summaryrefslogtreecommitdiff
path: root/lib/socks_gssapi.c
blob: f195c1a0e4d99c102125636c653b144957294acc (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
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2009, 2011, Markus Moeller, <markus_moeller@compuserve.com>
 * Copyright (C) 2012 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#ifndef CURL_DISABLE_PROXY

#ifdef HAVE_GSSAPI
#ifdef HAVE_OLD_GSSMIT
#define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
#define NCOMPAT 1
#endif
#ifndef gss_nt_service_name
#define gss_nt_service_name GSS_C_NT_HOSTBASED_SERVICE
#endif

#include "curl_gssapi.h"
#include "urldata.h"
#include "sendf.h"
#include "connect.h"
#include "timeval.h"
#include "socks.h"
#include "warnless.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"

static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;

/*
 * Helper GSS-API error functions.
 */
static int check_gss_err(struct SessionHandle *data,
                         OM_uint32 major_status,
                         OM_uint32 minor_status,
                         const char* function)
{
  if(GSS_ERROR(major_status)) {
    OM_uint32 maj_stat,min_stat;
    OM_uint32 msg_ctx = 0;
    gss_buffer_desc status_string;
    char buf[1024];
    size_t len;

    len = 0;
    msg_ctx = 0;
    while(!msg_ctx) {
      /* convert major status code (GSS-API error) to text */
      maj_stat = gss_display_status(&min_stat, major_status,
                                    GSS_C_GSS_CODE,
                                    GSS_C_NULL_OID,
                                    &msg_ctx, &status_string);
      if(maj_stat == GSS_S_COMPLETE) {
        if(sizeof(buf) > len + status_string.length + 1) {
          strcpy(buf+len, (char*) status_string.value);
          len += status_string.length;
        }
        gss_release_buffer(&min_stat, &status_string);
        break;
      }
      gss_release_buffer(&min_stat, &status_string);
    }
    if(sizeof(buf) > len + 3) {
      strcpy(buf+len, ".\n");
      len += 2;
    }
    msg_ctx = 0;
    while(!msg_ctx) {
      /* convert minor status code (underlying routine error) to text */
      maj_stat = gss_display_status(&min_stat, minor_status,
                                    GSS_C_MECH_CODE,
                                    GSS_C_NULL_OID,
                                    &msg_ctx, &status_string);
      if(maj_stat == GSS_S_COMPLETE) {
        if(sizeof(buf) > len + status_string.length)
          strcpy(buf+len, (char*) status_string.value);
        gss_release_buffer(&min_stat, &status_string);
        break;
      }
      gss_release_buffer(&min_stat, &status_string);
    }
    failf(data, "GSS-API error: %s failed:\n%s", function, buf);
    return(1);
  }

  return(0);
}

CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
                                      struct connectdata *conn)
{
  struct SessionHandle *data = conn->data;
  curl_socket_t sock = conn->sock[sockindex];
  CURLcode code;
  ssize_t actualread;
  ssize_t written;
  int result;
  OM_uint32 gss_major_status, gss_minor_status, gss_status;
  OM_uint32 gss_ret_flags;
  int gss_conf_state, gss_enc;
  gss_buffer_desc  service = GSS_C_EMPTY_BUFFER;
  gss_buffer_desc  gss_send_token = GSS_C_EMPTY_BUFFER;
  gss_buffer_desc  gss_recv_token = GSS_C_EMPTY_BUFFER;
  gss_buffer_desc  gss_w_token = GSS_C_EMPTY_BUFFER;
  gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
  gss_name_t       server = GSS_C_NO_NAME;
  gss_name_t       gss_client_name = GSS_C_NO_NAME;
  unsigned short   us_length;
  char             *user=NULL;
  unsigned char socksreq[4]; /* room for GSS-API exchange header only */
  char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];

  /*   GSS-API request looks like
   * +----+------+-----+----------------+
   * |VER | MTYP | LEN |     TOKEN      |
   * +----+------+----------------------+
   * | 1  |  1   |  2  | up to 2^16 - 1 |
   * +----+------+-----+----------------+
   */

  /* prepare service name */
  if(strchr(serviceptr,'/')) {
    service.value = malloc(strlen(serviceptr));
    if(!service.value)
      return CURLE_OUT_OF_MEMORY;
    service.length = strlen(serviceptr);
    memcpy(service.value, serviceptr, service.length);

    gss_major_status = gss_import_name(&gss_minor_status, &service,
                                       (gss_OID) GSS_C_NULL_OID, &server);
  }
  else {
    service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
    if(!service.value)
      return CURLE_OUT_OF_MEMORY;
    service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
    snprintf(service.value, service.length+1, "%s@%s",
             serviceptr, conn->proxy.name);

    gss_major_status = gss_import_name(&gss_minor_status, &service,
                                       gss_nt_service_name, &server);
  }

  gss_release_buffer(&gss_status, &service); /* clear allocated memory */

  if(check_gss_err(data,gss_major_status,
                   gss_minor_status,"gss_import_name()")) {
    failf(data, "Failed to create service name.");
    gss_release_name(&gss_status, &server);
    return CURLE_COULDNT_CONNECT;
  }

  /* As long as we need to keep sending some context info, and there's no  */
  /* errors, keep sending it...                                            */
  for(;;) {
    gss_major_status = Curl_gss_init_sec_context(data,
                                                 &gss_minor_status,
                                                 &gss_context,
                                                 server,
                                                 &Curl_krb5_mech_oid,
                                                 NULL,
                                                 gss_token,
                                                 &gss_send_token,
                                                 TRUE,
                                                 &gss_ret_flags);

    if(gss_token != GSS_C_NO_BUFFER)
      gss_release_buffer(&gss_status, &gss_recv_token);
    if(check_gss_err(data,gss_major_status,
                     gss_minor_status,"gss_init_sec_context")) {
      gss_release_name(&gss_status, &server);
      gss_release_buffer(&gss_status, &gss_recv_token);
      gss_release_buffer(&gss_status, &gss_send_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      failf(data, "Failed to initial GSS-API token.");
      return CURLE_COULDNT_CONNECT;
    }

    if(gss_send_token.length != 0) {
      socksreq[0] = 1;    /* GSS-API subnegotiation version */
      socksreq[1] = 1;    /* authentication message type */
      us_length = htons((short)gss_send_token.length);
      memcpy(socksreq+2,&us_length,sizeof(short));

      code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
      if(code || (4 != written)) {
        failf(data, "Failed to send GSS-API authentication request.");
        gss_release_name(&gss_status, &server);
        gss_release_buffer(&gss_status, &gss_recv_token);
        gss_release_buffer(&gss_status, &gss_send_token);
        gss_delete_sec_context(&gss_status, &gss_context, NULL);
        return CURLE_COULDNT_CONNECT;
      }

      code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
                              gss_send_token.length, &written);

      if(code || ((ssize_t)gss_send_token.length != written)) {
        failf(data, "Failed to send GSS-API authentication token.");
        gss_release_name(&gss_status, &server);
        gss_release_buffer(&gss_status, &gss_recv_token);
        gss_release_buffer(&gss_status, &gss_send_token);
        gss_delete_sec_context(&gss_status, &gss_context, NULL);
        return CURLE_COULDNT_CONNECT;
      }

    }

    gss_release_buffer(&gss_status, &gss_send_token);
    gss_release_buffer(&gss_status, &gss_recv_token);
    if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;

    /* analyse response */

    /*   GSS-API response looks like
     * +----+------+-----+----------------+
     * |VER | MTYP | LEN |     TOKEN      |
     * +----+------+----------------------+
     * | 1  |  1   |  2  | up to 2^16 - 1 |
     * +----+------+-----+----------------+
     */

    result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
    if(result || (actualread != 4)) {
      failf(data, "Failed to receive GSS-API authentication response.");
      gss_release_name(&gss_status, &server);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    /* ignore the first (VER) byte */
    if(socksreq[1] == 255) { /* status / message type */
      failf(data, "User was rejected by the SOCKS5 server (%d %d).",
            socksreq[0], socksreq[1]);
      gss_release_name(&gss_status, &server);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    if(socksreq[1] != 1) { /* status / messgae type */
      failf(data, "Invalid GSS-API authentication response type (%d %d).",
            socksreq[0], socksreq[1]);
      gss_release_name(&gss_status, &server);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    memcpy(&us_length, socksreq+2, sizeof(short));
    us_length = ntohs(us_length);

    gss_recv_token.length=us_length;
    gss_recv_token.value=malloc(us_length);
    if(!gss_recv_token.value) {
      failf(data,
            "Could not allocate memory for GSS-API authentication "
            "response token.");
      gss_release_name(&gss_status, &server);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_OUT_OF_MEMORY;
    }

    result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
                              gss_recv_token.length, &actualread);

    if(result || (actualread != us_length)) {
      failf(data, "Failed to receive GSS-API authentication token.");
      gss_release_name(&gss_status, &server);
      gss_release_buffer(&gss_status, &gss_recv_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    gss_token = &gss_recv_token;
  }

  gss_release_name(&gss_status, &server);

  /* Everything is good so far, user was authenticated! */
  gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
                                          &gss_client_name, NULL, NULL, NULL,
                                          NULL, NULL, NULL);
  if(check_gss_err(data,gss_major_status,
                   gss_minor_status,"gss_inquire_context")) {
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    gss_release_name(&gss_status, &gss_client_name);
    failf(data, "Failed to determine user name.");
    return CURLE_COULDNT_CONNECT;
  }
  gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
                                      &gss_send_token, NULL);
  if(check_gss_err(data,gss_major_status,
                   gss_minor_status,"gss_display_name")) {
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    gss_release_name(&gss_status, &gss_client_name);
    gss_release_buffer(&gss_status, &gss_send_token);
    failf(data, "Failed to determine user name.");
    return CURLE_COULDNT_CONNECT;
  }
  user=malloc(gss_send_token.length+1);
  if(!user) {
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    gss_release_name(&gss_status, &gss_client_name);
    gss_release_buffer(&gss_status, &gss_send_token);
    return CURLE_OUT_OF_MEMORY;
  }

  memcpy(user, gss_send_token.value, gss_send_token.length);
  user[gss_send_token.length] = '\0';
  gss_release_name(&gss_status, &gss_client_name);
  gss_release_buffer(&gss_status, &gss_send_token);
  infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
  free(user);
  user=NULL;

  /* Do encryption */
  socksreq[0] = 1;    /* GSS-API subnegotiation version */
  socksreq[1] = 2;    /* encryption message type */

  gss_enc = 0; /* no data protection */
  /* do confidentiality protection if supported */
  if(gss_ret_flags & GSS_C_CONF_FLAG)
    gss_enc = 2;
  /* else do integrity protection */
  else if(gss_ret_flags & GSS_C_INTEG_FLAG)
    gss_enc = 1;

  infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
        (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
  /* force for the moment to no data protection */
  gss_enc = 0;
  /*
   * Sending the encryption type in clear seems wrong. It should be
   * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
   * The NEC reference implementations on which this is based is
   * therefore at fault
   *
   *  +------+------+------+.......................+
   *  + ver  | mtyp | len  |   token               |
   *  +------+------+------+.......................+
   *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
   *  +------+------+------+.......................+
   *
   *   Where:
   *
   *  - "ver" is the protocol version number, here 1 to represent the
   *    first version of the SOCKS/GSS-API protocol
   *
   *  - "mtyp" is the message type, here 2 to represent a protection
   *    -level negotiation message
   *
   *  - "len" is the length of the "token" field in octets
   *
   *  - "token" is the GSS-API encapsulated protection level
   *
   * The token is produced by encapsulating an octet containing the
   * required protection level using gss_seal()/gss_wrap() with conf_req
   * set to FALSE.  The token is verified using gss_unseal()/
   * gss_unwrap().
   *
   */
  if(data->set.socks5_gssapi_nec) {
    us_length = htons((short)1);
    memcpy(socksreq+2,&us_length,sizeof(short));
  }
  else {
    gss_send_token.length = 1;
    gss_send_token.value = malloc(1);
    if(!gss_send_token.value) {
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_OUT_OF_MEMORY;
    }
    memcpy(gss_send_token.value, &gss_enc, 1);

    gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
                                GSS_C_QOP_DEFAULT, &gss_send_token,
                                &gss_conf_state, &gss_w_token);

    if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_wrap")) {
      gss_release_buffer(&gss_status, &gss_send_token);
      gss_release_buffer(&gss_status, &gss_w_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      failf(data, "Failed to wrap GSS-API encryption value into token.");
      return CURLE_COULDNT_CONNECT;
    }
    gss_release_buffer(&gss_status, &gss_send_token);

    us_length = htons((short)gss_w_token.length);
    memcpy(socksreq+2,&us_length,sizeof(short));
  }

  code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
  if(code  || (4 != written)) {
    failf(data, "Failed to send GSS-API encryption request.");
    gss_release_buffer(&gss_status, &gss_w_token);
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_COULDNT_CONNECT;
  }

  if(data->set.socks5_gssapi_nec) {
    memcpy(socksreq, &gss_enc, 1);
    code = Curl_write_plain(conn, sock, socksreq, 1, &written);
    if(code || ( 1 != written)) {
      failf(data, "Failed to send GSS-API encryption type.");
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }
  }
  else {
    code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
                            gss_w_token.length, &written);
    if(code || ((ssize_t)gss_w_token.length != written)) {
      failf(data, "Failed to send GSS-API encryption type.");
      gss_release_buffer(&gss_status, &gss_w_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }
    gss_release_buffer(&gss_status, &gss_w_token);
  }

  result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
  if(result || (actualread != 4)) {
    failf(data, "Failed to receive GSS-API encryption response.");
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_COULDNT_CONNECT;
  }

  /* ignore the first (VER) byte */
  if(socksreq[1] == 255) { /* status / message type */
    failf(data, "User was rejected by the SOCKS5 server (%d %d).",
          socksreq[0], socksreq[1]);
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_COULDNT_CONNECT;
  }

  if(socksreq[1] != 2) { /* status / messgae type */
    failf(data, "Invalid GSS-API encryption response type (%d %d).",
          socksreq[0], socksreq[1]);
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_COULDNT_CONNECT;
  }

  memcpy(&us_length, socksreq+2, sizeof(short));
  us_length = ntohs(us_length);

  gss_recv_token.length= us_length;
  gss_recv_token.value=malloc(gss_recv_token.length);
  if(!gss_recv_token.value) {
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_OUT_OF_MEMORY;
  }
  result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
                            gss_recv_token.length, &actualread);

  if(result || (actualread != us_length)) {
    failf(data, "Failed to receive GSS-API encryptrion type.");
    gss_release_buffer(&gss_status, &gss_recv_token);
    gss_delete_sec_context(&gss_status, &gss_context, NULL);
    return CURLE_COULDNT_CONNECT;
  }

  if(!data->set.socks5_gssapi_nec) {
    gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
                                  &gss_recv_token, &gss_w_token,
                                  0, GSS_C_QOP_DEFAULT);

    if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_unwrap")) {
      gss_release_buffer(&gss_status, &gss_recv_token);
      gss_release_buffer(&gss_status, &gss_w_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      failf(data, "Failed to unwrap GSS-API encryption value into token.");
      return CURLE_COULDNT_CONNECT;
    }
    gss_release_buffer(&gss_status, &gss_recv_token);

    if(gss_w_token.length != 1) {
      failf(data, "Invalid GSS-API encryption response length (%d).",
            gss_w_token.length);
      gss_release_buffer(&gss_status, &gss_w_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    memcpy(socksreq,gss_w_token.value,gss_w_token.length);
    gss_release_buffer(&gss_status, &gss_w_token);
  }
  else {
    if(gss_recv_token.length != 1) {
      failf(data, "Invalid GSS-API encryption response length (%d).",
            gss_recv_token.length);
      gss_release_buffer(&gss_status, &gss_recv_token);
      gss_delete_sec_context(&gss_status, &gss_context, NULL);
      return CURLE_COULDNT_CONNECT;
    }

    memcpy(socksreq,gss_recv_token.value,gss_recv_token.length);
    gss_release_buffer(&gss_status, &gss_recv_token);
  }

  infof(data, "SOCKS5 access with%s protection granted.\n",
        (socksreq[0]==0)?"out GSS-API data":
        ((socksreq[0]==1)?" GSS-API integrity":" GSS-API confidentiality"));

  conn->socks5_gssapi_enctype = socksreq[0];
  if(socksreq[0] == 0)
    gss_delete_sec_context(&gss_status, &gss_context, NULL);

  return CURLE_OK;
}
#endif

#endif /* CURL_DISABLE_PROXY */