summaryrefslogtreecommitdiff
path: root/src/reclaim/oidc_helper.c
blob: 646e58551c42d271d0b86e0300fd87c8fbab6bef (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
/*
      This file is part of GNUnet
      Copyright (C) 2010-2015 GNUnet e.V.

      GNUnet 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 of the License,
      or (at your option) any later version.

      GNUnet 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 this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file reclaim/oidc_helper.c
 * @brief helper library for OIDC related functions
 * @author Martin Schanzenbach
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_signatures.h"
#include "gnunet_reclaim_service.h"
#include "gnunet_reclaim_attribute_lib.h"
#include <jansson.h>
#include <inttypes.h>
#include "oidc_helper.h"

static char*
create_jwt_header(void)
{
  json_t *root;
  char *json_str;

  root = json_object ();
  json_object_set_new (root, JWT_ALG, json_string (JWT_ALG_VALUE));
  json_object_set_new (root, JWT_TYP, json_string (JWT_TYP_VALUE));

  json_str = json_dumps (root, JSON_INDENT(0) | JSON_COMPACT);
  json_decref (root);
  return json_str;
}

static void
replace_char(char* str, char find, char replace){
  char *current_pos = strchr(str,find);
  while (current_pos){
    *current_pos = replace;
    current_pos = strchr(current_pos,find);
  }
}

//RFC4648
static void
fix_base64(char* str) {
  //Replace + with -
  replace_char (str, '+', '-');

  //Replace / with _
  replace_char (str, '/', '_');

}

/**
 * Create a JWT from attributes
 *
 * @param aud_key the public of the audience
 * @param sub_key the public key of the subject
 * @param attrs the attribute list
 * @param expiration_time the validity of the token
 * @param secret_key the key used to sign the JWT
 * @return a new base64-encoded JWT string.
 */
char*
OIDC_id_token_new (const struct GNUNET_CRYPTO_EcdsaPublicKey *aud_key,
                   const struct GNUNET_CRYPTO_EcdsaPublicKey *sub_key,
                   const struct GNUNET_RECLAIM_ATTRIBUTE_ClaimList *attrs,
                   const struct GNUNET_TIME_Relative *expiration_time,
                   const char *nonce,
                   const char *secret_key)
{
  struct GNUNET_RECLAIM_ATTRIBUTE_ClaimListEntry *le;
  struct GNUNET_HashCode signature;
  struct GNUNET_TIME_Absolute exp_time;
  struct GNUNET_TIME_Absolute time_now;
  char* audience;
  char* subject;
  char* header;
  char* body_str;
  char* result;
  char* header_base64;
  char* body_base64;
  char* signature_target;
  char* signature_base64;
  char* attr_val_str;
  json_t* body;

  //iat REQUIRED time now
  time_now = GNUNET_TIME_absolute_get();
  //exp REQUIRED time expired from config
  exp_time = GNUNET_TIME_absolute_add (time_now, *expiration_time);
  //auth_time only if max_age
  //nonce only if nonce
  // OPTIONAL acr,amr,azp
  subject = GNUNET_STRINGS_data_to_string_alloc (sub_key,
                                                 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey));
  audience = GNUNET_STRINGS_data_to_string_alloc (aud_key,
                                                  sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey));
  header = create_jwt_header ();
  body = json_object ();

  //iss REQUIRED case sensitive server uri with https
  //The issuer is the local reclaim instance (e.g. https://reclaim.id/api/openid)
  json_object_set_new (body,
                       "iss", json_string (SERVER_ADDRESS));
  //sub REQUIRED public key identity, not exceed 255 ASCII  length
  json_object_set_new (body,
                       "sub", json_string (subject));
  //aud REQUIRED public key client_id must be there
  json_object_set_new (body,
                       "aud", json_string (audience));
  //iat
  json_object_set_new (body,
                       "iat", json_integer (time_now.abs_value_us / (1000*1000)));
  //exp
  json_object_set_new (body,
                       "exp", json_integer (exp_time.abs_value_us / (1000*1000)));
  //nbf
  json_object_set_new (body,
                       "nbf", json_integer (time_now.abs_value_us / (1000*1000)));
  //nonce
  if (NULL != nonce)
    json_object_set_new (body,
                         "nonce", json_string (nonce));

  for (le = attrs->list_head; NULL != le; le = le->next)
  {
    attr_val_str = GNUNET_RECLAIM_ATTRIBUTE_value_to_string (le->claim->type,
                                                             le->claim->data,
                                                             le->claim->data_size);
    json_object_set_new (body,
                         le->claim->name,
                         json_string (attr_val_str));
    GNUNET_free (attr_val_str);
  }
  body_str = json_dumps (body, JSON_INDENT(0) | JSON_COMPACT);
  json_decref (body);

  GNUNET_STRINGS_base64_encode (header,
                                strlen (header),
                                &header_base64);
  fix_base64(header_base64);

  GNUNET_STRINGS_base64_encode (body_str,
                                strlen (body_str),
                                &body_base64);
  fix_base64(body_base64);

  GNUNET_free (subject);
  GNUNET_free (audience);

  /**
   * Creating the JWT signature. This might not be
   * standards compliant, check.
   */
  GNUNET_asprintf (&signature_target, "%s.%s", header_base64, body_base64);
  GNUNET_CRYPTO_hmac_raw (secret_key, strlen (secret_key), signature_target, strlen (signature_target), &signature);
  GNUNET_STRINGS_base64_encode ((const char*)&signature,
                                sizeof (struct GNUNET_HashCode),
                                &signature_base64);
  fix_base64(signature_base64);

  GNUNET_asprintf (&result, "%s.%s.%s",
                   header_base64, body_base64, signature_base64);

  GNUNET_free (signature_target);
  GNUNET_free (header);
  GNUNET_free (body_str);
  GNUNET_free (signature_base64);
  GNUNET_free (body_base64);
  GNUNET_free (header_base64);
  return result;
}
/**
 * Builds an OIDC authorization code including
 * a reclaim ticket and nonce
 *
 * @param issuer the issuer of the ticket, used to sign the ticket and nonce
 * @param ticket the ticket to include in the code
 * @param nonce the nonce to include in the code
 * @return a new authorization code (caller must free)
 */
char*
OIDC_build_authz_code (const struct GNUNET_CRYPTO_EcdsaPrivateKey *issuer,
                       const struct GNUNET_RECLAIM_Ticket *ticket,
                       const char* nonce)
{
  char *ticket_str;
  json_t *code_json;
  char *signature_payload;
  char *signature_str;
  char *authz_code;
  size_t signature_payload_len;
  struct GNUNET_CRYPTO_EcdsaSignature signature;
  struct GNUNET_CRYPTO_EccSignaturePurpose *purpose;

  signature_payload_len = sizeof (struct GNUNET_RECLAIM_Ticket);
  if (NULL != nonce)
    signature_payload_len += strlen (nonce);

  signature_payload = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) + signature_payload_len);
  purpose = (struct GNUNET_CRYPTO_EccSignaturePurpose *)signature_payload;
  purpose->size = htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) + signature_payload_len);
  purpose->purpose = htonl (GNUNET_SIGNATURE_PURPOSE_RECLAIM_CODE_SIGN);
  memcpy (&purpose[1],
          ticket,
          sizeof (struct GNUNET_RECLAIM_Ticket));
  if (NULL != nonce)
    memcpy (((char*)&purpose[1]) + sizeof (struct GNUNET_RECLAIM_Ticket),
            nonce,
            strlen (nonce));
  if (GNUNET_SYSERR == GNUNET_CRYPTO_ecdsa_sign (issuer,
                                                 purpose,
                                                 &signature))
  {
    GNUNET_free (signature_payload);
    return NULL;
  }
  signature_str = GNUNET_STRINGS_data_to_string_alloc (&signature,
                                                       sizeof (signature));
  ticket_str = GNUNET_STRINGS_data_to_string_alloc (ticket,
                                                    sizeof (struct GNUNET_RECLAIM_Ticket));

  code_json = json_object ();
  json_object_set_new (code_json,
                       "ticket",
                       json_string (ticket_str));
  if (NULL != nonce)
    json_object_set_new (code_json,
                         "nonce",
                         json_string (nonce));
  json_object_set_new (code_json,
                       "signature",
                       json_string (signature_str));
  authz_code = json_dumps (code_json,
                           JSON_INDENT(0) | JSON_COMPACT);
  GNUNET_free (signature_payload);
  GNUNET_free (signature_str);
  GNUNET_free (ticket_str);
  json_decref (code_json);
  return authz_code;
}




/**
 * Parse reclaim ticket and nonce from
 * authorization code.
 * This also verifies the signature in the code.
 *
 * @param audience the expected audience of the code
 * @param code the string representation of the code
 * @param ticket where to store the ticket
 * @param nonce where to store the nonce
 * @return GNUNET_OK if successful, else GNUNET_SYSERR
 */
int
OIDC_parse_authz_code (const struct GNUNET_CRYPTO_EcdsaPublicKey *audience,
                       const char* code,
                       struct GNUNET_RECLAIM_Ticket **ticket,
                       char **nonce)
{
  json_error_t error;
  json_t *code_json;
  json_t *ticket_json;
  json_t *nonce_json;
  json_t *signature_json;
  const char *ticket_str;
  const char *signature_str;
  const char *nonce_str;
  char *code_output;
  struct GNUNET_CRYPTO_EccSignaturePurpose *purpose;
  struct GNUNET_CRYPTO_EcdsaSignature signature;
  size_t signature_payload_len;

  code_output = NULL; 
  GNUNET_STRINGS_base64_decode (code,
                                strlen(code),
                                (void**)&code_output);
  code_json = json_loads (code_output, 0 , &error);
  GNUNET_free (code_output);
  ticket_json = json_object_get (code_json, "ticket");
  nonce_json = json_object_get (code_json, "nonce");
  signature_json = json_object_get (code_json, "signature");
  *ticket = NULL;
  *nonce = NULL;

  if ((NULL == ticket_json || !json_is_string (ticket_json)) ||
      (NULL == signature_json || !json_is_string (signature_json)))
  {
    json_decref (code_json);
    return GNUNET_SYSERR;
  }
  ticket_str = json_string_value (ticket_json);
  signature_str = json_string_value (signature_json);
  nonce_str = NULL;
  if (NULL != nonce_json)
    nonce_str = json_string_value (nonce_json);
  signature_payload_len = sizeof (struct GNUNET_RECLAIM_Ticket);
  if (NULL != nonce_str)
    signature_payload_len += strlen (nonce_str);
  purpose = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
                           signature_payload_len);
  purpose->size = htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) + signature_payload_len);
  purpose->purpose = htonl (GNUNET_SIGNATURE_PURPOSE_RECLAIM_CODE_SIGN);
  if (GNUNET_OK != GNUNET_STRINGS_string_to_data (ticket_str,
                                                  strlen (ticket_str),
                                                  &purpose[1],
                                                  sizeof (struct GNUNET_RECLAIM_Ticket)))
  {
    GNUNET_free (purpose);
    json_decref (code_json);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Cannot parse ticket!\n");
    return GNUNET_SYSERR;
  }
  if (GNUNET_OK != GNUNET_STRINGS_string_to_data (signature_str,
                                                  strlen (signature_str),
                                                  &signature,
                                                  sizeof (struct GNUNET_CRYPTO_EcdsaSignature)))
  {
    GNUNET_free (purpose);
    json_decref (code_json);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Cannot parse signature!\n");
    return GNUNET_SYSERR;
  }
  *ticket = GNUNET_new (struct GNUNET_RECLAIM_Ticket);
  memcpy (*ticket,
          &purpose[1],
          sizeof (struct GNUNET_RECLAIM_Ticket));
  if (0 != memcmp (audience,
                   &(*ticket)->audience,
                   sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)))
  {
    GNUNET_free (purpose);
    GNUNET_free (*ticket);
    json_decref (code_json);
    *ticket = NULL;
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Audience in ticket does not match client!\n");
    return GNUNET_SYSERR;

  }
  if (NULL != nonce_str)
    memcpy (((char*)&purpose[1]) + sizeof (struct GNUNET_RECLAIM_Ticket),
            nonce_str,
            strlen (nonce_str));
  if (GNUNET_OK != GNUNET_CRYPTO_ecdsa_verify (GNUNET_SIGNATURE_PURPOSE_RECLAIM_CODE_SIGN,
                                               purpose,
                                               &signature,
                                               &(*ticket)->identity))
  {
    GNUNET_free (purpose);
    GNUNET_free (*ticket);
    json_decref (code_json);
    *ticket = NULL;
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Signature of authZ code invalid!\n");
    return GNUNET_SYSERR;
  }
  *nonce = GNUNET_strdup (nonce_str);
  return GNUNET_OK;
}

/**
 * Build a token response for a token request
 * TODO: Maybe we should add the scope here?
 *
 * @param access_token the access token to include
 * @param id_token the id_token to include
 * @param expiration_time the expiration time of the token(s)
 * @param token_response where to store the response
 */
void
OIDC_build_token_response (const char *access_token,
                           const char *id_token,
                           const struct GNUNET_TIME_Relative *expiration_time,
                           char **token_response)
{
  json_t *root_json;

  root_json = json_object ();

  GNUNET_assert (NULL != access_token);
  GNUNET_assert (NULL != id_token);
  GNUNET_assert (NULL != expiration_time);
  json_object_set_new (root_json,
                       "access_token",
                       json_string (access_token));
  json_object_set_new (root_json,
                       "token_type",
                       json_string ("Bearer"));
  json_object_set_new (root_json,
                       "expires_in",
                       json_integer (expiration_time->rel_value_us / (1000 * 1000)));
  json_object_set_new (root_json,
                       "id_token",
                       json_string (id_token));
  *token_response = json_dumps (root_json,
                                JSON_INDENT(0) | JSON_COMPACT);
  json_decref (root_json);
}

/**
 * Generate a new access token
 */
char*
OIDC_access_token_new ()
{
  char* access_token_number;
  char* access_token;
  uint64_t random_number;

  random_number = GNUNET_CRYPTO_random_u64(GNUNET_CRYPTO_QUALITY_NONCE, UINT64_MAX);
  GNUNET_asprintf (&access_token_number, "%" PRIu64, random_number);
  GNUNET_STRINGS_base64_encode(access_token_number,strlen(access_token_number),&access_token);
  return access_token;
}