433 lines
14 KiB
C
433 lines
14 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Implementation
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* RPC Secure Context Binding
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*
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* Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <winpr/crt.h>
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#include <assert.h>
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#include <freerdp/log.h>
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#include "rpc_client.h"
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#include "rts.h"
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#include "rpc_bind.h"
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#define TAG FREERDP_TAG("core.gateway.rpc")
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/**
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* Connection-Oriented RPC Protocol Client Details:
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* http://msdn.microsoft.com/en-us/library/cc243724/
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*/
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/* Syntax UUIDs */
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const p_uuid_t TSGU_UUID = {
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0x44E265DD, /* time_low */
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0x7DAF, /* time_mid */
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0x42CD, /* time_hi_and_version */
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0x85, /* clock_seq_hi_and_reserved */
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0x60, /* clock_seq_low */
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{ 0x3C, 0xDB, 0x6E, 0x7A, 0x27, 0x29 } /* node[6] */
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};
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const p_uuid_t NDR_UUID = {
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0x8A885D04, /* time_low */
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0x1CEB, /* time_mid */
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0x11C9, /* time_hi_and_version */
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0x9F, /* clock_seq_hi_and_reserved */
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0xE8, /* clock_seq_low */
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{ 0x08, 0x00, 0x2B, 0x10, 0x48, 0x60 } /* node[6] */
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};
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const p_uuid_t BTFN_UUID = {
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0x6CB71C2C, /* time_low */
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0x9812, /* time_mid */
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0x4540, /* time_hi_and_version */
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0x03, /* clock_seq_hi_and_reserved */
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0x00, /* clock_seq_low */
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } /* node[6] */
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};
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/**
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* Secure Connection-Oriented RPC Packet Sequence
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*
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* Client Server
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* | |
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* |-------------------SECURE_BIND-------------------->|
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* | |
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* |<----------------SECURE_BIND_ACK-------------------|
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* | |
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* |--------------------RPC_AUTH_3-------------------->|
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* | |
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* | |
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* |------------------REQUEST_PDU_#1------------------>|
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* |------------------REQUEST_PDU_#2------------------>|
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* | |
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* | ... |
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* | |
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* |<-----------------RESPONSE_PDU_#1------------------|
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* |<-----------------RESPONSE_PDU_#2------------------|
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* | |
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* | ... |
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*/
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/**
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* SECURE_BIND: RPC bind PDU with sec_trailer and auth_token. Auth_token is generated by calling
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* the implementation equivalent of the abstract GSS_Init_sec_context call. Upon receiving that, the
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* server calls the implementation equivalent of the abstract GSS_Accept_sec_context call, which
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* returns an auth_token and continue status in this example. Assume the following:
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*
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* 1) The client chooses the auth_context_id field in the sec_trailer sent with this PDU to be 1.
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*
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* 2) The client uses the RPC_C_AUTHN_LEVEL_PKT_PRIVACY authentication level and the
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* Authentication Service (AS) NTLM.
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*
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* 3) The client sets the PFC_SUPPORT_HEADER_SIGN flag in the PDU header.
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*/
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int rpc_send_bind_pdu(rdpRpc* rpc)
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{
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BOOL continueNeeded = FALSE;
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int status = -1;
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wStream* buffer = NULL;
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UINT32 offset;
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RpcClientCall* clientCall;
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p_cont_elem_t* p_cont_elem;
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rpcconn_bind_hdr_t bind_pdu = { 0 };
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BOOL promptPassword = FALSE;
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rdpSettings* settings;
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freerdp* instance;
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RpcVirtualConnection* connection;
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RpcInChannel* inChannel;
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const SecBuffer* sbuffer = NULL;
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assert(rpc);
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settings = rpc->settings;
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assert(settings);
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instance = (freerdp*)settings->instance;
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assert(instance);
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connection = rpc->VirtualConnection;
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assert(connection);
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inChannel = connection->DefaultInChannel;
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WLog_DBG(TAG, "Sending Bind PDU");
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ntlm_free(rpc->ntlm);
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rpc->ntlm = ntlm_new();
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if (!rpc->ntlm)
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goto fail;
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if ((!settings->GatewayPassword) || (!settings->GatewayUsername) ||
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(!strlen(settings->GatewayPassword)) || (!strlen(settings->GatewayUsername)))
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{
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promptPassword = TRUE;
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}
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if (promptPassword)
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{
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if (freerdp_shall_disconnect(instance))
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return -1;
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if (!instance->GatewayAuthenticate)
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{
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freerdp_set_last_error_log(instance->context,
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FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
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return 0;
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}
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else
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{
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BOOL proceed =
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instance->GatewayAuthenticate(instance, &settings->GatewayUsername,
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&settings->GatewayPassword, &settings->GatewayDomain);
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if (!proceed)
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{
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freerdp_set_last_error_log(instance->context,
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FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
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return 0;
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}
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if (settings->GatewayUseSameCredentials)
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{
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settings->Username = _strdup(settings->GatewayUsername);
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settings->Domain = _strdup(settings->GatewayDomain);
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settings->Password = _strdup(settings->GatewayPassword);
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if (!settings->Username || !settings->Domain || settings->Password)
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goto fail;
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}
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}
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}
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if (!ntlm_client_init(rpc->ntlm, FALSE, settings->GatewayUsername, settings->GatewayDomain,
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settings->GatewayPassword, NULL))
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goto fail;
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if (!ntlm_client_make_spn(rpc->ntlm, NULL, settings->GatewayHostname))
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goto fail;
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if (!ntlm_authenticate(rpc->ntlm, &continueNeeded))
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goto fail;
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if (!continueNeeded)
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goto fail;
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sbuffer = ntlm_client_get_output_buffer(rpc->ntlm);
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if (!sbuffer)
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goto fail;
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bind_pdu.header = rpc_pdu_header_init(rpc);
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bind_pdu.header.auth_length = (UINT16)sbuffer->cbBuffer;
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bind_pdu.auth_verifier.auth_value = sbuffer->pvBuffer;
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bind_pdu.header.ptype = PTYPE_BIND;
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bind_pdu.header.pfc_flags =
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PFC_FIRST_FRAG | PFC_LAST_FRAG | PFC_SUPPORT_HEADER_SIGN | PFC_CONC_MPX;
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bind_pdu.header.call_id = 2;
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bind_pdu.max_xmit_frag = rpc->max_xmit_frag;
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bind_pdu.max_recv_frag = rpc->max_recv_frag;
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bind_pdu.assoc_group_id = 0;
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bind_pdu.p_context_elem.n_context_elem = 2;
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bind_pdu.p_context_elem.reserved = 0;
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bind_pdu.p_context_elem.reserved2 = 0;
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bind_pdu.p_context_elem.p_cont_elem =
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calloc(bind_pdu.p_context_elem.n_context_elem, sizeof(p_cont_elem_t));
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if (!bind_pdu.p_context_elem.p_cont_elem)
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goto fail;
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p_cont_elem = &bind_pdu.p_context_elem.p_cont_elem[0];
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p_cont_elem->p_cont_id = 0;
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p_cont_elem->n_transfer_syn = 1;
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p_cont_elem->reserved = 0;
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CopyMemory(&(p_cont_elem->abstract_syntax.if_uuid), &TSGU_UUID, sizeof(p_uuid_t));
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p_cont_elem->abstract_syntax.if_version = TSGU_SYNTAX_IF_VERSION;
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p_cont_elem->transfer_syntaxes = malloc(sizeof(p_syntax_id_t));
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if (!p_cont_elem->transfer_syntaxes)
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goto fail;
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CopyMemory(&(p_cont_elem->transfer_syntaxes[0].if_uuid), &NDR_UUID, sizeof(p_uuid_t));
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p_cont_elem->transfer_syntaxes[0].if_version = NDR_SYNTAX_IF_VERSION;
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p_cont_elem = &bind_pdu.p_context_elem.p_cont_elem[1];
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p_cont_elem->p_cont_id = 1;
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p_cont_elem->n_transfer_syn = 1;
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p_cont_elem->reserved = 0;
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CopyMemory(&(p_cont_elem->abstract_syntax.if_uuid), &TSGU_UUID, sizeof(p_uuid_t));
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p_cont_elem->abstract_syntax.if_version = TSGU_SYNTAX_IF_VERSION;
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p_cont_elem->transfer_syntaxes = malloc(sizeof(p_syntax_id_t));
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if (!p_cont_elem->transfer_syntaxes)
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goto fail;
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CopyMemory(&(p_cont_elem->transfer_syntaxes[0].if_uuid), &BTFN_UUID, sizeof(p_uuid_t));
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p_cont_elem->transfer_syntaxes[0].if_version = BTFN_SYNTAX_IF_VERSION;
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offset = 116;
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bind_pdu.auth_verifier.auth_type = RPC_C_AUTHN_WINNT;
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bind_pdu.auth_verifier.auth_level = RPC_C_AUTHN_LEVEL_PKT_INTEGRITY;
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bind_pdu.auth_verifier.auth_reserved = 0x00;
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bind_pdu.auth_verifier.auth_context_id = 0x00000000;
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offset += (8 + bind_pdu.header.auth_length);
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bind_pdu.header.frag_length = offset;
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buffer = Stream_New(NULL, bind_pdu.header.frag_length);
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if (!buffer)
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goto fail;
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if (!rts_write_pdu_bind(buffer, &bind_pdu))
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goto fail;
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clientCall = rpc_client_call_new(bind_pdu.header.call_id, 0);
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if (!clientCall)
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goto fail;
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if (ArrayList_Add(rpc->client->ClientCallList, clientCall) < 0)
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{
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rpc_client_call_free(clientCall);
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goto fail;
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}
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Stream_SealLength(buffer);
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status = rpc_in_channel_send_pdu(inChannel, Stream_Buffer(buffer), Stream_Length(buffer));
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fail:
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if (bind_pdu.p_context_elem.p_cont_elem)
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{
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free(bind_pdu.p_context_elem.p_cont_elem[0].transfer_syntaxes);
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free(bind_pdu.p_context_elem.p_cont_elem[1].transfer_syntaxes);
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}
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free(bind_pdu.p_context_elem.p_cont_elem);
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Stream_Free(buffer, TRUE);
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return (status > 0) ? 1 : -1;
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}
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/**
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* Maximum Transmit/Receive Fragment Size Negotiation
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*
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* The client determines, and then sends in the bind PDU, its desired maximum size for transmitting
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* fragments, and its desired maximum receive fragment size. Similarly, the server determines its
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* desired maximum sizes for transmitting and receiving fragments. Transmit and receive sizes may be
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* different to help preserve buffering. When the server receives the client’s values, it sets its
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* operational transmit size to the minimum of the client’s receive size (from the bind PDU) and its
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* own desired transmit size. Then it sets its actual receive size to the minimum of the client’s
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* transmit size (from the bind) and its own desired receive size. The server then returns its
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* operational values in the bind_ack PDU. The client then sets its operational values from the
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* received bind_ack PDU. The received transmit size becomes the client’s receive size, and the
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* received receive size becomes the client’s transmit size. Either party may use receive buffers
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* larger than negotiated — although this will not provide any advantage — but may not transmit
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* larger fragments than negotiated.
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*/
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/**
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*
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* SECURE_BIND_ACK: RPC bind_ack PDU with sec_trailer and auth_token. The PFC_SUPPORT_HEADER_SIGN
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* flag in the PDU header is also set in this example. Auth_token is generated by the server in the
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* previous step. Upon receiving that PDU, the client calls the implementation equivalent of the
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* abstract GSS_Init_sec_context call, which returns an auth_token and continue status in this
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* example.
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*/
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BOOL rpc_recv_bind_ack_pdu(rdpRpc* rpc, wStream* s)
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{
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BOOL rc = FALSE;
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BOOL continueNeeded = FALSE;
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const BYTE* auth_data;
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size_t pos, end;
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rpcconn_hdr_t header = { 0 };
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assert(rpc);
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assert(rpc->ntlm);
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assert(s);
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pos = Stream_GetPosition(s);
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if (!rts_read_pdu_header(s, &header))
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goto fail;
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WLog_DBG(TAG, "Receiving BindAck PDU");
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rpc->max_recv_frag = header.bind_ack.max_xmit_frag;
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rpc->max_xmit_frag = header.bind_ack.max_recv_frag;
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/* Get the correct offset in the input data and pass that on as input buffer.
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* rts_read_pdu_header did already do consistency checks */
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end = Stream_GetPosition(s);
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Stream_SetPosition(s, pos + header.common.frag_length - header.common.auth_length);
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auth_data = Stream_Pointer(s);
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Stream_SetPosition(s, end);
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if (!ntlm_client_set_input_buffer(rpc->ntlm, TRUE, auth_data, header.common.auth_length))
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goto fail;
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if (!ntlm_authenticate(rpc->ntlm, &continueNeeded))
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goto fail;
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if (continueNeeded)
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goto fail;
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rc = TRUE;
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fail:
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rts_free_pdu_header(&header, FALSE);
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return rc;
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}
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/**
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* RPC_AUTH_3: The client knows that this is an NTLM that uses three legs. It sends an rpc_auth_3
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* PDU with the auth_token obtained in the previous step. Upon receiving this PDU, the server calls
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* the implementation equivalent of the abstract GSS_Accept_sec_context call, which returns success
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* status in this example.
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*/
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int rpc_send_rpc_auth_3_pdu(rdpRpc* rpc)
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{
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int status = -1;
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wStream* buffer;
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size_t offset;
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const SecBuffer* sbuffer;
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RpcClientCall* clientCall;
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rpcconn_rpc_auth_3_hdr_t auth_3_pdu = { 0 };
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RpcVirtualConnection* connection;
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RpcInChannel* inChannel;
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assert(rpc);
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connection = rpc->VirtualConnection;
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assert(connection);
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inChannel = connection->DefaultInChannel;
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assert(inChannel);
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WLog_DBG(TAG, "Sending RpcAuth3 PDU");
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sbuffer = ntlm_client_get_output_buffer(rpc->ntlm);
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if (!sbuffer)
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return -1;
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auth_3_pdu.header = rpc_pdu_header_init(rpc);
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auth_3_pdu.header.auth_length = (UINT16)sbuffer->cbBuffer;
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auth_3_pdu.auth_verifier.auth_value = sbuffer->pvBuffer;
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auth_3_pdu.header.ptype = PTYPE_RPC_AUTH_3;
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auth_3_pdu.header.pfc_flags = PFC_FIRST_FRAG | PFC_LAST_FRAG | PFC_CONC_MPX;
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auth_3_pdu.header.call_id = 2;
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auth_3_pdu.max_xmit_frag = rpc->max_xmit_frag;
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auth_3_pdu.max_recv_frag = rpc->max_recv_frag;
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offset = 20;
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auth_3_pdu.auth_verifier.auth_pad_length = rpc_offset_align(&offset, 4);
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auth_3_pdu.auth_verifier.auth_type = RPC_C_AUTHN_WINNT;
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auth_3_pdu.auth_verifier.auth_level = RPC_C_AUTHN_LEVEL_PKT_INTEGRITY;
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auth_3_pdu.auth_verifier.auth_reserved = 0x00;
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auth_3_pdu.auth_verifier.auth_context_id = 0x00000000;
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offset += (8 + auth_3_pdu.header.auth_length);
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auth_3_pdu.header.frag_length = offset;
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buffer = Stream_New(NULL, auth_3_pdu.header.frag_length);
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if (!buffer)
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return -1;
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if (!rts_write_pdu_auth3(buffer, &auth_3_pdu))
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goto fail;
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clientCall = rpc_client_call_new(auth_3_pdu.header.call_id, 0);
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if (ArrayList_Add(rpc->client->ClientCallList, clientCall) >= 0)
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{
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Stream_SealLength(buffer);
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status = rpc_in_channel_send_pdu(inChannel, Stream_Buffer(buffer), Stream_Length(buffer));
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}
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fail:
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Stream_Free(buffer, TRUE);
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return (status > 0) ? 1 : -1;
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}
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