476 lines
15 KiB
C
476 lines
15 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) Steve Holme, <steve_holme@hotmail.com>.
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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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* SPDX-License-Identifier: curl
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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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#include "curl_setup.h"
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#if defined(USE_WINDOWS_SSPI) && defined(USE_KERBEROS5)
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#include <curl/curl.h>
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#include "vauth/vauth.h"
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#include "urldata.h"
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#include "warnless.h"
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#include "curl_multibyte.h"
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#include "sendf.h"
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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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* 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 Windows SSPI.
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*/
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bool Curl_auth_is_gssapi_supported(void)
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{
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PSecPkgInfo SecurityPackage;
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SECURITY_STATUS status;
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/* Query the security package for Kerberos */
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status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
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TEXT(SP_NAME_KERBEROS),
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&SecurityPackage);
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/* Release the package buffer as it is not required anymore */
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if(status == SEC_E_OK) {
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s_pSecFn->FreeContextBuffer(SecurityPackage);
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}
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return (status == SEC_E_OK ? TRUE : FALSE);
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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 in the format User or Domain\User.
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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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CtxtHandle context;
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PSecPkgInfo SecurityPackage;
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SecBuffer chlg_buf;
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SecBuffer resp_buf;
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SecBufferDesc chlg_desc;
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SecBufferDesc resp_desc;
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SECURITY_STATUS status;
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unsigned long attrs;
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TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
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if(!krb5->spn) {
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/* Generate our SPN */
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krb5->spn = Curl_auth_build_spn(service, host, NULL);
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if(!krb5->spn)
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return CURLE_OUT_OF_MEMORY;
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}
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if(!krb5->output_token) {
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/* Query the security package for Kerberos */
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status = s_pSecFn->QuerySecurityPackageInfo((TCHAR *)
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TEXT(SP_NAME_KERBEROS),
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&SecurityPackage);
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if(status != SEC_E_OK) {
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failf(data, "SSPI: couldn't get auth info");
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return CURLE_AUTH_ERROR;
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}
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krb5->token_max = SecurityPackage->cbMaxToken;
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/* Release the package buffer as it is not required anymore */
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s_pSecFn->FreeContextBuffer(SecurityPackage);
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/* Allocate our response buffer */
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krb5->output_token = malloc(krb5->token_max);
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if(!krb5->output_token)
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return CURLE_OUT_OF_MEMORY;
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}
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if(!krb5->credentials) {
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/* Do we have credentials to use or are we using single sign-on? */
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if(userp && *userp) {
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/* Populate our identity structure */
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result = Curl_create_sspi_identity(userp, passwdp, &krb5->identity);
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if(result)
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return result;
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/* Allow proper cleanup of the identity structure */
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krb5->p_identity = &krb5->identity;
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}
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else
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/* Use the current Windows user */
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krb5->p_identity = NULL;
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/* Allocate our credentials handle */
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krb5->credentials = calloc(1, sizeof(CredHandle));
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if(!krb5->credentials)
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return CURLE_OUT_OF_MEMORY;
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/* Acquire our credentials handle */
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status = s_pSecFn->AcquireCredentialsHandle(NULL,
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(TCHAR *)
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TEXT(SP_NAME_KERBEROS),
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SECPKG_CRED_OUTBOUND, NULL,
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krb5->p_identity, NULL, NULL,
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krb5->credentials, &expiry);
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if(status != SEC_E_OK)
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return CURLE_LOGIN_DENIED;
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/* Allocate our new context handle */
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krb5->context = calloc(1, sizeof(CtxtHandle));
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if(!krb5->context)
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return CURLE_OUT_OF_MEMORY;
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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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/* Setup the challenge "input" security buffer */
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chlg_desc.ulVersion = SECBUFFER_VERSION;
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chlg_desc.cBuffers = 1;
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chlg_desc.pBuffers = &chlg_buf;
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chlg_buf.BufferType = SECBUFFER_TOKEN;
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chlg_buf.pvBuffer = (void *) Curl_bufref_ptr(chlg);
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chlg_buf.cbBuffer = curlx_uztoul(Curl_bufref_len(chlg));
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}
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/* Setup the response "output" security buffer */
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resp_desc.ulVersion = SECBUFFER_VERSION;
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resp_desc.cBuffers = 1;
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resp_desc.pBuffers = &resp_buf;
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resp_buf.BufferType = SECBUFFER_TOKEN;
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resp_buf.pvBuffer = krb5->output_token;
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resp_buf.cbBuffer = curlx_uztoul(krb5->token_max);
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/* Generate our challenge-response message */
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status = s_pSecFn->InitializeSecurityContext(krb5->credentials,
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chlg ? krb5->context : NULL,
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krb5->spn,
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(mutual_auth ?
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ISC_REQ_MUTUAL_AUTH : 0),
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0, SECURITY_NATIVE_DREP,
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chlg ? &chlg_desc : NULL, 0,
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&context,
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&resp_desc, &attrs,
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&expiry);
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if(status == SEC_E_INSUFFICIENT_MEMORY)
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return CURLE_OUT_OF_MEMORY;
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if(status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED)
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return CURLE_AUTH_ERROR;
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if(memcmp(&context, krb5->context, sizeof(context))) {
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s_pSecFn->DeleteSecurityContext(krb5->context);
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memcpy(krb5->context, &context, sizeof(context));
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}
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if(resp_buf.cbBuffer) {
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result = Curl_bufref_memdup(out, resp_buf.pvBuffer, resp_buf.cbBuffer);
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}
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else if(mutual_auth)
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Curl_bufref_set(out, "", 0, NULL);
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else
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Curl_bufref_set(out, NULL, 0, NULL);
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return result;
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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] - The 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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size_t offset = 0;
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size_t messagelen = 0;
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size_t appdatalen = 0;
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unsigned char *trailer = NULL;
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unsigned char *message = NULL;
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unsigned char *padding = NULL;
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unsigned char *appdata = NULL;
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SecBuffer input_buf[2];
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SecBuffer wrap_buf[3];
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SecBufferDesc input_desc;
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SecBufferDesc wrap_desc;
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unsigned char *indata;
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unsigned long qop = 0;
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unsigned long sec_layer = 0;
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unsigned long max_size = 0;
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SecPkgContext_Sizes sizes;
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SECURITY_STATUS status;
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#if defined(CURL_DISABLE_VERBOSE_STRINGS)
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(void) data;
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#endif
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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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/* Get our response size information */
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status = s_pSecFn->QueryContextAttributes(krb5->context,
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SECPKG_ATTR_SIZES,
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&sizes);
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if(status == SEC_E_INSUFFICIENT_MEMORY)
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return CURLE_OUT_OF_MEMORY;
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if(status != SEC_E_OK)
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return CURLE_AUTH_ERROR;
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/* Setup the "input" security buffer */
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input_desc.ulVersion = SECBUFFER_VERSION;
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input_desc.cBuffers = 2;
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input_desc.pBuffers = input_buf;
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input_buf[0].BufferType = SECBUFFER_STREAM;
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input_buf[0].pvBuffer = (void *) Curl_bufref_ptr(chlg);
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input_buf[0].cbBuffer = curlx_uztoul(Curl_bufref_len(chlg));
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input_buf[1].BufferType = SECBUFFER_DATA;
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input_buf[1].pvBuffer = NULL;
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input_buf[1].cbBuffer = 0;
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/* Decrypt the inbound challenge and obtain the qop */
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status = s_pSecFn->DecryptMessage(krb5->context, &input_desc, 0, &qop);
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if(status != SEC_E_OK) {
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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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/* Not 4 octets long so fail as per RFC4752 Section 3.1 */
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if(input_buf[1].cbBuffer != 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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/* Extract the security layer and the maximum message size */
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indata = input_buf[1].pvBuffer;
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sec_layer = indata[0];
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max_size = ((unsigned long)indata[1] << 16) |
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((unsigned long)indata[2] << 8) | indata[3];
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/* Free the challenge as it is not required anymore */
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s_pSecFn->FreeContextBuffer(input_buf[1].pvBuffer);
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/* Process the security layer */
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if(!(sec_layer & KERB_WRAP_NO_ENCRYPT)) {
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infof(data, "GSSAPI handshake failure (invalid security layer)");
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return CURLE_BAD_CONTENT_ENCODING;
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}
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sec_layer &= KERB_WRAP_NO_ENCRYPT; /* We do not support a security layer */
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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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/* Allocate the trailer */
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trailer = malloc(sizes.cbSecurityTrailer);
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if(!trailer)
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return CURLE_OUT_OF_MEMORY;
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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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free(trailer);
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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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/* If given, append the authorization identity. */
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if(authzid && *authzid)
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memcpy(message + 4, authzid, messagelen - 4);
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/* Allocate the padding */
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padding = malloc(sizes.cbBlockSize);
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if(!padding) {
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free(message);
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free(trailer);
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return CURLE_OUT_OF_MEMORY;
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}
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/* Setup the "authentication data" security buffer */
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wrap_desc.ulVersion = SECBUFFER_VERSION;
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wrap_desc.cBuffers = 3;
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wrap_desc.pBuffers = wrap_buf;
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wrap_buf[0].BufferType = SECBUFFER_TOKEN;
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wrap_buf[0].pvBuffer = trailer;
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wrap_buf[0].cbBuffer = sizes.cbSecurityTrailer;
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wrap_buf[1].BufferType = SECBUFFER_DATA;
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wrap_buf[1].pvBuffer = message;
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wrap_buf[1].cbBuffer = curlx_uztoul(messagelen);
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wrap_buf[2].BufferType = SECBUFFER_PADDING;
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wrap_buf[2].pvBuffer = padding;
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wrap_buf[2].cbBuffer = sizes.cbBlockSize;
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/* Encrypt the data */
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status = s_pSecFn->EncryptMessage(krb5->context, KERB_WRAP_NO_ENCRYPT,
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&wrap_desc, 0);
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if(status != SEC_E_OK) {
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free(padding);
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free(message);
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free(trailer);
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if(status == SEC_E_INSUFFICIENT_MEMORY)
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return CURLE_OUT_OF_MEMORY;
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return CURLE_AUTH_ERROR;
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}
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/* Allocate the encryption (wrap) buffer */
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appdatalen = wrap_buf[0].cbBuffer + wrap_buf[1].cbBuffer +
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wrap_buf[2].cbBuffer;
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appdata = malloc(appdatalen);
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if(!appdata) {
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free(padding);
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free(message);
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free(trailer);
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return CURLE_OUT_OF_MEMORY;
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}
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/* Populate the encryption buffer */
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memcpy(appdata, wrap_buf[0].pvBuffer, wrap_buf[0].cbBuffer);
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offset += wrap_buf[0].cbBuffer;
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memcpy(appdata + offset, wrap_buf[1].pvBuffer, wrap_buf[1].cbBuffer);
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offset += wrap_buf[1].cbBuffer;
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memcpy(appdata + offset, wrap_buf[2].pvBuffer, wrap_buf[2].cbBuffer);
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/* Free all of our local buffers */
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free(padding);
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free(message);
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free(trailer);
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/* Return the response. */
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Curl_bufref_set(out, appdata, appdatalen, curl_free);
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return CURLE_OK;
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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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/* Free our security context */
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if(krb5->context) {
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s_pSecFn->DeleteSecurityContext(krb5->context);
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free(krb5->context);
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krb5->context = NULL;
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}
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/* Free our credentials handle */
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if(krb5->credentials) {
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s_pSecFn->FreeCredentialsHandle(krb5->credentials);
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free(krb5->credentials);
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krb5->credentials = NULL;
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}
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/* Free our identity */
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Curl_sspi_free_identity(krb5->p_identity);
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krb5->p_identity = NULL;
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/* Free the SPN and output token */
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Curl_safefree(krb5->spn);
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Curl_safefree(krb5->output_token);
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/* Reset any variables */
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krb5->token_max = 0;
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}
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#endif /* USE_WINDOWS_SSPI && USE_KERBEROS5 */
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