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FreeRDP/libfreerdp/common/assistance.c

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/**
* FreeRDP: A Remote Desktop Protocol Implementation
* Remote Assistance
*
* Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.com>
*
* 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 <winpr/crt.h>
#include <winpr/print.h>
#include <winpr/windows.h>
#include <openssl/ssl.h>
#include <openssl/md5.h>
#include <openssl/rc4.h>
#include <openssl/sha.h>
#include <openssl/evp.h>
#include <openssl/aes.h>
#include <openssl/rand.h>
#include <openssl/engine.h>
#include <freerdp/utils/debug.h>
#include <freerdp/client/file.h>
#include <freerdp/client/cmdline.h>
#include <freerdp/assistance.h>
/**
* Password encryption in establishing a remote assistance session of type 1:
* http://blogs.msdn.com/b/openspecification/archive/2011/10/31/password-encryption-in-establishing-a-remote-assistance-session-of-type-1.aspx
*
* Creation of PassStub for the Remote Assistance Ticket:
* http://social.msdn.microsoft.com/Forums/en-US/6316c3f4-ea09-4343-a4a1-9cca46d70d28/creation-of-passstub-for-the-remote-assistance-ticket?forum=os_windowsprotocols
*/
/**
* CryptDeriveKey Function:
* http://msdn.microsoft.com/en-us/library/windows/desktop/aa379916/
*
* Let n be the required derived key length, in bytes.
* The derived key is the first n bytes of the hash value after the hash computation
* has been completed by CryptDeriveKey. If the hash is not a member of the SHA-2
* family and the required key is for either 3DES or AES, the key is derived as follows:
*
* Form a 64-byte buffer by repeating the constant 0x36 64 times.
* Let k be the length of the hash value that is represented by the input parameter hBaseData.
* Set the first k bytes of the buffer to the result of an XOR operation of the first k bytes
* of the buffer with the hash value that is represented by the input parameter hBaseData.
*
* Form a 64-byte buffer by repeating the constant 0x5C 64 times.
* Set the first k bytes of the buffer to the result of an XOR operation of the first k bytes
* of the buffer with the hash value that is represented by the input parameter hBaseData.
*
* Hash the result of step 1 by using the same hash algorithm as that used to compute the hash
* value that is represented by the hBaseData parameter.
*
* Hash the result of step 2 by using the same hash algorithm as that used to compute the hash
* value that is represented by the hBaseData parameter.
*
* Concatenate the result of step 3 with the result of step 4.
* Use the first n bytes of the result of step 5 as the derived key.
*/
int freerdp_assistance_crypt_derive_key_sha1(BYTE* hash, int hashLength, BYTE* key, int keyLength)
{
int i;
BYTE* buffer;
BYTE pad1[64];
BYTE pad2[64];
SHA_CTX hashCtx;
memset(pad1, 0x36, 64);
memset(pad2, 0x5C, 64);
for (i = 0; i < hashLength; i++)
{
pad1[i] ^= hash[i];
pad2[i] ^= hash[i];
}
buffer = (BYTE*) calloc(1, hashLength * 2);
if (!buffer)
return -1;
SHA1_Init(&hashCtx);
SHA1_Update(&hashCtx, pad1, 64);
SHA1_Final((void*) buffer, &hashCtx);
SHA1_Init(&hashCtx);
SHA1_Update(&hashCtx, pad2, 64);
SHA1_Final((void*) &buffer[hashLength], &hashCtx);
CopyMemory(key, buffer, keyLength);
free(buffer);
return 1;
}
int freerdp_assistance_parse_address_list(rdpAssistanceFile* file, char* list)
{
int i;
char* p;
char* q;
char* str;
int count;
int length;
char** tokens;
count = 1;
str = _strdup(list);
if (!str)
return -1;
length = strlen(str);
for (i = 0; i < length; i++)
{
if (str[i] == ';')
count++;
}
tokens = (char**) malloc(sizeof(char*) * count);
count = 0;
tokens[count++] = str;
for (i = 0; i < length; i++)
{
if (str[i] == ';')
{
str[i] = '\0';
tokens[count++] = &str[i + 1];
}
}
for (i = 0; i < count; i++)
{
length = strlen(tokens[i]);
if (length > 8)
{
if (strncmp(tokens[i], "169.254.", 8) == 0)
continue;
}
p = tokens[i];
q = strchr(p, ':');
if (!q)
return -1;
q[0] = '\0';
q++;
file->MachineAddress = _strdup(p);
file->MachinePort = (UINT32) atoi(q);
break;
}
return 1;
}
int freerdp_assistance_parse_connection_string1(rdpAssistanceFile* file)
{
int i;
char* str;
int count;
int length;
char* tokens[8];
/**
* <ProtocolVersion>,<protocolType>,<machineAddressList>,<assistantAccountPwd>,
* <RASessionID>,<RASessionName>,<RASessionPwd>,<protocolSpecificParms>
*/
count = 1;
str = _strdup(file->RCTicket);
if (!str)
return -1;
length = strlen(str);
for (i = 0; i < length; i++)
{
if (str[i] == ',')
count++;
}
if (count != 8)
return -1;
count = 0;
tokens[count++] = str;
for (i = 0; i < length; i++)
{
if (str[i] == ',')
{
str[i] = '\0';
tokens[count++] = &str[i + 1];
}
}
if (strcmp(tokens[0], "65538") != 0)
return -1;
if (strcmp(tokens[1], "1") != 0)
return -1;
if (strcmp(tokens[3], "*") != 0)
return -1;
if (strcmp(tokens[5], "*") != 0)
return -1;
if (strcmp(tokens[6], "*") != 0)
return -1;
file->RASessionId = _strdup(tokens[4]);
if (!file->RASessionId)
return -1;
file->RASpecificParams = _strdup(tokens[7]);
if (!file->RASpecificParams)
return -1;
freerdp_assistance_parse_address_list(file, tokens[2]);
free(str);
return 1;
}
/**
* Decrypted Connection String 2:
*
* <E>
* <A KH="BNRjdu97DyczQSRuMRrDWoue+HA=" ID="+ULZ6ifjoCa6cGPMLQiGHRPwkg6VyJqGwxMnO6GcelwUh9a6/FBq3It5ADSndmLL"/>
* <C>
* <T ID="1" SID="0">
* <L P="49228" N="fe80::1032:53d9:5a01:909b%3"/>
* <L P="49229" N="fe80::3d8f:9b2d:6b4e:6aa%6"/>
* <L P="49230" N="192.168.1.200"/>
* <L P="49231" N="169.254.6.170"/>
* </T>
* </C>
* </E>
*/
int freerdp_assistance_parse_connection_string2(rdpAssistanceFile* file)
{
char* p;
char* q;
char* str;
size_t length;
str = _strdup(file->ConnectionString2);
if (!str)
return -1;
p = strstr(str, "<E>");
if (!p)
return -1;
p = strstr(str, "<C>");
if (!p)
return -1;
/* Auth String Node (<A>) */
p = strstr(str, "<A");
if (!p)
return -1;
p = strstr(p, "KH=\"");
if (p)
{
p += sizeof("KH=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
free(file->RASpecificParams);
file->RASpecificParams = (char*) malloc(length + 1);
if (!file->RASpecificParams)
return -1;
CopyMemory(file->RASpecificParams, p, length);
file->RASpecificParams[length] = '\0';
p += length;
}
p = strstr(p, "ID=\"");
if (p)
{
p += sizeof("ID=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
free(file->RASessionId);
file->RASessionId = (char*) malloc(length + 1);
if (!file->RASessionId)
return -1;
CopyMemory(file->RASessionId, p, length);
file->RASessionId[length] = '\0';
p += length;
}
free(str);
return 1;
}
char* freerdp_assistance_construct_expert_blob(const char* name, const char* pass)
{
int size;
int nameLength;
int passLength;
char* ExpertBlob = NULL;
if (!name || !pass)
return NULL;
nameLength = strlen(name) + strlen("NAME=");
passLength = strlen(pass) + strlen("PASS=");
size = nameLength + passLength + 64;
ExpertBlob = (char*) calloc(1, size);
if (!ExpertBlob)
return NULL;
sprintf_s(ExpertBlob, size, "%d;NAME=%s%d;PASS=%s",
nameLength, name, passLength, pass);
return ExpertBlob;
}
BYTE* freerdp_assistance_encrypt_pass_stub(const char* password, const char* passStub, int* pEncryptedSize)
{
int status;
MD5_CTX md5Ctx;
int cbPasswordW;
int cbPassStubW;
int EncryptedSize;
BYTE PasswordHash[16];
EVP_CIPHER_CTX rc4Ctx;
BYTE *pbIn, *pbOut;
int cbOut, cbIn, cbFinal;
WCHAR* PasswordW = NULL;
WCHAR* PassStubW = NULL;
status = ConvertToUnicode(CP_UTF8, 0, password, -1, &PasswordW, 0);
if (status <= 0)
return NULL;
cbPasswordW = (status - 1) * 2;
MD5_Init(&md5Ctx);
MD5_Update(&md5Ctx, PasswordW, cbPasswordW);
MD5_Final((void*) PasswordHash, &md5Ctx);
status = ConvertToUnicode(CP_UTF8, 0, passStub, -1, &PassStubW, 0);
if (status <= 0)
return NULL;
cbPassStubW = (status - 1) * 2;
EncryptedSize = cbPassStubW + 4;
pbIn = (BYTE*) calloc(1, EncryptedSize);
pbOut = (BYTE*) calloc(1, EncryptedSize);
if (!pbIn)
return NULL;
if (!EncryptedSize)
return NULL;
*((UINT32*) pbIn) = cbPassStubW;
CopyMemory(&pbIn[4], PassStubW, cbPassStubW);
EVP_CIPHER_CTX_init(&rc4Ctx);
status = EVP_EncryptInit_ex(&rc4Ctx, EVP_rc4(), NULL, NULL, NULL);
if (!status)
{
DEBUG_WARN( "EVP_CipherInit_ex failure\n");
return NULL;
}
status = EVP_EncryptInit_ex(&rc4Ctx, NULL, NULL, PasswordHash, NULL);
if (!status)
{
DEBUG_WARN( "EVP_CipherInit_ex failure\n");
return NULL;
}
cbOut = cbFinal = 0;
cbIn = EncryptedSize;
status = EVP_EncryptUpdate(&rc4Ctx, pbOut, &cbOut, pbIn, cbIn);
if (!status)
{
DEBUG_WARN( "EVP_CipherUpdate failure\n");
return NULL;
}
status = EVP_EncryptFinal_ex(&rc4Ctx, pbOut + cbOut, &cbFinal);
if (!status)
{
DEBUG_WARN( "EVP_CipherFinal_ex failure\n");
return NULL;
}
EVP_CIPHER_CTX_cleanup(&rc4Ctx);
free(pbIn);
free(PasswordW);
free(PassStubW);
*pEncryptedSize = EncryptedSize;
return pbOut;
}
int freerdp_assistance_decrypt2(rdpAssistanceFile* file, const char* password)
{
int status;
SHA_CTX shaCtx;
int cbPasswordW;
int cchOutW = 0;
WCHAR* pbOutW = NULL;
EVP_CIPHER_CTX aesDec;
WCHAR* PasswordW = NULL;
BYTE *pbIn, *pbOut;
int cbOut, cbIn, cbFinal;
BYTE DerivedKey[AES_BLOCK_SIZE];
BYTE InitializationVector[AES_BLOCK_SIZE];
BYTE PasswordHash[SHA_DIGEST_LENGTH];
status = ConvertToUnicode(CP_UTF8, 0, password, -1, &PasswordW, 0);
if (status <= 0)
return -1;
cbPasswordW = (status - 1) * 2;
SHA1_Init(&shaCtx);
SHA1_Update(&shaCtx, PasswordW, cbPasswordW);
SHA1_Final((void*) PasswordHash, &shaCtx);
status = freerdp_assistance_crypt_derive_key_sha1(PasswordHash, sizeof(PasswordHash),
DerivedKey, sizeof(DerivedKey));
if (status < 0)
return -1;
ZeroMemory(InitializationVector, sizeof(InitializationVector));
EVP_CIPHER_CTX_init(&aesDec);
status = EVP_DecryptInit_ex(&aesDec, EVP_aes_128_cbc(), NULL, NULL, NULL);
if (status != 1)
return -1;
EVP_CIPHER_CTX_set_key_length(&aesDec, (128 / 8));
EVP_CIPHER_CTX_set_padding(&aesDec, 0);
status = EVP_DecryptInit_ex(&aesDec, EVP_aes_128_cbc(), NULL, DerivedKey, InitializationVector);
if (status != 1)
return -1;
cbOut = cbFinal = 0;
cbIn = file->EncryptedLHTicketLength;
pbIn = (BYTE*) file->EncryptedLHTicket;
pbOut = (BYTE*) calloc(1, cbIn + AES_BLOCK_SIZE + 2);
if (!pbOut)
return -1;
status = EVP_DecryptUpdate(&aesDec, pbOut, &cbOut, pbIn, cbIn);
if (status != 1)
return -1;
status = EVP_DecryptFinal_ex(&aesDec, pbOut + cbOut, &cbFinal);
if (status != 1)
{
DEBUG_WARN( "EVP_DecryptFinal_ex failure\n");
return -1;
}
EVP_CIPHER_CTX_cleanup(&aesDec);
cbOut += cbFinal;
cbFinal = 0;
pbOutW = (WCHAR*) pbOut;
cchOutW = cbOut / 2;
file->ConnectionString2 = NULL;
status = ConvertFromUnicode(CP_UTF8, 0, pbOutW, cchOutW, &file->ConnectionString2, 0, NULL, NULL);
if (status <= 0)
return -1;
free(PasswordW);
free(pbOut);
status = freerdp_assistance_parse_connection_string2(file);
DEBUG_MSG("freerdp_assistance_parse_connection_string2: %d\n", status);
return 1;
}
int freerdp_assistance_decrypt(rdpAssistanceFile* file, const char* password)
{
int status = 1;
file->EncryptedPassStub = freerdp_assistance_encrypt_pass_stub(password,
file->PassStub, &file->EncryptedPassStubLength);
if (!file->EncryptedPassStub)
return -1;
if (file->Type > 1)
{
status = freerdp_assistance_decrypt2(file, password);
}
return status;
}
BYTE* freerdp_assistance_hex_string_to_bin(const char* str, int* size)
{
char c;
int length;
BYTE* buffer;
int i, ln, hn;
length = strlen(str);
if ((length % 2) != 0)
return NULL;
length /= 2;
*size = length;
buffer = (BYTE*) malloc(length);
if (!buffer)
return NULL;
for (i = 0; i < length; i++)
{
hn = ln = 0;
c = str[(i * 2) + 0];
if ((c >= '0') && (c <= '9'))
hn = c - '0';
else if ((c >= 'a') && (c <= 'f'))
hn = (c - 'a') + 10;
else if ((c >= 'A') && (c <= 'F'))
hn = (c - 'A') + 10;
c = str[(i * 2) + 1];
if ((c >= '0') && (c <= '9'))
ln = c - '0';
else if ((c >= 'a') && (c <= 'f'))
ln = (c - 'a') + 10;
else if ((c >= 'A') && (c <= 'F'))
ln = (c - 'A') + 10;
buffer[i] = (hn << 4) | ln;
}
return buffer;
}
char* freerdp_assistance_bin_to_hex_string(const BYTE* data, int size)
{
int i;
char* p;
int ln, hn;
char bin2hex[] = "0123456789ABCDEF";
p = (char*) malloc((size + 1) * 2);
for (i = 0; i < size; i++)
{
ln = data[i] & 0xF;
hn = (data[i] >> 4) & 0xF;
p[i * 2] = bin2hex[hn];
p[(i * 2) + 1] = bin2hex[ln];
}
p[size * 2] = '\0';
return p;
}
int freerdp_assistance_parse_file_buffer(rdpAssistanceFile* file, const char* buffer, size_t size)
{
char* p;
char* q;
char* r;
int value;
int status;
size_t length;
p = strstr(buffer, "UPLOADINFO");
if (!p)
return -1;
p = strstr(p + sizeof("UPLOADINFO") - 1, "TYPE=\"");
if (!p)
return -1;
p = strstr(buffer, "UPLOADDATA");
if (!p)
return -1;
/* Parse USERNAME */
p = strstr(buffer, "USERNAME=\"");
if (p)
{
p += sizeof("USERNAME=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
file->Username = (char*) malloc(length + 1);
if (!file->Username)
return -1;
CopyMemory(file->Username, p, length);
file->Username[length] = '\0';
}
/* Parse LHTICKET */
p = strstr(buffer, "LHTICKET=\"");
if (p)
{
p += sizeof("LHTICKET=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
file->LHTicket = (char*) malloc(length + 1);
if (!file->LHTicket)
return -1;
CopyMemory(file->LHTicket, p, length);
file->LHTicket[length] = '\0';
}
/* Parse RCTICKET */
p = strstr(buffer, "RCTICKET=\"");
if (p)
{
p += sizeof("RCTICKET=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
file->RCTicket = (char*) malloc(length + 1);
if (!file->RCTicket)
return -1;
CopyMemory(file->RCTicket, p, length);
file->RCTicket[length] = '\0';
}
/* Parse RCTICKETENCRYPTED */
p = strstr(buffer, "RCTICKETENCRYPTED=\"");
if (p)
{
p += sizeof("RCTICKETENCRYPTED=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
if ((length == 1) && (p[0] == '1'))
file->RCTicketEncrypted = TRUE;
}
/* Parse PassStub */
p = strstr(buffer, "PassStub=\"");
if (p)
{
p += sizeof("PassStub=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
file->PassStub = (char*) malloc(length + 1);
if (!file->PassStub)
return -1;
CopyMemory(file->PassStub, p, length);
file->PassStub[length] = '\0';
}
/* Parse DtStart */
p = strstr(buffer, "DtStart=\"");
if (p)
{
p += sizeof("DtStart=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
r = (char*) malloc(length + 1);
if (!r)
return -1;
CopyMemory(r, p, length);
r[length] = '\0';
value = atoi(r);
free(r);
if (value < 0)
return -1;
file->DtStart = (UINT32) value;
}
/* Parse DtLength */
p = strstr(buffer, "DtLength=\"");
if (p)
{
p += sizeof("DtLength=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
r = (char*) malloc(length + 1);
if (!r)
return -1;
CopyMemory(r, p, length);
r[length] = '\0';
value = atoi(r);
free(r);
if (value < 0)
return -1;
file->DtLength = (UINT32) value;
}
/* Parse L (LowSpeed) */
p = strstr(buffer, " L=\"");
if (p)
{
p += sizeof(" L=\"") - 1;
q = strchr(p, '"');
if (!q)
return -1;
length = q - p;
if ((length == 1) && (p[0] == '1'))
file->LowSpeed = TRUE;
}
file->Type = (file->LHTicket) ? 2 : 1;
if (file->LHTicket)
{
file->EncryptedLHTicket = freerdp_assistance_hex_string_to_bin(file->LHTicket,
&file->EncryptedLHTicketLength);
}
status = freerdp_assistance_parse_connection_string1(file);
if (status < 0)
{
DEBUG_WARN( "freerdp_assistance_parse_connection_string1 failure: %d\n", status);
return -1;
}
return 1;
}
int freerdp_assistance_parse_file(rdpAssistanceFile* file, const char* name)
{
int status;
BYTE* buffer;
FILE* fp = NULL;
size_t readSize;
long int fileSize;
fp = fopen(name, "r");
if (!fp)
return -1;
fseek(fp, 0, SEEK_END);
fileSize = ftell(fp);
fseek(fp, 0, SEEK_SET);
if (fileSize < 1)
{
fclose(fp);
return -1;
}
buffer = (BYTE*) malloc(fileSize + 2);
readSize = fread(buffer, fileSize, 1, fp);
if (!readSize)
{
if (!ferror(fp))
readSize = fileSize;
}
fclose(fp);
if (readSize < 1)
{
free(buffer);
buffer = NULL;
return -1;
}
buffer[fileSize] = '\0';
buffer[fileSize + 1] = '\0';
status = freerdp_assistance_parse_file_buffer(file, (char*) buffer, fileSize);
free(buffer);
return status;
}
int freerdp_client_populate_settings_from_assistance_file(rdpAssistanceFile* file, rdpSettings* settings)
{
freerdp_set_param_bool(settings, FreeRDP_RemoteAssistanceMode, TRUE);
if (!file->RASessionId)
return -1;
freerdp_set_param_string(settings, FreeRDP_RemoteAssistanceSessionId, file->RASessionId);
if (file->RCTicket)
freerdp_set_param_string(settings, FreeRDP_RemoteAssistanceRCTicket, file->RCTicket);
if (file->PassStub)
freerdp_set_param_string(settings, FreeRDP_RemoteAssistancePassStub, file->PassStub);
if (!file->MachineAddress)
return -1;
freerdp_set_param_string(settings, FreeRDP_ServerHostname, file->MachineAddress);
freerdp_set_param_uint32(settings, FreeRDP_ServerPort, file->MachinePort);
return 1;
}
rdpAssistanceFile* freerdp_assistance_file_new()
{
rdpAssistanceFile* file;
file = (rdpAssistanceFile*) calloc(1, sizeof(rdpAssistanceFile));
if (file)
{
}
return file;
}
void freerdp_assistance_file_free(rdpAssistanceFile* file)
{
if (!file)
return;
free(file->Username);
free(file->LHTicket);
free(file->RCTicket);
free(file->PassStub);
free(file->ConnectionString1);
free(file->ConnectionString2);
free(file->EncryptedLHTicket);
free(file->RASessionId);
free(file->RASpecificParams);
free(file->MachineAddress);
free(file->EncryptedPassStub);
free(file);
}
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