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 - 2014, 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 GSS-API 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, "GSS-API 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 GSS-API exchange header only */
 135   char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
 136
 137   /*   GSS-API 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                                                  &Curl_krb5_mech_oid,
 185                                                  NULL,
 186                                                  gss_token,
 187                                                  &gss_send_token,
 188                                                  TRUE,
 189                                                  &gss_ret_flags);
 190
 191     if(gss_token != GSS_C_NO_BUFFER)
 192       gss_release_buffer(&gss_status, &gss_recv_token);
 193     if(check_gss_err(data,gss_major_status,
 194                      gss_minor_status,"gss_init_sec_context")) {
 195       gss_release_name(&gss_status, &server);
 196       gss_release_buffer(&gss_status, &gss_recv_token);
 197       gss_release_buffer(&gss_status, &gss_send_token);
 198       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 199       failf(data, "Failed to initial GSS-API token.");
 200       return CURLE_COULDNT_CONNECT;
 201     }
 202
 203     if(gss_send_token.length != 0) {
 204       socksreq[0] = 1;    /* GSS-API subnegotiation version */
 205       socksreq[1] = 1;    /* authentication message type */
 206       us_length = htons((short)gss_send_token.length);
 207       memcpy(socksreq+2,&us_length,sizeof(short));
 208
 209       code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 210       if(code || (4 != written)) {
 211         failf(data, "Failed to send GSS-API authentication request.");
 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       code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
 220                               gss_send_token.length, &written);
 221
 222       if(code || ((ssize_t)gss_send_token.length != written)) {
 223         failf(data, "Failed to send GSS-API authentication token.");
 224         gss_release_name(&gss_status, &server);
 225         gss_release_buffer(&gss_status, &gss_recv_token);
 226         gss_release_buffer(&gss_status, &gss_send_token);
 227         gss_delete_sec_context(&gss_status, &gss_context, NULL);
 228         return CURLE_COULDNT_CONNECT;
 229       }
 230
 231     }
 232
 233     gss_release_buffer(&gss_status, &gss_send_token);
 234     gss_release_buffer(&gss_status, &gss_recv_token);
 235     if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
 236
 237     /* analyse response */
 238
 239     /*   GSS-API response looks like
 240      * +----+------+-----+----------------+
 241      * |VER | MTYP | LEN |     TOKEN      |
 242      * +----+------+----------------------+
 243      * | 1  |  1   |  2  | up to 2^16 - 1 |
 244      * +----+------+-----+----------------+
 245      */
 246
 247     result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 248     if(result || (actualread != 4)) {
 249       failf(data, "Failed to receive GSS-API authentication response.");
 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     /* ignore the first (VER) byte */
 256     if(socksreq[1] == 255) { /* status / message type */
 257       failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 258             socksreq[0], socksreq[1]);
 259       gss_release_name(&gss_status, &server);
 260       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 261       return CURLE_COULDNT_CONNECT;
 262     }
 263
 264     if(socksreq[1] != 1) { /* status / messgae type */
 265       failf(data, "Invalid GSS-API authentication response type (%d %d).",
 266             socksreq[0], socksreq[1]);
 267       gss_release_name(&gss_status, &server);
 268       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 269       return CURLE_COULDNT_CONNECT;
 270     }
 271
 272     memcpy(&us_length, socksreq+2, sizeof(short));
 273     us_length = ntohs(us_length);
 274
 275     gss_recv_token.length=us_length;
 276     gss_recv_token.value=malloc(us_length);
 277     if(!gss_recv_token.value) {
 278       failf(data,
 279             "Could not allocate memory for GSS-API authentication "
 280             "response token.");
 281       gss_release_name(&gss_status, &server);
 282       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 283       return CURLE_OUT_OF_MEMORY;
 284     }
 285
 286     result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 287                               gss_recv_token.length, &actualread);
 288
 289     if(result || (actualread != us_length)) {
 290       failf(data, "Failed to receive GSS-API authentication token.");
 291       gss_release_name(&gss_status, &server);
 292       gss_release_buffer(&gss_status, &gss_recv_token);
 293       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 294       return CURLE_COULDNT_CONNECT;
 295     }
 296
 297     gss_token = &gss_recv_token;
 298   }
 299
 300   gss_release_name(&gss_status, &server);
 301
 302   /* Everything is good so far, user was authenticated! */
 303   gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
 304                                           &gss_client_name, NULL, NULL, NULL,
 305                                           NULL, NULL, NULL);
 306   if(check_gss_err(data,gss_major_status,
 307                    gss_minor_status,"gss_inquire_context")) {
 308     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 309     gss_release_name(&gss_status, &gss_client_name);
 310     failf(data, "Failed to determine user name.");
 311     return CURLE_COULDNT_CONNECT;
 312   }
 313   gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
 314                                       &gss_send_token, NULL);
 315   if(check_gss_err(data,gss_major_status,
 316                    gss_minor_status,"gss_display_name")) {
 317     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 318     gss_release_name(&gss_status, &gss_client_name);
 319     gss_release_buffer(&gss_status, &gss_send_token);
 320     failf(data, "Failed to determine user name.");
 321     return CURLE_COULDNT_CONNECT;
 322   }
 323   user=malloc(gss_send_token.length+1);
 324   if(!user) {
 325     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 326     gss_release_name(&gss_status, &gss_client_name);
 327     gss_release_buffer(&gss_status, &gss_send_token);
 328     return CURLE_OUT_OF_MEMORY;
 329   }
 330
 331   memcpy(user, gss_send_token.value, gss_send_token.length);
 332   user[gss_send_token.length] = '\0';
 333   gss_release_name(&gss_status, &gss_client_name);
 334   gss_release_buffer(&gss_status, &gss_send_token);
 335   infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
 336   free(user);
 337   user=NULL;
 338
 339   /* Do encryption */
 340   socksreq[0] = 1;    /* GSS-API subnegotiation version */
 341   socksreq[1] = 2;    /* encryption message type */
 342
 343   gss_enc = 0; /* no data protection */
 344   /* do confidentiality protection if supported */
 345   if(gss_ret_flags & GSS_C_CONF_FLAG)
 346     gss_enc = 2;
 347   /* else do integrity protection */
 348   else if(gss_ret_flags & GSS_C_INTEG_FLAG)
 349     gss_enc = 1;
 350
 351   infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
 352         (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
 353   /* force for the moment to no data protection */
 354   gss_enc = 0;
 355   /*
 356    * Sending the encryption type in clear seems wrong. It should be
 357    * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
 358    * The NEC reference implementations on which this is based is
 359    * therefore at fault
 360    *
 361    *  +------+------+------+.......................+
 362    *  + ver  | mtyp | len  |   token               |
 363    *  +------+------+------+.......................+
 364    *  + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
 365    *  +------+------+------+.......................+
 366    *
 367    *   Where:
 368    *
 369    *  - "ver" is the protocol version number, here 1 to represent the
 370    *    first version of the SOCKS/GSS-API protocol
 371    *
 372    *  - "mtyp" is the message type, here 2 to represent a protection
 373    *    -level negotiation message
 374    *
 375    *  - "len" is the length of the "token" field in octets
 376    *
 377    *  - "token" is the GSS-API encapsulated protection level
 378    *
 379    * The token is produced by encapsulating an octet containing the
 380    * required protection level using gss_seal()/gss_wrap() with conf_req
 381    * set to FALSE.  The token is verified using gss_unseal()/
 382    * gss_unwrap().
 383    *
 384    */
 385   if(data->set.socks5_gssapi_nec) {
 386     us_length = htons((short)1);
 387     memcpy(socksreq+2,&us_length,sizeof(short));
 388   }
 389   else {
 390     gss_send_token.length = 1;
 391     gss_send_token.value = malloc(1);
 392     if(!gss_send_token.value) {
 393       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 394       return CURLE_OUT_OF_MEMORY;
 395     }
 396     memcpy(gss_send_token.value, &gss_enc, 1);
 397
 398     gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
 399                                 GSS_C_QOP_DEFAULT, &gss_send_token,
 400                                 &gss_conf_state, &gss_w_token);
 401
 402     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_wrap")) {
 403       gss_release_buffer(&gss_status, &gss_send_token);
 404       gss_release_buffer(&gss_status, &gss_w_token);
 405       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 406       failf(data, "Failed to wrap GSS-API encryption value into token.");
 407       return CURLE_COULDNT_CONNECT;
 408     }
 409     gss_release_buffer(&gss_status, &gss_send_token);
 410
 411     us_length = htons((short)gss_w_token.length);
 412     memcpy(socksreq+2,&us_length,sizeof(short));
 413   }
 414
 415   code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
 416   if(code  || (4 != written)) {
 417     failf(data, "Failed to send GSS-API encryption request.");
 418     gss_release_buffer(&gss_status, &gss_w_token);
 419     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 420     return CURLE_COULDNT_CONNECT;
 421   }
 422
 423   if(data->set.socks5_gssapi_nec) {
 424     memcpy(socksreq, &gss_enc, 1);
 425     code = Curl_write_plain(conn, sock, socksreq, 1, &written);
 426     if(code || ( 1 != written)) {
 427       failf(data, "Failed to send GSS-API encryption type.");
 428       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 429       return CURLE_COULDNT_CONNECT;
 430     }
 431   }
 432   else {
 433     code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
 434                             gss_w_token.length, &written);
 435     if(code || ((ssize_t)gss_w_token.length != written)) {
 436       failf(data, "Failed to send GSS-API encryption type.");
 437       gss_release_buffer(&gss_status, &gss_w_token);
 438       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 439       return CURLE_COULDNT_CONNECT;
 440     }
 441     gss_release_buffer(&gss_status, &gss_w_token);
 442   }
 443
 444   result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
 445   if(result || (actualread != 4)) {
 446     failf(data, "Failed to receive GSS-API encryption response.");
 447     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 448     return CURLE_COULDNT_CONNECT;
 449   }
 450
 451   /* ignore the first (VER) byte */
 452   if(socksreq[1] == 255) { /* status / message type */
 453     failf(data, "User was rejected by the SOCKS5 server (%d %d).",
 454           socksreq[0], socksreq[1]);
 455     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 456     return CURLE_COULDNT_CONNECT;
 457   }
 458
 459   if(socksreq[1] != 2) { /* status / messgae type */
 460     failf(data, "Invalid GSS-API encryption response type (%d %d).",
 461           socksreq[0], socksreq[1]);
 462     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 463     return CURLE_COULDNT_CONNECT;
 464   }
 465
 466   memcpy(&us_length, socksreq+2, sizeof(short));
 467   us_length = ntohs(us_length);
 468
 469   gss_recv_token.length= us_length;
 470   gss_recv_token.value=malloc(gss_recv_token.length);
 471   if(!gss_recv_token.value) {
 472     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 473     return CURLE_OUT_OF_MEMORY;
 474   }
 475   result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
 476                             gss_recv_token.length, &actualread);
 477
 478   if(result || (actualread != us_length)) {
 479     failf(data, "Failed to receive GSS-API encryptrion type.");
 480     gss_release_buffer(&gss_status, &gss_recv_token);
 481     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 482     return CURLE_COULDNT_CONNECT;
 483   }
 484
 485   if(!data->set.socks5_gssapi_nec) {
 486     gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
 487                                   &gss_recv_token, &gss_w_token,
 488                                   0, GSS_C_QOP_DEFAULT);
 489
 490     if(check_gss_err(data,gss_major_status,gss_minor_status,"gss_unwrap")) {
 491       gss_release_buffer(&gss_status, &gss_recv_token);
 492       gss_release_buffer(&gss_status, &gss_w_token);
 493       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 494       failf(data, "Failed to unwrap GSS-API encryption value into token.");
 495       return CURLE_COULDNT_CONNECT;
 496     }
 497     gss_release_buffer(&gss_status, &gss_recv_token);
 498
 499     if(gss_w_token.length != 1) {
 500       failf(data, "Invalid GSS-API encryption response length (%d).",
 501             gss_w_token.length);
 502       gss_release_buffer(&gss_status, &gss_w_token);
 503       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 504       return CURLE_COULDNT_CONNECT;
 505     }
 506
 507     memcpy(socksreq,gss_w_token.value,gss_w_token.length);
 508     gss_release_buffer(&gss_status, &gss_w_token);
 509   }
 510   else {
 511     if(gss_recv_token.length != 1) {
 512       failf(data, "Invalid GSS-API encryption response length (%d).",
 513             gss_recv_token.length);
 514       gss_release_buffer(&gss_status, &gss_recv_token);
 515       gss_delete_sec_context(&gss_status, &gss_context, NULL);
 516       return CURLE_COULDNT_CONNECT;
 517     }
 518
 519     memcpy(socksreq,gss_recv_token.value,gss_recv_token.length);
 520     gss_release_buffer(&gss_status, &gss_recv_token);
 521   }
 522
 523   infof(data, "SOCKS5 access with%s protection granted.\n",
 524         (socksreq[0]==0)?"out GSS-API data":
 525         ((socksreq[0]==1)?" GSS-API integrity":" GSS-API confidentiality"));
 526
 527   conn->socks5_gssapi_enctype = socksreq[0];
 528   if(socksreq[0] == 0)
 529     gss_delete_sec_context(&gss_status, &gss_context, NULL);
 530
 531   return CURLE_OK;
 532 }
 533 #endif
 534
 535 #endif /* CURL_DISABLE_PROXY */