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, | |
27 | struct nla_policy *policy) | |
28 | { | |
29 | struct nla_policy *pt; | |
a5531a5d | 30 | int minlen = 0, attrlen = nla_len(nla); |
bfa83a9e TG |
31 | |
32 | if (nla->nla_type <= 0 || nla->nla_type > maxtype) | |
33 | return 0; | |
34 | ||
35 | pt = &policy[nla->nla_type]; | |
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 | ||
a5531a5d TG |
75 | default: |
76 | if (pt->len) | |
77 | minlen = pt->len; | |
78 | else if (pt->type != NLA_UNSPEC) | |
79 | minlen = nla_attr_minlen[pt->type]; | |
80 | ||
81 | if (attrlen < minlen) | |
82 | return -ERANGE; | |
83 | } | |
bfa83a9e TG |
84 | |
85 | return 0; | |
86 | } | |
87 | ||
88 | /** | |
89 | * nla_validate - Validate a stream of attributes | |
90 | * @head: head of attribute stream | |
91 | * @len: length of attribute stream | |
92 | * @maxtype: maximum attribute type to be expected | |
93 | * @policy: validation policy | |
94 | * | |
95 | * Validates all attributes in the specified attribute stream against the | |
96 | * specified policy. Attributes with a type exceeding maxtype will be | |
97 | * ignored. See documenation of struct nla_policy for more details. | |
98 | * | |
99 | * Returns 0 on success or a negative error code. | |
100 | */ | |
101 | int nla_validate(struct nlattr *head, int len, int maxtype, | |
102 | struct nla_policy *policy) | |
103 | { | |
104 | struct nlattr *nla; | |
105 | int rem, err; | |
106 | ||
107 | nla_for_each_attr(nla, head, len, rem) { | |
108 | err = validate_nla(nla, maxtype, policy); | |
109 | if (err < 0) | |
110 | goto errout; | |
111 | } | |
112 | ||
113 | err = 0; | |
114 | errout: | |
115 | return err; | |
116 | } | |
117 | ||
118 | /** | |
119 | * nla_parse - Parse a stream of attributes into a tb buffer | |
120 | * @tb: destination array with maxtype+1 elements | |
121 | * @maxtype: maximum attribute type to be expected | |
122 | * @head: head of attribute stream | |
123 | * @len: length of attribute stream | |
124 | * | |
125 | * Parses a stream of attributes and stores a pointer to each attribute in | |
126 | * the tb array accessable via the attribute type. Attributes with a type | |
127 | * exceeding maxtype will be silently ignored for backwards compatibility | |
128 | * reasons. policy may be set to NULL if no validation is required. | |
129 | * | |
130 | * Returns 0 on success or a negative error code. | |
131 | */ | |
132 | int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, | |
133 | struct nla_policy *policy) | |
134 | { | |
135 | struct nlattr *nla; | |
136 | int rem, err; | |
137 | ||
138 | memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); | |
139 | ||
140 | nla_for_each_attr(nla, head, len, rem) { | |
141 | u16 type = nla->nla_type; | |
142 | ||
143 | if (type > 0 && type <= maxtype) { | |
144 | if (policy) { | |
145 | err = validate_nla(nla, maxtype, policy); | |
146 | if (err < 0) | |
147 | goto errout; | |
148 | } | |
149 | ||
150 | tb[type] = nla; | |
151 | } | |
152 | } | |
153 | ||
154 | if (unlikely(rem > 0)) | |
155 | printk(KERN_WARNING "netlink: %d bytes leftover after parsing " | |
156 | "attributes.\n", rem); | |
157 | ||
158 | err = 0; | |
159 | errout: | |
160 | return err; | |
161 | } | |
162 | ||
163 | /** | |
164 | * nla_find - Find a specific attribute in a stream of attributes | |
165 | * @head: head of attribute stream | |
166 | * @len: length of attribute stream | |
167 | * @attrtype: type of attribute to look for | |
168 | * | |
169 | * Returns the first attribute in the stream matching the specified type. | |
170 | */ | |
171 | struct nlattr *nla_find(struct nlattr *head, int len, int attrtype) | |
172 | { | |
173 | struct nlattr *nla; | |
174 | int rem; | |
175 | ||
176 | nla_for_each_attr(nla, head, len, rem) | |
177 | if (nla->nla_type == attrtype) | |
178 | return nla; | |
179 | ||
180 | return NULL; | |
181 | } | |
182 | ||
183 | /** | |
184 | * nla_strlcpy - Copy string attribute payload into a sized buffer | |
185 | * @dst: where to copy the string to | |
186 | * @src: attribute to copy the string from | |
187 | * @dstsize: size of destination buffer | |
188 | * | |
189 | * Copies at most dstsize - 1 bytes into the destination buffer. | |
190 | * The result is always a valid NUL-terminated string. Unlike | |
191 | * strlcpy the destination buffer is always padded out. | |
192 | * | |
193 | * Returns the length of the source buffer. | |
194 | */ | |
195 | size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize) | |
196 | { | |
197 | size_t srclen = nla_len(nla); | |
198 | char *src = nla_data(nla); | |
199 | ||
200 | if (srclen > 0 && src[srclen - 1] == '\0') | |
201 | srclen--; | |
202 | ||
203 | if (dstsize > 0) { | |
204 | size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; | |
205 | ||
206 | memset(dst, 0, dstsize); | |
207 | memcpy(dst, src, len); | |
208 | } | |
209 | ||
210 | return srclen; | |
211 | } | |
212 | ||
213 | /** | |
214 | * nla_memcpy - Copy a netlink attribute into another memory area | |
215 | * @dest: where to copy to memcpy | |
216 | * @src: netlink attribute to copy from | |
217 | * @count: size of the destination area | |
218 | * | |
219 | * Note: The number of bytes copied is limited by the length of | |
220 | * attribute's payload. memcpy | |
221 | * | |
222 | * Returns the number of bytes copied. | |
223 | */ | |
224 | int nla_memcpy(void *dest, struct nlattr *src, int count) | |
225 | { | |
226 | int minlen = min_t(int, count, nla_len(src)); | |
227 | ||
228 | memcpy(dest, nla_data(src), minlen); | |
229 | ||
230 | return minlen; | |
231 | } | |
232 | ||
233 | /** | |
234 | * nla_memcmp - Compare an attribute with sized memory area | |
235 | * @nla: netlink attribute | |
236 | * @data: memory area | |
237 | * @size: size of memory area | |
238 | */ | |
239 | int nla_memcmp(const struct nlattr *nla, const void *data, | |
240 | size_t size) | |
241 | { | |
242 | int d = nla_len(nla) - size; | |
243 | ||
244 | if (d == 0) | |
245 | d = memcmp(nla_data(nla), data, size); | |
246 | ||
247 | return d; | |
248 | } | |
249 | ||
250 | /** | |
251 | * nla_strcmp - Compare a string attribute against a string | |
252 | * @nla: netlink string attribute | |
253 | * @str: another string | |
254 | */ | |
255 | int nla_strcmp(const struct nlattr *nla, const char *str) | |
256 | { | |
257 | int len = strlen(str) + 1; | |
258 | int d = nla_len(nla) - len; | |
259 | ||
260 | if (d == 0) | |
261 | d = memcmp(nla_data(nla), str, len); | |
262 | ||
263 | return d; | |
264 | } | |
265 | ||
266 | /** | |
267 | * __nla_reserve - reserve room for attribute on the skb | |
268 | * @skb: socket buffer to reserve room on | |
269 | * @attrtype: attribute type | |
270 | * @attrlen: length of attribute payload | |
271 | * | |
272 | * Adds a netlink attribute header to a socket buffer and reserves | |
273 | * room for the payload but does not copy it. | |
274 | * | |
275 | * The caller is responsible to ensure that the skb provides enough | |
276 | * tailroom for the attribute header and payload. | |
277 | */ | |
278 | struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
279 | { | |
280 | struct nlattr *nla; | |
281 | ||
282 | nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen)); | |
283 | nla->nla_type = attrtype; | |
284 | nla->nla_len = nla_attr_size(attrlen); | |
285 | ||
286 | memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); | |
287 | ||
288 | return nla; | |
289 | } | |
290 | ||
fe4944e5 TG |
291 | /** |
292 | * __nla_reserve_nohdr - reserve room for attribute without header | |
293 | * @skb: socket buffer to reserve room on | |
294 | * @attrlen: length of attribute payload | |
295 | * | |
296 | * Reserves room for attribute payload without a header. | |
297 | * | |
298 | * The caller is responsible to ensure that the skb provides enough | |
299 | * tailroom for the payload. | |
300 | */ | |
301 | void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
302 | { | |
303 | void *start; | |
304 | ||
305 | start = skb_put(skb, NLA_ALIGN(attrlen)); | |
306 | memset(start, 0, NLA_ALIGN(attrlen)); | |
307 | ||
308 | return start; | |
309 | } | |
310 | ||
bfa83a9e TG |
311 | /** |
312 | * nla_reserve - reserve room for attribute on the skb | |
313 | * @skb: socket buffer to reserve room on | |
314 | * @attrtype: attribute type | |
315 | * @attrlen: length of attribute payload | |
316 | * | |
317 | * Adds a netlink attribute header to a socket buffer and reserves | |
318 | * room for the payload but does not copy it. | |
319 | * | |
320 | * Returns NULL if the tailroom of the skb is insufficient to store | |
321 | * the attribute header and payload. | |
322 | */ | |
323 | struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) | |
324 | { | |
325 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
326 | return NULL; | |
327 | ||
328 | return __nla_reserve(skb, attrtype, attrlen); | |
329 | } | |
330 | ||
fe4944e5 TG |
331 | /** |
332 | * nla_reserve - reserve room for attribute without header | |
333 | * @skb: socket buffer to reserve room on | |
334 | * @len: length of attribute payload | |
335 | * | |
336 | * Reserves room for attribute payload without a header. | |
337 | * | |
338 | * Returns NULL if the tailroom of the skb is insufficient to store | |
339 | * the attribute payload. | |
340 | */ | |
341 | void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) | |
342 | { | |
343 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
344 | return NULL; | |
345 | ||
346 | return __nla_reserve_nohdr(skb, attrlen); | |
347 | } | |
348 | ||
bfa83a9e TG |
349 | /** |
350 | * __nla_put - Add a netlink attribute to a socket buffer | |
351 | * @skb: socket buffer to add attribute to | |
352 | * @attrtype: attribute type | |
353 | * @attrlen: length of attribute payload | |
354 | * @data: head of attribute payload | |
355 | * | |
356 | * The caller is responsible to ensure that the skb provides enough | |
357 | * tailroom for the attribute header and payload. | |
358 | */ | |
359 | void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, | |
360 | const void *data) | |
361 | { | |
362 | struct nlattr *nla; | |
363 | ||
364 | nla = __nla_reserve(skb, attrtype, attrlen); | |
365 | memcpy(nla_data(nla), data, attrlen); | |
366 | } | |
367 | ||
fe4944e5 TG |
368 | /** |
369 | * __nla_put_nohdr - Add a netlink attribute without header | |
370 | * @skb: socket buffer to add attribute to | |
371 | * @attrlen: length of attribute payload | |
372 | * @data: head of attribute payload | |
373 | * | |
374 | * The caller is responsible to ensure that the skb provides enough | |
375 | * tailroom for the attribute payload. | |
376 | */ | |
377 | void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
378 | { | |
379 | void *start; | |
380 | ||
381 | start = __nla_reserve_nohdr(skb, attrlen); | |
382 | memcpy(start, data, attrlen); | |
383 | } | |
bfa83a9e TG |
384 | |
385 | /** | |
386 | * nla_put - Add a netlink attribute to a socket buffer | |
387 | * @skb: socket buffer to add attribute to | |
388 | * @attrtype: attribute type | |
389 | * @attrlen: length of attribute payload | |
390 | * @data: head of attribute payload | |
391 | * | |
392 | * Returns -1 if the tailroom of the skb is insufficient to store | |
393 | * the attribute header and payload. | |
394 | */ | |
395 | int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) | |
396 | { | |
397 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) | |
398 | return -1; | |
399 | ||
400 | __nla_put(skb, attrtype, attrlen, data); | |
401 | return 0; | |
402 | } | |
403 | ||
fe4944e5 TG |
404 | /** |
405 | * nla_put_nohdr - Add a netlink attribute without header | |
406 | * @skb: socket buffer to add attribute to | |
407 | * @attrlen: length of attribute payload | |
408 | * @data: head of attribute payload | |
409 | * | |
410 | * Returns -1 if the tailroom of the skb is insufficient to store | |
411 | * the attribute payload. | |
412 | */ | |
413 | int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) | |
414 | { | |
415 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) | |
416 | return -1; | |
417 | ||
418 | __nla_put_nohdr(skb, attrlen, data); | |
419 | return 0; | |
420 | } | |
bfa83a9e TG |
421 | |
422 | EXPORT_SYMBOL(nla_validate); | |
423 | EXPORT_SYMBOL(nla_parse); | |
424 | EXPORT_SYMBOL(nla_find); | |
425 | EXPORT_SYMBOL(nla_strlcpy); | |
426 | EXPORT_SYMBOL(__nla_reserve); | |
fe4944e5 | 427 | EXPORT_SYMBOL(__nla_reserve_nohdr); |
bfa83a9e | 428 | EXPORT_SYMBOL(nla_reserve); |
fe4944e5 | 429 | EXPORT_SYMBOL(nla_reserve_nohdr); |
bfa83a9e | 430 | EXPORT_SYMBOL(__nla_put); |
fe4944e5 | 431 | EXPORT_SYMBOL(__nla_put_nohdr); |
bfa83a9e | 432 | EXPORT_SYMBOL(nla_put); |
fe4944e5 | 433 | EXPORT_SYMBOL(nla_put_nohdr); |
bfa83a9e TG |
434 | EXPORT_SYMBOL(nla_memcpy); |
435 | EXPORT_SYMBOL(nla_memcmp); | |
436 | EXPORT_SYMBOL(nla_strcmp); |