Libgourou

Libgourou Commit Details

Date:2022-08-27 15:44:27 (1 year 26 days ago)
Author:Grégory Soutadé
Branch:master
Commit:7b8c7acbadf5dbdbba534899ea0ab55db1102a64
Parents: 56b3231f92e327d841d5775ebcf9cd757e630c28
Message:Compute first pass for encryptedKey if keyType attribute is set
Changes:
Minclude/drmprocessorclient.h (1 diff)
Minclude/libgourou.h (1 diff)
Minclude/libgourou_common.h (5 diffs)
Msrc/libgourou.cpp (2 diffs)
Mutils/Makefile (1 diff)

File differences

include/drmprocessorclient.h
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public:␊
␉enum RSA_KEY_TYPE {␊
␉ RSA_KEY_PKCS12 = 0,␊
␉ RSA_KEY_PKCS8,␊
␉ RSA_KEY_X509␊
␉};␊
␊
include/libgourou.h
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␉void buildSignInRequest(pugi::xml_document& signInRequest, const std::string& adobeID, const std::string& adobePassword, const std::string& authenticationCertificate);␊
␉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 removeEPubDRM(const std::string& filenameIn, const std::string& filenameOut, const unsigned char* encryptionKey, unsigned encryptionKeySize);␊
␉void generatePDFObjectKey(int version,␊
include/libgourou_common.h
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␉DRM_FORMAT_NOT_SUPPORTED,␊
␉DRM_IN_OUT_EQUALS,␊
␉DRM_MISSING_PARAMETER,␊
␉DRM_INVALID_KEY_SIZE␊
␉DRM_INVALID_KEY_SIZE,␊
␉DRM_ERR_ENCRYPTION_KEY_FP␊
};␊
␊
/**␊
* It can throw an exception if tag does not exists␊
* or just return an empty value␊
*/␊
static inline std::string extractTextElem(const pugi::xml_document& doc, const char* tagName, bool throwOnNull=true)␊
static inline std::string extractTextElem(const pugi::xml_node& root, const char* tagName, bool throwOnNull=true)␊
{␊
pugi::xpath_node xpath_node = doc.select_node(tagName);␊
pugi::xpath_node xpath_node = root.select_node(tagName);␊
␊
if (!xpath_node)␊
␉{␊
return trim(res);␊
}␊
␊
static inline std::string extractTextElem(const pugi::xml_node& doc, const char* tagName, bool throwOnNull=true)␊
/**␊
* @brief Extract text attribute from tag in document␊
* It can throw an exception if attribute does not exists␊
* or just return an empty value␊
*/␊
static inline std::string extractTextAttribute(const pugi::xml_node& root, const char* tagName, const char* attributeName, bool throwOnNull=true)␊
{␊
pugi::xpath_node xpath_node = doc.select_node(tagName);␊
pugi::xpath_node xpath_node = root.select_node(tagName);␊
␊
if (!xpath_node)␊
␉{␊
return "";␊
␉}␊
␊
␉pugi::xml_node node = xpath_node.node().first_child();␊
␉pugi::xml_attribute attr = xpath_node.node().attribute(attributeName);␊
␊
␉if (!node)␊
␉if (!attr)␊
␉{␊
␉ if (throwOnNull)␊
␉␉EXCEPTION(GOUROU_TAG_NOT_FOUND, "Text element for tag " << tagName << " not found");␊
␉␉EXCEPTION(GOUROU_TAG_NOT_FOUND, "Attribute element " << attributeName << " for tag " << tagName << " not found");␊
␉ ␊
return "";␊
␉}␊
␊
␉std::string res = node.value();␊
return trim(res);␊
␉std::string res = attr.value();␊
␉return trim(res);␊
}␊
␊
/**␊
␉node.append_child(pugi::node_pcdata).set_value(value.c_str());␊
}␊
␊
/**␊
* Remove "urn:uuid:" prefix and all '-' from uuid␊
* urn:uuid:9cb786e8-586a-4950-8901-fff8d2ee6025␊
* ->␊
* 9cb786e8586a49508901fff8d2ee6025␊
*/␊
static inline std::string extractIdFromUUID(const std::string& uuid)␊
{␊
␉unsigned int i = 0;␊
␉std::string res;␊
␉␊
␉if (uuid.find("urn:uuid:") == 0)␊
␉ i = 9;␊
␊
␉for(; i<uuid.size(); i++)␊
␉{␊
␉ if (uuid[i] != '-')␊
␉␉res += uuid[i];␊
␉}␊
␊
␉return res;␊
}␊
␊
/**␊
* @brief Open a file descriptor on path. If it already exists and truncate == true, it's truncated␊
*␊
src/libgourou.cpp
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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);␊
␊
␉ByteArray deviceKey(device->getDeviceKey(), Device::DEVICE_KEY_SIZE);␊
␉std::string pkcs12 = user->getPKCS12();␊
␉␊
␉dumpBuffer(gourou::LG_LOG_DEBUG, "To decrypt : ", arrayEncryptedKey.data(), arrayEncryptedKey.length());␊
␊
␉client->RSAPrivateDecrypt(privateRSAKey.data(), privateRSAKey.length(),␊
␉␉␉␉ RSAInterface::RSA_KEY_PKCS12, deviceKey.toBase64().data(),␊
␉␉␉␉ RSAInterface::RSA_KEY_PKCS8, "",␊
␉␉␉␉ arrayEncryptedKey.data(), arrayEncryptedKey.length(), decryptedKey);␊
␊
␉if (decryptedKey[0] != 0x00 || decryptedKey[1] != 0x02 ||␊
␉ decryptedKey[RSA_KEY_SIZE-16-1] != 0x00)␊
␉ EXCEPTION(DRM_ERR_ENCRYPTION_KEY, "Unable to retrieve encryption key");␊
}␊
␊
/**␊
* RSA Key can be over encrypted with AES128-CBC if keyType attribute is set␊
* Key = SHA256(keyType)[14:22] || SHA256(keyType)[7:13]␊
* IV = DeviceID ^ FulfillmentId ^ VoucherId␊
*␊
* @return Base64 encoded decrypted key␊
*/␊
std::string DRMProcessor::encryptedKeyFirstPass(pugi::xml_document& rightsDoc, const std::string& encryptedKey, const std::string& keyType)␊
{␊
␉unsigned char digest[32], key[16], iv[16];␊
␉unsigned int dataOutLength;␊
␉std::string id;␊
␉␉␊
␉client->digest("SHA256", (unsigned char*)keyType.c_str(), keyType.size(), digest);␊
␉memcpy(key, &digest[14], 9);␊
␉memcpy(&key[9], &digest[7], 7);␊
␊
␉id = extractTextElem(rightsDoc, "/adept:rights/licenseToken/device");␊
␉if (id == "")␊
␉ EXCEPTION(DRM_ERR_ENCRYPTION_KEY_FP, "Device id not found in rights.xml");␊
␉ByteArray deviceId = ByteArray::fromHex(extractIdFromUUID(id));␊
␉unsigned char* _deviceId = deviceId.data();␊
␉␉␊
␉id = extractTextElem(rightsDoc, "/adept:rights/licenseToken/fulfillment");␊
␉if (id == "")␊
␉ EXCEPTION(DRM_ERR_ENCRYPTION_KEY_FP, "Fulfillment id not found in rights.xml");␊
␉ByteArray fulfillmentId = ByteArray::fromHex(extractIdFromUUID(id));␊
␉unsigned char* _fulfillmentId = fulfillmentId.data();␊
␉␉␊
␉id = extractTextElem(rightsDoc, "/adept:rights/licenseToken/voucher");␊
␉if (id == "")␊
␉ EXCEPTION(DRM_ERR_ENCRYPTION_KEY_FP, "Voucher id not found in rights.xml");␊
␉ByteArray voucherId = ByteArray::fromHex(extractIdFromUUID(id));␊
␉unsigned char* _voucherId = voucherId.data();␊
␉␉␊
␉if (deviceId.size() < sizeof(iv) || fulfillmentId.size() < sizeof(iv) || voucherId.size() < sizeof(iv))␊
␉ EXCEPTION(DRM_ERR_ENCRYPTION_KEY_FP, "One id has a bad length");␊
␊
␉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));␊
␊
␉unsigned char* clearRSAKey = new unsigned char[arrayEncryptedKey.size()];␊
␉␊
␉client->Decrypt(CryptoInterface::ALGO_AES, CryptoInterface::CHAIN_CBC,␊
␉␉␉(const unsigned char*)key, (unsigned int)sizeof(key),␊
␉␉␉(const unsigned char*)iv, (unsigned int)sizeof(iv),␊
␉␉␉(const unsigned char*)arrayEncryptedKey.data(), arrayEncryptedKey.size(),␊
␉␉␉(unsigned char*)clearRSAKey, &dataOutLength);␊
␊
␉dumpBuffer(gourou::LG_LOG_DEBUG, "\nDecrypted key : ", clearRSAKey, dataOutLength);␊
␊
␉/* Last block could be 0x10*16 which is OpenSSL padding, remove it if it's the case */␊
␉bool skipLastLine = true;␊
␉for(unsigned int i=dataOutLength-16; i<dataOutLength; i++)␊
␉{␊
␉ if (clearRSAKey[i] != 0x10)␊
␉ {␊
␉␉skipLastLine = false;␊
␉␉break;␊
␉ }␊
␉}␊
␊
␉ByteArray res(clearRSAKey, (skipLastLine)?dataOutLength-16:dataOutLength);␊
␊
␉delete[] clearRSAKey;␊
␊
␉return res.toBase64();␊
}␊
␊
void DRMProcessor::removeEPubDRM(const std::string& filenameIn, const std::string& filenameOut,␊
␉␉␉␉ const unsigned char* encryptionKey, unsigned encryptionKeySize)␊
␉unsigned char decryptedKey[RSA_KEY_SIZE];␊
␊
␉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");␊
utils/Makefile
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␉$(CXX) $(CXXFLAGS) $^ $(LDFLAGS) -o $@␊
␊
clean:␊
␉rm -f $(TARGETS)␊
␉rm -f $(TARGETS) $(COMMON_LIB)␊
␊
ultraclean: clean␊

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