/**
 * FreeRDP: A Remote Desktop Protocol Client
 * Cryptographic Abstraction Layer
 *
 * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
 *
 * 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.
 */

#include "crypto.h"

CryptoSha1 crypto_sha1_init(void)
{
	CryptoSha1 sha1 = xmalloc(sizeof(*sha1));
	SHA1_Init(&sha1->sha_ctx);
	return sha1;
}

void crypto_sha1_update(CryptoSha1 sha1, uint8* data, uint32 length)
{
	SHA1_Update(&sha1->sha_ctx, data, length);
}

void crypto_sha1_final(CryptoSha1 sha1, uint8* out_data)
{
	SHA1_Final(out_data, &sha1->sha_ctx);
	xfree(sha1);
}

CryptoMd5 crypto_md5_init(void)
{
	CryptoMd5 md5 = xmalloc(sizeof(*md5));
	MD5_Init(&md5->md5_ctx);
	return md5;
}

void crypto_md5_update(CryptoMd5 md5, uint8* data, uint32 length)
{
	MD5_Update(&md5->md5_ctx, data, length);
}

void crypto_md5_final(CryptoMd5 md5, uint8* out_data)
{
	MD5_Final(out_data, &md5->md5_ctx);
	xfree(md5);
}

CryptoRc4 crypto_rc4_init(uint8* key, uint32 length)
{
	CryptoRc4 rc4 = xmalloc(sizeof(*rc4));
	RC4_set_key(&rc4->rc4_key, length, key);
	return rc4;
}

void crypto_rc4(CryptoRc4 rc4, uint32 length, uint8* in_data, uint8* out_data)
{
	RC4(&rc4->rc4_key, length, in_data, out_data);
}

void crypto_rc4_free(CryptoRc4 rc4)
{
	xfree(rc4);
}

CryptoCert crypto_cert_read(uint8* data, uint32 length)
{
	CryptoCert cert = xmalloc(sizeof(*cert));
	/* this will move the data pointer but we don't care, we don't use it again */
	cert->px509 = d2i_X509(NULL, (D2I_X509_CONST unsigned char **) &data, length);
	return cert;
}

void crypto_cert_free(CryptoCert cert)
{
	X509_free(cert->px509);
	xfree(cert);
}

boolean crypto_cert_verify(CryptoCert server_cert, CryptoCert cacert)
{
	return True; /* FIXME: do the actual verification */
}

boolean crypto_cert_get_public_key(CryptoCert cert, rdpBlob* public_key)
{
	uint8* p;
	int length;
	boolean status = True;
	EVP_PKEY* pkey = NULL;

	pkey = X509_get_pubkey(cert->px509);

	if (!pkey)
	{
		printf("crypto_cert_get_public_key: X509_get_pubkey() failed\n");
		status = False;
		goto exit;
	}

	length = i2d_PublicKey(pkey, NULL);

	if (length < 1)
	{
		printf("crypto_cert_get_public_key: i2d_PublicKey() failed\n");
		status = False;
		goto exit;
	}

	freerdp_blob_alloc(public_key, length);
	p = (unsigned char*) public_key->data;
	i2d_PublicKey(pkey, &p);

exit:
	if (pkey)
		EVP_PKEY_free(pkey);

	return status;
}

void crypto_rsa_encrypt(uint8* input, int length, uint32 key_length, uint8* modulus, uint8* exponent, uint8* output)
{
	BN_CTX *ctx;
	int output_length;
	uint8* input_reverse;
	uint8* modulus_reverse;
	uint8* exponent_reverse;
	BIGNUM mod, exp, x, y;

	input_reverse = (uint8*) xmalloc(2 * MODULUS_MAX_SIZE + EXPONENT_MAX_SIZE);
	modulus_reverse = input_reverse + MODULUS_MAX_SIZE;
	exponent_reverse = modulus_reverse + MODULUS_MAX_SIZE;

	memcpy(modulus_reverse, modulus, key_length);
	crypto_reverse(modulus_reverse, key_length);
	memcpy(exponent_reverse, exponent, EXPONENT_MAX_SIZE);
	crypto_reverse(exponent_reverse, EXPONENT_MAX_SIZE);
	memcpy(input_reverse, input, length);
	crypto_reverse(input_reverse, length);

	ctx = BN_CTX_new();
	BN_init(&mod);
	BN_init(&exp);
	BN_init(&x);
	BN_init(&y);

	BN_bin2bn(modulus_reverse, key_length, &mod);
	BN_bin2bn(exponent_reverse, EXPONENT_MAX_SIZE, &exp);
	BN_bin2bn(input_reverse, length, &x);
	BN_mod_exp(&y, &x, &exp, &mod, ctx);

	output_length = BN_bn2bin(&y, output);
	crypto_reverse(output, output_length);

	if (output_length < (int) key_length)
		memset(output + output_length, 0, key_length - output_length);

	BN_free(&y);
	BN_clear_free(&x);
	BN_free(&exp);
	BN_free(&mod);
	BN_CTX_free(ctx);
	xfree(input_reverse);
}

void crypto_reverse(uint8* data, int length)
{
	int i, j;
	uint8 temp;

	for (i = 0, j = length - 1; i < j; i++, j--)
	{
		temp = data[i];
		data[i] = data[j];
		data[j] = temp;
	}
}

void crypto_nonce(uint8* nonce, int size)
{
	RAND_bytes((void*) nonce, size);
}

char* crypto_cert_fingerprint(X509* xcert)
{
	char* p;
	int i = 0;
	char* fp_buffer;
	unsigned int fp_len;
	unsigned char fp[EVP_MAX_MD_SIZE];

	X509_digest(xcert, EVP_sha1(), fp, &fp_len);

	fp_buffer = xzalloc(3 * fp_len);
	p = fp_buffer;

	for (i = 0; i < fp_len - 1; i++)
	{
		sprintf(p, "%02x:", fp[i]);
		p = (char*) &fp_buffer[i * 3];
	}
	sprintf(p, "%02x", fp[i]);

	return fp_buffer;
}

boolean x509_verify_cert(CryptoCert cert)
{
	char* cert_loc;
	X509_STORE_CTX* csc;
	boolean status = False;
	X509_STORE* cert_ctx = NULL;
	X509_LOOKUP* lookup = NULL;
	X509* xcert = cert->px509;

	cert_ctx = X509_STORE_new();

	if (cert_ctx == NULL)
		goto end;

	OpenSSL_add_all_algorithms();
	lookup = X509_STORE_add_lookup(cert_ctx, X509_LOOKUP_file());

	if (lookup == NULL)
		goto end;

	lookup = X509_STORE_add_lookup(cert_ctx, X509_LOOKUP_hash_dir());

	if (lookup == NULL)
		goto end;

	X509_LOOKUP_add_dir(lookup, NULL, X509_FILETYPE_DEFAULT);
	cert_loc = get_local_certloc();

	if(cert_loc != NULL)
	{
		X509_LOOKUP_add_dir(lookup, cert_loc, X509_FILETYPE_ASN1);
		xfree(cert_loc);
	}

	csc = X509_STORE_CTX_new();

	if (csc == NULL)
		goto end;

	X509_STORE_set_flags(cert_ctx, 0);

	if(!X509_STORE_CTX_init(csc, cert_ctx, xcert, 0))
		goto end;

	if (X509_verify_cert(csc) == 1)
		status = True;

	X509_STORE_CTX_free(csc);
	X509_STORE_free(cert_ctx);

end:
	return status;
}

rdpCertdata* crypto_get_certdata(X509* xcert, char* hostname)
{
	char* fp;
	rdpCertdata* certdata;

	fp = crypto_cert_fingerprint(xcert);
	certdata = certdata_new(hostname, fp);
	xfree(fp);

	return certdata;
}

void crypto_cert_printinfo(X509* xcert)
{
	char* fp;
	char* issuer;
	char* subject;

	subject = X509_NAME_oneline(X509_get_subject_name(xcert), NULL, 0);
	issuer = X509_NAME_oneline(X509_get_issuer_name(xcert), NULL, 0);
	fp = crypto_cert_fingerprint(xcert);

	printf("Certificate details:\n");
	printf("\tSubject: %s\n", subject);
	printf("\tIssuer: %s\n", issuer);
	printf("\tThumbprint: %s\n", fp);
	printf("The above X.509 certificate could not be verified, possibly because you do not have "
			"the CA certificate in your certificate store, or the certificate has expired."
			"Please look at the documentation on how to create local certificate store for a private CA.\n");

	xfree(fp);
}