Libgourou

Libgourou Commit Details

Date:2022-12-21 20:56:26 (9 months 1 day ago)
Author:Grégory Soutadé
Branch:master
Commit:24bae89095f5ad12dfa516d114ed2058e874a74c
Parents: afab1c001258d32a268f2dfdbda976e403f42fdf
Message:Factorize decryptADEPTKey() for ePub and PDF
Changes:
Minclude/libgourou.h (1 diff)
Msrc/libgourou.cpp (8 diffs)

File differences

include/libgourou.h
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␉void fetchLicenseServiceCertificate(const std::string& licenseURL,␊
␉␉␉␉␉ const std::string& operatorURL);␊
␉std::string encryptedKeyFirstPass(pugi::xml_document& rightsDoc, const std::string& encryptedKey, const std::string& keyType);␊
␉void decryptADEPTKey(const std::string& encryptedKey, unsigned char* decryptedKey);␊
␉void decryptADEPTKey(pugi::xml_document& rightsDoc, unsigned char* decryptedKey, const unsigned char* encryptionKey=0, unsigned encryptionKeySize=0);␊
␉void removeEPubDRM(const std::string& filenameIn, const std::string& filenameOut, const unsigned char* encryptionKey, unsigned encryptionKeySize);␊
␉void generatePDFObjectKey(int version,␊
␉␉␉␉ const unsigned char* masterKey, unsigned int masterKeyLength,␊
src/libgourou.cpp
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int DRMProcessor::getLogLevel() {return (int)gourou::logLevel;}␊
void DRMProcessor::setLogLevel(int logLevel) {gourou::logLevel = (GOUROU_LOG_LEVEL)logLevel;}␊
␊
void DRMProcessor::decryptADEPTKey(const std::string& encryptedKey, unsigned char* decryptedKey)␊
{␉␊
␉if (encryptedKey.size() != 172)␊
␉ EXCEPTION(DRM_INVALID_KEY_SIZE, "Invalid encrypted key size (" << encryptedKey.size() << "). DRM version not supported");␊
␊
␉ByteArray arrayEncryptedKey = ByteArray::fromBase64(encryptedKey);␊
␊
␉std::string privateKeyData = user->getPrivateLicenseKey();␊
␉ByteArray privateRSAKey = ByteArray::fromBase64(privateKeyData);␊
␉␊
␉dumpBuffer(gourou::LG_LOG_DEBUG, "To decrypt : ", arrayEncryptedKey.data(), arrayEncryptedKey.length());␊
␊
␉client->RSAPrivateDecrypt(privateRSAKey.data(), privateRSAKey.length(),␊
␉␉␉␉ RSAInterface::RSA_KEY_PKCS8, "",␊
␉␉␉␉ arrayEncryptedKey.data(), arrayEncryptedKey.length(), decryptedKey);␊
}␊
␊
/**␊
* RSA Key can be over encrypted with AES128-CBC if keyType attribute is set␊
* remainder = keyType % 16␊
␉for(unsigned int i=0; i<sizeof(iv); i++)␊
␉ iv[i] = _deviceId[i] ^ _fulfillmentId[i] ^ _voucherId[i];␊
␊
␉ByteArray arrayEncryptedKey = ByteArray::fromBase64(encryptedKey);␊
␉␉␊
␉dumpBuffer(gourou::LG_LOG_DEBUG, "First pass key : ", key, sizeof(key));␊
␉dumpBuffer(gourou::LG_LOG_DEBUG, "First pass IV : ", iv, sizeof(iv));␊
␊
␉ByteArray arrayEncryptedKey = ByteArray::fromBase64(encryptedKey);␊
␉unsigned char* clearRSAKey = new unsigned char[arrayEncryptedKey.size()];␊
␊
␉client->decrypt(CryptoInterface::ALGO_AES, CryptoInterface::CHAIN_CBC,␊
␊
␉return res.toBase64();␊
}␊
␊
void DRMProcessor::removeEPubDRM(const std::string& filenameIn, const std::string& filenameOut,␊
␉␉␉␉ const unsigned char* encryptionKey, unsigned encryptionKeySize)␊
{␊
␉ByteArray zipData;␊
␉bool removeEncryptionXML = true;␊
␉void* zipHandler = client->zipOpen(filenameOut);␊
␊
␉client->zipReadFile(zipHandler, "META-INF/rights.xml", zipData);␊
␉pugi::xml_document rightsDoc;␊
␉rightsDoc.load_string((const char*)zipData.data());␊
␊
␉std::string encryptedKey = extractTextElem(rightsDoc, "/adept:rights/licenseToken/encryptedKey");␊
␉unsigned char decryptedKey[RSA_KEY_SIZE];␊
␊
void DRMProcessor::decryptADEPTKey(pugi::xml_document& rightsDoc, unsigned char* decryptedKey, const unsigned char* encryptionKey, unsigned encryptionKeySize)␊
{␊
␉unsigned char rsaKey[RSA_KEY_SIZE];␊
␉␊
␉if (!encryptionKey)␊
␉{␊
␉ std::string encryptedKey = extractTextElem(rightsDoc, "/adept:rights/licenseToken/encryptedKey");␊
␉ std::string keyType = extractTextAttribute(rightsDoc, "/adept:rights/licenseToken/encryptedKey", "keyType", false);␊
␊
␉ if (keyType != "")␊
␉␉encryptedKey = encryptedKeyFirstPass(rightsDoc, encryptedKey, keyType);␊
␉ ␊
␉ decryptADEPTKey(encryptedKey, decryptedKey);␊
␉ if (encryptedKey.size() != 172)␊
␉␉EXCEPTION(DRM_INVALID_KEY_SIZE, "Invalid encrypted key size (" << encryptedKey.size() << "). DRM version not supported");␊
␊
␉ ByteArray arrayEncryptedKey = ByteArray::fromBase64(encryptedKey);␊
␊
␉ std::string privateKeyData = user->getPrivateLicenseKey();␊
␉ ByteArray privateRSAKey = ByteArray::fromBase64(privateKeyData);␊
␉␊
␉ dumpBuffer(gourou::LG_LOG_DEBUG, "To decrypt : ", arrayEncryptedKey.data(), arrayEncryptedKey.length());␊
␊
␉ client->RSAPrivateDecrypt(privateRSAKey.data(), privateRSAKey.length(),␊
␉␉␉␉ RSAInterface::RSA_KEY_PKCS8, "",␊
␉␉␉␉ arrayEncryptedKey.data(), arrayEncryptedKey.length(), rsaKey);␊
␊
␉ dumpBuffer(gourou::LG_LOG_DEBUG, "Decrypted : ", decryptedKey, RSA_KEY_SIZE);␊
␉ dumpBuffer(gourou::LG_LOG_DEBUG, "Decrypted : ", rsaKey, sizeof(rsaKey));␊
␊
␉ if (decryptedKey[0] != 0x00 || decryptedKey[1] != 0x02 ||␊
␉␉decryptedKey[RSA_KEY_SIZE-16-1] != 0x00)␊
␉ if (rsaKey[0] != 0x00 || rsaKey[1] != 0x02 ||␊
␉␉rsaKey[RSA_KEY_SIZE-16-1] != 0x00)␊
␉␉EXCEPTION(DRM_ERR_ENCRYPTION_KEY, "Unable to retrieve encryption key");␊
␊
␉ memcpy(decryptedKey, &rsaKey[sizeof(rsaKey)-16], 16);␊
␉}␊
␉else␊
␉{␊
␉ if (encryptionKeySize != 16)␊
␉␉EXCEPTION(DRM_ERR_ENCRYPTION_KEY, "Provided encryption key must be 16 bytes");␊
␊
␉ memcpy(&decryptedKey[sizeof(decryptedKey)-16], encryptionKey, encryptionKeySize);␊
␉ memcpy(decryptedKey, encryptionKey, encryptionKeySize);␊
␉}␊
}␊
␊
void DRMProcessor::removeEPubDRM(const std::string& filenameIn, const std::string& filenameOut,␊
␉␉␉␉ const unsigned char* encryptionKey, unsigned encryptionKeySize)␊
{␊
␉ByteArray zipData;␊
␉bool removeEncryptionXML = true;␊
␉void* zipHandler = client->zipOpen(filenameOut);␊
␊
␉client->zipReadFile(zipHandler, "META-INF/rights.xml", zipData);␊
␉pugi::xml_document rightsDoc;␊
␉rightsDoc.load_string((const char*)zipData.data());␊
␊
␉unsigned char decryptedKey[16];␊
␊
␉decryptADEPTKey(rightsDoc, decryptedKey, encryptionKey, encryptionKeySize);␊
␉␊
␉client->zipReadFile(zipHandler, "META-INF/encryption.xml", zipData);␊
␉pugi::xml_document encryptionDoc;␊
␉␉unsigned int dataOutLength;␊
␊
␉␉client->decrypt(CryptoInterface::ALGO_AES, CryptoInterface::CHAIN_CBC,␊
␉␉␉␉decryptedKey+sizeof(decryptedKey)-16, 16, /* Key */␊
␉␉␉␉decryptedKey, sizeof(decryptedKey), /* Key */␊
␉␉␉␉_data, 16, /* IV */␊
␉␉␉␉&_data[16], zipData.length()-16,␊
␉␉␉␉_clearData, &dataOutLength);␊
␉std::vector<uPDFParser::Object*> objects = parser.objects();␊
␉std::vector<uPDFParser::Object*>::iterator it;␊
␉std::vector<uPDFParser::Object*>::reverse_iterator rIt;␊
␉unsigned char decryptedKey[RSA_KEY_SIZE];␊
␉unsigned char decryptedKey[16];␊
␉int ebxId;␊
␉␊
␉for(rIt = objects.rbegin(); rIt != objects.rend(); rIt++)␊
␉␉pugi::xml_document rightsDoc;␊
␉␉rightsDoc.load_string((const char*)rightsStr.data());␊
␊
␉␉std::string encryptedKey = extractTextElem(rightsDoc, "/adept:rights/licenseToken/encryptedKey");␊
␊
␉␉if (!encryptionKey)␊
␉␉{␊
␉␉ std::string keyType = extractTextAttribute(rightsDoc, "/adept:rights/licenseToken/encryptedKey", "keyType", false);␊
␊
␉␉ if (keyType != "")␊
␉␉␉encryptedKey = encryptedKeyFirstPass(rightsDoc, encryptedKey, keyType);␊
␉␉ ␊
␉␉ decryptADEPTKey(encryptedKey, decryptedKey);␊
␊
␉␉ dumpBuffer(gourou::LG_LOG_DEBUG, "Decrypted : ", decryptedKey, RSA_KEY_SIZE);␊
␊
␉␉ if (decryptedKey[0] != 0x00 || decryptedKey[1] != 0x02 ||␊
␉␉␉decryptedKey[RSA_KEY_SIZE-16-1] != 0x00)␊
␉␉␉EXCEPTION(DRM_ERR_ENCRYPTION_KEY, "Unable to retrieve encryption key");␊
␉␉}␊
␉␉else␊
␉␉{␊
␉␉ GOUROU_LOG(DEBUG, "Use provided encryption key");␊
␉␉ if (encryptionKeySize != 16)␊
␉␉␉EXCEPTION(DRM_ERR_ENCRYPTION_KEY, "Provided encryption key must be 16 bytes");␊
␊
␉␉ memcpy(&decryptedKey[sizeof(decryptedKey)-16], encryptionKey, encryptionKeySize);␊
␉␉}␊
␉␉decryptADEPTKey(rightsDoc, decryptedKey, encryptionKey, encryptionKeySize);␊
␉␉␊
␉␉ebxId = ebx->objectId();␊
␊
␉ ␊
␉ GOUROU_LOG(DEBUG, "Obj " << object->objectId());␊
␊
␉ unsigned char tmpKey[16];␊
␉ unsigned char tmpKey[sizeof(decryptedKey)];␊
␊
␉ generatePDFObjectKey(ebxVersion->value(),␊
␉␉␉␉ decryptedKey+sizeof(decryptedKey)-16, 16,␊
␉␉␉␉ decryptedKey, sizeof(decryptedKey),␊
␉␉␉␉ object->objectId(), object->generationNumber(),␊
␉␉␉␉ tmpKey);␊
␊

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