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1/*
2 * NETLINK Netlink attributes
3 *
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 */
7
8#include <linux/export.h>
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/jiffies.h>
12#include <linux/netdevice.h>
13#include <linux/skbuff.h>
14#include <linux/string.h>
15#include <linux/types.h>
16#include <net/netlink.h>
17
18static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
19 [NLA_U8] = sizeof(u8),
20 [NLA_U16] = sizeof(u16),
21 [NLA_U32] = sizeof(u32),
22 [NLA_U64] = sizeof(u64),
23 [NLA_MSECS] = sizeof(u64),
24 [NLA_NESTED] = NLA_HDRLEN,
25 [NLA_S8] = sizeof(s8),
26 [NLA_S16] = sizeof(s16),
27 [NLA_S32] = sizeof(s32),
28 [NLA_S64] = sizeof(s64),
29};
30
31static int validate_nla(const struct nlattr *nla, int maxtype,
32 const struct nla_policy *policy)
33{
34 const struct nla_policy *pt;
35 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
36
37 if (type <= 0 || type > maxtype)
38 return 0;
39
40 pt = &policy[type];
41
42 BUG_ON(pt->type > NLA_TYPE_MAX);
43
44 switch (pt->type) {
45 case NLA_FLAG:
46 if (attrlen > 0)
47 return -ERANGE;
48 break;
49
50 case NLA_NUL_STRING:
51 if (pt->len)
52 minlen = min_t(int, attrlen, pt->len + 1);
53 else
54 minlen = attrlen;
55
56 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
57 return -EINVAL;
58 /* fall through */
59
60 case NLA_STRING:
61 if (attrlen < 1)
62 return -ERANGE;
63
64 if (pt->len) {
65 char *buf = nla_data(nla);
66
67 if (buf[attrlen - 1] == '\0')
68 attrlen--;
69
70 if (attrlen > pt->len)
71 return -ERANGE;
72 }
73 break;
74
75 case NLA_BINARY:
76 if (pt->len && attrlen > pt->len)
77 return -ERANGE;
78 break;
79
80 case NLA_NESTED_COMPAT:
81 if (attrlen < pt->len)
82 return -ERANGE;
83 if (attrlen < NLA_ALIGN(pt->len))
84 break;
85 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
86 return -ERANGE;
87 nla = nla_data(nla) + NLA_ALIGN(pt->len);
88 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
89 return -ERANGE;
90 break;
91 case NLA_NESTED:
92 /* a nested attributes is allowed to be empty; if its not,
93 * it must have a size of at least NLA_HDRLEN.
94 */
95 if (attrlen == 0)
96 break;
97 default:
98 if (pt->len)
99 minlen = pt->len;
100 else if (pt->type != NLA_UNSPEC)
101 minlen = nla_attr_minlen[pt->type];
102
103 if (attrlen < minlen)
104 return -ERANGE;
105 }
106
107 return 0;
108}
109
110/**
111 * nla_validate - Validate a stream of attributes
112 * @head: head of attribute stream
113 * @len: length of attribute stream
114 * @maxtype: maximum attribute type to be expected
115 * @policy: validation policy
116 *
117 * Validates all attributes in the specified attribute stream against the
118 * specified policy. Attributes with a type exceeding maxtype will be
119 * ignored. See documenation of struct nla_policy for more details.
120 *
121 * Returns 0 on success or a negative error code.
122 */
123int nla_validate(const struct nlattr *head, int len, int maxtype,
124 const struct nla_policy *policy)
125{
126 const struct nlattr *nla;
127 int rem, err;
128
129 nla_for_each_attr(nla, head, len, rem) {
130 err = validate_nla(nla, maxtype, policy);
131 if (err < 0)
132 goto errout;
133 }
134
135 err = 0;
136errout:
137 return err;
138}
139
140/**
141 * nla_policy_len - Determin the max. length of a policy
142 * @policy: policy to use
143 * @n: number of policies
144 *
145 * Determines the max. length of the policy. It is currently used
146 * to allocated Netlink buffers roughly the size of the actual
147 * message.
148 *
149 * Returns 0 on success or a negative error code.
150 */
151int
152nla_policy_len(const struct nla_policy *p, int n)
153{
154 int i, len = 0;
155
156 for (i = 0; i < n; i++, p++) {
157 if (p->len)
158 len += nla_total_size(p->len);
159 else if (nla_attr_minlen[p->type])
160 len += nla_total_size(nla_attr_minlen[p->type]);
161 }
162
163 return len;
164}
165
166/**
167 * nla_parse - Parse a stream of attributes into a tb buffer
168 * @tb: destination array with maxtype+1 elements
169 * @maxtype: maximum attribute type to be expected
170 * @head: head of attribute stream
171 * @len: length of attribute stream
172 * @policy: validation policy
173 *
174 * Parses a stream of attributes and stores a pointer to each attribute in
175 * the tb array accessible via the attribute type. Attributes with a type
176 * exceeding maxtype will be silently ignored for backwards compatibility
177 * reasons. policy may be set to NULL if no validation is required.
178 *
179 * Returns 0 on success or a negative error code.
180 */
181int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
182 int len, const struct nla_policy *policy)
183{
184 const struct nlattr *nla;
185 int rem, err;
186
187 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
188
189 nla_for_each_attr(nla, head, len, rem) {
190 u16 type = nla_type(nla);
191
192 if (type > 0 && type <= maxtype) {
193 if (policy) {
194 err = validate_nla(nla, maxtype, policy);
195 if (err < 0)
196 goto errout;
197 }
198
199 tb[type] = (struct nlattr *)nla;
200 }
201 }
202
203 if (unlikely(rem > 0))
204 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
205 rem, current->comm);
206
207 err = 0;
208errout:
209 return err;
210}
211
212/**
213 * nla_find - Find a specific attribute in a stream of attributes
214 * @head: head of attribute stream
215 * @len: length of attribute stream
216 * @attrtype: type of attribute to look for
217 *
218 * Returns the first attribute in the stream matching the specified type.
219 */
220struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
221{
222 const struct nlattr *nla;
223 int rem;
224
225 nla_for_each_attr(nla, head, len, rem)
226 if (nla_type(nla) == attrtype)
227 return (struct nlattr *)nla;
228
229 return NULL;
230}
231
232/**
233 * nla_strlcpy - Copy string attribute payload into a sized buffer
234 * @dst: where to copy the string to
235 * @nla: attribute to copy the string from
236 * @dstsize: size of destination buffer
237 *
238 * Copies at most dstsize - 1 bytes into the destination buffer.
239 * The result is always a valid NUL-terminated string. Unlike
240 * strlcpy the destination buffer is always padded out.
241 *
242 * Returns the length of the source buffer.
243 */
244size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
245{
246 size_t srclen = nla_len(nla);
247 char *src = nla_data(nla);
248
249 if (srclen > 0 && src[srclen - 1] == '\0')
250 srclen--;
251
252 if (dstsize > 0) {
253 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
254
255 memset(dst, 0, dstsize);
256 memcpy(dst, src, len);
257 }
258
259 return srclen;
260}
261
262/**
263 * nla_memcpy - Copy a netlink attribute into another memory area
264 * @dest: where to copy to memcpy
265 * @src: netlink attribute to copy from
266 * @count: size of the destination area
267 *
268 * Note: The number of bytes copied is limited by the length of
269 * attribute's payload. memcpy
270 *
271 * Returns the number of bytes copied.
272 */
273int nla_memcpy(void *dest, const struct nlattr *src, int count)
274{
275 int minlen = min_t(int, count, nla_len(src));
276
277 memcpy(dest, nla_data(src), minlen);
278
279 return minlen;
280}
281
282/**
283 * nla_memcmp - Compare an attribute with sized memory area
284 * @nla: netlink attribute
285 * @data: memory area
286 * @size: size of memory area
287 */
288int nla_memcmp(const struct nlattr *nla, const void *data,
289 size_t size)
290{
291 int d = nla_len(nla) - size;
292
293 if (d == 0)
294 d = memcmp(nla_data(nla), data, size);
295
296 return d;
297}
298
299/**
300 * nla_strcmp - Compare a string attribute against a string
301 * @nla: netlink string attribute
302 * @str: another string
303 */
304int nla_strcmp(const struct nlattr *nla, const char *str)
305{
306 int len = strlen(str);
307 char *buf = nla_data(nla);
308 int attrlen = nla_len(nla);
309 int d;
310
311 if (attrlen > 0 && buf[attrlen - 1] == '\0')
312 attrlen--;
313
314 d = attrlen - len;
315 if (d == 0)
316 d = memcmp(nla_data(nla), str, len);
317
318 return d;
319}
320
321#ifdef CONFIG_NET
322/**
323 * __nla_reserve - reserve room for attribute on the skb
324 * @skb: socket buffer to reserve room on
325 * @attrtype: attribute type
326 * @attrlen: length of attribute payload
327 *
328 * Adds a netlink attribute header to a socket buffer and reserves
329 * room for the payload but does not copy it.
330 *
331 * The caller is responsible to ensure that the skb provides enough
332 * tailroom for the attribute header and payload.
333 */
334struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
335{
336 struct nlattr *nla;
337
338 nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
339 nla->nla_type = attrtype;
340 nla->nla_len = nla_attr_size(attrlen);
341
342 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
343
344 return nla;
345}
346EXPORT_SYMBOL(__nla_reserve);
347
348/**
349 * __nla_reserve_nohdr - reserve room for attribute without header
350 * @skb: socket buffer to reserve room on
351 * @attrlen: length of attribute payload
352 *
353 * Reserves room for attribute payload without a header.
354 *
355 * The caller is responsible to ensure that the skb provides enough
356 * tailroom for the payload.
357 */
358void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
359{
360 void *start;
361
362 start = skb_put(skb, NLA_ALIGN(attrlen));
363 memset(start, 0, NLA_ALIGN(attrlen));
364
365 return start;
366}
367EXPORT_SYMBOL(__nla_reserve_nohdr);
368
369/**
370 * nla_reserve - reserve room for attribute on the skb
371 * @skb: socket buffer to reserve room on
372 * @attrtype: attribute type
373 * @attrlen: length of attribute payload
374 *
375 * Adds a netlink attribute header to a socket buffer and reserves
376 * room for the payload but does not copy it.
377 *
378 * Returns NULL if the tailroom of the skb is insufficient to store
379 * the attribute header and payload.
380 */
381struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
382{
383 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
384 return NULL;
385
386 return __nla_reserve(skb, attrtype, attrlen);
387}
388EXPORT_SYMBOL(nla_reserve);
389
390/**
391 * nla_reserve_nohdr - reserve room for attribute without header
392 * @skb: socket buffer to reserve room on
393 * @attrlen: length of attribute payload
394 *
395 * Reserves room for attribute payload without a header.
396 *
397 * Returns NULL if the tailroom of the skb is insufficient to store
398 * the attribute payload.
399 */
400void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
401{
402 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
403 return NULL;
404
405 return __nla_reserve_nohdr(skb, attrlen);
406}
407EXPORT_SYMBOL(nla_reserve_nohdr);
408
409/**
410 * __nla_put - Add a netlink attribute to a socket buffer
411 * @skb: socket buffer to add attribute to
412 * @attrtype: attribute type
413 * @attrlen: length of attribute payload
414 * @data: head of attribute payload
415 *
416 * The caller is responsible to ensure that the skb provides enough
417 * tailroom for the attribute header and payload.
418 */
419void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
420 const void *data)
421{
422 struct nlattr *nla;
423
424 nla = __nla_reserve(skb, attrtype, attrlen);
425 memcpy(nla_data(nla), data, attrlen);
426}
427EXPORT_SYMBOL(__nla_put);
428
429/**
430 * __nla_put_nohdr - Add a netlink attribute without header
431 * @skb: socket buffer to add attribute to
432 * @attrlen: length of attribute payload
433 * @data: head of attribute payload
434 *
435 * The caller is responsible to ensure that the skb provides enough
436 * tailroom for the attribute payload.
437 */
438void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
439{
440 void *start;
441
442 start = __nla_reserve_nohdr(skb, attrlen);
443 memcpy(start, data, attrlen);
444}
445EXPORT_SYMBOL(__nla_put_nohdr);
446
447/**
448 * nla_put - Add a netlink attribute to a socket buffer
449 * @skb: socket buffer to add attribute to
450 * @attrtype: attribute type
451 * @attrlen: length of attribute payload
452 * @data: head of attribute payload
453 *
454 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
455 * the attribute header and payload.
456 */
457int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
458{
459 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
460 return -EMSGSIZE;
461
462 __nla_put(skb, attrtype, attrlen, data);
463 return 0;
464}
465EXPORT_SYMBOL(nla_put);
466
467/**
468 * nla_put_nohdr - Add a netlink attribute without header
469 * @skb: socket buffer to add attribute to
470 * @attrlen: length of attribute payload
471 * @data: head of attribute payload
472 *
473 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
474 * the attribute payload.
475 */
476int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
477{
478 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
479 return -EMSGSIZE;
480
481 __nla_put_nohdr(skb, attrlen, data);
482 return 0;
483}
484EXPORT_SYMBOL(nla_put_nohdr);
485
486/**
487 * nla_append - Add a netlink attribute without header or padding
488 * @skb: socket buffer to add attribute to
489 * @attrlen: length of attribute payload
490 * @data: head of attribute payload
491 *
492 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
493 * the attribute payload.
494 */
495int nla_append(struct sk_buff *skb, int attrlen, const void *data)
496{
497 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
498 return -EMSGSIZE;
499
500 memcpy(skb_put(skb, attrlen), data, attrlen);
501 return 0;
502}
503EXPORT_SYMBOL(nla_append);
504#endif
505
506EXPORT_SYMBOL(nla_validate);
507EXPORT_SYMBOL(nla_policy_len);
508EXPORT_SYMBOL(nla_parse);
509EXPORT_SYMBOL(nla_find);
510EXPORT_SYMBOL(nla_strlcpy);
511EXPORT_SYMBOL(nla_memcpy);
512EXPORT_SYMBOL(nla_memcmp);
513EXPORT_SYMBOL(nla_strcmp);
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
47static int validate_nla_bitfield32(const struct nlattr *nla,
48 const u32 *valid_flags_mask)
49{
50 const struct nla_bitfield32 *bf = nla_data(nla);
51
52 if (!valid_flags_mask)
53 return -EINVAL;
54
55 /*disallow invalid bit selector */
56 if (bf->selector & ~*valid_flags_mask)
57 return -EINVAL;
58
59 /*disallow invalid bit values */
60 if (bf->value & ~*valid_flags_mask)
61 return -EINVAL;
62
63 /*disallow valid bit values that are not selected*/
64 if (bf->value & ~bf->selector)
65 return -EINVAL;
66
67 return 0;
68}
69
70static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
71 const struct nla_policy *policy,
72 struct netlink_ext_ack *extack,
73 unsigned int validate)
74{
75 const struct nlattr *entry;
76 int rem;
77
78 nla_for_each_attr(entry, head, len, rem) {
79 int ret;
80
81 if (nla_len(entry) == 0)
82 continue;
83
84 if (nla_len(entry) < NLA_HDRLEN) {
85 NL_SET_ERR_MSG_ATTR(extack, entry,
86 "Array element too short");
87 return -ERANGE;
88 }
89
90 ret = __nla_validate(nla_data(entry), nla_len(entry),
91 maxtype, policy, validate, extack);
92 if (ret < 0)
93 return ret;
94 }
95
96 return 0;
97}
98
99static int nla_validate_int_range(const struct nla_policy *pt,
100 const struct nlattr *nla,
101 struct netlink_ext_ack *extack)
102{
103 bool validate_min, validate_max;
104 s64 value;
105
106 validate_min = pt->validation_type == NLA_VALIDATE_RANGE ||
107 pt->validation_type == NLA_VALIDATE_MIN;
108 validate_max = pt->validation_type == NLA_VALIDATE_RANGE ||
109 pt->validation_type == NLA_VALIDATE_MAX;
110
111 switch (pt->type) {
112 case NLA_U8:
113 value = nla_get_u8(nla);
114 break;
115 case NLA_U16:
116 value = nla_get_u16(nla);
117 break;
118 case NLA_U32:
119 value = nla_get_u32(nla);
120 break;
121 case NLA_S8:
122 value = nla_get_s8(nla);
123 break;
124 case NLA_S16:
125 value = nla_get_s16(nla);
126 break;
127 case NLA_S32:
128 value = nla_get_s32(nla);
129 break;
130 case NLA_S64:
131 value = nla_get_s64(nla);
132 break;
133 case NLA_U64:
134 /* treat this one specially, since it may not fit into s64 */
135 if ((validate_min && nla_get_u64(nla) < pt->min) ||
136 (validate_max && nla_get_u64(nla) > pt->max)) {
137 NL_SET_ERR_MSG_ATTR(extack, nla,
138 "integer out of range");
139 return -ERANGE;
140 }
141 return 0;
142 default:
143 WARN_ON(1);
144 return -EINVAL;
145 }
146
147 if ((validate_min && value < pt->min) ||
148 (validate_max && value > pt->max)) {
149 NL_SET_ERR_MSG_ATTR(extack, nla,
150 "integer out of range");
151 return -ERANGE;
152 }
153
154 return 0;
155}
156
157static int validate_nla(const struct nlattr *nla, int maxtype,
158 const struct nla_policy *policy, unsigned int validate,
159 struct netlink_ext_ack *extack)
160{
161 u16 strict_start_type = policy[0].strict_start_type;
162 const struct nla_policy *pt;
163 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
164 int err = -ERANGE;
165
166 if (strict_start_type && type >= strict_start_type)
167 validate |= NL_VALIDATE_STRICT;
168
169 if (type <= 0 || type > maxtype)
170 return 0;
171
172 pt = &policy[type];
173
174 BUG_ON(pt->type > NLA_TYPE_MAX);
175
176 if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) ||
177 (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
178 pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
179 current->comm, type);
180 if (validate & NL_VALIDATE_STRICT_ATTRS) {
181 NL_SET_ERR_MSG_ATTR(extack, nla,
182 "invalid attribute length");
183 return -EINVAL;
184 }
185 }
186
187 if (validate & NL_VALIDATE_NESTED) {
188 if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&
189 !(nla->nla_type & NLA_F_NESTED)) {
190 NL_SET_ERR_MSG_ATTR(extack, nla,
191 "NLA_F_NESTED is missing");
192 return -EINVAL;
193 }
194 if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&
195 pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {
196 NL_SET_ERR_MSG_ATTR(extack, nla,
197 "NLA_F_NESTED not expected");
198 return -EINVAL;
199 }
200 }
201
202 switch (pt->type) {
203 case NLA_EXACT_LEN:
204 if (attrlen != pt->len)
205 goto out_err;
206 break;
207
208 case NLA_REJECT:
209 if (extack && pt->validation_data) {
210 NL_SET_BAD_ATTR(extack, nla);
211 extack->_msg = pt->validation_data;
212 return -EINVAL;
213 }
214 err = -EINVAL;
215 goto out_err;
216
217 case NLA_FLAG:
218 if (attrlen > 0)
219 goto out_err;
220 break;
221
222 case NLA_BITFIELD32:
223 if (attrlen != sizeof(struct nla_bitfield32))
224 goto out_err;
225
226 err = validate_nla_bitfield32(nla, pt->validation_data);
227 if (err)
228 goto out_err;
229 break;
230
231 case NLA_NUL_STRING:
232 if (pt->len)
233 minlen = min_t(int, attrlen, pt->len + 1);
234 else
235 minlen = attrlen;
236
237 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
238 err = -EINVAL;
239 goto out_err;
240 }
241 /* fall through */
242
243 case NLA_STRING:
244 if (attrlen < 1)
245 goto out_err;
246
247 if (pt->len) {
248 char *buf = nla_data(nla);
249
250 if (buf[attrlen - 1] == '\0')
251 attrlen--;
252
253 if (attrlen > pt->len)
254 goto out_err;
255 }
256 break;
257
258 case NLA_BINARY:
259 if (pt->len && attrlen > pt->len)
260 goto out_err;
261 break;
262
263 case NLA_NESTED:
264 /* a nested attributes is allowed to be empty; if its not,
265 * it must have a size of at least NLA_HDRLEN.
266 */
267 if (attrlen == 0)
268 break;
269 if (attrlen < NLA_HDRLEN)
270 goto out_err;
271 if (pt->validation_data) {
272 err = __nla_validate(nla_data(nla), nla_len(nla), pt->len,
273 pt->validation_data, validate,
274 extack);
275 if (err < 0) {
276 /*
277 * return directly to preserve the inner
278 * error message/attribute pointer
279 */
280 return err;
281 }
282 }
283 break;
284 case NLA_NESTED_ARRAY:
285 /* a nested array attribute is allowed to be empty; if its not,
286 * it must have a size of at least NLA_HDRLEN.
287 */
288 if (attrlen == 0)
289 break;
290 if (attrlen < NLA_HDRLEN)
291 goto out_err;
292 if (pt->validation_data) {
293 int err;
294
295 err = nla_validate_array(nla_data(nla), nla_len(nla),
296 pt->len, pt->validation_data,
297 extack, validate);
298 if (err < 0) {
299 /*
300 * return directly to preserve the inner
301 * error message/attribute pointer
302 */
303 return err;
304 }
305 }
306 break;
307
308 case NLA_UNSPEC:
309 if (validate & NL_VALIDATE_UNSPEC) {
310 NL_SET_ERR_MSG_ATTR(extack, nla,
311 "Unsupported attribute");
312 return -EINVAL;
313 }
314 /* fall through */
315 case NLA_MIN_LEN:
316 if (attrlen < pt->len)
317 goto out_err;
318 break;
319
320 default:
321 if (pt->len)
322 minlen = pt->len;
323 else
324 minlen = nla_attr_minlen[pt->type];
325
326 if (attrlen < minlen)
327 goto out_err;
328 }
329
330 /* further validation */
331 switch (pt->validation_type) {
332 case NLA_VALIDATE_NONE:
333 /* nothing to do */
334 break;
335 case NLA_VALIDATE_RANGE:
336 case NLA_VALIDATE_MIN:
337 case NLA_VALIDATE_MAX:
338 err = nla_validate_int_range(pt, nla, extack);
339 if (err)
340 return err;
341 break;
342 case NLA_VALIDATE_FUNCTION:
343 if (pt->validate) {
344 err = pt->validate(nla, extack);
345 if (err)
346 return err;
347 }
348 break;
349 }
350
351 return 0;
352out_err:
353 NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation");
354 return err;
355}
356
357static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
358 const struct nla_policy *policy,
359 unsigned int validate,
360 struct netlink_ext_ack *extack,
361 struct nlattr **tb)
362{
363 const struct nlattr *nla;
364 int rem;
365
366 if (tb)
367 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
368
369 nla_for_each_attr(nla, head, len, rem) {
370 u16 type = nla_type(nla);
371
372 if (type == 0 || type > maxtype) {
373 if (validate & NL_VALIDATE_MAXTYPE) {
374 NL_SET_ERR_MSG_ATTR(extack, nla,
375 "Unknown attribute type");
376 return -EINVAL;
377 }
378 continue;
379 }
380 if (policy) {
381 int err = validate_nla(nla, maxtype, policy,
382 validate, extack);
383
384 if (err < 0)
385 return err;
386 }
387
388 if (tb)
389 tb[type] = (struct nlattr *)nla;
390 }
391
392 if (unlikely(rem > 0)) {
393 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
394 rem, current->comm);
395 NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes");
396 if (validate & NL_VALIDATE_TRAILING)
397 return -EINVAL;
398 }
399
400 return 0;
401}
402
403/**
404 * __nla_validate - Validate a stream of attributes
405 * @head: head of attribute stream
406 * @len: length of attribute stream
407 * @maxtype: maximum attribute type to be expected
408 * @policy: validation policy
409 * @validate: validation strictness
410 * @extack: extended ACK report struct
411 *
412 * Validates all attributes in the specified attribute stream against the
413 * specified policy. Validation depends on the validate flags passed, see
414 * &enum netlink_validation for more details on that.
415 * See documenation of struct nla_policy for more details.
416 *
417 * Returns 0 on success or a negative error code.
418 */
419int __nla_validate(const struct nlattr *head, int len, int maxtype,
420 const struct nla_policy *policy, unsigned int validate,
421 struct netlink_ext_ack *extack)
422{
423 return __nla_validate_parse(head, len, maxtype, policy, validate,
424 extack, NULL);
425}
426EXPORT_SYMBOL(__nla_validate);
427
428/**
429 * nla_policy_len - Determin the max. length of a policy
430 * @policy: policy to use
431 * @n: number of policies
432 *
433 * Determines the max. length of the policy. It is currently used
434 * to allocated Netlink buffers roughly the size of the actual
435 * message.
436 *
437 * Returns 0 on success or a negative error code.
438 */
439int
440nla_policy_len(const struct nla_policy *p, int n)
441{
442 int i, len = 0;
443
444 for (i = 0; i < n; i++, p++) {
445 if (p->len)
446 len += nla_total_size(p->len);
447 else if (nla_attr_len[p->type])
448 len += nla_total_size(nla_attr_len[p->type]);
449 else if (nla_attr_minlen[p->type])
450 len += nla_total_size(nla_attr_minlen[p->type]);
451 }
452
453 return len;
454}
455EXPORT_SYMBOL(nla_policy_len);
456
457/**
458 * __nla_parse - Parse a stream of attributes into a tb buffer
459 * @tb: destination array with maxtype+1 elements
460 * @maxtype: maximum attribute type to be expected
461 * @head: head of attribute stream
462 * @len: length of attribute stream
463 * @policy: validation policy
464 * @validate: validation strictness
465 * @extack: extended ACK pointer
466 *
467 * Parses a stream of attributes and stores a pointer to each attribute in
468 * the tb array accessible via the attribute type.
469 * Validation is controlled by the @validate parameter.
470 *
471 * Returns 0 on success or a negative error code.
472 */
473int __nla_parse(struct nlattr **tb, int maxtype,
474 const struct nlattr *head, int len,
475 const struct nla_policy *policy, unsigned int validate,
476 struct netlink_ext_ack *extack)
477{
478 return __nla_validate_parse(head, len, maxtype, policy, validate,
479 extack, tb);
480}
481EXPORT_SYMBOL(__nla_parse);
482
483/**
484 * nla_find - Find a specific attribute in a stream of attributes
485 * @head: head of attribute stream
486 * @len: length of attribute stream
487 * @attrtype: type of attribute to look for
488 *
489 * Returns the first attribute in the stream matching the specified type.
490 */
491struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
492{
493 const struct nlattr *nla;
494 int rem;
495
496 nla_for_each_attr(nla, head, len, rem)
497 if (nla_type(nla) == attrtype)
498 return (struct nlattr *)nla;
499
500 return NULL;
501}
502EXPORT_SYMBOL(nla_find);
503
504/**
505 * nla_strlcpy - Copy string attribute payload into a sized buffer
506 * @dst: where to copy the string to
507 * @nla: attribute to copy the string from
508 * @dstsize: size of destination buffer
509 *
510 * Copies at most dstsize - 1 bytes into the destination buffer.
511 * The result is always a valid NUL-terminated string. Unlike
512 * strlcpy the destination buffer is always padded out.
513 *
514 * Returns the length of the source buffer.
515 */
516size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
517{
518 size_t srclen = nla_len(nla);
519 char *src = nla_data(nla);
520
521 if (srclen > 0 && src[srclen - 1] == '\0')
522 srclen--;
523
524 if (dstsize > 0) {
525 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
526
527 memset(dst, 0, dstsize);
528 memcpy(dst, src, len);
529 }
530
531 return srclen;
532}
533EXPORT_SYMBOL(nla_strlcpy);
534
535/**
536 * nla_strdup - Copy string attribute payload into a newly allocated buffer
537 * @nla: attribute to copy the string from
538 * @flags: the type of memory to allocate (see kmalloc).
539 *
540 * Returns a pointer to the allocated buffer or NULL on error.
541 */
542char *nla_strdup(const struct nlattr *nla, gfp_t flags)
543{
544 size_t srclen = nla_len(nla);
545 char *src = nla_data(nla), *dst;
546
547 if (srclen > 0 && src[srclen - 1] == '\0')
548 srclen--;
549
550 dst = kmalloc(srclen + 1, flags);
551 if (dst != NULL) {
552 memcpy(dst, src, srclen);
553 dst[srclen] = '\0';
554 }
555 return dst;
556}
557EXPORT_SYMBOL(nla_strdup);
558
559/**
560 * nla_memcpy - Copy a netlink attribute into another memory area
561 * @dest: where to copy to memcpy
562 * @src: netlink attribute to copy from
563 * @count: size of the destination area
564 *
565 * Note: The number of bytes copied is limited by the length of
566 * attribute's payload. memcpy
567 *
568 * Returns the number of bytes copied.
569 */
570int nla_memcpy(void *dest, const struct nlattr *src, int count)
571{
572 int minlen = min_t(int, count, nla_len(src));
573
574 memcpy(dest, nla_data(src), minlen);
575 if (count > minlen)
576 memset(dest + minlen, 0, count - minlen);
577
578 return minlen;
579}
580EXPORT_SYMBOL(nla_memcpy);
581
582/**
583 * nla_memcmp - Compare an attribute with sized memory area
584 * @nla: netlink attribute
585 * @data: memory area
586 * @size: size of memory area
587 */
588int nla_memcmp(const struct nlattr *nla, const void *data,
589 size_t size)
590{
591 int d = nla_len(nla) - size;
592
593 if (d == 0)
594 d = memcmp(nla_data(nla), data, size);
595
596 return d;
597}
598EXPORT_SYMBOL(nla_memcmp);
599
600/**
601 * nla_strcmp - Compare a string attribute against a string
602 * @nla: netlink string attribute
603 * @str: another string
604 */
605int nla_strcmp(const struct nlattr *nla, const char *str)
606{
607 int len = strlen(str);
608 char *buf = nla_data(nla);
609 int attrlen = nla_len(nla);
610 int d;
611
612 if (attrlen > 0 && buf[attrlen - 1] == '\0')
613 attrlen--;
614
615 d = attrlen - len;
616 if (d == 0)
617 d = memcmp(nla_data(nla), str, len);
618
619 return d;
620}
621EXPORT_SYMBOL(nla_strcmp);
622
623#ifdef CONFIG_NET
624/**
625 * __nla_reserve - reserve room for attribute on the skb
626 * @skb: socket buffer to reserve room on
627 * @attrtype: attribute type
628 * @attrlen: length of attribute payload
629 *
630 * Adds a netlink attribute header to a socket buffer and reserves
631 * room for the payload but does not copy it.
632 *
633 * The caller is responsible to ensure that the skb provides enough
634 * tailroom for the attribute header and payload.
635 */
636struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
637{
638 struct nlattr *nla;
639
640 nla = skb_put(skb, nla_total_size(attrlen));
641 nla->nla_type = attrtype;
642 nla->nla_len = nla_attr_size(attrlen);
643
644 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
645
646 return nla;
647}
648EXPORT_SYMBOL(__nla_reserve);
649
650/**
651 * __nla_reserve_64bit - reserve room for attribute on the skb and align it
652 * @skb: socket buffer to reserve room on
653 * @attrtype: attribute type
654 * @attrlen: length of attribute payload
655 * @padattr: attribute type for the padding
656 *
657 * Adds a netlink attribute header to a socket buffer and reserves
658 * room for the payload but does not copy it. It also ensure that this
659 * attribute will have a 64-bit aligned nla_data() area.
660 *
661 * The caller is responsible to ensure that the skb provides enough
662 * tailroom for the attribute header and payload.
663 */
664struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
665 int attrlen, int padattr)
666{
667 if (nla_need_padding_for_64bit(skb))
668 nla_align_64bit(skb, padattr);
669
670 return __nla_reserve(skb, attrtype, attrlen);
671}
672EXPORT_SYMBOL(__nla_reserve_64bit);
673
674/**
675 * __nla_reserve_nohdr - reserve room for attribute without header
676 * @skb: socket buffer to reserve room on
677 * @attrlen: length of attribute payload
678 *
679 * Reserves room for attribute payload without a header.
680 *
681 * The caller is responsible to ensure that the skb provides enough
682 * tailroom for the payload.
683 */
684void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
685{
686 return skb_put_zero(skb, NLA_ALIGN(attrlen));
687}
688EXPORT_SYMBOL(__nla_reserve_nohdr);
689
690/**
691 * nla_reserve - reserve room for attribute on the skb
692 * @skb: socket buffer to reserve room on
693 * @attrtype: attribute type
694 * @attrlen: length of attribute payload
695 *
696 * Adds a netlink attribute header to a socket buffer and reserves
697 * room for the payload but does not copy it.
698 *
699 * Returns NULL if the tailroom of the skb is insufficient to store
700 * the attribute header and payload.
701 */
702struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
703{
704 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
705 return NULL;
706
707 return __nla_reserve(skb, attrtype, attrlen);
708}
709EXPORT_SYMBOL(nla_reserve);
710
711/**
712 * nla_reserve_64bit - reserve room for attribute on the skb and align it
713 * @skb: socket buffer to reserve room on
714 * @attrtype: attribute type
715 * @attrlen: length of attribute payload
716 * @padattr: attribute type for the padding
717 *
718 * Adds a netlink attribute header to a socket buffer and reserves
719 * room for the payload but does not copy it. It also ensure that this
720 * attribute will have a 64-bit aligned nla_data() area.
721 *
722 * Returns NULL if the tailroom of the skb is insufficient to store
723 * the attribute header and payload.
724 */
725struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
726 int padattr)
727{
728 size_t len;
729
730 if (nla_need_padding_for_64bit(skb))
731 len = nla_total_size_64bit(attrlen);
732 else
733 len = nla_total_size(attrlen);
734 if (unlikely(skb_tailroom(skb) < len))
735 return NULL;
736
737 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
738}
739EXPORT_SYMBOL(nla_reserve_64bit);
740
741/**
742 * nla_reserve_nohdr - reserve room for attribute without header
743 * @skb: socket buffer to reserve room on
744 * @attrlen: length of attribute payload
745 *
746 * Reserves room for attribute payload without a header.
747 *
748 * Returns NULL if the tailroom of the skb is insufficient to store
749 * the attribute payload.
750 */
751void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
752{
753 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
754 return NULL;
755
756 return __nla_reserve_nohdr(skb, attrlen);
757}
758EXPORT_SYMBOL(nla_reserve_nohdr);
759
760/**
761 * __nla_put - Add a netlink attribute to a socket buffer
762 * @skb: socket buffer to add attribute to
763 * @attrtype: attribute type
764 * @attrlen: length of attribute payload
765 * @data: head of attribute payload
766 *
767 * The caller is responsible to ensure that the skb provides enough
768 * tailroom for the attribute header and payload.
769 */
770void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
771 const void *data)
772{
773 struct nlattr *nla;
774
775 nla = __nla_reserve(skb, attrtype, attrlen);
776 memcpy(nla_data(nla), data, attrlen);
777}
778EXPORT_SYMBOL(__nla_put);
779
780/**
781 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
782 * @skb: socket buffer to add attribute to
783 * @attrtype: attribute type
784 * @attrlen: length of attribute payload
785 * @data: head of attribute payload
786 * @padattr: attribute type for the padding
787 *
788 * The caller is responsible to ensure that the skb provides enough
789 * tailroom for the attribute header and payload.
790 */
791void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
792 const void *data, int padattr)
793{
794 struct nlattr *nla;
795
796 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
797 memcpy(nla_data(nla), data, attrlen);
798}
799EXPORT_SYMBOL(__nla_put_64bit);
800
801/**
802 * __nla_put_nohdr - Add a netlink attribute without header
803 * @skb: socket buffer to add attribute to
804 * @attrlen: length of attribute payload
805 * @data: head of attribute payload
806 *
807 * The caller is responsible to ensure that the skb provides enough
808 * tailroom for the attribute payload.
809 */
810void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
811{
812 void *start;
813
814 start = __nla_reserve_nohdr(skb, attrlen);
815 memcpy(start, data, attrlen);
816}
817EXPORT_SYMBOL(__nla_put_nohdr);
818
819/**
820 * nla_put - Add a netlink attribute to a socket buffer
821 * @skb: socket buffer to add attribute to
822 * @attrtype: attribute type
823 * @attrlen: length of attribute payload
824 * @data: head of attribute payload
825 *
826 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
827 * the attribute header and payload.
828 */
829int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
830{
831 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
832 return -EMSGSIZE;
833
834 __nla_put(skb, attrtype, attrlen, data);
835 return 0;
836}
837EXPORT_SYMBOL(nla_put);
838
839/**
840 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
841 * @skb: socket buffer to add attribute to
842 * @attrtype: attribute type
843 * @attrlen: length of attribute payload
844 * @data: head of attribute payload
845 * @padattr: attribute type for the padding
846 *
847 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
848 * the attribute header and payload.
849 */
850int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
851 const void *data, int padattr)
852{
853 size_t len;
854
855 if (nla_need_padding_for_64bit(skb))
856 len = nla_total_size_64bit(attrlen);
857 else
858 len = nla_total_size(attrlen);
859 if (unlikely(skb_tailroom(skb) < len))
860 return -EMSGSIZE;
861
862 __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
863 return 0;
864}
865EXPORT_SYMBOL(nla_put_64bit);
866
867/**
868 * nla_put_nohdr - Add a netlink attribute without header
869 * @skb: socket buffer to add attribute to
870 * @attrlen: length of attribute payload
871 * @data: head of attribute payload
872 *
873 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
874 * the attribute payload.
875 */
876int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
877{
878 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
879 return -EMSGSIZE;
880
881 __nla_put_nohdr(skb, attrlen, data);
882 return 0;
883}
884EXPORT_SYMBOL(nla_put_nohdr);
885
886/**
887 * nla_append - Add a netlink attribute without header or padding
888 * @skb: socket buffer to add attribute to
889 * @attrlen: length of attribute payload
890 * @data: head of attribute payload
891 *
892 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
893 * the attribute payload.
894 */
895int nla_append(struct sk_buff *skb, int attrlen, const void *data)
896{
897 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
898 return -EMSGSIZE;
899
900 skb_put_data(skb, data, attrlen);
901 return 0;
902}
903EXPORT_SYMBOL(nla_append);
904#endif