/* crypto/engine/hw_cswift.c */
/*
 * Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL project
 * 2000.
 */
/* ====================================================================
 * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/buffer.h>
#include <openssl/dso.h>
#include <openssl/engine.h>
#ifndef OPENSSL_NO_RSA
# include <openssl/rsa.h>
#endif
#ifndef OPENSSL_NO_DSA
# include <openssl/dsa.h>
#endif
#ifndef OPENSSL_NO_DH
# include <openssl/dh.h>
#endif
#include <openssl/rand.h>
#include <openssl/bn.h>

#ifndef OPENSSL_NO_HW
# ifndef OPENSSL_NO_HW_CSWIFT

/*
 * Attribution notice: Rainbow have generously allowed me to reproduce the
 * necessary definitions here from their API. This means the support can
 * build independently of whether application builders have the API or
 * hardware. This will allow developers to easily produce software that has
 * latent hardware support for any users that have accelerators installed,
 * without the developers themselves needing anything extra. I have only
 * clipped the parts from the CryptoSwift header files that are (or seem)
 * relevant to the CryptoSwift support code. This is simply to keep the file
 * sizes reasonable. [Geoff]
 */
#  ifdef FLAT_INC
#   include "cswift.h"
#  else
#   include "vendor_defns/cswift.h"
#  endif

#  define CSWIFT_LIB_NAME "cswift engine"
#  include "e_cswift_err.c"

#  define DECIMAL_SIZE(type)      ((sizeof(type)*8+2)/3+1)

static int cswift_destroy(ENGINE *e);
static int cswift_init(ENGINE *e);
static int cswift_finish(ENGINE *e);
static int cswift_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void));
#  ifndef OPENSSL_NO_RSA
static int cswift_bn_32copy(SW_LARGENUMBER *out, const BIGNUM *in);
#  endif

/* BIGNUM stuff */
static int cswift_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                          const BIGNUM *m, BN_CTX *ctx);
#  ifndef OPENSSL_NO_RSA
static int cswift_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                              const BIGNUM *q, const BIGNUM *dmp1,
                              const BIGNUM *dmq1, const BIGNUM *iqmp,
                              BN_CTX *ctx);
#  endif

#  ifndef OPENSSL_NO_RSA
/* RSA stuff */
static int cswift_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
                              BN_CTX *ctx);
/* This function is aliased to mod_exp (with the mont stuff dropped). */
static int cswift_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                               const BIGNUM *m, BN_CTX *ctx,
                               BN_MONT_CTX *m_ctx);
#  endif

#  ifndef OPENSSL_NO_DSA
/* DSA stuff */
static DSA_SIG *cswift_dsa_sign(const unsigned char *dgst, int dlen,
                                DSA *dsa);
static int cswift_dsa_verify(const unsigned char *dgst, int dgst_len,
                             DSA_SIG *sig, DSA *dsa);
#  endif

#  ifndef OPENSSL_NO_DH
/* DH stuff */
/* This function is alised to mod_exp (with the DH and mont dropped). */
static int cswift_mod_exp_dh(const DH *dh, BIGNUM *r,
                             const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *m, BN_CTX *ctx,
                             BN_MONT_CTX *m_ctx);
#  endif

/* RAND stuff */
static int cswift_rand_bytes(unsigned char *buf, int num);
static int cswift_rand_status(void);

/* The definitions for control commands specific to this engine */
#  define CSWIFT_CMD_SO_PATH              ENGINE_CMD_BASE
static const ENGINE_CMD_DEFN cswift_cmd_defns[] = {
    {CSWIFT_CMD_SO_PATH,
     "SO_PATH",
     "Specifies the path to the 'cswift' shared library",
     ENGINE_CMD_FLAG_STRING},
    {0, NULL, NULL, 0}
};

#  ifndef OPENSSL_NO_RSA
/* Our internal RSA_METHOD that we provide pointers to */
static RSA_METHOD cswift_rsa = {
    "CryptoSwift RSA method",
    NULL,
    NULL,
    NULL,
    NULL,
    cswift_rsa_mod_exp,
    cswift_mod_exp_mont,
    NULL,
    NULL,
    0,
    NULL,
    NULL,
    NULL,
    NULL
};
#  endif

#  ifndef OPENSSL_NO_DSA
/* Our internal DSA_METHOD that we provide pointers to */
static DSA_METHOD cswift_dsa = {
    "CryptoSwift DSA method",
    cswift_dsa_sign,
    NULL,                       /* dsa_sign_setup */
    cswift_dsa_verify,
    NULL,                       /* dsa_mod_exp */
    NULL,                       /* bn_mod_exp */
    NULL,                       /* init */
    NULL,                       /* finish */
    0,                          /* flags */
    NULL,                       /* app_data */
    NULL,                       /* dsa_paramgen */
    NULL                        /* dsa_keygen */
};
#  endif

#  ifndef OPENSSL_NO_DH
/* Our internal DH_METHOD that we provide pointers to */
static DH_METHOD cswift_dh = {
    "CryptoSwift DH method",
    NULL,
    NULL,
    cswift_mod_exp_dh,
    NULL,
    NULL,
    0,
    NULL,
    NULL
};
#  endif

static RAND_METHOD cswift_random = {
    /* "CryptoSwift RAND method", */
    NULL,
    cswift_rand_bytes,
    NULL,
    NULL,
    cswift_rand_bytes,
    cswift_rand_status,
};

/* Constants used when creating the ENGINE */
static const char *engine_cswift_id = "cswift";
static const char *engine_cswift_name = "CryptoSwift hardware engine support";

/*
 * This internal function is used by ENGINE_cswift() and possibly by the
 * "dynamic" ENGINE support too
 */
static int bind_helper(ENGINE *e)
{
#  ifndef OPENSSL_NO_RSA
    const RSA_METHOD *meth1;
#  endif
#  ifndef OPENSSL_NO_DH
    const DH_METHOD *meth2;
#  endif
    if (!ENGINE_set_id(e, engine_cswift_id) ||
        !ENGINE_set_name(e, engine_cswift_name) ||
#  ifndef OPENSSL_NO_RSA
        !ENGINE_set_RSA(e, &cswift_rsa) ||
#  endif
#  ifndef OPENSSL_NO_DSA
        !ENGINE_set_DSA(e, &cswift_dsa) ||
#  endif
#  ifndef OPENSSL_NO_DH
        !ENGINE_set_DH(e, &cswift_dh) ||
#  endif
        !ENGINE_set_RAND(e, &cswift_random) ||
        !ENGINE_set_destroy_function(e, cswift_destroy) ||
        !ENGINE_set_init_function(e, cswift_init) ||
        !ENGINE_set_finish_function(e, cswift_finish) ||
        !ENGINE_set_ctrl_function(e, cswift_ctrl) ||
        !ENGINE_set_cmd_defns(e, cswift_cmd_defns))
        return 0;

#  ifndef OPENSSL_NO_RSA
    /*
     * We know that the "PKCS1_SSLeay()" functions hook properly to the
     * cswift-specific mod_exp and mod_exp_crt so we use those functions. NB:
     * We don't use ENGINE_openssl() or anything "more generic" because
     * something like the RSAref code may not hook properly, and if you own
     * one of these cards then you have the right to do RSA operations on it
     * anyway!
     */
    meth1 = RSA_PKCS1_SSLeay();
    cswift_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
    cswift_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
    cswift_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
    cswift_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
#  endif

#  ifndef OPENSSL_NO_DH
    /* Much the same for Diffie-Hellman */
    meth2 = DH_OpenSSL();
    cswift_dh.generate_key = meth2->generate_key;
    cswift_dh.compute_key = meth2->compute_key;
#  endif

    /* Ensure the cswift error handling is set up */
    ERR_load_CSWIFT_strings();
    return 1;
}

#  ifdef OPENSSL_NO_DYNAMIC_ENGINE
static ENGINE *engine_cswift(void)
{
    ENGINE *ret = ENGINE_new();
    if (!ret)
        return NULL;
    if (!bind_helper(ret)) {
        ENGINE_free(ret);
        return NULL;
    }
    return ret;
}

void ENGINE_load_cswift(void)
{
    /* Copied from eng_[openssl|dyn].c */
    ENGINE *toadd = engine_cswift();
    if (!toadd)
        return;
    ENGINE_add(toadd);
    ENGINE_free(toadd);
    ERR_clear_error();
}
#  endif

/*
 * This is a process-global DSO handle used for loading and unloading the
 * CryptoSwift library. NB: This is only set (or unset) during an init() or
 * finish() call (reference counts permitting) and they're operating with
 * global locks, so this should be thread-safe implicitly.
 */
static DSO *cswift_dso = NULL;

/*
 * These are the function pointers that are (un)set when the library has
 * successfully (un)loaded.
 */
t_swAcquireAccContext *p_CSwift_AcquireAccContext = NULL;
t_swAttachKeyParam *p_CSwift_AttachKeyParam = NULL;
t_swSimpleRequest *p_CSwift_SimpleRequest = NULL;
t_swReleaseAccContext *p_CSwift_ReleaseAccContext = NULL;

/* Used in the DSO operations. */
static const char *CSWIFT_LIBNAME = NULL;
static const char *get_CSWIFT_LIBNAME(void)
{
    if (CSWIFT_LIBNAME)
        return CSWIFT_LIBNAME;
    return "swift";
}

static void free_CSWIFT_LIBNAME(void)
{
    if (CSWIFT_LIBNAME)
        OPENSSL_free((void *)CSWIFT_LIBNAME);
    CSWIFT_LIBNAME = NULL;
}

static long set_CSWIFT_LIBNAME(const char *name)
{
    free_CSWIFT_LIBNAME();
    return (((CSWIFT_LIBNAME = BUF_strdup(name)) != NULL) ? 1 : 0);
}

static const char *CSWIFT_F1 = "swAcquireAccContext";
static const char *CSWIFT_F2 = "swAttachKeyParam";
static const char *CSWIFT_F3 = "swSimpleRequest";
static const char *CSWIFT_F4 = "swReleaseAccContext";

/*
 * CryptoSwift library functions and mechanics - these are used by the
 * higher-level functions further down. NB: As and where there's no error
 * checking, take a look lower down where these functions are called, the
 * checking and error handling is probably down there.
 */

/* utility function to obtain a context */
static int get_context(SW_CONTEXT_HANDLE *hac)
{
    SW_STATUS status;

    status = p_CSwift_AcquireAccContext(hac);
    if (status != SW_OK)
        return 0;
    return 1;
}

/* similarly to release one. */
static void release_context(SW_CONTEXT_HANDLE hac)
{
    p_CSwift_ReleaseAccContext(hac);
}

/* Destructor (complements the "ENGINE_cswift()" constructor) */
static int cswift_destroy(ENGINE *e)
{
    free_CSWIFT_LIBNAME();
    ERR_unload_CSWIFT_strings();
    return 1;
}

/* (de)initialisation functions. */
static int cswift_init(ENGINE *e)
{
    SW_CONTEXT_HANDLE hac;
    t_swAcquireAccContext *p1;
    t_swAttachKeyParam *p2;
    t_swSimpleRequest *p3;
    t_swReleaseAccContext *p4;

    if (cswift_dso != NULL) {
        CSWIFTerr(CSWIFT_F_CSWIFT_INIT, CSWIFT_R_ALREADY_LOADED);
        goto err;
    }
    /* Attempt to load libswift.so/swift.dll/whatever. */
    cswift_dso = DSO_load(NULL, get_CSWIFT_LIBNAME(), NULL, 0);
    if (cswift_dso == NULL) {
        CSWIFTerr(CSWIFT_F_CSWIFT_INIT, CSWIFT_R_NOT_LOADED);
        goto err;
    }
    if (!(p1 = (t_swAcquireAccContext *)
          DSO_bind_func(cswift_dso, CSWIFT_F1)) ||
        !(p2 = (t_swAttachKeyParam *)
          DSO_bind_func(cswift_dso, CSWIFT_F2)) ||
        !(p3 = (t_swSimpleRequest *)
          DSO_bind_func(cswift_dso, CSWIFT_F3)) ||
        !(p4 = (t_swReleaseAccContext *)
          DSO_bind_func(cswift_dso, CSWIFT_F4))) {
        CSWIFTerr(CSWIFT_F_CSWIFT_INIT, CSWIFT_R_NOT_LOADED);
        goto err;
    }
    /* Copy the pointers */
    p_CSwift_AcquireAccContext = p1;
    p_CSwift_AttachKeyParam = p2;
    p_CSwift_SimpleRequest = p3;
    p_CSwift_ReleaseAccContext = p4;
    /*
     * Try and get a context - if not, we may have a DSO but no accelerator!
     */
    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_INIT, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    release_context(hac);
    /* Everything's fine. */
    return 1;
 err:
    if (cswift_dso) {
        DSO_free(cswift_dso);
        cswift_dso = NULL;
    }
    p_CSwift_AcquireAccContext = NULL;
    p_CSwift_AttachKeyParam = NULL;
    p_CSwift_SimpleRequest = NULL;
    p_CSwift_ReleaseAccContext = NULL;
    return 0;
}

static int cswift_finish(ENGINE *e)
{
    free_CSWIFT_LIBNAME();
    if (cswift_dso == NULL) {
        CSWIFTerr(CSWIFT_F_CSWIFT_FINISH, CSWIFT_R_NOT_LOADED);
        return 0;
    }
    if (!DSO_free(cswift_dso)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_FINISH, CSWIFT_R_UNIT_FAILURE);
        return 0;
    }
    cswift_dso = NULL;
    p_CSwift_AcquireAccContext = NULL;
    p_CSwift_AttachKeyParam = NULL;
    p_CSwift_SimpleRequest = NULL;
    p_CSwift_ReleaseAccContext = NULL;
    return 1;
}

static int cswift_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
{
    int initialised = ((cswift_dso == NULL) ? 0 : 1);
    switch (cmd) {
    case CSWIFT_CMD_SO_PATH:
        if (p == NULL) {
            CSWIFTerr(CSWIFT_F_CSWIFT_CTRL, ERR_R_PASSED_NULL_PARAMETER);
            return 0;
        }
        if (initialised) {
            CSWIFTerr(CSWIFT_F_CSWIFT_CTRL, CSWIFT_R_ALREADY_LOADED);
            return 0;
        }
        return set_CSWIFT_LIBNAME((const char *)p);
    default:
        break;
    }
    CSWIFTerr(CSWIFT_F_CSWIFT_CTRL, CSWIFT_R_CTRL_COMMAND_NOT_IMPLEMENTED);
    return 0;
}

/* Un petit mod_exp */
static int cswift_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                          const BIGNUM *m, BN_CTX *ctx)
{
    /*
     * I need somewhere to store temporary serialised values for use with the
     * CryptoSwift API calls. A neat cheat - I'll use BIGNUMs from the BN_CTX
     * but access their arrays directly as byte arrays <grin>. This way I
     * don't have to clean anything up.
     */
    BIGNUM *modulus;
    BIGNUM *exponent;
    BIGNUM *argument;
    BIGNUM *result;
    SW_STATUS sw_status;
    SW_LARGENUMBER arg, res;
    SW_PARAM sw_param;
    SW_CONTEXT_HANDLE hac;
    int to_return, acquired;

    modulus = exponent = argument = result = NULL;
    to_return = 0;              /* expect failure */
    acquired = 0;

    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    acquired = 1;
    /* Prepare the params */
    BN_CTX_start(ctx);
    modulus = BN_CTX_get(ctx);
    exponent = BN_CTX_get(ctx);
    argument = BN_CTX_get(ctx);
    result = BN_CTX_get(ctx);
    if (!result) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_BN_CTX_FULL);
        goto err;
    }
    if (!bn_wexpand(modulus, m->top) || !bn_wexpand(exponent, p->top) ||
        !bn_wexpand(argument, a->top) || !bn_wexpand(result, m->top)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    sw_param.type = SW_ALG_EXP;
    sw_param.up.exp.modulus.nbytes = BN_bn2bin(m,
                                               (unsigned char *)modulus->d);
    sw_param.up.exp.modulus.value = (unsigned char *)modulus->d;
    sw_param.up.exp.exponent.nbytes = BN_bn2bin(p,
                                                (unsigned char *)exponent->d);
    sw_param.up.exp.exponent.value = (unsigned char *)exponent->d;
    /* Attach the key params */
    sw_status = p_CSwift_AttachKeyParam(hac, &sw_param);
    switch (sw_status) {
    case SW_OK:
        break;
    case SW_ERR_INPUT_SIZE:
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_BAD_KEY_SIZE);
        goto err;
    default:
        {
            char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
            CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", sw_status);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        }
        goto err;
    }
    /* Prepare the argument and response */
    arg.nbytes = BN_bn2bin(a, (unsigned char *)argument->d);
    arg.value = (unsigned char *)argument->d;
    res.nbytes = BN_num_bytes(m);
    memset(result->d, 0, res.nbytes);
    res.value = (unsigned char *)result->d;
    /* Perform the operation */
    if ((sw_status = p_CSwift_SimpleRequest(hac, SW_CMD_MODEXP, &arg, 1,
                                            &res, 1)) != SW_OK) {
        char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP, CSWIFT_R_REQUEST_FAILED);
        sprintf(tmpbuf, "%ld", sw_status);
        ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        goto err;
    }
    /* Convert the response */
    BN_bin2bn((unsigned char *)result->d, res.nbytes, r);
    to_return = 1;
 err:
    if (acquired)
        release_context(hac);
    BN_CTX_end(ctx);
    return to_return;
}

#  ifndef OPENSSL_NO_RSA
int cswift_bn_32copy(SW_LARGENUMBER *out, const BIGNUM *in)
{
    int mod;
    int numbytes = BN_num_bytes(in);

    mod = 0;
    while (((out->nbytes = (numbytes + mod)) % 32)) {
        mod++;
    }
    out->value = (unsigned char *)OPENSSL_malloc(out->nbytes);
    if (!out->value) {
        return 0;
    }
    BN_bn2bin(in, &out->value[mod]);
    if (mod)
        memset(out->value, 0, mod);

    return 1;
}
#  endif

#  ifndef OPENSSL_NO_RSA
/* Un petit mod_exp chinois */
static int cswift_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                              const BIGNUM *q, const BIGNUM *dmp1,
                              const BIGNUM *dmq1, const BIGNUM *iqmp,
                              BN_CTX *ctx)
{
    SW_STATUS sw_status;
    SW_LARGENUMBER arg, res;
    SW_PARAM sw_param;
    SW_CONTEXT_HANDLE hac;
    BIGNUM *result = NULL;
    BIGNUM *argument = NULL;
    int to_return = 0;          /* expect failure */
    int acquired = 0;

    sw_param.up.crt.p.value = NULL;
    sw_param.up.crt.q.value = NULL;
    sw_param.up.crt.dmp1.value = NULL;
    sw_param.up.crt.dmq1.value = NULL;
    sw_param.up.crt.iqmp.value = NULL;

    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    acquired = 1;

    /* Prepare the params */
    argument = BN_new();
    result = BN_new();
    if (!result || !argument) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_CTX_FULL);
        goto err;
    }

    sw_param.type = SW_ALG_CRT;
        /************************************************************************/
    /*
     * 04/02/2003
     */
    /*
     * Modified by Frederic Giudicelli (deny-all.com) to overcome the
     */
    /*
     * limitation of cswift with values not a multiple of 32
     */
        /************************************************************************/
    if (!cswift_bn_32copy(&sw_param.up.crt.p, p)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    if (!cswift_bn_32copy(&sw_param.up.crt.q, q)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    if (!cswift_bn_32copy(&sw_param.up.crt.dmp1, dmp1)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    if (!cswift_bn_32copy(&sw_param.up.crt.dmq1, dmq1)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    if (!cswift_bn_32copy(&sw_param.up.crt.iqmp, iqmp)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    if (!bn_wexpand(argument, a->top) || !bn_wexpand(result, p->top + q->top)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }

    /* Attach the key params */
    sw_status = p_CSwift_AttachKeyParam(hac, &sw_param);
    switch (sw_status) {
    case SW_OK:
        break;
    case SW_ERR_INPUT_SIZE:
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_BAD_KEY_SIZE);
        goto err;
    default:
        {
            char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
            CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", sw_status);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        }
        goto err;
    }
    /* Prepare the argument and response */
    arg.nbytes = BN_bn2bin(a, (unsigned char *)argument->d);
    arg.value = (unsigned char *)argument->d;
    res.nbytes = 2 * BN_num_bytes(p);
    memset(result->d, 0, res.nbytes);
    res.value = (unsigned char *)result->d;
    /* Perform the operation */
    if ((sw_status = p_CSwift_SimpleRequest(hac, SW_CMD_MODEXP_CRT, &arg, 1,
                                            &res, 1)) != SW_OK) {
        char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
        CSWIFTerr(CSWIFT_F_CSWIFT_MOD_EXP_CRT, CSWIFT_R_REQUEST_FAILED);
        sprintf(tmpbuf, "%ld", sw_status);
        ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        goto err;
    }
    /* Convert the response */
    BN_bin2bn((unsigned char *)result->d, res.nbytes, r);
    to_return = 1;
 err:
    if (sw_param.up.crt.p.value)
        OPENSSL_free(sw_param.up.crt.p.value);
    if (sw_param.up.crt.q.value)
        OPENSSL_free(sw_param.up.crt.q.value);
    if (sw_param.up.crt.dmp1.value)
        OPENSSL_free(sw_param.up.crt.dmp1.value);
    if (sw_param.up.crt.dmq1.value)
        OPENSSL_free(sw_param.up.crt.dmq1.value);
    if (sw_param.up.crt.iqmp.value)
        OPENSSL_free(sw_param.up.crt.iqmp.value);
    if (result)
        BN_free(result);
    if (argument)
        BN_free(argument);
    if (acquired)
        release_context(hac);
    return to_return;
}
#  endif

#  ifndef OPENSSL_NO_RSA
static int cswift_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
                              BN_CTX *ctx)
{
    int to_return = 0;
    const RSA_METHOD *def_rsa_method;

    if (!rsa->p || !rsa->q || !rsa->dmp1 || !rsa->dmq1 || !rsa->iqmp) {
        CSWIFTerr(CSWIFT_F_CSWIFT_RSA_MOD_EXP,
                  CSWIFT_R_MISSING_KEY_COMPONENTS);
        goto err;
    }

    /* Try the limits of RSA (2048 bits) */
    if (BN_num_bytes(rsa->p) > 128 ||
        BN_num_bytes(rsa->q) > 128 ||
        BN_num_bytes(rsa->dmp1) > 128 ||
        BN_num_bytes(rsa->dmq1) > 128 || BN_num_bytes(rsa->iqmp) > 128) {
#   ifdef RSA_NULL
        def_rsa_method = RSA_null_method();
#   else
        def_rsa_method = RSA_PKCS1_SSLeay();
#   endif
        if (def_rsa_method)
            return def_rsa_method->rsa_mod_exp(r0, I, rsa, ctx);
    }

    to_return = cswift_mod_exp_crt(r0, I, rsa->p, rsa->q, rsa->dmp1,
                                   rsa->dmq1, rsa->iqmp, ctx);
 err:
    return to_return;
}

/* This function is aliased to mod_exp (with the mont stuff dropped). */
static int cswift_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                               const BIGNUM *m, BN_CTX *ctx,
                               BN_MONT_CTX *m_ctx)
{
    const RSA_METHOD *def_rsa_method;

    /* Try the limits of RSA (2048 bits) */
    if (BN_num_bytes(r) > 256 ||
        BN_num_bytes(a) > 256 || BN_num_bytes(m) > 256) {
#   ifdef RSA_NULL
        def_rsa_method = RSA_null_method();
#   else
        def_rsa_method = RSA_PKCS1_SSLeay();
#   endif
        if (def_rsa_method)
            return def_rsa_method->bn_mod_exp(r, a, p, m, ctx, m_ctx);
    }

    return cswift_mod_exp(r, a, p, m, ctx);
}
#  endif                        /* OPENSSL_NO_RSA */

#  ifndef OPENSSL_NO_DSA
static DSA_SIG *cswift_dsa_sign(const unsigned char *dgst, int dlen, DSA *dsa)
{
    SW_CONTEXT_HANDLE hac;
    SW_PARAM sw_param;
    SW_STATUS sw_status;
    SW_LARGENUMBER arg, res;
    BN_CTX *ctx;
    BIGNUM *dsa_p = NULL;
    BIGNUM *dsa_q = NULL;
    BIGNUM *dsa_g = NULL;
    BIGNUM *dsa_key = NULL;
    BIGNUM *result = NULL;
    DSA_SIG *to_return = NULL;
    int acquired = 0;

    if ((ctx = BN_CTX_new()) == NULL)
        goto err;
    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    acquired = 1;
    /* Prepare the params */
    BN_CTX_start(ctx);
    dsa_p = BN_CTX_get(ctx);
    dsa_q = BN_CTX_get(ctx);
    dsa_g = BN_CTX_get(ctx);
    dsa_key = BN_CTX_get(ctx);
    result = BN_CTX_get(ctx);
    if (!result) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_BN_CTX_FULL);
        goto err;
    }
    if (!bn_wexpand(dsa_p, dsa->p->top) ||
        !bn_wexpand(dsa_q, dsa->q->top) ||
        !bn_wexpand(dsa_g, dsa->g->top) ||
        !bn_wexpand(dsa_key, dsa->priv_key->top) ||
        !bn_wexpand(result, dsa->p->top)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    sw_param.type = SW_ALG_DSA;
    sw_param.up.dsa.p.nbytes = BN_bn2bin(dsa->p, (unsigned char *)dsa_p->d);
    sw_param.up.dsa.p.value = (unsigned char *)dsa_p->d;
    sw_param.up.dsa.q.nbytes = BN_bn2bin(dsa->q, (unsigned char *)dsa_q->d);
    sw_param.up.dsa.q.value = (unsigned char *)dsa_q->d;
    sw_param.up.dsa.g.nbytes = BN_bn2bin(dsa->g, (unsigned char *)dsa_g->d);
    sw_param.up.dsa.g.value = (unsigned char *)dsa_g->d;
    sw_param.up.dsa.key.nbytes = BN_bn2bin(dsa->priv_key,
                                           (unsigned char *)dsa_key->d);
    sw_param.up.dsa.key.value = (unsigned char *)dsa_key->d;
    /* Attach the key params */
    sw_status = p_CSwift_AttachKeyParam(hac, &sw_param);
    switch (sw_status) {
    case SW_OK:
        break;
    case SW_ERR_INPUT_SIZE:
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_BAD_KEY_SIZE);
        goto err;
    default:
        {
            char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
            CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", sw_status);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        }
        goto err;
    }
    /* Prepare the argument and response */
    arg.nbytes = dlen;
    arg.value = (unsigned char *)dgst;
    res.nbytes = BN_num_bytes(dsa->p);
    memset(result->d, 0, res.nbytes);
    res.value = (unsigned char *)result->d;
    /* Perform the operation */
    sw_status = p_CSwift_SimpleRequest(hac, SW_CMD_DSS_SIGN, &arg, 1,
                                       &res, 1);
    if (sw_status != SW_OK) {
        char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_SIGN, CSWIFT_R_REQUEST_FAILED);
        sprintf(tmpbuf, "%ld", sw_status);
        ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        goto err;
    }
    /* Convert the response */
    if ((to_return = DSA_SIG_new()) == NULL)
        goto err;
    to_return->r = BN_bin2bn((unsigned char *)result->d, 20, NULL);
    to_return->s = BN_bin2bn((unsigned char *)result->d + 20, 20, NULL);

 err:
    if (acquired)
        release_context(hac);
    if (ctx) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    return to_return;
}

static int cswift_dsa_verify(const unsigned char *dgst, int dgst_len,
                             DSA_SIG *sig, DSA *dsa)
{
    SW_CONTEXT_HANDLE hac;
    SW_PARAM sw_param;
    SW_STATUS sw_status;
    SW_LARGENUMBER arg[2], res;
    unsigned long sig_result;
    BN_CTX *ctx;
    BIGNUM *dsa_p = NULL;
    BIGNUM *dsa_q = NULL;
    BIGNUM *dsa_g = NULL;
    BIGNUM *dsa_key = NULL;
    BIGNUM *argument = NULL;
    int to_return = -1;
    int acquired = 0;

    if ((ctx = BN_CTX_new()) == NULL)
        goto err;
    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    acquired = 1;
    /* Prepare the params */
    BN_CTX_start(ctx);
    dsa_p = BN_CTX_get(ctx);
    dsa_q = BN_CTX_get(ctx);
    dsa_g = BN_CTX_get(ctx);
    dsa_key = BN_CTX_get(ctx);
    argument = BN_CTX_get(ctx);
    if (!argument) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_BN_CTX_FULL);
        goto err;
    }
    if (!bn_wexpand(dsa_p, dsa->p->top) ||
        !bn_wexpand(dsa_q, dsa->q->top) ||
        !bn_wexpand(dsa_g, dsa->g->top) ||
        !bn_wexpand(dsa_key, dsa->pub_key->top) ||
        !bn_wexpand(argument, 40)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_BN_EXPAND_FAIL);
        goto err;
    }
    sw_param.type = SW_ALG_DSA;
    sw_param.up.dsa.p.nbytes = BN_bn2bin(dsa->p, (unsigned char *)dsa_p->d);
    sw_param.up.dsa.p.value = (unsigned char *)dsa_p->d;
    sw_param.up.dsa.q.nbytes = BN_bn2bin(dsa->q, (unsigned char *)dsa_q->d);
    sw_param.up.dsa.q.value = (unsigned char *)dsa_q->d;
    sw_param.up.dsa.g.nbytes = BN_bn2bin(dsa->g, (unsigned char *)dsa_g->d);
    sw_param.up.dsa.g.value = (unsigned char *)dsa_g->d;
    sw_param.up.dsa.key.nbytes = BN_bn2bin(dsa->pub_key,
                                           (unsigned char *)dsa_key->d);
    sw_param.up.dsa.key.value = (unsigned char *)dsa_key->d;
    /* Attach the key params */
    sw_status = p_CSwift_AttachKeyParam(hac, &sw_param);
    switch (sw_status) {
    case SW_OK:
        break;
    case SW_ERR_INPUT_SIZE:
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_BAD_KEY_SIZE);
        goto err;
    default:
        {
            char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
            CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", sw_status);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        }
        goto err;
    }
    /* Prepare the argument and response */
    arg[0].nbytes = dgst_len;
    arg[0].value = (unsigned char *)dgst;
    arg[1].nbytes = 40;
    arg[1].value = (unsigned char *)argument->d;
    memset(arg[1].value, 0, 40);
    BN_bn2bin(sig->r, arg[1].value + 20 - BN_num_bytes(sig->r));
    BN_bn2bin(sig->s, arg[1].value + 40 - BN_num_bytes(sig->s));
    res.nbytes = 4;             /* unsigned long */
    res.value = (unsigned char *)(&sig_result);
    /* Perform the operation */
    sw_status = p_CSwift_SimpleRequest(hac, SW_CMD_DSS_VERIFY, arg, 2,
                                       &res, 1);
    if (sw_status != SW_OK) {
        char tmpbuf[DECIMAL_SIZE(sw_status) + 1];
        CSWIFTerr(CSWIFT_F_CSWIFT_DSA_VERIFY, CSWIFT_R_REQUEST_FAILED);
        sprintf(tmpbuf, "%ld", sw_status);
        ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
        goto err;
    }
    /* Convert the response */
    to_return = ((sig_result == 0) ? 0 : 1);

 err:
    if (acquired)
        release_context(hac);
    if (ctx) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    return to_return;
}
#  endif

#  ifndef OPENSSL_NO_DH
/* This function is aliased to mod_exp (with the dh and mont dropped). */
static int cswift_mod_exp_dh(const DH *dh, BIGNUM *r,
                             const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
{
    return cswift_mod_exp(r, a, p, m, ctx);
}
#  endif

/* Random bytes are good */
static int cswift_rand_bytes(unsigned char *buf, int num)
{
    SW_CONTEXT_HANDLE hac;
    SW_STATUS swrc;
    SW_LARGENUMBER largenum;
    int acquired = 0;
    int to_return = 0;          /* assume failure */
    unsigned char buf32[1024];

    if (!get_context(&hac)) {
        CSWIFTerr(CSWIFT_F_CSWIFT_RAND_BYTES, CSWIFT_R_UNIT_FAILURE);
        goto err;
    }
    acquired = 1;

        /************************************************************************/
    /*
     * 04/02/2003
     */
    /*
     * Modified by Frederic Giudicelli (deny-all.com) to overcome the
     */
    /*
     * limitation of cswift with values not a multiple of 32
     */
        /************************************************************************/

    while (num >= (int)sizeof(buf32)) {
        largenum.value = buf;
        largenum.nbytes = sizeof(buf32);
        /*-
         * tell CryptoSwift how many bytes we want and where we want it.
         * Note: - CryptoSwift cannot do more than 4096 bytes at a time.
         *       - CryptoSwift can only do multiple of 32-bits.
         */
        swrc =
            p_CSwift_SimpleRequest(hac, SW_CMD_RAND, NULL, 0, &largenum, 1);
        if (swrc != SW_OK) {
            char tmpbuf[20];
            CSWIFTerr(CSWIFT_F_CSWIFT_RAND_BYTES, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", swrc);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
            goto err;
        }
        buf += sizeof(buf32);
        num -= sizeof(buf32);
    }
    if (num) {
        largenum.nbytes = sizeof(buf32);
        largenum.value = buf32;
        swrc =
            p_CSwift_SimpleRequest(hac, SW_CMD_RAND, NULL, 0, &largenum, 1);
        if (swrc != SW_OK) {
            char tmpbuf[20];
            CSWIFTerr(CSWIFT_F_CSWIFT_RAND_BYTES, CSWIFT_R_REQUEST_FAILED);
            sprintf(tmpbuf, "%ld", swrc);
            ERR_add_error_data(2, "CryptoSwift error number is ", tmpbuf);
            goto err;
        }
        memcpy(buf, largenum.value, num);
    }

    to_return = 1;              /* success */
 err:
    if (acquired)
        release_context(hac);

    return to_return;
}

static int cswift_rand_status(void)
{
    return 1;
}

/*
 * This stuff is needed if this ENGINE is being compiled into a
 * self-contained shared-library.
 */
#  ifndef OPENSSL_NO_DYNAMIC_ENGINE
static int bind_fn(ENGINE *e, const char *id)
{
    if (id && (strcmp(id, engine_cswift_id) != 0))
        return 0;
    if (!bind_helper(e))
        return 0;
    return 1;
}

IMPLEMENT_DYNAMIC_CHECK_FN()
    IMPLEMENT_DYNAMIC_BIND_FN(bind_fn)
#  endif                        /* OPENSSL_NO_DYNAMIC_ENGINE */
# endif                         /* !OPENSSL_NO_HW_CSWIFT */
#endif                          /* !OPENSSL_NO_HW */