322 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			322 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			C
		
	
	
	
| /***************************************************************************
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|  *                                  _   _ ____  _
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|  *  Project                     ___| | | |  _ \| |
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|  *                             / __| | | | |_) | |
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|  *                            | (__| |_| |  _ <| |___
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|  *                             \___|\___/|_| \_\_____|
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|  *
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|  * Copyright (C) 2014 - 2019, Steve Holme, <steve_holme@hotmail.com>.
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|  * Copyright (C) 2015 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
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|  *
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|  * This software is licensed as described in the file COPYING, which
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|  * you should have received as part of this distribution. The terms
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|  * are also available at https://curl.se/docs/copyright.html.
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|  *
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|  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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|  * copies of the Software, and permit persons to whom the Software is
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|  * furnished to do so, under the terms of the COPYING file.
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|  *
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|  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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|  * KIND, either express or implied.
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|  *
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|  * RFC4752 The Kerberos V5 ("GSSAPI") SASL Mechanism
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|  *
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|  ***************************************************************************/
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| 
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| #include "curl_setup.h"
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| 
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| #if defined(HAVE_GSSAPI) && defined(USE_KERBEROS5)
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| 
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| #include <curl/curl.h>
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| 
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| #include "vauth/vauth.h"
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| #include "curl_sasl.h"
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| #include "urldata.h"
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| #include "curl_gssapi.h"
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| #include "sendf.h"
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| #include "curl_printf.h"
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| 
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| /* The last #include files should be: */
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| #include "curl_memory.h"
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| #include "memdebug.h"
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| 
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| /*
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|  * Curl_auth_is_gssapi_supported()
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|  *
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|  * This is used to evaluate if GSSAPI (Kerberos V5) is supported.
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|  *
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|  * Parameters: None
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|  *
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|  * Returns TRUE if Kerberos V5 is supported by the GSS-API library.
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|  */
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| bool Curl_auth_is_gssapi_supported(void)
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| {
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|   return TRUE;
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| }
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| 
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| /*
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|  * Curl_auth_create_gssapi_user_message()
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|  *
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|  * This is used to generate an already encoded GSSAPI (Kerberos V5) user token
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|  * message ready for sending to the recipient.
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|  *
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|  * Parameters:
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|  *
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|  * data        [in]     - The session handle.
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|  * userp       [in]     - The user name.
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|  * passwdp     [in]     - The user's password.
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|  * service     [in]     - The service type such as http, smtp, pop or imap.
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|  * host        [in[     - The host name.
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|  * mutual_auth [in]     - Flag specifying whether or not mutual authentication
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|  *                        is enabled.
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|  * chlg        [in]     - Optional challenge message.
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|  * krb5        [in/out] - The Kerberos 5 data struct being used and modified.
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|  * out         [out]    - The result storage.
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|  *
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|  * Returns CURLE_OK on success.
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|  */
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| CURLcode Curl_auth_create_gssapi_user_message(struct Curl_easy *data,
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|                                               const char *userp,
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|                                               const char *passwdp,
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|                                               const char *service,
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|                                               const char *host,
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|                                               const bool mutual_auth,
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|                                               const struct bufref *chlg,
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|                                               struct kerberos5data *krb5,
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|                                               struct bufref *out)
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| {
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|   CURLcode result = CURLE_OK;
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|   OM_uint32 major_status;
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|   OM_uint32 minor_status;
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|   OM_uint32 unused_status;
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|   gss_buffer_desc spn_token = GSS_C_EMPTY_BUFFER;
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|   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
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|   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
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| 
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|   (void) userp;
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|   (void) passwdp;
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| 
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|   if(!krb5->spn) {
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|     /* Generate our SPN */
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|     char *spn = Curl_auth_build_spn(service, NULL, host);
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|     if(!spn)
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|       return CURLE_OUT_OF_MEMORY;
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| 
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|     /* Populate the SPN structure */
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|     spn_token.value = spn;
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|     spn_token.length = strlen(spn);
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| 
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|     /* Import the SPN */
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|     major_status = gss_import_name(&minor_status, &spn_token,
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|                                    GSS_C_NT_HOSTBASED_SERVICE, &krb5->spn);
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|     if(GSS_ERROR(major_status)) {
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|       Curl_gss_log_error(data, "gss_import_name() failed: ",
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|                          major_status, minor_status);
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| 
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|       free(spn);
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| 
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|       return CURLE_AUTH_ERROR;
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|     }
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| 
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|     free(spn);
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|   }
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| 
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|   if(chlg) {
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|     if(!Curl_bufref_len(chlg)) {
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|       infof(data, "GSSAPI handshake failure (empty challenge message)");
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|       return CURLE_BAD_CONTENT_ENCODING;
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|     }
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|     input_token.value = (void *) Curl_bufref_ptr(chlg);
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|     input_token.length = Curl_bufref_len(chlg);
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|   }
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| 
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|   major_status = Curl_gss_init_sec_context(data,
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|                                            &minor_status,
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|                                            &krb5->context,
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|                                            krb5->spn,
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|                                            &Curl_krb5_mech_oid,
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|                                            GSS_C_NO_CHANNEL_BINDINGS,
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|                                            &input_token,
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|                                            &output_token,
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|                                            mutual_auth,
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|                                            NULL);
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| 
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|   if(GSS_ERROR(major_status)) {
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|     if(output_token.value)
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|       gss_release_buffer(&unused_status, &output_token);
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| 
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|     Curl_gss_log_error(data, "gss_init_sec_context() failed: ",
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|                        major_status, minor_status);
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| 
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|     return CURLE_AUTH_ERROR;
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|   }
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| 
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|   if(output_token.value && output_token.length) {
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|     result = Curl_bufref_memdup(out, output_token.value, output_token.length);
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|     gss_release_buffer(&unused_status, &output_token);
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|   }
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|   else
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|     Curl_bufref_set(out, mutual_auth? "": NULL, 0, NULL);
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| 
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|   return result;
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| }
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| 
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| /*
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|  * Curl_auth_create_gssapi_security_message()
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|  *
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|  * This is used to generate an already encoded GSSAPI (Kerberos V5) security
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|  * token message ready for sending to the recipient.
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|  *
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|  * Parameters:
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|  *
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|  * data    [in]     - The session handle.
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|  * authzid [in]     - The authorization identity if some.
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|  * chlg    [in]     - Optional challenge message.
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|  * krb5    [in/out] - The Kerberos 5 data struct being used and modified.
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|  * out     [out]    - The result storage.
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|  *
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|  * Returns CURLE_OK on success.
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|  */
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| CURLcode Curl_auth_create_gssapi_security_message(struct Curl_easy *data,
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|                                                   const char *authzid,
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|                                                   const struct bufref *chlg,
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|                                                   struct kerberos5data *krb5,
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|                                                   struct bufref *out)
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| {
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|   CURLcode result = CURLE_OK;
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|   size_t messagelen = 0;
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|   unsigned char *message = NULL;
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|   OM_uint32 major_status;
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|   OM_uint32 minor_status;
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|   OM_uint32 unused_status;
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|   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
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|   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
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|   unsigned char *indata;
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|   gss_qop_t qop = GSS_C_QOP_DEFAULT;
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|   unsigned int sec_layer = 0;
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|   unsigned int max_size = 0;
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| 
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|   /* Ensure we have a valid challenge message */
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|   if(!Curl_bufref_len(chlg)) {
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|     infof(data, "GSSAPI handshake failure (empty security message)");
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|     return CURLE_BAD_CONTENT_ENCODING;
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|   }
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| 
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|   /* Setup the challenge "input" security buffer */
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|   input_token.value = (void *) Curl_bufref_ptr(chlg);
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|   input_token.length = Curl_bufref_len(chlg);
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| 
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|   /* Decrypt the inbound challenge and obtain the qop */
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|   major_status = gss_unwrap(&minor_status, krb5->context, &input_token,
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|                             &output_token, NULL, &qop);
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|   if(GSS_ERROR(major_status)) {
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|     Curl_gss_log_error(data, "gss_unwrap() failed: ",
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|                        major_status, minor_status);
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|     return CURLE_BAD_CONTENT_ENCODING;
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|   }
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| 
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|   /* Not 4 octets long so fail as per RFC4752 Section 3.1 */
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|   if(output_token.length != 4) {
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|     infof(data, "GSSAPI handshake failure (invalid security data)");
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|     return CURLE_BAD_CONTENT_ENCODING;
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|   }
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| 
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|   /* Extract the security layer and the maximum message size */
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|   indata = output_token.value;
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|   sec_layer = indata[0];
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|   max_size = (indata[1] << 16) | (indata[2] << 8) | indata[3];
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| 
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|   /* Free the challenge as it is not required anymore */
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|   gss_release_buffer(&unused_status, &output_token);
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| 
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|   /* Process the security layer */
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|   if(!(sec_layer & GSSAUTH_P_NONE)) {
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|     infof(data, "GSSAPI handshake failure (invalid security layer)");
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| 
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|     return CURLE_BAD_CONTENT_ENCODING;
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|   }
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|   sec_layer &= GSSAUTH_P_NONE;  /* We do not support a security layer */
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| 
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|   /* Process the maximum message size the server can receive */
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|   if(max_size > 0) {
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|     /* The server has told us it supports a maximum receive buffer, however, as
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|        we don't require one unless we are encrypting data, we tell the server
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|        our receive buffer is zero. */
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|     max_size = 0;
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|   }
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| 
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|   /* Allocate our message */
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|   messagelen = 4;
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|   if(authzid)
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|     messagelen += strlen(authzid);
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|   message = malloc(messagelen);
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|   if(!message)
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|     return CURLE_OUT_OF_MEMORY;
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| 
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|   /* Populate the message with the security layer and client supported receive
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|      message size. */
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|   message[0] = sec_layer & 0xFF;
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|   message[1] = (max_size >> 16) & 0xFF;
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|   message[2] = (max_size >> 8) & 0xFF;
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|   message[3] = max_size & 0xFF;
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| 
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|   /* If given, append the authorization identity. */
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| 
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|   if(authzid && *authzid)
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|     memcpy(message + 4, authzid, messagelen - 4);
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| 
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|   /* Setup the "authentication data" security buffer */
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|   input_token.value = message;
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|   input_token.length = messagelen;
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| 
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|   /* Encrypt the data */
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|   major_status = gss_wrap(&minor_status, krb5->context, 0,
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|                           GSS_C_QOP_DEFAULT, &input_token, NULL,
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|                           &output_token);
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|   if(GSS_ERROR(major_status)) {
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|     Curl_gss_log_error(data, "gss_wrap() failed: ",
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|                        major_status, minor_status);
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|     free(message);
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|     return CURLE_AUTH_ERROR;
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|   }
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| 
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|   /* Return the response. */
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|   result = Curl_bufref_memdup(out, output_token.value, output_token.length);
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|   /* Free the output buffer */
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|   gss_release_buffer(&unused_status, &output_token);
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| 
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|   /* Free the message buffer */
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|   free(message);
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| 
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|   return result;
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| }
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| 
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| /*
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|  * Curl_auth_cleanup_gssapi()
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|  *
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|  * This is used to clean up the GSSAPI (Kerberos V5) specific data.
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|  *
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|  * Parameters:
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|  *
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|  * krb5     [in/out] - The Kerberos 5 data struct being cleaned up.
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|  *
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|  */
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| void Curl_auth_cleanup_gssapi(struct kerberos5data *krb5)
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| {
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|   OM_uint32 minor_status;
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| 
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|   /* Free our security context */
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|   if(krb5->context != GSS_C_NO_CONTEXT) {
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|     gss_delete_sec_context(&minor_status, &krb5->context, GSS_C_NO_BUFFER);
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|     krb5->context = GSS_C_NO_CONTEXT;
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|   }
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| 
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|   /* Free the SPN */
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|   if(krb5->spn != GSS_C_NO_NAME) {
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|     gss_release_name(&minor_status, &krb5->spn);
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|     krb5->spn = GSS_C_NO_NAME;
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|   }
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| }
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| 
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| #endif /* HAVE_GSSAPI && USE_KERBEROS5 */
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