/* crypto/engine/hw_ubsec.c */
/*
 * Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL project
 * 2000. Cloned shamelessly by Joe Tardo.
 */
/* ====================================================================
 * 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/bn.h>

#ifndef OPENSSL_NO_HW
# ifndef OPENSSL_NO_HW_UBSEC

#  ifdef FLAT_INC
#   include "hw_ubsec.h"
#  else
#   include "vendor_defns/hw_ubsec.h"
#  endif

#  define UBSEC_LIB_NAME "ubsec engine"
#  include "e_ubsec_err.c"

#  define FAIL_TO_SOFTWARE -15

static int ubsec_destroy(ENGINE *e);
static int ubsec_init(ENGINE *e);
static int ubsec_finish(ENGINE *e);
static int ubsec_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void));
static int ubsec_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                         const BIGNUM *m, BN_CTX *ctx);
#  ifndef OPENSSL_NO_RSA
static int ubsec_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *q, const BIGNUM *dp,
                             const BIGNUM *dq, const BIGNUM *qinv,
                             BN_CTX *ctx);
static int ubsec_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
                             BN_CTX *ctx);
static int ubsec_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
#   ifdef NOT_USED
static int ubsec_dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1,
                             BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m,
                             BN_CTX *ctx, BN_MONT_CTX *in_mont);
static int ubsec_mod_exp_dsa(DSA *dsa, BIGNUM *r, BIGNUM *a,
                             const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
                             BN_MONT_CTX *m_ctx);
#   endif
static DSA_SIG *ubsec_dsa_do_sign(const unsigned char *dgst, int dlen,
                                  DSA *dsa);
static int ubsec_dsa_verify(const unsigned char *dgst, int dgst_len,
                            DSA_SIG *sig, DSA *dsa);
#  endif
#  ifndef OPENSSL_NO_DH
static int ubsec_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);
static int ubsec_dh_compute_key(unsigned char *key, const BIGNUM *pub_key,
                                DH *dh);
static int ubsec_dh_generate_key(DH *dh);
#  endif

#  ifdef NOT_USED
static int ubsec_rand_bytes(unsigned char *buf, int num);
static int ubsec_rand_status(void);
#  endif

#  define UBSEC_CMD_SO_PATH               ENGINE_CMD_BASE
static const ENGINE_CMD_DEFN ubsec_cmd_defns[] = {
    {UBSEC_CMD_SO_PATH,
     "SO_PATH",
     "Specifies the path to the 'ubsec' 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 ubsec_rsa = {
    "UBSEC RSA method",
    NULL,
    NULL,
    NULL,
    NULL,
    ubsec_rsa_mod_exp,
    ubsec_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 ubsec_dsa = {
    "UBSEC DSA method",
    ubsec_dsa_do_sign,          /* dsa_do_sign */
    NULL,                       /* dsa_sign_setup */
    ubsec_dsa_verify,           /* dsa_do_verify */
    NULL,                       /* ubsec_dsa_mod_exp *//* dsa_mod_exp */
    NULL,                       /* ubsec_mod_exp_dsa *//* 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 ubsec_dh = {
    "UBSEC DH method",
    ubsec_dh_generate_key,
    ubsec_dh_compute_key,
    ubsec_mod_exp_dh,
    NULL,
    NULL,
    0,
    NULL,
    NULL
};
#  endif

/* Constants used when creating the ENGINE */
static const char *engine_ubsec_id = "ubsec";
static const char *engine_ubsec_name = "UBSEC hardware engine support";

/*
 * This internal function is used by ENGINE_ubsec() 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
#   ifndef HAVE_UBSEC_DH
    const DH_METHOD *meth3;
#   endif                       /* HAVE_UBSEC_DH */
#  endif
    if (!ENGINE_set_id(e, engine_ubsec_id) ||
        !ENGINE_set_name(e, engine_ubsec_name) ||
#  ifndef OPENSSL_NO_RSA
        !ENGINE_set_RSA(e, &ubsec_rsa) ||
#  endif
#  ifndef OPENSSL_NO_DSA
        !ENGINE_set_DSA(e, &ubsec_dsa) ||
#  endif
#  ifndef OPENSSL_NO_DH
        !ENGINE_set_DH(e, &ubsec_dh) ||
#  endif
        !ENGINE_set_destroy_function(e, ubsec_destroy) ||
        !ENGINE_set_init_function(e, ubsec_init) ||
        !ENGINE_set_finish_function(e, ubsec_finish) ||
        !ENGINE_set_ctrl_function(e, ubsec_ctrl) ||
        !ENGINE_set_cmd_defns(e, ubsec_cmd_defns))
        return 0;

#  ifndef OPENSSL_NO_RSA
    /*
     * We know that the "PKCS1_OpenSSL()" functions hook properly to the
     * Broadcom-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_OpenSSL();
    ubsec_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
    ubsec_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
    ubsec_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
    ubsec_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
#  endif

#  ifndef OPENSSL_NO_DH
#   ifndef HAVE_UBSEC_DH
    /* Much the same for Diffie-Hellman */
    meth3 = DH_OpenSSL();
    ubsec_dh.generate_key = meth3->generate_key;
    ubsec_dh.compute_key = meth3->compute_key;
#   endif                       /* HAVE_UBSEC_DH */
#  endif

    /* Ensure the ubsec error handling is set up */
    ERR_load_UBSEC_strings();
    return 1;
}

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

void ENGINE_load_ubsec(void)
{
    /* Copied from eng_[openssl|dyn].c */
    ENGINE *toadd = engine_ubsec();
    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
 * UBSEC 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 *ubsec_dso = NULL;

/*
 * These are the function pointers that are (un)set when the library has
 * successfully (un)loaded.
 */

static t_UBSEC_ubsec_bytes_to_bits *p_UBSEC_ubsec_bytes_to_bits = NULL;
static t_UBSEC_ubsec_bits_to_bytes *p_UBSEC_ubsec_bits_to_bytes = NULL;
static t_UBSEC_ubsec_open *p_UBSEC_ubsec_open = NULL;
static t_UBSEC_ubsec_close *p_UBSEC_ubsec_close = NULL;
#  ifndef OPENSSL_NO_DH
static t_UBSEC_diffie_hellman_generate_ioctl
    * p_UBSEC_diffie_hellman_generate_ioctl = NULL;
static t_UBSEC_diffie_hellman_agree_ioctl *p_UBSEC_diffie_hellman_agree_ioctl
    = NULL;
#  endif
#  ifndef OPENSSL_NO_RSA
static t_UBSEC_rsa_mod_exp_ioctl *p_UBSEC_rsa_mod_exp_ioctl = NULL;
static t_UBSEC_rsa_mod_exp_crt_ioctl *p_UBSEC_rsa_mod_exp_crt_ioctl = NULL;
#  endif
#  ifndef OPENSSL_NO_DSA
static t_UBSEC_dsa_sign_ioctl *p_UBSEC_dsa_sign_ioctl = NULL;
static t_UBSEC_dsa_verify_ioctl *p_UBSEC_dsa_verify_ioctl = NULL;
#  endif
static t_UBSEC_math_accelerate_ioctl *p_UBSEC_math_accelerate_ioctl = NULL;
static t_UBSEC_rng_ioctl *p_UBSEC_rng_ioctl = NULL;
static t_UBSEC_max_key_len_ioctl *p_UBSEC_max_key_len_ioctl = NULL;

static int max_key_len = 1024;  /* ??? */

/*
 * These are the static string constants for the DSO file name and the function
 * symbol names to bind to.
 */

static const char *UBSEC_LIBNAME = NULL;
static const char *get_UBSEC_LIBNAME(void)
{
    if (UBSEC_LIBNAME)
        return UBSEC_LIBNAME;
    return "ubsec";
}

static void free_UBSEC_LIBNAME(void)
{
    OPENSSL_free(UBSEC_LIBNAME);
    UBSEC_LIBNAME = NULL;
}

static long set_UBSEC_LIBNAME(const char *name)
{
    free_UBSEC_LIBNAME();
    return (((UBSEC_LIBNAME = OPENSSL_strdup(name)) != NULL) ? 1 : 0);
}

static const char *UBSEC_F1 = "ubsec_bytes_to_bits";
static const char *UBSEC_F2 = "ubsec_bits_to_bytes";
static const char *UBSEC_F3 = "ubsec_open";
static const char *UBSEC_F4 = "ubsec_close";
#  ifndef OPENSSL_NO_DH
static const char *UBSEC_F5 = "diffie_hellman_generate_ioctl";
static const char *UBSEC_F6 = "diffie_hellman_agree_ioctl";
#  endif
/* #ifndef OPENSSL_NO_RSA */
static const char *UBSEC_F7 = "rsa_mod_exp_ioctl";
static const char *UBSEC_F8 = "rsa_mod_exp_crt_ioctl";
/* #endif */
#  ifndef OPENSSL_NO_DSA
static const char *UBSEC_F9 = "dsa_sign_ioctl";
static const char *UBSEC_F10 = "dsa_verify_ioctl";
#  endif
static const char *UBSEC_F11 = "math_accelerate_ioctl";
static const char *UBSEC_F12 = "rng_ioctl";
static const char *UBSEC_F13 = "ubsec_max_key_len_ioctl";

/* Destructor (complements the "ENGINE_ubsec()" constructor) */
static int ubsec_destroy(ENGINE *e)
{
    free_UBSEC_LIBNAME();
    ERR_unload_UBSEC_strings();
    return 1;
}

/* (de)initialisation functions. */
static int ubsec_init(ENGINE *e)
{
    t_UBSEC_ubsec_bytes_to_bits *p1;
    t_UBSEC_ubsec_bits_to_bytes *p2;
    t_UBSEC_ubsec_open *p3;
    t_UBSEC_ubsec_close *p4;
#  ifndef OPENSSL_NO_DH
    t_UBSEC_diffie_hellman_generate_ioctl *p5;
    t_UBSEC_diffie_hellman_agree_ioctl *p6;
#  endif
/* #ifndef OPENSSL_NO_RSA */
    t_UBSEC_rsa_mod_exp_ioctl *p7;
    t_UBSEC_rsa_mod_exp_crt_ioctl *p8;
/* #endif */
#  ifndef OPENSSL_NO_DSA
    t_UBSEC_dsa_sign_ioctl *p9;
    t_UBSEC_dsa_verify_ioctl *p10;
#  endif
    t_UBSEC_math_accelerate_ioctl *p11;
    t_UBSEC_rng_ioctl *p12;
    t_UBSEC_max_key_len_ioctl *p13;
    int fd = 0;

    if (ubsec_dso != NULL) {
        UBSECerr(UBSEC_F_UBSEC_INIT, UBSEC_R_ALREADY_LOADED);
        goto err;
    }
    /*
     * Attempt to load libubsec.so/ubsec.dll/whatever.
     */
    ubsec_dso = DSO_load(NULL, get_UBSEC_LIBNAME(), NULL, 0);
    if (ubsec_dso == NULL) {
        UBSECerr(UBSEC_F_UBSEC_INIT, UBSEC_R_DSO_FAILURE);
        goto err;
    }

#define BINDIT(t, name) (t *)DSO_bind_func(ubsec_dso, name)
    if ((p1 = BINDIT(t_UBSEC_ubsec_bytes_to_bits, UBSEC_F1)) == NULL
        || (p2 = BINDIT(t_UBSEC_ubsec_bits_to_bytes, UBSEC_F2)) == NULL
        || (p3 = BINDIT(t_UBSEC_ubsec_open, UBSEC_F3)) == NULL
        || (p4 = BINDIT(t_UBSEC_ubsec_close, UBSEC_F4)) == NULL
#  ifndef OPENSSL_NO_DH
        || (p5 = BINDIT(t_UBSEC_diffie_hellman_generate_ioctl, UBSEC_F5)) == NULL
        || (p6 = BINDIT(t_UBSEC_diffie_hellman_agree_ioctl, UBSEC_F6)) == NULL
#  endif
/* #ifndef OPENSSL_NO_RSA */
        || (p7 = BINDIT(t_UBSEC_rsa_mod_exp_ioctl, UBSEC_F7)) == NULL
        || (p8 = BINDIT(t_UBSEC_rsa_mod_exp_crt_ioctl, UBSEC_F8)) == NULL
/* #endif */
#  ifndef OPENSSL_NO_DSA
        || (p9 = BINDIT(t_UBSEC_dsa_sign_ioctl, UBSEC_F9)) == NULL
        || (p10 = BINDIT(t_UBSEC_dsa_verify_ioctl, UBSEC_F10)) == NULL
#  endif
        || (p11 = BINDIT(t_UBSEC_math_accelerate_ioctl, UBSEC_F11)) == NULL
        || (p12 = BINDIT(t_UBSEC_rng_ioctl, UBSEC_F12)) == NULL
        || (p13 = BINDIT(t_UBSEC_max_key_len_ioctl, UBSEC_F13)) == NULL) {
        UBSECerr(UBSEC_F_UBSEC_INIT, UBSEC_R_DSO_FAILURE);
        goto err;
    }

    /* Copy the pointers */
    p_UBSEC_ubsec_bytes_to_bits = p1;
    p_UBSEC_ubsec_bits_to_bytes = p2;
    p_UBSEC_ubsec_open = p3;
    p_UBSEC_ubsec_close = p4;
#  ifndef OPENSSL_NO_DH
    p_UBSEC_diffie_hellman_generate_ioctl = p5;
    p_UBSEC_diffie_hellman_agree_ioctl = p6;
#  endif
#  ifndef OPENSSL_NO_RSA
    p_UBSEC_rsa_mod_exp_ioctl = p7;
    p_UBSEC_rsa_mod_exp_crt_ioctl = p8;
#  endif
#  ifndef OPENSSL_NO_DSA
    p_UBSEC_dsa_sign_ioctl = p9;
    p_UBSEC_dsa_verify_ioctl = p10;
#  endif
    p_UBSEC_math_accelerate_ioctl = p11;
    p_UBSEC_rng_ioctl = p12;
    p_UBSEC_max_key_len_ioctl = p13;

    /* Perform an open to see if there's actually any unit running. */
    if (((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) > 0)
        && (p_UBSEC_max_key_len_ioctl(fd, &max_key_len) == 0)) {
        p_UBSEC_ubsec_close(fd);
        return 1;
    } else {
        UBSECerr(UBSEC_F_UBSEC_INIT, UBSEC_R_UNIT_FAILURE);
    }

 err:
    DSO_free(ubsec_dso);
    ubsec_dso = NULL;
    p_UBSEC_ubsec_bytes_to_bits = NULL;
    p_UBSEC_ubsec_bits_to_bytes = NULL;
    p_UBSEC_ubsec_open = NULL;
    p_UBSEC_ubsec_close = NULL;
#  ifndef OPENSSL_NO_DH
    p_UBSEC_diffie_hellman_generate_ioctl = NULL;
    p_UBSEC_diffie_hellman_agree_ioctl = NULL;
#  endif
#  ifndef OPENSSL_NO_RSA
    p_UBSEC_rsa_mod_exp_ioctl = NULL;
    p_UBSEC_rsa_mod_exp_crt_ioctl = NULL;
#  endif
#  ifndef OPENSSL_NO_DSA
    p_UBSEC_dsa_sign_ioctl = NULL;
    p_UBSEC_dsa_verify_ioctl = NULL;
#  endif
    p_UBSEC_math_accelerate_ioctl = NULL;
    p_UBSEC_rng_ioctl = NULL;
    p_UBSEC_max_key_len_ioctl = NULL;

    return 0;
}

static int ubsec_finish(ENGINE *e)
{
    free_UBSEC_LIBNAME();
    if (ubsec_dso == NULL) {
        UBSECerr(UBSEC_F_UBSEC_FINISH, UBSEC_R_NOT_LOADED);
        return 0;
    }
    if (!DSO_free(ubsec_dso)) {
        UBSECerr(UBSEC_F_UBSEC_FINISH, UBSEC_R_DSO_FAILURE);
        return 0;
    }
    ubsec_dso = NULL;
    p_UBSEC_ubsec_bytes_to_bits = NULL;
    p_UBSEC_ubsec_bits_to_bytes = NULL;
    p_UBSEC_ubsec_open = NULL;
    p_UBSEC_ubsec_close = NULL;
#  ifndef OPENSSL_NO_DH
    p_UBSEC_diffie_hellman_generate_ioctl = NULL;
    p_UBSEC_diffie_hellman_agree_ioctl = NULL;
#  endif
#  ifndef OPENSSL_NO_RSA
    p_UBSEC_rsa_mod_exp_ioctl = NULL;
    p_UBSEC_rsa_mod_exp_crt_ioctl = NULL;
#  endif
#  ifndef OPENSSL_NO_DSA
    p_UBSEC_dsa_sign_ioctl = NULL;
    p_UBSEC_dsa_verify_ioctl = NULL;
#  endif
    p_UBSEC_math_accelerate_ioctl = NULL;
    p_UBSEC_rng_ioctl = NULL;
    p_UBSEC_max_key_len_ioctl = NULL;
    return 1;
}

static int ubsec_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
{
    int initialised = ((ubsec_dso == NULL) ? 0 : 1);
    switch (cmd) {
    case UBSEC_CMD_SO_PATH:
        if (p == NULL) {
            UBSECerr(UBSEC_F_UBSEC_CTRL, ERR_R_PASSED_NULL_PARAMETER);
            return 0;
        }
        if (initialised) {
            UBSECerr(UBSEC_F_UBSEC_CTRL, UBSEC_R_ALREADY_LOADED);
            return 0;
        }
        return set_UBSEC_LIBNAME((const char *)p);
    default:
        break;
    }
    UBSECerr(UBSEC_F_UBSEC_CTRL, UBSEC_R_CTRL_COMMAND_NOT_IMPLEMENTED);
    return 0;
}

static int ubsec_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                         const BIGNUM *m, BN_CTX *ctx)
{
    int y_len = 0;
    int fd;

    if (ubsec_dso == NULL) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP, UBSEC_R_NOT_LOADED);
        return 0;
    }

    /* Check if hardware can't handle this argument. */
    y_len = BN_num_bits(m);
    if (y_len > max_key_len) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP, UBSEC_R_SIZE_TOO_LARGE_OR_TOO_SMALL);
        return BN_mod_exp(r, a, p, m, ctx);
    }

    if (!bn_wexpand(r, m->top)) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP, UBSEC_R_BN_EXPAND_FAIL);
        return 0;
    }

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        fd = 0;
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP, UBSEC_R_UNIT_FAILURE);
        return BN_mod_exp(r, a, p, m, ctx);
    }

    if (p_UBSEC_rsa_mod_exp_ioctl(fd, (unsigned char *)a->d, BN_num_bits(a),
                                  (unsigned char *)m->d, BN_num_bits(m),
                                  (unsigned char *)p->d, BN_num_bits(p),
                                  (unsigned char *)r->d, &y_len) != 0) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);

        return BN_mod_exp(r, a, p, m, ctx);
    }

    p_UBSEC_ubsec_close(fd);

    r->top = (BN_num_bits(m) + BN_BITS2 - 1) / BN_BITS2;
    return 1;
}

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

    if (!rsa->p || !rsa->q || !rsa->dmp1 || !rsa->dmq1 || !rsa->iqmp) {
        UBSECerr(UBSEC_F_UBSEC_RSA_MOD_EXP, UBSEC_R_MISSING_KEY_COMPONENTS);
        goto err;
    }

    to_return = ubsec_mod_exp_crt(r0, I, rsa->p, rsa->q, rsa->dmp1,
                                  rsa->dmq1, rsa->iqmp, ctx);
    if (to_return == FAIL_TO_SOFTWARE) {
        /*
         * Do in software as hardware failed.
         */
        const RSA_METHOD *meth = RSA_PKCS1_OpenSSL();
        to_return = (*meth->rsa_mod_exp) (r0, I, rsa, ctx);
    }
 err:
    return to_return;
}

static int ubsec_mod_exp_crt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *q, const BIGNUM *dp,
                             const BIGNUM *dq, const BIGNUM *qinv,
                             BN_CTX *ctx)
{
    int y_len, fd;

    y_len = BN_num_bits(p) + BN_num_bits(q);

    /* Check if hardware can't handle this argument. */
    if (y_len > max_key_len) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP_CRT,
                 UBSEC_R_SIZE_TOO_LARGE_OR_TOO_SMALL);
        return FAIL_TO_SOFTWARE;
    }

    if (!bn_wexpand(r, p->top + q->top + 1)) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP_CRT, UBSEC_R_BN_EXPAND_FAIL);
        return 0;
    }

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        fd = 0;
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP_CRT, UBSEC_R_UNIT_FAILURE);
        return FAIL_TO_SOFTWARE;
    }

    if (p_UBSEC_rsa_mod_exp_crt_ioctl(fd,
                                      (unsigned char *)a->d, BN_num_bits(a),
                                      (unsigned char *)qinv->d,
                                      BN_num_bits(qinv),
                                      (unsigned char *)dp->d, BN_num_bits(dp),
                                      (unsigned char *)p->d, BN_num_bits(p),
                                      (unsigned char *)dq->d, BN_num_bits(dq),
                                      (unsigned char *)q->d, BN_num_bits(q),
                                      (unsigned char *)r->d, &y_len) != 0) {
        UBSECerr(UBSEC_F_UBSEC_MOD_EXP_CRT, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);
        return FAIL_TO_SOFTWARE;
    }

    p_UBSEC_ubsec_close(fd);

    r->top = (BN_num_bits(p) + BN_num_bits(q) + BN_BITS2 - 1) / BN_BITS2;
    return 1;
}
#  endif

#  ifndef OPENSSL_NO_RSA

/*
 * This function is aliased to mod_exp (with the mont stuff dropped).
 */
static int ubsec_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                              const BIGNUM *m, BN_CTX *ctx,
                              BN_MONT_CTX *m_ctx)
{
    int ret = 0;

    /* Do in software if the key is too large for the hardware. */
    if (BN_num_bits(m) > max_key_len) {
        const RSA_METHOD *meth = RSA_PKCS1_OpenSSL();
        ret = (*meth->bn_mod_exp) (r, a, p, m, ctx, m_ctx);
    } else {
        ret = ubsec_mod_exp(r, a, p, m, ctx);
    }

    return ret;
}
#  endif

#  ifndef OPENSSL_NO_DH
/* This function is aliased to mod_exp (with the dh and mont dropped). */
static int ubsec_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 ubsec_mod_exp(r, a, p, m, ctx);
}
#  endif

#  ifndef OPENSSL_NO_DSA
static DSA_SIG *ubsec_dsa_do_sign(const unsigned char *dgst, int dlen,
                                  DSA *dsa)
{
    DSA_SIG *to_return = NULL;
    int s_len = 160, r_len = 160, d_len, fd;
    BIGNUM m, *r = NULL, *s = NULL;

    BN_init(&m);

    s = BN_new();
    r = BN_new();
    if ((s == NULL) || (r == NULL))
        goto err;

    d_len = p_UBSEC_ubsec_bytes_to_bits((unsigned char *)dgst, dlen);

    if (!bn_wexpand(r, (160 + BN_BITS2 - 1) / BN_BITS2) ||
        (!bn_wexpand(s, (160 + BN_BITS2 - 1) / BN_BITS2))) {
        UBSECerr(UBSEC_F_UBSEC_DSA_DO_SIGN, UBSEC_R_BN_EXPAND_FAIL);
        goto err;
    }

    if (BN_bin2bn(dgst, dlen, &m) == NULL) {
        UBSECerr(UBSEC_F_UBSEC_DSA_DO_SIGN, UBSEC_R_BN_EXPAND_FAIL);
        goto err;
    }

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        const DSA_METHOD *meth;
        fd = 0;
        UBSECerr(UBSEC_F_UBSEC_DSA_DO_SIGN, UBSEC_R_UNIT_FAILURE);
        meth = DSA_OpenSSL();
        to_return = meth->dsa_do_sign(dgst, dlen, dsa);
        goto err;
    }

    if (p_UBSEC_dsa_sign_ioctl(fd,
                               /* compute hash before signing */
                               0, (unsigned char *)dgst, d_len, NULL,
                               /* compute random value */
                               0,
                               (unsigned char *)dsa->p->d,
                               BN_num_bits(dsa->p),
                               (unsigned char *)dsa->q->d,
                               BN_num_bits(dsa->q),
                               (unsigned char *)dsa->g->d,
                               BN_num_bits(dsa->g),
                               (unsigned char *)dsa->priv_key->d,
                               BN_num_bits(dsa->priv_key),
                               (unsigned char *)r->d, &r_len,
                               (unsigned char *)s->d, &s_len) != 0) {
        const DSA_METHOD *meth;

        UBSECerr(UBSEC_F_UBSEC_DSA_DO_SIGN, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);
        meth = DSA_OpenSSL();
        to_return = meth->dsa_do_sign(dgst, dlen, dsa);

        goto err;
    }

    p_UBSEC_ubsec_close(fd);

    r->top = (160 + BN_BITS2 - 1) / BN_BITS2;
    s->top = (160 + BN_BITS2 - 1) / BN_BITS2;

    to_return = DSA_SIG_new();
    if (to_return == NULL) {
        UBSECerr(UBSEC_F_UBSEC_DSA_DO_SIGN, UBSEC_R_BN_EXPAND_FAIL);
        goto err;
    }

    to_return->r = r;
    to_return->s = s;

 err:
    if (!to_return) {
        BN_free(r);
        BN_free(s);
    }
    BN_clear_free(&m);
    return to_return;
}

static int ubsec_dsa_verify(const unsigned char *dgst, int dgst_len,
                            DSA_SIG *sig, DSA *dsa)
{
    int v_len, d_len;
    int to_return = 0;
    int fd;
    BIGNUM v, *pv = &v;

    BN_init(&v);

    if (!bn_wexpand(pv, dsa->p->top)) {
        UBSECerr(UBSEC_F_UBSEC_DSA_VERIFY, UBSEC_R_BN_EXPAND_FAIL);
        goto err;
    }

    v_len = BN_num_bits(dsa->p);

    d_len = p_UBSEC_ubsec_bytes_to_bits((unsigned char *)dgst, dgst_len);

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        const DSA_METHOD *meth;
        fd = 0;
        UBSECerr(UBSEC_F_UBSEC_DSA_VERIFY, UBSEC_R_UNIT_FAILURE);
        meth = DSA_OpenSSL();
        to_return = meth->dsa_do_verify(dgst, dgst_len, sig, dsa);
        goto err;
    }

    if (p_UBSEC_dsa_verify_ioctl(fd, 0, /* compute hash before signing */
                                 (unsigned char *)dgst, d_len,
                                 (unsigned char *)dsa->p->d,
                                 BN_num_bits(dsa->p),
                                 (unsigned char *)dsa->q->d,
                                 BN_num_bits(dsa->q),
                                 (unsigned char *)dsa->g->d,
                                 BN_num_bits(dsa->g),
                                 (unsigned char *)dsa->pub_key->d,
                                 BN_num_bits(dsa->pub_key),
                                 (unsigned char *)sig->r->d,
                                 BN_num_bits(sig->r),
                                 (unsigned char *)sig->s->d,
                                 BN_num_bits(sig->s), (unsigned char *)v.d,
                                 &v_len) != 0) {
        const DSA_METHOD *meth;
        UBSECerr(UBSEC_F_UBSEC_DSA_VERIFY, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);

        meth = DSA_OpenSSL();
        to_return = meth->dsa_do_verify(dgst, dgst_len, sig, dsa);

        goto err;
    }

    p_UBSEC_ubsec_close(fd);

    to_return = 1;
 err:
    BN_clear_free(&v);
    return to_return;
}
#  endif

#  ifndef OPENSSL_NO_DH
static int ubsec_dh_compute_key(unsigned char *key, const BIGNUM *pub_key,
                                DH *dh)
{
    int ret = -1, k_len, fd;

    k_len = BN_num_bits(dh->p);

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        const DH_METHOD *meth;
        UBSECerr(UBSEC_F_UBSEC_DH_COMPUTE_KEY, UBSEC_R_UNIT_FAILURE);
        meth = DH_OpenSSL();
        ret = meth->compute_key(key, pub_key, dh);
        goto err;
    }

    if (p_UBSEC_diffie_hellman_agree_ioctl(fd,
                                           (unsigned char *)dh->priv_key->d,
                                           BN_num_bits(dh->priv_key),
                                           (unsigned char *)pub_key->d,
                                           BN_num_bits(pub_key),
                                           (unsigned char *)dh->p->d,
                                           BN_num_bits(dh->p), key,
                                           &k_len) != 0) {
        /* Hardware's a no go, failover to software */
        const DH_METHOD *meth;
        UBSECerr(UBSEC_F_UBSEC_DH_COMPUTE_KEY, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);

        meth = DH_OpenSSL();
        ret = meth->compute_key(key, pub_key, dh);

        goto err;
    }

    p_UBSEC_ubsec_close(fd);

    ret = p_UBSEC_ubsec_bits_to_bytes(k_len);
 err:
    return ret;
}

static int ubsec_dh_generate_key(DH *dh)
{
    int ret = 0, random_bits = 0, pub_key_len = 0, priv_key_len = 0, fd;
    BIGNUM *pub_key = NULL;
    BIGNUM *priv_key = NULL;

    /*
     *  How many bits should Random x be? dh_key.c
     *  sets the range from 0 to num_bits(modulus) ???
     */

    if (dh->priv_key == NULL) {
        priv_key = BN_new();
        if (priv_key == NULL)
            goto err;
        priv_key_len = BN_num_bits(dh->p);
        if (bn_wexpand(priv_key, dh->p->top) == NULL)
            goto err;
        do
            if (!BN_rand_range(priv_key, dh->p))
                goto err;
        while (BN_is_zero(priv_key)) ;
        random_bits = BN_num_bits(priv_key);
    } else {
        priv_key = dh->priv_key;
    }

    if (dh->pub_key == NULL) {
        pub_key = BN_new();
        if (pub_key == NULL)
            goto err;
        pub_key_len = BN_num_bits(dh->p);
        if (bn_wexpand(pub_key, dh->p->top) == NULL)
            goto err;
    } else {
        pub_key = dh->pub_key;
    }

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        const DH_METHOD *meth;
        UBSECerr(UBSEC_F_UBSEC_DH_GENERATE_KEY, UBSEC_R_UNIT_FAILURE);
        meth = DH_OpenSSL();
        ret = meth->generate_key(dh);
        goto err;
    }

    if (p_UBSEC_diffie_hellman_generate_ioctl(fd,
                                              (unsigned char *)priv_key->d,
                                              &priv_key_len,
                                              (unsigned char *)pub_key->d,
                                              &pub_key_len,
                                              (unsigned char *)dh->g->d,
                                              BN_num_bits(dh->g),
                                              (unsigned char *)dh->p->d,
                                              BN_num_bits(dh->p), 0, 0,
                                              random_bits) != 0) {
        /* Hardware's a no go, failover to software */
        const DH_METHOD *meth;

        UBSECerr(UBSEC_F_UBSEC_DH_GENERATE_KEY, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);

        meth = DH_OpenSSL();
        ret = meth->generate_key(dh);

        goto err;
    }

    p_UBSEC_ubsec_close(fd);

    dh->pub_key = pub_key;
    dh->pub_key->top = (pub_key_len + BN_BITS2 - 1) / BN_BITS2;
    dh->priv_key = priv_key;
    dh->priv_key->top = (priv_key_len + BN_BITS2 - 1) / BN_BITS2;

    ret = 1;
 err:
    return ret;
}
#  endif

#  ifdef NOT_USED
static int ubsec_rand_bytes(unsigned char *buf, int num)
{
    int ret = 0, fd;

    if ((fd = p_UBSEC_ubsec_open(UBSEC_KEY_DEVICE_NAME)) <= 0) {
        const RAND_METHOD *meth;
        UBSECerr(UBSEC_F_UBSEC_RAND_BYTES, UBSEC_R_UNIT_FAILURE);
        num = p_UBSEC_ubsec_bits_to_bytes(num);
        meth = RAND_OpenSSL();
        meth->seed(buf, num);
        ret = meth->bytes(buf, num);
        goto err;
    }

    num *= 8;                   /* bytes to bits */

    if (p_UBSEC_rng_ioctl(fd, UBSEC_RNG_DIRECT, buf, &num) != 0) {
        /* Hardware's a no go, failover to software */
        const RAND_METHOD *meth;

        UBSECerr(UBSEC_F_UBSEC_RAND_BYTES, UBSEC_R_REQUEST_FAILED);
        p_UBSEC_ubsec_close(fd);

        num = p_UBSEC_ubsec_bits_to_bytes(num);
        meth = RAND_OpenSSL();
        meth->seed(buf, num);
        ret = meth->bytes(buf, num);

        goto err;
    }

    p_UBSEC_ubsec_close(fd);

    ret = 1;
 err:
    return (ret);
}

static int ubsec_rand_status(void)
{
    return 0;
}
#  endif

/*
 * 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_ubsec_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_UBSEC */
#endif                          /* !OPENSSL_NO_HW */