Make more use of OSSL_PARAM for digests

[thirdparty/openssl.git] / crypto / evp / evp_lib.c

/*
 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include <openssl/dh.h>
#include "internal/evp_int.h"
#include "internal/provider.h"
#include "evp_locl.h"

#if !defined(FIPS_MODE)
int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type)
{
    int ret;
    const EVP_CIPHER *cipher = c->cipher;

    if (cipher->prov != NULL) {
        /*
         * The cipher has come from a provider and won't have the default flags.
         * Find the implicit form so we can check the flags.
         * TODO(3.0): This won't work for 3rd party ciphers we know nothing about
         * We'll need to think of something else for those.
         */
        cipher = EVP_get_cipherbynid(cipher->nid);
        if (cipher == NULL) {
            EVPerr(EVP_F_EVP_CIPHER_PARAM_TO_ASN1, ASN1_R_UNSUPPORTED_CIPHER);
            return -1;
        }
    }

    if (cipher->set_asn1_parameters != NULL)
        ret = cipher->set_asn1_parameters(c, type);
    else if (cipher->flags & EVP_CIPH_FLAG_DEFAULT_ASN1) {
        switch (EVP_CIPHER_mode(cipher)) {
        case EVP_CIPH_WRAP_MODE:
            if (EVP_CIPHER_nid(cipher) == NID_id_smime_alg_CMS3DESwrap)
                ASN1_TYPE_set(type, V_ASN1_NULL, NULL);
            ret = 1;
            break;

        case EVP_CIPH_GCM_MODE:
        case EVP_CIPH_CCM_MODE:
        case EVP_CIPH_XTS_MODE:
        case EVP_CIPH_OCB_MODE:
            ret = -2;
            break;

        default:
            ret = EVP_CIPHER_set_asn1_iv(c, type);
        }
    } else
        ret = -1;
    if (ret <= 0)
        EVPerr(EVP_F_EVP_CIPHER_PARAM_TO_ASN1, ret == -2 ?
               ASN1_R_UNSUPPORTED_CIPHER :
               EVP_R_CIPHER_PARAMETER_ERROR);
    if (ret < -1)
        ret = -1;
    return ret;
}

int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type)
{
    int ret;
    const EVP_CIPHER *cipher = c->cipher;

    if (cipher->prov != NULL) {
        /*
         * The cipher has come from a provider and won't have the default flags.
         * Find the implicit form so we can check the flags.
         */
        cipher = EVP_get_cipherbynid(cipher->nid);
        if (cipher == NULL)
            return -1;
    }

    if (cipher->get_asn1_parameters != NULL)
        ret = cipher->get_asn1_parameters(c, type);
    else if (cipher->flags & EVP_CIPH_FLAG_DEFAULT_ASN1) {
        switch (EVP_CIPHER_mode(cipher)) {

        case EVP_CIPH_WRAP_MODE:
            ret = 1;
            break;

        case EVP_CIPH_GCM_MODE:
        case EVP_CIPH_CCM_MODE:
        case EVP_CIPH_XTS_MODE:
        case EVP_CIPH_OCB_MODE:
            ret = -2;
            break;

        default:
            ret = EVP_CIPHER_get_asn1_iv(c, type);
            break;
        }
    } else
        ret = -1;
    if (ret <= 0)
        EVPerr(EVP_F_EVP_CIPHER_ASN1_TO_PARAM, ret == -2 ?
               EVP_R_UNSUPPORTED_CIPHER :
               EVP_R_CIPHER_PARAMETER_ERROR);
    if (ret < -1)
        ret = -1;
    return ret;
}

int EVP_CIPHER_get_asn1_iv(EVP_CIPHER_CTX *ctx, ASN1_TYPE *type)
{
    int i = 0;
    unsigned int l;

    if (type != NULL) {
        unsigned char iv[EVP_MAX_IV_LENGTH];

        l = EVP_CIPHER_CTX_iv_length(ctx);
        if (!ossl_assert(l <= sizeof(iv)))
            return -1;
        i = ASN1_TYPE_get_octetstring(type, iv, l);
        if (i != (int)l)
            return -1;

        if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, -1))
            return -1;
    }
    return i;
}

int EVP_CIPHER_set_asn1_iv(EVP_CIPHER_CTX *c, ASN1_TYPE *type)
{
    int i = 0;
    unsigned int j;

    if (type != NULL) {
        j = EVP_CIPHER_CTX_iv_length(c);
        OPENSSL_assert(j <= sizeof(c->iv));
        i = ASN1_TYPE_set_octetstring(type, c->oiv, j);
    }
    return i;
}
#endif /* !defined(FIPS_MODE) */

/* Convert the various cipher NIDs and dummies to a proper OID NID */
int EVP_CIPHER_type(const EVP_CIPHER *ctx)
{
    int nid;
    nid = EVP_CIPHER_nid(ctx);

    switch (nid) {

    case NID_rc2_cbc:
    case NID_rc2_64_cbc:
    case NID_rc2_40_cbc:

        return NID_rc2_cbc;

    case NID_rc4:
    case NID_rc4_40:

        return NID_rc4;

    case NID_aes_128_cfb128:
    case NID_aes_128_cfb8:
    case NID_aes_128_cfb1:

        return NID_aes_128_cfb128;

    case NID_aes_192_cfb128:
    case NID_aes_192_cfb8:
    case NID_aes_192_cfb1:

        return NID_aes_192_cfb128;

    case NID_aes_256_cfb128:
    case NID_aes_256_cfb8:
    case NID_aes_256_cfb1:

        return NID_aes_256_cfb128;

    case NID_des_cfb64:
    case NID_des_cfb8:
    case NID_des_cfb1:

        return NID_des_cfb64;

    case NID_des_ede3_cfb64:
    case NID_des_ede3_cfb8:
    case NID_des_ede3_cfb1:

        return NID_des_cfb64;

    default:
#ifdef FIPS_MODE
        return NID_undef;
#else
        {
            /* Check it has an OID and it is valid */
            ASN1_OBJECT *otmp = OBJ_nid2obj(nid);

            if (OBJ_get0_data(otmp) == NULL)
                nid = NID_undef;
            ASN1_OBJECT_free(otmp);
            return nid;
        }
#endif
    }
}

int EVP_CIPHER_block_size(const EVP_CIPHER *cipher)
{
    int ok, v = cipher->block_size;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_BLOCK_SIZE, &v);
    ok = evp_do_ciph_getparams(cipher, params);

    return ok != 0 ? v : EVP_CTRL_RET_UNSUPPORTED;
}

int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx)
{
    return EVP_CIPHER_block_size(ctx->cipher);
}

int EVP_CIPHER_impl_ctx_size(const EVP_CIPHER *e)
{
    return e->ctx_size;
}

int EVP_Cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
               const unsigned char *in, unsigned int inl)
{
    if (ctx->cipher->prov != NULL) {
        size_t outl = 0;         /* ignored */
        int blocksize = EVP_CIPHER_CTX_block_size(ctx);

        if (ctx->cipher->ccipher != NULL)
            return
                ctx->cipher->ccipher(ctx->provctx, out, &outl,
                                     inl + (blocksize == 1 ? 0 : blocksize),
                                     in, (size_t)inl);
        return 0;
    }

    return ctx->cipher->do_cipher(ctx, out, in, inl);
}

const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx)
{
    return ctx->cipher;
}

int EVP_CIPHER_CTX_encrypting(const EVP_CIPHER_CTX *ctx)
{
    return ctx->encrypt;
}

unsigned long EVP_CIPHER_flags(const EVP_CIPHER *cipher)
{
    int ok;
    unsigned long v = cipher->flags;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_ulong(OSSL_CIPHER_PARAM_FLAGS, &v);
    ok = evp_do_ciph_getparams(cipher, params);

    return ok != 0 ? v : 0;
}

void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx)
{
    return ctx->app_data;
}

void EVP_CIPHER_CTX_set_app_data(EVP_CIPHER_CTX *ctx, void *data)
{
    ctx->app_data = data;
}

void *EVP_CIPHER_CTX_get_cipher_data(const EVP_CIPHER_CTX *ctx)
{
    return ctx->cipher_data;
}

void *EVP_CIPHER_CTX_set_cipher_data(EVP_CIPHER_CTX *ctx, void *cipher_data)
{
    void *old_cipher_data;

    old_cipher_data = ctx->cipher_data;
    ctx->cipher_data = cipher_data;

    return old_cipher_data;
}

int EVP_CIPHER_iv_length(const EVP_CIPHER *cipher)
{
    int ok, v = cipher->iv_len;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_IVLEN, &v);
    ok = evp_do_ciph_getparams(cipher, params);

    return ok != 0 ? v : EVP_CTRL_RET_UNSUPPORTED;
}

int EVP_CIPHER_CTX_iv_length(const EVP_CIPHER_CTX *ctx)
{
    int len, rv, v = EVP_CIPHER_iv_length(ctx->cipher);
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_IVLEN, &v);
    rv = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);
    if (rv == EVP_CTRL_RET_UNSUPPORTED)
        goto legacy;
    return rv != 0 ? v : -1;
    /* TODO (3.0) Remove legacy support */
legacy:
    if ((EVP_CIPHER_flags(ctx->cipher) & EVP_CIPH_CUSTOM_IV_LENGTH) != 0) {
        rv = EVP_CIPHER_CTX_ctrl((EVP_CIPHER_CTX *)ctx, EVP_CTRL_GET_IVLEN,
                                 0, &len);
        return (rv == 1) ? len : -1;
    }
    return v;
}

const unsigned char *EVP_CIPHER_CTX_original_iv(const EVP_CIPHER_CTX *ctx)
{
    return ctx->oiv;
}

/*
 * OSSL_PARAM_OCTET_PTR gets us the pointer to the running IV in the provider
 */
const unsigned char *EVP_CIPHER_CTX_iv(const EVP_CIPHER_CTX *ctx)
{
    int ok;
    const unsigned char *v = ctx->iv;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] =
        OSSL_PARAM_construct_octet_ptr(OSSL_CIPHER_PARAM_IV, (void **)&v,
                                       sizeof(ctx->iv));
    ok = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);

    return ok != 0 ? v : NULL;
}

unsigned char *EVP_CIPHER_CTX_iv_noconst(EVP_CIPHER_CTX *ctx)
{
    int ok;
    unsigned char *v = ctx->iv;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] =
        OSSL_PARAM_construct_octet_ptr(OSSL_CIPHER_PARAM_IV, (void **)&v,
                                       sizeof(ctx->iv));
    ok = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);

    return ok != 0 ? v : NULL;
}

unsigned char *EVP_CIPHER_CTX_buf_noconst(EVP_CIPHER_CTX *ctx)
{
    return ctx->buf;
}

int EVP_CIPHER_CTX_num(const EVP_CIPHER_CTX *ctx)
{
    int ok, v = ctx->num;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_NUM, &v);
    ok = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);

    return ok != 0 ? v : EVP_CTRL_RET_UNSUPPORTED;
}

int EVP_CIPHER_CTX_set_num(EVP_CIPHER_CTX *ctx, int num)
{
    int ok;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_NUM, &num);
    ok = evp_do_ciph_ctx_setparams(ctx->cipher, ctx->provctx, params);

    if (ok != 0)
        ctx->num = num;
    return ok != 0;
}

int EVP_CIPHER_key_length(const EVP_CIPHER *cipher)
{
    int ok, v = cipher->key_len;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_KEYLEN, &v);
    ok = evp_do_ciph_getparams(cipher, params);

    return ok != 0 ? v : EVP_CTRL_RET_UNSUPPORTED;
}

int EVP_CIPHER_CTX_key_length(const EVP_CIPHER_CTX *ctx)
{
    int ok, v = ctx->key_len;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_KEYLEN, &v);
    ok = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);

    return ok != 0 ? v : EVP_CTRL_RET_UNSUPPORTED;
}

int EVP_CIPHER_nid(const EVP_CIPHER *cipher)
{
    return cipher->nid;
}

int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx)
{
    return ctx->cipher->nid;
}

const char *EVP_CIPHER_name(const EVP_CIPHER *cipher)
{
    if (cipher->prov != NULL)
        return cipher->name;
#ifndef FIPS_MODE
    return OBJ_nid2sn(EVP_CIPHER_nid(cipher));
#else
    return NULL;
#endif
}

const OSSL_PROVIDER *EVP_CIPHER_provider(const EVP_CIPHER *cipher)
{
    return cipher->prov;
}

int EVP_CIPHER_mode(const EVP_CIPHER *cipher)
{
    int ok, v = EVP_CIPHER_flags(cipher) & EVP_CIPH_MODE;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_int(OSSL_CIPHER_PARAM_MODE, &v);
    ok = evp_do_ciph_getparams(cipher, params);

    return ok != 0 ? v : 0;
}

const char *EVP_MD_name(const EVP_MD *md)
{
    if (md->prov != NULL)
        return md->name;
#ifndef FIPS_MODE
    return OBJ_nid2sn(EVP_MD_nid(md));
#else
    return NULL;
#endif
}

const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md)
{
    return md->prov;
}

int EVP_MD_block_size(const EVP_MD *md)
{
    if (md == NULL) {
        EVPerr(EVP_F_EVP_MD_BLOCK_SIZE, EVP_R_MESSAGE_DIGEST_IS_NULL);
        return -1;
    }

    if (md->prov != NULL && md->dblock_size != NULL)
        return (int)md->dblock_size();

    return md->block_size;
}

int EVP_MD_type(const EVP_MD *md)
{
    return md->type;
}

int EVP_MD_pkey_type(const EVP_MD *md)
{
    return md->pkey_type;
}

int EVP_MD_size(const EVP_MD *md)
{
    if (!md) {
        EVPerr(EVP_F_EVP_MD_SIZE, EVP_R_MESSAGE_DIGEST_IS_NULL);
        return -1;
    }

    if (md->prov != NULL && md->size != NULL)
        return (int)md->size();

    return md->md_size;
}

unsigned long EVP_MD_flags(const EVP_MD *md)
{
    return md->flags;
}

EVP_MD *EVP_MD_meth_new(int md_type, int pkey_type)
{
    EVP_MD *md = OPENSSL_zalloc(sizeof(*md));

    if (md != NULL) {
        md->type = md_type;
        md->pkey_type = pkey_type;
        md->lock = CRYPTO_THREAD_lock_new();
        if (md->lock == NULL) {
            OPENSSL_free(md);
            return NULL;
        }
        md->refcnt = 1;
    }
    return md;
}

EVP_MD *EVP_MD_meth_dup(const EVP_MD *md)
{
    EVP_MD *to = EVP_MD_meth_new(md->type, md->pkey_type);

    if (to != NULL) {
        CRYPTO_RWLOCK *lock = to->lock;
        memcpy(to, md, sizeof(*to));
        to->lock = lock;
    }
    return to;
}

int EVP_MD_up_ref(EVP_MD *md)
{
    int ref = 0;

    CRYPTO_UP_REF(&md->refcnt, &ref, md->lock);
    return 1;
}

void EVP_MD_meth_free(EVP_MD *md)
{
    if (md != NULL) {
        int i;

        CRYPTO_DOWN_REF(&md->refcnt, &i, md->lock);
        if (i > 0)
            return;
        ossl_provider_free(md->prov);
        OPENSSL_free(md->name);
        CRYPTO_THREAD_lock_free(md->lock);
        OPENSSL_free(md);
    }
}
int EVP_MD_meth_set_input_blocksize(EVP_MD *md, int blocksize)
{
    md->block_size = blocksize;
    return 1;
}
int EVP_MD_meth_set_result_size(EVP_MD *md, int resultsize)
{
    md->md_size = resultsize;
    return 1;
}
int EVP_MD_meth_set_app_datasize(EVP_MD *md, int datasize)
{
    md->ctx_size = datasize;
    return 1;
}
int EVP_MD_meth_set_flags(EVP_MD *md, unsigned long flags)
{
    md->flags = flags;
    return 1;
}
int EVP_MD_meth_set_init(EVP_MD *md, int (*init)(EVP_MD_CTX *ctx))
{
    md->init = init;
    return 1;
}
int EVP_MD_meth_set_update(EVP_MD *md, int (*update)(EVP_MD_CTX *ctx,
                                                     const void *data,
                                                     size_t count))
{
    md->update = update;
    return 1;
}
int EVP_MD_meth_set_final(EVP_MD *md, int (*final)(EVP_MD_CTX *ctx,
                                                   unsigned char *md))
{
    md->final = final;
    return 1;
}
int EVP_MD_meth_set_copy(EVP_MD *md, int (*copy)(EVP_MD_CTX *to,
                                                 const EVP_MD_CTX *from))
{
    md->copy = copy;
    return 1;
}
int EVP_MD_meth_set_cleanup(EVP_MD *md, int (*cleanup)(EVP_MD_CTX *ctx))
{
    md->cleanup = cleanup;
    return 1;
}
int EVP_MD_meth_set_ctrl(EVP_MD *md, int (*ctrl)(EVP_MD_CTX *ctx, int cmd,
                                                 int p1, void *p2))
{
    md->md_ctrl = ctrl;
    return 1;
}

int EVP_MD_meth_get_input_blocksize(const EVP_MD *md)
{
    return md->block_size;
}
int EVP_MD_meth_get_result_size(const EVP_MD *md)
{
    return md->md_size;
}
int EVP_MD_meth_get_app_datasize(const EVP_MD *md)
{
    return md->ctx_size;
}
unsigned long EVP_MD_meth_get_flags(const EVP_MD *md)
{
    return md->flags;
}
int (*EVP_MD_meth_get_init(const EVP_MD *md))(EVP_MD_CTX *ctx)
{
    return md->init;
}
int (*EVP_MD_meth_get_update(const EVP_MD *md))(EVP_MD_CTX *ctx,
                                                const void *data,
                                                size_t count)
{
    return md->update;
}
int (*EVP_MD_meth_get_final(const EVP_MD *md))(EVP_MD_CTX *ctx,
                                               unsigned char *md)
{
    return md->final;
}
int (*EVP_MD_meth_get_copy(const EVP_MD *md))(EVP_MD_CTX *to,
                                              const EVP_MD_CTX *from)
{
    return md->copy;
}
int (*EVP_MD_meth_get_cleanup(const EVP_MD *md))(EVP_MD_CTX *ctx)
{
    return md->cleanup;
}
int (*EVP_MD_meth_get_ctrl(const EVP_MD *md))(EVP_MD_CTX *ctx, int cmd,
                                              int p1, void *p2)
{
    return md->md_ctrl;
}

const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx)
{
    if (ctx == NULL)
        return NULL;
    return ctx->reqdigest;
}

EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx)
{
    return ctx->pctx;
}

#if !defined(FIPS_MODE)
/* TODO(3.0): EVP_DigestSign* not yet supported in FIPS module */
void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx)
{
    /*
     * it's reasonable to set NULL pctx (a.k.a clear the ctx->pctx), so
     * we have to deal with the cleanup job here.
     */
    if (!EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_KEEP_PKEY_CTX))
        EVP_PKEY_CTX_free(ctx->pctx);

    ctx->pctx = pctx;

    if (pctx != NULL) {
        /* make sure pctx is not freed when destroying EVP_MD_CTX */
        EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_KEEP_PKEY_CTX);
    } else {
        EVP_MD_CTX_clear_flags(ctx, EVP_MD_CTX_FLAG_KEEP_PKEY_CTX);
    }
}
#endif /* !defined(FIPS_MODE) */

void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx)
{
    return ctx->md_data;
}

int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
                                             const void *data, size_t count)
{
    return ctx->update;
}

void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
                              int (*update) (EVP_MD_CTX *ctx,
                                             const void *data, size_t count))
{
    ctx->update = update;
}

void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags)
{
    ctx->flags |= flags;
}

void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags)
{
    ctx->flags &= ~flags;
}

int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags)
{
    return (ctx->flags & flags);
}

void EVP_CIPHER_CTX_set_flags(EVP_CIPHER_CTX *ctx, int flags)
{
    ctx->flags |= flags;
}

void EVP_CIPHER_CTX_clear_flags(EVP_CIPHER_CTX *ctx, int flags)
{
    ctx->flags &= ~flags;
}

int EVP_CIPHER_CTX_test_flags(const EVP_CIPHER_CTX *ctx, int flags)
{
    return (ctx->flags & flags);
}

int EVP_str2ctrl(int (*cb)(void *ctx, int cmd, void *buf, size_t buflen),
                 void *ctx, int cmd, const char *value)
{
    size_t len;

    len = strlen(value);
    if (len > INT_MAX)
        return -1;
    return cb(ctx, cmd, (void *)value, len);
}

int EVP_hex2ctrl(int (*cb)(void *ctx, int cmd, void *buf, size_t buflen),
                 void *ctx, int cmd, const char *hex)
{
    unsigned char *bin;
    long binlen;
    int rv = -1;

    bin = OPENSSL_hexstr2buf(hex, &binlen);
    if (bin == NULL)
        return 0;
    if (binlen <= INT_MAX)
        rv = cb(ctx, cmd, bin, binlen);
    OPENSSL_free(bin);
    return rv;
}