/* Copyright (C) 2006, 2007 The Written Word, Inc.  All rights reserved.
 * Author: Simon Josefsson
 * Copyright (c) 2004-2006, Sara Golemon <sarag@libssh2.org>
 *
 * Redistribution and use in source and binary forms,
 * with or without modification, are permitted provided
 * that the following conditions are met:
 *
 *   Redistributions of source code must retain the above
 *   copyright notice, this list of conditions and the
 *   following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 *   Neither the name of the copyright holder nor the names
 *   of any other contributors may be used to endorse or
 *   promote products derived from this software without
 *   specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */

#include "libssh2_priv.h"
#include <string.h>

int _libssh2_rsa_new(libssh2_rsa_ctx **rsa,
		     const unsigned char *edata,
		     unsigned long elen,
		     const unsigned char *ndata,
		     unsigned long nlen,
		     const unsigned char *ddata,
		     unsigned long dlen,
		     const unsigned char *pdata,
		     unsigned long plen,
		     const unsigned char *qdata,
		     unsigned long qlen,
		     const unsigned char *e1data,
		     unsigned long e1len,
		     const unsigned char *e2data,
		     unsigned long e2len,
		     const unsigned char *coeffdata,
		     unsigned long coefflen)
{
	*rsa = RSA_new();

	(*rsa)->e = BN_new();
	BN_bin2bn(edata, elen, (*rsa)->e);

	(*rsa)->n = BN_new();
	BN_bin2bn(ndata, nlen, (*rsa)->n);

	if (ddata)
	  {
	    (*rsa)->d = BN_new();
	    BN_bin2bn(ddata, dlen, (*rsa)->d);

	    (*rsa)->p = BN_new();
	    BN_bin2bn(pdata, plen, (*rsa)->p);

	    (*rsa)->q = BN_new();
	    BN_bin2bn(qdata, qlen, (*rsa)->q);

	    (*rsa)->dmp1 = BN_new();
	    BN_bin2bn(e1data, e1len, (*rsa)->dmp1);

	    (*rsa)->dmq1 = BN_new();
	    BN_bin2bn(e2data, e2len, (*rsa)->dmq1);

	    (*rsa)->iqmp = BN_new();
	    BN_bin2bn(coeffdata, coefflen, (*rsa)->iqmp);
	  }
	return 0;
}

int _libssh2_rsa_sha1_verify(libssh2_rsa_ctx *rsactx,
			     const unsigned char *sig,
			     unsigned long sig_len,
			     const unsigned char *m,
			     unsigned long m_len)
{
	unsigned char hash[SHA_DIGEST_LENGTH];
	int ret;

	SHA1(m, m_len, hash);
	ret = RSA_verify(NID_sha1, hash, SHA_DIGEST_LENGTH,
			 (unsigned char *)sig, sig_len, rsactx);
	return (ret == 1) ? 0 : -1;
}

int _libssh2_dsa_new(libssh2_dsa_ctx **dsactx,
		     const unsigned char *p,
		     unsigned long p_len,
		     const unsigned char *q,
		     unsigned long q_len,
		     const unsigned char *g,
		     unsigned long g_len,
		     const unsigned char *y,
		     unsigned long y_len,
		     const unsigned char *x,
		     unsigned long x_len)
{
	*dsactx = DSA_new();

	(*dsactx)->p = BN_new();
	BN_bin2bn(p, p_len, (*dsactx)->p);

	(*dsactx)->q = BN_new();
	BN_bin2bn(q, q_len, (*dsactx)->q);

	(*dsactx)->g = BN_new();
	BN_bin2bn(g, g_len, (*dsactx)->g);

	(*dsactx)->pub_key = BN_new();
	BN_bin2bn(y, y_len, (*dsactx)->pub_key);

	if (x_len) {
		(*dsactx)->priv_key = BN_new();
		BN_bin2bn(x, x_len, (*dsactx)->priv_key);
	}

	return 0;
}

int _libssh2_dsa_sha1_verify(libssh2_dsa_ctx *dsactx,
			     const unsigned char *sig,
			     const unsigned char *m,
			     unsigned long m_len)
{
	unsigned char hash[SHA_DIGEST_LENGTH];
	DSA_SIG dsasig;
	int ret;

	dsasig.r = BN_new();
	BN_bin2bn(sig, 20, dsasig.r);
	dsasig.s = BN_new();
	BN_bin2bn(sig + 20, 20, dsasig.s);

	libssh2_sha1(m, m_len, hash);
	ret = DSA_do_verify(hash, SHA_DIGEST_LENGTH, &dsasig, dsactx);

	return (ret == 1) ? 0 : -1;
}

int _libssh2_cipher_init (_libssh2_cipher_ctx *h,
			  _libssh2_cipher_type(algo),
			  unsigned char *iv,
			  unsigned char *secret,
			  int encrypt)
{
	EVP_CIPHER_CTX_init(h);
	EVP_CipherInit(h, algo(), secret, iv, encrypt);
	return 0;
}

int _libssh2_cipher_crypt(_libssh2_cipher_ctx *ctx,
			  _libssh2_cipher_type(algo),
			  int encrypt,
			  unsigned char *block)
{
	int blocksize = ctx->cipher->block_size;
	unsigned char buf[EVP_MAX_BLOCK_LENGTH];
	int ret;
	(void)algo;
	(void)encrypt;

	if (blocksize == 1) {
/* Hack for arcfour. */
		blocksize = 8;
	}
	ret = EVP_Cipher(ctx, buf, block, blocksize);
	if (ret == 1) {
		memcpy(block, buf, blocksize);
	}
	return ret == 1 ? 0 : 1;
}

/* TODO: Optionally call a passphrase callback specified by the
 * calling program
 */
static int
passphrase_cb(char *buf, int size,
	      int rwflag, char *passphrase)
{
	int passphrase_len = strlen(passphrase);
	(void)rwflag;

	if (passphrase_len > (size - 1)) {
		passphrase_len = size - 1;
	}
	memcpy(buf, passphrase, passphrase_len);
	buf[passphrase_len] = '\0';

	return passphrase_len;
}

int _libssh2_rsa_new_private (libssh2_rsa_ctx **rsa,
			      LIBSSH2_SESSION *session,
			      FILE *fp,
			      unsigned const char *passphrase)
{
	(void)session;
	if (!EVP_get_cipherbyname("des")) {
/* If this cipher isn't loaded it's a pretty good indication that none are.
 * I have *NO DOUBT* that there's a better way to deal with this ($#&%#$(%$#(
 * Someone buy me an OpenSSL manual and I'll read up on it.
 */
		OpenSSL_add_all_ciphers();
	}
	*rsa = PEM_read_RSAPrivateKey(fp, NULL, (void*)passphrase_cb,
				      (void*)passphrase);
	if (!*rsa) {
		return -1;
	}
	return 0;
}

int _libssh2_dsa_new_private (libssh2_dsa_ctx **dsa,
			      LIBSSH2_SESSION *session,
			      FILE *fp,
			      unsigned const char *passphrase)
{
	(void)session;
	if (!EVP_get_cipherbyname("des")) {
/* If this cipher isn't loaded it's a pretty good indication that none are.
 * I have *NO DOUBT* that there's a better way to deal with this ($#&%#$(%$#(
 * Someone buy me an OpenSSL manual and I'll read up on it.
 */
		OpenSSL_add_all_ciphers();
	}
	*dsa = PEM_read_DSAPrivateKey(fp, NULL, (void*)passphrase_cb,
				      (void*)passphrase);
	if (!*dsa) {
		return -1;
	}
	return 0;
}

int _libssh2_rsa_sha1_sign(LIBSSH2_SESSION *session,
			   libssh2_rsa_ctx *rsactx,
			   const unsigned char *hash,
			   unsigned long hash_len,
			   unsigned char **signature,
			   unsigned long *signature_len)
{
	int ret;
	unsigned char *sig;
	unsigned int sig_len;

	sig_len = RSA_size(rsactx);
	sig = LIBSSH2_ALLOC(session, sig_len);

	if (!sig) {
		return -1;
	}

	ret = RSA_sign(NID_sha1, hash, hash_len, sig, &sig_len, rsactx);

	if (!ret) {
		LIBSSH2_FREE(session, sig);
		return -1;
	}

	*signature = sig;
	*signature_len = sig_len;

	return 0;
}

int _libssh2_dsa_sha1_sign(libssh2_dsa_ctx *dsactx,
			   const unsigned char *hash,
			   unsigned long hash_len,
			   unsigned char *signature)
{
	DSA_SIG *sig;
	int r_len, s_len, rs_pad;
	(void)hash_len;

	sig = DSA_do_sign(hash, SHA_DIGEST_LENGTH, dsactx);
	if (!sig) {
		return -1;
	}

	r_len = BN_num_bytes(sig->r);
	s_len = BN_num_bytes(sig->s);
	rs_pad = (2 * SHA_DIGEST_LENGTH) - (r_len + s_len);
	if (rs_pad < 0) {
		DSA_SIG_free(sig);
		return -1;
	}

	BN_bn2bin(sig->r, signature + rs_pad);
	BN_bn2bin(sig->s, signature + rs_pad + r_len);

	DSA_SIG_free(sig);

	return 0;
}