- Markus Moeller introduced two new options to libcurl:

  CURLOPT_SOCKS5_GSSAPI_SERVICE and CURLOPT_SOCKS5_GSSAPI_NEC to allow libcurl
  to do GSS-style authentication with SOCKS5 proxies. The curl tool got the
  options called --socks5-gssapi-service and --socks5-gssapi-nec to enable
  these.

1 files changed, 547 insertions, 0 deletions

diff --git a/lib/socks_gssapi.c b/lib/socks_gssapi.c
new file mode 100644
index 000000000..cd9e1a4d3
--- /dev/null
+++ b/lib/socks_gssapi.c
@@ -0,0 +1,547 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2009, Markus Moeller, <markus_moeller@compuserve.com>
+ *
+ * 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.
+ *
+ * $Id$
+ ***************************************************************************/
+
+#include "setup.h"
+
+#ifdef HAVE_GSSAPI
+#ifdef HAVE_OLD_GSSMIT
+#define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
+#endif
+#ifndef gss_nt_service_name
+#define gss_nt_service_name GSS_C_NT_HOSTBASED_SERVICE
+#endif
+#include <string.h>
+
+#ifdef NEED_MALLOC_H
+#include <malloc.h>
+#endif
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#include "urldata.h"
+#include "sendf.h"
+#include "connect.h"
+#include "timeval.h"
+#include "socks.h"
+
+static gss_ctx_id_t     gss_context = GSS_C_NO_CONTEXT;
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+/* The last #include file should be: */
+#include "memdebug.h"
+
+/*
+ * Helper gssapi 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);
+          len += status_string.length;
+        }
+        gss_release_buffer(&min_stat, &status_string);
+        break;
+      }
+      gss_release_buffer(&min_stat, &status_string);
+    }
+    failf(data, "GSSAPI error: %s failed:\n%s\n", 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;
+  long timeout;
+  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;
+  u_short          us_length;
+  char             *user=NULL;
+  unsigned char socksreq[4]; /* room for gssapi exchange header only */
+  char *serviceptr = data->set.str[STRING_SOCKS5_GSSAPI_SERVICE];
+
+  /* get timeout */
+  timeout = Curl_timeleft(conn, NULL, TRUE);
+
+  /*   GSSAPI 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 = gss_init_sec_context(&gss_minor_status,
+                                            GSS_C_NO_CREDENTIAL,
+                                            &gss_context, server,
+                                            GSS_C_NULL_OID,
+                                            GSS_C_MUTUAL_FLAG |
+                                            GSS_C_REPLAY_FLAG,
+                                            0,
+                                            NULL,
+                                            gss_token,
+                                            NULL,
+                                            &gss_send_token,
+                                            &gss_ret_flags,
+                                            NULL);
+
+    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 GSSAPI token.");
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    if(gss_send_token.length != 0) {
+      socksreq[0] = 1;    /* gssapi 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 != CURLE_OK) || (4 != written)) {
+        failf(data, "Failed to send GSSAPI 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 != CURLE_OK) || ((ssize_t)gss_send_token.length != written)) {
+        failf(data, "Failed to send GSSAPI 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 */
+
+    /*   GSSAPI 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, timeout);
+    if(result != CURLE_OK || actualread != 4) {
+      failf(data, "Failed to receive GSSAPI 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 GSSAPI 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 GSSAPI 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, timeout);
+
+    if(result != CURLE_OK || actualread != us_length) {
+      failf(data, "Failed to receive GSSAPI 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 gssapi.\n",user);
+  free(user);
+  user=NULL;
+
+  /* Do encryption */
+  socksreq[0] = 1;    /* gssapi 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 gssapi %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 GSSAPI 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 != CURLE_OK) || (4 != written)) {
+    failf(data, "Failed to send GSSAPI 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 != CURLE_OK) || ( 1 != written)) {
+      failf(data, "Failed to send GSSAPI 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 != CURLE_OK) || ((ssize_t)gss_w_token.length != written)) {
+      failf(data, "Failed to send GSSAPI 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, timeout);
+  if(result != CURLE_OK || actualread != 4) {
+    failf(data, "Failed to receive GSSAPI 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 GSSAPI 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, timeout);
+
+  if(result != CURLE_OK || actualread != us_length) {
+    failf(data, "Failed to receive GSSAPI 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 GSSAPI 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 GSSAPI 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 GSSAPI 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 gssapi data":
+        ((socksreq[0]==1)?" gssapi integrity":" gssapi confidentiality"));
+
+  conn->socks5_gssapi_enctype = socksreq[0];
+  if(socksreq[0] == 0)
+    gss_delete_sec_context(&gss_status, &gss_context, NULL);
+
+  return CURLE_OK;
+}
+#endif