libcurl extracted to the separate lib

git-svn-id: http://svn.miranda-ng.org/main/trunk@14683 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 1308 insertions, 0 deletions

diff --git a/libs/libcurl/src/curl_schannel.c b/libs/libcurl/src/curl_schannel.c
new file mode 100644
index 0000000000..68139db586
--- /dev/null
+++ b/libs/libcurl/src/curl_schannel.c
@@ -0,0 +1,1308 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2012 - 2013, Marc Hoersken, <info@marc-hoersken.de>
+ * Copyright (C) 2012, Mark Salisbury, <mark.salisbury@hp.com>
+ * Copyright (C) 2012 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * 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.
+ *
+ ***************************************************************************/
+
+/*
+ * Source file for all SChannel-specific code for the TLS/SSL layer. No code
+ * but sslgen.c should ever call or use these functions.
+ *
+ */
+
+/*
+ * Based upon the PolarSSL implementation in polarssl.c and polarssl.h:
+ *   Copyright (C) 2010, 2011, Hoi-Ho Chan, <hoiho.chan@gmail.com>
+ *
+ * Based upon the CyaSSL implementation in cyassl.c and cyassl.h:
+ *   Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * Thanks for code and inspiration!
+ */
+
+/*
+ * TODO list for TLS/SSL implementation:
+ * - implement client certificate authentication
+ * - implement custom server certificate validation
+ * - implement cipher/algorithm option
+ *
+ * Related articles on MSDN:
+ * - Getting a Certificate for Schannel
+ *   http://msdn.microsoft.com/en-us/library/windows/desktop/aa375447.aspx
+ * - Specifying Schannel Ciphers and Cipher Strengths
+ *   http://msdn.microsoft.com/en-us/library/windows/desktop/aa380161.aspx
+ */
+
+#include "curl_setup.h"
+
+#ifdef USE_SCHANNEL
+
+#ifndef USE_WINDOWS_SSPI
+#  error "Can't compile SCHANNEL support without SSPI."
+#endif
+
+#include "curl_sspi.h"
+#include "curl_schannel.h"
+#include "sslgen.h"
+#include "sendf.h"
+#include "connect.h" /* for the connect timeout */
+#include "strerror.h"
+#include "select.h" /* for the socket readyness */
+#include "inet_pton.h" /* for IP addr SNI check */
+#include "curl_multibyte.h"
+#include "warnless.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+#include "curl_memory.h"
+/* The last #include file should be: */
+#include "memdebug.h"
+
+/* Uncomment to force verbose output
+ * #define infof(x, y, ...) printf(y, __VA_ARGS__)
+ * #define failf(x, y, ...) printf(y, __VA_ARGS__)
+ */
+
+static Curl_recv schannel_recv;
+static Curl_send schannel_send;
+
+#ifdef _WIN32_WCE
+static CURLcode verify_certificate(struct connectdata *conn, int sockindex);
+#endif
+
+static void InitSecBuffer(SecBuffer *buffer, unsigned long BufType,
+                          void *BufDataPtr, unsigned long BufByteSize)
+{
+  buffer->cbBuffer = BufByteSize;
+  buffer->BufferType = BufType;
+  buffer->pvBuffer = BufDataPtr;
+}
+
+static void InitSecBufferDesc(SecBufferDesc *desc, SecBuffer *BufArr,
+                              unsigned long NumArrElem)
+{
+  desc->ulVersion = SECBUFFER_VERSION;
+  desc->pBuffers = BufArr;
+  desc->cBuffers = NumArrElem;
+}
+
+static CURLcode
+schannel_connect_step1(struct connectdata *conn, int sockindex)
+{
+  ssize_t written = -1;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  SecBuffer outbuf;
+  SecBufferDesc outbuf_desc;
+  SCHANNEL_CRED schannel_cred;
+  SECURITY_STATUS sspi_status = SEC_E_OK;
+  struct curl_schannel_cred *old_cred = NULL;
+  struct in_addr addr;
+#ifdef ENABLE_IPV6
+  struct in6_addr addr6;
+#endif
+  TCHAR *host_name;
+  CURLcode code;
+
+  infof(data, "schannel: SSL/TLS connection with %s port %hu (step 1/3)\n",
+        conn->host.name, conn->remote_port);
+
+  /* check for an existing re-usable credential handle */
+  if(!Curl_ssl_getsessionid(conn, (void**)&old_cred, NULL)) {
+    connssl->cred = old_cred;
+    infof(data, "schannel: re-using existing credential handle\n");
+  }
+  else {
+    /* setup Schannel API options */
+    memset(&schannel_cred, 0, sizeof(schannel_cred));
+    schannel_cred.dwVersion = SCHANNEL_CRED_VERSION;
+
+    if(data->set.ssl.verifypeer) {
+#ifdef _WIN32_WCE
+      /* certificate validation on CE doesn't seem to work right; we'll
+         do it following a more manual process. */
+      schannel_cred.dwFlags = SCH_CRED_MANUAL_CRED_VALIDATION |
+                              SCH_CRED_IGNORE_NO_REVOCATION_CHECK |
+                              SCH_CRED_IGNORE_REVOCATION_OFFLINE;
+#else
+      schannel_cred.dwFlags = SCH_CRED_AUTO_CRED_VALIDATION |
+                              SCH_CRED_REVOCATION_CHECK_CHAIN;
+#endif
+      infof(data, "schannel: checking server certificate revocation\n");
+    }
+    else {
+      schannel_cred.dwFlags = SCH_CRED_MANUAL_CRED_VALIDATION |
+                              SCH_CRED_IGNORE_NO_REVOCATION_CHECK |
+                              SCH_CRED_IGNORE_REVOCATION_OFFLINE;
+      infof(data, "schannel: disable server certificate revocation checks\n");
+    }
+
+    if(Curl_inet_pton(AF_INET, conn->host.name, &addr)
+#ifdef ENABLE_IPV6
+       || Curl_inet_pton(AF_INET6, conn->host.name, &addr6)
+#endif
+      ) {
+      schannel_cred.dwFlags |= SCH_CRED_NO_SERVERNAME_CHECK;
+      infof(data, "schannel: using IP address, SNI is being disabled by "
+                  "disabling the servername check against the "
+                  "subject names in server certificates.\n");
+    }
+
+    if(!data->set.ssl.verifyhost) {
+      schannel_cred.dwFlags |= SCH_CRED_NO_SERVERNAME_CHECK;
+      infof(data, "schannel: verifyhost setting prevents Schannel from "
+                  "comparing the supplied target name with the subject "
+                  "names in server certificates. Also disables SNI.\n");
+    }
+
+    switch(data->set.ssl.version) {
+      case CURL_SSLVERSION_TLSv1:
+        schannel_cred.grbitEnabledProtocols = SP_PROT_TLS1_0_CLIENT |
+                                              SP_PROT_TLS1_1_CLIENT |
+                                              SP_PROT_TLS1_2_CLIENT;
+        break;
+      case CURL_SSLVERSION_SSLv3:
+        schannel_cred.grbitEnabledProtocols = SP_PROT_SSL3_CLIENT;
+        break;
+      case CURL_SSLVERSION_SSLv2:
+        schannel_cred.grbitEnabledProtocols = SP_PROT_SSL2_CLIENT;
+        break;
+    }
+
+    /* allocate memory for the re-usable credential handle */
+    connssl->cred = malloc(sizeof(struct curl_schannel_cred));
+    if(!connssl->cred) {
+      failf(data, "schannel: unable to allocate memory");
+      return CURLE_OUT_OF_MEMORY;
+    }
+    memset(connssl->cred, 0, sizeof(struct curl_schannel_cred));
+
+    /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa374716.aspx */
+    sspi_status = s_pSecFn->AcquireCredentialsHandle(NULL, (TCHAR *)UNISP_NAME,
+      SECPKG_CRED_OUTBOUND, NULL, &schannel_cred, NULL, NULL,
+      &connssl->cred->cred_handle, &connssl->cred->time_stamp);
+
+    if(sspi_status != SEC_E_OK) {
+      if(sspi_status == SEC_E_WRONG_PRINCIPAL)
+        failf(data, "schannel: SNI or certificate check failed: %s",
+              Curl_sspi_strerror(conn, sspi_status));
+      else
+        failf(data, "schannel: AcquireCredentialsHandle failed: %s",
+              Curl_sspi_strerror(conn, sspi_status));
+      Curl_safefree(connssl->cred);
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+  }
+
+  /* setup output buffer */
+  InitSecBuffer(&outbuf, SECBUFFER_EMPTY, NULL, 0);
+  InitSecBufferDesc(&outbuf_desc, &outbuf, 1);
+
+  /* setup request flags */
+  connssl->req_flags = ISC_REQ_SEQUENCE_DETECT | ISC_REQ_REPLAY_DETECT |
+                       ISC_REQ_CONFIDENTIALITY | ISC_REQ_ALLOCATE_MEMORY |
+                       ISC_REQ_STREAM;
+
+  /* allocate memory for the security context handle */
+  connssl->ctxt = malloc(sizeof(struct curl_schannel_ctxt));
+  if(!connssl->ctxt) {
+    failf(data, "schannel: unable to allocate memory");
+    return CURLE_OUT_OF_MEMORY;
+  }
+  memset(connssl->ctxt, 0, sizeof(struct curl_schannel_ctxt));
+
+  host_name = Curl_convert_UTF8_to_tchar(conn->host.name);
+  if(!host_name)
+    return CURLE_OUT_OF_MEMORY;
+
+  /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa375924.aspx */
+
+  sspi_status = s_pSecFn->InitializeSecurityContext(
+    &connssl->cred->cred_handle, NULL, host_name,
+    connssl->req_flags, 0, 0, NULL, 0, &connssl->ctxt->ctxt_handle,
+    &outbuf_desc, &connssl->ret_flags, &connssl->ctxt->time_stamp);
+
+  Curl_unicodefree(host_name);
+
+  if(sspi_status != SEC_I_CONTINUE_NEEDED) {
+    if(sspi_status == SEC_E_WRONG_PRINCIPAL)
+      failf(data, "schannel: SNI or certificate check failed: %s",
+            Curl_sspi_strerror(conn, sspi_status));
+    else
+      failf(data, "schannel: initial InitializeSecurityContext failed: %s",
+            Curl_sspi_strerror(conn, sspi_status));
+    Curl_safefree(connssl->ctxt);
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+
+  infof(data, "schannel: sending initial handshake data: "
+        "sending %lu bytes...\n", outbuf.cbBuffer);
+
+  /* send initial handshake data which is now stored in output buffer */
+  code = Curl_write_plain(conn, conn->sock[sockindex], outbuf.pvBuffer,
+                          outbuf.cbBuffer, &written);
+  s_pSecFn->FreeContextBuffer(outbuf.pvBuffer);
+  if((code != CURLE_OK) || (outbuf.cbBuffer != (size_t)written)) {
+    failf(data, "schannel: failed to send initial handshake data: "
+          "sent %zd of %lu bytes", written, outbuf.cbBuffer);
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+
+  infof(data, "schannel: sent initial handshake data: "
+        "sent %zd bytes\n", written);
+
+  /* continue to second handshake step */
+  connssl->connecting_state = ssl_connect_2;
+
+  return CURLE_OK;
+}
+
+static CURLcode
+schannel_connect_step2(struct connectdata *conn, int sockindex)
+{
+  int i;
+  ssize_t nread = -1, written = -1;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  SecBuffer outbuf[2];
+  SecBufferDesc outbuf_desc;
+  SecBuffer inbuf[2];
+  SecBufferDesc inbuf_desc;
+  SECURITY_STATUS sspi_status = SEC_E_OK;
+  TCHAR *host_name;
+  CURLcode code;
+  bool doread;
+
+  doread = (connssl->connecting_state != ssl_connect_2_writing) ? TRUE : FALSE;
+
+  infof(data, "schannel: SSL/TLS connection with %s port %hu (step 2/3)\n",
+        conn->host.name, conn->remote_port);
+
+  /* buffer to store previously received and encrypted data */
+  if(connssl->encdata_buffer == NULL) {
+    connssl->encdata_offset = 0;
+    connssl->encdata_length = CURL_SCHANNEL_BUFFER_INIT_SIZE;
+    connssl->encdata_buffer = malloc(connssl->encdata_length);
+    if(connssl->encdata_buffer == NULL) {
+      failf(data, "schannel: unable to allocate memory");
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* if we need a bigger buffer to read a full message, increase buffer now */
+  if(connssl->encdata_length - connssl->encdata_offset <
+     CURL_SCHANNEL_BUFFER_FREE_SIZE) {
+    /* increase internal encrypted data buffer */
+    connssl->encdata_length *= CURL_SCHANNEL_BUFFER_STEP_FACTOR;
+    connssl->encdata_buffer = realloc(connssl->encdata_buffer,
+                                      connssl->encdata_length);
+
+    if(connssl->encdata_buffer == NULL) {
+      failf(data, "schannel: unable to re-allocate memory");
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  for(;;) {
+    if(doread) {
+      /* read encrypted handshake data from socket */
+      code = Curl_read_plain(conn->sock[sockindex],
+                (char *) (connssl->encdata_buffer + connssl->encdata_offset),
+                          connssl->encdata_length - connssl->encdata_offset,
+                          &nread);
+      if(code == CURLE_AGAIN) {
+        if(connssl->connecting_state != ssl_connect_2_writing)
+          connssl->connecting_state = ssl_connect_2_reading;
+        infof(data, "schannel: failed to receive handshake, "
+              "need more data\n");
+        return CURLE_OK;
+      }
+      else if((code != CURLE_OK) || (nread == 0)) {
+        failf(data, "schannel: failed to receive handshake, "
+              "SSL/TLS connection failed");
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+
+      /* increase encrypted data buffer offset */
+      connssl->encdata_offset += nread;
+    }
+
+    infof(data, "schannel: encrypted data buffer: offset %zu length %zu\n",
+        connssl->encdata_offset, connssl->encdata_length);
+
+    /* setup input buffers */
+    InitSecBuffer(&inbuf[0], SECBUFFER_TOKEN, malloc(connssl->encdata_offset),
+                  curlx_uztoul(connssl->encdata_offset));
+    InitSecBuffer(&inbuf[1], SECBUFFER_EMPTY, NULL, 0);
+    InitSecBufferDesc(&inbuf_desc, inbuf, 2);
+
+    /* setup output buffers */
+    InitSecBuffer(&outbuf[0], SECBUFFER_TOKEN, NULL, 0);
+    InitSecBuffer(&outbuf[1], SECBUFFER_ALERT, NULL, 0);
+    InitSecBufferDesc(&outbuf_desc, outbuf, 2);
+
+    if(inbuf[0].pvBuffer == NULL) {
+      failf(data, "schannel: unable to allocate memory");
+      return CURLE_OUT_OF_MEMORY;
+    }
+
+    /* copy received handshake data into input buffer */
+    memcpy(inbuf[0].pvBuffer, connssl->encdata_buffer,
+           connssl->encdata_offset);
+
+    host_name = Curl_convert_UTF8_to_tchar(conn->host.name);
+    if(!host_name)
+      return CURLE_OUT_OF_MEMORY;
+
+    /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa375924.aspx */
+
+    sspi_status = s_pSecFn->InitializeSecurityContext(
+      &connssl->cred->cred_handle, &connssl->ctxt->ctxt_handle,
+      host_name, connssl->req_flags, 0, 0, &inbuf_desc, 0, NULL,
+      &outbuf_desc, &connssl->ret_flags, &connssl->ctxt->time_stamp);
+
+    Curl_unicodefree(host_name);
+
+    /* free buffer for received handshake data */
+    Curl_safefree(inbuf[0].pvBuffer);
+
+    /* check if the handshake was incomplete */
+    if(sspi_status == SEC_E_INCOMPLETE_MESSAGE) {
+      connssl->connecting_state = ssl_connect_2_reading;
+      infof(data, "schannel: received incomplete message, need more data\n");
+      return CURLE_OK;
+    }
+
+    /* check if the handshake needs to be continued */
+    if(sspi_status == SEC_I_CONTINUE_NEEDED || sspi_status == SEC_E_OK) {
+      for(i = 0; i < 2; i++) {
+        /* search for handshake tokens that need to be send */
+        if(outbuf[i].BufferType == SECBUFFER_TOKEN && outbuf[i].cbBuffer > 0) {
+          infof(data, "schannel: sending next handshake data: "
+                "sending %lu bytes...\n", outbuf[i].cbBuffer);
+
+          /* send handshake token to server */
+          code = Curl_write_plain(conn, conn->sock[sockindex],
+                                  outbuf[i].pvBuffer, outbuf[i].cbBuffer,
+                                  &written);
+          if((code != CURLE_OK) || (outbuf[i].cbBuffer != (size_t)written)) {
+            failf(data, "schannel: failed to send next handshake data: "
+                  "sent %zd of %lu bytes", written, outbuf[i].cbBuffer);
+            return CURLE_SSL_CONNECT_ERROR;
+          }
+        }
+
+        /* free obsolete buffer */
+        if(outbuf[i].pvBuffer != NULL) {
+          s_pSecFn->FreeContextBuffer(outbuf[i].pvBuffer);
+        }
+      }
+    }
+    else {
+      if(sspi_status == SEC_E_WRONG_PRINCIPAL)
+        failf(data, "schannel: SNI or certificate check failed: %s",
+              Curl_sspi_strerror(conn, sspi_status));
+      else
+        failf(data, "schannel: next InitializeSecurityContext failed: %s",
+              Curl_sspi_strerror(conn, sspi_status));
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+
+    /* check if there was additional remaining encrypted data */
+    if(inbuf[1].BufferType == SECBUFFER_EXTRA && inbuf[1].cbBuffer > 0) {
+      infof(data, "schannel: encrypted data length: %lu\n", inbuf[1].cbBuffer);
+      /*
+         There are two cases where we could be getting extra data here:
+         1) If we're renegotiating a connection and the handshake is already
+            complete (from the server perspective), it can encrypted app data
+            (not handshake data) in an extra buffer at this point.
+         2) (sspi_status == SEC_I_CONTINUE_NEEDED) We are negotiating a
+            connection and this extra data is part of the handshake.
+            We should process the data immediately; waiting for the socket to
+            be ready may fail since the server is done sending handshake data.
+       */
+      /* check if the remaining data is less than the total amount
+         and therefore begins after the already processed data */
+      if(connssl->encdata_offset > inbuf[1].cbBuffer) {
+        memmove(connssl->encdata_buffer,
+                (connssl->encdata_buffer + connssl->encdata_offset) -
+                  inbuf[1].cbBuffer, inbuf[1].cbBuffer);
+        connssl->encdata_offset = inbuf[1].cbBuffer;
+        if(sspi_status == SEC_I_CONTINUE_NEEDED) {
+          doread = FALSE;
+          continue;
+        }
+      }
+    }
+    else {
+      connssl->encdata_offset = 0;
+    }
+    break;
+  }
+
+  /* check if the handshake needs to be continued */
+  if(sspi_status == SEC_I_CONTINUE_NEEDED) {
+    connssl->connecting_state = ssl_connect_2_reading;
+    return CURLE_OK;
+  }
+
+  /* check if the handshake is complete */
+  if(sspi_status == SEC_E_OK) {
+    connssl->connecting_state = ssl_connect_3;
+    infof(data, "schannel: SSL/TLS handshake complete\n");
+  }
+
+#ifdef _WIN32_WCE
+  /* Windows CE doesn't do any server certificate validation.
+     We have to do it manually. */
+  if(data->set.ssl.verifypeer)
+    return verify_certificate(conn, sockindex);
+#endif
+
+  return CURLE_OK;
+}
+
+static CURLcode
+schannel_connect_step3(struct connectdata *conn, int sockindex)
+{
+  CURLcode retcode = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct curl_schannel_cred *old_cred = NULL;
+  int incache;
+
+  DEBUGASSERT(ssl_connect_3 == connssl->connecting_state);
+
+  infof(data, "schannel: SSL/TLS connection with %s port %hu (step 3/3)\n",
+        conn->host.name, conn->remote_port);
+
+  /* check if the required context attributes are met */
+  if(connssl->ret_flags != connssl->req_flags) {
+    if(!(connssl->ret_flags & ISC_RET_SEQUENCE_DETECT))
+      failf(data, "schannel: failed to setup sequence detection");
+    if(!(connssl->ret_flags & ISC_RET_REPLAY_DETECT))
+      failf(data, "schannel: failed to setup replay detection");
+    if(!(connssl->ret_flags & ISC_RET_CONFIDENTIALITY))
+      failf(data, "schannel: failed to setup confidentiality");
+    if(!(connssl->ret_flags & ISC_RET_ALLOCATED_MEMORY))
+      failf(data, "schannel: failed to setup memory allocation");
+    if(!(connssl->ret_flags & ISC_RET_STREAM))
+      failf(data, "schannel: failed to setup stream orientation");
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+
+  /* increment the reference counter of the credential/session handle */
+  if(connssl->cred && connssl->ctxt) {
+    connssl->cred->refcount++;
+    infof(data, "schannel: incremented credential handle refcount = %d\n",
+          connssl->cred->refcount);
+  }
+
+  /* save the current session data for possible re-use */
+  incache = !(Curl_ssl_getsessionid(conn, (void**)&old_cred, NULL));
+  if(incache) {
+    if(old_cred != connssl->cred) {
+      infof(data, "schannel: old credential handle is stale, removing\n");
+      Curl_ssl_delsessionid(conn, (void*)old_cred);
+      incache = FALSE;
+    }
+  }
+  if(!incache) {
+    retcode = Curl_ssl_addsessionid(conn, (void*)connssl->cred,
+                                    sizeof(struct curl_schannel_cred));
+    if(retcode) {
+      failf(data, "schannel: failed to store credential handle");
+      return retcode;
+    }
+    else {
+      connssl->cred->cached = TRUE;
+      infof(data, "schannel: stored credential handle in session cache\n");
+    }
+  }
+
+  connssl->connecting_state = ssl_connect_done;
+
+  return CURLE_OK;
+}
+
+static CURLcode
+schannel_connect_common(struct connectdata *conn, int sockindex,
+                        bool nonblocking, bool *done)
+{
+  CURLcode retcode;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  curl_socket_t sockfd = conn->sock[sockindex];
+  long timeout_ms;
+  int what;
+
+  /* check if the connection has already been established */
+  if(ssl_connection_complete == connssl->state) {
+    *done = TRUE;
+    return CURLE_OK;
+  }
+
+  if(ssl_connect_1 == connssl->connecting_state) {
+    /* check out how much more time we're allowed */
+    timeout_ms = Curl_timeleft(data, NULL, TRUE);
+
+    if(timeout_ms < 0) {
+      /* no need to continue if time already is up */
+      failf(data, "SSL/TLS connection timeout");
+      return CURLE_OPERATION_TIMEDOUT;
+    }
+
+    retcode = schannel_connect_step1(conn, sockindex);
+    if(retcode)
+      return retcode;
+  }
+
+  while(ssl_connect_2 == connssl->connecting_state ||
+        ssl_connect_2_reading == connssl->connecting_state ||
+        ssl_connect_2_writing == connssl->connecting_state) {
+
+    /* check out how much more time we're allowed */
+    timeout_ms = Curl_timeleft(data, NULL, TRUE);
+
+    if(timeout_ms < 0) {
+      /* no need to continue if time already is up */
+      failf(data, "SSL/TLS connection timeout");
+      return CURLE_OPERATION_TIMEDOUT;
+    }
+
+    /* if ssl is expecting something, check if it's available. */
+    if(connssl->connecting_state == ssl_connect_2_reading
+       || connssl->connecting_state == ssl_connect_2_writing) {
+
+      curl_socket_t writefd = ssl_connect_2_writing ==
+        connssl->connecting_state ? sockfd : CURL_SOCKET_BAD;
+      curl_socket_t readfd = ssl_connect_2_reading ==
+        connssl->connecting_state ? sockfd : CURL_SOCKET_BAD;
+
+      what = Curl_socket_ready(readfd, writefd, nonblocking ? 0 : timeout_ms);
+      if(what < 0) {
+        /* fatal error */
+        failf(data, "select/poll on SSL/TLS socket, errno: %d", SOCKERRNO);
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      else if(0 == what) {
+        if(nonblocking) {
+          *done = FALSE;
+          return CURLE_OK;
+        }
+        else {
+          /* timeout */
+          failf(data, "SSL/TLS connection timeout");
+          return CURLE_OPERATION_TIMEDOUT;
+        }
+      }
+      /* socket is readable or writable */
+    }
+
+    /* Run transaction, and return to the caller if it failed or if
+     * this connection is part of a multi handle and this loop would
+     * execute again. This permits the owner of a multi handle to
+     * abort a connection attempt before step2 has completed while
+     * ensuring that a client using select() or epoll() will always
+     * have a valid fdset to wait on.
+     */
+    retcode = schannel_connect_step2(conn, sockindex);
+    if(retcode || (nonblocking &&
+                   (ssl_connect_2 == connssl->connecting_state ||
+                    ssl_connect_2_reading == connssl->connecting_state ||
+                    ssl_connect_2_writing == connssl->connecting_state)))
+      return retcode;
+
+  } /* repeat step2 until all transactions are done. */
+
+  if(ssl_connect_3 == connssl->connecting_state) {
+    retcode = schannel_connect_step3(conn, sockindex);
+    if(retcode)
+      return retcode;
+  }
+
+  if(ssl_connect_done == connssl->connecting_state) {
+    connssl->state = ssl_connection_complete;
+    conn->recv[sockindex] = schannel_recv;
+    conn->send[sockindex] = schannel_send;
+    *done = TRUE;
+  }
+  else
+    *done = FALSE;
+
+  /* reset our connection state machine */
+  connssl->connecting_state = ssl_connect_1;
+
+  return CURLE_OK;
+}
+
+static ssize_t
+schannel_send(struct connectdata *conn, int sockindex,
+              const void *buf, size_t len, CURLcode *err)
+{
+  ssize_t written = -1;
+  size_t data_len = 0;
+  unsigned char *data = NULL;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  SecBuffer outbuf[4];
+  SecBufferDesc outbuf_desc;
+  SECURITY_STATUS sspi_status = SEC_E_OK;
+  CURLcode code;
+
+  /* check if the maximum stream sizes were queried */
+  if(connssl->stream_sizes.cbMaximumMessage == 0) {
+    sspi_status = s_pSecFn->QueryContextAttributes(
+                              &connssl->ctxt->ctxt_handle,
+                              SECPKG_ATTR_STREAM_SIZES,
+                              &connssl->stream_sizes);
+    if(sspi_status != SEC_E_OK) {
+      *err = CURLE_SEND_ERROR;
+      return -1;
+    }
+  }
+
+  /* check if the buffer is longer than the maximum message length */
+  if(len > connssl->stream_sizes.cbMaximumMessage) {
+    *err = CURLE_SEND_ERROR;
+    return -1;
+  }
+
+  /* calculate the complete message length and allocate a buffer for it */
+  data_len = connssl->stream_sizes.cbHeader + len +
+              connssl->stream_sizes.cbTrailer;
+  data = (unsigned char*) malloc(data_len);
+  if(data == NULL) {
+    *err = CURLE_OUT_OF_MEMORY;
+    return -1;
+  }
+
+  /* setup output buffers (header, data, trailer, empty) */
+  InitSecBuffer(&outbuf[0], SECBUFFER_STREAM_HEADER,
+                data, connssl->stream_sizes.cbHeader);
+  InitSecBuffer(&outbuf[1], SECBUFFER_DATA,
+                data + connssl->stream_sizes.cbHeader, curlx_uztoul(len));
+  InitSecBuffer(&outbuf[2], SECBUFFER_STREAM_TRAILER,
+                data + connssl->stream_sizes.cbHeader + len,
+                connssl->stream_sizes.cbTrailer);
+  InitSecBuffer(&outbuf[3], SECBUFFER_EMPTY, NULL, 0);
+  InitSecBufferDesc(&outbuf_desc, outbuf, 4);
+
+  /* copy data into output buffer */
+  memcpy(outbuf[1].pvBuffer, buf, len);
+
+  /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa375390.aspx */
+  sspi_status = s_pSecFn->EncryptMessage(&connssl->ctxt->ctxt_handle, 0,
+                                         &outbuf_desc, 0);
+
+  /* check if the message was encrypted */
+  if(sspi_status == SEC_E_OK) {
+    written = 0;
+
+    /* send the encrypted message including header, data and trailer */
+    len = outbuf[0].cbBuffer + outbuf[1].cbBuffer + outbuf[2].cbBuffer;
+
+    /*
+       It's important to send the full message which includes the header,
+       encrypted payload, and trailer.  Until the client receives all the
+       data a coherent message has not been delivered and the client
+       can't read any of it.
+
+       If we wanted to buffer the unwritten encrypted bytes, we would
+       tell the client that all data it has requested to be sent has been
+       sent. The unwritten encrypted bytes would be the first bytes to
+       send on the next invocation.
+       Here's the catch with this - if we tell the client that all the
+       bytes have been sent, will the client call this method again to
+       send the buffered data?  Looking at who calls this function, it
+       seems the answer is NO.
+    */
+
+    /* send entire message or fail */
+    while(len > (size_t)written) {
+      ssize_t this_write;
+      long timeleft;
+      int what;
+
+      this_write = 0;
+
+      timeleft = Curl_timeleft(conn->data, NULL, TRUE);
+      if(timeleft < 0) {
+        /* we already got the timeout */
+        failf(conn->data, "schannel: timed out sending data "
+              "(bytes sent: %zd)", written);
+        *err = CURLE_OPERATION_TIMEDOUT;
+        written = -1;
+        break;
+      }
+
+      what = Curl_socket_ready(CURL_SOCKET_BAD, conn->sock[sockindex],
+                               timeleft);
+      if(what < 0) {
+        /* fatal error */
+        failf(conn->data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
+        *err = CURLE_SEND_ERROR;
+        written = -1;
+        break;
+      }
+      else if(0 == what) {
+        failf(conn->data, "schannel: timed out sending data "
+              "(bytes sent: %zd)", written);
+        *err = CURLE_OPERATION_TIMEDOUT;
+        written = -1;
+        break;
+      }
+      /* socket is writable */
+
+      code = Curl_write_plain(conn, conn->sock[sockindex], data + written,
+                              len - written, &this_write);
+      if(code == CURLE_AGAIN)
+        continue;
+      else if(code != CURLE_OK) {
+        *err = code;
+        written = -1;
+        break;
+      }
+
+      written += this_write;
+    }
+  }
+  else if(sspi_status == SEC_E_INSUFFICIENT_MEMORY) {
+    *err = CURLE_OUT_OF_MEMORY;
+  }
+  else{
+    *err = CURLE_SEND_ERROR;
+  }
+
+  Curl_safefree(data);
+
+  if(len == (size_t)written)
+    /* Encrypted message including header, data and trailer entirely sent.
+       The return value is the number of unencrypted bytes that were sent. */
+    written = outbuf[1].cbBuffer;
+
+  return written;
+}
+
+static ssize_t
+schannel_recv(struct connectdata *conn, int sockindex,
+              char *buf, size_t len, CURLcode *err)
+{
+  size_t size = 0;
+  ssize_t nread = 0, ret = -1;
+  CURLcode retcode;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  bool done = FALSE;
+  SecBuffer inbuf[4];
+  SecBufferDesc inbuf_desc;
+  SECURITY_STATUS sspi_status = SEC_E_OK;
+
+  infof(data, "schannel: client wants to read %zu bytes\n", len);
+  *err = CURLE_OK;
+
+  /* buffer to store previously received and decrypted data */
+  if(connssl->decdata_buffer == NULL) {
+    connssl->decdata_offset = 0;
+    connssl->decdata_length = CURL_SCHANNEL_BUFFER_INIT_SIZE;
+    connssl->decdata_buffer = malloc(connssl->decdata_length);
+    if(connssl->decdata_buffer == NULL) {
+      failf(data, "schannel: unable to allocate memory");
+      *err = CURLE_OUT_OF_MEMORY;
+      return -1;
+    }
+  }
+
+  /* increase buffer in order to fit the requested amount of data */
+  while(connssl->encdata_length - connssl->encdata_offset <
+        CURL_SCHANNEL_BUFFER_FREE_SIZE || connssl->encdata_length < len) {
+    /* increase internal encrypted data buffer */
+    connssl->encdata_length *= CURL_SCHANNEL_BUFFER_STEP_FACTOR;
+    connssl->encdata_buffer = realloc(connssl->encdata_buffer,
+                                      connssl->encdata_length);
+
+    if(connssl->encdata_buffer == NULL) {
+      failf(data, "schannel: unable to re-allocate memory");
+      *err = CURLE_OUT_OF_MEMORY;
+      return -1;
+    }
+  }
+
+  /* read encrypted data from socket */
+  infof(data, "schannel: encrypted data buffer: offset %zu length %zu\n",
+        connssl->encdata_offset, connssl->encdata_length);
+  size = connssl->encdata_length - connssl->encdata_offset;
+  if(size > 0) {
+    *err = Curl_read_plain(conn->sock[sockindex],
+                  (char *) (connssl->encdata_buffer + connssl->encdata_offset),
+                           size, &nread);
+    /* check for received data */
+    if(*err != CURLE_OK)
+      ret = -1;
+    else {
+      if(nread > 0)
+        /* increase encrypted data buffer offset */
+        connssl->encdata_offset += nread;
+      ret = nread;
+    }
+    infof(data, "schannel: encrypted data got %zd\n", ret);
+  }
+
+  infof(data, "schannel: encrypted data buffer: offset %zu length %zu\n",
+        connssl->encdata_offset, connssl->encdata_length);
+
+  /* check if we still have some data in our buffers */
+  while(connssl->encdata_offset > 0 && sspi_status == SEC_E_OK &&
+        connssl->decdata_offset < len) {
+    /* prepare data buffer for DecryptMessage call */
+    InitSecBuffer(&inbuf[0], SECBUFFER_DATA, connssl->encdata_buffer,
+                  curlx_uztoul(connssl->encdata_offset));
+
+    /* we need 3 more empty input buffers for possible output */
+    InitSecBuffer(&inbuf[1], SECBUFFER_EMPTY, NULL, 0);
+    InitSecBuffer(&inbuf[2], SECBUFFER_EMPTY, NULL, 0);
+    InitSecBuffer(&inbuf[3], SECBUFFER_EMPTY, NULL, 0);
+
+    InitSecBufferDesc(&inbuf_desc, inbuf, 4);
+
+    /* http://msdn.microsoft.com/en-us/library/windows/desktop/aa375348.aspx */
+    sspi_status = s_pSecFn->DecryptMessage(&connssl->ctxt->ctxt_handle,
+                                           &inbuf_desc, 0, NULL);
+
+    /* check if we need more data */
+    if(sspi_status == SEC_E_INCOMPLETE_MESSAGE) {
+      infof(data, "schannel: failed to decrypt data, need more data\n");
+      *err = CURLE_AGAIN;
+      return -1;
+    }
+
+    /* check if everything went fine (server may want to renegotiate
+       context) */
+    if(sspi_status == SEC_E_OK || sspi_status == SEC_I_RENEGOTIATE ||
+                                  sspi_status == SEC_I_CONTEXT_EXPIRED) {
+      /* check for successfully decrypted data */
+      if(inbuf[1].BufferType == SECBUFFER_DATA) {
+        infof(data, "schannel: decrypted data length: %lu\n",
+              inbuf[1].cbBuffer);
+
+        /* increase buffer in order to fit the received amount of data */
+        size = inbuf[1].cbBuffer > CURL_SCHANNEL_BUFFER_FREE_SIZE ?
+               inbuf[1].cbBuffer : CURL_SCHANNEL_BUFFER_FREE_SIZE;
+        while(connssl->decdata_length - connssl->decdata_offset < size ||
+              connssl->decdata_length < len) {
+          /* increase internal decrypted data buffer */
+          connssl->decdata_length *= CURL_SCHANNEL_BUFFER_STEP_FACTOR;
+          connssl->decdata_buffer = realloc(connssl->decdata_buffer,
+                                            connssl->decdata_length);
+
+          if(connssl->decdata_buffer == NULL) {
+            failf(data, "schannel: unable to re-allocate memory");
+            *err = CURLE_OUT_OF_MEMORY;
+            return -1;
+          }
+        }
+
+        /* copy decrypted data to internal buffer */
+        size = inbuf[1].cbBuffer;
+        if(size > 0) {
+          memcpy(connssl->decdata_buffer + connssl->decdata_offset,
+                 inbuf[1].pvBuffer, size);
+          connssl->decdata_offset += size;
+        }
+
+        infof(data, "schannel: decrypted data added: %zu\n", size);
+        infof(data, "schannel: decrypted data cached: offset %zu length %zu\n",
+              connssl->decdata_offset, connssl->decdata_length);
+      }
+
+      /* check for remaining encrypted data */
+      if(inbuf[3].BufferType == SECBUFFER_EXTRA && inbuf[3].cbBuffer > 0) {
+        infof(data, "schannel: encrypted data length: %lu\n",
+              inbuf[3].cbBuffer);
+
+        /* check if the remaining data is less than the total amount
+         * and therefore begins after the already processed data
+        */
+        if(connssl->encdata_offset > inbuf[3].cbBuffer) {
+          /* move remaining encrypted data forward to the beginning of
+             buffer */
+          memmove(connssl->encdata_buffer,
+                  (connssl->encdata_buffer + connssl->encdata_offset) -
+                    inbuf[3].cbBuffer, inbuf[3].cbBuffer);
+          connssl->encdata_offset = inbuf[3].cbBuffer;
+        }
+
+        infof(data, "schannel: encrypted data cached: offset %zu length %zu\n",
+              connssl->encdata_offset, connssl->encdata_length);
+      }
+      else{
+        /* reset encrypted buffer offset, because there is no data remaining */
+        connssl->encdata_offset = 0;
+      }
+    }
+
+    /* check if server wants to renegotiate the connection context */
+    if(sspi_status == SEC_I_RENEGOTIATE) {
+      infof(data, "schannel: remote party requests SSL/TLS renegotiation\n");
+
+      /* begin renegotiation */
+      infof(data, "schannel: renegotiating SSL/TLS connection\n");
+      connssl->state = ssl_connection_negotiating;
+      connssl->connecting_state = ssl_connect_2_writing;
+      retcode = schannel_connect_common(conn, sockindex, FALSE, &done);
+      if(retcode)
+        *err = retcode;
+      else {
+        infof(data, "schannel: SSL/TLS connection renegotiated\n");
+        /* now retry receiving data */
+        return schannel_recv(conn, sockindex, buf, len, err);
+      }
+    }
+  }
+
+  infof(data, "schannel: decrypted data buffer: offset %zu length %zu\n",
+        connssl->decdata_offset, connssl->decdata_length);
+
+  /* copy requested decrypted data to supplied buffer */
+  size = len < connssl->decdata_offset ? len : connssl->decdata_offset;
+  if(size > 0) {
+    memcpy(buf, connssl->decdata_buffer, size);
+    ret = size;
+
+    /* move remaining decrypted data forward to the beginning of buffer */
+    memmove(connssl->decdata_buffer, connssl->decdata_buffer + size,
+            connssl->decdata_offset - size);
+    connssl->decdata_offset -= size;
+
+    infof(data, "schannel: decrypted data returned %zd\n", size);
+    infof(data, "schannel: decrypted data buffer: offset %zu length %zu\n",
+          connssl->decdata_offset, connssl->decdata_length);
+  }
+
+  /* check if the server closed the connection */
+  if(ret <= 0 && ( /* special check for Windows 2000 Professional */
+      sspi_status == SEC_I_CONTEXT_EXPIRED || (sspi_status == SEC_E_OK &&
+        connssl->encdata_offset > 0 && connssl->encdata_buffer[0] == 0x15))) {
+    infof(data, "schannel: server closed the connection\n");
+    *err = CURLE_OK;
+    return 0;
+  }
+
+  /* check if something went wrong and we need to return an error */
+  if(ret < 0 && sspi_status != SEC_E_OK) {
+    infof(data, "schannel: failed to read data from server: %s\n",
+          Curl_sspi_strerror(conn, sspi_status));
+    *err = CURLE_RECV_ERROR;
+    return -1;
+  }
+
+  return ret;
+}
+
+CURLcode
+Curl_schannel_connect_nonblocking(struct connectdata *conn, int sockindex,
+                                  bool *done)
+{
+  return schannel_connect_common(conn, sockindex, TRUE, done);
+}
+
+CURLcode
+Curl_schannel_connect(struct connectdata *conn, int sockindex)
+{
+  CURLcode retcode;
+  bool done = FALSE;
+
+  retcode = schannel_connect_common(conn, sockindex, FALSE, &done);
+  if(retcode)
+    return retcode;
+
+  DEBUGASSERT(done);
+
+  return CURLE_OK;
+}
+
+bool Curl_schannel_data_pending(const struct connectdata *conn, int sockindex)
+{
+  const struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+
+  if(connssl->use) /* SSL/TLS is in use */
+    return (connssl->encdata_offset > 0 ||
+            connssl->decdata_offset > 0 ) ? TRUE : FALSE;
+  else
+    return FALSE;
+}
+
+void Curl_schannel_close(struct connectdata *conn, int sockindex)
+{
+  if(conn->ssl[sockindex].use)
+    /* if the SSL/TLS channel hasn't been shut down yet, do that now. */
+    Curl_ssl_shutdown(conn, sockindex);
+}
+
+int Curl_schannel_shutdown(struct connectdata *conn, int sockindex)
+{
+  /* See http://msdn.microsoft.com/en-us/library/windows/desktop/aa380138.aspx
+   * Shutting Down an Schannel Connection
+   */
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+
+  infof(data, "schannel: shutting down SSL/TLS connection with %s port %hu\n",
+        conn->host.name, conn->remote_port);
+
+  if(connssl->cred && connssl->ctxt) {
+    SecBufferDesc BuffDesc;
+    SecBuffer Buffer;
+    SECURITY_STATUS sspi_status;
+    SecBuffer outbuf;
+    SecBufferDesc outbuf_desc;
+    CURLcode code;
+    TCHAR *host_name;
+    DWORD dwshut = SCHANNEL_SHUTDOWN;
+
+    InitSecBuffer(&Buffer, SECBUFFER_TOKEN, &dwshut, sizeof(dwshut));
+    InitSecBufferDesc(&BuffDesc, &Buffer, 1);
+
+    sspi_status = s_pSecFn->ApplyControlToken(&connssl->ctxt->ctxt_handle,
+                                              &BuffDesc);
+
+    if(sspi_status != SEC_E_OK)
+      failf(data, "schannel: ApplyControlToken failure: %s",
+            Curl_sspi_strerror(conn, sspi_status));
+
+    host_name = Curl_convert_UTF8_to_tchar(conn->host.name);
+    if(!host_name)
+      return CURLE_OUT_OF_MEMORY;
+
+    /* setup output buffer */
+    InitSecBuffer(&outbuf, SECBUFFER_EMPTY, NULL, 0);
+    InitSecBufferDesc(&outbuf_desc, &outbuf, 1);
+
+    sspi_status = s_pSecFn->InitializeSecurityContext(
+         &connssl->cred->cred_handle,
+         &connssl->ctxt->ctxt_handle,
+         host_name,
+         connssl->req_flags,
+         0,
+         0,
+         NULL,
+         0,
+         &connssl->ctxt->ctxt_handle,
+         &outbuf_desc,
+         &connssl->ret_flags,
+         &connssl->ctxt->time_stamp);
+
+    Curl_unicodefree(host_name);
+
+    if((sspi_status == SEC_E_OK) || (sspi_status == SEC_I_CONTEXT_EXPIRED)) {
+      /* send close message which is in output buffer */
+      ssize_t written;
+      code = Curl_write_plain(conn, conn->sock[sockindex], outbuf.pvBuffer,
+                              outbuf.cbBuffer, &written);
+
+      s_pSecFn->FreeContextBuffer(outbuf.pvBuffer);
+      if((code != CURLE_OK) || (outbuf.cbBuffer != (size_t)written)) {
+        infof(data, "schannel: failed to send close msg: %s"
+              " (bytes written: %zd)\n", curl_easy_strerror(code), written);
+      }
+    }
+
+    /* free SSPI Schannel API security context handle */
+    if(connssl->ctxt) {
+      infof(data, "schannel: clear security context handle\n");
+      s_pSecFn->DeleteSecurityContext(&connssl->ctxt->ctxt_handle);
+      Curl_safefree(connssl->ctxt);
+    }
+
+    /* free SSPI Schannel API credential handle */
+    if(connssl->cred) {
+      /* decrement the reference counter of the credential/session handle */
+      if(connssl->cred->refcount > 0) {
+        connssl->cred->refcount--;
+        infof(data, "schannel: decremented credential handle refcount = %d\n",
+              connssl->cred->refcount);
+      }
+
+      /* if the handle was not cached and the refcount is zero */
+      if(!connssl->cred->cached && connssl->cred->refcount == 0) {
+        infof(data, "schannel: clear credential handle\n");
+        s_pSecFn->FreeCredentialsHandle(&connssl->cred->cred_handle);
+        Curl_safefree(connssl->cred);
+      }
+    }
+  }
+
+  /* free internal buffer for received encrypted data */
+  if(connssl->encdata_buffer != NULL) {
+    Curl_safefree(connssl->encdata_buffer);
+    connssl->encdata_length = 0;
+    connssl->encdata_offset = 0;
+  }
+
+  /* free internal buffer for received decrypted data */
+  if(connssl->decdata_buffer != NULL) {
+    Curl_safefree(connssl->decdata_buffer);
+    connssl->decdata_length = 0;
+    connssl->decdata_offset = 0;
+  }
+
+  return CURLE_OK;
+}
+
+void Curl_schannel_session_free(void *ptr)
+{
+  struct curl_schannel_cred *cred = ptr;
+
+  if(cred && cred->cached && cred->refcount == 0) {
+    s_pSecFn->FreeCredentialsHandle(&cred->cred_handle);
+    Curl_safefree(cred);
+  }
+}
+
+int Curl_schannel_init(void)
+{
+  return (Curl_sspi_global_init() == CURLE_OK ? 1 : 0);
+}
+
+void Curl_schannel_cleanup(void)
+{
+  Curl_sspi_global_cleanup();
+}
+
+size_t Curl_schannel_version(char *buffer, size_t size)
+{
+  size = snprintf(buffer, size, "WinSSL");
+
+  return size;
+}
+
+#ifdef _WIN32_WCE
+static CURLcode verify_certificate(struct connectdata *conn, int sockindex)
+{
+  SECURITY_STATUS status;
+  struct SessionHandle *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  CURLcode result = CURLE_OK;
+  CERT_CONTEXT *pCertContextServer = NULL;
+  const CERT_CHAIN_CONTEXT *pChainContext = NULL;
+
+  status = s_pSecFn->QueryContextAttributes(&connssl->ctxt->ctxt_handle,
+                                            SECPKG_ATTR_REMOTE_CERT_CONTEXT,
+                                            &pCertContextServer);
+
+  if((status != SEC_E_OK) || (pCertContextServer == NULL)) {
+    failf(data, "schannel: Failed to read remote certificate context: %s",
+          Curl_sspi_strerror(conn, status));
+    result = CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  if(result == CURLE_OK) {
+    CERT_CHAIN_PARA ChainPara;
+    memset(&ChainPara, 0, sizeof(ChainPara));
+    ChainPara.cbSize = sizeof(ChainPara);
+
+    if(!CertGetCertificateChain(NULL,
+                                pCertContextServer,
+                                NULL,
+                                pCertContextServer->hCertStore,
+                                &ChainPara,
+                                0,
+                                NULL,
+                                &pChainContext)) {
+      failf(data, "schannel: CertGetCertificateChain failed: %s",
+            Curl_sspi_strerror(conn, GetLastError()));
+      pChainContext = NULL;
+      result = CURLE_PEER_FAILED_VERIFICATION;
+    }
+
+    if(result == CURLE_OK) {
+      CERT_SIMPLE_CHAIN *pSimpleChain = pChainContext->rgpChain[0];
+      DWORD dwTrustErrorMask = ~(DWORD)(CERT_TRUST_IS_NOT_TIME_NESTED|
+                                 CERT_TRUST_REVOCATION_STATUS_UNKNOWN);
+      dwTrustErrorMask &= pSimpleChain->TrustStatus.dwErrorStatus;
+      if(dwTrustErrorMask) {
+        if(dwTrustErrorMask & CERT_TRUST_IS_PARTIAL_CHAIN)
+          failf(data, "schannel: CertGetCertificateChain trust error"
+                      " CERT_TRUST_IS_PARTIAL_CHAIN");
+        if(dwTrustErrorMask & CERT_TRUST_IS_UNTRUSTED_ROOT)
+          failf(data, "schannel: CertGetCertificateChain trust error"
+                      " CERT_TRUST_IS_UNTRUSTED_ROOT");
+        if(dwTrustErrorMask & CERT_TRUST_IS_NOT_TIME_VALID)
+          failf(data, "schannel: CertGetCertificateChain trust error"
+                      " CERT_TRUST_IS_NOT_TIME_VALID");
+        failf(data, "schannel: CertGetCertificateChain error mask: 0x%08x",
+              dwTrustErrorMask);
+        result = CURLE_PEER_FAILED_VERIFICATION;
+      }
+    }
+  }
+
+  if(result == CURLE_OK) {
+    if(data->set.ssl.verifyhost) {
+      TCHAR cert_hostname_buff[128];
+      xcharp_u hostname;
+      xcharp_u cert_hostname;
+      DWORD len;
+
+      cert_hostname.const_tchar_ptr = cert_hostname_buff;
+      hostname.tchar_ptr = Curl_convert_UTF8_to_tchar(conn->host.name);
+
+      len = CertGetNameString(pCertContextServer,
+                              CERT_NAME_DNS_TYPE,
+                              0,
+                              NULL,
+                              cert_hostname.tchar_ptr,
+                              128);
+      if(len > 0 && *cert_hostname.tchar_ptr == '*') {
+        /* this is a wildcard cert.  try matching the last len - 1 chars */
+        int hostname_len = strlen(conn->host.name);
+        cert_hostname.tchar_ptr++;
+        if(_tcsicmp(cert_hostname.const_tchar_ptr,
+                    hostname.const_tchar_ptr + hostname_len - len + 2) != 0)
+          result = CURLE_PEER_FAILED_VERIFICATION;
+      }
+      else if(len == 0 || _tcsicmp(hostname.const_tchar_ptr,
+                                   cert_hostname.const_tchar_ptr) != 0) {
+        result = CURLE_PEER_FAILED_VERIFICATION;
+      }
+      if(result == CURLE_PEER_FAILED_VERIFICATION) {
+        char *_cert_hostname;
+        _cert_hostname = Curl_convert_tchar_to_UTF8(cert_hostname.tchar_ptr);
+        failf(data, "schannel: CertGetNameString() certificate hostname "
+              "(%s) did not match connection (%s)",
+              _cert_hostname, conn->host.name);
+        Curl_unicodefree(_cert_hostname);
+      }
+      Curl_unicodefree(hostname.tchar_ptr);
+    }
+  }
+
+  if(pChainContext)
+    CertFreeCertificateChain(pChainContext);
+
+  if(pCertContextServer)
+    CertFreeCertificateContext(pCertContextServer);
+
+  return result;
+}
+#endif /* _WIN32_WCE */
+
+#endif /* USE_SCHANNEL */