aboutsummaryrefslogtreecommitdiff
path: root/src/mint/taler-mint-httpd_parsing.c
blob: 9a3fc1d6bd03587846bc0827072228e227c0a616 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
/*
  This file is part of TALER
  (C) 2014 GNUnet e.V.

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
*/

/**
 * @file taler-mint-httpd_parsing.c
 * @brief functions to parse incoming requests (MHD arguments and JSON snippets)
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */

#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include "taler-mint-httpd_parsing.h"
#include "taler-mint-httpd_responses.h"


/**
 * Initial size for POST
 * request buffer.
 */
#define REQUEST_BUFFER_INITIAL 1024

/**
 * Maximum POST request size
 */
#define REQUEST_BUFFER_MAX (1024*1024)


/**
 * Buffer for POST requests.
 */
struct Buffer
{
  /**
   * Allocated memory
   */
  char *data;

  /**
   * Number of valid bytes in buffer.
   */
  size_t fill;

  /**
   * Number of allocated bytes in buffer.
   */
  size_t alloc;
};


/**
 * Initialize a buffer.
 *
 * @param buf the buffer to initialize
 * @param data the initial data
 * @param data_size size of the initial data
 * @param alloc_size size of the buffer
 * @param max_size maximum size that the buffer can grow to
 * @return a GNUnet result code
 */
static int
buffer_init (struct Buffer *buf,
             const void *data,
             size_t data_size,
             size_t alloc_size,
             size_t max_size)
{
  if (data_size > max_size || alloc_size > max_size)
    return GNUNET_SYSERR;
  if (data_size > alloc_size)
    alloc_size = data_size;
  buf->data = GNUNET_malloc (alloc_size);
  memcpy (buf->data, data, data_size);
  return GNUNET_OK;
}


/**
 * Free the data in a buffer.  Does *not* free
 * the buffer object itself.
 *
 * @param buf buffer to de-initialize
 */
static void
buffer_deinit (struct Buffer *buf)
{
  GNUNET_free (buf->data);
  buf->data = NULL;
}


/**
 * Append data to a buffer, growing the buffer if necessary.
 *
 * @param buf the buffer to append to
 * @param data the data to append
 * @param size the size of @a data
 * @param max_size maximum size that the buffer can grow to
 * @return GNUNET_OK on success,
 *         GNUNET_NO if the buffer can't accomodate for the new data
 *         GNUNET_SYSERR on fatal error (out of memory?)
 */
static int
buffer_append (struct Buffer *buf,
               const void *data,
               size_t data_size,
               size_t max_size)
{
  if (buf->fill + data_size > max_size)
    return GNUNET_NO;
  if (data_size + buf->fill > buf->alloc)
  {
    char *new_buf;
    size_t new_size = buf->alloc;
    while (new_size < buf->fill + data_size)
      new_size += 2;
    if (new_size > max_size)
      return GNUNET_NO;
    new_buf = GNUNET_malloc (new_size);
    memcpy (new_buf, buf->data, buf->fill);
    buf->data = new_buf;
    buf->alloc = new_size;
  }
  memcpy (buf->data + buf->fill, data, data_size);
  buf->fill += data_size;
  return GNUNET_OK;
}


/**
 * Process a POST request containing a JSON object.
 *
 * @param connection the MHD connection
 * @param con_cs the closure (contains a 'struct Buffer *')
 * @param upload_data the POST data
 * @param upload_data_size the POST data size
 * @param json the JSON object for a completed request
 *
 * @returns
 *    GNUNET_YES if json object was parsed
 *    GNUNET_NO is request incomplete or invalid
 *    GNUNET_SYSERR on internal error
 */
int
TALER_MINT_parse_post_json (struct MHD_Connection *connection,
                            void **con_cls,
                            const char *upload_data,
                            size_t *upload_data_size,
                            json_t **json)
{
  struct Buffer *r = *con_cls;

  if (NULL == *con_cls)
  {
    /* We are seeing a fresh POST request. */

    r = GNUNET_new (struct Buffer);
    if (GNUNET_OK !=
        buffer_init (r,
                     upload_data,
                     *upload_data_size,
                     REQUEST_BUFFER_INITIAL,
                     REQUEST_BUFFER_MAX))
    {
      *con_cls = NULL;
      buffer_deinit (r);
      GNUNET_free (r);
      return GNUNET_SYSERR;
    }
    *upload_data_size = 0;
    *con_cls = r;
    return GNUNET_NO;
  }
  if (0 != *upload_data_size)
  {
    /* We are seeing an old request with more data available. */

    if (GNUNET_OK !=
        buffer_append (r,
                       upload_data,
                       *upload_data_size,
                       REQUEST_BUFFER_MAX))
    {
      /* Request too long or we're out of memory. */

      *con_cls = NULL;
      buffer_deinit (r);
      GNUNET_free (r);
      return GNUNET_SYSERR;
    }
    *upload_data_size = 0;
    return GNUNET_NO;
  }

  /* We have seen the whole request. */

  *json = json_loadb (r->data, r->fill, 0, NULL);
  buffer_deinit (r);
  GNUNET_free (r);
  if (NULL == *json)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Can't parse JSON request body\n");
    return (MHD_YES ==
            TALER_MINT_reply_json_pack (connection,
                                        MHD_HTTP_BAD_REQUEST,
                                        "{s:s}",
                                        "error", "invalid json"))
      ? GNUNET_NO : GNUNET_SYSERR;
  }
  *con_cls = NULL;

  return GNUNET_YES;
}


/**
 * Function called whenever we are done with a request
 * to clean up our state.
 *
 * @param con_cls value as it was left by
 *        #TALER_MINT_parse_post_json(), to be cleaned up
 */
void
TALER_MINT_parse_post_cleanup_callback (void *con_cls)
{
  struct Buffer *r = con_cls;

  if (NULL != r)
    buffer_deinit (r);
}


/**
 * Navigate through a JSON tree.
 *
 * Sends an error response if navigation is impossible (i.e.
 * the JSON object is invalid)
 *
 * @param connection the connection to send an error response to
 * @param root the JSON node to start the navigation at.
 * @param ... navigation specification (see JNAV_*)
 * @return GNUNET_YES if navigation was successful
 *         GNUNET_NO if json is malformed, error response was generated
 *         GNUNET_SYSERR on internal error
 */
int
request_json_require_nav (struct MHD_Connection *connection,
                          const json_t *root, ...)
{
  va_list argp;
  int ignore = GNUNET_NO;
  // what's our current path from 'root'?
  json_t *path;

  path = json_array ();

  va_start(argp, root);

  while (1)
  {
    int command = va_arg(argp, int);
    switch (command)
    {
      case JNAV_FIELD:
        {
          const char *fname = va_arg(argp, const char *);
          if (GNUNET_YES == ignore)
            break;
          json_array_append_new (path, json_string (fname));
          root = json_object_get (root, fname);
          if (NULL == root)
          {
            /* FIXME: can't IGNORE this return value! */
            (void) TALER_MINT_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s,s:o}",
                                               "error",
                                               "missing field in JSON",
                                               "path",
                                               path);
            ignore = GNUNET_YES;
            break;
          }
        }
        break;
      case JNAV_INDEX:
        {
          int fnum = va_arg(argp, int);
          if (GNUNET_YES == ignore)
            break;
          json_array_append_new (path, json_integer (fnum));
          root = json_array_get (root, fnum);
          if (NULL == root)
          {
            /* FIXME: can't IGNORE this return value! */
            (void) TALER_MINT_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "missing index in JSON",
                                               "path", path);
            ignore = GNUNET_YES;
            break;
          }
        }
        break;
      case JNAV_RET_DATA:
        {
          void *where = va_arg (argp, void *);
          size_t len = va_arg (argp, size_t);
          const char *str;
          int res;

          va_end(argp);
          if (GNUNET_YES == ignore)
            return GNUNET_NO;
          str = json_string_value (root);
          if (NULL == str)
          {
            /* FIXME: can't IGNORE this return value! */
            (void) TALER_MINT_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error",
                                               "string expected",
                                               "path",
                                               path);
            return GNUNET_NO;
          }
          res = GNUNET_STRINGS_string_to_data (str, strlen (str),
                                                where, len);
          if (GNUNET_OK != res)
          {
            /* FIXME: can't IGNORE this return value! */
            (void) TALER_MINT_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s,s:o}",
                                               "error",
                                               "malformed binary data in JSON",
                                               "path", path);
            return GNUNET_NO;
          }
          return GNUNET_YES;
        }
        break;
      case JNAV_RET_DATA_VAR:
        {
          void **where = va_arg (argp, void **);
          size_t *len = va_arg (argp, size_t *);
          const char *str;

          va_end(argp);
          if (GNUNET_YES == ignore)
            return GNUNET_NO;
          str = json_string_value (root);
          if (NULL == str)
          {
            GNUNET_break (0);
            return GNUNET_SYSERR;
          }
          *len = (strlen (str) * 5) / 8;
          if (where != NULL)
          {
            int res;
            *where = GNUNET_malloc (*len);
            res = GNUNET_STRINGS_string_to_data (str, strlen (str),
                                                  *where, *len);
            if (GNUNET_OK != res)
            {
              /* FIXME: can't IGNORE this return value! */
              (void) TALER_MINT_reply_json_pack (connection,
                                                 MHD_HTTP_BAD_REQUEST,
                                                 "{s:s, s:o}",
                                                 "error",
                                                 "malformed binary data in JSON",
                                                 "path", path);
              return GNUNET_NO;
            }
          }
          return GNUNET_OK;
        }
        break;
      case JNAV_RET_TYPED_JSON:
        {
          int typ = va_arg (argp, int);
          const json_t **r_json = va_arg (argp, const json_t **);

          va_end(argp);
          if (GNUNET_YES == ignore)
            return GNUNET_NO;
          if (typ != -1 && json_typeof (root) != typ)
          {
            /* FIXME: can't IGNORE this return value! */
              (void) TALER_MINT_reply_json_pack (connection,
                                                 MHD_HTTP_BAD_REQUEST,
                                                 "{s:s, s:i, s:i s:o}",
                                                 "error", "wrong JSON field type",
                                                 "type_expected", typ,
                                                 "type_actual", json_typeof (root),
                                                 "path", path);
            return GNUNET_NO;
          }
          *r_json = root;
          return GNUNET_OK;
        }
        break;
      default:
        GNUNET_assert (0);
    }
  }
  GNUNET_assert (0);
}


/**
 * Extract base32crockford encoded data from request.
 *
 * Queues an error response to the connection if the parameter is missing or
 * invalid.
 *
 * @param connection the MHD connection
 * @param param_name the name of the parameter with the key
 * @param[out] out_data pointer to store the result
 * @param out_size expected size of data
 * @return
 *   GNUNET_YES if the the argument is present
 *   GNUNET_NO if the argument is absent or malformed
 *   GNUNET_SYSERR on internal error (error response could not be sent)
 */
int
TALER_MINT_mhd_request_arg_data (struct MHD_Connection *connection,
                                 const char *param_name,
                                 void *out_data,
                                 size_t out_size)
{
  const char *str;

  str = MHD_lookup_connection_value (connection,
                                     MHD_GET_ARGUMENT_KIND,
                                     param_name);
  if (NULL == str)
  {
    return (MHD_NO ==
            TALER_MINT_reply_arg_missing (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  }
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data (str,
                                     strlen (str),
                                     out_data,
                                     out_size))
    return (MHD_NO ==
            TALER_MINT_reply_arg_invalid (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  return GNUNET_OK;
}

/* end of taler-mint-httpd_parsing.c */