--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/socks_sspi.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,606 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2012 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 2009, 2011, 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 https://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.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#if defined(USE_WINDOWS_SSPI) && !defined(CURL_DISABLE_PROXY)
+
+#include "urldata.h"
+#include "sendf.h"
+#include "connect.h"
+#include "strerror.h"
+#include "timeval.h"
+#include "socks.h"
+#include "curl_sspi.h"
+#include "curl_multibyte.h"
+#include "warnless.h"
+#include "strdup.h"
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+/*
+ * Helper sspi error functions.
+ */
+static int check_sspi_err(struct connectdata *conn,
+                          SECURITY_STATUS status,
+                          const char *function)
+{
+  if(status != SEC_E_OK &&
+     status != SEC_I_COMPLETE_AND_CONTINUE &&
+     status != SEC_I_COMPLETE_NEEDED &&
+     status != SEC_I_CONTINUE_NEEDED) {
+    char buffer[STRERROR_LEN];
+    failf(conn->data, "SSPI error: %s failed: %s", function,
+          Curl_sspi_strerror(status, buffer, sizeof(buffer)));
+    return 1;
+  }
+  return 0;
+}
+
+/* This is the SSPI-using version of this function */
+CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
+                                      struct connectdata *conn)
+{
+  struct Curl_easy *data = conn->data;
+  curl_socket_t sock = conn->sock[sockindex];
+  CURLcode code;
+  ssize_t actualread;
+  ssize_t written;
+  int result;
+  /* Needs GSS-API authentication */
+  SECURITY_STATUS status;
+  unsigned long sspi_ret_flags = 0;
+  unsigned char gss_enc;
+  SecBuffer sspi_send_token, sspi_recv_token, sspi_w_token[3];
+  SecBufferDesc input_desc, output_desc, wrap_desc;
+  SecPkgContext_Sizes sspi_sizes;
+  CredHandle cred_handle;
+  CtxtHandle sspi_context;
+  PCtxtHandle context_handle = NULL;
+  SecPkgCredentials_Names names;
+  TimeStamp expiry;
+  char *service_name = NULL;
+  unsigned short us_length;
+  unsigned long qop;
+  unsigned char socksreq[4]; /* room for GSS-API exchange header only */
+  const char *service = data->set.str[STRING_PROXY_SERVICE_NAME] ?
+                        data->set.str[STRING_PROXY_SERVICE_NAME]  : "rcmd";
+  const size_t service_length = strlen(service);
+
+  /*   GSS-API request looks like
+   * +----+------+-----+----------------+
+   * |VER | MTYP | LEN |     TOKEN      |
+   * +----+------+----------------------+
+   * | 1  |  1   |  2  | up to 2^16 - 1 |
+   * +----+------+-----+----------------+
+   */
+
+  /* prepare service name */
+  if(strchr(service, '/')) {
+    service_name = strdup(service);
+    if(!service_name)
+      return CURLE_OUT_OF_MEMORY;
+  }
+  else {
+    service_name = malloc(service_length +
+                          strlen(conn->socks_proxy.host.name) + 2);
+    if(!service_name)
+      return CURLE_OUT_OF_MEMORY;
+    msnprintf(service_name, service_length +
+              strlen(conn->socks_proxy.host.name) + 2, "%s/%s",
+              service, conn->socks_proxy.host.name);
+  }
+
+  input_desc.cBuffers = 1;
+  input_desc.pBuffers = &sspi_recv_token;
+  input_desc.ulVersion = SECBUFFER_VERSION;
+
+  sspi_recv_token.BufferType = SECBUFFER_TOKEN;
+  sspi_recv_token.cbBuffer = 0;
+  sspi_recv_token.pvBuffer = NULL;
+
+  output_desc.cBuffers = 1;
+  output_desc.pBuffers = &sspi_send_token;
+  output_desc.ulVersion = SECBUFFER_VERSION;
+
+  sspi_send_token.BufferType = SECBUFFER_TOKEN;
+  sspi_send_token.cbBuffer = 0;
+  sspi_send_token.pvBuffer = NULL;
+
+  wrap_desc.cBuffers = 3;
+  wrap_desc.pBuffers = sspi_w_token;
+  wrap_desc.ulVersion = SECBUFFER_VERSION;
+
+  cred_handle.dwLower = 0;
+  cred_handle.dwUpper = 0;
+
+  status = s_pSecFn->AcquireCredentialsHandle(NULL,
+                                              (TCHAR *) TEXT("Kerberos"),
+                                              SECPKG_CRED_OUTBOUND,
+                                              NULL,
+                                              NULL,
+                                              NULL,
+                                              NULL,
+                                              &cred_handle,
+                                              &expiry);
+
+  if(check_sspi_err(conn, status, "AcquireCredentialsHandle")) {
+    failf(data, "Failed to acquire credentials.");
+    free(service_name);
+    s_pSecFn->FreeCredentialsHandle(&cred_handle);
+    return CURLE_COULDNT_CONNECT;
+  }
+
+  /* As long as we need to keep sending some context info, and there's no  */
+  /* errors, keep sending it...                                            */
+  for(;;) {
+    TCHAR *sname;
+
+    sname = Curl_convert_UTF8_to_tchar(service_name);
+    if(!sname)
+      return CURLE_OUT_OF_MEMORY;
+
+    status = s_pSecFn->InitializeSecurityContext(&cred_handle,
+                                                 context_handle,
+                                                 sname,
+                                                 ISC_REQ_MUTUAL_AUTH |
+                                                 ISC_REQ_ALLOCATE_MEMORY |
+                                                 ISC_REQ_CONFIDENTIALITY |
+                                                 ISC_REQ_REPLAY_DETECT,
+                                                 0,
+                                                 SECURITY_NATIVE_DREP,
+                                                 &input_desc,
+                                                 0,
+                                                 &sspi_context,
+                                                 &output_desc,
+                                                 &sspi_ret_flags,
+                                                 &expiry);
+
+    Curl_unicodefree(sname);
+
+    if(sspi_recv_token.pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+      sspi_recv_token.pvBuffer = NULL;
+      sspi_recv_token.cbBuffer = 0;
+    }
+
+    if(check_sspi_err(conn, status, "InitializeSecurityContext")) {
+      free(service_name);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      if(sspi_recv_token.pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+      failf(data, "Failed to initialise security context.");
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    if(sspi_send_token.cbBuffer != 0) {
+      socksreq[0] = 1;    /* GSS-API subnegotiation version */
+      socksreq[1] = 1;    /* authentication message type */
+      us_length = htons((short)sspi_send_token.cbBuffer);
+      memcpy(socksreq + 2, &us_length, sizeof(short));
+
+      code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
+      if(code || (4 != written)) {
+        failf(data, "Failed to send SSPI authentication request.");
+        free(service_name);
+        if(sspi_send_token.pvBuffer)
+          s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+        if(sspi_recv_token.pvBuffer)
+          s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+        s_pSecFn->FreeCredentialsHandle(&cred_handle);
+        s_pSecFn->DeleteSecurityContext(&sspi_context);
+        return CURLE_COULDNT_CONNECT;
+      }
+
+      code = Curl_write_plain(conn, sock, (char *)sspi_send_token.pvBuffer,
+                              sspi_send_token.cbBuffer, &written);
+      if(code || (sspi_send_token.cbBuffer != (size_t)written)) {
+        failf(data, "Failed to send SSPI authentication token.");
+        free(service_name);
+        if(sspi_send_token.pvBuffer)
+          s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+        if(sspi_recv_token.pvBuffer)
+          s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+        s_pSecFn->FreeCredentialsHandle(&cred_handle);
+        s_pSecFn->DeleteSecurityContext(&sspi_context);
+        return CURLE_COULDNT_CONNECT;
+      }
+
+    }
+
+    if(sspi_send_token.pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+      sspi_send_token.pvBuffer = NULL;
+    }
+    sspi_send_token.cbBuffer = 0;
+
+    if(sspi_recv_token.pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+      sspi_recv_token.pvBuffer = NULL;
+    }
+    sspi_recv_token.cbBuffer = 0;
+
+    if(status != SEC_I_CONTINUE_NEEDED)
+      break;
+
+    /* analyse response */
+
+    /*   GSS-API 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);
+    if(result || (actualread != 4)) {
+      failf(data, "Failed to receive SSPI authentication response.");
+      free(service_name);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      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 (%u %u).",
+            (unsigned int)socksreq[0], (unsigned int)socksreq[1]);
+      free(service_name);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    if(socksreq[1] != 1) { /* status / messgae type */
+      failf(data, "Invalid SSPI authentication response type (%u %u).",
+            (unsigned int)socksreq[0], (unsigned int)socksreq[1]);
+      free(service_name);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    memcpy(&us_length, socksreq + 2, sizeof(short));
+    us_length = ntohs(us_length);
+
+    sspi_recv_token.cbBuffer = us_length;
+    sspi_recv_token.pvBuffer = malloc(us_length);
+
+    if(!sspi_recv_token.pvBuffer) {
+      free(service_name);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_OUT_OF_MEMORY;
+    }
+    result = Curl_blockread_all(conn, sock, (char *)sspi_recv_token.pvBuffer,
+                                sspi_recv_token.cbBuffer, &actualread);
+
+    if(result || (actualread != us_length)) {
+      failf(data, "Failed to receive SSPI authentication token.");
+      free(service_name);
+      if(sspi_recv_token.pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_recv_token.pvBuffer);
+      s_pSecFn->FreeCredentialsHandle(&cred_handle);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    context_handle = &sspi_context;
+  }
+
+  free(service_name);
+
+  /* Everything is good so far, user was authenticated! */
+  status = s_pSecFn->QueryCredentialsAttributes(&cred_handle,
+                                                SECPKG_CRED_ATTR_NAMES,
+                                                &names);
+  s_pSecFn->FreeCredentialsHandle(&cred_handle);
+  if(check_sspi_err(conn, status, "QueryCredentialAttributes")) {
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    s_pSecFn->FreeContextBuffer(names.sUserName);
+    failf(data, "Failed to determine user name.");
+    return CURLE_COULDNT_CONNECT;
+  }
+  infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",
+        names.sUserName);
+  s_pSecFn->FreeContextBuffer(names.sUserName);
+
+  /* Do encryption */
+  socksreq[0] = 1;    /* GSS-API subnegotiation version */
+  socksreq[1] = 2;    /* encryption message type */
+
+  gss_enc = 0; /* no data protection */
+  /* do confidentiality protection if supported */
+  if(sspi_ret_flags & ISC_REQ_CONFIDENTIALITY)
+    gss_enc = 2;
+  /* else do integrity protection */
+  else if(sspi_ret_flags & ISC_REQ_INTEGRITY)
+    gss_enc = 1;
+
+  infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
+        (gss_enc == 0)?"no":((gss_enc == 1)?"integrity":"confidentiality") );
+  /* force to no data protection, avoid encryption/decryption for now */
+  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 {
+    status = s_pSecFn->QueryContextAttributes(&sspi_context,
+                                              SECPKG_ATTR_SIZES,
+                                              &sspi_sizes);
+    if(check_sspi_err(conn, status, "QueryContextAttributes")) {
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      failf(data, "Failed to query security context attributes.");
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    sspi_w_token[0].cbBuffer = sspi_sizes.cbSecurityTrailer;
+    sspi_w_token[0].BufferType = SECBUFFER_TOKEN;
+    sspi_w_token[0].pvBuffer = malloc(sspi_sizes.cbSecurityTrailer);
+
+    if(!sspi_w_token[0].pvBuffer) {
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_OUT_OF_MEMORY;
+    }
+
+    sspi_w_token[1].cbBuffer = 1;
+    sspi_w_token[1].pvBuffer = malloc(1);
+    if(!sspi_w_token[1].pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_OUT_OF_MEMORY;
+    }
+
+    memcpy(sspi_w_token[1].pvBuffer, &gss_enc, 1);
+    sspi_w_token[2].BufferType = SECBUFFER_PADDING;
+    sspi_w_token[2].cbBuffer = sspi_sizes.cbBlockSize;
+    sspi_w_token[2].pvBuffer = malloc(sspi_sizes.cbBlockSize);
+    if(!sspi_w_token[2].pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_OUT_OF_MEMORY;
+    }
+    status = s_pSecFn->EncryptMessage(&sspi_context,
+                                      KERB_WRAP_NO_ENCRYPT,
+                                      &wrap_desc,
+                                      0);
+    if(check_sspi_err(conn, status, "EncryptMessage")) {
+      s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[2].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      failf(data, "Failed to query security context attributes.");
+      return CURLE_COULDNT_CONNECT;
+    }
+    sspi_send_token.cbBuffer = sspi_w_token[0].cbBuffer
+      + sspi_w_token[1].cbBuffer
+      + sspi_w_token[2].cbBuffer;
+    sspi_send_token.pvBuffer = malloc(sspi_send_token.cbBuffer);
+    if(!sspi_send_token.pvBuffer) {
+      s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[2].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_OUT_OF_MEMORY;
+    }
+
+    memcpy(sspi_send_token.pvBuffer, sspi_w_token[0].pvBuffer,
+           sspi_w_token[0].cbBuffer);
+    memcpy((PUCHAR) sspi_send_token.pvBuffer +(int)sspi_w_token[0].cbBuffer,
+           sspi_w_token[1].pvBuffer, sspi_w_token[1].cbBuffer);
+    memcpy((PUCHAR) sspi_send_token.pvBuffer
+           + sspi_w_token[0].cbBuffer
+           + sspi_w_token[1].cbBuffer,
+           sspi_w_token[2].pvBuffer, sspi_w_token[2].cbBuffer);
+
+    s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+    sspi_w_token[0].pvBuffer = NULL;
+    sspi_w_token[0].cbBuffer = 0;
+    s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+    sspi_w_token[1].pvBuffer = NULL;
+    sspi_w_token[1].cbBuffer = 0;
+    s_pSecFn->FreeContextBuffer(sspi_w_token[2].pvBuffer);
+    sspi_w_token[2].pvBuffer = NULL;
+    sspi_w_token[2].cbBuffer = 0;
+
+    us_length = htons((short)sspi_send_token.cbBuffer);
+    memcpy(socksreq + 2, &us_length, sizeof(short));
+  }
+
+  code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
+  if(code || (4 != written)) {
+    failf(data, "Failed to send SSPI encryption request.");
+    if(sspi_send_token.pvBuffer)
+      s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    return CURLE_COULDNT_CONNECT;
+  }
+
+  if(data->set.socks5_gssapi_nec) {
+    memcpy(socksreq, &gss_enc, 1);
+    code = Curl_write_plain(conn, sock, (char *)socksreq, 1, &written);
+    if(code || (1 != written)) {
+      failf(data, "Failed to send SSPI encryption type.");
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+  }
+  else {
+    code = Curl_write_plain(conn, sock, (char *)sspi_send_token.pvBuffer,
+                            sspi_send_token.cbBuffer, &written);
+    if(code || (sspi_send_token.cbBuffer != (size_t)written)) {
+      failf(data, "Failed to send SSPI encryption type.");
+      if(sspi_send_token.pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+    if(sspi_send_token.pvBuffer)
+      s_pSecFn->FreeContextBuffer(sspi_send_token.pvBuffer);
+  }
+
+  result = Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
+  if(result || (actualread != 4)) {
+    failf(data, "Failed to receive SSPI encryption response.");
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    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 (%u %u).",
+          (unsigned int)socksreq[0], (unsigned int)socksreq[1]);
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    return CURLE_COULDNT_CONNECT;
+  }
+
+  if(socksreq[1] != 2) { /* status / message type */
+    failf(data, "Invalid SSPI encryption response type (%u %u).",
+          (unsigned int)socksreq[0], (unsigned int)socksreq[1]);
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    return CURLE_COULDNT_CONNECT;
+  }
+
+  memcpy(&us_length, socksreq + 2, sizeof(short));
+  us_length = ntohs(us_length);
+
+  sspi_w_token[0].cbBuffer = us_length;
+  sspi_w_token[0].pvBuffer = malloc(us_length);
+  if(!sspi_w_token[0].pvBuffer) {
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    return CURLE_OUT_OF_MEMORY;
+  }
+
+  result = Curl_blockread_all(conn, sock, (char *)sspi_w_token[0].pvBuffer,
+                              sspi_w_token[0].cbBuffer, &actualread);
+
+  if(result || (actualread != us_length)) {
+    failf(data, "Failed to receive SSPI encryption type.");
+    s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+    s_pSecFn->DeleteSecurityContext(&sspi_context);
+    return CURLE_COULDNT_CONNECT;
+  }
+
+
+  if(!data->set.socks5_gssapi_nec) {
+    wrap_desc.cBuffers = 2;
+    sspi_w_token[0].BufferType = SECBUFFER_STREAM;
+    sspi_w_token[1].BufferType = SECBUFFER_DATA;
+    sspi_w_token[1].cbBuffer = 0;
+    sspi_w_token[1].pvBuffer = NULL;
+
+    status = s_pSecFn->DecryptMessage(&sspi_context,
+                                      &wrap_desc,
+                                      0,
+                                      &qop);
+
+    if(check_sspi_err(conn, status, "DecryptMessage")) {
+      if(sspi_w_token[0].pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      if(sspi_w_token[1].pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      failf(data, "Failed to query security context attributes.");
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    if(sspi_w_token[1].cbBuffer != 1) {
+      failf(data, "Invalid SSPI encryption response length (%lu).",
+            (unsigned long)sspi_w_token[1].cbBuffer);
+      if(sspi_w_token[0].pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      if(sspi_w_token[1].pvBuffer)
+        s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+
+    memcpy(socksreq, sspi_w_token[1].pvBuffer, sspi_w_token[1].cbBuffer);
+    s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+    s_pSecFn->FreeContextBuffer(sspi_w_token[1].pvBuffer);
+  }
+  else {
+    if(sspi_w_token[0].cbBuffer != 1) {
+      failf(data, "Invalid SSPI encryption response length (%lu).",
+            (unsigned long)sspi_w_token[0].cbBuffer);
+      s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+      s_pSecFn->DeleteSecurityContext(&sspi_context);
+      return CURLE_COULDNT_CONNECT;
+    }
+    memcpy(socksreq, sspi_w_token[0].pvBuffer, sspi_w_token[0].cbBuffer);
+    s_pSecFn->FreeContextBuffer(sspi_w_token[0].pvBuffer);
+  }
+
+  infof(data, "SOCKS5 access with%s protection granted.\n",
+        (socksreq[0] == 0)?"out GSS-API data":
+        ((socksreq[0] == 1)?" GSS-API integrity":" GSS-API confidentiality"));
+
+  /* For later use if encryption is required
+     conn->socks5_gssapi_enctype = socksreq[0];
+     if(socksreq[0] != 0)
+       conn->socks5_sspi_context = sspi_context;
+     else {
+       s_pSecFn->DeleteSecurityContext(&sspi_context);
+       conn->socks5_sspi_context = sspi_context;
+     }
+  */
+  return CURLE_OK;
+}
+#endif