61 if (bf->value & ~*valid_flags_mask)
62 return -EINVAL;
63
64 /*disallow valid bit values that are not selected*/
65 if (bf->value & ~bf->selector)
66 return -EINVAL;
67
68 return 0;
69 }
70
nla_validate_array(const struct nlattr * head,int len,int maxtype,const struct nla_policy * policy,struct netlink_ext_ack * extack,unsigned int validate)71 static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
72 const struct nla_policy *policy,
73 struct netlink_ext_ack *extack,
74 unsigned int validate)
75 {
76 const struct nlattr *entry;
77 int rem;
78
79 nla_for_each_attr(entry, head, len, rem) {
80 int ret;
81
82 if (nla_len(entry) == 0)
83 continue;
84
85 if (nla_len(entry) < NLA_HDRLEN) {
86 NL_SET_ERR_MSG_ATTR(extack, entry,
87 "Array element too short");
88 return -ERANGE;
89 }
90
91 ret = __nla_validate(nla_data(entry), nla_len(entry),
92 maxtype, policy, validate, extack);
93 if (ret < 0)
94 return ret;
95 }
96
97 return 0;
98 }
99
nla_validate_int_range(const struct nla_policy * pt,const struct nlattr * nla,struct netlink_ext_ack * extack)100 static int nla_validate_int_range(const struct nla_policy *pt,
101 const struct nlattr *nla,
102 struct netlink_ext_ack *extack)
103 {
104 bool validate_min, validate_max;
105 s64 value;
106
107 validate_min = pt->validation_type == NLA_VALIDATE_RANGE ||
108 pt->validation_type == NLA_VALIDATE_MIN;
109 validate_max = pt->validation_type == NLA_VALIDATE_RANGE ||
110 pt->validation_type == NLA_VALIDATE_MAX;
111
112 switch (pt->type) {
113 case NLA_U8:
114 value = nla_get_u8(nla);
115 break;
116 case NLA_U16:
117 value = nla_get_u16(nla);
118 break;
119 case NLA_U32:
120 value = nla_get_u32(nla);
121 break;
122 case NLA_S8:
123 value = nla_get_s8(nla);
124 break;
125 case NLA_S16:
126 value = nla_get_s16(nla);
127 break;
128 case NLA_S32:
129 value = nla_get_s32(nla);
130 break;
131 case NLA_S64:
132 value = nla_get_s64(nla);
133 break;
134 case NLA_U64:
135 /* treat this one specially, since it may not fit into s64 */
136 if ((validate_min && nla_get_u64(nla) < pt->min) ||
137 (validate_max && nla_get_u64(nla) > pt->max)) {
138 NL_SET_ERR_MSG_ATTR(extack, nla,
139 "integer out of range");
140 return -ERANGE;
141 }
142 return 0;
143 default:
144 WARN_ON(1);
145 return -EINVAL;
146 }
147
148 if ((validate_min && value < pt->min) ||
149 (validate_max && value > pt->max)) {
150 NL_SET_ERR_MSG_ATTR(extack, nla,
151 "integer out of range");
152 return -ERANGE;
153 }
154
155 return 0;
156 }
157
validate_nla(const struct nlattr * nla,int maxtype,const struct nla_policy * policy,unsigned int validate,struct netlink_ext_ack * extack)158 static int validate_nla(const struct nlattr *nla, int maxtype,
159 const struct nla_policy *policy, unsigned int validate,
160 struct netlink_ext_ack *extack)
161 {
162 u16 strict_start_type = policy[0].strict_start_type;
163 const struct nla_policy *pt;
164 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
165 int err = -ERANGE;
166
167 if (strict_start_type && type >= strict_start_type)
168 validate |= NL_VALIDATE_STRICT;
169
170 if (type <= 0 || type > maxtype)
171 return 0;
172
173 type = array_index_nospec(type, maxtype + 1);
174 pt = &policy[type];
175
176 BUG_ON(pt->type > NLA_TYPE_MAX);
177
178 if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) ||
179 (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
180 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
181 current->comm, type);
182 if (validate & NL_VALIDATE_STRICT_ATTRS) {
183 NL_SET_ERR_MSG_ATTR(extack, nla,
184 "invalid attribute length");
185 return -EINVAL;
186 }
187 }
188
189 if (validate & NL_VALIDATE_NESTED) {
190 if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&
191 !(nla->nla_type & NLA_F_NESTED)) {
192 NL_SET_ERR_MSG_ATTR(extack, nla,
193 "NLA_F_NESTED is missing");
194 return -EINVAL;
195 }
196 if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&
197 pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {
198 NL_SET_ERR_MSG_ATTR(extack, nla,
199 "NLA_F_NESTED not expected");
200 return -EINVAL;
201 }
202 }
203
204 switch (pt->type) {
205 case NLA_EXACT_LEN:
206 if (attrlen != pt->len)
207 goto out_err;
208 break;
209
210 case NLA_REJECT:
211 if (extack && pt->validation_data) {
212 NL_SET_BAD_ATTR(extack, nla);
213 extack->_msg = pt->validation_data;
214 return -EINVAL;
215 }
216 err = -EINVAL;
217 goto out_err;
218
219 case NLA_FLAG:
220 if (attrlen > 0)
221 goto out_err;
222 break;
223
224 case NLA_BITFIELD32:
225 if (attrlen != sizeof(struct nla_bitfield32))
226 goto out_err;
227
228 err = validate_nla_bitfield32(nla, pt->validation_data);
229 if (err)
230 goto out_err;
231 break;
232
233 case NLA_NUL_STRING:
234 if (pt->len)
235 minlen = min_t(int, attrlen, pt->len + 1);
236 else
237 minlen = attrlen;
238
239 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
240 err = -EINVAL;
241 goto out_err;
242 }
243 /* fall through */
244
245 case NLA_STRING:
246 if (attrlen < 1)
247 goto out_err;
248
249 if (pt->len) {
250 char *buf = nla_data(nla);
251
252 if (buf[attrlen - 1] == '\0')
253 attrlen--;
254
255 if (attrlen > pt->len)
256 goto out_err;
257 }
258 break;
259
260 case NLA_BINARY:
261 if (pt->len && attrlen > pt->len)
262 goto out_err;
263 break;
264
265 case NLA_NESTED:
266 /* a nested attributes is allowed to be empty; if its not,
267 * it must have a size of at least NLA_HDRLEN.
268 */
269 if (attrlen == 0)
270 break;
271 if (attrlen < NLA_HDRLEN)
272 goto out_err;
273 if (pt->validation_data) {
274 err = __nla_validate(nla_data(nla), nla_len(nla), pt->len,
275 pt->validation_data, validate,
276 extack);
277 if (err < 0) {
278 /*
279 * return directly to preserve the inner
280 * error message/attribute pointer
281 */
282 return err;
283 }
284 }
285 break;
286 case NLA_NESTED_ARRAY:
287 /* a nested array attribute is allowed to be empty; if its not,
288 * it must have a size of at least NLA_HDRLEN.
289 */
290 if (attrlen == 0)
291 break;
292 if (attrlen < NLA_HDRLEN)
293 goto out_err;
294 if (pt->validation_data) {
295 int err;
296
297 err = nla_validate_array(nla_data(nla), nla_len(nla),
298 pt->len, pt->validation_data,
299 extack, validate);
300 if (err < 0) {
301 /*
302 * return directly to preserve the inner
303 * error message/attribute pointer
304 */
305 return err;
306 }
307 }
308 break;
309
310 case NLA_UNSPEC:
311 if (validate & NL_VALIDATE_UNSPEC) {
312 NL_SET_ERR_MSG_ATTR(extack, nla,
313 "Unsupported attribute");
314 return -EINVAL;
315 }
316 /* fall through */
317 case NLA_MIN_LEN:
318 if (attrlen < pt->len)
319 goto out_err;
320 break;
321
322 default:
323 if (pt->len)
324 minlen = pt->len;
325 else
326 minlen = nla_attr_minlen[pt->type];
327
328 if (attrlen < minlen)
329 goto out_err;
330 }
331
332 /* further validation */
333 switch (pt->validation_type) {
334 case NLA_VALIDATE_NONE:
335 /* nothing to do */
336 break;
337 case NLA_VALIDATE_RANGE:
338 case NLA_VALIDATE_MIN:
339 case NLA_VALIDATE_MAX:
340 err = nla_validate_int_range(pt, nla, extack);
341 if (err)
342 return err;
343 break;
344 case NLA_VALIDATE_FUNCTION:
345 if (pt->validate) {
346 err = pt->validate(nla, extack);
347 if (err)
348 return err;
349 }
350 break;
351 }
352
353 return 0;
354 out_err:
355 NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation");
356 return err;
357 }
358
__nla_validate_parse(const struct nlattr * head,int len,int maxtype,const struct nla_policy * policy,unsigned int validate,struct netlink_ext_ack * extack,struct nlattr ** tb)359 static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
360 const struct nla_policy *policy,
361 unsigned int validate,
362 struct netlink_ext_ack *extack,
363 struct nlattr **tb)
364 {
365 const struct nlattr *nla;
366 int rem;
367
368 if (tb)
369 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
370
371 nla_for_each_attr(nla, head, len, rem) {
372 u16 type = nla_type(nla);
373
374 if (type == 0 || type > maxtype) {
375 if (validate & NL_VALIDATE_MAXTYPE) {
376 NL_SET_ERR_MSG_ATTR(extack, nla,
377 "Unknown attribute type");
378 return -EINVAL;
379 }
380 continue;
381 }
382 type = array_index_nospec(type, maxtype + 1);
383 if (policy) {
384 int err = validate_nla(nla, maxtype, policy,
385 validate, extack);
386
387 if (err < 0)
388 return err;
389 }
390
391 if (tb)
392 tb[type] = (struct nlattr *)nla;
393 }
394
395 if (unlikely(rem > 0)) {
396 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
397 rem, current->comm);
398 NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes");
399 if (validate & NL_VALIDATE_TRAILING)
400 return -EINVAL;
401 }
402
403 return 0;
404 }
405
406 /**
407 * __nla_validate - Validate a stream of attributes
408 * @head: head of attribute stream
409 * @len: length of attribute stream
410 * @maxtype: maximum attribute type to be expected
411 * @policy: validation policy
412 * @validate: validation strictness
413 * @extack: extended ACK report struct
414 *
415 * Validates all attributes in the specified attribute stream against the
416 * specified policy. Validation depends on the validate flags passed, see
417 * &enum netlink_validation for more details on that.
418 * See documenation of struct nla_policy for more details.
419 *
420 * Returns 0 on success or a negative error code.
421 */
__nla_validate(const struct nlattr * head,int len,int maxtype,const struct nla_policy * policy,unsigned int validate,struct netlink_ext_ack * extack)422 int __nla_validate(const struct nlattr *head, int len, int maxtype,
423 const struct nla_policy *policy, unsigned int validate,
424 struct netlink_ext_ack *extack)
425 {
426 return __nla_validate_parse(head, len, maxtype, policy, validate,
427 extack, NULL);
428 }
429 EXPORT_SYMBOL(__nla_validate);
430
431 /**
432 * nla_policy_len - Determin the max. length of a policy
433 * @policy: policy to use
434 * @n: number of policies
435 *
436 * Determines the max. length of the policy. It is currently used
437 * to allocated Netlink buffers roughly the size of the actual
438 * message.
439 *
440 * Returns 0 on success or a negative error code.
441 */
442 int
nla_policy_len(const struct nla_policy * p,int n)443 nla_policy_len(const struct nla_policy *p, int n)
444 {
445 int i, len = 0;
446
447 for (i = 0; i < n; i++, p++) {
448 if (p->len)
449 len += nla_total_size(p->len);
450 else if (nla_attr_len[p->type])
451 len += nla_total_size(nla_attr_len[p->type]);
452 else if (nla_attr_minlen[p->type])
453 len += nla_total_size(nla_attr_minlen[p->type]);
454 }
455
456 return len;
457 }
458 EXPORT_SYMBOL(nla_policy_len);
459
460 /**
461 * __nla_parse - Parse a stream of attributes into a tb buffer
462 * @tb: destination array with maxtype+1 elements
463 * @maxtype: maximum attribute type to be expected
464 * @head: head of attribute stream
465 * @len: length of attribute stream
466 * @policy: validation policy
467 * @validate: validation strictness
468 * @extack: extended ACK pointer
469 *
470 * Parses a stream of attributes and stores a pointer to each attribute in
471 * the tb array accessible via the attribute type.
472 * Validation is controlled by the @validate parameter.
473 *
474 * Returns 0 on success or a negative error code.
475 */
__nla_parse(struct nlattr ** tb,int maxtype,const struct nlattr * head,int len,const struct nla_policy * policy,unsigned int validate,struct netlink_ext_ack * extack)476 int __nla_parse(struct nlattr **tb, int maxtype,
477 const struct nlattr *head, int len,
478 const struct nla_policy *policy, unsigned int validate,
479 struct netlink_ext_ack *extack)
480 {
481 return __nla_validate_parse(head, len, maxtype, policy, validate,
482 extack, tb);
483 }
484 EXPORT_SYMBOL(__nla_parse);
485
486 /**
487 * nla_find - Find a specific attribute in a stream of attributes
488 * @head: head of attribute stream
489 * @len: length of attribute stream
490 * @attrtype: type of attribute to look for
491 *
492 * Returns the first attribute in the stream matching the specified type.
493 */
nla_find(const struct nlattr * head,int len,int attrtype)494 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
495 {
496 const struct nlattr *nla;
497 int rem;
498
499 nla_for_each_attr(nla, head, len, rem)
500 if (nla_type(nla) == attrtype)
501 return (struct nlattr *)nla;
502
503 return NULL;
504 }
505 EXPORT_SYMBOL(nla_find);
506
507 /**
508 * nla_strlcpy - Copy string attribute payload into a sized buffer
509 * @dst: where to copy the string to
510 * @nla: attribute to copy the string from
511 * @dstsize: size of destination buffer
512 *
513 * Copies at most dstsize - 1 bytes into the destination buffer.
514 * The result is always a valid NUL-terminated string. Unlike
515 * strlcpy the destination buffer is always padded out.
516 *
517 * Returns the length of the source buffer.
518 */
nla_strlcpy(char * dst,const struct nlattr * nla,size_t dstsize)519 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
520 {
521 size_t srclen = nla_len(nla);
522 char *src = nla_data(nla);
523
524 if (srclen > 0 && src[srclen - 1] == '\0')
525 srclen--;
526
527 if (dstsize > 0) {
528 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
529
530 memset(dst, 0, dstsize);
531 memcpy(dst, src, len);
532 }
533
534 return srclen;
535 }
536 EXPORT_SYMBOL(nla_strlcpy);
537
538 /**
539 * nla_strdup - Copy string attribute payload into a newly allocated buffer
540 * @nla: attribute to copy the string from
541 * @flags: the type of memory to allocate (see kmalloc).
542 *
543 * Returns a pointer to the allocated buffer or NULL on error.
544 */
nla_strdup(const struct nlattr * nla,gfp_t flags)545 char *nla_strdup(const struct nlattr *nla, gfp_t flags)
546 {
547 size_t srclen = nla_len(nla);
548 char *src = nla_data(nla), *dst;
549
550 if (srclen > 0 && src[srclen - 1] == '\0')
551 srclen--;
552
553 dst = kmalloc(srclen + 1, flags);
554 if (dst != NULL) {
555 memcpy(dst, src, srclen);
556 dst[srclen] = '\0';
557 }
558 return dst;
559 }
560 EXPORT_SYMBOL(nla_strdup);
561
562 /**
563 * nla_memcpy - Copy a netlink attribute into another memory area
564 * @dest: where to copy to memcpy
565 * @src: netlink attribute to copy from
566 * @count: size of the destination area
567 *
568 * Note: The number of bytes copied is limited by the length of
569 * attribute's payload. memcpy
570 *
571 * Returns the number of bytes copied.
572 */
nla_memcpy(void * dest,const struct nlattr * src,int count)573 int nla_memcpy(void *dest, const struct nlattr *src, int count)
574 {
575 int minlen = min_t(int, count, nla_len(src));
576
577 memcpy(dest, nla_data(src), minlen);
578 if (count > minlen)
579 memset(dest + minlen, 0, count - minlen);
580
581 return minlen;
582 }
583 EXPORT_SYMBOL(nla_memcpy);
584
585 /**
586 * nla_memcmp - Compare an attribute with sized memory area
587 * @nla: netlink attribute
588 * @data: memory area
589 * @size: size of memory area
590 */
nla_memcmp(const struct nlattr * nla,const void * data,size_t size)591 int nla_memcmp(const struct nlattr *nla, const void *data,
592 size_t size)
593 {
594 int d = nla_len(nla) - size;
595
596 if (d == 0)
597 d = memcmp(nla_data(nla), data, size);
598
599 return d;
600 }
601 EXPORT_SYMBOL(nla_memcmp);
602
603 /**
604 * nla_strcmp - Compare a string attribute against a string
605 * @nla: netlink string attribute
606 * @str: another string
607 */
nla_strcmp(const struct nlattr * nla,const char * str)608 int nla_strcmp(const struct nlattr *nla, const char *str)
609 {
610 int len = strlen(str);
611 char *buf = nla_data(nla);
612 int attrlen = nla_len(nla);
613 int d;
614
615 while (attrlen > 0 && buf[attrlen - 1] == '\0')
616 attrlen--;
617
618 d = attrlen - len;
619 if (d == 0)
620 d = memcmp(nla_data(nla), str, len);
621
622 return d;
623 }
624 EXPORT_SYMBOL(nla_strcmp);
625
626 #ifdef CONFIG_NET
627 /**
628 * __nla_reserve - reserve room for attribute on the skb
629 * @skb: socket buffer to reserve room on
630 * @attrtype: attribute type
631 * @attrlen: length of attribute payload
632 *
633 * Adds a netlink attribute header to a socket buffer and reserves
634 * room for the payload but does not copy it.
635 *
636 * The caller is responsible to ensure that the skb provides enough
637 * tailroom for the attribute header and payload.
638 */
__nla_reserve(struct sk_buff * skb,int attrtype,int attrlen)639 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
640 {
641 struct nlattr *nla;
642
643 nla = skb_put(skb, nla_total_size(attrlen));
644 nla->nla_type = attrtype;
645 nla->nla_len = nla_attr_size(attrlen);
646
647 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
648
649 return nla;
650 }
651 EXPORT_SYMBOL(__nla_reserve);
652
653 /**
654 * __nla_reserve_64bit - reserve room for attribute on the skb and align it
655 * @skb: socket buffer to reserve room on
656 * @attrtype: attribute type
657 * @attrlen: length of attribute payload
658 * @padattr: attribute type for the padding
659 *
660 * Adds a netlink attribute header to a socket buffer and reserves
661 * room for the payload but does not copy it. It also ensure that this
662 * attribute will have a 64-bit aligned nla_data() area.
663 *
664 * The caller is responsible to ensure that the skb provides enough
665 * tailroom for the attribute header and payload.
666 */
__nla_reserve_64bit(struct sk_buff * skb,int attrtype,int attrlen,int padattr)667 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
668 int attrlen, int padattr)
669 {
670 if (nla_need_padding_for_64bit(skb))
671 nla_align_64bit(skb, padattr);
672
673 return __nla_reserve(skb, attrtype, attrlen);
674 }
675 EXPORT_SYMBOL(__nla_reserve_64bit);
676
677 /**
678 * __nla_reserve_nohdr - reserve room for attribute without header
679 * @skb: socket buffer to reserve room on
680 * @attrlen: length of attribute payload
681 *
682 * Reserves room for attribute payload without a header.
683 *
684 * The caller is responsible to ensure that the skb provides enough
685 * tailroom for the payload.
686 */
__nla_reserve_nohdr(struct sk_buff * skb,int attrlen)687 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
688 {
689 return skb_put_zero(skb, NLA_ALIGN(attrlen));
690 }
691 EXPORT_SYMBOL(__nla_reserve_nohdr);
692
693 /**
694 * nla_reserve - reserve room for attribute on the skb
695 * @skb: socket buffer to reserve room on
696 * @attrtype: attribute type
697 * @attrlen: length of attribute payload
698 *
699 * Adds a netlink attribute header to a socket buffer and reserves
700 * room for the payload but does not copy it.
701 *
702 * Returns NULL if the tailroom of the skb is insufficient to store
703 * the attribute header and payload.
704 */
nla_reserve(struct sk_buff * skb,int attrtype,int attrlen)705 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
706 {
707 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
708 return NULL;
709
710 return __nla_reserve(skb, attrtype, attrlen);
711 }
712 EXPORT_SYMBOL(nla_reserve);
713
714 /**
715 * nla_reserve_64bit - reserve room for attribute on the skb and align it
716 * @skb: socket buffer to reserve room on
717 * @attrtype: attribute type
718 * @attrlen: length of attribute payload
719 * @padattr: attribute type for the padding
720 *
721 * Adds a netlink attribute header to a socket buffer and reserves
722 * room for the payload but does not copy it. It also ensure that this
723 * attribute will have a 64-bit aligned nla_data() area.
724 *
725 * Returns NULL if the tailroom of the skb is insufficient to store
726 * the attribute header and payload.
727 */
nla_reserve_64bit(struct sk_buff * skb,int attrtype,int attrlen,int padattr)728 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
729 int padattr)
730 {
731 size_t len;
732
733 if (nla_need_padding_for_64bit(skb))
734 len = nla_total_size_64bit(attrlen);
735 else
736 len = nla_total_size(attrlen);
737 if (unlikely(skb_tailroom(skb) < len))
738 return NULL;
739
740 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
741 }
742 EXPORT_SYMBOL(nla_reserve_64bit);
743
744 /**
745 * nla_reserve_nohdr - reserve room for attribute without header
746 * @skb: socket buffer to reserve room on
747 * @attrlen: length of attribute payload
748 *
749 * Reserves room for attribute payload without a header.
750 *
751 * Returns NULL if the tailroom of the skb is insufficient to store
752 * the attribute payload.
753 */
nla_reserve_nohdr(struct sk_buff * skb,int attrlen)754 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
755 {
756 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
757 return NULL;
758
759 return __nla_reserve_nohdr(skb, attrlen);
760 }
761 EXPORT_SYMBOL(nla_reserve_nohdr);
762
763 /**
764 * __nla_put - Add a netlink attribute to a socket buffer
765 * @skb: socket buffer to add attribute to
766 * @attrtype: attribute type
767 * @attrlen: length of attribute payload
768 * @data: head of attribute payload
769 *
770 * The caller is responsible to ensure that the skb provides enough
771 * tailroom for the attribute header and payload.
772 */
__nla_put(struct sk_buff * skb,int attrtype,int attrlen,const void * data)773 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
774 const void *data)
775 {
776 struct nlattr *nla;
777
778 nla = __nla_reserve(skb, attrtype, attrlen);
779 memcpy(nla_data(nla), data, attrlen);
780 }
781 EXPORT_SYMBOL(__nla_put);
782
783 /**
784 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
785 * @skb: socket buffer to add attribute to
786 * @attrtype: attribute type
787 * @attrlen: length of attribute payload
788 * @data: head of attribute payload
789 * @padattr: attribute type for the padding
790 *
791 * The caller is responsible to ensure that the skb provides enough
792 * tailroom for the attribute header and payload.
793 */
__nla_put_64bit(struct sk_buff * skb,int attrtype,int attrlen,const void * data,int padattr)794 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
795 const void *data, int padattr)
796 {
797 struct nlattr *nla;
798
799 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
800 memcpy(nla_data(nla), data, attrlen);
801 }
802 EXPORT_SYMBOL(__nla_put_64bit);
803
804 /**
805 * __nla_put_nohdr - Add a netlink attribute without header
806 * @skb: socket buffer to add attribute to
807 * @attrlen: length of attribute payload
808 * @data: head of attribute payload
809 *
810 * The caller is responsible to ensure that the skb provides enough
811 * tailroom for the attribute payload.
812 */
__nla_put_nohdr(struct sk_buff * skb,int attrlen,const void * data)813 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
814 {
815 void *start;
816
817 start = __nla_reserve_nohdr(skb, attrlen);
818 memcpy(start, data, attrlen);
819 }
820 EXPORT_SYMBOL(__nla_put_nohdr);
821
822 /**
823 * nla_put - Add a netlink attribute to a socket buffer
824 * @skb: socket buffer to add attribute to
825 * @attrtype: attribute type
826 * @attrlen: length of attribute payload
827 * @data: head of attribute payload
828 *
829 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
830 * the attribute header and payload.
831 */
nla_put(struct sk_buff * skb,int attrtype,int attrlen,const void * data)832 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
833 {
834 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
835 return -EMSGSIZE;
836
837 __nla_put(skb, attrtype, attrlen, data);
838 return 0;
839 }
840 EXPORT_SYMBOL(nla_put);
841
842 /**
843 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
844 * @skb: socket buffer to add attribute to
845 * @attrtype: attribute type
846 * @attrlen: length of attribute payload
847 * @data: head of attribute payload
848 * @padattr: attribute type for the padding
849 *
850 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
851 * the attribute header and payload.
852 */
nla_put_64bit(struct sk_buff * skb,int attrtype,int attrlen,const void * data,int padattr)853 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
854 const void *data, int padattr)
855 {
856 size_t len;
857
858 if (nla_need_padding_for_64bit(skb))
859 len = nla_total_size_64bit(attrlen);
860 else
861 len = nla_total_size(attrlen);
862 if (unlikely(skb_tailroom(skb) < len))
863 return -EMSGSIZE;
864
865 __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
866 return 0;
867 }
868 EXPORT_SYMBOL(nla_put_64bit);
869
870 /**
871 * nla_put_nohdr - Add a netlink attribute without header
872 * @skb: socket buffer to add attribute to
873 * @attrlen: length of attribute payload
874 * @data: head of attribute payload
875 *
876 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
877 * the attribute payload.
878 */
nla_put_nohdr(struct sk_buff * skb,int attrlen,const void * data)879 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
880 {
881 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
882 return -EMSGSIZE;
883
884 __nla_put_nohdr(skb, attrlen, data);
885 return 0;
886 }
887 EXPORT_SYMBOL(nla_put_nohdr);
888
889 /**
890 * nla_append - Add a netlink attribute without header or padding
891 * @skb: socket buffer to add attribute to
892 * @attrlen: length of attribute payload
893 * @data: head of attribute payload
894 *
895 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
896 * the attribute payload.
897 */
nla_append(struct sk_buff * skb,int attrlen,const void * data)898 int nla_append(struct sk_buff *skb, int attrlen, const void *data)
899 {
900 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
901 return -EMSGSIZE;
902
903 skb_put_data(skb, data, attrlen);
904 return 0;
905 }
906 EXPORT_SYMBOL(nla_append);
907 #endif
908