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Sources/libubox/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_parse_array_attr(const struct blobmsg_policy *policy, int policy_len,
190                          struct blob_attr **tb, struct blob_attr *data)
191 {
192         return blobmsg_parse_array(policy, policy_len, tb, blobmsg_data(data), blobmsg_len(data));
193 }
194 
195 static inline int
196 blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
197 {
198         union {
199                 double d;
200                 uint64_t u64;
201         } v;
202         v.d = val;
203         v.u64 = cpu_to_be64(v.u64);
204         return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
205 }
206 
207 static inline int
208 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
209 {
210         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
211 }
212 
213 static inline int
214 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
215 {
216         val = cpu_to_be16(val);
217         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
218 }
219 
220 static inline int
221 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
222 {
223         val = cpu_to_be32(val);
224         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
225 }
226 
227 static inline int
228 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
229 {
230         val = cpu_to_be64(val);
231         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
232 }
233 
234 static inline int
235 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
236 {
237         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
238 }
239 
240 static inline int
241 blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
242 {
243         return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
244                                  blobmsg_data(attr), blobmsg_data_len(attr));
245 }
246 
247 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
248 
249 static inline void *
250 blobmsg_open_array(struct blob_buf *buf, const char *name)
251 {
252         return blobmsg_open_nested(buf, name, true);
253 }
254 
255 static inline void *
256 blobmsg_open_table(struct blob_buf *buf, const char *name)
257 {
258         return blobmsg_open_nested(buf, name, false);
259 }
260 
261 static inline void
262 blobmsg_close_array(struct blob_buf *buf, void *cookie)
263 {
264         blob_nest_end(buf, cookie);
265 }
266 
267 static inline void
268 blobmsg_close_table(struct blob_buf *buf, void *cookie)
269 {
270         blob_nest_end(buf, cookie);
271 }
272 
273 static inline int blobmsg_buf_init(struct blob_buf *buf)
274 {
275         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
276 }
277 
278 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
279 {
280         return *(uint8_t *) blobmsg_data(attr);
281 }
282 
283 static inline bool blobmsg_get_bool(struct blob_attr *attr)
284 {
285         return *(uint8_t *) blobmsg_data(attr);
286 }
287 
288 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
289 {
290         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
291 }
292 
293 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
294 {
295         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
296 }
297 
298 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
299 {
300         uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
301         uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
302         tmp |= be32_to_cpu(ptr[1]);
303         return tmp;
304 }
305 
306 static inline uint64_t blobmsg_cast_u64(struct blob_attr *attr)
307 {
308         const int type = blobmsg_type(attr);
309         uint64_t tmp;
310 
311         switch (type) {
312         case BLOBMSG_TYPE_INT64:
313                 tmp = blobmsg_get_u64(attr);
314                 break;
315         case BLOBMSG_TYPE_INT32:
316                 tmp = blobmsg_get_u32(attr);
317                 break;
318         case BLOBMSG_TYPE_INT16:
319                 tmp = blobmsg_get_u16(attr);
320                 break;
321         case BLOBMSG_TYPE_INT8:
322                 tmp = blobmsg_get_u8(attr);
323                 break;
324         default:
325                 tmp = 0;
326                 break;
327         }
328 
329         return tmp;
330 }
331 
332 static inline int64_t blobmsg_cast_s64(struct blob_attr *attr)
333 {
334         const int type = blobmsg_type(attr);
335         int64_t tmp;
336 
337         switch (type) {
338         case BLOBMSG_TYPE_INT64:
339                 tmp = blobmsg_get_u64(attr);
340                 break;
341         case BLOBMSG_TYPE_INT32:
342                 tmp = (int32_t) blobmsg_get_u32(attr);
343                 break;
344         case BLOBMSG_TYPE_INT16:
345                 tmp = (int16_t) blobmsg_get_u16(attr);
346                 break;
347         case BLOBMSG_TYPE_INT8:
348                 tmp = (int8_t) blobmsg_get_u8(attr);
349                 break;
350         default:
351                 tmp = 0;
352                 break;
353         }
354 
355         return tmp;
356 }
357 
358 static inline double blobmsg_get_double(struct blob_attr *attr)
359 {
360         union {
361                 double d;
362                 uint64_t u64;
363         } v;
364         v.u64 = blobmsg_get_u64(attr);
365         return v.d;
366 }
367 
368 static inline char *blobmsg_get_string(struct blob_attr *attr)
369 {
370         if (!attr)
371                 return NULL;
372 
373         return (char *) blobmsg_data(attr);
374 }
375 
376 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
377 void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
378 void blobmsg_add_string_buffer(struct blob_buf *buf);
379 
380 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
381 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
382      __attribute__((format(printf, 3, 4)));
383 
384 #define blobmsg_for_each_attr(pos, attr, rem) \
385         for (rem = attr ? blobmsg_data_len(attr) : 0, \
386              pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
387              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
388              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
389              rem -= blob_pad_len(pos), pos = blob_next(pos))
390 
391 #define __blobmsg_for_each_attr(pos, attr, rem) \
392         for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
393              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
394              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
395              rem -= blob_pad_len(pos), pos = blob_next(pos))
396 
397 #endif
398 

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