e_chil.c

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/* crypto/engine/e_chil.c -*- mode: C; c-file-style: "eay" -*- */
/* Written by Richard Levitte ([email protected]), Geoff Thorpe
 * ([email protected]) and Dr Stephen N Henson ([email protected])
 * 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

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

#ifndef OPENSSL_NO_HW
#ifndef OPENSSL_NO_HW_CHIL

/* Attribution notice: nCipher have said several times that it's OK for
 * us to implement a general interface to their boxes, and recently declared
 * their HWCryptoHook to be public, and therefore available for us to use.
 * Thanks, nCipher.
 *
 * The hwcryptohook.h included here is from May 2000.
 * [Richard Levitte]
 */
#ifdef FLAT_INC
#include "hwcryptohook.h"
#else
#include "vendor_defns/hwcryptohook.h"
#endif

#define HWCRHK_LIB_NAME "CHIL engine"
#include "e_chil_err.c"

static int hwcrhk_destroy(ENGINE *e);
static int hwcrhk_init(ENGINE *e);
static int hwcrhk_finish(ENGINE *e);
static int hwcrhk_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void)); 

/* Functions to handle mutexes */
static int hwcrhk_mutex_init(HWCryptoHook_Mutex*, HWCryptoHook_CallerContext*);
static int hwcrhk_mutex_lock(HWCryptoHook_Mutex*);
static void hwcrhk_mutex_unlock(HWCryptoHook_Mutex*);
static void hwcrhk_mutex_destroy(HWCryptoHook_Mutex*);

/* BIGNUM stuff */
static int hwcrhk_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
        const BIGNUM *m, BN_CTX *ctx);

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

#ifndef OPENSSL_NO_DH
/* DH stuff */
/* This function is alised to mod_exp (with the DH and mont dropped). */
static int hwcrhk_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 hwcrhk_rand_bytes(unsigned char *buf, int num);
static int hwcrhk_rand_status(void);

/* KM stuff */
static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
    UI_METHOD *ui_method, void *callback_data);
static EVP_PKEY *hwcrhk_load_pubkey(ENGINE *eng, const char *key_id,
    UI_METHOD *ui_method, void *callback_data);

/* Interaction stuff */
static int hwcrhk_insert_card(const char *prompt_info,
    const char *wrong_info,
    HWCryptoHook_PassphraseContext *ppctx,
    HWCryptoHook_CallerContext *cactx);
static int hwcrhk_get_pass(const char *prompt_info,
    int *len_io, char *buf,
    HWCryptoHook_PassphraseContext *ppctx,
    HWCryptoHook_CallerContext *cactx);
static void hwcrhk_log_message(void *logstr, const char *message);

/* The definitions for control commands specific to this engine */
#define HWCRHK_CMD_SO_PATH      ENGINE_CMD_BASE
#define HWCRHK_CMD_FORK_CHECK       (ENGINE_CMD_BASE + 1)
#define HWCRHK_CMD_THREAD_LOCKING   (ENGINE_CMD_BASE + 2)
#define HWCRHK_CMD_SET_USER_INTERFACE   (ENGINE_CMD_BASE + 3)
#define HWCRHK_CMD_SET_CALLBACK_DATA    (ENGINE_CMD_BASE + 4)
static const ENGINE_CMD_DEFN hwcrhk_cmd_defns[] = {
    {HWCRHK_CMD_SO_PATH,
        "SO_PATH",
        "Specifies the path to the 'hwcrhk' shared library",
        ENGINE_CMD_FLAG_STRING},
    {HWCRHK_CMD_FORK_CHECK,
        "FORK_CHECK",
        "Turns fork() checking on (non-zero) or off (zero)",
        ENGINE_CMD_FLAG_NUMERIC},
    {HWCRHK_CMD_THREAD_LOCKING,
        "THREAD_LOCKING",
        "Turns thread-safe locking on (zero) or off (non-zero)",
        ENGINE_CMD_FLAG_NUMERIC},
    {HWCRHK_CMD_SET_USER_INTERFACE,
        "SET_USER_INTERFACE",
        "Set the global user interface (internal)",
        ENGINE_CMD_FLAG_INTERNAL},
    {HWCRHK_CMD_SET_CALLBACK_DATA,
        "SET_CALLBACK_DATA",
        "Set the global user interface extra data (internal)",
        ENGINE_CMD_FLAG_INTERNAL},
    {0, NULL, NULL, 0}
    };

#ifndef OPENSSL_NO_RSA
/* Our internal RSA_METHOD that we provide pointers to */
static RSA_METHOD hwcrhk_rsa =
    {
    "CHIL RSA method",
    NULL,
    NULL,
    NULL,
    NULL,
    hwcrhk_rsa_mod_exp,
    hwcrhk_mod_exp_mont,
    NULL,
    hwcrhk_rsa_finish,
    0,
    NULL,
    NULL,
    NULL,
    NULL
    };
#endif

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

static RAND_METHOD hwcrhk_rand =
    {
    /* "CHIL RAND method", */
    NULL,
    hwcrhk_rand_bytes,
    NULL,
    NULL,
    hwcrhk_rand_bytes,
    hwcrhk_rand_status,
    };

/* Constants used when creating the ENGINE */
static const char *engine_hwcrhk_id = "chil";
static const char *engine_hwcrhk_name = "CHIL hardware engine support";
#ifndef OPENSSL_NO_DYNAMIC_ENGINE 
/* Compatibility hack, the dynamic library uses this form in the path */
static const char *engine_hwcrhk_id_alt = "ncipher";
#endif

/* Internal stuff for HWCryptoHook */

/* Some structures needed for proper use of thread locks */
/* hwcryptohook.h has some typedefs that turn struct HWCryptoHook_MutexValue
   into HWCryptoHook_Mutex */
struct HWCryptoHook_MutexValue
    {
    int lockid;
    };

/* hwcryptohook.h has some typedefs that turn
   struct HWCryptoHook_PassphraseContextValue
   into HWCryptoHook_PassphraseContext */
struct HWCryptoHook_PassphraseContextValue
    {
        UI_METHOD *ui_method;
    void *callback_data;
    };

/* hwcryptohook.h has some typedefs that turn
   struct HWCryptoHook_CallerContextValue
   into HWCryptoHook_CallerContext */
struct HWCryptoHook_CallerContextValue
    {
    pem_password_cb *password_callback; /* Deprecated!  Only present for
                                               backward compatibility! */
        UI_METHOD *ui_method;
    void *callback_data;
    };

/* The MPI structure in HWCryptoHook is pretty compatible with OpenSSL
   BIGNUM's, so lets define a couple of conversion macros */
#define BN2MPI(mp, bn) \
    {mp.size = bn->top * sizeof(BN_ULONG); mp.buf = (unsigned char *)bn->d;}
#define MPI2BN(bn, mp) \
    {mp.size = bn->dmax * sizeof(BN_ULONG); mp.buf = (unsigned char *)bn->d;}

static BIO *logstream = NULL;
static int disable_mutex_callbacks = 0;

/* One might wonder why these are needed, since one can pass down at least
   a UI_METHOD and a pointer to callback data to the key-loading functions.
   The thing is that the ModExp and RSAImmed functions can load keys as well,
   if the data they get is in a special, nCipher-defined format (hint: if you
   look at the private exponent of the RSA data as a string, you'll see this
   string: "nCipher KM tool key id", followed by some bytes, followed a key
   identity string, followed by more bytes.  This happens when you use "embed"
   keys instead of "hwcrhk" keys).  Unfortunately, those functions do not take
   any passphrase or caller context, and our functions can't really take any
   callback data either.  Still, the "insert_card" and "get_passphrase"
   callbacks may be called down the line, and will need to know what user
   interface callbacks to call, and having callback data from the application
   may be a nice thing as well, so we need to keep track of that globally. */
static HWCryptoHook_CallerContext password_context = { NULL, NULL, NULL };

/* Stuff to pass to the HWCryptoHook library */
static HWCryptoHook_InitInfo hwcrhk_globals = {
    HWCryptoHook_InitFlags_SimpleForkCheck, /* Flags */
    &logstream,     /* logstream */
    sizeof(BN_ULONG),   /* limbsize */
    0,          /* mslimb first: false for BNs */
    -1,         /* msbyte first: use native */
    0,          /* Max mutexes, 0 = no small limit */
    0,          /* Max simultaneous, 0 = default */

    /* The next few are mutex stuff: we write wrapper functions
       around the OS mutex functions.  We initialise them to 0
       here, and change that to actual function pointers in hwcrhk_init()
       if dynamic locks are supported (that is, if the application
       programmer has made sure of setting up callbacks bafore starting
       this engine) *and* if disable_mutex_callbacks hasn't been set by
       a call to ENGINE_ctrl(ENGINE_CTRL_CHIL_NO_LOCKING). */
    sizeof(HWCryptoHook_Mutex),
    0,
    0,
    0,
    0,

    /* The next few are condvar stuff: we write wrapper functions
       round the OS functions.  Currently not implemented and not
       and absolute necessity even in threaded programs, therefore
       0'ed.  Will hopefully be implemented some day, since it
       enhances the efficiency of HWCryptoHook.  */
    0, /* sizeof(HWCryptoHook_CondVar), */
    0, /* hwcrhk_cv_init, */
    0, /* hwcrhk_cv_wait, */
    0, /* hwcrhk_cv_signal, */
    0, /* hwcrhk_cv_broadcast, */
    0, /* hwcrhk_cv_destroy, */

    hwcrhk_get_pass,    /* pass phrase */
    hwcrhk_insert_card, /* insert a card */
    hwcrhk_log_message  /* Log message */
};


/* Now, to our own code */

/* This internal function is used by ENGINE_chil() 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_hwcrhk_id) ||
            !ENGINE_set_name(e, engine_hwcrhk_name) ||
#ifndef OPENSSL_NO_RSA
            !ENGINE_set_RSA(e, &hwcrhk_rsa) ||
#endif
#ifndef OPENSSL_NO_DH
            !ENGINE_set_DH(e, &hwcrhk_dh) ||
#endif
            !ENGINE_set_RAND(e, &hwcrhk_rand) ||
            !ENGINE_set_destroy_function(e, hwcrhk_destroy) ||
            !ENGINE_set_init_function(e, hwcrhk_init) ||
            !ENGINE_set_finish_function(e, hwcrhk_finish) ||
            !ENGINE_set_ctrl_function(e, hwcrhk_ctrl) ||
            !ENGINE_set_load_privkey_function(e, hwcrhk_load_privkey) ||
            !ENGINE_set_load_pubkey_function(e, hwcrhk_load_pubkey) ||
            !ENGINE_set_cmd_defns(e, hwcrhk_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();
    hwcrhk_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
    hwcrhk_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
    hwcrhk_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
    hwcrhk_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
#endif

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

    /* Ensure the hwcrhk error handling is set up */
    ERR_load_HWCRHK_strings();
    return 1;
    }

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

void ENGINE_load_chil(void)
    {
    /* Copied from eng_[openssl|dyn].c */
    ENGINE *toadd = engine_chil();
    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 HWCryptoHook 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 *hwcrhk_dso = NULL;
static HWCryptoHook_ContextHandle hwcrhk_context = 0;
#ifndef OPENSSL_NO_RSA
static int hndidx_rsa = -1;    /* Index for KM handle.  Not really used yet. */
#endif

/* These are the function pointers that are (un)set when the library has
 * successfully (un)loaded. */
static HWCryptoHook_Init_t *p_hwcrhk_Init = NULL;
static HWCryptoHook_Finish_t *p_hwcrhk_Finish = NULL;
static HWCryptoHook_ModExp_t *p_hwcrhk_ModExp = NULL;
#ifndef OPENSSL_NO_RSA
static HWCryptoHook_RSA_t *p_hwcrhk_RSA = NULL;
#endif
static HWCryptoHook_RandomBytes_t *p_hwcrhk_RandomBytes = NULL;
#ifndef OPENSSL_NO_RSA
static HWCryptoHook_RSALoadKey_t *p_hwcrhk_RSALoadKey = NULL;
static HWCryptoHook_RSAGetPublicKey_t *p_hwcrhk_RSAGetPublicKey = NULL;
static HWCryptoHook_RSAUnloadKey_t *p_hwcrhk_RSAUnloadKey = NULL;
#endif
static HWCryptoHook_ModExpCRT_t *p_hwcrhk_ModExpCRT = NULL;

/* Used in the DSO operations. */
static const char *HWCRHK_LIBNAME = NULL;
static void free_HWCRHK_LIBNAME(void)
    {
    if(HWCRHK_LIBNAME)
        OPENSSL_free((void*)HWCRHK_LIBNAME);
    HWCRHK_LIBNAME = NULL;
    }
static const char *get_HWCRHK_LIBNAME(void)
    {
    if(HWCRHK_LIBNAME)
        return HWCRHK_LIBNAME;
    return "nfhwcrhk";
    }
static long set_HWCRHK_LIBNAME(const char *name)
    {
    free_HWCRHK_LIBNAME();
    return (((HWCRHK_LIBNAME = BUF_strdup(name)) != NULL) ? 1 : 0);
    }
static const char *n_hwcrhk_Init = "HWCryptoHook_Init";
static const char *n_hwcrhk_Finish = "HWCryptoHook_Finish";
static const char *n_hwcrhk_ModExp = "HWCryptoHook_ModExp";
#ifndef OPENSSL_NO_RSA
static const char *n_hwcrhk_RSA = "HWCryptoHook_RSA";
#endif
static const char *n_hwcrhk_RandomBytes = "HWCryptoHook_RandomBytes";
#ifndef OPENSSL_NO_RSA
static const char *n_hwcrhk_RSALoadKey = "HWCryptoHook_RSALoadKey";
static const char *n_hwcrhk_RSAGetPublicKey = "HWCryptoHook_RSAGetPublicKey";
static const char *n_hwcrhk_RSAUnloadKey = "HWCryptoHook_RSAUnloadKey";
#endif
static const char *n_hwcrhk_ModExpCRT = "HWCryptoHook_ModExpCRT";

/* HWCryptoHook 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(HWCryptoHook_ContextHandle *hac,
        HWCryptoHook_CallerContext *cac)
    {
    char tempbuf[1024];
    HWCryptoHook_ErrMsgBuf rmsg;

    rmsg.buf = tempbuf;
    rmsg.size = sizeof(tempbuf);

        *hac = p_hwcrhk_Init(&hwcrhk_globals, sizeof(hwcrhk_globals), &rmsg,
        cac);
    if (!*hac)
                return 0;
        return 1;
    }
 
/* similarly to release one. */
static void release_context(HWCryptoHook_ContextHandle hac)
    {
    p_hwcrhk_Finish(hac);
    }

/* Destructor (complements the "ENGINE_chil()" constructor) */
static int hwcrhk_destroy(ENGINE *e)
    {
    free_HWCRHK_LIBNAME();
    ERR_unload_HWCRHK_strings();
    return 1;
    }

/* (de)initialisation functions. */
static int hwcrhk_init(ENGINE *e)
    {
    HWCryptoHook_Init_t *p1;
    HWCryptoHook_Finish_t *p2;
    HWCryptoHook_ModExp_t *p3;
#ifndef OPENSSL_NO_RSA
    HWCryptoHook_RSA_t *p4;
    HWCryptoHook_RSALoadKey_t *p5;
    HWCryptoHook_RSAGetPublicKey_t *p6;
    HWCryptoHook_RSAUnloadKey_t *p7;
#endif
    HWCryptoHook_RandomBytes_t *p8;
    HWCryptoHook_ModExpCRT_t *p9;

    if(hwcrhk_dso != NULL)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_INIT,HWCRHK_R_ALREADY_LOADED);
        goto err;
        }
    /* Attempt to load libnfhwcrhk.so/nfhwcrhk.dll/whatever. */
    hwcrhk_dso = DSO_load(NULL, get_HWCRHK_LIBNAME(), NULL, 0);
    if(hwcrhk_dso == NULL)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_INIT,HWCRHK_R_DSO_FAILURE);
        goto err;
        }
    if(!(p1 = (HWCryptoHook_Init_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_Init)) ||
        !(p2 = (HWCryptoHook_Finish_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_Finish)) ||
        !(p3 = (HWCryptoHook_ModExp_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_ModExp)) ||
#ifndef OPENSSL_NO_RSA
        !(p4 = (HWCryptoHook_RSA_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_RSA)) ||
        !(p5 = (HWCryptoHook_RSALoadKey_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_RSALoadKey)) ||
        !(p6 = (HWCryptoHook_RSAGetPublicKey_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_RSAGetPublicKey)) ||
        !(p7 = (HWCryptoHook_RSAUnloadKey_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_RSAUnloadKey)) ||
#endif
        !(p8 = (HWCryptoHook_RandomBytes_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_RandomBytes)) ||
        !(p9 = (HWCryptoHook_ModExpCRT_t *)
            DSO_bind_func(hwcrhk_dso, n_hwcrhk_ModExpCRT)))
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_INIT,HWCRHK_R_DSO_FAILURE);
        goto err;
        }
    /* Copy the pointers */
    p_hwcrhk_Init = p1;
    p_hwcrhk_Finish = p2;
    p_hwcrhk_ModExp = p3;
#ifndef OPENSSL_NO_RSA
    p_hwcrhk_RSA = p4;
    p_hwcrhk_RSALoadKey = p5;
    p_hwcrhk_RSAGetPublicKey = p6;
    p_hwcrhk_RSAUnloadKey = p7;
#endif
    p_hwcrhk_RandomBytes = p8;
    p_hwcrhk_ModExpCRT = p9;

    /* Check if the application decided to support dynamic locks,
       and if it does, use them. */
    if (disable_mutex_callbacks == 0)
        {
        if (CRYPTO_get_dynlock_create_callback() != NULL &&
            CRYPTO_get_dynlock_lock_callback() != NULL &&
            CRYPTO_get_dynlock_destroy_callback() != NULL)
            {
            hwcrhk_globals.mutex_init = hwcrhk_mutex_init;
            hwcrhk_globals.mutex_acquire = hwcrhk_mutex_lock;
            hwcrhk_globals.mutex_release = hwcrhk_mutex_unlock;
            hwcrhk_globals.mutex_destroy = hwcrhk_mutex_destroy;
            }
        }

    /* Try and get a context - if not, we may have a DSO but no
     * accelerator! */
    if(!get_context(&hwcrhk_context, &password_context))
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_INIT,HWCRHK_R_UNIT_FAILURE);
        goto err;
        }
    /* Everything's fine. */
#ifndef OPENSSL_NO_RSA
    if (hndidx_rsa == -1)
        hndidx_rsa = RSA_get_ex_new_index(0,
            "nFast HWCryptoHook RSA key handle",
            NULL, NULL, NULL);
#endif
    return 1;
err:
    if(hwcrhk_dso)
        DSO_free(hwcrhk_dso);
    hwcrhk_dso = NULL;
    p_hwcrhk_Init = NULL;
    p_hwcrhk_Finish = NULL;
    p_hwcrhk_ModExp = NULL;
#ifndef OPENSSL_NO_RSA
    p_hwcrhk_RSA = NULL;
    p_hwcrhk_RSALoadKey = NULL;
    p_hwcrhk_RSAGetPublicKey = NULL;
    p_hwcrhk_RSAUnloadKey = NULL;
#endif
    p_hwcrhk_ModExpCRT = NULL;
    p_hwcrhk_RandomBytes = NULL;
    return 0;
    }

static int hwcrhk_finish(ENGINE *e)
    {
    int to_return = 1;
    free_HWCRHK_LIBNAME();
    if(hwcrhk_dso == NULL)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_FINISH,HWCRHK_R_NOT_LOADED);
        to_return = 0;
        goto err;
        }
    release_context(hwcrhk_context);
    if(!DSO_free(hwcrhk_dso))
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_FINISH,HWCRHK_R_DSO_FAILURE);
        to_return = 0;
        goto err;
        }
 err:
    if (logstream)
        BIO_free(logstream);
    hwcrhk_dso = NULL;
    p_hwcrhk_Init = NULL;
    p_hwcrhk_Finish = NULL;
    p_hwcrhk_ModExp = NULL;
#ifndef OPENSSL_NO_RSA
    p_hwcrhk_RSA = NULL;
    p_hwcrhk_RSALoadKey = NULL;
    p_hwcrhk_RSAGetPublicKey = NULL;
    p_hwcrhk_RSAUnloadKey = NULL;
#endif
    p_hwcrhk_ModExpCRT = NULL;
    p_hwcrhk_RandomBytes = NULL;
    return to_return;
    }

static int hwcrhk_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void))
    {
    int to_return = 1;

    switch(cmd)
        {
    case HWCRHK_CMD_SO_PATH:
        if(hwcrhk_dso)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_CTRL,HWCRHK_R_ALREADY_LOADED);
            return 0;
            }
        if(p == NULL)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_CTRL,ERR_R_PASSED_NULL_PARAMETER);
            return 0;
            }
        return set_HWCRHK_LIBNAME((const char *)p);
    case ENGINE_CTRL_SET_LOGSTREAM:
        {
        BIO *bio = (BIO *)p;

        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        if (logstream)
            {
            BIO_free(logstream);
            logstream = NULL;
            }
        if (CRYPTO_add(&bio->references,1,CRYPTO_LOCK_BIO) > 1)
            logstream = bio;
        else
            HWCRHKerr(HWCRHK_F_HWCRHK_CTRL,HWCRHK_R_BIO_WAS_FREED);
        }
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    case ENGINE_CTRL_SET_PASSWORD_CALLBACK:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        password_context.password_callback = (pem_password_cb *)f;
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    case ENGINE_CTRL_SET_USER_INTERFACE:
    case HWCRHK_CMD_SET_USER_INTERFACE:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        password_context.ui_method = (UI_METHOD *)p;
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    case ENGINE_CTRL_SET_CALLBACK_DATA:
    case HWCRHK_CMD_SET_CALLBACK_DATA:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        password_context.callback_data = p;
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    /* this enables or disables the "SimpleForkCheck" flag used in the
     * initialisation structure. */
    case ENGINE_CTRL_CHIL_SET_FORKCHECK:
    case HWCRHK_CMD_FORK_CHECK:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        if(i)
            hwcrhk_globals.flags |=
                HWCryptoHook_InitFlags_SimpleForkCheck;
        else
            hwcrhk_globals.flags &=
                ~HWCryptoHook_InitFlags_SimpleForkCheck;
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    /* This will prevent the initialisation function from "installing"
     * the mutex-handling callbacks, even if they are available from
     * within the library (or were provided to the library from the
     * calling application). This is to remove any baggage for
     * applications not using multithreading. */
    case ENGINE_CTRL_CHIL_NO_LOCKING:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        disable_mutex_callbacks = 1;
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;
    case HWCRHK_CMD_THREAD_LOCKING:
        CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
        disable_mutex_callbacks = ((i == 0) ? 0 : 1);
        CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
        break;

    /* The command isn't understood by this engine */
    default:
        HWCRHKerr(HWCRHK_F_HWCRHK_CTRL,
            HWCRHK_R_CTRL_COMMAND_NOT_IMPLEMENTED);
        to_return = 0;
        break;
        }

    return to_return;
    }

static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
    UI_METHOD *ui_method, void *callback_data)
    {
#ifndef OPENSSL_NO_RSA
    RSA *rtmp = NULL;
#endif
    EVP_PKEY *res = NULL;
#ifndef OPENSSL_NO_RSA
    HWCryptoHook_MPI e, n;
    HWCryptoHook_RSAKeyHandle *hptr;
#endif
#if !defined(OPENSSL_NO_RSA)
    char tempbuf[1024];
    HWCryptoHook_ErrMsgBuf rmsg;
    HWCryptoHook_PassphraseContext ppctx;
#endif

#if !defined(OPENSSL_NO_RSA)
    rmsg.buf = tempbuf;
    rmsg.size = sizeof(tempbuf);
#endif

    if(!hwcrhk_context)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
            HWCRHK_R_NOT_INITIALISED);
        goto err;
        }
#ifndef OPENSSL_NO_RSA
    hptr = OPENSSL_malloc(sizeof(HWCryptoHook_RSAKeyHandle));
    if (!hptr)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
            ERR_R_MALLOC_FAILURE);
        goto err;
        }
        ppctx.ui_method = ui_method;
    ppctx.callback_data = callback_data;
    if (p_hwcrhk_RSALoadKey(hwcrhk_context, key_id, hptr,
        &rmsg, &ppctx))
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
            HWCRHK_R_CHIL_ERROR);
        ERR_add_error_data(1,rmsg.buf);
        goto err;
        }
    if (!*hptr)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
            HWCRHK_R_NO_KEY);
        goto err;
        }
#endif
#ifndef OPENSSL_NO_RSA
    rtmp = RSA_new_method(eng);
    RSA_set_ex_data(rtmp, hndidx_rsa, (char *)hptr);
    rtmp->e = BN_new();
    rtmp->n = BN_new();
    rtmp->flags |= RSA_FLAG_EXT_PKEY;
    MPI2BN(rtmp->e, e);
    MPI2BN(rtmp->n, n);
    if (p_hwcrhk_RSAGetPublicKey(*hptr, &n, &e, &rmsg)
        != HWCRYPTOHOOK_ERROR_MPISIZE)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,HWCRHK_R_CHIL_ERROR);
        ERR_add_error_data(1,rmsg.buf);
        goto err;
        }

    bn_expand2(rtmp->e, e.size/sizeof(BN_ULONG));
    bn_expand2(rtmp->n, n.size/sizeof(BN_ULONG));
    MPI2BN(rtmp->e, e);
    MPI2BN(rtmp->n, n);

    if (p_hwcrhk_RSAGetPublicKey(*hptr, &n, &e, &rmsg))
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
            HWCRHK_R_CHIL_ERROR);
        ERR_add_error_data(1,rmsg.buf);
        goto err;
        }
    rtmp->e->top = e.size / sizeof(BN_ULONG);
    bn_fix_top(rtmp->e);
    rtmp->n->top = n.size / sizeof(BN_ULONG);
    bn_fix_top(rtmp->n);

    res = EVP_PKEY_new();
    EVP_PKEY_assign_RSA(res, rtmp);
#endif

        if (!res)
                HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PRIVKEY,
                        HWCRHK_R_PRIVATE_KEY_ALGORITHMS_DISABLED);

    return res;
 err:
#ifndef OPENSSL_NO_RSA
    if (rtmp)
        RSA_free(rtmp);
#endif
    return NULL;
    }

static EVP_PKEY *hwcrhk_load_pubkey(ENGINE *eng, const char *key_id,
    UI_METHOD *ui_method, void *callback_data)
    {
    EVP_PKEY *res = NULL;

#ifndef OPENSSL_NO_RSA
        res = hwcrhk_load_privkey(eng, key_id,
                ui_method, callback_data);
#endif

    if (res)
        switch(res->type)
            {
#ifndef OPENSSL_NO_RSA
        case EVP_PKEY_RSA:
            {
            RSA *rsa = NULL;

            CRYPTO_w_lock(CRYPTO_LOCK_EVP_PKEY);
            rsa = res->pkey.rsa;
            res->pkey.rsa = RSA_new();
            res->pkey.rsa->n = rsa->n;
            res->pkey.rsa->e = rsa->e;
            rsa->n = NULL;
            rsa->e = NULL;
            CRYPTO_w_unlock(CRYPTO_LOCK_EVP_PKEY);
            RSA_free(rsa);
            }
            break;
#endif
        default:
            HWCRHKerr(HWCRHK_F_HWCRHK_LOAD_PUBKEY,
                HWCRHK_R_CTRL_COMMAND_NOT_IMPLEMENTED);
            goto err;
            }

    return res;
 err:
    if (res)
        EVP_PKEY_free(res);
    return NULL;
    }

/* A little mod_exp */
static int hwcrhk_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
            const BIGNUM *m, BN_CTX *ctx)
    {
    char tempbuf[1024];
    HWCryptoHook_ErrMsgBuf rmsg;
    /* Since HWCryptoHook_MPI is pretty compatible with BIGNUM's,
       we use them directly, plus a little macro magic.  We only
       thing we need to make sure of is that enough space is allocated. */
    HWCryptoHook_MPI m_a, m_p, m_n, m_r;
    int to_return, ret;
 
    to_return = 0; /* expect failure */
    rmsg.buf = tempbuf;
    rmsg.size = sizeof(tempbuf);

    if(!hwcrhk_context)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_MOD_EXP,HWCRHK_R_NOT_INITIALISED);
        goto err;
        }
    /* Prepare the params */
    bn_expand2(r, m->top);  /* Check for error !! */
    BN2MPI(m_a, a);
    BN2MPI(m_p, p);
    BN2MPI(m_n, m);
    MPI2BN(r, m_r);

    /* Perform the operation */
    ret = p_hwcrhk_ModExp(hwcrhk_context, m_a, m_p, m_n, &m_r, &rmsg);

    /* Convert the response */
    r->top = m_r.size / sizeof(BN_ULONG);
    bn_fix_top(r);

    if (ret < 0)
        {
        /* FIXME: When this error is returned, HWCryptoHook is
           telling us that falling back to software computation
           might be a good thing. */
        if(ret == HWCRYPTOHOOK_ERROR_FALLBACK)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_MOD_EXP,HWCRHK_R_REQUEST_FALLBACK);
            }
        else
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_MOD_EXP,HWCRHK_R_REQUEST_FAILED);
            }
        ERR_add_error_data(1,rmsg.buf);
        goto err;
        }

    to_return = 1;
err:
    return to_return;
    }

#ifndef OPENSSL_NO_RSA 
static int hwcrhk_rsa_mod_exp(BIGNUM *r, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
    {
    char tempbuf[1024];
    HWCryptoHook_ErrMsgBuf rmsg;
    HWCryptoHook_RSAKeyHandle *hptr;
    int to_return = 0, ret;

    rmsg.buf = tempbuf;
    rmsg.size = sizeof(tempbuf);

    if(!hwcrhk_context)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,HWCRHK_R_NOT_INITIALISED);
        goto err;
        }

    /* This provides support for nForce keys.  Since that's opaque data
       all we do is provide a handle to the proper key and let HWCryptoHook
       take care of the rest. */
    if ((hptr = (HWCryptoHook_RSAKeyHandle *) RSA_get_ex_data(rsa, hndidx_rsa))
        != NULL)
        {
        HWCryptoHook_MPI m_a, m_r;

        if(!rsa->n)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                HWCRHK_R_MISSING_KEY_COMPONENTS);
            goto err;
            }

        /* Prepare the params */
        bn_expand2(r, rsa->n->top); /* Check for error !! */
        BN2MPI(m_a, I);
        MPI2BN(r, m_r);

        /* Perform the operation */
        ret = p_hwcrhk_RSA(m_a, *hptr, &m_r, &rmsg);

        /* Convert the response */
        r->top = m_r.size / sizeof(BN_ULONG);
        bn_fix_top(r);

        if (ret < 0)
            {
            /* FIXME: When this error is returned, HWCryptoHook is
               telling us that falling back to software computation
               might be a good thing. */
            if(ret == HWCRYPTOHOOK_ERROR_FALLBACK)
                {
                HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                    HWCRHK_R_REQUEST_FALLBACK);
                }
            else
                {
                HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                    HWCRHK_R_REQUEST_FAILED);
                }
            ERR_add_error_data(1,rmsg.buf);
            goto err;
            }
        }
    else
        {
        HWCryptoHook_MPI m_a, m_p, m_q, m_dmp1, m_dmq1, m_iqmp, m_r;

        if(!rsa->p || !rsa->q || !rsa->dmp1 || !rsa->dmq1 || !rsa->iqmp)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                HWCRHK_R_MISSING_KEY_COMPONENTS);
            goto err;
            }

        /* Prepare the params */
        bn_expand2(r, rsa->n->top); /* Check for error !! */
        BN2MPI(m_a, I);
        BN2MPI(m_p, rsa->p);
        BN2MPI(m_q, rsa->q);
        BN2MPI(m_dmp1, rsa->dmp1);
        BN2MPI(m_dmq1, rsa->dmq1);
        BN2MPI(m_iqmp, rsa->iqmp);
        MPI2BN(r, m_r);

        /* Perform the operation */
        ret = p_hwcrhk_ModExpCRT(hwcrhk_context, m_a, m_p, m_q,
            m_dmp1, m_dmq1, m_iqmp, &m_r, &rmsg);

        /* Convert the response */
        r->top = m_r.size / sizeof(BN_ULONG);
        bn_fix_top(r);

        if (ret < 0)
            {
            /* FIXME: When this error is returned, HWCryptoHook is
               telling us that falling back to software computation
               might be a good thing. */
            if(ret == HWCRYPTOHOOK_ERROR_FALLBACK)
                {
                HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                    HWCRHK_R_REQUEST_FALLBACK);
                }
            else
                {
                HWCRHKerr(HWCRHK_F_HWCRHK_RSA_MOD_EXP,
                    HWCRHK_R_REQUEST_FAILED);
                }
            ERR_add_error_data(1,rmsg.buf);
            goto err;
            }
        }
    /* If we're here, we must be here with some semblance of success :-) */
    to_return = 1;
err:
    return to_return;
    }
#endif

#ifndef OPENSSL_NO_RSA
/* This function is aliased to mod_exp (with the mont stuff dropped). */
static int hwcrhk_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
        const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
    {
    return hwcrhk_mod_exp(r, a, p, m, ctx);
    }

static int hwcrhk_rsa_finish(RSA *rsa)
    {
    HWCryptoHook_RSAKeyHandle *hptr;

    hptr = RSA_get_ex_data(rsa, hndidx_rsa);
    if (hptr)
                {
                p_hwcrhk_RSAUnloadKey(*hptr, NULL);
                OPENSSL_free(hptr);
        RSA_set_ex_data(rsa, hndidx_rsa, NULL);
                }
    return 1;
    }

#endif

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

/* Random bytes are good */
static int hwcrhk_rand_bytes(unsigned char *buf, int num)
    {
    char tempbuf[1024];
    HWCryptoHook_ErrMsgBuf rmsg;
    int to_return = 0; /* assume failure */
    int ret;

    rmsg.buf = tempbuf;
    rmsg.size = sizeof(tempbuf);

    if(!hwcrhk_context)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_RAND_BYTES,HWCRHK_R_NOT_INITIALISED);
        goto err;
        }

    ret = p_hwcrhk_RandomBytes(hwcrhk_context, buf, num, &rmsg);
    if (ret < 0)
        {
        /* FIXME: When this error is returned, HWCryptoHook is
           telling us that falling back to software computation
           might be a good thing. */
        if(ret == HWCRYPTOHOOK_ERROR_FALLBACK)
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_RAND_BYTES,
                HWCRHK_R_REQUEST_FALLBACK);
            }
        else
            {
            HWCRHKerr(HWCRHK_F_HWCRHK_RAND_BYTES,
                HWCRHK_R_REQUEST_FAILED);
            }
        ERR_add_error_data(1,rmsg.buf);
        goto err;
        }
    to_return = 1;
 err:
    return to_return;
    }

static int hwcrhk_rand_status(void)
    {
    return 1;
    }

/* Mutex calls: since the HWCryptoHook model closely follows the POSIX model
 * these just wrap the POSIX functions and add some logging.
 */

static int hwcrhk_mutex_init(HWCryptoHook_Mutex* mt,
    HWCryptoHook_CallerContext *cactx)
    {
    mt->lockid = CRYPTO_get_new_dynlockid();
    if (mt->lockid == 0)
        return 1; /* failure */
    return 0; /* success */
    }

static int hwcrhk_mutex_lock(HWCryptoHook_Mutex *mt)
    {
    CRYPTO_w_lock(mt->lockid);
    return 0;
    }

static void hwcrhk_mutex_unlock(HWCryptoHook_Mutex * mt)
    {
    CRYPTO_w_unlock(mt->lockid);
    }

static void hwcrhk_mutex_destroy(HWCryptoHook_Mutex *mt)
    {
    CRYPTO_destroy_dynlockid(mt->lockid);
    }

static int hwcrhk_get_pass(const char *prompt_info,
    int *len_io, char *buf,
    HWCryptoHook_PassphraseContext *ppctx,
    HWCryptoHook_CallerContext *cactx)
    {
    pem_password_cb *callback = NULL;
    void *callback_data = NULL;
        UI_METHOD *ui_method = NULL;
    /* Despite what the documentation says prompt_info can be
     * an empty string.
     */
    if (prompt_info && !*prompt_info)
        prompt_info = NULL;

        if (cactx)
                {
                if (cactx->ui_method)
                        ui_method = cactx->ui_method;
        if (cactx->password_callback)
            callback = cactx->password_callback;
        if (cactx->callback_data)
            callback_data = cactx->callback_data;
                }
    if (ppctx)
        {
                if (ppctx->ui_method)
                        {
                        ui_method = ppctx->ui_method;
                        callback = NULL;
                        }
        if (ppctx->callback_data)
            callback_data = ppctx->callback_data;
        }
    if (callback == NULL && ui_method == NULL)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_GET_PASS,HWCRHK_R_NO_CALLBACK);
        return -1;
        }

        if (ui_method)
                {
                UI *ui = UI_new_method(ui_method);
                if (ui)
                        {
                        int ok;
                        char *prompt = UI_construct_prompt(ui,
                                "pass phrase", prompt_info);

                        ok = UI_add_input_string(ui,prompt,
                                UI_INPUT_FLAG_DEFAULT_PWD,
                buf,0,(*len_io) - 1);
                        UI_add_user_data(ui, callback_data);
            UI_ctrl(ui, UI_CTRL_PRINT_ERRORS, 1, 0, 0);

            if (ok >= 0)
                do
                    {
                    ok=UI_process(ui);
                    }
                while (ok < 0 && UI_ctrl(ui, UI_CTRL_IS_REDOABLE, 0, 0, 0));

                        if (ok >= 0)
                                *len_io = strlen(buf);

                        UI_free(ui);
                        OPENSSL_free(prompt);
                        }
                }
        else
                {
                *len_io = callback(buf, *len_io, 0, callback_data);
                }
    if(!*len_io)
        return -1;
    return 0;
    }

static int hwcrhk_insert_card(const char *prompt_info,
              const char *wrong_info,
              HWCryptoHook_PassphraseContext *ppctx,
              HWCryptoHook_CallerContext *cactx)
        {
        int ok = -1;
        UI *ui;
    void *callback_data = NULL;
        UI_METHOD *ui_method = NULL;

        if (cactx)
                {
                if (cactx->ui_method)
                        ui_method = cactx->ui_method;
        if (cactx->callback_data)
            callback_data = cactx->callback_data;
                }
    if (ppctx)
        {
                if (ppctx->ui_method)
                        ui_method = ppctx->ui_method;
        if (ppctx->callback_data)
            callback_data = ppctx->callback_data;
        }
    if (ui_method == NULL)
        {
        HWCRHKerr(HWCRHK_F_HWCRHK_INSERT_CARD,
            HWCRHK_R_NO_CALLBACK);
        return -1;
        }

    ui = UI_new_method(ui_method);

    if (ui)
        {
        char answer;
        char buf[BUFSIZ];
        /* Despite what the documentation says wrong_info can be
         * an empty string.
         */
        if (wrong_info && *wrong_info)
            BIO_snprintf(buf, sizeof(buf)-1,
                "Current card: \"%s\"\n", wrong_info);
        else
            buf[0] = 0;
        ok = UI_dup_info_string(ui, buf);
        if (ok >= 0 && prompt_info)
            {
            BIO_snprintf(buf, sizeof(buf)-1,
                "Insert card \"%s\"", prompt_info);
            ok = UI_dup_input_boolean(ui, buf,
                "\n then hit <enter> or C<enter> to cancel\n",
                "\r\n", "Cc", UI_INPUT_FLAG_ECHO, &answer);
            }
        UI_add_user_data(ui, callback_data);

        if (ok >= 0)
            ok = UI_process(ui);
        UI_free(ui);

        if (ok == -2 || (ok >= 0 && answer == 'C'))
            ok = 1;
        else if (ok < 0)
            ok = -1;
        else
            ok = 0;
        }
    return ok;
    }

static void hwcrhk_log_message(void *logstr, const char *message)
    {
    BIO *lstream = NULL;

    CRYPTO_w_lock(CRYPTO_LOCK_BIO);
    if (logstr)
        lstream=*(BIO **)logstr;
    if (lstream)
        {
        BIO_printf(lstream, "%s\n", message);
        }
    CRYPTO_w_unlock(CRYPTO_LOCK_BIO);
    }

/* 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_hwcrhk_id) != 0) &&
            (strcmp(id, engine_hwcrhk_id_alt) != 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_CHIL */
#endif /* !OPENSSL_NO_HW */