blobmsg.h

   1 /*
   2  * Copyright (C) 2010-2012 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 #ifndef __BLOBMSG_H
  17 #define __BLOBMSG_H
  18
  19 #include <stdarg.h>
  20 #include "blob.h"
  21
  22 #define BLOBMSG_ALIGN   2
  23 #define BLOBMSG_PADDING(len) (((len) + (1 << BLOBMSG_ALIGN) - 1) & ~((1 << BLOBMSG_ALIGN) - 1))
  24
  25 enum blobmsg_type {
  26         BLOBMSG_TYPE_UNSPEC,
  27         BLOBMSG_TYPE_ARRAY,
  28         BLOBMSG_TYPE_TABLE,
  29         BLOBMSG_TYPE_STRING,
  30         BLOBMSG_TYPE_INT64,
  31         BLOBMSG_TYPE_INT32,
  32         BLOBMSG_TYPE_INT16,
  33         BLOBMSG_TYPE_INT8,
  34         BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
  35         BLOBMSG_TYPE_DOUBLE,
  36         __BLOBMSG_TYPE_LAST,
  37         BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
  38         BLOBMSG_CAST_INT64 = __BLOBMSG_TYPE_LAST,
  39 };
  40
  41 struct blobmsg_hdr {
  42         uint16_t namelen;
  43         uint8_t name[];
  44 } __packed;
  45
  46 struct blobmsg_policy {
  47         const char *name;
  48         enum blobmsg_type type;
  49 };
  50
  51 static inline int blobmsg_hdrlen(unsigned int namelen)
  52 {
  53         return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
  54 }
  55
  56 static inline void blobmsg_clear_name(struct blob_attr *attr)
  57 {
  58         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  59         hdr->name[0] = 0;
  60 }
  61
  62 static inline const char *blobmsg_name(const struct blob_attr *attr)
  63 {
  64         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  65         return (const char *) hdr->name;
  66 }
  67
  68 static inline int blobmsg_type(const struct blob_attr *attr)
  69 {
  70         return blob_id(attr);
  71 }
  72
  73 static uint16_t blobmsg_namelen(const struct blobmsg_hdr *hdr)
  74 {
  75         return be16_to_cpu(hdr->namelen);
  76 }
  77
  78 static inline void *blobmsg_data(const struct blob_attr *attr)
  79 {
  80         struct blobmsg_hdr *hdr;
  81         char *data;
  82
  83         if (!attr)
  84                 return NULL;
  85
  86         hdr = (struct blobmsg_hdr *) blob_data(attr);
  87         data = (char *) blob_data(attr);
  88
  89         if (blob_is_extended(attr))
  90                 data += blobmsg_hdrlen(blobmsg_namelen(hdr));
  91
  92         return data;
  93 }
  94
  95 static inline size_t blobmsg_data_len(const struct blob_attr *attr)
  96 {
  97         uint8_t *start, *end;
  98
  99         if (!attr)
 100                 return 0;
 101
 102         start = (uint8_t *) blob_data(attr);
 103         end = (uint8_t *) blobmsg_data(attr);
 104
 105         return blob_len(attr) - (end - start);
 106 }
 107
 108 static inline size_t blobmsg_len(const struct blob_attr *attr)
 109 {
 110         return blobmsg_data_len(attr);
 111 }
 112
 113 /*
 114  * blobmsg_check_attr: validate a list of attributes
 115  *
 116  * This method may be used with trusted data only. Providing
 117  * malformed blobs will cause out of bounds memory access.
 118  */
 119 bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
 120
 121 /*
 122  * blobmsg_check_attr_len: validate a list of attributes
 123  *
 124  * This method should be safer implementation of blobmsg_check_attr.
 125  * It will limit all memory access performed on the blob to the
 126  * range [attr, attr + len] (upper bound non inclusive) and is
 127  * thus suited for checking of untrusted blob attributes.
 128  */
 129 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len);
 130
 131 /*
 132  * blobmsg_check_attr_list: validate a list of attributes
 133  *
 134  * This method may be used with trusted data only. Providing
 135  * malformed blobs will cause out of bounds memory access.
 136  */
 137 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
 138
 139 /*
 140  * blobmsg_check_attr_list_len: validate a list of untrusted attributes
 141  *
 142  * This method should be safer implementation of blobmsg_check_attr_list.
 143  * It will limit all memory access performed on the blob to the
 144  * range [attr, attr + len] (upper bound non inclusive) and is
 145  * thus suited for checking of untrusted blob attributes.
 146  */
 147 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len);
 148
 149 /*
 150  * blobmsg_check_array: validate array/table and return size
 151  *
 152  * Checks if all elements of an array or table are valid and have
 153  * the specified type. Returns the number of elements in the array
 154  *
 155  * This method may be used with trusted data only. Providing
 156  * malformed blobs will cause out of bounds memory access.
 157  */
 158 int blobmsg_check_array(const struct blob_attr *attr, int type);
 159
 160 /*
 161  * blobmsg_check_array_len: validate untrusted array/table and return size
 162  *
 163  * Checks if all elements of an array or table are valid and have
 164  * the specified type. Returns the number of elements in the array.
 165  *
 166  * This method should be safer implementation of blobmsg_check_array.
 167  * It will limit all memory access performed on the blob to the
 168  * range [attr, attr + len] (upper bound non inclusive) and is
 169  * thus suited for checking of untrusted blob attributes.
 170  */
 171 int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len);
 172
 173 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 174                   struct blob_attr **tb, void *data, unsigned int len);
 175 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 176                         struct blob_attr **tb, void *data, unsigned int len);
 177
 178 int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 179                       const void *data, unsigned int len);
 180
 181 static inline int
 182 blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
 183 {
 184         union {
 185                 double d;
 186                 uint64_t u64;
 187         } v;
 188         v.d = val;
 189         v.u64 = cpu_to_be64(v.u64);
 190         return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
 191 }
 192
 193 static inline int
 194 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
 195 {
 196         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
 197 }
 198
 199 static inline int
 200 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
 201 {
 202         val = cpu_to_be16(val);
 203         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
 204 }
 205
 206 static inline int
 207 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
 208 {
 209         val = cpu_to_be32(val);
 210         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
 211 }
 212
 213 static inline int
 214 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
 215 {
 216         val = cpu_to_be64(val);
 217         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
 218 }
 219
 220 static inline int
 221 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
 222 {
 223         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
 224 }
 225
 226 static inline int
 227 blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
 228 {
 229         return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
 230                                  blobmsg_data(attr), blobmsg_data_len(attr));
 231 }
 232
 233 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 234
 235 static inline void *
 236 blobmsg_open_array(struct blob_buf *buf, const char *name)
 237 {
 238         return blobmsg_open_nested(buf, name, true);
 239 }
 240
 241 static inline void *
 242 blobmsg_open_table(struct blob_buf *buf, const char *name)
 243 {
 244         return blobmsg_open_nested(buf, name, false);
 245 }
 246
 247 static inline void
 248 blobmsg_close_array(struct blob_buf *buf, void *cookie)
 249 {
 250         blob_nest_end(buf, cookie);
 251 }
 252
 253 static inline void
 254 blobmsg_close_table(struct blob_buf *buf, void *cookie)
 255 {
 256         blob_nest_end(buf, cookie);
 257 }
 258
 259 static inline int blobmsg_buf_init(struct blob_buf *buf)
 260 {
 261         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
 262 }
 263
 264 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
 265 {
 266         return *(uint8_t *) blobmsg_data(attr);
 267 }
 268
 269 static inline bool blobmsg_get_bool(struct blob_attr *attr)
 270 {
 271         return *(uint8_t *) blobmsg_data(attr);
 272 }
 273
 274 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
 275 {
 276         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
 277 }
 278
 279 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
 280 {
 281         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
 282 }
 283
 284 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 285 {
 286         uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
 287         uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
 288         tmp |= be32_to_cpu(ptr[1]);
 289         return tmp;
 290 }
 291
 292 static inline uint64_t blobmsg_cast_u64(struct blob_attr *attr)
 293 {
 294         uint64_t tmp = 0;
 295
 296         if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
 297                 tmp = blobmsg_get_u64(attr);
 298         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
 299                 tmp = blobmsg_get_u32(attr);
 300         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
 301                 tmp = blobmsg_get_u16(attr);
 302         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
 303                 tmp = blobmsg_get_u8(attr);
 304
 305         return tmp;
 306 }
 307
 308 static inline int64_t blobmsg_cast_s64(struct blob_attr *attr)
 309 {
 310         int64_t tmp = 0;
 311
 312         if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
 313                 tmp = blobmsg_get_u64(attr);
 314         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
 315                 tmp = (int32_t)blobmsg_get_u32(attr);
 316         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
 317                 tmp = (int16_t)blobmsg_get_u16(attr);
 318         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
 319                 tmp = (int8_t)blobmsg_get_u8(attr);
 320
 321         return tmp;
 322 }
 323
 324 static inline double blobmsg_get_double(struct blob_attr *attr)
 325 {
 326         union {
 327                 double d;
 328                 uint64_t u64;
 329         } v;
 330         v.u64 = blobmsg_get_u64(attr);
 331         return v.d;
 332 }
 333
 334 static inline char *blobmsg_get_string(struct blob_attr *attr)
 335 {
 336         if (!attr)
 337                 return NULL;
 338
 339         return (char *) blobmsg_data(attr);
 340 }
 341
 342 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
 343 void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
 344 void blobmsg_add_string_buffer(struct blob_buf *buf);
 345
 346 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
 347 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 348      __attribute__((format(printf, 3, 4)));
 349
 350 #define blobmsg_for_each_attr(pos, attr, rem) \
 351         for (rem = attr ? blobmsg_data_len(attr) : 0, \
 352              pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 353              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 354              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 355              rem -= blob_pad_len(pos), pos = blob_next(pos))
 356
 357 #define __blobmsg_for_each_attr(pos, attr, rem) \
 358         for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 359              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 360              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 361              rem -= blob_pad_len(pos), pos = blob_next(pos))
 362
 363 #endif