/**
 * xrdp: A Remote Desktop Protocol server.
 *
 * Copyright (C) Jay Sorg 2004-2014
 *
 * 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.
 *
 * ssl calls
 */

#include <stdlib.h> /* needed for openssl headers */
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/rc4.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>

#include "os_calls.h"
#include "arch.h"
#include "ssl_calls.h"

#if defined(OPENSSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER >= 0x0090800f)
#undef OLD_RSA_GEN1
#else
#define OLD_RSA_GEN1
#endif

/*****************************************************************************/
int
ssl_init(void)
{
    SSL_load_error_strings();
    SSL_library_init();
    return 0;
}

/*****************************************************************************/
int
ssl_finish(void)
{
    return 0;
}

/* rc4 stuff */

/*****************************************************************************/
void *APP_CC
ssl_rc4_info_create(void)
{
    return g_malloc(sizeof(RC4_KEY), 1);
}

/*****************************************************************************/
void APP_CC
ssl_rc4_info_delete(void *rc4_info)
{
    g_free(rc4_info);
}

/*****************************************************************************/
void APP_CC
ssl_rc4_set_key(void *rc4_info, char *key, int len)
{
    RC4_set_key((RC4_KEY *)rc4_info, len, (tui8 *)key);
}

/*****************************************************************************/
void APP_CC
ssl_rc4_crypt(void *rc4_info, char *data, int len)
{
    RC4((RC4_KEY *)rc4_info, len, (tui8 *)data, (tui8 *)data);
}

/* sha1 stuff */

/*****************************************************************************/
void *APP_CC
ssl_sha1_info_create(void)
{
    return g_malloc(sizeof(SHA_CTX), 1);
}

/*****************************************************************************/
void APP_CC
ssl_sha1_info_delete(void *sha1_info)
{
    g_free(sha1_info);
}

/*****************************************************************************/
void APP_CC
ssl_sha1_clear(void *sha1_info)
{
    SHA1_Init((SHA_CTX *)sha1_info);
}

/*****************************************************************************/
void APP_CC
ssl_sha1_transform(void *sha1_info, char *data, int len)
{
    SHA1_Update((SHA_CTX *)sha1_info, data, len);
}

/*****************************************************************************/
void APP_CC
ssl_sha1_complete(void *sha1_info, char *data)
{
    SHA1_Final((tui8 *)data, (SHA_CTX *)sha1_info);
}

/* md5 stuff */

/*****************************************************************************/
void *APP_CC
ssl_md5_info_create(void)
{
    return g_malloc(sizeof(MD5_CTX), 1);
}

/*****************************************************************************/
void APP_CC
ssl_md5_info_delete(void *md5_info)
{
    g_free(md5_info);
}

/*****************************************************************************/
void APP_CC
ssl_md5_clear(void *md5_info)
{
    MD5_Init((MD5_CTX *)md5_info);
}

/*****************************************************************************/
void APP_CC
ssl_md5_transform(void *md5_info, char *data, int len)
{
    MD5_Update((MD5_CTX *)md5_info, data, len);
}

/*****************************************************************************/
void APP_CC
ssl_md5_complete(void *md5_info, char *data)
{
    MD5_Final((tui8 *)data, (MD5_CTX *)md5_info);
}

/*****************************************************************************/
void *APP_CC
ssl_des3_encrypt_info_create(const char *key, const char* ivec)
{
    EVP_CIPHER_CTX *des3_ctx;
    const tui8 *lkey;
    const tui8 *livec;

    des3_ctx = (EVP_CIPHER_CTX *) g_malloc(sizeof(EVP_CIPHER_CTX), 1);
    EVP_CIPHER_CTX_init(des3_ctx);
    lkey = (const tui8 *) key;
    livec = (const tui8 *) ivec;
    EVP_EncryptInit_ex(des3_ctx, EVP_des_ede3_cbc(), NULL, lkey, livec);
    EVP_CIPHER_CTX_set_padding(des3_ctx, 0);
    return des3_ctx;
}

/*****************************************************************************/
void *APP_CC
ssl_des3_decrypt_info_create(const char *key, const char* ivec)
{
    EVP_CIPHER_CTX *des3_ctx;
    const tui8 *lkey;
    const tui8 *livec;

    des3_ctx = g_malloc(sizeof(EVP_CIPHER_CTX), 1);
    EVP_CIPHER_CTX_init(des3_ctx);
    lkey = (const tui8 *) key;
    livec = (const tui8 *) ivec;
    EVP_DecryptInit_ex(des3_ctx, EVP_des_ede3_cbc(), NULL, lkey, livec);
    EVP_CIPHER_CTX_set_padding(des3_ctx, 0);
    return des3_ctx;
}

/*****************************************************************************/
void APP_CC
ssl_des3_info_delete(void *des3)
{
    EVP_CIPHER_CTX *des3_ctx;

    des3_ctx = (EVP_CIPHER_CTX *) des3;
    if (des3_ctx != 0)
    {
        EVP_CIPHER_CTX_cleanup(des3_ctx);
    }
}

/*****************************************************************************/
int APP_CC
ssl_des3_encrypt(void *des3, int length, const char *in_data, char *out_data)
{
    EVP_CIPHER_CTX *des3_ctx;
    int len;
    const tui8 *lin_data;
    tui8 *lout_data;

    des3_ctx = (EVP_CIPHER_CTX *) des3;
    lin_data = (const tui8 *) in_data;
    lout_data = (tui8 *) out_data;
    EVP_EncryptUpdate(des3_ctx, lout_data, &len, lin_data, length);
    return 0;
}

/*****************************************************************************/
int APP_CC
ssl_des3_decrypt(void *des3, int length, const char *in_data, char *out_data)
{
    EVP_CIPHER_CTX *des3_ctx;
    int len;
    const tui8 *lin_data;
    tui8 *lout_data;

    des3_ctx = (EVP_CIPHER_CTX *) des3;
    lin_data = (const tui8 *) in_data;
    lout_data = (tui8 *) out_data;
    EVP_DecryptUpdate(des3_ctx, lout_data, &len, lin_data, length);
    return 0;
}

/*****************************************************************************/
static void APP_CC
ssl_reverse_it(char *p, int len)
{
    int i;
    int j;
    char temp;

    i = 0;
    j = len - 1;

    while (i < j)
    {
        temp = p[i];
        p[i] = p[j];
        p[j] = temp;
        i++;
        j--;
    }
}

/*****************************************************************************/
int APP_CC
ssl_mod_exp(char *out, int out_len, char *in, int in_len,
            char *mod, int mod_len, char *exp, int exp_len)
{
    BN_CTX *ctx;
    BIGNUM lmod;
    BIGNUM lexp;
    BIGNUM lin;
    BIGNUM lout;
    int rv;
    char *l_out;
    char *l_in;
    char *l_mod;
    char *l_exp;

    l_out = (char *)g_malloc(out_len, 1);
    l_in = (char *)g_malloc(in_len, 1);
    l_mod = (char *)g_malloc(mod_len, 1);
    l_exp = (char *)g_malloc(exp_len, 1);
    g_memcpy(l_in, in, in_len);
    g_memcpy(l_mod, mod, mod_len);
    g_memcpy(l_exp, exp, exp_len);
    ssl_reverse_it(l_in, in_len);
    ssl_reverse_it(l_mod, mod_len);
    ssl_reverse_it(l_exp, exp_len);
    ctx = BN_CTX_new();
    BN_init(&lmod);
    BN_init(&lexp);
    BN_init(&lin);
    BN_init(&lout);
    BN_bin2bn((tui8 *)l_mod, mod_len, &lmod);
    BN_bin2bn((tui8 *)l_exp, exp_len, &lexp);
    BN_bin2bn((tui8 *)l_in, in_len, &lin);
    BN_mod_exp(&lout, &lin, &lexp, &lmod, ctx);
    rv = BN_bn2bin(&lout, (tui8 *)l_out);

    if (rv <= out_len)
    {
        ssl_reverse_it(l_out, rv);
        g_memcpy(out, l_out, out_len);
    }
    else
    {
        rv = 0;
    }

    BN_free(&lin);
    BN_free(&lout);
    BN_free(&lexp);
    BN_free(&lmod);
    BN_CTX_free(ctx);
    g_free(l_out);
    g_free(l_in);
    g_free(l_mod);
    g_free(l_exp);
    return rv;
}

#if defined(OLD_RSA_GEN1)
/*****************************************************************************/
/* returns error
   generates a new rsa key
   exp is passed in and mod and pri are passed out */
int APP_CC
ssl_gen_key_xrdp1(int key_size_in_bits, char *exp, int exp_len,
                  char *mod, int mod_len, char *pri, int pri_len)
{
    int my_e;
    RSA *my_key;
    char *lmod;
    char *lpri;
    tui8 *lexp;
    int error;
    int len;

    if ((exp_len != 4) || (mod_len != 64) || (pri_len != 64))
    {
        return 1;
    }

    lmod = (char *)g_malloc(mod_len, 0);
    lpri = (char *)g_malloc(pri_len, 0);
    lexp = (tui8 *)exp;
    my_e = lexp[0];
    my_e |= lexp[1] << 8;
    my_e |= lexp[2] << 16;
    my_e |= lexp[3] << 24;
    /* srand is in stdlib.h */
    srand(g_time1());
    my_key = RSA_generate_key(key_size_in_bits, my_e, 0, 0);
    error = my_key == 0;

    if (error == 0)
    {
        len = BN_num_bytes(my_key->n);
        error = len != mod_len;
    }

    if (error == 0)
    {
        BN_bn2bin(my_key->n, (tui8 *)lmod);
        ssl_reverse_it(lmod, mod_len);
    }

    if (error == 0)
    {
        len = BN_num_bytes(my_key->d);
        error = len != pri_len;
    }

    if (error == 0)
    {
        BN_bn2bin(my_key->d, (tui8 *)lpri);
        ssl_reverse_it(lpri, pri_len);
    }

    if (error == 0)
    {
        g_memcpy(mod, lmod, mod_len);
        g_memcpy(pri, lpri, pri_len);
    }

    RSA_free(my_key);
    g_free(lmod);
    g_free(lpri);
    return error;
}
#else
/*****************************************************************************/
/* returns error
   generates a new rsa key
   exp is passed in and mod and pri are passed out */
int APP_CC
ssl_gen_key_xrdp1(int key_size_in_bits, char *exp, int exp_len,
                  char *mod, int mod_len, char *pri, int pri_len)
{
    BIGNUM *my_e;
    RSA *my_key;
    char *lexp;
    char *lmod;
    char *lpri;
    int error;
    int len;

    if ((exp_len != 4) || (mod_len != 64) || (pri_len != 64))
    {
        return 1;
    }

    lexp = (char *)g_malloc(exp_len, 0);
    lmod = (char *)g_malloc(mod_len, 0);
    lpri = (char *)g_malloc(pri_len, 0);
    g_memcpy(lexp, exp, exp_len);
    ssl_reverse_it(lexp, exp_len);
    my_e = BN_new();
    BN_bin2bn((tui8 *)lexp, exp_len, my_e);
    my_key = RSA_new();
    error = RSA_generate_key_ex(my_key, key_size_in_bits, my_e, 0) == 0;

    if (error == 0)
    {
        len = BN_num_bytes(my_key->n);
        error = len != mod_len;
    }

    if (error == 0)
    {
        BN_bn2bin(my_key->n, (tui8 *)lmod);
        ssl_reverse_it(lmod, mod_len);
    }

    if (error == 0)
    {
        len = BN_num_bytes(my_key->d);
        error = len != pri_len;
    }

    if (error == 0)
    {
        BN_bn2bin(my_key->d, (tui8 *)lpri);
        ssl_reverse_it(lpri, pri_len);
    }

    if (error == 0)
    {
        g_memcpy(mod, lmod, mod_len);
        g_memcpy(pri, lpri, pri_len);
    }

    BN_free(my_e);
    RSA_free(my_key);
    g_free(lexp);
    g_free(lmod);
    g_free(lpri);
    return error;
}
#endif