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 + 1);
  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_parse_attr(const struct blobmsg_policy *policy, int policy_len,
 183                    struct blob_attr **tb, struct blob_attr *data)
 184 {
 185     return blobmsg_parse(policy, policy_len, tb, blobmsg_data(data), blobmsg_len(data));
 186 }
 187
 188 static inline int
 189 blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
 190 {
 191         union {
 192                 double d;
 193                 uint64_t u64;
 194         } v;
 195         v.d = val;
 196         v.u64 = cpu_to_be64(v.u64);
 197         return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
 198 }
 199
 200 static inline int
 201 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
 202 {
 203         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
 204 }
 205
 206 static inline int
 207 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
 208 {
 209         val = cpu_to_be16(val);
 210         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
 211 }
 212
 213 static inline int
 214 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
 215 {
 216         val = cpu_to_be32(val);
 217         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
 218 }
 219
 220 static inline int
 221 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
 222 {
 223         val = cpu_to_be64(val);
 224         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
 225 }
 226
 227 static inline int
 228 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
 229 {
 230         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
 231 }
 232
 233 static inline int
 234 blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
 235 {
 236         return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
 237                                  blobmsg_data(attr), blobmsg_data_len(attr));
 238 }
 239
 240 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 241
 242 static inline void *
 243 blobmsg_open_array(struct blob_buf *buf, const char *name)
 244 {
 245         return blobmsg_open_nested(buf, name, true);
 246 }
 247
 248 static inline void *
 249 blobmsg_open_table(struct blob_buf *buf, const char *name)
 250 {
 251         return blobmsg_open_nested(buf, name, false);
 252 }
 253
 254 static inline void
 255 blobmsg_close_array(struct blob_buf *buf, void *cookie)
 256 {
 257         blob_nest_end(buf, cookie);
 258 }
 259
 260 static inline void
 261 blobmsg_close_table(struct blob_buf *buf, void *cookie)
 262 {
 263         blob_nest_end(buf, cookie);
 264 }
 265
 266 static inline int blobmsg_buf_init(struct blob_buf *buf)
 267 {
 268         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
 269 }
 270
 271 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
 272 {
 273         return *(uint8_t *) blobmsg_data(attr);
 274 }
 275
 276 static inline bool blobmsg_get_bool(struct blob_attr *attr)
 277 {
 278         return *(uint8_t *) blobmsg_data(attr);
 279 }
 280
 281 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
 282 {
 283         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
 284 }
 285
 286 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
 287 {
 288         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
 289 }
 290
 291 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 292 {
 293         uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
 294         uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
 295         tmp |= be32_to_cpu(ptr[1]);
 296         return tmp;
 297 }
 298
 299 static inline uint64_t blobmsg_cast_u64(struct blob_attr *attr)
 300 {
 301         uint64_t tmp = 0;
 302
 303         if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
 304                 tmp = blobmsg_get_u64(attr);
 305         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
 306                 tmp = blobmsg_get_u32(attr);
 307         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
 308                 tmp = blobmsg_get_u16(attr);
 309         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
 310                 tmp = blobmsg_get_u8(attr);
 311
 312         return tmp;
 313 }
 314
 315 static inline int64_t blobmsg_cast_s64(struct blob_attr *attr)
 316 {
 317         int64_t tmp = 0;
 318
 319         if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
 320                 tmp = blobmsg_get_u64(attr);
 321         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
 322                 tmp = (int32_t)blobmsg_get_u32(attr);
 323         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
 324                 tmp = (int16_t)blobmsg_get_u16(attr);
 325         else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
 326                 tmp = (int8_t)blobmsg_get_u8(attr);
 327
 328         return tmp;
 329 }
 330
 331 static inline double blobmsg_get_double(struct blob_attr *attr)
 332 {
 333         union {
 334                 double d;
 335                 uint64_t u64;
 336         } v;
 337         v.u64 = blobmsg_get_u64(attr);
 338         return v.d;
 339 }
 340
 341 static inline char *blobmsg_get_string(struct blob_attr *attr)
 342 {
 343         if (!attr)
 344                 return NULL;
 345
 346         return (char *) blobmsg_data(attr);
 347 }
 348
 349 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
 350 void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
 351 void blobmsg_add_string_buffer(struct blob_buf *buf);
 352
 353 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
 354 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 355      __attribute__((format(printf, 3, 4)));
 356
 357 #define blobmsg_for_each_attr(pos, attr, rem) \
 358         for (rem = attr ? blobmsg_data_len(attr) : 0, \
 359              pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 360              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 361              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 362              rem -= blob_pad_len(pos), pos = blob_next(pos))
 363
 364 #define __blobmsg_for_each_attr(pos, attr, rem) \
 365         for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 366              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 367              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 368              rem -= blob_pad_len(pos), pos = blob_next(pos))
 369
 370 #endif