lib/socks_gssapi.c

   1 /***************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * Copyright (C) 2009, 2011, Markus Moeller, <markus_moeller@compuserve.com>
   9  * Copyright (C) 2012 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
  10  *
  11  * This software is licensed as described in the file COPYING, which
  12  * you should have received as part of this distribution. The terms
  13  * are also available at http://curl.haxx.se/docs/copyright.html.
  14  *
  15  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  16  * copies of the Software, and permit persons to whom the Software is
  17  * furnished to do so, under the terms of the COPYING file.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ***************************************************************************/
  23
  24 #include "curl_setup.h"
  25
  26 #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_PROXY)
  27
  28 #include "curl_gssapi.h"
  29 #include "urldata.h"
  30 #include "sendf.h"
  31 #include "connect.h"
  32 #include "timeval.h"
  33 #include "socks.h"
  34 #include "warnless.h"
  35 #include "curl_printf.h"
  36 #include "curl_memory.h"
  37 /* The last #include file should be: */
  38 #include "memdebug.h"
  39
  40 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
  41
  42 /*
  43  * Helper GSS-API error functions.
  44  */
  45 static int check_gss_err(struct SessionHandle *data,
  46                          OM_uint32 major_status,
  47                          OM_uint32 minor_status,
  48                          const char* function)
  49 {
  50   if(GSS_ERROR(major_status)) {
  51     OM_uint32 maj_stat, min_stat;
  52     OM_uint32 msg_ctx = 0;
  53     gss_buffer_desc status_string;
  54     char buf[1024];
  55     size_t len;
  56
  57     len = 0;
  58     msg_ctx = 0;
  59     while(!msg_ctx) {
  60       /* convert major status code (GSS-API error) to text */
  61       maj_stat = gss_display_status(&min_stat, major_status,
  62                                     GSS_C_GSS_CODE,
  63                                     GSS_C_NULL_OID,
  64                                     &msg_ctx, &status_string);
  65       if(maj_stat == GSS_S_COMPLETE) {
  66         if(sizeof(buf) > len + status_string.length + 1) {
  67           strcpy(buf+len, (char*) status_string.value);
  68           len += status_string.length;
  69         }
  70         gss_release_buffer(&min_stat, &status_string);
  71         break;
  72       }
  73       gss_release_buffer(&min_stat, &status_string);
  74     }
  75     if(sizeof(buf) > len + 3) {
  76       strcpy(buf+len, ".\n");
  77       len += 2;
  78     }
  79     msg_ctx = 0;
  80     while(!msg_ctx) {
  81       /* convert minor status code (underlying routine error) to text */
  82       maj_stat = gss_display_status(&min_stat, minor_status,
  83                                     GSS_C_MECH_CODE,
  84                                     GSS_C_NULL_OID,
  85                                     &msg_ctx, &status_string);
  86       if(maj_stat == GSS_S_COMPLETE) {
  87         if(sizeof(buf) > len + status_string.length)
  88           strcpy(buf+len, (char*) status_string.value);
  89         gss_release_buffer(&min_stat, &status_string);
  90         break;
  91       }
  92       gss_release_buffer(&min_stat, &status_string);
  93     }
  94     failf(data, "GSS-API error: %s failed:\n%s", function, buf);
  95     return 1;
  96   }
  97
  98   return 0;
  99 }
 100
 101 CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
 102                                       struct connectdata *conn)
 103 {
 104   struct SessionHandle *data = conn->data;
 105   curl_socket_t sock = conn->sock[sockindex];
 106   CURLcode code;
 107   ssize_t actualread;
 108   ssize_t written;
 109   int result;
 110   OM_uint32 gss_major_status, gss_minor_status, gss_status;
 111   OM_uint32 gss_ret_flags;
 112   int gss_conf_state, gss_enc;
 113   gss_buffer_desc  service = GSS_C_EMPTY_BUFFER;
 114   gss_buffer_desc  gss_send_token = GSS_C_EMPTY_BUFFER;
 115   gss_buffer_desc  gss_recv_token = GSS_C_EMPTY_BUFFER;
 116   gss_buffer_desc  gss_w_token = GSS_C_EMPTY_BUFFER;
 117   gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
 118   gss_name_t       server = GSS_C_NO_NAME;
 119   gss_name_t       gss_client_name = GSS_C_NO_NAME;
 120   unsigned short   us_length;
 121   char             *user=NULL;
 122   unsigned char socksreq[4]; /* room for GSS-API exchange header only */
 123   char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
 124
 125   /*   GSS-API request looks like
 126    * +----+------+-----+----------------+
 127    * |VER | MTYP | LEN |     TOKEN      |
 128    * +----+------+----------------------+
 129    * | 1  |  1   |  2  | up to 2^16 - 1 |
 130    * +----+------+-----+----------------+
 131    */
 132
 133   /* prepare service name */
 134   if(strchr(serviceptr, '/')) {
 135     service.value = malloc(strlen(serviceptr));
 136     if(!service.value)
 137       return CURLE_OUT_OF_MEMORY;
 138     service.length = strlen(serviceptr);
 139     memcpy(service.value, serviceptr, service.length);
 140
 141     gss_major_status = gss_import_name(&gss_minor_status, &service,
 142                                        (gss_OID) GSS_C_NULL_OID, &server);
 143   }
 144   else {
 145     service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
 146     if(!service.value)
 147       return CURLE_OUT_OF_MEMORY;
 148     service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
 149     snprintf(service.value, service.length+1, "%s@%s",
 150              serviceptr, conn->proxy.name);
 151
 152     gss_major_status = gss_import_name(&gss_minor_status, &service,
 153                                        GSS_C_NT_HOSTBASED_SERVICE, &server);
 154   }
 155
 156   gss_release_buffer(&gss_status, &service); /* clear allocated memory */
 157
 158   if(check_gss_err(data, gss_major_status,
 159                    gss_minor_status, "gss_import_name()")) {
 160     failf(data, "Failed to create service name.");
 161     gss_release_name(&gss_status, &server);
 162     return CURLE_COULDNT_CONNECT;
 163   }
 164
 165   /* As long as we need to keep sending some context info, and there's no  */
 166   /* errors, keep sending it...                                            */
 167   for(;;) {
 168     gss_major_status = Curl_gss_init_sec_context(data,
 169                                                  &gss_minor_status,
 170                                                  &gss_context,
 171                                                  server,
 172                                                  &Curl_krb5_mech_oid,
 173                                                  NULL,
 174                                                  gss_token,
 175                                                  &gss_send_token,
 176                                                  TRUE,
 177                                                  &gss_ret_flags);
 178
 179     if(gss_token != GSS_C_NO_BUFFER)
 180       gss_release_buffer(&gss_status, &gss_recv_token);
 181     if(check_gss_err(data, gss_major_status,
 182                      gss_minor_status, "gss_init_sec_context")) {
 183       gss_release_name(&gss_status, &server);
 184       gss_release_buffer(&gss_status, &gss_recv_token);
 185       gss_release_buffer(&gss_status, &gss_send_token);
 186       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 187       failf(data, "Failed to initial GSS-API token.");
 188       return CURLE_COULDNT_CONNECT;
 189     }
 190
 191     if(gss_send_token.length != 0) {
 192       socksreq[0] = 1;    /* GSS-API subnegotiation version */
 193       socksreq[1] = 1;    /* authentication message type */
 194       us_length = htons((short)gss_send_token.length);
 195       memcpy(socksreq+2, &us_length, sizeof(short));
 196
 197       code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 198       if(code || (4 != written)) {
 199         failf(data, "Failed to send GSS-API authentication request.");
 200         gss_release_name(&gss_status, &server);
 201         gss_release_buffer(&gss_status, &gss_recv_token);
 202         gss_release_buffer(&gss_status, &gss_send_token);
 203         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 204         return CURLE_COULDNT_CONNECT;
 205       }
 206
 207       code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
 208                               gss_send_token.length, &written);
 209
 210       if(code || ((ssize_t)gss_send_token.length != written)) {
 211         failf(data, "Failed to send GSS-API authentication token.");
 212         gss_release_name(&gss_status, &server);
 213         gss_release_buffer(&gss_status, &gss_recv_token);
 214         gss_release_buffer(&gss_status, &gss_send_token);
 215         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 216         return CURLE_COULDNT_CONNECT;
 217       }
 218
 219     }
 220
 221     gss_release_buffer(&gss_status, &gss_send_token);
 222     gss_release_buffer(&gss_status, &gss_recv_token);
 223     if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
 224
 225     /* analyse response */
 226
 227     /*   GSS-API response looks like
 228      * +----+------+-----+----------------+
 229      * |VER | MTYP | LEN |     TOKEN      |
 230      * +----+------+----------------------+
 231      * | 1  |  1   |  2  | up to 2^16 - 1 |
 232      * +----+------+-----+----------------+
 233      */
 234
 235     result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 236     if(result || (actualread != 4)) {
 237       failf(data, "Failed to receive GSS-API authentication response.");
 238       gss_release_name(&gss_status, &server);
 239       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 240       return CURLE_COULDNT_CONNECT;
 241     }
 242
 243     /* ignore the first (VER) byte */
 244     if(socksreq[1] == 255) { /* status / message type */
 245       failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 246             socksreq[0], socksreq[1]);
 247       gss_release_name(&gss_status, &server);
 248       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 249       return CURLE_COULDNT_CONNECT;
 250     }
 251
 252     if(socksreq[1] != 1) { /* status / messgae type */
 253       failf(data, "Invalid GSS-API authentication response type (%d %d).",
 254             socksreq[0], socksreq[1]);
 255       gss_release_name(&gss_status, &server);
 256       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 257       return CURLE_COULDNT_CONNECT;
 258     }
 259
 260     memcpy(&us_length, socksreq+2, sizeof(short));
 261     us_length = ntohs(us_length);
 262
 263     gss_recv_token.length=us_length;
 264     gss_recv_token.value=malloc(us_length);
 265     if(!gss_recv_token.value) {
 266       failf(data,
 267             "Could not allocate memory for GSS-API authentication "
 268             "response token.");
 269       gss_release_name(&gss_status, &server);
 270       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 271       return CURLE_OUT_OF_MEMORY;
 272     }
 273
 274     result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 275                               gss_recv_token.length, &actualread);
 276
 277     if(result || (actualread != us_length)) {
 278       failf(data, "Failed to receive GSS-API authentication token.");
 279       gss_release_name(&gss_status, &server);
 280       gss_release_buffer(&gss_status, &gss_recv_token);
 281       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 282       return CURLE_COULDNT_CONNECT;
 283     }
 284
 285     gss_token = &gss_recv_token;
 286   }
 287
 288   gss_release_name(&gss_status, &server);
 289
 290   /* Everything is good so far, user was authenticated! */
 291   gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
 292                                           &gss_client_name, NULL, NULL, NULL,
 293                                           NULL, NULL, NULL);
 294   if(check_gss_err(data, gss_major_status,
 295                    gss_minor_status, "gss_inquire_context")) {
 296     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 297     gss_release_name(&gss_status, &gss_client_name);
 298     failf(data, "Failed to determine user name.");
 299     return CURLE_COULDNT_CONNECT;
 300   }
 301   gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
 302                                       &gss_send_token, NULL);
 303   if(check_gss_err(data, gss_major_status,
 304                    gss_minor_status, "gss_display_name")) {
 305     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 306     gss_release_name(&gss_status, &gss_client_name);
 307     gss_release_buffer(&gss_status, &gss_send_token);
 308     failf(data, "Failed to determine user name.");
 309     return CURLE_COULDNT_CONNECT;
 310   }
 311   user=malloc(gss_send_token.length+1);
 312   if(!user) {
 313     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 314     gss_release_name(&gss_status, &gss_client_name);
 315     gss_release_buffer(&gss_status, &gss_send_token);
 316     return CURLE_OUT_OF_MEMORY;
 317   }
 318
 319   memcpy(user, gss_send_token.value, gss_send_token.length);
 320   user[gss_send_token.length] = '\0';
 321   gss_release_name(&gss_status, &gss_client_name);
 322   gss_release_buffer(&gss_status, &gss_send_token);
 323   infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
 324   free(user);
 325   user=NULL;
 326
 327   /* Do encryption */
 328   socksreq[0] = 1;    /* GSS-API subnegotiation version */
 329   socksreq[1] = 2;    /* encryption message type */
 330
 331   gss_enc = 0; /* no data protection */
 332   /* do confidentiality protection if supported */
 333   if(gss_ret_flags & GSS_C_CONF_FLAG)
 334     gss_enc = 2;
 335   /* else do integrity protection */
 336   else if(gss_ret_flags & GSS_C_INTEG_FLAG)
 337     gss_enc = 1;
 338
 339   infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
 340         (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
 341   /* force for the moment to no data protection */
 342   gss_enc = 0;
 343   /*
 344    * Sending the encryption type in clear seems wrong. It should be
 345    * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
 346    * The NEC reference implementations on which this is based is
 347    * therefore at fault
 348    *
 349    *  +------+------+------+.......................+
 350    *  + ver  | mtyp | len  |   token               |
 351    *  +------+------+------+.......................+
 352    *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
 353    *  +------+------+------+.......................+
 354    *
 355    *   Where:
 356    *
 357    *  - "ver" is the protocol version number, here 1 to represent the
 358    *    first version of the SOCKS/GSS-API protocol
 359    *
 360    *  - "mtyp" is the message type, here 2 to represent a protection
 361    *    -level negotiation message
 362    *
 363    *  - "len" is the length of the "token" field in octets
 364    *
 365    *  - "token" is the GSS-API encapsulated protection level
 366    *
 367    * The token is produced by encapsulating an octet containing the
 368    * required protection level using gss_seal()/gss_wrap() with conf_req
 369    * set to FALSE.  The token is verified using gss_unseal()/
 370    * gss_unwrap().
 371    *
 372    */
 373   if(data->set.socks5_gssapi_nec) {
 374     us_length = htons((short)1);
 375     memcpy(socksreq+2, &us_length, sizeof(short));
 376   }
 377   else {
 378     gss_send_token.length = 1;
 379     gss_send_token.value = malloc(1);
 380     if(!gss_send_token.value) {
 381       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 382       return CURLE_OUT_OF_MEMORY;
 383     }
 384     memcpy(gss_send_token.value, &gss_enc, 1);
 385
 386     gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
 387                                 GSS_C_QOP_DEFAULT, &gss_send_token,
 388                                 &gss_conf_state, &gss_w_token);
 389
 390     if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
 391       gss_release_buffer(&gss_status, &gss_send_token);
 392       gss_release_buffer(&gss_status, &gss_w_token);
 393       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 394       failf(data, "Failed to wrap GSS-API encryption value into token.");
 395       return CURLE_COULDNT_CONNECT;
 396     }
 397     gss_release_buffer(&gss_status, &gss_send_token);
 398
 399     us_length = htons((short)gss_w_token.length);
 400     memcpy(socksreq+2, &us_length, sizeof(short));
 401   }
 402
 403   code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 404   if(code  || (4 != written)) {
 405     failf(data, "Failed to send GSS-API encryption request.");
 406     gss_release_buffer(&gss_status, &gss_w_token);
 407     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 408     return CURLE_COULDNT_CONNECT;
 409   }
 410
 411   if(data->set.socks5_gssapi_nec) {
 412     memcpy(socksreq, &gss_enc, 1);
 413     code = Curl_write_plain(conn, sock, socksreq, 1, &written);
 414     if(code || ( 1 != written)) {
 415       failf(data, "Failed to send GSS-API encryption type.");
 416       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 417       return CURLE_COULDNT_CONNECT;
 418     }
 419   }
 420   else {
 421     code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
 422                             gss_w_token.length, &written);
 423     if(code || ((ssize_t)gss_w_token.length != written)) {
 424       failf(data, "Failed to send GSS-API encryption type.");
 425       gss_release_buffer(&gss_status, &gss_w_token);
 426       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 427       return CURLE_COULDNT_CONNECT;
 428     }
 429     gss_release_buffer(&gss_status, &gss_w_token);
 430   }
 431
 432   result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 433   if(result || (actualread != 4)) {
 434     failf(data, "Failed to receive GSS-API encryption response.");
 435     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 436     return CURLE_COULDNT_CONNECT;
 437   }
 438
 439   /* ignore the first (VER) byte */
 440   if(socksreq[1] == 255) { /* status / message type */
 441     failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 442           socksreq[0], socksreq[1]);
 443     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 444     return CURLE_COULDNT_CONNECT;
 445   }
 446
 447   if(socksreq[1] != 2) { /* status / messgae type */
 448     failf(data, "Invalid GSS-API encryption response type (%d %d).",
 449           socksreq[0], socksreq[1]);
 450     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 451     return CURLE_COULDNT_CONNECT;
 452   }
 453
 454   memcpy(&us_length, socksreq+2, sizeof(short));
 455   us_length = ntohs(us_length);
 456
 457   gss_recv_token.length= us_length;
 458   gss_recv_token.value=malloc(gss_recv_token.length);
 459   if(!gss_recv_token.value) {
 460     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 461     return CURLE_OUT_OF_MEMORY;
 462   }
 463   result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 464                             gss_recv_token.length, &actualread);
 465
 466   if(result || (actualread != us_length)) {
 467     failf(data, "Failed to receive GSS-API encryptrion type.");
 468     gss_release_buffer(&gss_status, &gss_recv_token);
 469     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 470     return CURLE_COULDNT_CONNECT;
 471   }
 472
 473   if(!data->set.socks5_gssapi_nec) {
 474     gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
 475                                   &gss_recv_token, &gss_w_token,
 476                                   0, GSS_C_QOP_DEFAULT);
 477
 478     if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
 479       gss_release_buffer(&gss_status, &gss_recv_token);
 480       gss_release_buffer(&gss_status, &gss_w_token);
 481       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 482       failf(data, "Failed to unwrap GSS-API encryption value into token.");
 483       return CURLE_COULDNT_CONNECT;
 484     }
 485     gss_release_buffer(&gss_status, &gss_recv_token);
 486
 487     if(gss_w_token.length != 1) {
 488       failf(data, "Invalid GSS-API encryption response length (%d).",
 489             gss_w_token.length);
 490       gss_release_buffer(&gss_status, &gss_w_token);
 491       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 492       return CURLE_COULDNT_CONNECT;
 493     }
 494
 495     memcpy(socksreq, gss_w_token.value, gss_w_token.length);
 496     gss_release_buffer(&gss_status, &gss_w_token);
 497   }
 498   else {
 499     if(gss_recv_token.length != 1) {
 500       failf(data, "Invalid GSS-API encryption response length (%d).",
 501             gss_recv_token.length);
 502       gss_release_buffer(&gss_status, &gss_recv_token);
 503       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 504       return CURLE_COULDNT_CONNECT;
 505     }
 506
 507     memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
 508     gss_release_buffer(&gss_status, &gss_recv_token);
 509   }
 510
 511   infof(data, "SOCKS5 access with%s protection granted.\n",
 512         (socksreq[0]==0)?"out GSS-API data":
 513         ((socksreq[0]==1)?" GSS-API integrity":" GSS-API confidentiality"));
 514
 515   conn->socks5_gssapi_enctype = socksreq[0];
 516   if(socksreq[0] == 0)
 517     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 518
 519   return CURLE_OK;
 520 }
 521
 522 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */