/***************************************************************************
 *                                  _   _ ____  _     
 *  Project                     ___| | | |  _ \| |    
 *                             / __| | | | |_) | |    
 *                            | (__| |_| |  _ <| |___ 
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2003, 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.
 *
 * $Id$
 ***************************************************************************/
#include "setup.h"

#ifdef GSSAPI

#ifndef CURL_DISABLE_HTTP
/* -- WIN32 approved -- */
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>

#include "urldata.h"
#include "sendf.h"
#include "strequal.h"
#include "base64.h"
#include "http_negotiate.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

/* The last #include file should be: */
#ifdef CURLDEBUG
#include "memdebug.h"
#endif

static int
get_gss_name(struct connectdata *conn, gss_name_t *server)
{
  OM_uint32 major_status, minor_status;
  gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
  char name[2048];

  /* GSSAPI implementation by Globus (known as GSI) requires the name to be
     of form "<service>/<fqdn>" instead of <service>@<fqdn> (ie. slash instead
     of at-sign). Also GSI servers are often identified as 'host' not 'khttp'.
     Change following lines if you want to use GSI */
  token.length = strlen("khttp@") + strlen(conn->hostname) + 1;
  if (token.length + 1 > sizeof(name))
    return EMSGSIZE;
  sprintf(name, "khttp@%s", conn->hostname);

  token.value = (void *) name;
  major_status = gss_import_name(&minor_status,
                                 &token,
                                 GSS_C_NT_HOSTBASED_SERVICE,
                                 server);
  return GSS_ERROR(major_status) ? -1 : 0;
}

static void
log_gss_error(struct connectdata *conn, OM_uint32 error_status, char *prefix)
{
  OM_uint32 maj_stat, min_stat;
  OM_uint32 msg_ctx = 0;
  gss_buffer_desc status_string;
  char buf[1024];
  size_t len;

  snprintf(buf, sizeof(buf), "%s", prefix);
  len = strlen(buf);
  do {
    maj_stat = gss_display_status (&min_stat,
                                   error_status,
                                   GSS_C_MECH_CODE,
                                   GSS_C_NO_OID,
                                   &msg_ctx,
                                   &status_string);
    if (sizeof(buf) > len + status_string.length + 1) {
      sprintf(buf + len, ": %s", (char*) status_string.value);
      len += status_string.length;
    }
    gss_release_buffer(&min_stat, &status_string);
  } while (!GSS_ERROR(maj_stat) && msg_ctx != 0);

  infof(conn->data, buf);
}

int Curl_input_negotiate(struct connectdata *conn, char *header)
{ 
  struct negotiatedata *neg_ctx = &conn->data->state.negotiate;
  OM_uint32 major_status, minor_status, minor_status2;
  gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
  gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
  int ret;
  size_t len;

  while(*header && isspace((int)*header))
    header++;
  if(!checkprefix("GSS-Negotiate", header))
    return -1;

  if (neg_ctx->context && neg_ctx->status == GSS_S_COMPLETE) {
    /* We finished succesfully our part of authentication, but server
     * rejected it (since we're again here). Exit with an error since we
     * can't invent anything better */
    Curl_cleanup_negotiate(conn->data);
    return -1;
  }

  if (neg_ctx->server_name == NULL &&
      (ret = get_gss_name(conn, &neg_ctx->server_name)))
    return ret;

  header += strlen("GSS-Negotiate");
  while(*header && isspace((int)*header))
    header++;

  len = strlen(header);
  if (len > 0) {
    int rawlen;
    input_token.length = (len+3)/4 * 3;
    input_token.value = malloc(input_token.length);
    if (input_token.value == NULL)
      return ENOMEM;
    rawlen = Curl_base64_decode(header, input_token.value);
    if (rawlen < 0)
      return -1;
    input_token.length = rawlen;
  }

  major_status = gss_init_sec_context(&minor_status,
                                      GSS_C_NO_CREDENTIAL,
                                      &neg_ctx->context,
                                      neg_ctx->server_name,
                                      GSS_C_NO_OID,
                                      GSS_C_DELEG_FLAG,
                                      0,
                                      GSS_C_NO_CHANNEL_BINDINGS,
                                      &input_token,
                                      NULL,
                                      &output_token,
                                      NULL,
                                      NULL);
  if (input_token.length > 0)
    gss_release_buffer(&minor_status2, &input_token);
  neg_ctx->status = major_status;
  if (GSS_ERROR(major_status)) {
    /* Curl_cleanup_negotiate(conn->data) ??? */
    log_gss_error(conn, minor_status,
                  (char *)"gss_init_sec_context() failed: ");
    return -1;
  }

  if (output_token.length == 0) {
    return -1;
  }

  neg_ctx->output_token = output_token;
  /* conn->bits.close = FALSE; */

  return 0;
}
   

CURLcode Curl_output_negotiate(struct connectdata *conn)
{ 
  struct negotiatedata *neg_ctx = &conn->data->state.negotiate;
  OM_uint32 minor_status;
  char *encoded = NULL;
  int len = Curl_base64_encode(neg_ctx->output_token.value,
                               neg_ctx->output_token.length,
                               &encoded);
  if (len < 0)
    return CURLE_OUT_OF_MEMORY;

  conn->allocptr.userpwd =
    aprintf("Authorization: GSS-Negotiate %s\r\n", encoded);
  free(encoded);
  gss_release_buffer(&minor_status, &neg_ctx->output_token);
  return (conn->allocptr.userpwd == NULL) ? CURLE_OUT_OF_MEMORY : CURLE_OK;
}

void Curl_cleanup_negotiate(struct SessionHandle *data)
{ 
  OM_uint32 minor_status;
  struct negotiatedata *neg_ctx = &data->state.negotiate;

  if (neg_ctx->context != GSS_C_NO_CONTEXT)
    gss_delete_sec_context(&minor_status, &neg_ctx->context, GSS_C_NO_BUFFER);

  if (neg_ctx->output_token.length != 0)
    gss_release_buffer(&minor_status, &neg_ctx->output_token);

  if (neg_ctx->server_name != GSS_C_NO_NAME)
    gss_release_name(&minor_status, &neg_ctx->server_name);
  
  memset(neg_ctx, 0, sizeof(*neg_ctx));
}


#endif
#endif