325 lines
10 KiB
C
325 lines
10 KiB
C
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/***************************************************************************
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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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* Copyright (C) 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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* 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(HAVE_GSSAPI) && defined(USE_KERBEROS5)
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#include <curl/curl.h>
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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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/* 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 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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* 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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(void) userp;
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(void) passwdp;
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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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/* 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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/* 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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free(spn);
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return CURLE_AUTH_ERROR;
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}
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free(spn);
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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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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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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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Curl_gss_log_error(data, "gss_init_sec_context() failed: ",
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major_status, minor_status);
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return CURLE_AUTH_ERROR;
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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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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] - 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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/* 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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/* 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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/* 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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/* 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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/* 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 = ((unsigned int)indata[1] << 16) |
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((unsigned int)indata[2] << 8) | indata[3];
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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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/* 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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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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/* 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 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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/* 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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/* 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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/* 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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/* 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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/* Free the message buffer */
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free(message);
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return result;
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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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/* 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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/* 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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#endif /* HAVE_GSSAPI && USE_KERBEROS5 */
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