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_DOUBLE,
  35         __BLOBMSG_TYPE_LAST,
  36         BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
  37         BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
  38 };
  39
  40 struct blobmsg_hdr {
  41         uint16_t namelen;
  42         uint8_t name[];
  43 } __packed;
  44
  45 struct blobmsg_policy {
  46         const char *name;
  47         enum blobmsg_type type;
  48 };
  49
  50 static inline int blobmsg_hdrlen(unsigned int namelen)
  51 {
  52         return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
  53 }
  54
  55 static inline void blobmsg_clear_name(struct blob_attr *attr)
  56 {
  57         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  58         hdr->name[0] = 0;
  59 }
  60
  61 static inline const char *blobmsg_name(const struct blob_attr *attr)
  62 {
  63         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  64         return (const char *) hdr->name;
  65 }
  66
  67 static inline int blobmsg_type(const struct blob_attr *attr)
  68 {
  69         return blob_id(attr);
  70 }
  71
  72 static uint16_t blobmsg_namelen(const struct blobmsg_hdr *hdr)
  73 {
  74         return be16_to_cpu(hdr->namelen);
  75 }
  76
  77 static inline void *blobmsg_data(const struct blob_attr *attr)
  78 {
  79         struct blobmsg_hdr *hdr;
  80         char *data;
  81
  82         if (!attr)
  83                 return NULL;
  84
  85         hdr = (struct blobmsg_hdr *) blob_data(attr);
  86         data = (char *) blob_data(attr);
  87
  88         if (blob_is_extended(attr))
  89                 data += blobmsg_hdrlen(blobmsg_namelen(hdr));
  90
  91         return data;
  92 }
  93
  94 static inline size_t blobmsg_data_len(const struct blob_attr *attr)
  95 {
  96         uint8_t *start, *end;
  97
  98         if (!attr)
  99                 return 0;
 100
 101         start = (uint8_t *) blob_data(attr);
 102         end = (uint8_t *) blobmsg_data(attr);
 103
 104         return blob_len(attr) - (end - start);
 105 }
 106
 107 static inline size_t blobmsg_len(const struct blob_attr *attr)
 108 {
 109         return blobmsg_data_len(attr);
 110 }
 111
 112 /*
 113  * blobmsg_check_attr: validate a list of attributes
 114  *
 115  * This method may be used with trusted data only. Providing
 116  * malformed blobs will cause out of bounds memory access.
 117  */
 118 bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
 119
 120 /*
 121  * blobmsg_check_attr_len: validate a list of attributes
 122  *
 123  * This method should be safer implementation of blobmsg_check_attr.
 124  * It will limit all memory access performed on the blob to the
 125  * range [attr, attr + len] (upper bound non inclusive) and is
 126  * thus suited for checking of untrusted blob attributes.
 127  */
 128 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len);
 129
 130 /*
 131  * blobmsg_check_attr_list: validate a list of attributes
 132  *
 133  * This method may be used with trusted data only. Providing
 134  * malformed blobs will cause out of bounds memory access.
 135  */
 136 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
 137
 138 /*
 139  * blobmsg_check_attr_list_len: validate a list of untrusted attributes
 140  *
 141  * This method should be safer implementation of blobmsg_check_attr_list.
 142  * It will limit all memory access performed on the blob to the
 143  * range [attr, attr + len] (upper bound non inclusive) and is
 144  * thus suited for checking of untrusted blob attributes.
 145  */
 146 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len);
 147
 148 /*
 149  * blobmsg_check_array: validate array/table and return size
 150  *
 151  * Checks if all elements of an array or table are valid and have
 152  * the specified type. Returns the number of elements in the array
 153  *
 154  * This method may be used with trusted data only. Providing
 155  * malformed blobs will cause out of bounds memory access.
 156  */
 157 int blobmsg_check_array(const struct blob_attr *attr, int type);
 158
 159 /*
 160  * blobmsg_check_array_len: validate untrusted array/table and return size
 161  *
 162  * Checks if all elements of an array or table are valid and have
 163  * the specified type. Returns the number of elements in the array.
 164  *
 165  * This method should be safer implementation of blobmsg_check_array.
 166  * It will limit all memory access performed on the blob to the
 167  * range [attr, attr + len] (upper bound non inclusive) and is
 168  * thus suited for checking of untrusted blob attributes.
 169  */
 170 int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len);
 171
 172 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 173                   struct blob_attr **tb, void *data, unsigned int len);
 174 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 175                         struct blob_attr **tb, void *data, unsigned int len);
 176
 177 int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 178                       const void *data, unsigned int len);
 179
 180 static inline int
 181 blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
 182 {
 183         union {
 184                 double d;
 185                 uint64_t u64;
 186         } v;
 187         v.d = val;
 188         v.u64 = cpu_to_be64(v.u64);
 189         return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
 190 }
 191
 192 static inline int
 193 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
 194 {
 195         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
 196 }
 197
 198 static inline int
 199 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
 200 {
 201         val = cpu_to_be16(val);
 202         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
 203 }
 204
 205 static inline int
 206 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
 207 {
 208         val = cpu_to_be32(val);
 209         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
 210 }
 211
 212 static inline int
 213 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
 214 {
 215         val = cpu_to_be64(val);
 216         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
 217 }
 218
 219 static inline int
 220 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
 221 {
 222         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
 223 }
 224
 225 static inline int
 226 blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
 227 {
 228         return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
 229                                  blobmsg_data(attr), blobmsg_data_len(attr));
 230 }
 231
 232 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 233
 234 static inline void *
 235 blobmsg_open_array(struct blob_buf *buf, const char *name)
 236 {
 237         return blobmsg_open_nested(buf, name, true);
 238 }
 239
 240 static inline void *
 241 blobmsg_open_table(struct blob_buf *buf, const char *name)
 242 {
 243         return blobmsg_open_nested(buf, name, false);
 244 }
 245
 246 static inline void
 247 blobmsg_close_array(struct blob_buf *buf, void *cookie)
 248 {
 249         blob_nest_end(buf, cookie);
 250 }
 251
 252 static inline void
 253 blobmsg_close_table(struct blob_buf *buf, void *cookie)
 254 {
 255         blob_nest_end(buf, cookie);
 256 }
 257
 258 static inline int blobmsg_buf_init(struct blob_buf *buf)
 259 {
 260         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
 261 }
 262
 263 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
 264 {
 265         return *(uint8_t *) blobmsg_data(attr);
 266 }
 267
 268 static inline bool blobmsg_get_bool(struct blob_attr *attr)
 269 {
 270         return *(uint8_t *) blobmsg_data(attr);
 271 }
 272
 273 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
 274 {
 275         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
 276 }
 277
 278 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
 279 {
 280         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
 281 }
 282
 283 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 284 {
 285         uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
 286         uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
 287         tmp |= be32_to_cpu(ptr[1]);
 288         return tmp;
 289 }
 290
 291 static inline double blobmsg_get_double(struct blob_attr *attr)
 292 {
 293         union {
 294                 double d;
 295                 uint64_t u64;
 296         } v;
 297         v.u64 = blobmsg_get_u64(attr);
 298         return v.d;
 299 }
 300
 301 static inline char *blobmsg_get_string(struct blob_attr *attr)
 302 {
 303         if (!attr)
 304                 return NULL;
 305
 306         return (char *) blobmsg_data(attr);
 307 }
 308
 309 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
 310 void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
 311 void blobmsg_add_string_buffer(struct blob_buf *buf);
 312
 313 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
 314 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 315      __attribute__((format(printf, 3, 4)));
 316
 317 #define blobmsg_for_each_attr(pos, attr, rem) \
 318         for (rem = attr ? blobmsg_data_len(attr) : 0, \
 319              pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 320              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 321              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 322              rem -= blob_pad_len(pos), pos = blob_next(pos))
 323
 324 #define __blobmsg_for_each_attr(pos, attr, rem) \
 325         for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 326              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 327              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 328              rem -= blob_pad_len(pos), pos = blob_next(pos))
 329
 330 #endif