/** * FreeRDP: A Remote Desktop Protocol Implementation * Remote Assistance * * Copyright 2014 Marc-Andre Moreau * * 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 #include #include #include #include #include #include #include #include #include #define TAG FREERDP_TAG("common") struct rdp_assistance_file { UINT32 Type; char* Username; char* LHTicket; char* RCTicket; char* PassStub; UINT32 DtStart; UINT32 DtLength; BOOL LowSpeed; BOOL RCTicketEncrypted; char* ConnectionString1; char* ConnectionString2; BYTE* EncryptedPassStub; size_t EncryptedPassStubLength; BYTE* EncryptedLHTicket; size_t EncryptedLHTicketLength; UINT32 MachineCount; char** MachineAddresses; UINT32* MachinePorts; char* RASessionId; char* RASpecificParams; char* filename; char* password; }; /** * 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. */ static BOOL freerdp_assistance_crypt_derive_key_sha1(BYTE* hash, size_t hashLength, BYTE* key, size_t keyLength) { BOOL rc = FALSE; size_t i; BYTE* buffer; BYTE pad1[64]; BYTE pad2[64]; 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(hashLength, 2); if (!buffer) goto fail; if (!winpr_Digest(WINPR_MD_SHA1, pad1, 64, buffer, hashLength)) goto fail; if (!winpr_Digest(WINPR_MD_SHA1, pad2, 64, &buffer[hashLength], hashLength)) goto fail; CopyMemory(key, buffer, keyLength); rc = TRUE; fail: free(buffer); return rc; } static BOOL reallocate(rdpAssistanceFile* file, const char* host, UINT32 port) { void* tmp1, *tmp2; file->MachineCount++; tmp1 = realloc(file->MachinePorts, sizeof(UINT32) * file->MachineCount); tmp2 = realloc(file->MachineAddresses, sizeof(char*) * file->MachineCount); if (!tmp1 || !tmp2) { free(tmp1); free(tmp2); return FALSE; } file->MachinePorts = tmp1; file->MachineAddresses = tmp2; file->MachinePorts[file->MachineCount - 1] = port; file->MachineAddresses[file->MachineCount - 1] = _strdup(host); return TRUE; } static BOOL append_address(rdpAssistanceFile* file, const char* host, const char* port) { unsigned long p; if (!file || !host || !port) return FALSE; errno = 0; p = strtoul(port, NULL, 0); if ((errno != 0) || (p == 0) || (p > UINT16_MAX)) return FALSE; return reallocate(file, host, p); } static BOOL freerdp_assistance_parse_address_list(rdpAssistanceFile* file, const char* list) { BOOL rc = FALSE; char* p; char* str; if (!file || !list) return FALSE; str = _strdup(list); if (!str) return FALSE; p = str; while ((p = strchr(p, ';')) != NULL) { char* q = strchr(p, ':'); if (!q) goto out; *q = '\0'; q++; if (!append_address(file, p, q)) goto out; p = q; } rc = TRUE; out: free(str); return TRUE; } static BOOL freerdp_assistance_parse_connection_string1(rdpAssistanceFile* file) { size_t i; char* str; int count; size_t length; char* tokens[8]; BOOL rc = FALSE; if (!file || !file->RCTicket) return FALSE; /** * ,,,, * ,,, */ count = 1; str = _strdup(file->RCTicket); if (!str) goto error; length = strlen(str); for (i = 0; i < length; i++) { if (str[i] == ',') count++; } if (count != 8) goto error; 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) goto error; if (strcmp(tokens[1], "1") != 0) goto error; if (strcmp(tokens[3], "*") != 0) goto error; if (strcmp(tokens[5], "*") != 0) goto error; if (strcmp(tokens[6], "*") != 0) goto error; file->RASessionId = _strdup(tokens[4]); if (!file->RASessionId) goto error; file->RASpecificParams = _strdup(tokens[7]); if (!file->RASpecificParams) goto error; if (!freerdp_assistance_parse_address_list(file, tokens[2])) goto error; rc = TRUE; error: free(str); return rc; } /** * Decrypted Connection String 2: * * * * * * * * * * * * */ static BOOL freerdp_assistance_parse_connection_string2(rdpAssistanceFile* file) { char* str; char* tag; char* end; char* p; BOOL rc = FALSE; if (!file || !file->ConnectionString2) return FALSE; str = file->ConnectionString2; if (!strstr(str, "")) return FALSE; if (!strstr(str, "")) return FALSE; str = _strdup(file->ConnectionString2); if (!str) goto out_fail; if (!(tag = strstr(str, ") */ end = strstr(tag, "/>"); if (!end) goto out_fail; *end = '\0'; p = strstr(tag, "KH=\""); if (p) { char* q; size_t length; p += sizeof("KH=\"") - 1; q = strchr(p, '"'); if (!q) goto out_fail; length = q - p; free(file->RASpecificParams); file->RASpecificParams = (char*) malloc(length + 1); if (!file->RASpecificParams) goto out_fail; CopyMemory(file->RASpecificParams, p, length); file->RASpecificParams[length] = '\0'; } p = strstr(tag, "ID=\""); if (p) { char* q; size_t length; p += sizeof("ID=\"") - 1; q = strchr(p, '"'); if (!q) goto out_fail; length = q - p; free(file->RASessionId); file->RASessionId = (char*) malloc(length + 1); if (!file->RASessionId) goto out_fail; CopyMemory(file->RASessionId, p, length); file->RASessionId[length] = '\0'; } *end = '/'; /* Parse 8) { if (!append_address(file, p, port)) goto out_fail; } p = strstr(q, " UINT32_MAX)) goto fail; *((UINT32*) pbIn) = (UINT32)cbPassStubW; CopyMemory(&pbIn[4], PassStubW, cbPassStubW); rc4Ctx = winpr_Cipher_New(WINPR_CIPHER_ARC4_128, WINPR_ENCRYPT, PasswordHash, NULL); if (!rc4Ctx) { WLog_ERR(TAG, "EVP_CipherInit_ex failure"); goto fail; } cbOut = cbFinal = 0; cbIn = EncryptedSize; rc = winpr_Cipher_Update(rc4Ctx, pbIn, cbIn, pbOut, &cbOut); if (!rc) { WLog_ERR(TAG, "EVP_CipherUpdate failure"); goto fail; } if (!winpr_Cipher_Final(rc4Ctx, pbOut + cbOut, &cbFinal)) { WLog_ERR(TAG, "EVP_CipherFinal_ex failure"); goto fail; } winpr_Cipher_Free(rc4Ctx); free(pbIn); free(PasswordW); free(PassStubW); *pEncryptedSize = EncryptedSize; return pbOut; fail: winpr_Cipher_Free(rc4Ctx); free(PasswordW); free(PassStubW); free(pbIn); free(pbOut); return NULL; } static BOOL freerdp_assistance_decrypt2(rdpAssistanceFile* file, const char* password) { BOOL rc = FALSE; int status = 0; size_t cbPasswordW; int cchOutW = 0; WCHAR* pbOutW = NULL; WINPR_CIPHER_CTX* aesDec = NULL; WCHAR* PasswordW = NULL; BYTE* pbIn = NULL; BYTE* pbOut = NULL; size_t cbOut, cbIn, cbFinal; BYTE DerivedKey[WINPR_AES_BLOCK_SIZE]; BYTE InitializationVector[WINPR_AES_BLOCK_SIZE]; BYTE PasswordHash[WINPR_SHA1_DIGEST_LENGTH]; if (!file || !password) return FALSE; status = ConvertToUnicode(CP_UTF8, 0, password, -1, &PasswordW, 0); if (status <= 0) return FALSE; cbPasswordW = (size_t)(status - 1) * 2UL; if (!winpr_Digest(WINPR_MD_SHA1, (BYTE*)PasswordW, cbPasswordW, PasswordHash, sizeof(PasswordHash))) goto fail; if (!freerdp_assistance_crypt_derive_key_sha1(PasswordHash, sizeof(PasswordHash), DerivedKey, sizeof(DerivedKey))) goto fail; ZeroMemory(InitializationVector, sizeof(InitializationVector)); aesDec = winpr_Cipher_New(WINPR_CIPHER_AES_128_CBC, WINPR_DECRYPT, DerivedKey, InitializationVector); if (!aesDec) goto fail; cbOut = cbFinal = 0; cbIn = (size_t)file->EncryptedLHTicketLength; pbIn = (BYTE*) file->EncryptedLHTicket; pbOut = (BYTE*) calloc(1, cbIn + WINPR_AES_BLOCK_SIZE + 2); if (!pbOut) goto fail; if (!winpr_Cipher_Update(aesDec, pbIn, cbIn, pbOut, &cbOut)) goto fail; if (!winpr_Cipher_Final(aesDec, pbOut + cbOut, &cbFinal)) { WLog_ERR(TAG, "EVP_DecryptFinal_ex failure"); goto fail; } cbOut += cbFinal; cbFinal = 0; pbOutW = (WCHAR*) pbOut; if (cbOut > INT_MAX / 2) goto fail; cchOutW = (int)cbOut / 2; file->ConnectionString2 = NULL; status = ConvertFromUnicode(CP_UTF8, 0, pbOutW, cchOutW, &file->ConnectionString2, 0, NULL, NULL); if (status <= 0) goto fail; if (!freerdp_assistance_parse_connection_string2(file)) goto fail; rc = TRUE; fail: winpr_Cipher_Free(aesDec); free(PasswordW); free(pbOut); WLog_DBG(TAG, "freerdp_assistance_parse_connection_string2: %d", status); return rc; } BYTE* freerdp_assistance_hex_string_to_bin(const char* str, size_t* size) { size_t length; BYTE* buffer; size_t i; 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++) { int hn, ln; char c; 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) & 0xFF; } return buffer; } char* freerdp_assistance_bin_to_hex_string(const BYTE* data, size_t size) { size_t i; char* p; int ln, hn; char bin2hex[] = "0123456789ABCDEF"; p = (char*) calloc((size + 1), 2); if (!p) return NULL; 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, const char* password) { char* p; char* q; char* r; 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'; errno = 0; { unsigned long val = strtoul(r, NULL, 0); free(r); if ((errno != 0) || (val > UINT32_MAX)) return -1; file->DtStart = val; } } /* 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'; errno = 0; { unsigned long val = strtoul(r, NULL, 0); free(r); if ((errno != 0) || (val > UINT32_MAX)) return -1; file->DtLength = val; } } /* 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; status = 0; switch (file->Type) { case 2: { file->EncryptedLHTicket = freerdp_assistance_hex_string_to_bin(file->LHTicket, &file->EncryptedLHTicketLength); if (!freerdp_assistance_decrypt2(file, password)) status = -1; } break; case 1: { if (!freerdp_assistance_parse_connection_string1(file)) status = -1; } break; default: return -1; } if (status < 0) { WLog_ERR(TAG, "freerdp_assistance_parse_connection_string1 failure: %d", status); return -1; } file->EncryptedPassStub = freerdp_assistance_encrypt_pass_stub(password, file->PassStub, &file->EncryptedPassStubLength); if (!file->EncryptedPassStub) return -1; return 1; } int freerdp_assistance_parse_file(rdpAssistanceFile* file, const char* name, const char* password) { int status; BYTE* buffer; FILE* fp = NULL; size_t readSize; INT64 fileSize; if (!name) return -1; free(file->filename); free(file->password); file->filename = _strdup(name); file->password = _strdup(password); fp = fopen(name, "r"); if (!fp) return -1; _fseeki64(fp, 0, SEEK_END); fileSize = _ftelli64(fp); _fseeki64(fp, 0, SEEK_SET); if (fileSize < 1) { fclose(fp); return -1; } buffer = (BYTE*) malloc(fileSize + 2); if (!buffer) { fclose(fp); return -1; } 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, password); free(buffer); return status; } BOOL freerdp_assistance_populate_settings_from_assistance_file(rdpAssistanceFile* file, rdpSettings* settings) { UINT32 i; freerdp_set_param_bool(settings, FreeRDP_RemoteAssistanceMode, TRUE); if (!file->RASessionId || !file->MachineAddresses) return FALSE; if (freerdp_set_param_string(settings, FreeRDP_RemoteAssistanceSessionId, file->RASessionId) != 0) return FALSE; if (file->RCTicket) { if (freerdp_set_param_string(settings, FreeRDP_RemoteAssistanceRCTicket, file->RCTicket) != 0) return FALSE; } else { if (freerdp_set_param_string(settings, FreeRDP_RemoteAssistanceRCTicket, file->ConnectionString2) != 0) return FALSE; } if (file->PassStub) { if (freerdp_set_param_string(settings, FreeRDP_RemoteAssistancePassStub, file->PassStub) != 0) return FALSE; } if (freerdp_set_param_string(settings, FreeRDP_ServerHostname, file->MachineAddresses[0]) != 0) return FALSE; if (freerdp_set_param_string(settings, FreeRDP_AssistanceFile, file->filename) != 0) return FALSE; if (freerdp_set_param_string(settings, FreeRDP_RemoteAssistancePassword, file->password) != 0) return FALSE; if (freerdp_set_param_string(settings, FreeRDP_Username, file->Username) != 0) return FALSE; settings->RemoteAssistanceMode = TRUE; freerdp_set_param_uint32(settings, FreeRDP_ServerPort, file->MachinePorts[0]); freerdp_target_net_addresses_free(settings); settings->TargetNetAddressCount = file->MachineCount; if (settings->TargetNetAddressCount) { settings->TargetNetAddresses = (char**) calloc(file->MachineCount, sizeof(char*)); settings->TargetNetPorts = (UINT32*) calloc(file->MachineCount, sizeof(UINT32)); if (!settings->TargetNetAddresses || !settings->TargetNetPorts) return FALSE; for (i = 0; i < settings->TargetNetAddressCount; i++) { settings->TargetNetAddresses[i] = _strdup(file->MachineAddresses[i]); settings->TargetNetPorts[i] = file->MachinePorts[i]; if (!settings->TargetNetAddresses[i]) return FALSE; } } return TRUE; } rdpAssistanceFile* freerdp_assistance_file_new(void) { return (rdpAssistanceFile*) calloc(1, sizeof(rdpAssistanceFile)); } void freerdp_assistance_file_free(rdpAssistanceFile* file) { UINT32 i; if (!file) return; free(file->filename); free(file->password); 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->EncryptedPassStub); for (i = 0; i < file->MachineCount; i++) { free(file->MachineAddresses[i]); } free(file->MachineAddresses); free(file->MachinePorts); free(file); } void freerdp_assistance_print_file(rdpAssistanceFile* file, wLog* log, DWORD level) { size_t x; WLog_Print(log, level, "Username: %s", file->Username); WLog_Print(log, level, "LHTicket: %s", file->LHTicket); WLog_Print(log, level, "RCTicket: %s", file->RCTicket); WLog_Print(log, level, "RCTicketEncrypted: %"PRId32, file->RCTicketEncrypted); WLog_Print(log, level, "PassStub: %s", file->PassStub); WLog_Print(log, level, "DtStart: %"PRIu32, file->DtStart); WLog_Print(log, level, "DtLength: %"PRIu32, file->DtLength); WLog_Print(log, level, "LowSpeed: %"PRId32, file->LowSpeed); WLog_Print(log, level, "RASessionId: %s", file->RASessionId); WLog_Print(log, level, "RASpecificParams: %s", file->RASpecificParams); for (x = 0; x < file->MachineCount; x++) { WLog_Print(log, level, "MachineAddress [%"PRIdz": %s", x, file->MachineAddresses[x]); WLog_Print(log, level, "MachinePort [%"PRIdz": %"PRIu32, x, file->MachinePorts[x]); } } BOOL freerdp_assistance_get_encrypted_pass_stub(rdpAssistanceFile* file, const char** pwd, size_t* size) { if (!file || !pwd || !size) return FALSE; *pwd = (const char*)file->EncryptedPassStub; *size = file->EncryptedPassStubLength; return TRUE; } int freerdp_assistance_set_connection_string2(rdpAssistanceFile* file, const char* string, const char* password) { if (!file || !string || !password) return -1; free(file->ConnectionString2); free(file->password); file->ConnectionString2 = _strdup(string); file->password = _strdup(password); return freerdp_assistance_parse_connection_string2(file); }