/*
 *  Phusion Passenger - https://www.phusionpassenger.com/
 *  Copyright (c) 2010-2018 Phusion Holding B.V.
 *
 *  "Passenger", "Phusion Passenger" and "Union Station" are registered
 *  trademarks of Phusion Holding B.V.
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *  THE SOFTWARE.
 */
#ifndef _PASSENGER_SECURITY_KIT_CRYPTO_H_
#define _PASSENGER_SECURITY_KIT_CRYPTO_H_

#include <boost/function.hpp>
#include <boost/thread.hpp>
#include <modp_b64.h>

#if BOOST_OS_MACOS
#include <Availability.h>
#ifndef __MAC_10_13
#define __MAC_10_13 101300
#endif
#include <CoreFoundation/CoreFoundation.h>
#include <Security/Security.h>
#define PRE_HIGH_SIERRA (__MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_13)
#else
#include <openssl/pem.h>
#include <openssl/rand.h>
#include <openssl/err.h>
#endif

#include <StaticString.h>

namespace Passenger {

#if BOOST_OS_MACOS
typedef SecKeyRef PUBKEY_TYPE;
#else
typedef RSA* PUBKEY_TYPE;
#endif

using namespace std;
using namespace boost;
using namespace oxt;

struct AESEncResult {
	unsigned char *encrypted;
	size_t encryptedLen;
	unsigned char *key;
	size_t keyLen;
	unsigned char *iv;
	size_t ivLen;
};

class Crypto {
private:
	/**
	 * @returns new PUBKEY_TYPE; user is responsible for free (with freePubKey)
	 */
	PUBKEY_TYPE loadPubKey(const char *filename);

	/**
	 * free a PUBKEY_TYPE (loaded with loadPubKey); may be NULL
	 */
	void freePubKey(PUBKEY_TYPE);

	void logError(const StaticString &error);

	/**
	 * log prefix using P_ERROR, and (library-specific) detail from either additional or global query
	 */
#if BOOST_OS_MACOS
	CFDataRef id;
	// (additional needs to be defined as a CFErrorRef, void * won't work)
	void logFreeErrorExtended(const StaticString &prefix, CFErrorRef &additional);
	CFDictionaryRef createQueryDict(const char *label);
	SecAccessRef createAccess(const char *cLabel);
	OSStatus copyIdentityFromPKCS12File(const char *cPath, const char *cPassword, const char *cLabel);
	CFDataRef genIV(size_t iv_size);
	bool getKeyBytes(SecKeyRef cryptokey, void **target, size_t &len);
	bool memoryBridge(CFDataRef input, void **target, size_t &len);
	bool innerMemoryBridge(void *input, void **target, size_t len);
#else
	void logErrorExtended(const StaticString &prefix);
#endif

public:
	Crypto();
	~Crypto();

	/**
	 * Generates a nonce consisting of a timestamp (usec) and a random (base64) part.
	 */
	bool generateAndAppendNonce(string &nonce);

#if BOOST_OS_MACOS
	bool generateRandomChars(unsigned char *rndChars, int rndLen);
#endif

	/**
	 * Generate an AES key and encrypt dataChars with it. The resulting encrypted characters, together with the AES key
	 * and iv that were used appears in AESEncrypted. Memory is allocated for it, and it must be freed with freeAESEncrypted().
	 *
	 * N.B. only used in Enterprise (to enable additional services), but open sourced for transparency.
	 */
	bool encryptAES256(char *dataChars, size_t dataLen, AESEncResult &aesEnc);

	/**
	 * Releases resources returned by encryptAES256().
	 */
	void freeAESEncrypted(AESEncResult &aesEnc);

	/**
	 * Encrypt a (short) bit of date with specified public key. Memory is allocated for the result encryptedCharsPtr, which
	 * must be free()d manually.
	 *
	 * N.B. only used in Enterprise (to enable additional services), but open sourced for transparency.
	 */
	bool encryptRSA(unsigned char *dataChars, size_t dataLen,
			string encryptPubKeyPath, unsigned char **encryptedCharsPtr, size_t &encryptedLen);

	/**
	 * @returns true if specified signature is from the entity known by its (public) key at signaturePubKeyPath,
	 * and valid for speficied data.
	 */
	bool verifySignature(string signaturePubKeyPath, char *signatureChars, int signatureLen, string data);

};

} // namespace Passenger

#endif /* _PASSENGER_SECURITYKIT_CRYPTO_H_ */