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Commit | Line | Data |
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bfa83a9e TG |
1 | /* |
2 | * NETLINK Netlink attributes | |
3 | * | |
4 | * Authors: Thomas Graf <tgraf@suug.ch> | |
5 | * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> | |
6 | */ | |
7 | ||
bfa83a9e TG |
8 | #include <linux/module.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 | ||
18 | static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { | |
19 | [NLA_U8] = sizeof(u8), | |
20 | [NLA_U16] = sizeof(u16), | |
21 | [NLA_U32] = sizeof(u32), | |
22 | [NLA_U64] = sizeof(u64), | |
bfa83a9e TG |
23 | [NLA_NESTED] = NLA_HDRLEN, |
24 | }; | |
25 | ||
26 | static int validate_nla(struct nlattr *nla, int maxtype, | |
ef7c79ed | 27 | const struct nla_policy *policy) |
bfa83a9e | 28 | { |
ef7c79ed | 29 | const struct nla_policy *pt; |
8f4c1f9b | 30 | int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); |
bfa83a9e | 31 | |
8f4c1f9b | 32 | if (type <= 0 || type > maxtype) |
bfa83a9e TG |
33 | return 0; |
34 | ||
8f4c1f9b | 35 | pt = &policy[type]; |
bfa83a9e TG |
36 | |
37 | BUG_ON(pt->type > NLA_TYPE_MAX); | |
38 | ||
a5531a5d TG |
39 | switch (pt->type) { |
40 | case NLA_FLAG: | |
41 | if (attrlen > 0) | |
42 | return -ERANGE; | |
43 | break; | |
bfa83a9e | 44 | |
a5531a5d TG |
45 | case NLA_NUL_STRING: |
46 | if (pt->len) | |
47 | minlen = min_t(int, attrlen, pt->len + 1); | |
48 | else | |
49 | minlen = attrlen; | |
bfa83a9e | 50 | |
a5531a5d TG |
51 | if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) |
52 | return -EINVAL; | |
53 | /* fall through */ | |
54 | ||
55 | case NLA_STRING: | |
56 | if (attrlen < 1) | |
57 | return -ERANGE; | |
58 | ||
59 | if (pt->len) { | |
60 | char *buf = nla_data(nla); | |
61 | ||
62 | if (buf[attrlen - 1] == '\0') | |
63 | attrlen--; | |
64 | ||
65 | if (attrlen > pt->len) | |
66 | return -ERANGE; | |
67 | } | |
68 | break; | |
69 | ||
d30045a0 JB |
70 | case NLA_BINARY: |
71 | if (pt->len && attrlen > pt->len) | |
72 | return -ERANGE; | |
73 | break; | |
74 | ||
1092cb21 PM |
75 | case NLA_NESTED_COMPAT: |
76 | if (attrlen < pt->len) | |
77 | return -ERANGE; | |
78 | if (attrlen < NLA_ALIGN(pt->len)) | |
79 | break; | |
80 | if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN) | |
81 | return -ERANGE; | |
82 | nla = nla_data(nla) + NLA_ALIGN(pt->len); | |
83 | if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla)) | |
84 | return -ERANGE; | |
85 | break; | |
a5531a5d TG |
86 | default: |
87 | if (pt->len) | |
88 | minlen = pt->len; | |
89 | else if (pt->type != NLA_UNSPEC) | |
90 | minlen = nla_attr_minlen[pt->type]; | |
91 | ||
92 | if (attrlen < minlen) | |
93 | return -ERANGE; | |
94 | } | |
bfa83a9e TG |
95 | |
96 | return 0; | |
97 | } | |
98 | ||
99 | /** | |
100 | * nla_validate - Validate a stream of attributes | |
101 | * @head: head of attribute stream | |
102 | * @len: length of attribute stream | |
103 | * @maxtype: maximum attribute type to be expected | |
104 | * @policy: validation policy | |
105 | * | |
106 | * Validates all attributes in the specified attribute stream against the | |
107 | * specified policy. Attributes with a type exceeding maxtype will be | |
108 | * ignored. See documenation of struct nla_policy for more details. | |
109 | * | |
110 | * Returns 0 on success or a negative error code. | |
111 | */ | |
112 | int nla_validate(struct nlattr *head, int len, int maxtype, | |
ef7c79ed | 113 | const struct nla_policy *policy) |
bfa83a9e TG |
114 | { |
115 | struct nlattr *nla; | |
116 | int rem, err; | |
117 | ||
118 | nla_for_each_attr(nla, head, len, rem) { | |
119 | err = validate_nla(nla, maxtype, policy); | |
120 | if (err < 0) | |
121 | goto errout; | |
122 | } | |
123 | ||
124 | err = 0; | |
125 | errout: | |
126 | return err; | |
127 | } | |
128 | ||
129 | /** | |
130 | * nla_parse - Parse a stream of attributes into a tb buffer | |
131 | * @tb: destination array with maxtype+1 elements | |
132 | * @maxtype: maximum attribute type to be expected | |
133 | * @head: head of attribute stream | |
134 | * @len: length of attribute stream | |
135 | * | |
136 | * Parses a stream of attributes and stores a pointer to each attribute in | |
137 | * the tb array accessable via the attribute type. Attributes with a type | |
138 | * exceeding maxtype will be silently ignored for backwards compatibility | |
139 | * reasons. policy may be set to NULL if no validation is required. | |
140 | * | |
141 | * Returns 0 on success or a negative error code. | |
142 | */ | |
143 | int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, | |
ef7c79ed | 144 | const struct nla_policy *policy) |
bfa83a9e TG |
145 | { |
146 | struct nlattr *nla; | |
147 | int rem, err; | |
148 | ||
149 | memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); | |
150 | ||
151 | nla_for_each_attr(nla, head, len, rem) { | |
8f4c1f9b | 152 | u16 type = nla_type(nla); |
bfa83a9e TG |
153 | |
154 | if (type > 0 && type <= maxtype) { | |
155 | if (policy) { | |
156 | err = validate_nla(nla, maxtype, policy); | |
157 | if (err < 0) | |
158 | goto errout; | |
159 | } | |
160 | ||
161 | tb[type] = nla; | |
162 | } | |
163 | } | |
164 | ||
165 | if (unlikely(rem > 0)) | |
166 | printk(KERN_WARNING "netlink: %d bytes leftover after parsing " | |
167 | "attributes.\n", rem); | |
168 | ||
169 | err = 0; | |
170 | errout: | |
171 | return err; | |
172 | } | |
173 | ||
174 | /** | |
175 | * nla_find - Find a specific attribute in a stream of attributes | |
176 | * @head: head of attribute stream | |
177 | * @len: length of attribute stream | |
178 | * @attrtype: type of attribute to look for | |
179 | * | |
180 | * Returns the first attribute in the stream matching the specified type. | |
181 | */ | |
182 | struct nlattr *nla_find(struct nlattr *head, int len, int attrtype) | |
183 | { | |
184 | struct nlattr *nla; | |
185 | int rem; | |
186 | ||
187 | nla_for_each_attr(nla, head, len, rem) | |
8f4c1f9b | 188 | if (nla_type(nla) == attrtype) |
bfa83a9e TG |
189 | return nla; |
190 | ||
191 | return NULL; | |
192 | } | |
193 | ||
194 | /** | |
195 | * nla_strlcpy - Copy string attribute payload into a sized buffer | |
196 | * @dst: where to copy the string to | |
197 | * @src: attribute to copy the string from | |
198 | * @dstsize: size of destination buffer | |
199 | * | |
200 | * Copies at most dstsize - 1 bytes into the destination buffer. | |
201 | * The result is always a valid NUL-terminated string. Unlike | |
202 | * strlcpy the destination buffer is always padded out. | |
203 | * | |
204 | * Returns the length of the source buffer. | |
205 | */ | |
206 | size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize) | |
207 | { | |
208 | size_t srclen = nla_len(nla); | |
209 | char *src = nla_data(nla); | |
210 | ||
211 | if (srclen > 0 && src[srclen - 1] == '\0') | |
212 | srclen--; | |
213 | ||
214 | if (dstsize > 0) { | |
215 | size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; | |
216 | ||
217 | memset(dst, 0, dstsize); | |
218 | memcpy(dst, src, len); | |
219 | } | |
220 | ||
221 | return srclen; | |
222 | } | |
223 | ||
224 | /** | |
225 | * nla_memcpy - Copy a netlink attribute into another memory area | |
226 | * @dest: where to copy to memcpy | |
227 | * @src: netlink attribute to copy from | |
228 | * @count: size of the destination area | |
229 | * | |
230 | * Note: The number of bytes copied is limited by the length of | |
231 | * attribute's payload. memcpy | |
232 | * | |
233 | * Returns the number of bytes copied. | |
234 | */ | |
235 | int nla_memcpy(void *dest, struct nlattr *src, int count) | |
236 | { | |
237 | int minlen = min_t(int, count, nla_len(src)); | |
238 | ||
239 | memcpy(dest, nla_data(src), minlen); | |
240 | ||
241 | return minlen; | |
242 | } | |
243 | ||
244 | /** | |
245 | * nla_memcmp - Compare an attribute with sized memory area | |
246 | * @nla: netlink attribute | |
247 | * @data: memory area | |
248 | * @size: size of memory area | |
249 | */ | |
250 | int nla_memcmp(const struct nlattr *nla, const void *data, | |
251 | size_t size) | |
252 | { | |
253 | int d = nla_len(nla) - size; | |
254 | ||
255 | if (d == 0) | |
256 | d = memcmp(nla_data(nla), data, size); | |
257 | ||
258 | return d; | |
259 | } | |
260 | ||
261 | /** | |
262 | * nla_strcmp - Compare a string attribute against a string | |
263 | * @nla: netlink string attribute | |
264 | * @str: another string | |
265 | */ | |
266 | int nla_strcmp(const struct nlattr *nla, const char *str) | |
267 | { | |
268 | int len = strlen(str) + 1; | |
269 | int d = nla_len(nla) - len; | |
270 | ||
271 | if (d == 0) | |
272 | d = memcmp(nla_data(nla), str, len); | |
273 | ||
274 | return d; | |
275 | } | |
276 | ||
277 | /** | |
278 | * __nla_reserve - reserve room for attribute on the skb | |
279 | * @skb: socket buffer to reserve room on | |
280 | * @attrtype: attribute type | |
281 | * @attrlen: length of attribute payload | |
282 | * | |
283 | * Adds a netlink attribute header to a socket buffer and reserves | |
284 | * room for the payload but does not copy it. | |
285 | * | |
286 | * The caller is responsible to ensure that the skb provides enough | |
287 | * tailroom for the attribute header and payload. | |
288 | */ | |
289 | struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
290 | { | |
291 | struct nlattr *nla; | |
292 | ||
293 | nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen)); | |
294 | nla->nla_type = attrtype; | |
295 | nla->nla_len = nla_attr_size(attrlen); | |
296 | ||
297 | memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); | |
298 | ||
299 | return nla; | |
300 | } | |
301 | ||
fe4944e5 TG |
302 | /** |
303 | * __nla_reserve_nohdr - reserve room for attribute without header | |
304 | * @skb: socket buffer to reserve room on | |
305 | * @attrlen: length of attribute payload | |
306 | * | |
307 | * Reserves room for attribute payload without a header. | |
308 | * | |
309 | * The caller is responsible to ensure that the skb provides enough | |
310 | * tailroom for the payload. | |
311 | */ | |
312 | void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
313 | { | |
314 | void *start; | |
315 | ||
316 | start = skb_put(skb, NLA_ALIGN(attrlen)); | |
317 | memset(start, 0, NLA_ALIGN(attrlen)); | |
318 | ||
319 | return start; | |
320 | } | |
321 | ||
bfa83a9e TG |
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 | * Returns NULL if the tailroom of the skb is insufficient to store | |
332 | * the attribute header and payload. | |
333 | */ | |
334 | struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
335 | { | |
336 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
337 | return NULL; | |
338 | ||
339 | return __nla_reserve(skb, attrtype, attrlen); | |
340 | } | |
341 | ||
fe4944e5 TG |
342 | /** |
343 | * nla_reserve - reserve room for attribute without header | |
344 | * @skb: socket buffer to reserve room on | |
345 | * @len: length of attribute payload | |
346 | * | |
347 | * Reserves room for attribute payload without a header. | |
348 | * | |
349 | * Returns NULL if the tailroom of the skb is insufficient to store | |
350 | * the attribute payload. | |
351 | */ | |
352 | void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
353 | { | |
354 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
355 | return NULL; | |
356 | ||
357 | return __nla_reserve_nohdr(skb, attrlen); | |
358 | } | |
359 | ||
bfa83a9e TG |
360 | /** |
361 | * __nla_put - Add a netlink attribute to a socket buffer | |
362 | * @skb: socket buffer to add attribute to | |
363 | * @attrtype: attribute type | |
364 | * @attrlen: length of attribute payload | |
365 | * @data: head of attribute payload | |
366 | * | |
367 | * The caller is responsible to ensure that the skb provides enough | |
368 | * tailroom for the attribute header and payload. | |
369 | */ | |
370 | void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, | |
371 | const void *data) | |
372 | { | |
373 | struct nlattr *nla; | |
374 | ||
375 | nla = __nla_reserve(skb, attrtype, attrlen); | |
376 | memcpy(nla_data(nla), data, attrlen); | |
377 | } | |
378 | ||
fe4944e5 TG |
379 | /** |
380 | * __nla_put_nohdr - Add a netlink attribute without header | |
381 | * @skb: socket buffer to add attribute to | |
382 | * @attrlen: length of attribute payload | |
383 | * @data: head of attribute payload | |
384 | * | |
385 | * The caller is responsible to ensure that the skb provides enough | |
386 | * tailroom for the attribute payload. | |
387 | */ | |
388 | void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
389 | { | |
390 | void *start; | |
391 | ||
392 | start = __nla_reserve_nohdr(skb, attrlen); | |
393 | memcpy(start, data, attrlen); | |
394 | } | |
bfa83a9e TG |
395 | |
396 | /** | |
397 | * nla_put - Add a netlink attribute to a socket buffer | |
398 | * @skb: socket buffer to add attribute to | |
399 | * @attrtype: attribute type | |
400 | * @attrlen: length of attribute payload | |
401 | * @data: head of attribute payload | |
402 | * | |
403 | * Returns -1 if the tailroom of the skb is insufficient to store | |
404 | * the attribute header and payload. | |
405 | */ | |
406 | int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) | |
407 | { | |
408 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
409 | return -1; | |
410 | ||
411 | __nla_put(skb, attrtype, attrlen, data); | |
412 | return 0; | |
413 | } | |
414 | ||
fe4944e5 TG |
415 | /** |
416 | * nla_put_nohdr - Add a netlink attribute without header | |
417 | * @skb: socket buffer to add attribute to | |
418 | * @attrlen: length of attribute payload | |
419 | * @data: head of attribute payload | |
420 | * | |
421 | * Returns -1 if the tailroom of the skb is insufficient to store | |
422 | * the attribute payload. | |
423 | */ | |
424 | int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
425 | { | |
426 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
427 | return -1; | |
428 | ||
429 | __nla_put_nohdr(skb, attrlen, data); | |
430 | return 0; | |
431 | } | |
bfa83a9e | 432 | |
01480e1c PM |
433 | /** |
434 | * nla_append - Add a netlink attribute without header or padding | |
435 | * @skb: socket buffer to add attribute to | |
436 | * @attrlen: length of attribute payload | |
437 | * @data: head of attribute payload | |
438 | * | |
439 | * Returns -1 if the tailroom of the skb is insufficient to store | |
440 | * the attribute payload. | |
441 | */ | |
442 | int nla_append(struct sk_buff *skb, int attrlen, const void *data) | |
443 | { | |
444 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
445 | return -1; | |
446 | ||
447 | memcpy(skb_put(skb, attrlen), data, attrlen); | |
448 | return 0; | |
449 | } | |
450 | ||
bfa83a9e TG |
451 | EXPORT_SYMBOL(nla_validate); |
452 | EXPORT_SYMBOL(nla_parse); | |
453 | EXPORT_SYMBOL(nla_find); | |
454 | EXPORT_SYMBOL(nla_strlcpy); | |
455 | EXPORT_SYMBOL(__nla_reserve); | |
fe4944e5 | 456 | EXPORT_SYMBOL(__nla_reserve_nohdr); |
bfa83a9e | 457 | EXPORT_SYMBOL(nla_reserve); |
fe4944e5 | 458 | EXPORT_SYMBOL(nla_reserve_nohdr); |
bfa83a9e | 459 | EXPORT_SYMBOL(__nla_put); |
fe4944e5 | 460 | EXPORT_SYMBOL(__nla_put_nohdr); |
bfa83a9e | 461 | EXPORT_SYMBOL(nla_put); |
fe4944e5 | 462 | EXPORT_SYMBOL(nla_put_nohdr); |
bfa83a9e TG |
463 | EXPORT_SYMBOL(nla_memcpy); |
464 | EXPORT_SYMBOL(nla_memcmp); | |
465 | EXPORT_SYMBOL(nla_strcmp); | |
01480e1c | 466 | EXPORT_SYMBOL(nla_append); |