path: root/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 "crypto/evp.h"
#include "internal/provider.h"
#include "evp_local.h"

#if !defined(FIPS_MODE)
int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type)
{
    int ret = -1;                /* Assume the worst */
    const EVP_CIPHER *cipher = c->cipher;

    /*
     * For legacy implementations, we detect custom AlgorithmIdentifier
     * parameter handling by checking if the function pointer
     * cipher->set_asn1_parameters is set.  We know that this pointer
     * is NULL for provided implementations.
     *
     * Otherwise, for any implementation, we check the flag
     * EVP_CIPH_FLAG_CUSTOM_ASN1.  If it isn't set, we apply
     * default AI parameter extraction.
     *
     * Otherwise, for provided implementations, we convert |type| to
     * a DER encoded blob and pass to the implementation in OSSL_PARAM
     * form.
     *
     * If none of the above applies, this operation is unsupported.
     */
    if (cipher->set_asn1_parameters != NULL) {
        ret = cipher->set_asn1_parameters(c, type);
    } else if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_CUSTOM_ASN1) == 0) {
        switch (EVP_CIPHER_mode(cipher)) {
        case EVP_CIPH_WRAP_MODE:
            if (EVP_CIPHER_is_a(cipher, SN_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 if (cipher->prov != NULL) {
        OSSL_PARAM params[3], *p = params;
        unsigned char *der = NULL, *derp;

        /*
         * We make two passes, the first to get the appropriate buffer size,
         * and the second to get the actual value.
         */
        *p++ = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_ALG_ID,
                                                 NULL, 0);
        *p = OSSL_PARAM_construct_end();

        if (!EVP_CIPHER_CTX_get_params(c, params))
            goto err;

        /* ... but, we should get a return size too! */
        if (params[0].return_size != 0
            && (der = OPENSSL_malloc(params[0].return_size)) != NULL) {
            params[0].data = der;
            params[0].data_size = params[0].return_size;
            params[0].return_size = 0;
            derp = der;
            if (EVP_CIPHER_CTX_get_params(c, params)
                && d2i_ASN1_TYPE(&type, (const unsigned char **)&derp,
                                 params[0].return_size) != NULL) {
                ret = 1;
            }
            OPENSSL_free(der);
        }
    } else {
        ret = -2;
    }

 err:
    if (ret == -2)
        EVPerr(EVP_F_EVP_CIPHER_PARAM_TO_ASN1, ASN1_R_UNSUPPORTED_CIPHER);
    else if (ret <= 0)
        EVPerr(EVP_F_EVP_CIPHER_PARAM_TO_ASN1, 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 = -1;                /* Assume the worst */
    const EVP_CIPHER *cipher = c->cipher;

    /*
     * For legacy implementations, we detect custom AlgorithmIdentifier
     * parameter handling by checking if there the function pointer
     * cipher->get_asn1_parameters is set.  We know that this pointer
     * is NULL for provided implementations.
     *
     * Otherwise, for any implementation, we check the flag
     * EVP_CIPH_FLAG_CUSTOM_ASN1.  If it isn't set, we apply
     * default AI parameter creation.
     *
     * Otherwise, for provided implementations, we get the AI parameter
     * in DER encoded form from the implementation by requesting the
     * appropriate OSSL_PARAM and converting the result to a ASN1_TYPE.
     *
     * If none of the above applies, this operation is unsupported.
     */
    if (cipher->get_asn1_parameters != NULL) {
        ret = cipher->get_asn1_parameters(c, type);
    } else if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_CUSTOM_ASN1) == 0) {
        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);
        }
    } else if (cipher->prov != NULL) {
        OSSL_PARAM params[3], *p = params;
        unsigned char *der = NULL;
        int derl = -1;

        if ((derl = i2d_ASN1_TYPE(type, &der)) >= 0) {
            *p++ =
                OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_ALG_ID,
                                                  der, (size_t)derl);
            *p = OSSL_PARAM_construct_end();
            if (EVP_CIPHER_CTX_set_params(c, params))
                ret = 1;
            OPENSSL_free(der);
        }
    } else {
        ret = -2;
    }

    if (ret == -2)
        EVPerr(EVP_F_EVP_CIPHER_ASN1_TO_PARAM, EVP_R_UNSUPPORTED_CIPHER);
    else if (ret <= 0)
        EVPerr(EVP_F_EVP_CIPHER_ASN1_TO_PARAM, 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;
    unsigned char *oiv = NULL;

    if (type != NULL) {
        oiv = (unsigned char *)EVP_CIPHER_CTX_original_iv(c);
        j = EVP_CIPHER_CTX_iv_length(c);
        OPENSSL_assert(j <= sizeof(c->iv));
        i = ASN1_TYPE_set_octetstring(type, 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;
    size_t v = cipher->block_size;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

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

    return ok != 0 ? (int)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) {
        /*
         * If the provided implementation has a ccipher function, we use it,
         * and translate its return value like this: 0 => -1, 1 => outlen
         *
         * Otherwise, we call the cupdate function if in != NULL, or cfinal
         * if in == NULL.  Regardless of which, we return what we got.
         */
        int ret = -1;
        size_t outl = 0;
        size_t blocksize = EVP_CIPHER_CTX_block_size(ctx);

        if (ctx->cipher->ccipher != NULL)
            ret =  ctx->cipher->ccipher(ctx->provctx, out, &outl,
                                        inl + (blocksize == 1 ? 0 : blocksize),
                                        in, (size_t)inl)
                ? (int)outl : -1;
        else if (in != NULL)
            ret = ctx->cipher->cupdate(ctx->provctx, out, &outl,
                                       inl + (blocksize == 1 ? 0 : blocksize),
                                       in, (size_t)inl);
        else
            ret = ctx->cipher->cfinal(ctx->provctx, out, &outl,
                                      blocksize == 1 ? 0 : blocksize);

        return ret;
    }

    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);

    /* Provided implementations may have a custom cipher_cipher */
    if (cipher->prov != NULL && cipher->ccipher != NULL)
        v |= EVP_CIPH_FLAG_CUSTOM_CIPHER;

    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;
    size_t v = cipher->iv_len;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

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

    return ok != 0 ? (int)v : EVP_CTRL_RET_UNSUPPORTED;
}

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

    params[0] = OSSL_PARAM_construct_size_t(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 ? (int)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 len;
}

int EVP_CIPHER_CTX_tag_length(const EVP_CIPHER_CTX *ctx)
{
    int ret;
    size_t v = 0;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_TAGLEN, &v);
    ret = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);
    return ret == 1 ? (int)v : 0;
}

const unsigned char *EVP_CIPHER_CTX_original_iv(const EVP_CIPHER_CTX *ctx)
{
    int ok;
    const unsigned char *v = ctx->oiv;
    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->oiv));
    ok = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->provctx, params);

    return ok != 0 ? v : NULL;
}

/*
 * 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;
    unsigned int v = (unsigned int)ctx->num;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

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

    return ok != 0 ? (int)v : EVP_CTRL_RET_UNSUPPORTED;
}

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

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

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

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

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

    return ok != 0 ? (int)v : EVP_CTRL_RET_UNSUPPORTED;
}

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

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

    return ok != 0 ? (int)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;
}

int EVP_CIPHER_is_a(const EVP_CIPHER *cipher, const char *name)
{
#ifndef FIPS_MODE
    if (cipher->prov == NULL) {
        int nid = EVP_CIPHER_nid(cipher);

        return nid == OBJ_sn2nid(name) || nid == OBJ_ln2nid(name);
    }
#endif
    return evp_is_a(cipher->prov, cipher->name_id, name);
}

const char *EVP_CIPHER_name(const EVP_CIPHER *cipher)
{
    if (cipher->prov != NULL)
        return evp_first_name(cipher->prov, cipher->name_id);
#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;
    unsigned int v = EVP_CIPHER_flags(cipher) & EVP_CIPH_MODE;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

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

    return ok != 0 ? (int)v : 0;
}

const char *EVP_MD_name(const EVP_MD *md)
{
    if (md->prov != NULL)
        return evp_first_name(md->prov, md->name_id);
#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)
{
    int ok;
    size_t v = md->block_size;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    if (md == NULL) {
        EVPerr(EVP_F_EVP_MD_BLOCK_SIZE, EVP_R_MESSAGE_DIGEST_IS_NULL);
        return -1;
    }

    params[0] = OSSL_PARAM_construct_size_t(OSSL_DIGEST_PARAM_BLOCK_SIZE, &v);
    ok = evp_do_md_getparams(md, params);

    return ok != 0 ? (int)v : -1;
}

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)
{
    int ok;
    size_t v = md->md_size;
    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    if (md == NULL) {
        EVPerr(EVP_F_EVP_MD_SIZE, EVP_R_MESSAGE_DIGEST_IS_NULL);
        return -1;
    }

    params[0] = OSSL_PARAM_construct_size_t(OSSL_DIGEST_PARAM_SIZE, &v);
    ok = evp_do_md_getparams(md, params);

    return ok != 0 ? (int)v : -1;
}

unsigned long EVP_MD_flags(const EVP_MD *md)
{
    int ok;
    unsigned long v = md->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_md_getparams(md, params);

    return ok != 0 ? v : 0;
}

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

    if (md != NULL) {
        md->type = md_type;
        md->pkey_type = pkey_type;
    }
    return md;
}

EVP_MD *EVP_MD_meth_dup(const EVP_MD *md)
{
    EVP_MD *to = NULL;

    /*
     * Non-legacy EVP_MDs can't be duplicated like this.
     * Use EVP_MD_up_ref() instead.
     */
    if (md->prov != NULL)
        return NULL;

    if ((to = EVP_MD_meth_new(md->type, md->pkey_type)) != NULL) {
        CRYPTO_RWLOCK *lock = to->lock;

        memcpy(to, md, sizeof(*to));
        to->lock = lock;
    }
    return to;
}

void EVP_MD_meth_free(EVP_MD *md)
{
    EVP_MD_free(md);
}
int EVP_MD_meth_set_input_blocksize(EVP_MD *md, int blocksize)
{
    if (md->block_size != 0)
        return 0;

    md->block_size = blocksize;
    return 1;
}
int EVP_MD_meth_set_result_size(EVP_MD *md, int resultsize)
{
    if (md->md_size != 0)
        return 0;

    md->md_size = resultsize;
    return 1;
}
int EVP_MD_meth_set_app_datasize(EVP_MD *md, int datasize)
{
    if (md->ctx_size != 0)
        return 0;

    md->ctx_size = datasize;
    return 1;
}
int EVP_MD_meth_set_flags(EVP_MD *md, unsigned long flags)
{
    if (md->flags != 0)
        return 0;

    md->flags = flags;
    return 1;
}
int EVP_MD_meth_set_init(EVP_MD *md, int (*init)(EVP_MD_CTX *ctx))
{
    if (md->init != NULL)
        return 0;

    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))
{
    if (md->update != NULL)
        return 0;

    md->update = update;
    return 1;
}
int EVP_MD_meth_set_final(EVP_MD *md, int (*final)(EVP_MD_CTX *ctx,
                                                   unsigned char *md))
{
    if (md->final != NULL)
        return 0;

    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))
{
    if (md->copy != NULL)
        return 0;

    md->copy = copy;
    return 1;
}
int EVP_MD_meth_set_cleanup(EVP_MD *md, int (*cleanup)(EVP_MD_CTX *ctx))
{
    if (md->cleanup != NULL)
        return 0;

    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))
{
    if (md->md_ctrl != NULL)
        return 0;

    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;
}