Commit | Line | Data |
---|---|---|
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 | |
10b595af | 135 | * @policy: validation policy |
bfa83a9e TG |
136 | * |
137 | * Parses a stream of attributes and stores a pointer to each attribute in | |
138 | * the tb array accessable via the attribute type. Attributes with a type | |
139 | * exceeding maxtype will be silently ignored for backwards compatibility | |
140 | * reasons. policy may be set to NULL if no validation is required. | |
141 | * | |
142 | * Returns 0 on success or a negative error code. | |
143 | */ | |
144 | int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, | |
ef7c79ed | 145 | const struct nla_policy *policy) |
bfa83a9e TG |
146 | { |
147 | struct nlattr *nla; | |
148 | int rem, err; | |
149 | ||
150 | memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); | |
151 | ||
152 | nla_for_each_attr(nla, head, len, rem) { | |
8f4c1f9b | 153 | u16 type = nla_type(nla); |
bfa83a9e TG |
154 | |
155 | if (type > 0 && type <= maxtype) { | |
156 | if (policy) { | |
157 | err = validate_nla(nla, maxtype, policy); | |
158 | if (err < 0) | |
159 | goto errout; | |
160 | } | |
161 | ||
162 | tb[type] = nla; | |
163 | } | |
164 | } | |
165 | ||
166 | if (unlikely(rem > 0)) | |
167 | printk(KERN_WARNING "netlink: %d bytes leftover after parsing " | |
168 | "attributes.\n", rem); | |
169 | ||
170 | err = 0; | |
171 | errout: | |
172 | return err; | |
173 | } | |
174 | ||
175 | /** | |
176 | * nla_find - Find a specific attribute in a stream of attributes | |
177 | * @head: head of attribute stream | |
178 | * @len: length of attribute stream | |
179 | * @attrtype: type of attribute to look for | |
180 | * | |
181 | * Returns the first attribute in the stream matching the specified type. | |
182 | */ | |
183 | struct nlattr *nla_find(struct nlattr *head, int len, int attrtype) | |
184 | { | |
185 | struct nlattr *nla; | |
186 | int rem; | |
187 | ||
188 | nla_for_each_attr(nla, head, len, rem) | |
8f4c1f9b | 189 | if (nla_type(nla) == attrtype) |
bfa83a9e TG |
190 | return nla; |
191 | ||
192 | return NULL; | |
193 | } | |
194 | ||
195 | /** | |
196 | * nla_strlcpy - Copy string attribute payload into a sized buffer | |
197 | * @dst: where to copy the string to | |
10b595af | 198 | * @nla: attribute to copy the string from |
bfa83a9e TG |
199 | * @dstsize: size of destination buffer |
200 | * | |
201 | * Copies at most dstsize - 1 bytes into the destination buffer. | |
202 | * The result is always a valid NUL-terminated string. Unlike | |
203 | * strlcpy the destination buffer is always padded out. | |
204 | * | |
205 | * Returns the length of the source buffer. | |
206 | */ | |
207 | size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize) | |
208 | { | |
209 | size_t srclen = nla_len(nla); | |
210 | char *src = nla_data(nla); | |
211 | ||
212 | if (srclen > 0 && src[srclen - 1] == '\0') | |
213 | srclen--; | |
214 | ||
215 | if (dstsize > 0) { | |
216 | size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; | |
217 | ||
218 | memset(dst, 0, dstsize); | |
219 | memcpy(dst, src, len); | |
220 | } | |
221 | ||
222 | return srclen; | |
223 | } | |
224 | ||
225 | /** | |
226 | * nla_memcpy - Copy a netlink attribute into another memory area | |
227 | * @dest: where to copy to memcpy | |
228 | * @src: netlink attribute to copy from | |
229 | * @count: size of the destination area | |
230 | * | |
231 | * Note: The number of bytes copied is limited by the length of | |
232 | * attribute's payload. memcpy | |
233 | * | |
234 | * Returns the number of bytes copied. | |
235 | */ | |
236 | int nla_memcpy(void *dest, struct nlattr *src, int count) | |
237 | { | |
238 | int minlen = min_t(int, count, nla_len(src)); | |
239 | ||
240 | memcpy(dest, nla_data(src), minlen); | |
241 | ||
242 | return minlen; | |
243 | } | |
244 | ||
245 | /** | |
246 | * nla_memcmp - Compare an attribute with sized memory area | |
247 | * @nla: netlink attribute | |
248 | * @data: memory area | |
249 | * @size: size of memory area | |
250 | */ | |
251 | int nla_memcmp(const struct nlattr *nla, const void *data, | |
252 | size_t size) | |
253 | { | |
254 | int d = nla_len(nla) - size; | |
255 | ||
256 | if (d == 0) | |
257 | d = memcmp(nla_data(nla), data, size); | |
258 | ||
259 | return d; | |
260 | } | |
261 | ||
262 | /** | |
263 | * nla_strcmp - Compare a string attribute against a string | |
264 | * @nla: netlink string attribute | |
265 | * @str: another string | |
266 | */ | |
267 | int nla_strcmp(const struct nlattr *nla, const char *str) | |
268 | { | |
269 | int len = strlen(str) + 1; | |
270 | int d = nla_len(nla) - len; | |
271 | ||
272 | if (d == 0) | |
273 | d = memcmp(nla_data(nla), str, len); | |
274 | ||
275 | return d; | |
276 | } | |
277 | ||
278 | /** | |
279 | * __nla_reserve - reserve room for attribute on the skb | |
280 | * @skb: socket buffer to reserve room on | |
281 | * @attrtype: attribute type | |
282 | * @attrlen: length of attribute payload | |
283 | * | |
284 | * Adds a netlink attribute header to a socket buffer and reserves | |
285 | * room for the payload but does not copy it. | |
286 | * | |
287 | * The caller is responsible to ensure that the skb provides enough | |
288 | * tailroom for the attribute header and payload. | |
289 | */ | |
290 | struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
291 | { | |
292 | struct nlattr *nla; | |
293 | ||
294 | nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen)); | |
295 | nla->nla_type = attrtype; | |
296 | nla->nla_len = nla_attr_size(attrlen); | |
297 | ||
298 | memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); | |
299 | ||
300 | return nla; | |
301 | } | |
302 | ||
fe4944e5 TG |
303 | /** |
304 | * __nla_reserve_nohdr - reserve room for attribute without header | |
305 | * @skb: socket buffer to reserve room on | |
306 | * @attrlen: length of attribute payload | |
307 | * | |
308 | * Reserves room for attribute payload without a header. | |
309 | * | |
310 | * The caller is responsible to ensure that the skb provides enough | |
311 | * tailroom for the payload. | |
312 | */ | |
313 | void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
314 | { | |
315 | void *start; | |
316 | ||
317 | start = skb_put(skb, NLA_ALIGN(attrlen)); | |
318 | memset(start, 0, NLA_ALIGN(attrlen)); | |
319 | ||
320 | return start; | |
321 | } | |
322 | ||
bfa83a9e TG |
323 | /** |
324 | * nla_reserve - reserve room for attribute on the skb | |
325 | * @skb: socket buffer to reserve room on | |
326 | * @attrtype: attribute type | |
327 | * @attrlen: length of attribute payload | |
328 | * | |
329 | * Adds a netlink attribute header to a socket buffer and reserves | |
330 | * room for the payload but does not copy it. | |
331 | * | |
332 | * Returns NULL if the tailroom of the skb is insufficient to store | |
333 | * the attribute header and payload. | |
334 | */ | |
335 | struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
336 | { | |
337 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
338 | return NULL; | |
339 | ||
340 | return __nla_reserve(skb, attrtype, attrlen); | |
341 | } | |
342 | ||
fe4944e5 | 343 | /** |
10b595af | 344 | * nla_reserve_nohdr - reserve room for attribute without header |
fe4944e5 | 345 | * @skb: socket buffer to reserve room on |
10b595af | 346 | * @attrlen: length of attribute payload |
fe4944e5 TG |
347 | * |
348 | * Reserves room for attribute payload without a header. | |
349 | * | |
350 | * Returns NULL if the tailroom of the skb is insufficient to store | |
351 | * the attribute payload. | |
352 | */ | |
353 | void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
354 | { | |
355 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
356 | return NULL; | |
357 | ||
358 | return __nla_reserve_nohdr(skb, attrlen); | |
359 | } | |
360 | ||
bfa83a9e TG |
361 | /** |
362 | * __nla_put - Add a netlink attribute to a socket buffer | |
363 | * @skb: socket buffer to add attribute to | |
364 | * @attrtype: attribute type | |
365 | * @attrlen: length of attribute payload | |
366 | * @data: head of attribute payload | |
367 | * | |
368 | * The caller is responsible to ensure that the skb provides enough | |
369 | * tailroom for the attribute header and payload. | |
370 | */ | |
371 | void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, | |
372 | const void *data) | |
373 | { | |
374 | struct nlattr *nla; | |
375 | ||
376 | nla = __nla_reserve(skb, attrtype, attrlen); | |
377 | memcpy(nla_data(nla), data, attrlen); | |
378 | } | |
379 | ||
fe4944e5 TG |
380 | /** |
381 | * __nla_put_nohdr - Add a netlink attribute without header | |
382 | * @skb: socket buffer to add attribute to | |
383 | * @attrlen: length of attribute payload | |
384 | * @data: head of attribute payload | |
385 | * | |
386 | * The caller is responsible to ensure that the skb provides enough | |
387 | * tailroom for the attribute payload. | |
388 | */ | |
389 | void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
390 | { | |
391 | void *start; | |
392 | ||
393 | start = __nla_reserve_nohdr(skb, attrlen); | |
394 | memcpy(start, data, attrlen); | |
395 | } | |
bfa83a9e TG |
396 | |
397 | /** | |
398 | * nla_put - Add a netlink attribute to a socket buffer | |
399 | * @skb: socket buffer to add attribute to | |
400 | * @attrtype: attribute type | |
401 | * @attrlen: length of attribute payload | |
402 | * @data: head of attribute payload | |
403 | * | |
bc3ed28c | 404 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
bfa83a9e TG |
405 | * the attribute header and payload. |
406 | */ | |
407 | int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) | |
408 | { | |
409 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
bc3ed28c | 410 | return -EMSGSIZE; |
bfa83a9e TG |
411 | |
412 | __nla_put(skb, attrtype, attrlen, data); | |
413 | return 0; | |
414 | } | |
415 | ||
fe4944e5 TG |
416 | /** |
417 | * nla_put_nohdr - Add a netlink attribute without header | |
418 | * @skb: socket buffer to add attribute to | |
419 | * @attrlen: length of attribute payload | |
420 | * @data: head of attribute payload | |
421 | * | |
bc3ed28c | 422 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
fe4944e5 TG |
423 | * the attribute payload. |
424 | */ | |
425 | int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
426 | { | |
427 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
bc3ed28c | 428 | return -EMSGSIZE; |
fe4944e5 TG |
429 | |
430 | __nla_put_nohdr(skb, attrlen, data); | |
431 | return 0; | |
432 | } | |
bfa83a9e | 433 | |
01480e1c PM |
434 | /** |
435 | * nla_append - Add a netlink attribute without header or padding | |
436 | * @skb: socket buffer to add attribute to | |
437 | * @attrlen: length of attribute payload | |
438 | * @data: head of attribute payload | |
439 | * | |
bc3ed28c | 440 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
01480e1c PM |
441 | * the attribute payload. |
442 | */ | |
443 | int nla_append(struct sk_buff *skb, int attrlen, const void *data) | |
444 | { | |
445 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
bc3ed28c | 446 | return -EMSGSIZE; |
01480e1c PM |
447 | |
448 | memcpy(skb_put(skb, attrlen), data, attrlen); | |
449 | return 0; | |
450 | } | |
451 | ||
bfa83a9e TG |
452 | EXPORT_SYMBOL(nla_validate); |
453 | EXPORT_SYMBOL(nla_parse); | |
454 | EXPORT_SYMBOL(nla_find); | |
455 | EXPORT_SYMBOL(nla_strlcpy); | |
456 | EXPORT_SYMBOL(__nla_reserve); | |
fe4944e5 | 457 | EXPORT_SYMBOL(__nla_reserve_nohdr); |
bfa83a9e | 458 | EXPORT_SYMBOL(nla_reserve); |
fe4944e5 | 459 | EXPORT_SYMBOL(nla_reserve_nohdr); |
bfa83a9e | 460 | EXPORT_SYMBOL(__nla_put); |
fe4944e5 | 461 | EXPORT_SYMBOL(__nla_put_nohdr); |
bfa83a9e | 462 | EXPORT_SYMBOL(nla_put); |
fe4944e5 | 463 | EXPORT_SYMBOL(nla_put_nohdr); |
bfa83a9e TG |
464 | EXPORT_SYMBOL(nla_memcpy); |
465 | EXPORT_SYMBOL(nla_memcmp); | |
466 | EXPORT_SYMBOL(nla_strcmp); | |
01480e1c | 467 | EXPORT_SYMBOL(nla_append); |