//-----------------------------------------------------------------------------
// Copyright (C) 2018 Merlok
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// FIDO2 authenticators core data and commands
// https://fidoalliance.org/specs/fido-v2.0-id-20180227/fido-client-to-authenticator-protocol-v2.0-id-20180227.html
//-----------------------------------------------------------------------------
//

#include "fidocore.h"
#include "emv/emvcore.h"
#include "emv/emvjson.h"
#include <cbor.h>
#include "cbortools.h"
#include <mbedtls/x509_crt.h>
#include <mbedtls/x509.h>
#include <mbedtls/pk.h>
#include "crypto/asn1utils.h"
#include "crypto/libpcrypto.h"
#include "fido/additional_ca.h"

typedef struct {
	uint8_t ErrorCode;
	char *ShortDescription;
	char *Description;
} fido2Error_t;

fido2Error_t fido2Errors[] = {
	{0xFF, "n/a",									"n/a"},
	{0x00, "CTAP1_ERR_SUCCESS",					"Indicates successful response."},
	{0x01, "CTAP1_ERR_INVALID_COMMAND",			"The command is not a valid CTAP command."},
	{0x02, "CTAP1_ERR_INVALID_PARAMETER",		"The command included an invalid parameter."},
	{0x03, "CTAP1_ERR_INVALID_LENGTH",			"Invalid message or item length."},
	{0x04, "CTAP1_ERR_INVALID_SEQ",				"Invalid message sequencing."},
	{0x05, "CTAP1_ERR_TIMEOUT",					"Message timed out."},
	{0x06, "CTAP1_ERR_CHANNEL_BUSY",			"Channel busy."},
	{0x0A, "CTAP1_ERR_LOCK_REQUIRED",			"Command requires channel lock."},
	{0x0B, "CTAP1_ERR_INVALID_CHANNEL",			"Command not allowed on this cid."},
	{0x10, "CTAP2_ERR_CBOR_PARSING",			"Error while parsing CBOR."},
	{0x11, "CTAP2_ERR_CBOR_UNEXPECTED_TYPE",	"Invalid/unexpected CBOR error."},
	{0x12, "CTAP2_ERR_INVALID_CBOR",			"Error when parsing CBOR."},
	{0x13, "CTAP2_ERR_INVALID_CBOR_TYPE",		"Invalid or unexpected CBOR type."},
	{0x14, "CTAP2_ERR_MISSING_PARAMETER",		"Missing non-optional parameter."},
	{0x15, "CTAP2_ERR_LIMIT_EXCEEDED",			"Limit for number of items exceeded."},
	{0x16, "CTAP2_ERR_UNSUPPORTED_EXTENSION",	"Unsupported extension."},
	{0x17, "CTAP2_ERR_TOO_MANY_ELEMENTS",		"Limit for number of items exceeded."},
	{0x18, "CTAP2_ERR_EXTENSION_NOT_SUPPORTED",	"Unsupported extension."},
	{0x19, "CTAP2_ERR_CREDENTIAL_EXCLUDED",		"Valid credential found in the exludeList."},
	{0x20, "CTAP2_ERR_CREDENTIAL_NOT_VALID",	"Credential not valid for authenticator."},
	{0x21, "CTAP2_ERR_PROCESSING",				"Processing (Lengthy operation is in progress)."},
	{0x22, "CTAP2_ERR_INVALID_CREDENTIAL",		"Credential not valid for the authenticator."},
	{0x23, "CTAP2_ERR_USER_ACTION_PENDING",		"Authentication is waiting for user interaction."},
	{0x24, "CTAP2_ERR_OPERATION_PENDING",		"Processing, lengthy operation is in progress."},
	{0x25, "CTAP2_ERR_NO_OPERATIONS",			"No request is pending."},
	{0x26, "CTAP2_ERR_UNSUPPORTED_ALGORITHM",	"Authenticator does not support requested algorithm."},
	{0x27, "CTAP2_ERR_OPERATION_DENIED",		"Not authorized for requested operation."},
	{0x28, "CTAP2_ERR_KEY_STORE_FULL",			"Internal key storage is full."},
	{0x29, "CTAP2_ERR_NOT_BUSY",				"Authenticator cannot cancel as it is not busy."},
	{0x2A, "CTAP2_ERR_NO_OPERATION_PENDING",	"No outstanding operations."},
	{0x2B, "CTAP2_ERR_UNSUPPORTED_OPTION",		"Unsupported option."},
	{0x2C, "CTAP2_ERR_INVALID_OPTION",			"Unsupported option."},
	{0x2D, "CTAP2_ERR_KEEPALIVE_CANCEL",		"Pending keep alive was cancelled."},
	{0x2E, "CTAP2_ERR_NO_CREDENTIALS",			"No valid credentials provided."},
	{0x2F, "CTAP2_ERR_USER_ACTION_TIMEOUT",		"Timeout waiting for user interaction."},
	{0x30, "CTAP2_ERR_NOT_ALLOWED",				"Continuation command, such as, authenticatorGetNextAssertion not allowed."},
	{0x31, "CTAP2_ERR_PIN_INVALID",				"PIN Blocked."},
	{0x32, "CTAP2_ERR_PIN_BLOCKED",				"PIN Blocked."},
	{0x33, "CTAP2_ERR_PIN_AUTH_INVALID",		"PIN authentication,pinAuth, verification failed."},
	{0x34, "CTAP2_ERR_PIN_AUTH_BLOCKED",		"PIN authentication,pinAuth, blocked. Requires power recycle to reset."},
	{0x35, "CTAP2_ERR_PIN_NOT_SET",				"No PIN has been set."},
	{0x36, "CTAP2_ERR_PIN_REQUIRED",			"PIN is required for the selected operation."},
	{0x37, "CTAP2_ERR_PIN_POLICY_VIOLATION",	"PIN policy violation. Currently only enforces minimum length."},
	{0x38, "CTAP2_ERR_PIN_TOKEN_EXPIRED",		"pinToken expired on authenticator."},
	{0x39, "CTAP2_ERR_REQUEST_TOO_LARGE",		"Authenticator cannot handle this request due to memory constraints."},
	{0x7F, "CTAP1_ERR_OTHER",					"Other unspecified error."},
	{0xDF, "CTAP2_ERR_SPEC_LAST", 				"CTAP 2 spec last error."},
};

typedef struct {
	fido2Commands Command;
	fido2PacketType PckType;
	uint8_t MemberNumber;
	char *Description;
} fido2Desc_t;

fido2Desc_t fido2CmdGetInfoRespDesc[] = {
	{fido2CmdMakeCredential, 	ptResponse, 0x01, "fmt"},
	{fido2CmdMakeCredential, 	ptResponse, 0x02, "authData"},
	{fido2CmdMakeCredential, 	ptResponse, 0x03, "attStmt"},

	{fido2CmdMakeCredential, 	ptQuery,    0x01, "clientDataHash"},
	{fido2CmdMakeCredential, 	ptQuery,    0x02, "rp"},
	{fido2CmdMakeCredential, 	ptQuery,    0x03, "user"},
	{fido2CmdMakeCredential, 	ptQuery,    0x04, "pubKeyCredParams"},
	{fido2CmdMakeCredential, 	ptQuery,    0x05, "excludeList"},
	{fido2CmdMakeCredential, 	ptQuery,    0x06, "extensions"},
	{fido2CmdMakeCredential, 	ptQuery,    0x07, "options"},
	{fido2CmdMakeCredential, 	ptQuery,    0x08, "pinAuth"},
	{fido2CmdMakeCredential, 	ptQuery,    0x09, "pinProtocol"},
	
	{fido2CmdGetAssertion, 		ptResponse, 0x01, "credential"},
	{fido2CmdGetAssertion, 		ptResponse, 0x02, "authData"},
	{fido2CmdGetAssertion, 		ptResponse, 0x03, "signature"},
	{fido2CmdGetAssertion, 		ptResponse, 0x04, "publicKeyCredentialUserEntity"},
	{fido2CmdGetAssertion, 		ptResponse, 0x05, "numberOfCredentials"},

	{fido2CmdGetAssertion, 		ptQuery,    0x01, "rpId"},
	{fido2CmdGetAssertion, 		ptQuery,    0x02, "clientDataHash"},
	{fido2CmdGetAssertion, 		ptQuery,    0x03, "allowList"},
	{fido2CmdGetAssertion, 		ptQuery,    0x04, "extensions"},
	{fido2CmdGetAssertion, 		ptQuery,    0x05, "options"},
	{fido2CmdGetAssertion, 		ptQuery,    0x06, "pinAuth"},
	{fido2CmdGetAssertion, 		ptQuery,    0x07, "pinProtocol"},
	
	{fido2CmdGetNextAssertion, 	ptResponse, 0x01, "credential"},
	{fido2CmdGetNextAssertion, 	ptResponse, 0x02, "authData"},
	{fido2CmdGetNextAssertion, 	ptResponse, 0x03, "signature"},
	{fido2CmdGetNextAssertion, 	ptResponse, 0x04, "publicKeyCredentialUserEntity"},
	
	{fido2CmdGetInfo, 			ptResponse, 0x01, "versions"},
	{fido2CmdGetInfo, 			ptResponse, 0x02, "extensions"},
	{fido2CmdGetInfo, 			ptResponse, 0x03, "aaguid"},
	{fido2CmdGetInfo, 			ptResponse, 0x04, "options"},
	{fido2CmdGetInfo, 			ptResponse, 0x05, "maxMsgSize"},
	{fido2CmdGetInfo, 			ptResponse, 0x06, "pinProtocols"},

	{fido2CmdClientPIN, 		ptResponse, 0x01, "keyAgreement"},
	{fido2CmdClientPIN, 		ptResponse, 0x02, "pinToken"},
	{fido2CmdClientPIN, 		ptResponse, 0x03, "retries"},

	{fido2CmdClientPIN, 		ptQuery,    0x01, "pinProtocol"},
	{fido2CmdClientPIN, 		ptQuery,    0x02, "subCommand"},
	{fido2CmdClientPIN, 		ptQuery,    0x03, "keyAgreement"},
	{fido2CmdClientPIN, 		ptQuery,    0x04, "pinAuth"},
	{fido2CmdClientPIN, 		ptQuery,    0x05, "newPinEnc"},
	{fido2CmdClientPIN, 		ptQuery,    0x06, "pinHashEnc"},
	{fido2CmdClientPIN, 		ptQuery,    0x07, "getKeyAgreement"},
	{fido2CmdClientPIN, 		ptQuery,    0x08, "getRetries"},
};

char *fido2GetCmdErrorDescription(uint8_t errorCode) {
	for (int i = 0; i < sizeof(fido2Errors) / sizeof(fido2Error_t); i++)
		if (fido2Errors[i].ErrorCode == errorCode)
			return fido2Errors[i].Description;
		
	return fido2Errors[0].Description;
}

char *fido2GetCmdMemberDescription(uint8_t cmdCode, bool isResponse, uint8_t memberNum) {
	for (int i = 0; i < sizeof(fido2CmdGetInfoRespDesc) / sizeof(fido2Desc_t); i++)
		if (fido2CmdGetInfoRespDesc[i].Command == cmdCode &&
			fido2CmdGetInfoRespDesc[i].PckType == (isResponse ? ptResponse : ptQuery) &&
			fido2CmdGetInfoRespDesc[i].MemberNumber == memberNum )
			return fido2CmdGetInfoRespDesc[i].Description;

	return NULL;
}

int FIDOSelect(bool ActivateField, bool LeaveFieldON, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	uint8_t data[] = {0xA0, 0x00, 0x00, 0x06, 0x47, 0x2F, 0x00, 0x01};
	
	return EMVSelect(ActivateField, LeaveFieldON, data, sizeof(data), Result, MaxResultLen, ResultLen, sw, NULL);
}

int FIDOExchange(sAPDU apdu, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	int res = EMVExchange(true, apdu, Result, MaxResultLen, ResultLen, sw, NULL);
	if (res == 5) // apdu result (sw) not a 0x9000
		res = 0;
	// software chaining
	while (!res && (*sw >> 8) == 0x61) {
		size_t oldlen = *ResultLen;
		res = EMVExchange(true, (sAPDU){0x00, 0xC0, 0x00, 0x00, 0x00, NULL}, &Result[oldlen], MaxResultLen - oldlen, ResultLen, sw, NULL);
		if (res == 5) // apdu result (sw) not a 0x9000
			res = 0;
		
		*ResultLen += oldlen;
		if (*ResultLen > MaxResultLen) 
			return 100;
	}
	return res;
}

int FIDORegister(uint8_t *params, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	return FIDOExchange((sAPDU){0x00, 0x01, 0x03, 0x00, 64, params}, Result, MaxResultLen, ResultLen, sw);
}

int FIDOAuthentication(uint8_t *params, uint8_t paramslen, uint8_t controlb, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	return FIDOExchange((sAPDU){0x00, 0x02, controlb, 0x00, paramslen, params}, Result, MaxResultLen, ResultLen, sw);
}

int FIDO2GetInfo(uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	uint8_t data[] = {fido2CmdGetInfo};
	return FIDOExchange((sAPDU){0x80, 0x10, 0x00, 0x00, sizeof(data), data}, Result, MaxResultLen, ResultLen, sw);
}

int FIDO2MakeCredential(uint8_t *params, uint8_t paramslen, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	uint8_t data[paramslen + 1];
	data[0] = fido2CmdMakeCredential;
	memcpy(&data[1], params, paramslen);
	return FIDOExchange((sAPDU){0x80, 0x10, 0x00, 0x00, sizeof(data), data}, Result, MaxResultLen, ResultLen, sw);
}

int FIDO2GetAssertion(uint8_t *params, uint8_t paramslen, uint8_t *Result, size_t MaxResultLen, size_t *ResultLen, uint16_t *sw) {
	uint8_t data[paramslen + 1];
	data[0] = fido2CmdGetAssertion;
	memcpy(&data[1], params, paramslen);
	return FIDOExchange((sAPDU){0x80, 0x10, 0x00, 0x00, sizeof(data), data}, Result, MaxResultLen, ResultLen, sw);
}

int FIDOCheckDERAndGetKey(uint8_t *der, size_t derLen, bool verbose, uint8_t *publicKey, size_t publicKeyMaxLen) {
	int res;
	
	// load CA's
	mbedtls_x509_crt cacert;
	mbedtls_x509_crt_init(&cacert);
	res = mbedtls_x509_crt_parse(&cacert, (const unsigned char *) additional_ca_pem, additional_ca_pem_len);
	if (res < 0) {
		PrintAndLog("ERROR: CA parse certificate returned -0x%x - %s", -res, ecdsa_get_error(res));
	}
	if (verbose) 
		PrintAndLog("CA load OK. %d skipped", res);
	
	// load DER certificate from authenticator's data
	mbedtls_x509_crt cert;
	mbedtls_x509_crt_init(&cert);
	res = mbedtls_x509_crt_parse_der(&cert, der, derLen);
	if (res) {
		PrintAndLog("ERROR: DER parse returned 0x%x - %s", (res<0)?-res:res, ecdsa_get_error(res));
	}
	
	// get certificate info
	char linfo[300] = {0};
	if (verbose) {
		mbedtls_x509_crt_info(linfo, sizeof(linfo), "  ", &cert);
		PrintAndLog("DER certificate info:\n%s", linfo);
	}
	
	// verify certificate
	uint32_t verifyflags = 0;
	res = mbedtls_x509_crt_verify(&cert, &cacert, NULL, NULL, &verifyflags, NULL, NULL);
	if (res) {
		PrintAndLog("ERROR: DER verify returned 0x%x - %s", (res<0)?-res:res, ecdsa_get_error(res));
	} else {
		PrintAndLog("Certificate OK.");
	}
	
	if (verbose) {
		memset(linfo, 0x00, sizeof(linfo));
		mbedtls_x509_crt_verify_info(linfo, sizeof(linfo), "  ", verifyflags);
		PrintAndLog("Verification info:\n%s", linfo);
	}
	
	// get public key
	res = ecdsa_public_key_from_pk(&cert.pk, publicKey, publicKeyMaxLen);
	if (res) {
		PrintAndLog("ERROR: getting public key from certificate 0x%x - %s", (res<0)?-res:res, ecdsa_get_error(res));
	} else {
		if (verbose)
			PrintAndLog("Got a public key from certificate:\n%s", sprint_hex_inrow(publicKey, 65));
	}

	if (verbose)
		PrintAndLog("------------------DER-------------------");

	mbedtls_x509_crt_free(&cert);
	mbedtls_x509_crt_free(&cacert);
	
	return 0;
}

#define fido_check_if(r) if ((r) != CborNoError) {return r;} else
#define fido_check(r) if ((r) != CborNoError) return r;

int CBOREncodeClientDataHash(json_t *root, CborEncoder *encoder) {
	uint8_t buf[100] = {0};
	size_t jlen;

	JsonLoadBufAsHex(root, "$.ClientDataHash", buf, sizeof(buf), &jlen);
	
	// fill with 0x00 if not found
	if (!jlen)
		jlen = 32;
	
	int res = cbor_encode_byte_string(encoder, buf, jlen);
	fido_check(res);

	return 0;
}

int CBOREncodeElm(json_t *root, char *rootElmId, CborEncoder *encoder) {
	json_t *elm = json_object_get(root, rootElmId);
	if (!elm)
		return 1;
	
	int res = JsonToCbor(elm, encoder);

	return res;
}

int FIDO2CreateMakeCredentionalReq(json_t *root, uint8_t *data, size_t maxdatalen, size_t *datalen) {
	if (datalen)
		*datalen = 0;
	if (!root || !data || !maxdatalen)
		return 1;

	int res;
	CborEncoder encoder;
	CborEncoder map;
	
	cbor_encoder_init(&encoder, data, maxdatalen, 0);

	// create main map
	res = cbor_encoder_create_map(&encoder, &map, 5);
	fido_check_if(res) {
		// clientDataHash
		res = cbor_encode_uint(&map, 1);
		fido_check_if(res) {
			res = CBOREncodeClientDataHash(root, &map);
			fido_check(res);
		}

		// rp
		res = cbor_encode_uint(&map, 2);
		fido_check_if(res) {
			res = CBOREncodeElm(root, "RelyingPartyEntity", &map);
			fido_check(res);
		}

		// user
		res = cbor_encode_uint(&map, 3);
		fido_check_if(res) {
			res = CBOREncodeElm(root, "UserEntity", &map);
			fido_check(res);
		}

		// pubKeyCredParams
		res = cbor_encode_uint(&map, 4);
		fido_check_if(res) {
			res = CBOREncodeElm(root, "pubKeyCredParams", &map);
			fido_check(res);
		}

		// options
		res = cbor_encode_uint(&map, 7);
		fido_check_if(res) {
			res = CBOREncodeElm(root, "options", &map);
			fido_check(res);
		}
	}
	res = cbor_encoder_close_container(&encoder, &map);
	fido_check(res);
	
	size_t len = cbor_encoder_get_buffer_size(&encoder, data);
	if (datalen)
		*datalen = len;
	
	return 0;
}