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
  36 #define _MPRINTF_REPLACE /* use our functions only */
  37 #include <curl/mprintf.h>
  38
  39 #include "curl_memory.h"
  40 /* The last #include file should be: */
  41 #include "memdebug.h"
  42
  43 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
  44
  45 /*
  46  * Helper GSS-API error functions.
  47  */
  48 static int check_gss_err(struct SessionHandle *data,
  49                          OM_uint32 major_status,
  50                          OM_uint32 minor_status,
  51                          const char* function)
  52 {
  53   if(GSS_ERROR(major_status)) {
  54     OM_uint32 maj_stat,min_stat;
  55     OM_uint32 msg_ctx = 0;
  56     gss_buffer_desc status_string;
  57     char buf[1024];
  58     size_t len;
  59
  60     len = 0;
  61     msg_ctx = 0;
  62     while(!msg_ctx) {
  63       /* convert major status code (GSS-API error) to text */
  64       maj_stat = gss_display_status(&min_stat, major_status,
  65                                     GSS_C_GSS_CODE,
  66                                     GSS_C_NULL_OID,
  67                                     &msg_ctx, &status_string);
  68       if(maj_stat == GSS_S_COMPLETE) {
  69         if(sizeof(buf) > len + status_string.length + 1) {
  70           strcpy(buf+len, (char*) status_string.value);
  71           len += status_string.length;
  72         }
  73         gss_release_buffer(&min_stat, &status_string);
  74         break;
  75       }
  76       gss_release_buffer(&min_stat, &status_string);
  77     }
  78     if(sizeof(buf) > len + 3) {
  79       strcpy(buf+len, ".\n");
  80       len += 2;
  81     }
  82     msg_ctx = 0;
  83     while(!msg_ctx) {
  84       /* convert minor status code (underlying routine error) to text */
  85       maj_stat = gss_display_status(&min_stat, minor_status,
  86                                     GSS_C_MECH_CODE,
  87                                     GSS_C_NULL_OID,
  88                                     &msg_ctx, &status_string);
  89       if(maj_stat == GSS_S_COMPLETE) {
  90         if(sizeof(buf) > len + status_string.length)
  91           strcpy(buf+len, (char*) status_string.value);
  92         gss_release_buffer(&min_stat, &status_string);
  93         break;
  94       }
  95       gss_release_buffer(&min_stat, &status_string);
  96     }
  97     failf(data, "GSS-API error: %s failed:\n%s", function, buf);
  98     return(1);
  99   }
 100
 101   return(0);
 102 }
 103
 104 CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
 105                                       struct connectdata *conn)
 106 {
 107   struct SessionHandle *data = conn->data;
 108   curl_socket_t sock = conn->sock[sockindex];
 109   CURLcode code;
 110   ssize_t actualread;
 111   ssize_t written;
 112   int result;
 113   OM_uint32 gss_major_status, gss_minor_status, gss_status;
 114   OM_uint32 gss_ret_flags;
 115   int gss_conf_state, gss_enc;
 116   gss_buffer_desc  service = GSS_C_EMPTY_BUFFER;
 117   gss_buffer_desc  gss_send_token = GSS_C_EMPTY_BUFFER;
 118   gss_buffer_desc  gss_recv_token = GSS_C_EMPTY_BUFFER;
 119   gss_buffer_desc  gss_w_token = GSS_C_EMPTY_BUFFER;
 120   gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
 121   gss_name_t       server = GSS_C_NO_NAME;
 122   gss_name_t       gss_client_name = GSS_C_NO_NAME;
 123   unsigned short   us_length;
 124   char             *user=NULL;
 125   unsigned char socksreq[4]; /* room for GSS-API exchange header only */
 126   char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
 127
 128   /*   GSS-API request looks like
 129    * +----+------+-----+----------------+
 130    * |VER | MTYP | LEN |     TOKEN      |
 131    * +----+------+----------------------+
 132    * | 1  |  1   |  2  | up to 2^16 - 1 |
 133    * +----+------+-----+----------------+
 134    */
 135
 136   /* prepare service name */
 137   if(strchr(serviceptr,'/')) {
 138     service.value = malloc(strlen(serviceptr));
 139     if(!service.value)
 140       return CURLE_OUT_OF_MEMORY;
 141     service.length = strlen(serviceptr);
 142     memcpy(service.value, serviceptr, service.length);
 143
 144     gss_major_status = gss_import_name(&gss_minor_status, &service,
 145                                        (gss_OID) GSS_C_NULL_OID, &server);
 146   }
 147   else {
 148     service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
 149     if(!service.value)
 150       return CURLE_OUT_OF_MEMORY;
 151     service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
 152     snprintf(service.value, service.length+1, "%s@%s",
 153              serviceptr, conn->proxy.name);
 154
 155     gss_major_status = gss_import_name(&gss_minor_status, &service,
 156                                        GSS_C_NT_HOSTBASED_SERVICE, &server);
 157   }
 158
 159   gss_release_buffer(&gss_status, &service); /* clear allocated memory */
 160
 161   if(check_gss_err(data,gss_major_status,
 162                    gss_minor_status,"gss_import_name()")) {
 163     failf(data, "Failed to create service name.");
 164     gss_release_name(&gss_status, &server);
 165     return CURLE_COULDNT_CONNECT;
 166   }
 167
 168   /* As long as we need to keep sending some context info, and there's no  */
 169   /* errors, keep sending it...                                            */
 170   for(;;) {
 171     gss_major_status = Curl_gss_init_sec_context(data,
 172                                                  &gss_minor_status,
 173                                                  &gss_context,
 174                                                  server,
 175                                                  &Curl_krb5_mech_oid,
 176                                                  NULL,
 177                                                  gss_token,
 178                                                  &gss_send_token,
 179                                                  TRUE,
 180                                                  &gss_ret_flags);
 181
 182     if(gss_token != GSS_C_NO_BUFFER)
 183       gss_release_buffer(&gss_status, &gss_recv_token);
 184     if(check_gss_err(data,gss_major_status,
 185                      gss_minor_status,"gss_init_sec_context")) {
 186       gss_release_name(&gss_status, &server);
 187       gss_release_buffer(&gss_status, &gss_recv_token);
 188       gss_release_buffer(&gss_status, &gss_send_token);
 189       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 190       failf(data, "Failed to initial GSS-API token.");
 191       return CURLE_COULDNT_CONNECT;
 192     }
 193
 194     if(gss_send_token.length != 0) {
 195       socksreq[0] = 1;    /* GSS-API subnegotiation version */
 196       socksreq[1] = 1;    /* authentication message type */
 197       us_length = htons((short)gss_send_token.length);
 198       memcpy(socksreq+2,&us_length,sizeof(short));
 199
 200       code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 201       if(code || (4 != written)) {
 202         failf(data, "Failed to send GSS-API authentication request.");
 203         gss_release_name(&gss_status, &server);
 204         gss_release_buffer(&gss_status, &gss_recv_token);
 205         gss_release_buffer(&gss_status, &gss_send_token);
 206         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 207         return CURLE_COULDNT_CONNECT;
 208       }
 209
 210       code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
 211                               gss_send_token.length, &written);
 212
 213       if(code || ((ssize_t)gss_send_token.length != written)) {
 214         failf(data, "Failed to send GSS-API authentication token.");
 215         gss_release_name(&gss_status, &server);
 216         gss_release_buffer(&gss_status, &gss_recv_token);
 217         gss_release_buffer(&gss_status, &gss_send_token);
 218         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 219         return CURLE_COULDNT_CONNECT;
 220       }
 221
 222     }
 223
 224     gss_release_buffer(&gss_status, &gss_send_token);
 225     gss_release_buffer(&gss_status, &gss_recv_token);
 226     if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
 227
 228     /* analyse response */
 229
 230     /*   GSS-API response looks like
 231      * +----+------+-----+----------------+
 232      * |VER | MTYP | LEN |     TOKEN      |
 233      * +----+------+----------------------+
 234      * | 1  |  1   |  2  | up to 2^16 - 1 |
 235      * +----+------+-----+----------------+
 236      */
 237
 238     result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 239     if(result || (actualread != 4)) {
 240       failf(data, "Failed to receive GSS-API authentication response.");
 241       gss_release_name(&gss_status, &server);
 242       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 243       return CURLE_COULDNT_CONNECT;
 244     }
 245
 246     /* ignore the first (VER) byte */
 247     if(socksreq[1] == 255) { /* status / message type */
 248       failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 249             socksreq[0], socksreq[1]);
 250       gss_release_name(&gss_status, &server);
 251       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 252       return CURLE_COULDNT_CONNECT;
 253     }
 254
 255     if(socksreq[1] != 1) { /* status / messgae type */
 256       failf(data, "Invalid GSS-API authentication response type (%d %d).",
 257             socksreq[0], socksreq[1]);
 258       gss_release_name(&gss_status, &server);
 259       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 260       return CURLE_COULDNT_CONNECT;
 261     }
 262
 263     memcpy(&us_length, socksreq+2, sizeof(short));
 264     us_length = ntohs(us_length);
 265
 266     gss_recv_token.length=us_length;
 267     gss_recv_token.value=malloc(us_length);
 268     if(!gss_recv_token.value) {
 269       failf(data,
 270             "Could not allocate memory for GSS-API authentication "
 271             "response token.");
 272       gss_release_name(&gss_status, &server);
 273       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 274       return CURLE_OUT_OF_MEMORY;
 275     }
 276
 277     result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 278                               gss_recv_token.length, &actualread);
 279
 280     if(result || (actualread != us_length)) {
 281       failf(data, "Failed to receive GSS-API authentication token.");
 282       gss_release_name(&gss_status, &server);
 283       gss_release_buffer(&gss_status, &gss_recv_token);
 284       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 285       return CURLE_COULDNT_CONNECT;
 286     }
 287
 288     gss_token = &gss_recv_token;
 289   }
 290
 291   gss_release_name(&gss_status, &server);
 292
 293   /* Everything is good so far, user was authenticated! */
 294   gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
 295                                           &gss_client_name, NULL, NULL, NULL,
 296                                           NULL, NULL, NULL);
 297   if(check_gss_err(data,gss_major_status,
 298                    gss_minor_status,"gss_inquire_context")) {
 299     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 300     gss_release_name(&gss_status, &gss_client_name);
 301     failf(data, "Failed to determine user name.");
 302     return CURLE_COULDNT_CONNECT;
 303   }
 304   gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
 305                                       &gss_send_token, NULL);
 306   if(check_gss_err(data,gss_major_status,
 307                    gss_minor_status,"gss_display_name")) {
 308     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 309     gss_release_name(&gss_status, &gss_client_name);
 310     gss_release_buffer(&gss_status, &gss_send_token);
 311     failf(data, "Failed to determine user name.");
 312     return CURLE_COULDNT_CONNECT;
 313   }
 314   user=malloc(gss_send_token.length+1);
 315   if(!user) {
 316     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 317     gss_release_name(&gss_status, &gss_client_name);
 318     gss_release_buffer(&gss_status, &gss_send_token);
 319     return CURLE_OUT_OF_MEMORY;
 320   }
 321
 322   memcpy(user, gss_send_token.value, gss_send_token.length);
 323   user[gss_send_token.length] = '\0';
 324   gss_release_name(&gss_status, &gss_client_name);
 325   gss_release_buffer(&gss_status, &gss_send_token);
 326   infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
 327   free(user);
 328   user=NULL;
 329
 330   /* Do encryption */
 331   socksreq[0] = 1;    /* GSS-API subnegotiation version */
 332   socksreq[1] = 2;    /* encryption message type */
 333
 334   gss_enc = 0; /* no data protection */
 335   /* do confidentiality protection if supported */
 336   if(gss_ret_flags & GSS_C_CONF_FLAG)
 337     gss_enc = 2;
 338   /* else do integrity protection */
 339   else if(gss_ret_flags & GSS_C_INTEG_FLAG)
 340     gss_enc = 1;
 341
 342   infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
 343         (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
 344   /* force for the moment to no data protection */
 345   gss_enc = 0;
 346   /*
 347    * Sending the encryption type in clear seems wrong. It should be
 348    * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
 349    * The NEC reference implementations on which this is based is
 350    * therefore at fault
 351    *
 352    *  +------+------+------+.......................+
 353    *  + ver  | mtyp | len  |   token               |
 354    *  +------+------+------+.......................+
 355    *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
 356    *  +------+------+------+.......................+
 357    *
 358    *   Where:
 359    *
 360    *  - "ver" is the protocol version number, here 1 to represent the
 361    *    first version of the SOCKS/GSS-API protocol
 362    *
 363    *  - "mtyp" is the message type, here 2 to represent a protection
 364    *    -level negotiation message
 365    *
 366    *  - "len" is the length of the "token" field in octets
 367    *
 368    *  - "token" is the GSS-API encapsulated protection level
 369    *
 370    * The token is produced by encapsulating an octet containing the
 371    * required protection level using gss_seal()/gss_wrap() with conf_req
 372    * set to FALSE.  The token is verified using gss_unseal()/
 373    * gss_unwrap().
 374    *
 375    */
 376   if(data->set.socks5_gssapi_nec) {
 377     us_length = htons((short)1);
 378     memcpy(socksreq+2,&us_length,sizeof(short));
 379   }
 380   else {
 381     gss_send_token.length = 1;
 382     gss_send_token.value = malloc(1);
 383     if(!gss_send_token.value) {
 384       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 385       return CURLE_OUT_OF_MEMORY;
 386     }
 387     memcpy(gss_send_token.value, &gss_enc, 1);
 388
 389     gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
 390                                 GSS_C_QOP_DEFAULT, &gss_send_token,
 391                                 &gss_conf_state, &gss_w_token);
 392
 393     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_wrap")) {
 394       gss_release_buffer(&gss_status, &gss_send_token);
 395       gss_release_buffer(&gss_status, &gss_w_token);
 396       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 397       failf(data, "Failed to wrap GSS-API encryption value into token.");
 398       return CURLE_COULDNT_CONNECT;
 399     }
 400     gss_release_buffer(&gss_status, &gss_send_token);
 401
 402     us_length = htons((short)gss_w_token.length);
 403     memcpy(socksreq+2,&us_length,sizeof(short));
 404   }
 405
 406   code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 407   if(code  || (4 != written)) {
 408     failf(data, "Failed to send GSS-API encryption request.");
 409     gss_release_buffer(&gss_status, &gss_w_token);
 410     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 411     return CURLE_COULDNT_CONNECT;
 412   }
 413
 414   if(data->set.socks5_gssapi_nec) {
 415     memcpy(socksreq, &gss_enc, 1);
 416     code = Curl_write_plain(conn, sock, socksreq, 1, &written);
 417     if(code || ( 1 != written)) {
 418       failf(data, "Failed to send GSS-API encryption type.");
 419       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 420       return CURLE_COULDNT_CONNECT;
 421     }
 422   }
 423   else {
 424     code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
 425                             gss_w_token.length, &written);
 426     if(code || ((ssize_t)gss_w_token.length != written)) {
 427       failf(data, "Failed to send GSS-API encryption type.");
 428       gss_release_buffer(&gss_status, &gss_w_token);
 429       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 430       return CURLE_COULDNT_CONNECT;
 431     }
 432     gss_release_buffer(&gss_status, &gss_w_token);
 433   }
 434
 435   result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 436   if(result || (actualread != 4)) {
 437     failf(data, "Failed to receive GSS-API encryption response.");
 438     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 439     return CURLE_COULDNT_CONNECT;
 440   }
 441
 442   /* ignore the first (VER) byte */
 443   if(socksreq[1] == 255) { /* status / message type */
 444     failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 445           socksreq[0], socksreq[1]);
 446     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 447     return CURLE_COULDNT_CONNECT;
 448   }
 449
 450   if(socksreq[1] != 2) { /* status / messgae type */
 451     failf(data, "Invalid GSS-API encryption response type (%d %d).",
 452           socksreq[0], socksreq[1]);
 453     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 454     return CURLE_COULDNT_CONNECT;
 455   }
 456
 457   memcpy(&us_length, socksreq+2, sizeof(short));
 458   us_length = ntohs(us_length);
 459
 460   gss_recv_token.length= us_length;
 461   gss_recv_token.value=malloc(gss_recv_token.length);
 462   if(!gss_recv_token.value) {
 463     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 464     return CURLE_OUT_OF_MEMORY;
 465   }
 466   result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 467                             gss_recv_token.length, &actualread);
 468
 469   if(result || (actualread != us_length)) {
 470     failf(data, "Failed to receive GSS-API encryptrion type.");
 471     gss_release_buffer(&gss_status, &gss_recv_token);
 472     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 473     return CURLE_COULDNT_CONNECT;
 474   }
 475
 476   if(!data->set.socks5_gssapi_nec) {
 477     gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
 478                                   &gss_recv_token, &gss_w_token,
 479                                   0, GSS_C_QOP_DEFAULT);
 480
 481     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_unwrap")) {
 482       gss_release_buffer(&gss_status, &gss_recv_token);
 483       gss_release_buffer(&gss_status, &gss_w_token);
 484       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 485       failf(data, "Failed to unwrap GSS-API encryption value into token.");
 486       return CURLE_COULDNT_CONNECT;
 487     }
 488     gss_release_buffer(&gss_status, &gss_recv_token);
 489
 490     if(gss_w_token.length != 1) {
 491       failf(data, "Invalid GSS-API encryption response length (%d).",
 492             gss_w_token.length);
 493       gss_release_buffer(&gss_status, &gss_w_token);
 494       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 495       return CURLE_COULDNT_CONNECT;
 496     }
 497
 498     memcpy(socksreq,gss_w_token.value,gss_w_token.length);
 499     gss_release_buffer(&gss_status, &gss_w_token);
 500   }
 501   else {
 502     if(gss_recv_token.length != 1) {
 503       failf(data, "Invalid GSS-API encryption response length (%d).",
 504             gss_recv_token.length);
 505       gss_release_buffer(&gss_status, &gss_recv_token);
 506       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 507       return CURLE_COULDNT_CONNECT;
 508     }
 509
 510     memcpy(socksreq,gss_recv_token.value,gss_recv_token.length);
 511     gss_release_buffer(&gss_status, &gss_recv_token);
 512   }
 513
 514   infof(data, "SOCKS5 access with%s protection granted.\n",
 515         (socksreq[0]==0)?"out GSS-API data":
 516         ((socksreq[0]==1)?" GSS-API integrity":" GSS-API confidentiality"));
 517
 518   conn->socks5_gssapi_enctype = socksreq[0];
 519   if(socksreq[0] == 0)
 520     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 521
 522   return CURLE_OK;
 523 }
 524
 525 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */