Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 1 | /* |
| 2 | * NETLINK Netlink attributes |
| 3 | * |
| 4 | * Authors: Thomas Graf <tgraf@suug.ch> |
| 5 | * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> |
| 6 | */ |
| 7 | |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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), |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 23 | [NLA_NESTED] = NLA_HDRLEN, |
| 24 | }; |
| 25 | |
| 26 | static int validate_nla(struct nlattr *nla, int maxtype, |
Patrick McHardy | ef7c79e | 2007-06-05 12:38:30 -0700 | [diff] [blame] | 27 | const struct nla_policy *policy) |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 28 | { |
Patrick McHardy | ef7c79e | 2007-06-05 12:38:30 -0700 | [diff] [blame] | 29 | const struct nla_policy *pt; |
Thomas Graf | a5531a5 | 2006-08-26 20:11:47 -0700 | [diff] [blame] | 30 | int minlen = 0, attrlen = nla_len(nla); |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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 | |
Thomas Graf | a5531a5 | 2006-08-26 20:11:47 -0700 | [diff] [blame] | 39 | switch (pt->type) { |
| 40 | case NLA_FLAG: |
| 41 | if (attrlen > 0) |
| 42 | return -ERANGE; |
| 43 | break; |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 44 | |
Thomas Graf | a5531a5 | 2006-08-26 20:11:47 -0700 | [diff] [blame] | 45 | case NLA_NUL_STRING: |
| 46 | if (pt->len) |
| 47 | minlen = min_t(int, attrlen, pt->len + 1); |
| 48 | else |
| 49 | minlen = attrlen; |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 50 | |
Thomas Graf | a5531a5 | 2006-08-26 20:11:47 -0700 | [diff] [blame] | 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 | |
Johannes Berg | d30045a | 2007-03-23 11:37:48 -0700 | [diff] [blame] | 70 | case NLA_BINARY: |
| 71 | if (pt->len && attrlen > pt->len) |
| 72 | return -ERANGE; |
| 73 | break; |
| 74 | |
Thomas Graf | a5531a5 | 2006-08-26 20:11:47 -0700 | [diff] [blame] | 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 | } |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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, |
Patrick McHardy | ef7c79e | 2007-06-05 12:38:30 -0700 | [diff] [blame] | 102 | const struct nla_policy *policy) |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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, |
Patrick McHardy | ef7c79e | 2007-06-05 12:38:30 -0700 | [diff] [blame] | 133 | const struct nla_policy *policy) |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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 | |
| 291 | /** |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 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 | |
| 311 | /** |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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 | |
| 331 | /** |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 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 | |
| 349 | /** |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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 | |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 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 | } |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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 | |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 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 | } |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 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); |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 427 | EXPORT_SYMBOL(__nla_reserve_nohdr); |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 428 | EXPORT_SYMBOL(nla_reserve); |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 429 | EXPORT_SYMBOL(nla_reserve_nohdr); |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 430 | EXPORT_SYMBOL(__nla_put); |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 431 | EXPORT_SYMBOL(__nla_put_nohdr); |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 432 | EXPORT_SYMBOL(nla_put); |
Thomas Graf | fe4944e | 2006-08-04 23:03:05 -0700 | [diff] [blame] | 433 | EXPORT_SYMBOL(nla_put_nohdr); |
Thomas Graf | bfa83a9 | 2005-11-10 02:25:51 +0100 | [diff] [blame] | 434 | EXPORT_SYMBOL(nla_memcpy); |
| 435 | EXPORT_SYMBOL(nla_memcmp); |
| 436 | EXPORT_SYMBOL(nla_strcmp); |