Program: CWE-125
Project: CVE-2020-11089
Buggy source:
/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Remote Desktop Gateway (RDG)
 *
 * Copyright 2015 Denis Vincent <dvincent@devolutions.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <assert.h>

#include <winpr/crt.h>
#include <winpr/synch.h>
#include <winpr/print.h>
#include <winpr/stream.h>
#include <winpr/winsock.h>

#include <freerdp/log.h>
#include <freerdp/error.h>
#include <freerdp/utils/ringbuffer.h>

#include "rdg.h"
#include "../proxy.h"
#include "../rdp.h"
#include "../../crypto/opensslcompat.h"
#include "rpc_fault.h"

#define TAG FREERDP_TAG("core.gateway.rdg")

/* HTTP channel response fields present flags. */
#define HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID 0x1
#define HTTP_CHANNEL_RESPONSE_OPTIONAL 0x2
#define HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT 0x4

/* HTTP extended auth. */
#define HTTP_EXTENDED_AUTH_NONE 0x0
#define HTTP_EXTENDED_AUTH_SC 0x1         /* Smart card authentication. */
#define HTTP_EXTENDED_AUTH_PAA 0x02       /* Pluggable authentication. */
#define HTTP_EXTENDED_AUTH_SSPI_NTLM 0x04 /* NTLM extended authentication. */

/* HTTP packet types. */
#define PKT_TYPE_HANDSHAKE_REQUEST 0x1
#define PKT_TYPE_HANDSHAKE_RESPONSE 0x2
#define PKT_TYPE_EXTENDED_AUTH_MSG 0x3
#define PKT_TYPE_TUNNEL_CREATE 0x4
#define PKT_TYPE_TUNNEL_RESPONSE 0x5
#define PKT_TYPE_TUNNEL_AUTH 0x6
#define PKT_TYPE_TUNNEL_AUTH_RESPONSE 0x7
#define PKT_TYPE_CHANNEL_CREATE 0x8
#define PKT_TYPE_CHANNEL_RESPONSE 0x9
#define PKT_TYPE_DATA 0xA
#define PKT_TYPE_SERVICE_MESSAGE 0xB
#define PKT_TYPE_REAUTH_MESSAGE 0xC
#define PKT_TYPE_KEEPALIVE 0xD
#define PKT_TYPE_CLOSE_CHANNEL 0x10
#define PKT_TYPE_CLOSE_CHANNEL_RESPONSE 0x11

/* HTTP tunnel auth fields present flags. */
#define HTTP_TUNNEL_AUTH_FIELD_SOH 0x1

/* HTTP tunnel auth response fields present flags. */
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS 0x1
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT 0x2
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE 0x4

/* HTTP tunnel packet fields present flags. */
#define HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE 0x1
#define HTTP_TUNNEL_PACKET_FIELD_REAUTH 0x2

/* HTTP tunnel redir flags. */
#define HTTP_TUNNEL_REDIR_ENABLE_ALL 0x80000000
#define HTTP_TUNNEL_REDIR_DISABLE_ALL 0x40000000
#define HTTP_TUNNEL_REDIR_DISABLE_DRIVE 0x1
#define HTTP_TUNNEL_REDIR_DISABLE_PRINTER 0x2
#define HTTP_TUNNEL_REDIR_DISABLE_PORT 0x4
#define HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD 0x8
#define HTTP_TUNNEL_REDIR_DISABLE_PNP 0x10

/* HTTP tunnel response fields present flags. */
#define HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID 0x1
#define HTTP_TUNNEL_RESPONSE_FIELD_CAPS 0x2
#define HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ 0x4
#define HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG 0x10

/* HTTP capability type enumeration. */
#define HTTP_CAPABILITY_TYPE_QUAR_SOH 0x1
#define HTTP_CAPABILITY_IDLE_TIMEOUT 0x2
#define HTTP_CAPABILITY_MESSAGING_CONSENT_SIGN 0x4
#define HTTP_CAPABILITY_MESSAGING_SERVICE_MSG 0x8
#define HTTP_CAPABILITY_REAUTH 0x10
#define HTTP_CAPABILITY_UDP_TRANSPORT 0x20

struct rdp_rdg
{
	rdpContext* context;
	rdpSettings* settings;
	BOOL attached;
	BIO* frontBio;
	rdpTls* tlsIn;
	rdpTls* tlsOut;
	rdpNtlm* ntlm;
	HttpContext* http;
	CRITICAL_SECTION writeSection;

	UUID guid;

	int state;
	UINT16 packetRemainingCount;
	UINT16 reserved1;
	int timeout;
	UINT16 extAuth;
	UINT16 reserved2;
};

enum
{
	RDG_CLIENT_STATE_INITIAL,
	RDG_CLIENT_STATE_HANDSHAKE,
	RDG_CLIENT_STATE_TUNNEL_CREATE,
	RDG_CLIENT_STATE_TUNNEL_AUTHORIZE,
	RDG_CLIENT_STATE_CHANNEL_CREATE,
	RDG_CLIENT_STATE_OPENED,
};

#pragma pack(push, 1)

typedef struct rdg_packet_header
{
	UINT16 type;
	UINT16 reserved;
	UINT32 packetLength;
} RdgPacketHeader;

#pragma pack(pop)

typedef struct
{
	UINT32 code;
	const char* name;
} t_err_mapping;

static const t_err_mapping tunnel_response_fields_present[] = {
	{ HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID, "HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_CAPS, "HTTP_TUNNEL_RESPONSE_FIELD_CAPS" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ, "HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG, "HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG" }
};

static const t_err_mapping channel_response_fields_present[] = {
	{ HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID, "HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID" },
	{ HTTP_CHANNEL_RESPONSE_OPTIONAL, "HTTP_CHANNEL_RESPONSE_OPTIONAL" },
	{ HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT, "HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT" }
};

static const t_err_mapping tunnel_authorization_response_fields_present[] = {
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS, "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS" },
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT,
	  "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT" },
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE,
	  "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE" }
};

static const t_err_mapping extended_auth[] = {
	{ HTTP_EXTENDED_AUTH_NONE, "HTTP_EXTENDED_AUTH_NONE" },
	{ HTTP_EXTENDED_AUTH_SC, "HTTP_EXTENDED_AUTH_SC" },
	{ HTTP_EXTENDED_AUTH_PAA, "HTTP_EXTENDED_AUTH_PAA" },
	{ HTTP_EXTENDED_AUTH_SSPI_NTLM, "HTTP_EXTENDED_AUTH_SSPI_NTLM" }
};

static const char* fields_present_to_string(UINT16 fieldsPresent, const t_err_mapping* map,
                                            size_t elements)
{
	size_t x = 0;
	static char buffer[1024] = { 0 };
	char fields[12];
	memset(buffer, 0, sizeof(buffer));

	for (x = 0; x < elements; x++)
	{
		if (buffer[0] != '\0')
			strcat(buffer, "|");

		if ((map[x].code & fieldsPresent) != 0)
			strcat(buffer, map[x].name);
	}

	sprintf_s(fields, ARRAYSIZE(fields), " [%04" PRIx16 "]", fieldsPresent);
	strcat(buffer, fields);
	return buffer;
}

static const char* channel_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, channel_response_fields_present,
	                                ARRAYSIZE(channel_response_fields_present));
}

static const char* tunnel_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, tunnel_response_fields_present,
	                                ARRAYSIZE(tunnel_response_fields_present));
}

static const char* tunnel_authorization_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, tunnel_authorization_response_fields_present,
	                                ARRAYSIZE(tunnel_authorization_response_fields_present));
}

static const char* extended_auth_to_string(UINT16 auth)
{
	if (auth == HTTP_EXTENDED_AUTH_NONE)
		return "HTTP_EXTENDED_AUTH_NONE [0x0000]";

	return fields_present_to_string(auth, extended_auth, ARRAYSIZE(extended_auth));
}

static BOOL rdg_write_packet(rdpRdg* rdg, wStream* sPacket)
{
	size_t s;
	int status;
	wStream* sChunk;
	char chunkSize[11];
	sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIXz "\r\n", Stream_Length(sPacket));
	sChunk = Stream_New(NULL, strnlen(chunkSize, sizeof(chunkSize)) + Stream_Length(sPacket) + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, strnlen(chunkSize, sizeof(chunkSize)));
	Stream_Write(sChunk, Stream_Buffer(sPacket), Stream_Length(sPacket));
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s > INT_MAX)
		return FALSE;

	status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);
	Stream_Free(sChunk, TRUE);

	if (status < 0)
		return FALSE;

	return TRUE;
}

static BOOL rdg_read_all(rdpTls* tls, BYTE* buffer, int size)
{
	int status;
	int readCount = 0;
	BYTE* pBuffer = buffer;

	while (readCount < size)
	{
		status = BIO_read(tls->bio, pBuffer, size - readCount);

		if (status <= 0)
		{
			if (!BIO_should_retry(tls->bio))
				return FALSE;

			continue;
		}

		readCount += status;
		pBuffer += status;
	}

	return TRUE;
}

static wStream* rdg_receive_packet(rdpRdg* rdg)
{
	wStream* s;
	const size_t header = sizeof(RdgPacketHeader);
	size_t packetLength;
	assert(header <= INT_MAX);
	s = Stream_New(NULL, 1024);

	if (!s)
		return NULL;

	if (!rdg_read_all(rdg->tlsOut, Stream_Buffer(s), header))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	Stream_Seek(s, 4);
	Stream_Read_UINT32(s, packetLength);

	if ((packetLength > INT_MAX) || !Stream_EnsureCapacity(s, packetLength))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	if (!rdg_read_all(rdg->tlsOut, Stream_Buffer(s) + header, (int)packetLength - (int)header))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	Stream_SetLength(s, packetLength);
	return s;
}

static BOOL rdg_send_handshake(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	s = Stream_New(NULL, 14);

	if (!s)
		return FALSE;

	Stream_Write_UINT16(s, PKT_TYPE_HANDSHAKE_REQUEST); /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                          /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, 14);                         /* PacketLength (4 bytes) */
	Stream_Write_UINT8(s, 1);                           /* VersionMajor (1 byte) */
	Stream_Write_UINT8(s, 0);                           /* VersionMinor (1 byte) */
	Stream_Write_UINT16(s, 0);                          /* ClientVersion (2 bytes), must be 0 */
	Stream_Write_UINT16(s, rdg->extAuth);               /* ExtendedAuthentication (2 bytes) */
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_HANDSHAKE;
	}

	return status;
}

static BOOL rdg_send_tunnel_request(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	UINT32 packetSize = 16;
	UINT16 fieldsPresent = 0;
	WCHAR* PAACookie = NULL;
	int PAACookieLen = 0;

	if (rdg->extAuth == HTTP_EXTENDED_AUTH_PAA)
	{
		PAACookieLen =
		    ConvertToUnicode(CP_UTF8, 0, rdg->settings->GatewayAccessToken, -1, &PAACookie, 0);

		if (!PAACookie || (PAACookieLen < 0) || (PAACookieLen > UINT16_MAX / 2))
		{
			free(PAACookie);
			return FALSE;
		}

		packetSize += 2 + (UINT32)PAACookieLen * sizeof(WCHAR);
		fieldsPresent = HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE;
	}

	s = Stream_New(NULL, packetSize);

	if (!s)
	{
		free(PAACookie);
		return FALSE;
	}

	Stream_Write_UINT16(s, PKT_TYPE_TUNNEL_CREATE);        /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                             /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);                    /* PacketLength (4 bytes) */
	Stream_Write_UINT32(s, HTTP_CAPABILITY_TYPE_QUAR_SOH); /* CapabilityFlags (4 bytes) */
	Stream_Write_UINT16(s, fieldsPresent);                 /* FieldsPresent (2 bytes) */
	Stream_Write_UINT16(s, 0);                             /* Reserved (2 bytes), must be 0 */

	if (PAACookie)
	{
		Stream_Write_UINT16(s, (UINT16)PAACookieLen * 2); /* PAA cookie string length */
		Stream_Write_UTF16_String(s, PAACookie, (size_t)PAACookieLen);
	}

	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);
	free(PAACookie);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_TUNNEL_CREATE;
	}

	return status;
}

static BOOL rdg_send_tunnel_authorization(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	WCHAR* clientName = NULL;
	UINT32 packetSize;
	int clientNameLen =
	    ConvertToUnicode(CP_UTF8, 0, rdg->settings->ClientHostname, -1, &clientName, 0);

	if (!clientName || (clientNameLen < 0) || (clientNameLen > UINT16_MAX / 2))
	{
		free(clientName);
		return FALSE;
	}

	packetSize = 12 + (UINT32)clientNameLen * sizeof(WCHAR);
	s = Stream_New(NULL, packetSize);

	if (!s)
	{
		free(clientName);
		return FALSE;
	}

	Stream_Write_UINT16(s, PKT_TYPE_TUNNEL_AUTH);      /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                         /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);                /* PacketLength (4 bytes) */
	Stream_Write_UINT16(s, 0);                         /* FieldsPresent (2 bytes) */
	Stream_Write_UINT16(s, (UINT16)clientNameLen * 2); /* Client name string length */
	Stream_Write_UTF16_String(s, clientName, (size_t)clientNameLen);
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);
	free(clientName);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_TUNNEL_AUTHORIZE;
	}

	return status;
}

static BOOL rdg_send_channel_create(rdpRdg* rdg)
{
	wStream* s = NULL;
	BOOL status = FALSE;
	WCHAR* serverName = NULL;
	int serverNameLen =
	    ConvertToUnicode(CP_UTF8, 0, rdg->settings->ServerHostname, -1, &serverName, 0);
	UINT32 packetSize = 16 + ((UINT32)serverNameLen) * 2;

	if ((serverNameLen < 0) || (serverNameLen > UINT16_MAX / 2))
		goto fail;

	s = Stream_New(NULL, packetSize);

	if (!s)
		goto fail;

	Stream_Write_UINT16(s, PKT_TYPE_CHANNEL_CREATE); /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                       /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);              /* PacketLength (4 bytes) */
	Stream_Write_UINT8(s, 1);                        /* Number of resources. (1 byte) */
	Stream_Write_UINT8(s, 0);                        /* Number of alternative resources (1 byte) */
	Stream_Write_UINT16(s, (UINT16)rdg->settings->ServerPort); /* Resource port (2 bytes) */
	Stream_Write_UINT16(s, 3);                                 /* Protocol number (2 bytes) */
	Stream_Write_UINT16(s, (UINT16)serverNameLen * 2);
	Stream_Write_UTF16_String(s, serverName, (size_t)serverNameLen);
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
fail:
	free(serverName);
	Stream_Free(s, TRUE);

	if (status)
		rdg->state = RDG_CLIENT_STATE_CHANNEL_CREATE;

	return status;
}

static BOOL rdg_set_ntlm_auth_header(rdpNtlm* ntlm, HttpRequest* request)
{
	const SecBuffer* ntlmToken = ntlm_client_get_output_buffer(ntlm);
	char* base64NtlmToken = NULL;

	if (ntlmToken)
	{
		if (ntlmToken->cbBuffer > INT_MAX)
			return FALSE;

		base64NtlmToken = crypto_base64_encode(ntlmToken->pvBuffer, (int)ntlmToken->cbBuffer);
	}

	if (base64NtlmToken)
	{
		BOOL rc = http_request_set_auth_scheme(request, "NTLM") &&
		          http_request_set_auth_param(request, base64NtlmToken);
		free(base64NtlmToken);

		if (!rc)
			return FALSE;
	}

	return TRUE;
}

static wStream* rdg_build_http_request(rdpRdg* rdg, const char* method,
                                       const char* transferEncoding)
{
	wStream* s = NULL;
	HttpRequest* request = NULL;
	const char* uri;

	if (!rdg || !method)
		return NULL;

	uri = http_context_get_uri(rdg->http);
	request = http_request_new();

	if (!request)
		return NULL;

	if (!http_request_set_method(request, method) || !http_request_set_uri(request, uri))
		goto out;

	if (rdg->ntlm)
	{
		if (!rdg_set_ntlm_auth_header(rdg->ntlm, request))
			goto out;
	}

	if (transferEncoding)
	{
		http_request_set_transfer_encoding(request, transferEncoding);
	}

	s = http_request_write(rdg->http, request);
out:
	http_request_free(request);

	if (s)
		Stream_SealLength(s);

	return s;
}

static BOOL rdg_handle_ntlm_challenge(rdpNtlm* ntlm, HttpResponse* response)
{
	BOOL continueNeeded = FALSE;
	size_t len;
	const char* token64 = NULL;
	int ntlmTokenLength = 0;
	BYTE* ntlmTokenData = NULL;
	long StatusCode;

	if (!ntlm || !response)
		return FALSE;

	StatusCode = http_response_get_status_code(response);

	if (StatusCode != HTTP_STATUS_DENIED)
	{
		WLog_DBG(TAG, "Unexpected NTLM challenge HTTP status: %ld", StatusCode);
		return FALSE;
	}

	token64 = http_response_get_auth_token(response, "NTLM");

	if (!token64)
		return FALSE;

	len = strlen(token64);

	if (len > INT_MAX)
		return FALSE;

	crypto_base64_decode(token64, (int)len, &ntlmTokenData, &ntlmTokenLength);

	if (ntlmTokenLength < 0)
	{
		free(ntlmTokenData);
		return FALSE;
	}

	if (ntlmTokenData && ntlmTokenLength)
	{
		if (!ntlm_client_set_input_buffer(ntlm, FALSE, ntlmTokenData, (size_t)ntlmTokenLength))
			return FALSE;
	}

	if (!ntlm_authenticate(ntlm, &continueNeeded))
		return FALSE;

	if (continueNeeded)
		return FALSE;

	return TRUE;
}

static BOOL rdg_skip_seed_payload(rdpTls* tls, SSIZE_T lastResponseLength)
{
	BYTE seed_payload[10];
	const size_t size = sizeof(seed_payload);

	assert(size < SSIZE_MAX);

	/* Per [MS-TSGU] 3.3.5.1 step 4, after final OK response RDG server sends
	 * random "seed" payload of limited size. In practice it's 10 bytes.
	 */
	if (lastResponseLength < (SSIZE_T)size)
	{
		if (!rdg_read_all(tls, seed_payload, size - lastResponseLength))
		{
			return FALSE;
		}
	}

	return TRUE;
}

static BOOL rdg_process_handshake_response(rdpRdg* rdg, wStream* s)
{
	UINT32 errorCode;
	UINT16 serverVersion, extendedAuth;
	BYTE verMajor, verMinor;
	const char* error;
	WLog_DBG(TAG, "Handshake response received");

	if (rdg->state != RDG_CLIENT_STATE_HANDSHAKE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 10)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 10", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT8(s, verMajor);
	Stream_Read_UINT8(s, verMinor);
	Stream_Read_UINT16(s, serverVersion);
	Stream_Read_UINT16(s, extendedAuth);
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG,
	         "errorCode=%s, verMajor=%" PRId8 ", verMinor=%" PRId8 ", serverVersion=%" PRId16
	         ", extendedAuth=%s",
	         error, verMajor, verMinor, serverVersion, extended_auth_to_string(extendedAuth));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Handshake error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_tunnel_request(rdg);
}

static BOOL rdg_process_tunnel_response(rdpRdg* rdg, wStream* s)
{
	UINT16 serverVersion, fieldsPresent;
	UINT32 errorCode;
	const char* error;
	WLog_DBG(TAG, "Tunnel response received");

	if (rdg->state != RDG_CLIENT_STATE_TUNNEL_CREATE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 10)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 10", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT16(s, serverVersion);
	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "serverVersion=%" PRId16 ", errorCode=%s, fieldsPresent=%s", serverVersion, error,
	         tunnel_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Tunnel creation error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_tunnel_authorization(rdg);
}

static BOOL rdg_process_tunnel_authorization_response(rdpRdg* rdg, wStream* s)
{
	UINT32 errorCode;
	UINT16 fieldsPresent;
	const char* error;
	WLog_DBG(TAG, "Tunnel authorization received");

	if (rdg->state != RDG_CLIENT_STATE_TUNNEL_AUTHORIZE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "errorCode=%s, fieldsPresent=%s", error,
	         tunnel_authorization_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Tunnel authorization error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_channel_create(rdg);
}

static BOOL rdg_process_channel_response(rdpRdg* rdg, wStream* s)
{
	UINT16 fieldsPresent;
	UINT32 errorCode;
	const char* error;
	WLog_DBG(TAG, "Channel response received");

	if (rdg->state != RDG_CLIENT_STATE_CHANNEL_CREATE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "channel response errorCode=%s, fieldsPresent=%s", error,
	         channel_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "channel response errorCode=%s, fieldsPresent=%s", error,
		         channel_response_fields_present_to_string(fieldsPresent));
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	rdg->state = RDG_CLIENT_STATE_OPENED;
	return TRUE;
}

static BOOL rdg_process_packet(rdpRdg* rdg, wStream* s)
{
	BOOL status = TRUE;
	UINT16 type;
	UINT32 packetLength;
	Stream_SetPosition(s, 0);

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT16(s, type);
	Stream_Seek_UINT16(s); /* reserved */
	Stream_Read_UINT32(s, packetLength);

	if (Stream_Length(s) < packetLength)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected %" PRIuz, __FUNCTION__,
		         Stream_Length(s), packetLength);
		return FALSE;
	}

	switch (type)
	{
		case PKT_TYPE_HANDSHAKE_RESPONSE:
			status = rdg_process_handshake_response(rdg, s);
			break;

		case PKT_TYPE_TUNNEL_RESPONSE:
			status = rdg_process_tunnel_response(rdg, s);
			break;

		case PKT_TYPE_TUNNEL_AUTH_RESPONSE:
			status = rdg_process_tunnel_authorization_response(rdg, s);
			break;

		case PKT_TYPE_CHANNEL_RESPONSE:
			status = rdg_process_channel_response(rdg, s);
			break;

		case PKT_TYPE_DATA:
			WLog_ERR(TAG, "[%s] Unexpected packet type DATA", __FUNCTION__);
			return FALSE;
	}

	return status;
}

DWORD rdg_get_event_handles(rdpRdg* rdg, HANDLE* events, DWORD count)
{
	DWORD nCount = 0;
	assert(rdg != NULL);

	if (rdg->tlsOut && rdg->tlsOut->bio)
	{
		if (events && (nCount < count))
		{
			BIO_get_event(rdg->tlsOut->bio, &events[nCount]);
			nCount++;
		}
		else
			return 0;
	}

	if (rdg->tlsIn && rdg->tlsIn->bio)
	{
		if (events && (nCount < count))
		{
			BIO_get_event(rdg->tlsIn->bio, &events[nCount]);
			nCount++;
		}
		else
			return 0;
	}

	return nCount;
}

static BOOL rdg_get_gateway_credentials(rdpContext* context)
{
	rdpSettings* settings = context->settings;
	freerdp* instance = context->instance;

	if (!settings->GatewayPassword || !settings->GatewayUsername ||
	    !strlen(settings->GatewayPassword) || !strlen(settings->GatewayUsername))
	{
		if (freerdp_shall_disconnect(instance))
			return FALSE;

		if (!instance->GatewayAuthenticate)
		{
			freerdp_set_last_error_log(context, FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
			return FALSE;
		}
		else
		{
			BOOL proceed =
			    instance->GatewayAuthenticate(instance, &settings->GatewayUsername,
			                                  &settings->GatewayPassword, &settings->GatewayDomain);

			if (!proceed)
			{
				freerdp_set_last_error_log(context,
				                           FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
				return FALSE;
			}

			if (settings->GatewayUseSameCredentials)
			{
				if (settings->GatewayUsername)
				{
					free(settings->Username);

					if (!(settings->Username = _strdup(settings->GatewayUsername)))
						return FALSE;
				}

				if (settings->GatewayDomain)
				{
					free(settings->Domain);

					if (!(settings->Domain = _strdup(settings->GatewayDomain)))
						return FALSE;
				}

				if (settings->GatewayPassword)
				{
					free(settings->Password);

					if (!(settings->Password = _strdup(settings->GatewayPassword)))
						return FALSE;
				}
			}
		}
	}

	return TRUE;
}

static BOOL rdg_ntlm_init(rdpRdg* rdg, rdpTls* tls)
{
	BOOL continueNeeded = FALSE;
	rdpContext* context = rdg->context;
	rdpSettings* settings = context->settings;
	rdg->ntlm = ntlm_new();

	if (!rdg->ntlm)
		return FALSE;

	if (!rdg_get_gateway_credentials(context))
		return FALSE;

	if (!ntlm_client_init(rdg->ntlm, TRUE, settings->GatewayUsername, settings->GatewayDomain,
	                      settings->GatewayPassword, tls->Bindings))
		return FALSE;

	if (!ntlm_client_make_spn(rdg->ntlm, _T("HTTP"), settings->GatewayHostname))
		return FALSE;

	if (!ntlm_authenticate(rdg->ntlm, &continueNeeded))
		return FALSE;

	return continueNeeded;
}

static BOOL rdg_send_http_request(rdpRdg* rdg, rdpTls* tls, const char* method,
                                  const char* transferEncoding)
{
	size_t sz;
	wStream* s = NULL;
	int status = -1;
	s = rdg_build_http_request(rdg, method, transferEncoding);

	if (!s)
		return FALSE;

	sz = Stream_Length(s);

	if (sz <= INT_MAX)
		status = tls_write_all(tls, Stream_Buffer(s), (int)sz);

	Stream_Free(s, TRUE);
	return (status >= 0);
}

static BOOL rdg_tls_connect(rdpRdg* rdg, rdpTls* tls, const char* peerAddress, int timeout)
{
	int sockfd = 0;
	long status = 0;
	BIO* socketBio = NULL;
	BIO* bufferedBio = NULL;
	rdpSettings* settings = rdg->settings;
	const char* peerHostname = settings->GatewayHostname;
	UINT16 peerPort = (UINT16)settings->GatewayPort;
	const char *proxyUsername, *proxyPassword;
	BOOL isProxyConnection =
	    proxy_prepare(settings, &peerHostname, &peerPort, &proxyUsername, &proxyPassword);

	if (settings->GatewayPort > UINT16_MAX)
		return FALSE;

	sockfd = freerdp_tcp_connect(rdg->context, settings, peerAddress ? peerAddress : peerHostname,
	                             peerPort, timeout);

	if (sockfd < 0)
	{
		return FALSE;
	}

	socketBio = BIO_new(BIO_s_simple_socket());

	if (!socketBio)
	{
		closesocket((SOCKET)sockfd);
		return FALSE;
	}

	BIO_set_fd(socketBio, sockfd, BIO_CLOSE);
	bufferedBio = BIO_new(BIO_s_buffered_socket());

	if (!bufferedBio)
	{
		BIO_free_all(socketBio);
		return FALSE;
	}

	bufferedBio = BIO_push(bufferedBio, socketBio);
	status = BIO_set_nonblock(bufferedBio, TRUE);

	if (isProxyConnection)
	{
		if (!proxy_connect(settings, bufferedBio, proxyUsername, proxyPassword,
		                   settings->GatewayHostname, (UINT16)settings->GatewayPort))
		{
			BIO_free_all(bufferedBio);
			return FALSE;
		}
	}

	if (!status)
	{
		BIO_free_all(bufferedBio);
		return FALSE;
	}

	tls->hostname = settings->GatewayHostname;
	tls->port = (int)settings->GatewayPort;
	tls->isGatewayTransport = TRUE;
	status = tls_connect(tls, bufferedBio);
	if (status < 1)
	{
		rdpContext* context = rdg->context;
		if (status < 0)
		{
			freerdp_set_last_error_if_not(context, FREERDP_ERROR_TLS_CONNECT_FAILED);
		}
		else
		{
			freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_CANCELLED);
		}

		return FALSE;
	}
	return (status >= 1);
}

static BOOL rdg_establish_data_connection(rdpRdg* rdg, rdpTls* tls, const char* method,
                                          const char* peerAddress, int timeout, BOOL* rpcFallback)
{
	HttpResponse* response = NULL;
	long statusCode;
	SSIZE_T bodyLength;
	long StatusCode;

	if (!rdg_tls_connect(rdg, tls, peerAddress, timeout))
		return FALSE;

	if (rdg->extAuth == HTTP_EXTENDED_AUTH_NONE)
	{
		if (!rdg_ntlm_init(rdg, tls))
			return FALSE;

		if (!rdg_send_http_request(rdg, tls, method, NULL))
			return FALSE;

		response = http_response_recv(tls, TRUE);

		if (!response)
			return FALSE;

		StatusCode = http_response_get_status_code(response);

		switch (StatusCode)
		{
			case HTTP_STATUS_NOT_FOUND:
			{
				WLog_INFO(TAG, "RD Gateway does not support HTTP transport.");

				if (rpcFallback)
					*rpcFallback = TRUE;

				http_response_free(response);
				return FALSE;
			}
			default:
				break;
		}

		if (!rdg_handle_ntlm_challenge(rdg->ntlm, response))
		{
			http_response_free(response);
			return FALSE;
		}

		http_response_free(response);
	}

	if (!rdg_send_http_request(rdg, tls, method, NULL))
		return FALSE;

	ntlm_free(rdg->ntlm);
	rdg->ntlm = NULL;
	response = http_response_recv(tls, TRUE);

	if (!response)
		return FALSE;

	statusCode = http_response_get_status_code(response);
	bodyLength = http_response_get_body_length(response);
	http_response_free(response);
	WLog_DBG(TAG, "%s authorization result: %d", method, statusCode);

	switch (statusCode)
	{
		case HTTP_STATUS_OK:
			break;
		case HTTP_STATUS_DENIED:
			freerdp_set_last_error_log(rdg->context, FREERDP_ERROR_CONNECT_ACCESS_DENIED);
			return FALSE;
		default:
			return FALSE;
	}

	if (strcmp(method, "RDG_OUT_DATA") == 0)
	{
		if (!rdg_skip_seed_payload(tls, bodyLength))
			return FALSE;
	}
	else
	{
		if (!rdg_send_http_request(rdg, tls, method, "chunked"))
			return FALSE;
	}

	return TRUE;
}

static BOOL rdg_tunnel_connect(rdpRdg* rdg)
{
	BOOL status;
	wStream* s;
	rdg_send_handshake(rdg);

	while (rdg->state < RDG_CLIENT_STATE_OPENED)
	{
		status = FALSE;
		s = rdg_receive_packet(rdg);

		if (s)
		{
			status = rdg_process_packet(rdg, s);
			Stream_Free(s, TRUE);
		}

		if (!status)
		{
			rdg->context->rdp->transport->layer = TRANSPORT_LAYER_CLOSED;
			return FALSE;
		}
	}

	return TRUE;
}

BOOL rdg_connect(rdpRdg* rdg, int timeout, BOOL* rpcFallback)
{
	BOOL status;
	SOCKET outConnSocket = 0;
	char* peerAddress = NULL;
	assert(rdg != NULL);
	status =
	    rdg_establish_data_connection(rdg, rdg->tlsOut, "RDG_OUT_DATA", NULL, timeout, rpcFallback);

	if (status)
	{
		/* Establish IN connection with the same peer/server as OUT connection,
		 * even when server hostname resolves to different IP addresses.
		 */
		BIO_get_socket(rdg->tlsOut->underlying, &outConnSocket);
		peerAddress = freerdp_tcp_get_peer_address(outConnSocket);
		status = rdg_establish_data_connection(rdg, rdg->tlsIn, "RDG_IN_DATA", peerAddress, timeout,
		                                       NULL);
		free(peerAddress);
	}

	if (!status)
	{
		rdg->context->rdp->transport->layer = TRANSPORT_LAYER_CLOSED;
		return FALSE;
	}

	status = rdg_tunnel_connect(rdg);

	if (!status)
		return FALSE;

	return TRUE;
}

static int rdg_write_data_packet(rdpRdg* rdg, const BYTE* buf, int isize)
{
	int status;
	size_t s;
	wStream* sChunk;
	size_t size = (size_t)isize;
	size_t packetSize = size + 10;
	char chunkSize[11];

	if ((isize < 0) || (isize > UINT16_MAX))
		return -1;

	if (size < 1)
		return 0;

	sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIxz "\r\n", packetSize);
	sChunk = Stream_New(NULL, strnlen(chunkSize, sizeof(chunkSize)) + packetSize + 2);

	if (!sChunk)
		return -1;

	Stream_Write(sChunk, chunkSize, strnlen(chunkSize, sizeof(chunkSize)));
	Stream_Write_UINT16(sChunk, PKT_TYPE_DATA);      /* Type */
	Stream_Write_UINT16(sChunk, 0);                  /* Reserved */
	Stream_Write_UINT32(sChunk, (UINT32)packetSize); /* Packet length */
	Stream_Write_UINT16(sChunk, (UINT16)size);       /* Data size */
	Stream_Write(sChunk, buf, size);                 /* Data */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s > INT_MAX)
		return -1;

	status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);
	Stream_Free(sChunk, TRUE);

	if (status < 0)
		return -1;

	return (int)size;
}

static BOOL rdg_process_close_packet(rdpRdg* rdg)
{
	int status = -1;
	size_t s;
	wStream* sChunk;
	UINT32 packetSize = 12;
	char chunkSize[11];
	int chunkLen = sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIx32 "\r\n", packetSize);

	if (chunkLen < 0)
		return FALSE;

	sChunk = Stream_New(NULL, (size_t)chunkLen + packetSize + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, (size_t)chunkLen);
	Stream_Write_UINT16(sChunk, PKT_TYPE_CLOSE_CHANNEL_RESPONSE); /* Type */
	Stream_Write_UINT16(sChunk, 0);                               /* Reserved */
	Stream_Write_UINT32(sChunk, packetSize);                      /* Packet length */
	Stream_Write_UINT32(sChunk, 0);                               /* Status code */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s <= INT_MAX)
		status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);

	Stream_Free(sChunk, TRUE);
	return (status < 0 ? FALSE : TRUE);
}

static BOOL rdg_process_keep_alive_packet(rdpRdg* rdg)
{
	int status = -1;
	size_t s;
	wStream* sChunk;
	size_t packetSize = 8;
	char chunkSize[11];
	int chunkLen = sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIxz "\r\n", packetSize);

	if ((chunkLen < 0) || (packetSize > UINT32_MAX))
		return FALSE;

	sChunk = Stream_New(NULL, (size_t)chunkLen + packetSize + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, (size_t)chunkLen);
	Stream_Write_UINT16(sChunk, PKT_TYPE_KEEPALIVE); /* Type */
	Stream_Write_UINT16(sChunk, 0);                  /* Reserved */
	Stream_Write_UINT32(sChunk, (UINT32)packetSize); /* Packet length */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s <= INT_MAX)
		status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);

	Stream_Free(sChunk, TRUE);
	return (status < 0 ? FALSE : TRUE);
}

static BOOL rdg_process_unknown_packet(rdpRdg* rdg, int type)
{
	WINPR_UNUSED(rdg);
	WINPR_UNUSED(type);
	WLog_WARN(TAG, "Unknown Control Packet received: %X", type);
	return TRUE;
}

static BOOL rdg_process_control_packet(rdpRdg* rdg, int type, size_t packetLength)
{
	wStream* s = NULL;
	size_t readCount = 0;
	int status;
	size_t payloadSize = packetLength - sizeof(RdgPacketHeader);

	if (packetLength < sizeof(RdgPacketHeader))
		return FALSE;

	assert(sizeof(RdgPacketHeader) < INT_MAX);

	if (payloadSize)
	{
		s = Stream_New(NULL, payloadSize);

		if (!s)
			return FALSE;

		while (readCount < payloadSize)
		{
			status =
			    BIO_read(rdg->tlsOut->bio, Stream_Pointer(s), (int)payloadSize - (int)readCount);

			if (status <= 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
				{
					Stream_Free(s, TRUE);
					return FALSE;
				}

				continue;
			}

			Stream_Seek(s, (size_t)status);
			readCount += (size_t)status;

			if (readCount > INT_MAX)
			{
				Stream_Free(s, TRUE);
				return FALSE;
			}
		}
	}

	switch (type)
	{
		case PKT_TYPE_CLOSE_CHANNEL:
			EnterCriticalSection(&rdg->writeSection);
			status = rdg_process_close_packet(rdg);
			LeaveCriticalSection(&rdg->writeSection);
			break;

		case PKT_TYPE_KEEPALIVE:
			EnterCriticalSection(&rdg->writeSection);
			status = rdg_process_keep_alive_packet(rdg);
			LeaveCriticalSection(&rdg->writeSection);
			break;

		default:
			status = rdg_process_unknown_packet(rdg, type);
			break;
	}

	Stream_Free(s, TRUE);
	return status;
}

static int rdg_read_data_packet(rdpRdg* rdg, BYTE* buffer, int size)
{
	RdgPacketHeader header;
	size_t readCount = 0;
	int readSize;
	int status;

	if (!rdg->packetRemainingCount)
	{
		assert(sizeof(RdgPacketHeader) < INT_MAX);

		while (readCount < sizeof(RdgPacketHeader))
		{
			status = BIO_read(rdg->tlsOut->bio, (BYTE*)(&header) + readCount,
			                  (int)sizeof(RdgPacketHeader) - (int)readCount);

			if (status <= 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
					return -1;

				if (!readCount)
					return 0;

				BIO_wait_read(rdg->tlsOut->bio, 50);
				continue;
			}

			readCount += (size_t)status;

			if (readCount > INT_MAX)
				return -1;
		}

		if (header.type != PKT_TYPE_DATA)
		{
			status = rdg_process_control_packet(rdg, header.type, header.packetLength);

			if (!status)
				return -1;

			return 0;
		}

		readCount = 0;

		while (readCount < 2)
		{
			status = BIO_read(rdg->tlsOut->bio, (BYTE*)(&rdg->packetRemainingCount) + readCount,
			                  2 - (int)readCount);

			if (status < 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
					return -1;

				BIO_wait_read(rdg->tlsOut->bio, 50);
				continue;
			}

			readCount += (size_t)status;
		}
	}

	readSize = (rdg->packetRemainingCount < size ? rdg->packetRemainingCount : size);
	status = BIO_read(rdg->tlsOut->bio, buffer, readSize);

	if (status <= 0)
	{
		if (!BIO_should_retry(rdg->tlsOut->bio))
		{
			return -1;
		}

		return 0;
	}

	rdg->packetRemainingCount -= status;
	return status;
}

static int rdg_bio_write(BIO* bio, const char* buf, int num)
{
	int status;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	BIO_clear_flags(bio, BIO_FLAGS_WRITE);
	EnterCriticalSection(&rdg->writeSection);
	status = rdg_write_data_packet(rdg, (const BYTE*)buf, num);
	LeaveCriticalSection(&rdg->writeSection);

	if (status < 0)
	{
		BIO_clear_flags(bio, BIO_FLAGS_SHOULD_RETRY);
		return -1;
	}
	else if (status < num)
	{
		BIO_set_flags(bio, BIO_FLAGS_WRITE);
		WSASetLastError(WSAEWOULDBLOCK);
	}
	else
	{
		BIO_set_flags(bio, BIO_FLAGS_WRITE);
	}

	return status;
}

static int rdg_bio_read(BIO* bio, char* buf, int size)
{
	int status;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	status = rdg_read_data_packet(rdg, (BYTE*)buf, size);

	if (status < 0)
	{
		BIO_clear_retry_flags(bio);
		return -1;
	}
	else if (status == 0)
	{
		BIO_set_retry_read(bio);
		WSASetLastError(WSAEWOULDBLOCK);
		return -1;
	}
	else
	{
		BIO_set_flags(bio, BIO_FLAGS_READ);
	}

	return status;
}

static int rdg_bio_puts(BIO* bio, const char* str)
{
	WINPR_UNUSED(bio);
	WINPR_UNUSED(str);
	return -2;
}

static int rdg_bio_gets(BIO* bio, char* str, int size)
{
	WINPR_UNUSED(bio);
	WINPR_UNUSED(str);
	WINPR_UNUSED(size);
	return -2;
}

static long rdg_bio_ctrl(BIO* bio, int cmd, long arg1, void* arg2)
{
	long status = -1;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	rdpTls* tlsOut = rdg->tlsOut;
	rdpTls* tlsIn = rdg->tlsIn;

	if (cmd == BIO_CTRL_FLUSH)
	{
		(void)BIO_flush(tlsOut->bio);
		(void)BIO_flush(tlsIn->bio);
		status = 1;
	}
	else if (cmd == BIO_C_SET_NONBLOCK)
	{
		status = 1;
	}
	else if (cmd == BIO_C_READ_BLOCKED)
	{
		BIO* bio = tlsOut->bio;
		status = BIO_read_blocked(bio);
	}
	else if (cmd == BIO_C_WRITE_BLOCKED)
	{
		BIO* bio = tlsIn->bio;
		status = BIO_write_blocked(bio);
	}
	else if (cmd == BIO_C_WAIT_READ)
	{
		int timeout = (int)arg1;
		BIO* bio = tlsOut->bio;

		if (BIO_read_blocked(bio))
			return BIO_wait_read(bio, timeout);
		else if (BIO_write_blocked(bio))
			return BIO_wait_write(bio, timeout);
		else
			status = 1;
	}
	else if (cmd == BIO_C_WAIT_WRITE)
	{
		int timeout = (int)arg1;
		BIO* bio = tlsIn->bio;

		if (BIO_write_blocked(bio))
			status = BIO_wait_write(bio, timeout);
		else if (BIO_read_blocked(bio))
			status = BIO_wait_read(bio, timeout);
		else
			status = 1;
	}
	else if (cmd == BIO_C_GET_EVENT || cmd == BIO_C_GET_FD)
	{
		/*
		 * A note about BIO_C_GET_FD:
		 * Even if two FDs are part of RDG, only one FD can be returned here.
		 *
		 * In FreeRDP, BIO FDs are only used for polling, so it is safe to use the outgoing FD only
		 *
		 * See issue #3602
		 */
		status = BIO_ctrl(tlsOut->bio, cmd, arg1, arg2);
	}

	return status;
}

static int rdg_bio_new(BIO* bio)
{
	BIO_set_init(bio, 1);
	BIO_set_flags(bio, BIO_FLAGS_SHOULD_RETRY);
	return 1;
}

static int rdg_bio_free(BIO* bio)
{
	WINPR_UNUSED(bio);
	return 1;
}

static BIO_METHOD* BIO_s_rdg(void)
{
	static BIO_METHOD* bio_methods = NULL;

	if (bio_methods == NULL)
	{
		if (!(bio_methods = BIO_meth_new(BIO_TYPE_TSG, "RDGateway")))
			return NULL;

		BIO_meth_set_write(bio_methods, rdg_bio_write);
		BIO_meth_set_read(bio_methods, rdg_bio_read);
		BIO_meth_set_puts(bio_methods, rdg_bio_puts);
		BIO_meth_set_gets(bio_methods, rdg_bio_gets);
		BIO_meth_set_ctrl(bio_methods, rdg_bio_ctrl);
		BIO_meth_set_create(bio_methods, rdg_bio_new);
		BIO_meth_set_destroy(bio_methods, rdg_bio_free);
	}

	return bio_methods;
}

rdpRdg* rdg_new(rdpContext* context)
{
	rdpRdg* rdg;
	RPC_CSTR stringUuid;
	char bracedUuid[40];
	RPC_STATUS rpcStatus;

	if (!context)
		return NULL;

	rdg = (rdpRdg*)calloc(1, sizeof(rdpRdg));

	if (rdg)
	{
		rdg->state = RDG_CLIENT_STATE_INITIAL;
		rdg->context = context;
		rdg->settings = rdg->context->settings;
		rdg->extAuth = HTTP_EXTENDED_AUTH_NONE;

		if (rdg->settings->GatewayAccessToken)
			rdg->extAuth = HTTP_EXTENDED_AUTH_PAA;

		UuidCreate(&rdg->guid);
		rpcStatus = UuidToStringA(&rdg->guid, &stringUuid);

		if (rpcStatus == RPC_S_OUT_OF_MEMORY)
			goto rdg_alloc_error;

		sprintf_s(bracedUuid, sizeof(bracedUuid), "{%s}", stringUuid);
		RpcStringFreeA(&stringUuid);
		rdg->tlsOut = tls_new(rdg->settings);

		if (!rdg->tlsOut)
			goto rdg_alloc_error;

		rdg->tlsIn = tls_new(rdg->settings);

		if (!rdg->tlsIn)
			goto rdg_alloc_error;

		rdg->http = http_context_new();

		if (!rdg->http)
			goto rdg_alloc_error;

		if (!http_context_set_uri(rdg->http, "/remoteDesktopGateway/") ||
		    !http_context_set_accept(rdg->http, "*/*") ||
		    !http_context_set_cache_control(rdg->http, "no-cache") ||
		    !http_context_set_pragma(rdg->http, "no-cache") ||
		    !http_context_set_connection(rdg->http, "Keep-Alive") ||
		    !http_context_set_user_agent(rdg->http, "MS-RDGateway/1.0") ||
		    !http_context_set_host(rdg->http, rdg->settings->GatewayHostname) ||
		    !http_context_set_rdg_connection_id(rdg->http, bracedUuid))
		{
			goto rdg_alloc_error;
		}

		if (rdg->extAuth != HTTP_EXTENDED_AUTH_NONE)
		{
			switch (rdg->extAuth)
			{
				case HTTP_EXTENDED_AUTH_PAA:
					if (!http_context_set_rdg_auth_scheme(rdg->http, "PAA"))
						goto rdg_alloc_error;

					break;

				default:
					WLog_DBG(TAG, "RDG extended authentication method %d not supported",
					         rdg->extAuth);
			}
		}

		rdg->frontBio = BIO_new(BIO_s_rdg());

		if (!rdg->frontBio)
			goto rdg_alloc_error;

		BIO_set_data(rdg->frontBio, rdg);
		InitializeCriticalSection(&rdg->writeSection);
	}

	return rdg;
rdg_alloc_error:
	rdg_free(rdg);
	return NULL;
}

void rdg_free(rdpRdg* rdg)
{
	if (!rdg)
		return;

	tls_free(rdg->tlsOut);
	tls_free(rdg->tlsIn);
	http_context_free(rdg->http);
	ntlm_free(rdg->ntlm);

	if (!rdg->attached)
		BIO_free_all(rdg->frontBio);

	DeleteCriticalSection(&rdg->writeSection);
	free(rdg);
}

BIO* rdg_get_front_bio_and_take_ownership(rdpRdg* rdg)
{
	if (!rdg)
		return NULL;

	rdg->attached = TRUE;
	return rdg->frontBio;
}


Fixed version (ground truth):
/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Remote Desktop Gateway (RDG)
 *
 * Copyright 2015 Denis Vincent <dvincent@devolutions.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <assert.h>

#include <winpr/crt.h>
#include <winpr/synch.h>
#include <winpr/print.h>
#include <winpr/stream.h>
#include <winpr/winsock.h>

#include <freerdp/log.h>
#include <freerdp/error.h>
#include <freerdp/utils/ringbuffer.h>

#include "rdg.h"
#include "../proxy.h"
#include "../rdp.h"
#include "../../crypto/opensslcompat.h"
#include "rpc_fault.h"

#define TAG FREERDP_TAG("core.gateway.rdg")

/* HTTP channel response fields present flags. */
#define HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID 0x1
#define HTTP_CHANNEL_RESPONSE_OPTIONAL 0x2
#define HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT 0x4

/* HTTP extended auth. */
#define HTTP_EXTENDED_AUTH_NONE 0x0
#define HTTP_EXTENDED_AUTH_SC 0x1         /* Smart card authentication. */
#define HTTP_EXTENDED_AUTH_PAA 0x02       /* Pluggable authentication. */
#define HTTP_EXTENDED_AUTH_SSPI_NTLM 0x04 /* NTLM extended authentication. */

/* HTTP packet types. */
#define PKT_TYPE_HANDSHAKE_REQUEST 0x1
#define PKT_TYPE_HANDSHAKE_RESPONSE 0x2
#define PKT_TYPE_EXTENDED_AUTH_MSG 0x3
#define PKT_TYPE_TUNNEL_CREATE 0x4
#define PKT_TYPE_TUNNEL_RESPONSE 0x5
#define PKT_TYPE_TUNNEL_AUTH 0x6
#define PKT_TYPE_TUNNEL_AUTH_RESPONSE 0x7
#define PKT_TYPE_CHANNEL_CREATE 0x8
#define PKT_TYPE_CHANNEL_RESPONSE 0x9
#define PKT_TYPE_DATA 0xA
#define PKT_TYPE_SERVICE_MESSAGE 0xB
#define PKT_TYPE_REAUTH_MESSAGE 0xC
#define PKT_TYPE_KEEPALIVE 0xD
#define PKT_TYPE_CLOSE_CHANNEL 0x10
#define PKT_TYPE_CLOSE_CHANNEL_RESPONSE 0x11

/* HTTP tunnel auth fields present flags. */
#define HTTP_TUNNEL_AUTH_FIELD_SOH 0x1

/* HTTP tunnel auth response fields present flags. */
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS 0x1
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT 0x2
#define HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE 0x4

/* HTTP tunnel packet fields present flags. */
#define HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE 0x1
#define HTTP_TUNNEL_PACKET_FIELD_REAUTH 0x2

/* HTTP tunnel redir flags. */
#define HTTP_TUNNEL_REDIR_ENABLE_ALL 0x80000000
#define HTTP_TUNNEL_REDIR_DISABLE_ALL 0x40000000
#define HTTP_TUNNEL_REDIR_DISABLE_DRIVE 0x1
#define HTTP_TUNNEL_REDIR_DISABLE_PRINTER 0x2
#define HTTP_TUNNEL_REDIR_DISABLE_PORT 0x4
#define HTTP_TUNNEL_REDIR_DISABLE_CLIPBOARD 0x8
#define HTTP_TUNNEL_REDIR_DISABLE_PNP 0x10

/* HTTP tunnel response fields present flags. */
#define HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID 0x1
#define HTTP_TUNNEL_RESPONSE_FIELD_CAPS 0x2
#define HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ 0x4
#define HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG 0x10

/* HTTP capability type enumeration. */
#define HTTP_CAPABILITY_TYPE_QUAR_SOH 0x1
#define HTTP_CAPABILITY_IDLE_TIMEOUT 0x2
#define HTTP_CAPABILITY_MESSAGING_CONSENT_SIGN 0x4
#define HTTP_CAPABILITY_MESSAGING_SERVICE_MSG 0x8
#define HTTP_CAPABILITY_REAUTH 0x10
#define HTTP_CAPABILITY_UDP_TRANSPORT 0x20

struct rdp_rdg
{
	rdpContext* context;
	rdpSettings* settings;
	BOOL attached;
	BIO* frontBio;
	rdpTls* tlsIn;
	rdpTls* tlsOut;
	rdpNtlm* ntlm;
	HttpContext* http;
	CRITICAL_SECTION writeSection;

	UUID guid;

	int state;
	UINT16 packetRemainingCount;
	UINT16 reserved1;
	int timeout;
	UINT16 extAuth;
	UINT16 reserved2;
};

enum
{
	RDG_CLIENT_STATE_INITIAL,
	RDG_CLIENT_STATE_HANDSHAKE,
	RDG_CLIENT_STATE_TUNNEL_CREATE,
	RDG_CLIENT_STATE_TUNNEL_AUTHORIZE,
	RDG_CLIENT_STATE_CHANNEL_CREATE,
	RDG_CLIENT_STATE_OPENED,
};

#pragma pack(push, 1)

typedef struct rdg_packet_header
{
	UINT16 type;
	UINT16 reserved;
	UINT32 packetLength;
} RdgPacketHeader;

#pragma pack(pop)

typedef struct
{
	UINT32 code;
	const char* name;
} t_err_mapping;

static const t_err_mapping tunnel_response_fields_present[] = {
	{ HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID, "HTTP_TUNNEL_RESPONSE_FIELD_TUNNEL_ID" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_CAPS, "HTTP_TUNNEL_RESPONSE_FIELD_CAPS" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ, "HTTP_TUNNEL_RESPONSE_FIELD_SOH_REQ" },
	{ HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG, "HTTP_TUNNEL_RESPONSE_FIELD_CONSENT_MSG" }
};

static const t_err_mapping channel_response_fields_present[] = {
	{ HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID, "HTTP_CHANNEL_RESPONSE_FIELD_CHANNELID" },
	{ HTTP_CHANNEL_RESPONSE_OPTIONAL, "HTTP_CHANNEL_RESPONSE_OPTIONAL" },
	{ HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT, "HTTP_CHANNEL_RESPONSE_FIELD_UDPPORT" }
};

static const t_err_mapping tunnel_authorization_response_fields_present[] = {
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS, "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_REDIR_FLAGS" },
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT,
	  "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_IDLE_TIMEOUT" },
	{ HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE,
	  "HTTP_TUNNEL_AUTH_RESPONSE_FIELD_SOH_RESPONSE" }
};

static const t_err_mapping extended_auth[] = {
	{ HTTP_EXTENDED_AUTH_NONE, "HTTP_EXTENDED_AUTH_NONE" },
	{ HTTP_EXTENDED_AUTH_SC, "HTTP_EXTENDED_AUTH_SC" },
	{ HTTP_EXTENDED_AUTH_PAA, "HTTP_EXTENDED_AUTH_PAA" },
	{ HTTP_EXTENDED_AUTH_SSPI_NTLM, "HTTP_EXTENDED_AUTH_SSPI_NTLM" }
};

static const char* fields_present_to_string(UINT16 fieldsPresent, const t_err_mapping* map,
                                            size_t elements)
{
	size_t x = 0;
	static char buffer[1024] = { 0 };
	char fields[12];
	memset(buffer, 0, sizeof(buffer));

	for (x = 0; x < elements; x++)
	{
		if (buffer[0] != '\0')
			strcat(buffer, "|");

		if ((map[x].code & fieldsPresent) != 0)
			strcat(buffer, map[x].name);
	}

	sprintf_s(fields, ARRAYSIZE(fields), " [%04" PRIx16 "]", fieldsPresent);
	strcat(buffer, fields);
	return buffer;
}

static const char* channel_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, channel_response_fields_present,
	                                ARRAYSIZE(channel_response_fields_present));
}

static const char* tunnel_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, tunnel_response_fields_present,
	                                ARRAYSIZE(tunnel_response_fields_present));
}

static const char* tunnel_authorization_response_fields_present_to_string(UINT16 fieldsPresent)
{
	return fields_present_to_string(fieldsPresent, tunnel_authorization_response_fields_present,
	                                ARRAYSIZE(tunnel_authorization_response_fields_present));
}

static const char* extended_auth_to_string(UINT16 auth)
{
	if (auth == HTTP_EXTENDED_AUTH_NONE)
		return "HTTP_EXTENDED_AUTH_NONE [0x0000]";

	return fields_present_to_string(auth, extended_auth, ARRAYSIZE(extended_auth));
}

static BOOL rdg_write_packet(rdpRdg* rdg, wStream* sPacket)
{
	size_t s;
	int status;
	wStream* sChunk;
	char chunkSize[11];
	sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIXz "\r\n", Stream_Length(sPacket));
	sChunk = Stream_New(NULL, strnlen(chunkSize, sizeof(chunkSize)) + Stream_Length(sPacket) + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, strnlen(chunkSize, sizeof(chunkSize)));
	Stream_Write(sChunk, Stream_Buffer(sPacket), Stream_Length(sPacket));
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s > INT_MAX)
		return FALSE;

	status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);
	Stream_Free(sChunk, TRUE);

	if (status < 0)
		return FALSE;

	return TRUE;
}

static BOOL rdg_read_all(rdpTls* tls, BYTE* buffer, int size)
{
	int status;
	int readCount = 0;
	BYTE* pBuffer = buffer;

	while (readCount < size)
	{
		status = BIO_read(tls->bio, pBuffer, size - readCount);

		if (status <= 0)
		{
			if (!BIO_should_retry(tls->bio))
				return FALSE;

			continue;
		}

		readCount += status;
		pBuffer += status;
	}

	return TRUE;
}

static wStream* rdg_receive_packet(rdpRdg* rdg)
{
	wStream* s;
	const size_t header = sizeof(RdgPacketHeader);
	size_t packetLength;
	assert(header <= INT_MAX);
	s = Stream_New(NULL, 1024);

	if (!s)
		return NULL;

	if (!rdg_read_all(rdg->tlsOut, Stream_Buffer(s), header))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	Stream_Seek(s, 4);
	Stream_Read_UINT32(s, packetLength);

	if ((packetLength > INT_MAX) || !Stream_EnsureCapacity(s, packetLength) ||
	    (packetLength < header))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	if (!rdg_read_all(rdg->tlsOut, Stream_Buffer(s) + header, (int)packetLength - (int)header))
	{
		Stream_Free(s, TRUE);
		return NULL;
	}

	Stream_SetLength(s, packetLength);
	return s;
}

static BOOL rdg_send_handshake(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	s = Stream_New(NULL, 14);

	if (!s)
		return FALSE;

	Stream_Write_UINT16(s, PKT_TYPE_HANDSHAKE_REQUEST); /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                          /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, 14);                         /* PacketLength (4 bytes) */
	Stream_Write_UINT8(s, 1);                           /* VersionMajor (1 byte) */
	Stream_Write_UINT8(s, 0);                           /* VersionMinor (1 byte) */
	Stream_Write_UINT16(s, 0);                          /* ClientVersion (2 bytes), must be 0 */
	Stream_Write_UINT16(s, rdg->extAuth);               /* ExtendedAuthentication (2 bytes) */
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_HANDSHAKE;
	}

	return status;
}

static BOOL rdg_send_tunnel_request(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	UINT32 packetSize = 16;
	UINT16 fieldsPresent = 0;
	WCHAR* PAACookie = NULL;
	int PAACookieLen = 0;

	if (rdg->extAuth == HTTP_EXTENDED_AUTH_PAA)
	{
		PAACookieLen =
		    ConvertToUnicode(CP_UTF8, 0, rdg->settings->GatewayAccessToken, -1, &PAACookie, 0);

		if (!PAACookie || (PAACookieLen < 0) || (PAACookieLen > UINT16_MAX / 2))
		{
			free(PAACookie);
			return FALSE;
		}

		packetSize += 2 + (UINT32)PAACookieLen * sizeof(WCHAR);
		fieldsPresent = HTTP_TUNNEL_PACKET_FIELD_PAA_COOKIE;
	}

	s = Stream_New(NULL, packetSize);

	if (!s)
	{
		free(PAACookie);
		return FALSE;
	}

	Stream_Write_UINT16(s, PKT_TYPE_TUNNEL_CREATE);        /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                             /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);                    /* PacketLength (4 bytes) */
	Stream_Write_UINT32(s, HTTP_CAPABILITY_TYPE_QUAR_SOH); /* CapabilityFlags (4 bytes) */
	Stream_Write_UINT16(s, fieldsPresent);                 /* FieldsPresent (2 bytes) */
	Stream_Write_UINT16(s, 0);                             /* Reserved (2 bytes), must be 0 */

	if (PAACookie)
	{
		Stream_Write_UINT16(s, (UINT16)PAACookieLen * 2); /* PAA cookie string length */
		Stream_Write_UTF16_String(s, PAACookie, (size_t)PAACookieLen);
	}

	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);
	free(PAACookie);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_TUNNEL_CREATE;
	}

	return status;
}

static BOOL rdg_send_tunnel_authorization(rdpRdg* rdg)
{
	wStream* s;
	BOOL status;
	WCHAR* clientName = NULL;
	UINT32 packetSize;
	int clientNameLen =
	    ConvertToUnicode(CP_UTF8, 0, rdg->settings->ClientHostname, -1, &clientName, 0);

	if (!clientName || (clientNameLen < 0) || (clientNameLen > UINT16_MAX / 2))
	{
		free(clientName);
		return FALSE;
	}

	packetSize = 12 + (UINT32)clientNameLen * sizeof(WCHAR);
	s = Stream_New(NULL, packetSize);

	if (!s)
	{
		free(clientName);
		return FALSE;
	}

	Stream_Write_UINT16(s, PKT_TYPE_TUNNEL_AUTH);      /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                         /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);                /* PacketLength (4 bytes) */
	Stream_Write_UINT16(s, 0);                         /* FieldsPresent (2 bytes) */
	Stream_Write_UINT16(s, (UINT16)clientNameLen * 2); /* Client name string length */
	Stream_Write_UTF16_String(s, clientName, (size_t)clientNameLen);
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
	Stream_Free(s, TRUE);
	free(clientName);

	if (status)
	{
		rdg->state = RDG_CLIENT_STATE_TUNNEL_AUTHORIZE;
	}

	return status;
}

static BOOL rdg_send_channel_create(rdpRdg* rdg)
{
	wStream* s = NULL;
	BOOL status = FALSE;
	WCHAR* serverName = NULL;
	int serverNameLen =
	    ConvertToUnicode(CP_UTF8, 0, rdg->settings->ServerHostname, -1, &serverName, 0);
	UINT32 packetSize = 16 + ((UINT32)serverNameLen) * 2;

	if ((serverNameLen < 0) || (serverNameLen > UINT16_MAX / 2))
		goto fail;

	s = Stream_New(NULL, packetSize);

	if (!s)
		goto fail;

	Stream_Write_UINT16(s, PKT_TYPE_CHANNEL_CREATE); /* Type (2 bytes) */
	Stream_Write_UINT16(s, 0);                       /* Reserved (2 bytes) */
	Stream_Write_UINT32(s, packetSize);              /* PacketLength (4 bytes) */
	Stream_Write_UINT8(s, 1);                        /* Number of resources. (1 byte) */
	Stream_Write_UINT8(s, 0);                        /* Number of alternative resources (1 byte) */
	Stream_Write_UINT16(s, (UINT16)rdg->settings->ServerPort); /* Resource port (2 bytes) */
	Stream_Write_UINT16(s, 3);                                 /* Protocol number (2 bytes) */
	Stream_Write_UINT16(s, (UINT16)serverNameLen * 2);
	Stream_Write_UTF16_String(s, serverName, (size_t)serverNameLen);
	Stream_SealLength(s);
	status = rdg_write_packet(rdg, s);
fail:
	free(serverName);
	Stream_Free(s, TRUE);

	if (status)
		rdg->state = RDG_CLIENT_STATE_CHANNEL_CREATE;

	return status;
}

static BOOL rdg_set_ntlm_auth_header(rdpNtlm* ntlm, HttpRequest* request)
{
	const SecBuffer* ntlmToken = ntlm_client_get_output_buffer(ntlm);
	char* base64NtlmToken = NULL;

	if (ntlmToken)
	{
		if (ntlmToken->cbBuffer > INT_MAX)
			return FALSE;

		base64NtlmToken = crypto_base64_encode(ntlmToken->pvBuffer, (int)ntlmToken->cbBuffer);
	}

	if (base64NtlmToken)
	{
		BOOL rc = http_request_set_auth_scheme(request, "NTLM") &&
		          http_request_set_auth_param(request, base64NtlmToken);
		free(base64NtlmToken);

		if (!rc)
			return FALSE;
	}

	return TRUE;
}

static wStream* rdg_build_http_request(rdpRdg* rdg, const char* method,
                                       const char* transferEncoding)
{
	wStream* s = NULL;
	HttpRequest* request = NULL;
	const char* uri;

	if (!rdg || !method)
		return NULL;

	uri = http_context_get_uri(rdg->http);
	request = http_request_new();

	if (!request)
		return NULL;

	if (!http_request_set_method(request, method) || !http_request_set_uri(request, uri))
		goto out;

	if (rdg->ntlm)
	{
		if (!rdg_set_ntlm_auth_header(rdg->ntlm, request))
			goto out;
	}

	if (transferEncoding)
	{
		http_request_set_transfer_encoding(request, transferEncoding);
	}

	s = http_request_write(rdg->http, request);
out:
	http_request_free(request);

	if (s)
		Stream_SealLength(s);

	return s;
}

static BOOL rdg_handle_ntlm_challenge(rdpNtlm* ntlm, HttpResponse* response)
{
	BOOL continueNeeded = FALSE;
	size_t len;
	const char* token64 = NULL;
	int ntlmTokenLength = 0;
	BYTE* ntlmTokenData = NULL;
	long StatusCode;

	if (!ntlm || !response)
		return FALSE;

	StatusCode = http_response_get_status_code(response);

	if (StatusCode != HTTP_STATUS_DENIED)
	{
		WLog_DBG(TAG, "Unexpected NTLM challenge HTTP status: %ld", StatusCode);
		return FALSE;
	}

	token64 = http_response_get_auth_token(response, "NTLM");

	if (!token64)
		return FALSE;

	len = strlen(token64);

	if (len > INT_MAX)
		return FALSE;

	crypto_base64_decode(token64, (int)len, &ntlmTokenData, &ntlmTokenLength);

	if (ntlmTokenLength < 0)
	{
		free(ntlmTokenData);
		return FALSE;
	}

	if (ntlmTokenData && ntlmTokenLength)
	{
		if (!ntlm_client_set_input_buffer(ntlm, FALSE, ntlmTokenData, (size_t)ntlmTokenLength))
			return FALSE;
	}

	if (!ntlm_authenticate(ntlm, &continueNeeded))
		return FALSE;

	if (continueNeeded)
		return FALSE;

	return TRUE;
}

static BOOL rdg_skip_seed_payload(rdpTls* tls, SSIZE_T lastResponseLength)
{
	BYTE seed_payload[10];
	const size_t size = sizeof(seed_payload);

	assert(size < SSIZE_MAX);

	/* Per [MS-TSGU] 3.3.5.1 step 4, after final OK response RDG server sends
	 * random "seed" payload of limited size. In practice it's 10 bytes.
	 */
	if (lastResponseLength < (SSIZE_T)size)
	{
		if (!rdg_read_all(tls, seed_payload, size - lastResponseLength))
		{
			return FALSE;
		}
	}

	return TRUE;
}

static BOOL rdg_process_handshake_response(rdpRdg* rdg, wStream* s)
{
	UINT32 errorCode;
	UINT16 serverVersion, extendedAuth;
	BYTE verMajor, verMinor;
	const char* error;
	WLog_DBG(TAG, "Handshake response received");

	if (rdg->state != RDG_CLIENT_STATE_HANDSHAKE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 10)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 10", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT8(s, verMajor);
	Stream_Read_UINT8(s, verMinor);
	Stream_Read_UINT16(s, serverVersion);
	Stream_Read_UINT16(s, extendedAuth);
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG,
	         "errorCode=%s, verMajor=%" PRId8 ", verMinor=%" PRId8 ", serverVersion=%" PRId16
	         ", extendedAuth=%s",
	         error, verMajor, verMinor, serverVersion, extended_auth_to_string(extendedAuth));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Handshake error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_tunnel_request(rdg);
}

static BOOL rdg_process_tunnel_response(rdpRdg* rdg, wStream* s)
{
	UINT16 serverVersion, fieldsPresent;
	UINT32 errorCode;
	const char* error;
	WLog_DBG(TAG, "Tunnel response received");

	if (rdg->state != RDG_CLIENT_STATE_TUNNEL_CREATE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 10)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 10", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT16(s, serverVersion);
	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "serverVersion=%" PRId16 ", errorCode=%s, fieldsPresent=%s", serverVersion, error,
	         tunnel_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Tunnel creation error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_tunnel_authorization(rdg);
}

static BOOL rdg_process_tunnel_authorization_response(rdpRdg* rdg, wStream* s)
{
	UINT32 errorCode;
	UINT16 fieldsPresent;
	const char* error;
	WLog_DBG(TAG, "Tunnel authorization received");

	if (rdg->state != RDG_CLIENT_STATE_TUNNEL_AUTHORIZE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "errorCode=%s, fieldsPresent=%s", error,
	         tunnel_authorization_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "Tunnel authorization error %s", error);
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	return rdg_send_channel_create(rdg);
}

static BOOL rdg_process_channel_response(rdpRdg* rdg, wStream* s)
{
	UINT16 fieldsPresent;
	UINT32 errorCode;
	const char* error;
	WLog_DBG(TAG, "Channel response received");

	if (rdg->state != RDG_CLIENT_STATE_CHANNEL_CREATE)
	{
		return FALSE;
	}

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT32(s, errorCode);
	Stream_Read_UINT16(s, fieldsPresent);
	Stream_Seek_UINT16(s); /* reserved */
	error = rpc_error_to_string(errorCode);
	WLog_DBG(TAG, "channel response errorCode=%s, fieldsPresent=%s", error,
	         channel_response_fields_present_to_string(fieldsPresent));

	if (FAILED(errorCode))
	{
		WLog_ERR(TAG, "channel response errorCode=%s, fieldsPresent=%s", error,
		         channel_response_fields_present_to_string(fieldsPresent));
		freerdp_set_last_error_log(rdg->context, errorCode);
		return FALSE;
	}

	rdg->state = RDG_CLIENT_STATE_OPENED;
	return TRUE;
}

static BOOL rdg_process_packet(rdpRdg* rdg, wStream* s)
{
	BOOL status = TRUE;
	UINT16 type;
	UINT32 packetLength;
	Stream_SetPosition(s, 0);

	if (Stream_GetRemainingLength(s) < 8)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected 8", __FUNCTION__,
		         Stream_GetRemainingLength(s));
		return FALSE;
	}

	Stream_Read_UINT16(s, type);
	Stream_Seek_UINT16(s); /* reserved */
	Stream_Read_UINT32(s, packetLength);

	if (Stream_Length(s) < packetLength)
	{
		WLog_ERR(TAG, "[%s] Short packet %" PRIuz ", expected %" PRIuz, __FUNCTION__,
		         Stream_Length(s), packetLength);
		return FALSE;
	}

	switch (type)
	{
		case PKT_TYPE_HANDSHAKE_RESPONSE:
			status = rdg_process_handshake_response(rdg, s);
			break;

		case PKT_TYPE_TUNNEL_RESPONSE:
			status = rdg_process_tunnel_response(rdg, s);
			break;

		case PKT_TYPE_TUNNEL_AUTH_RESPONSE:
			status = rdg_process_tunnel_authorization_response(rdg, s);
			break;

		case PKT_TYPE_CHANNEL_RESPONSE:
			status = rdg_process_channel_response(rdg, s);
			break;

		case PKT_TYPE_DATA:
			WLog_ERR(TAG, "[%s] Unexpected packet type DATA", __FUNCTION__);
			return FALSE;
	}

	return status;
}

DWORD rdg_get_event_handles(rdpRdg* rdg, HANDLE* events, DWORD count)
{
	DWORD nCount = 0;
	assert(rdg != NULL);

	if (rdg->tlsOut && rdg->tlsOut->bio)
	{
		if (events && (nCount < count))
		{
			BIO_get_event(rdg->tlsOut->bio, &events[nCount]);
			nCount++;
		}
		else
			return 0;
	}

	if (rdg->tlsIn && rdg->tlsIn->bio)
	{
		if (events && (nCount < count))
		{
			BIO_get_event(rdg->tlsIn->bio, &events[nCount]);
			nCount++;
		}
		else
			return 0;
	}

	return nCount;
}

static BOOL rdg_get_gateway_credentials(rdpContext* context)
{
	rdpSettings* settings = context->settings;
	freerdp* instance = context->instance;

	if (!settings->GatewayPassword || !settings->GatewayUsername ||
	    !strlen(settings->GatewayPassword) || !strlen(settings->GatewayUsername))
	{
		if (freerdp_shall_disconnect(instance))
			return FALSE;

		if (!instance->GatewayAuthenticate)
		{
			freerdp_set_last_error_log(context, FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
			return FALSE;
		}
		else
		{
			BOOL proceed =
			    instance->GatewayAuthenticate(instance, &settings->GatewayUsername,
			                                  &settings->GatewayPassword, &settings->GatewayDomain);

			if (!proceed)
			{
				freerdp_set_last_error_log(context,
				                           FREERDP_ERROR_CONNECT_NO_OR_MISSING_CREDENTIALS);
				return FALSE;
			}

			if (settings->GatewayUseSameCredentials)
			{
				if (settings->GatewayUsername)
				{
					free(settings->Username);

					if (!(settings->Username = _strdup(settings->GatewayUsername)))
						return FALSE;
				}

				if (settings->GatewayDomain)
				{
					free(settings->Domain);

					if (!(settings->Domain = _strdup(settings->GatewayDomain)))
						return FALSE;
				}

				if (settings->GatewayPassword)
				{
					free(settings->Password);

					if (!(settings->Password = _strdup(settings->GatewayPassword)))
						return FALSE;
				}
			}
		}
	}

	return TRUE;
}

static BOOL rdg_ntlm_init(rdpRdg* rdg, rdpTls* tls)
{
	BOOL continueNeeded = FALSE;
	rdpContext* context = rdg->context;
	rdpSettings* settings = context->settings;
	rdg->ntlm = ntlm_new();

	if (!rdg->ntlm)
		return FALSE;

	if (!rdg_get_gateway_credentials(context))
		return FALSE;

	if (!ntlm_client_init(rdg->ntlm, TRUE, settings->GatewayUsername, settings->GatewayDomain,
	                      settings->GatewayPassword, tls->Bindings))
		return FALSE;

	if (!ntlm_client_make_spn(rdg->ntlm, _T("HTTP"), settings->GatewayHostname))
		return FALSE;

	if (!ntlm_authenticate(rdg->ntlm, &continueNeeded))
		return FALSE;

	return continueNeeded;
}

static BOOL rdg_send_http_request(rdpRdg* rdg, rdpTls* tls, const char* method,
                                  const char* transferEncoding)
{
	size_t sz;
	wStream* s = NULL;
	int status = -1;
	s = rdg_build_http_request(rdg, method, transferEncoding);

	if (!s)
		return FALSE;

	sz = Stream_Length(s);

	if (sz <= INT_MAX)
		status = tls_write_all(tls, Stream_Buffer(s), (int)sz);

	Stream_Free(s, TRUE);
	return (status >= 0);
}

static BOOL rdg_tls_connect(rdpRdg* rdg, rdpTls* tls, const char* peerAddress, int timeout)
{
	int sockfd = 0;
	long status = 0;
	BIO* socketBio = NULL;
	BIO* bufferedBio = NULL;
	rdpSettings* settings = rdg->settings;
	const char* peerHostname = settings->GatewayHostname;
	UINT16 peerPort = (UINT16)settings->GatewayPort;
	const char *proxyUsername, *proxyPassword;
	BOOL isProxyConnection =
	    proxy_prepare(settings, &peerHostname, &peerPort, &proxyUsername, &proxyPassword);

	if (settings->GatewayPort > UINT16_MAX)
		return FALSE;

	sockfd = freerdp_tcp_connect(rdg->context, settings, peerAddress ? peerAddress : peerHostname,
	                             peerPort, timeout);

	if (sockfd < 0)
	{
		return FALSE;
	}

	socketBio = BIO_new(BIO_s_simple_socket());

	if (!socketBio)
	{
		closesocket((SOCKET)sockfd);
		return FALSE;
	}

	BIO_set_fd(socketBio, sockfd, BIO_CLOSE);
	bufferedBio = BIO_new(BIO_s_buffered_socket());

	if (!bufferedBio)
	{
		BIO_free_all(socketBio);
		return FALSE;
	}

	bufferedBio = BIO_push(bufferedBio, socketBio);
	status = BIO_set_nonblock(bufferedBio, TRUE);

	if (isProxyConnection)
	{
		if (!proxy_connect(settings, bufferedBio, proxyUsername, proxyPassword,
		                   settings->GatewayHostname, (UINT16)settings->GatewayPort))
		{
			BIO_free_all(bufferedBio);
			return FALSE;
		}
	}

	if (!status)
	{
		BIO_free_all(bufferedBio);
		return FALSE;
	}

	tls->hostname = settings->GatewayHostname;
	tls->port = (int)settings->GatewayPort;
	tls->isGatewayTransport = TRUE;
	status = tls_connect(tls, bufferedBio);
	if (status < 1)
	{
		rdpContext* context = rdg->context;
		if (status < 0)
		{
			freerdp_set_last_error_if_not(context, FREERDP_ERROR_TLS_CONNECT_FAILED);
		}
		else
		{
			freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_CANCELLED);
		}

		return FALSE;
	}
	return (status >= 1);
}

static BOOL rdg_establish_data_connection(rdpRdg* rdg, rdpTls* tls, const char* method,
                                          const char* peerAddress, int timeout, BOOL* rpcFallback)
{
	HttpResponse* response = NULL;
	long statusCode;
	SSIZE_T bodyLength;
	long StatusCode;

	if (!rdg_tls_connect(rdg, tls, peerAddress, timeout))
		return FALSE;

	if (rdg->extAuth == HTTP_EXTENDED_AUTH_NONE)
	{
		if (!rdg_ntlm_init(rdg, tls))
			return FALSE;

		if (!rdg_send_http_request(rdg, tls, method, NULL))
			return FALSE;

		response = http_response_recv(tls, TRUE);

		if (!response)
			return FALSE;

		StatusCode = http_response_get_status_code(response);

		switch (StatusCode)
		{
			case HTTP_STATUS_NOT_FOUND:
			{
				WLog_INFO(TAG, "RD Gateway does not support HTTP transport.");

				if (rpcFallback)
					*rpcFallback = TRUE;

				http_response_free(response);
				return FALSE;
			}
			default:
				break;
		}

		if (!rdg_handle_ntlm_challenge(rdg->ntlm, response))
		{
			http_response_free(response);
			return FALSE;
		}

		http_response_free(response);
	}

	if (!rdg_send_http_request(rdg, tls, method, NULL))
		return FALSE;

	ntlm_free(rdg->ntlm);
	rdg->ntlm = NULL;
	response = http_response_recv(tls, TRUE);

	if (!response)
		return FALSE;

	statusCode = http_response_get_status_code(response);
	bodyLength = http_response_get_body_length(response);
	http_response_free(response);
	WLog_DBG(TAG, "%s authorization result: %d", method, statusCode);

	switch (statusCode)
	{
		case HTTP_STATUS_OK:
			break;
		case HTTP_STATUS_DENIED:
			freerdp_set_last_error_log(rdg->context, FREERDP_ERROR_CONNECT_ACCESS_DENIED);
			return FALSE;
		default:
			return FALSE;
	}

	if (strcmp(method, "RDG_OUT_DATA") == 0)
	{
		if (!rdg_skip_seed_payload(tls, bodyLength))
			return FALSE;
	}
	else
	{
		if (!rdg_send_http_request(rdg, tls, method, "chunked"))
			return FALSE;
	}

	return TRUE;
}

static BOOL rdg_tunnel_connect(rdpRdg* rdg)
{
	BOOL status;
	wStream* s;
	rdg_send_handshake(rdg);

	while (rdg->state < RDG_CLIENT_STATE_OPENED)
	{
		status = FALSE;
		s = rdg_receive_packet(rdg);

		if (s)
		{
			status = rdg_process_packet(rdg, s);
			Stream_Free(s, TRUE);
		}

		if (!status)
		{
			rdg->context->rdp->transport->layer = TRANSPORT_LAYER_CLOSED;
			return FALSE;
		}
	}

	return TRUE;
}

BOOL rdg_connect(rdpRdg* rdg, int timeout, BOOL* rpcFallback)
{
	BOOL status;
	SOCKET outConnSocket = 0;
	char* peerAddress = NULL;
	assert(rdg != NULL);
	status =
	    rdg_establish_data_connection(rdg, rdg->tlsOut, "RDG_OUT_DATA", NULL, timeout, rpcFallback);

	if (status)
	{
		/* Establish IN connection with the same peer/server as OUT connection,
		 * even when server hostname resolves to different IP addresses.
		 */
		BIO_get_socket(rdg->tlsOut->underlying, &outConnSocket);
		peerAddress = freerdp_tcp_get_peer_address(outConnSocket);
		status = rdg_establish_data_connection(rdg, rdg->tlsIn, "RDG_IN_DATA", peerAddress, timeout,
		                                       NULL);
		free(peerAddress);
	}

	if (!status)
	{
		rdg->context->rdp->transport->layer = TRANSPORT_LAYER_CLOSED;
		return FALSE;
	}

	status = rdg_tunnel_connect(rdg);

	if (!status)
		return FALSE;

	return TRUE;
}

static int rdg_write_data_packet(rdpRdg* rdg, const BYTE* buf, int isize)
{
	int status;
	size_t s;
	wStream* sChunk;
	size_t size = (size_t)isize;
	size_t packetSize = size + 10;
	char chunkSize[11];

	if ((isize < 0) || (isize > UINT16_MAX))
		return -1;

	if (size < 1)
		return 0;

	sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIxz "\r\n", packetSize);
	sChunk = Stream_New(NULL, strnlen(chunkSize, sizeof(chunkSize)) + packetSize + 2);

	if (!sChunk)
		return -1;

	Stream_Write(sChunk, chunkSize, strnlen(chunkSize, sizeof(chunkSize)));
	Stream_Write_UINT16(sChunk, PKT_TYPE_DATA);      /* Type */
	Stream_Write_UINT16(sChunk, 0);                  /* Reserved */
	Stream_Write_UINT32(sChunk, (UINT32)packetSize); /* Packet length */
	Stream_Write_UINT16(sChunk, (UINT16)size);       /* Data size */
	Stream_Write(sChunk, buf, size);                 /* Data */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s > INT_MAX)
		return -1;

	status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);
	Stream_Free(sChunk, TRUE);

	if (status < 0)
		return -1;

	return (int)size;
}

static BOOL rdg_process_close_packet(rdpRdg* rdg)
{
	int status = -1;
	size_t s;
	wStream* sChunk;
	UINT32 packetSize = 12;
	char chunkSize[11];
	int chunkLen = sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIx32 "\r\n", packetSize);

	if (chunkLen < 0)
		return FALSE;

	sChunk = Stream_New(NULL, (size_t)chunkLen + packetSize + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, (size_t)chunkLen);
	Stream_Write_UINT16(sChunk, PKT_TYPE_CLOSE_CHANNEL_RESPONSE); /* Type */
	Stream_Write_UINT16(sChunk, 0);                               /* Reserved */
	Stream_Write_UINT32(sChunk, packetSize);                      /* Packet length */
	Stream_Write_UINT32(sChunk, 0);                               /* Status code */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s <= INT_MAX)
		status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);

	Stream_Free(sChunk, TRUE);
	return (status < 0 ? FALSE : TRUE);
}

static BOOL rdg_process_keep_alive_packet(rdpRdg* rdg)
{
	int status = -1;
	size_t s;
	wStream* sChunk;
	size_t packetSize = 8;
	char chunkSize[11];
	int chunkLen = sprintf_s(chunkSize, sizeof(chunkSize), "%" PRIxz "\r\n", packetSize);

	if ((chunkLen < 0) || (packetSize > UINT32_MAX))
		return FALSE;

	sChunk = Stream_New(NULL, (size_t)chunkLen + packetSize + 2);

	if (!sChunk)
		return FALSE;

	Stream_Write(sChunk, chunkSize, (size_t)chunkLen);
	Stream_Write_UINT16(sChunk, PKT_TYPE_KEEPALIVE); /* Type */
	Stream_Write_UINT16(sChunk, 0);                  /* Reserved */
	Stream_Write_UINT32(sChunk, (UINT32)packetSize); /* Packet length */
	Stream_Write(sChunk, "\r\n", 2);
	Stream_SealLength(sChunk);
	s = Stream_Length(sChunk);

	if (s <= INT_MAX)
		status = tls_write_all(rdg->tlsIn, Stream_Buffer(sChunk), (int)s);

	Stream_Free(sChunk, TRUE);
	return (status < 0 ? FALSE : TRUE);
}

static BOOL rdg_process_unknown_packet(rdpRdg* rdg, int type)
{
	WINPR_UNUSED(rdg);
	WINPR_UNUSED(type);
	WLog_WARN(TAG, "Unknown Control Packet received: %X", type);
	return TRUE;
}

static BOOL rdg_process_control_packet(rdpRdg* rdg, int type, size_t packetLength)
{
	wStream* s = NULL;
	size_t readCount = 0;
	int status;
	size_t payloadSize = packetLength - sizeof(RdgPacketHeader);

	if (packetLength < sizeof(RdgPacketHeader))
		return FALSE;

	assert(sizeof(RdgPacketHeader) < INT_MAX);

	if (payloadSize)
	{
		s = Stream_New(NULL, payloadSize);

		if (!s)
			return FALSE;

		while (readCount < payloadSize)
		{
			status =
			    BIO_read(rdg->tlsOut->bio, Stream_Pointer(s), (int)payloadSize - (int)readCount);

			if (status <= 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
				{
					Stream_Free(s, TRUE);
					return FALSE;
				}

				continue;
			}

			Stream_Seek(s, (size_t)status);
			readCount += (size_t)status;

			if (readCount > INT_MAX)
			{
				Stream_Free(s, TRUE);
				return FALSE;
			}
		}
	}

	switch (type)
	{
		case PKT_TYPE_CLOSE_CHANNEL:
			EnterCriticalSection(&rdg->writeSection);
			status = rdg_process_close_packet(rdg);
			LeaveCriticalSection(&rdg->writeSection);
			break;

		case PKT_TYPE_KEEPALIVE:
			EnterCriticalSection(&rdg->writeSection);
			status = rdg_process_keep_alive_packet(rdg);
			LeaveCriticalSection(&rdg->writeSection);
			break;

		default:
			status = rdg_process_unknown_packet(rdg, type);
			break;
	}

	Stream_Free(s, TRUE);
	return status;
}

static int rdg_read_data_packet(rdpRdg* rdg, BYTE* buffer, int size)
{
	RdgPacketHeader header;
	size_t readCount = 0;
	int readSize;
	int status;

	if (!rdg->packetRemainingCount)
	{
		assert(sizeof(RdgPacketHeader) < INT_MAX);

		while (readCount < sizeof(RdgPacketHeader))
		{
			status = BIO_read(rdg->tlsOut->bio, (BYTE*)(&header) + readCount,
			                  (int)sizeof(RdgPacketHeader) - (int)readCount);

			if (status <= 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
					return -1;

				if (!readCount)
					return 0;

				BIO_wait_read(rdg->tlsOut->bio, 50);
				continue;
			}

			readCount += (size_t)status;

			if (readCount > INT_MAX)
				return -1;
		}

		if (header.type != PKT_TYPE_DATA)
		{
			status = rdg_process_control_packet(rdg, header.type, header.packetLength);

			if (!status)
				return -1;

			return 0;
		}

		readCount = 0;

		while (readCount < 2)
		{
			status = BIO_read(rdg->tlsOut->bio, (BYTE*)(&rdg->packetRemainingCount) + readCount,
			                  2 - (int)readCount);

			if (status < 0)
			{
				if (!BIO_should_retry(rdg->tlsOut->bio))
					return -1;

				BIO_wait_read(rdg->tlsOut->bio, 50);
				continue;
			}

			readCount += (size_t)status;
		}
	}

	readSize = (rdg->packetRemainingCount < size ? rdg->packetRemainingCount : size);
	status = BIO_read(rdg->tlsOut->bio, buffer, readSize);

	if (status <= 0)
	{
		if (!BIO_should_retry(rdg->tlsOut->bio))
		{
			return -1;
		}

		return 0;
	}

	rdg->packetRemainingCount -= status;
	return status;
}

static int rdg_bio_write(BIO* bio, const char* buf, int num)
{
	int status;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	BIO_clear_flags(bio, BIO_FLAGS_WRITE);
	EnterCriticalSection(&rdg->writeSection);
	status = rdg_write_data_packet(rdg, (const BYTE*)buf, num);
	LeaveCriticalSection(&rdg->writeSection);

	if (status < 0)
	{
		BIO_clear_flags(bio, BIO_FLAGS_SHOULD_RETRY);
		return -1;
	}
	else if (status < num)
	{
		BIO_set_flags(bio, BIO_FLAGS_WRITE);
		WSASetLastError(WSAEWOULDBLOCK);
	}
	else
	{
		BIO_set_flags(bio, BIO_FLAGS_WRITE);
	}

	return status;
}

static int rdg_bio_read(BIO* bio, char* buf, int size)
{
	int status;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	status = rdg_read_data_packet(rdg, (BYTE*)buf, size);

	if (status < 0)
	{
		BIO_clear_retry_flags(bio);
		return -1;
	}
	else if (status == 0)
	{
		BIO_set_retry_read(bio);
		WSASetLastError(WSAEWOULDBLOCK);
		return -1;
	}
	else
	{
		BIO_set_flags(bio, BIO_FLAGS_READ);
	}

	return status;
}

static int rdg_bio_puts(BIO* bio, const char* str)
{
	WINPR_UNUSED(bio);
	WINPR_UNUSED(str);
	return -2;
}

static int rdg_bio_gets(BIO* bio, char* str, int size)
{
	WINPR_UNUSED(bio);
	WINPR_UNUSED(str);
	WINPR_UNUSED(size);
	return -2;
}

static long rdg_bio_ctrl(BIO* bio, int cmd, long arg1, void* arg2)
{
	long status = -1;
	rdpRdg* rdg = (rdpRdg*)BIO_get_data(bio);
	rdpTls* tlsOut = rdg->tlsOut;
	rdpTls* tlsIn = rdg->tlsIn;

	if (cmd == BIO_CTRL_FLUSH)
	{
		(void)BIO_flush(tlsOut->bio);
		(void)BIO_flush(tlsIn->bio);
		status = 1;
	}
	else if (cmd == BIO_C_SET_NONBLOCK)
	{
		status = 1;
	}
	else if (cmd == BIO_C_READ_BLOCKED)
	{
		BIO* bio = tlsOut->bio;
		status = BIO_read_blocked(bio);
	}
	else if (cmd == BIO_C_WRITE_BLOCKED)
	{
		BIO* bio = tlsIn->bio;
		status = BIO_write_blocked(bio);
	}
	else if (cmd == BIO_C_WAIT_READ)
	{
		int timeout = (int)arg1;
		BIO* bio = tlsOut->bio;

		if (BIO_read_blocked(bio))
			return BIO_wait_read(bio, timeout);
		else if (BIO_write_blocked(bio))
			return BIO_wait_write(bio, timeout);
		else
			status = 1;
	}
	else if (cmd == BIO_C_WAIT_WRITE)
	{
		int timeout = (int)arg1;
		BIO* bio = tlsIn->bio;

		if (BIO_write_blocked(bio))
			status = BIO_wait_write(bio, timeout);
		else if (BIO_read_blocked(bio))
			status = BIO_wait_read(bio, timeout);
		else
			status = 1;
	}
	else if (cmd == BIO_C_GET_EVENT || cmd == BIO_C_GET_FD)
	{
		/*
		 * A note about BIO_C_GET_FD:
		 * Even if two FDs are part of RDG, only one FD can be returned here.
		 *
		 * In FreeRDP, BIO FDs are only used for polling, so it is safe to use the outgoing FD only
		 *
		 * See issue #3602
		 */
		status = BIO_ctrl(tlsOut->bio, cmd, arg1, arg2);
	}

	return status;
}

static int rdg_bio_new(BIO* bio)
{
	BIO_set_init(bio, 1);
	BIO_set_flags(bio, BIO_FLAGS_SHOULD_RETRY);
	return 1;
}

static int rdg_bio_free(BIO* bio)
{
	WINPR_UNUSED(bio);
	return 1;
}

static BIO_METHOD* BIO_s_rdg(void)
{
	static BIO_METHOD* bio_methods = NULL;

	if (bio_methods == NULL)
	{
		if (!(bio_methods = BIO_meth_new(BIO_TYPE_TSG, "RDGateway")))
			return NULL;

		BIO_meth_set_write(bio_methods, rdg_bio_write);
		BIO_meth_set_read(bio_methods, rdg_bio_read);
		BIO_meth_set_puts(bio_methods, rdg_bio_puts);
		BIO_meth_set_gets(bio_methods, rdg_bio_gets);
		BIO_meth_set_ctrl(bio_methods, rdg_bio_ctrl);
		BIO_meth_set_create(bio_methods, rdg_bio_new);
		BIO_meth_set_destroy(bio_methods, rdg_bio_free);
	}

	return bio_methods;
}

rdpRdg* rdg_new(rdpContext* context)
{
	rdpRdg* rdg;
	RPC_CSTR stringUuid;
	char bracedUuid[40];
	RPC_STATUS rpcStatus;

	if (!context)
		return NULL;

	rdg = (rdpRdg*)calloc(1, sizeof(rdpRdg));

	if (rdg)
	{
		rdg->state = RDG_CLIENT_STATE_INITIAL;
		rdg->context = context;
		rdg->settings = rdg->context->settings;
		rdg->extAuth = HTTP_EXTENDED_AUTH_NONE;

		if (rdg->settings->GatewayAccessToken)
			rdg->extAuth = HTTP_EXTENDED_AUTH_PAA;

		UuidCreate(&rdg->guid);
		rpcStatus = UuidToStringA(&rdg->guid, &stringUuid);

		if (rpcStatus == RPC_S_OUT_OF_MEMORY)
			goto rdg_alloc_error;

		sprintf_s(bracedUuid, sizeof(bracedUuid), "{%s}", stringUuid);
		RpcStringFreeA(&stringUuid);
		rdg->tlsOut = tls_new(rdg->settings);

		if (!rdg->tlsOut)
			goto rdg_alloc_error;

		rdg->tlsIn = tls_new(rdg->settings);

		if (!rdg->tlsIn)
			goto rdg_alloc_error;

		rdg->http = http_context_new();

		if (!rdg->http)
			goto rdg_alloc_error;

		if (!http_context_set_uri(rdg->http, "/remoteDesktopGateway/") ||
		    !http_context_set_accept(rdg->http, "*/*") ||
		    !http_context_set_cache_control(rdg->http, "no-cache") ||
		    !http_context_set_pragma(rdg->http, "no-cache") ||
		    !http_context_set_connection(rdg->http, "Keep-Alive") ||
		    !http_context_set_user_agent(rdg->http, "MS-RDGateway/1.0") ||
		    !http_context_set_host(rdg->http, rdg->settings->GatewayHostname) ||
		    !http_context_set_rdg_connection_id(rdg->http, bracedUuid))
		{
			goto rdg_alloc_error;
		}

		if (rdg->extAuth != HTTP_EXTENDED_AUTH_NONE)
		{
			switch (rdg->extAuth)
			{
				case HTTP_EXTENDED_AUTH_PAA:
					if (!http_context_set_rdg_auth_scheme(rdg->http, "PAA"))
						goto rdg_alloc_error;

					break;

				default:
					WLog_DBG(TAG, "RDG extended authentication method %d not supported",
					         rdg->extAuth);
			}
		}

		rdg->frontBio = BIO_new(BIO_s_rdg());

		if (!rdg->frontBio)
			goto rdg_alloc_error;

		BIO_set_data(rdg->frontBio, rdg);
		InitializeCriticalSection(&rdg->writeSection);
	}

	return rdg;
rdg_alloc_error:
	rdg_free(rdg);
	return NULL;
}

void rdg_free(rdpRdg* rdg)
{
	if (!rdg)
		return;

	tls_free(rdg->tlsOut);
	tls_free(rdg->tlsIn);
	http_context_free(rdg->http);
	ntlm_free(rdg->ntlm);

	if (!rdg->attached)
		BIO_free_all(rdg->frontBio);

	DeleteCriticalSection(&rdg->writeSection);
	free(rdg);
}

BIO* rdg_get_front_bio_and_take_ownership(rdpRdg* rdg)
{
	if (!rdg)
		return NULL;

	rdg->attached = TRUE;
	return rdg->frontBio;
}