/* 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>

#ifndef EVP_MAX_BLOCK_LENGTH
#define EVP_MAX_BLOCK_LENGTH 32
#endif

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);
    BN_clear_free(dsasig.s);
    BN_clear_free(dsasig.r);

    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;
}