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, 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 #ifndef CURL_DISABLE_PROXY
  27
  28 #ifdef HAVE_GSSAPI
  29 #ifdef HAVE_OLD_GSSMIT
  30 #define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
  31 #define NCOMPAT 1
  32 #endif
  33 #ifndef gss_nt_service_name
  34 #define gss_nt_service_name GSS_C_NT_HOSTBASED_SERVICE
  35 #endif
  36
  37 #include "curl_gssapi.h"
  38 #include "urldata.h"
  39 #include "sendf.h"
  40 #include "connect.h"
  41 #include "timeval.h"
  42 #include "socks.h"
  43 #include "warnless.h"
  44
  45 #define _MPRINTF_REPLACE /* use our functions only */
  46 #include <curl/mprintf.h>
  47
  48 #include "curl_memory.h"
  49 /* The last #include file should be: */
  50 #include "memdebug.h"
  51
  52 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
  53
  54 /*
  55  * Helper gssapi error functions.
  56  */
  57 static int check_gss_err(struct SessionHandle *data,
  58                          OM_uint32 major_status,
  59                          OM_uint32 minor_status,
  60                          const char* function)
  61 {
  62   if(GSS_ERROR(major_status)) {
  63     OM_uint32 maj_stat,min_stat;
  64     OM_uint32 msg_ctx = 0;
  65     gss_buffer_desc status_string;
  66     char buf[1024];
  67     size_t len;
  68
  69     len = 0;
  70     msg_ctx = 0;
  71     while(!msg_ctx) {
  72       /* convert major status code (GSS-API error) to text */
  73       maj_stat = gss_display_status(&min_stat, major_status,
  74                                     GSS_C_GSS_CODE,
  75                                     GSS_C_NULL_OID,
  76                                     &msg_ctx, &status_string);
  77       if(maj_stat == GSS_S_COMPLETE) {
  78         if(sizeof(buf) > len + status_string.length + 1) {
  79           strcpy(buf+len, (char*) status_string.value);
  80           len += status_string.length;
  81         }
  82         gss_release_buffer(&min_stat, &status_string);
  83         break;
  84       }
  85       gss_release_buffer(&min_stat, &status_string);
  86     }
  87     if(sizeof(buf) > len + 3) {
  88       strcpy(buf+len, ".\n");
  89       len += 2;
  90     }
  91     msg_ctx = 0;
  92     while(!msg_ctx) {
  93       /* convert minor status code (underlying routine error) to text */
  94       maj_stat = gss_display_status(&min_stat, minor_status,
  95                                     GSS_C_MECH_CODE,
  96                                     GSS_C_NULL_OID,
  97                                     &msg_ctx, &status_string);
  98       if(maj_stat == GSS_S_COMPLETE) {
  99         if(sizeof(buf) > len + status_string.length)
 100           strcpy(buf+len, (char*) status_string.value);
 101         gss_release_buffer(&min_stat, &status_string);
 102         break;
 103       }
 104       gss_release_buffer(&min_stat, &status_string);
 105     }
 106     failf(data, "GSSAPI error: %s failed:\n%s", function, buf);
 107     return(1);
 108   }
 109
 110   return(0);
 111 }
 112
 113 CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
 114                                       struct connectdata *conn)
 115 {
 116   struct SessionHandle *data = conn->data;
 117   curl_socket_t sock = conn->sock[sockindex];
 118   CURLcode code;
 119   ssize_t actualread;
 120   ssize_t written;
 121   int result;
 122   OM_uint32 gss_major_status, gss_minor_status, gss_status;
 123   OM_uint32 gss_ret_flags;
 124   int gss_conf_state, gss_enc;
 125   gss_buffer_desc  service = GSS_C_EMPTY_BUFFER;
 126   gss_buffer_desc  gss_send_token = GSS_C_EMPTY_BUFFER;
 127   gss_buffer_desc  gss_recv_token = GSS_C_EMPTY_BUFFER;
 128   gss_buffer_desc  gss_w_token = GSS_C_EMPTY_BUFFER;
 129   gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
 130   gss_name_t       server = GSS_C_NO_NAME;
 131   gss_name_t       gss_client_name = GSS_C_NO_NAME;
 132   unsigned short   us_length;
 133   char             *user=NULL;
 134   unsigned char socksreq[4]; /* room for gssapi exchange header only */
 135   char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
 136
 137   /*   GSSAPI request looks like
 138    * +----+------+-----+----------------+
 139    * |VER | MTYP | LEN |     TOKEN      |
 140    * +----+------+----------------------+
 141    * | 1  |  1   |  2  | up to 2^16 - 1 |
 142    * +----+------+-----+----------------+
 143    */
 144
 145   /* prepare service name */
 146   if(strchr(serviceptr,'/')) {
 147     service.value = malloc(strlen(serviceptr));
 148     if(!service.value)
 149       return CURLE_OUT_OF_MEMORY;
 150     service.length = strlen(serviceptr);
 151     memcpy(service.value, serviceptr, service.length);
 152
 153     gss_major_status = gss_import_name(&gss_minor_status, &service,
 154                                        (gss_OID) GSS_C_NULL_OID, &server);
 155   }
 156   else {
 157     service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
 158     if(!service.value)
 159       return CURLE_OUT_OF_MEMORY;
 160     service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
 161     snprintf(service.value, service.length+1, "%s@%s",
 162              serviceptr, conn->proxy.name);
 163
 164     gss_major_status = gss_import_name(&gss_minor_status, &service,
 165                                        gss_nt_service_name, &server);
 166   }
 167
 168   gss_release_buffer(&gss_status, &service); /* clear allocated memory */
 169
 170   if(check_gss_err(data,gss_major_status,
 171                    gss_minor_status,"gss_import_name()")) {
 172     failf(data, "Failed to create service name.");
 173     gss_release_name(&gss_status, &server);
 174     return CURLE_COULDNT_CONNECT;
 175   }
 176
 177   /* As long as we need to keep sending some context info, and there's no  */
 178   /* errors, keep sending it...                                            */
 179   for(;;) {
 180     gss_major_status = Curl_gss_init_sec_context(data,
 181                                                  &gss_minor_status,
 182                                                  &gss_context,
 183                                                  server,
 184                                                  NULL,
 185                                                  gss_token,
 186                                                  &gss_send_token,
 187                                                  &gss_ret_flags);
 188
 189     if(gss_token != GSS_C_NO_BUFFER)
 190       gss_release_buffer(&gss_status, &gss_recv_token);
 191     if(check_gss_err(data,gss_major_status,
 192                      gss_minor_status,"gss_init_sec_context")) {
 193       gss_release_name(&gss_status, &server);
 194       gss_release_buffer(&gss_status, &gss_recv_token);
 195       gss_release_buffer(&gss_status, &gss_send_token);
 196       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 197       failf(data, "Failed to initial GSSAPI token.");
 198       return CURLE_COULDNT_CONNECT;
 199     }
 200
 201     if(gss_send_token.length != 0) {
 202       socksreq[0] = 1;    /* gssapi subnegotiation version */
 203       socksreq[1] = 1;    /* authentication message type */
 204       us_length = htons((short)gss_send_token.length);
 205       memcpy(socksreq+2,&us_length,sizeof(short));
 206
 207       code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 208       if((code != CURLE_OK) || (4 != written)) {
 209         failf(data, "Failed to send GSSAPI authentication request.");
 210         gss_release_name(&gss_status, &server);
 211         gss_release_buffer(&gss_status, &gss_recv_token);
 212         gss_release_buffer(&gss_status, &gss_send_token);
 213         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 214         return CURLE_COULDNT_CONNECT;
 215       }
 216
 217       code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
 218                               gss_send_token.length, &written);
 219
 220       if((code != CURLE_OK) || ((ssize_t)gss_send_token.length != written)) {
 221         failf(data, "Failed to send GSSAPI authentication token.");
 222         gss_release_name(&gss_status, &server);
 223         gss_release_buffer(&gss_status, &gss_recv_token);
 224         gss_release_buffer(&gss_status, &gss_send_token);
 225         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 226         return CURLE_COULDNT_CONNECT;
 227       }
 228
 229     }
 230
 231     gss_release_buffer(&gss_status, &gss_send_token);
 232     gss_release_buffer(&gss_status, &gss_recv_token);
 233     if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
 234
 235     /* analyse response */
 236
 237     /*   GSSAPI response looks like
 238      * +----+------+-----+----------------+
 239      * |VER | MTYP | LEN |     TOKEN      |
 240      * +----+------+----------------------+
 241      * | 1  |  1   |  2  | up to 2^16 - 1 |
 242      * +----+------+-----+----------------+
 243      */
 244
 245     result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 246     if(result != CURLE_OK || actualread != 4) {
 247       failf(data, "Failed to receive GSSAPI authentication response.");
 248       gss_release_name(&gss_status, &server);
 249       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 250       return CURLE_COULDNT_CONNECT;
 251     }
 252
 253     /* ignore the first (VER) byte */
 254     if(socksreq[1] == 255) { /* status / message type */
 255       failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 256             socksreq[0], socksreq[1]);
 257       gss_release_name(&gss_status, &server);
 258       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 259       return CURLE_COULDNT_CONNECT;
 260     }
 261
 262     if(socksreq[1] != 1) { /* status / messgae type */
 263       failf(data, "Invalid GSSAPI authentication response type (%d %d).",
 264             socksreq[0], socksreq[1]);
 265       gss_release_name(&gss_status, &server);
 266       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 267       return CURLE_COULDNT_CONNECT;
 268     }
 269
 270     memcpy(&us_length, socksreq+2, sizeof(short));
 271     us_length = ntohs(us_length);
 272
 273     gss_recv_token.length=us_length;
 274     gss_recv_token.value=malloc(us_length);
 275     if(!gss_recv_token.value) {
 276       failf(data,
 277             "Could not allocate memory for GSSAPI authentication "
 278             "response token.");
 279       gss_release_name(&gss_status, &server);
 280       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 281       return CURLE_OUT_OF_MEMORY;
 282     }
 283
 284     result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 285                               gss_recv_token.length, &actualread);
 286
 287     if(result != CURLE_OK || actualread != us_length) {
 288       failf(data, "Failed to receive GSSAPI authentication token.");
 289       gss_release_name(&gss_status, &server);
 290       gss_release_buffer(&gss_status, &gss_recv_token);
 291       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 292       return CURLE_COULDNT_CONNECT;
 293     }
 294
 295     gss_token = &gss_recv_token;
 296   }
 297
 298   gss_release_name(&gss_status, &server);
 299
 300   /* Everything is good so far, user was authenticated! */
 301   gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
 302                                           &gss_client_name, NULL, NULL, NULL,
 303                                           NULL, NULL, NULL);
 304   if(check_gss_err(data,gss_major_status,
 305                    gss_minor_status,"gss_inquire_context")) {
 306     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 307     gss_release_name(&gss_status, &gss_client_name);
 308     failf(data, "Failed to determine user name.");
 309     return CURLE_COULDNT_CONNECT;
 310   }
 311   gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
 312                                       &gss_send_token, NULL);
 313   if(check_gss_err(data,gss_major_status,
 314                    gss_minor_status,"gss_display_name")) {
 315     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 316     gss_release_name(&gss_status, &gss_client_name);
 317     gss_release_buffer(&gss_status, &gss_send_token);
 318     failf(data, "Failed to determine user name.");
 319     return CURLE_COULDNT_CONNECT;
 320   }
 321   user=malloc(gss_send_token.length+1);
 322   if(!user) {
 323     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 324     gss_release_name(&gss_status, &gss_client_name);
 325     gss_release_buffer(&gss_status, &gss_send_token);
 326     return CURLE_OUT_OF_MEMORY;
 327   }
 328
 329   memcpy(user, gss_send_token.value, gss_send_token.length);
 330   user[gss_send_token.length] = '\0';
 331   gss_release_name(&gss_status, &gss_client_name);
 332   gss_release_buffer(&gss_status, &gss_send_token);
 333   infof(data, "SOCKS5 server authencticated user %s with gssapi.\n",user);
 334   free(user);
 335   user=NULL;
 336
 337   /* Do encryption */
 338   socksreq[0] = 1;    /* gssapi subnegotiation version */
 339   socksreq[1] = 2;    /* encryption message type */
 340
 341   gss_enc = 0; /* no data protection */
 342   /* do confidentiality protection if supported */
 343   if(gss_ret_flags & GSS_C_CONF_FLAG)
 344     gss_enc = 2;
 345   /* else do integrity protection */
 346   else if(gss_ret_flags & GSS_C_INTEG_FLAG)
 347     gss_enc = 1;
 348
 349   infof(data, "SOCKS5 server supports gssapi %s data protection.\n",
 350         (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
 351   /* force for the moment to no data protection */
 352   gss_enc = 0;
 353   /*
 354    * Sending the encryption type in clear seems wrong. It should be
 355    * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
 356    * The NEC reference implementations on which this is based is
 357    * therefore at fault
 358    *
 359    *  +------+------+------+.......................+
 360    *  + ver  | mtyp | len  |   token               |
 361    *  +------+------+------+.......................+
 362    *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
 363    *  +------+------+------+.......................+
 364    *
 365    *   Where:
 366    *
 367    *  - "ver" is the protocol version number, here 1 to represent the
 368    *    first version of the SOCKS/GSS-API protocol
 369    *
 370    *  - "mtyp" is the message type, here 2 to represent a protection
 371    *    -level negotiation message
 372    *
 373    *  - "len" is the length of the "token" field in octets
 374    *
 375    *  - "token" is the GSS-API encapsulated protection level
 376    *
 377    * The token is produced by encapsulating an octet containing the
 378    * required protection level using gss_seal()/gss_wrap() with conf_req
 379    * set to FALSE.  The token is verified using gss_unseal()/
 380    * gss_unwrap().
 381    *
 382    */
 383   if(data->set.socks5_gssapi_nec) {
 384     us_length = htons((short)1);
 385     memcpy(socksreq+2,&us_length,sizeof(short));
 386   }
 387   else {
 388     gss_send_token.length = 1;
 389     gss_send_token.value = malloc(1);
 390     if(!gss_send_token.value) {
 391       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 392       return CURLE_OUT_OF_MEMORY;
 393     }
 394     memcpy(gss_send_token.value, &gss_enc, 1);
 395
 396     gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
 397                                 GSS_C_QOP_DEFAULT, &gss_send_token,
 398                                 &gss_conf_state, &gss_w_token);
 399
 400     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_wrap")) {
 401       gss_release_buffer(&gss_status, &gss_send_token);
 402       gss_release_buffer(&gss_status, &gss_w_token);
 403       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 404       failf(data, "Failed to wrap GSSAPI encryption value into token.");
 405       return CURLE_COULDNT_CONNECT;
 406     }
 407     gss_release_buffer(&gss_status, &gss_send_token);
 408
 409     us_length = htons((short)gss_w_token.length);
 410     memcpy(socksreq+2,&us_length,sizeof(short));
 411   }
 412
 413   code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 414   if((code != CURLE_OK) || (4 != written)) {
 415     failf(data, "Failed to send GSSAPI encryption request.");
 416     gss_release_buffer(&gss_status, &gss_w_token);
 417     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 418     return CURLE_COULDNT_CONNECT;
 419   }
 420
 421   if(data->set.socks5_gssapi_nec) {
 422     memcpy(socksreq, &gss_enc, 1);
 423     code = Curl_write_plain(conn, sock, socksreq, 1, &written);
 424     if((code != CURLE_OK) || ( 1 != written)) {
 425       failf(data, "Failed to send GSSAPI encryption type.");
 426       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 427       return CURLE_COULDNT_CONNECT;
 428     }
 429   }
 430   else {
 431     code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
 432                             gss_w_token.length, &written);
 433     if((code != CURLE_OK) || ((ssize_t)gss_w_token.length != written)) {
 434       failf(data, "Failed to send GSSAPI encryption type.");
 435       gss_release_buffer(&gss_status, &gss_w_token);
 436       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 437       return CURLE_COULDNT_CONNECT;
 438     }
 439     gss_release_buffer(&gss_status, &gss_w_token);
 440   }
 441
 442   result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 443   if(result != CURLE_OK || actualread != 4) {
 444     failf(data, "Failed to receive GSSAPI encryption response.");
 445     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 446     return CURLE_COULDNT_CONNECT;
 447   }
 448
 449   /* ignore the first (VER) byte */
 450   if(socksreq[1] == 255) { /* status / message type */
 451     failf(data, "User was rejected by the SOCKS5 server (%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   if(socksreq[1] != 2) { /* status / messgae type */
 458     failf(data, "Invalid GSSAPI encryption response type (%d %d).",
 459           socksreq[0], socksreq[1]);
 460     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 461     return CURLE_COULDNT_CONNECT;
 462   }
 463
 464   memcpy(&us_length, socksreq+2, sizeof(short));
 465   us_length = ntohs(us_length);
 466
 467   gss_recv_token.length= us_length;
 468   gss_recv_token.value=malloc(gss_recv_token.length);
 469   if(!gss_recv_token.value) {
 470     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 471     return CURLE_OUT_OF_MEMORY;
 472   }
 473   result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 474                             gss_recv_token.length, &actualread);
 475
 476   if(result != CURLE_OK || actualread != us_length) {
 477     failf(data, "Failed to receive GSSAPI encryptrion type.");
 478     gss_release_buffer(&gss_status, &gss_recv_token);
 479     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 480     return CURLE_COULDNT_CONNECT;
 481   }
 482
 483   if(!data->set.socks5_gssapi_nec) {
 484     gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
 485                                   &gss_recv_token, &gss_w_token,
 486                                   0, GSS_C_QOP_DEFAULT);
 487
 488     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_unwrap")) {
 489       gss_release_buffer(&gss_status, &gss_recv_token);
 490       gss_release_buffer(&gss_status, &gss_w_token);
 491       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 492       failf(data, "Failed to unwrap GSSAPI encryption value into token.");
 493       return CURLE_COULDNT_CONNECT;
 494     }
 495     gss_release_buffer(&gss_status, &gss_recv_token);
 496
 497     if(gss_w_token.length != 1) {
 498       failf(data, "Invalid GSSAPI encryption response length (%d).",
 499             gss_w_token.length);
 500       gss_release_buffer(&gss_status, &gss_w_token);
 501       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 502       return CURLE_COULDNT_CONNECT;
 503     }
 504
 505     memcpy(socksreq,gss_w_token.value,gss_w_token.length);
 506     gss_release_buffer(&gss_status, &gss_w_token);
 507   }
 508   else {
 509     if(gss_recv_token.length != 1) {
 510       failf(data, "Invalid GSSAPI encryption response length (%d).",
 511             gss_recv_token.length);
 512       gss_release_buffer(&gss_status, &gss_recv_token);
 513       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 514       return CURLE_COULDNT_CONNECT;
 515     }
 516
 517     memcpy(socksreq,gss_recv_token.value,gss_recv_token.length);
 518     gss_release_buffer(&gss_status, &gss_recv_token);
 519   }
 520
 521   infof(data, "SOCKS5 access with%s protection granted.\n",
 522         (socksreq[0]==0)?"out gssapi data":
 523         ((socksreq[0]==1)?" gssapi integrity":" gssapi confidentiality"));
 524
 525   conn->socks5_gssapi_enctype = socksreq[0];
 526   if(socksreq[0] == 0)
 527     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 528
 529   return CURLE_OK;
 530 }
 531 #endif
 532
 533 #endif /* CURL_DISABLE_PROXY */