/*

 * Copyright 2020-2021 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

 */

/*

 * ECDSA low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <string.h> /* memcpy */

#include <openssl/crypto.h>

#include <openssl/core_dispatch.h>

#include <openssl/core_names.h>

#include <openssl/dsa.h>

#include <openssl/params.h>

#include <openssl/evp.h>

#include <openssl/err.h>

#include <openssl/proverr.h>

#include "internal/nelem.h"

#include "internal/sizes.h"

#include "internal/cryptlib.h"

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/provider_ctx.h"

#include "prov/securitycheck.h"

#include "crypto/ec.h"

#include "prov/der_ec.h"

static OSSL_FUNC_signature_newctx_fn ecdsa_newctx;

static OSSL_FUNC_signature_sign_init_fn ecdsa_sign_init;

static OSSL_FUNC_signature_verify_init_fn ecdsa_verify_init;

static OSSL_FUNC_signature_sign_fn ecdsa_sign;

static OSSL_FUNC_signature_verify_fn ecdsa_verify;

static OSSL_FUNC_signature_digest_sign_init_fn ecdsa_digest_sign_init;

static OSSL_FUNC_signature_digest_sign_update_fn ecdsa_digest_signverify_update;

static OSSL_FUNC_signature_digest_sign_final_fn ecdsa_digest_sign_final;

static OSSL_FUNC_signature_digest_verify_init_fn ecdsa_digest_verify_init;

static OSSL_FUNC_signature_digest_verify_update_fn ecdsa_digest_signverify_update;

static OSSL_FUNC_signature_digest_verify_final_fn ecdsa_digest_verify_final;

static OSSL_FUNC_signature_freectx_fn ecdsa_freectx;

static OSSL_FUNC_signature_dupctx_fn ecdsa_dupctx;

static OSSL_FUNC_signature_get_ctx_params_fn ecdsa_get_ctx_params;

static OSSL_FUNC_signature_gettable_ctx_params_fn ecdsa_gettable_ctx_params;

static OSSL_FUNC_signature_set_ctx_params_fn ecdsa_set_ctx_params;

static OSSL_FUNC_signature_settable_ctx_params_fn ecdsa_settable_ctx_params;

static OSSL_FUNC_signature_get_ctx_md_params_fn ecdsa_get_ctx_md_params;

static OSSL_FUNC_signature_gettable_ctx_md_params_fn ecdsa_gettable_ctx_md_params;

static OSSL_FUNC_signature_set_ctx_md_params_fn ecdsa_set_ctx_md_params;

static OSSL_FUNC_signature_settable_ctx_md_params_fn ecdsa_settable_ctx_md_params;

/*

 * What's passed as an actual key is defined by the KEYMGMT interface.

 * We happen to know that our KEYMGMT simply passes DSA structures, so

 * we use that here too.

 */

typedef struct {

    OSSL_LIB_CTX *libctx;

    char *propq;

    EC_KEY *ec;

    char mdname[OSSL_MAX_NAME_SIZE];

    /*

     * Flag to determine if the hash function can be changed (1) or not (0)

     * Because it's dangerous to change during a DigestSign or DigestVerify

     * operation, this flag is cleared by their Init function, and set again

     * by their Final function.

     */

    unsigned int flag_allow_md : 1;

    /* The Algorithm Identifier of the combined signature algorithm */

    unsigned char aid_buf[OSSL_MAX_ALGORITHM_ID_SIZE];

    unsigned char *aid;

    size_t aid_len;

    size_t mdsize;

    int operation;

    EVP_MD *md;

    EVP_MD_CTX *mdctx;

    /*

     * Internally used to cache the results of calling the EC group

     * sign_setup() methods which are then passed to the sign operation.

     * This is used by CAVS failure tests to terminate a loop if the signature

     * is not valid.

     * This could of also been done with a simple flag.

     */

    BIGNUM *kinv;

    BIGNUM *r;

#if !defined(OPENSSL_NO_ACVP_TESTS)

    /*

     * This indicates that KAT (CAVS) test is running. Externally an app will

     * override the random callback such that the generated private key and k

     * are known.

     * Normal operation will loop to choose a new k if the signature is not

     * valid - but for this mode of operation it forces a failure instead.

     */

    unsigned int kattest;

#endif

} PROV_ECDSA_CTX;

static void *ecdsa_newctx(void *provctx, const char *propq)

{

    PROV_ECDSA_CTX *ctx;

    if (!ossl_prov_is_running())

        return NULL;

    ctx = OPENSSL_zalloc(sizeof(PROV_ECDSA_CTX));

    if (ctx == NULL)

        return NULL;

    ctx->flag_allow_md = 1;

    ctx->libctx = PROV_LIBCTX_OF(provctx);

    if (propq != NULL && (ctx->propq = OPENSSL_strdup(propq)) == NULL) {

        OPENSSL_free(ctx);

        ctx = NULL;

        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);

    }

    return ctx;

}

static int ecdsa_signverify_init(void *vctx, void *ec,

    const OSSL_PARAM params[], int operation)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (!ossl_prov_is_running()

        || ctx == NULL)

        return 0;

    if (ec == NULL && ctx->ec == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);

        return 0;

    }

    if (ec != NULL) {

        if (!ossl_ec_check_key(ctx->libctx, ec, operation == EVP_PKEY_OP_SIGN))

            return 0;

        if (!EC_KEY_up_ref(ec))

            return 0;

        EC_KEY_free(ctx->ec);

        ctx->ec = ec;

    }

    ctx->operation = operation;

    if (!ecdsa_set_ctx_params(ctx, params))

        return 0;

    return 1;

}

static int ecdsa_sign_init(void *vctx, void *ec, const OSSL_PARAM params[])

{

    return ecdsa_signverify_init(vctx, ec, params, EVP_PKEY_OP_SIGN);

}

static int ecdsa_verify_init(void *vctx, void *ec, const OSSL_PARAM params[])

{

    return ecdsa_signverify_init(vctx, ec, params, EVP_PKEY_OP_VERIFY);

}

static int ecdsa_sign(void *vctx, unsigned char *sig, size_t *siglen,

    size_t sigsize, const unsigned char *tbs, size_t tbslen)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    int ret;

    unsigned int sltmp;

    size_t ecsize = ECDSA_size(ctx->ec);

    if (!ossl_prov_is_running())

        return 0;

    if (sig == NULL) {

        *siglen = ecsize;

        return 1;

    }

#if !defined(OPENSSL_NO_ACVP_TESTS)

    if (ctx->kattest && !ECDSA_sign_setup(ctx->ec, NULL, &ctx->kinv, &ctx->r))

        return 0;

#endif

    if (sigsize < (size_t)ecsize)

        return 0;

    if (ctx->mdsize != 0 && tbslen != ctx->mdsize)

        return 0;

    ret = ECDSA_sign_ex(0, tbs, tbslen, sig, &sltmp, ctx->kinv, ctx->r, ctx->ec);

    if (ret <= 0)

        return 0;

    *siglen = sltmp;

    return 1;

}

static int ecdsa_verify(void *vctx, const unsigned char *sig, size_t siglen,

    const unsigned char *tbs, size_t tbslen)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (!ossl_prov_is_running() || (ctx->mdsize != 0 && tbslen != ctx->mdsize))

        return 0;

    return ECDSA_verify(0, tbs, tbslen, sig, siglen, ctx->ec);

}

static int ecdsa_setup_md(PROV_ECDSA_CTX *ctx, const char *mdname,

    const char *mdprops)

{

    EVP_MD *md = NULL;

    size_t mdname_len;

    int md_nid, sha1_allowed;

    WPACKET pkt;

    if (mdname == NULL)

        return 1;

    mdname_len = strlen(mdname);

    if (mdname_len >= sizeof(ctx->mdname)) {

        ERR_raise_data(ERR_LIB_PROV, PROV_R_INVALID_DIGEST,

            "%s exceeds name buffer length", mdname);

        return 0;

    }

    if (mdprops == NULL)

        mdprops = ctx->propq;

    md = EVP_MD_fetch(ctx->libctx, mdname, mdprops);

    if (md == NULL) {

        ERR_raise_data(ERR_LIB_PROV, PROV_R_INVALID_DIGEST,

            "%s could not be fetched", mdname);

        return 0;

    }

    sha1_allowed = (ctx->operation != EVP_PKEY_OP_SIGN);

    md_nid = ossl_digest_get_approved_nid_with_sha1(ctx->libctx, md,

        sha1_allowed);

    if (md_nid < 0) {

        ERR_raise_data(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED,

            "digest=%s", mdname);

        EVP_MD_free(md);

        return 0;

    }

    if (!ctx->flag_allow_md) {

        if (ctx->mdname[0] != '\0' && !EVP_MD_is_a(md, ctx->mdname)) {

            ERR_raise_data(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED,

                "digest %s != %s", mdname, ctx->mdname);

            EVP_MD_free(md);

            return 0;

        }

        EVP_MD_free(md);

        return 1;

    }

    EVP_MD_CTX_free(ctx->mdctx);

    EVP_MD_free(ctx->md);

    ctx->aid_len = 0;

    if (WPACKET_init_der(&pkt, ctx->aid_buf, sizeof(ctx->aid_buf))

        && ossl_DER_w_algorithmIdentifier_ECDSA_with_MD(&pkt, -1, ctx->ec,

            md_nid)

        && WPACKET_finish(&pkt)) {

        WPACKET_get_total_written(&pkt, &ctx->aid_len);

        ctx->aid = WPACKET_get_curr(&pkt);

    }

    WPACKET_cleanup(&pkt);

    ctx->mdctx = NULL;

    ctx->md = md;

    ctx->mdsize = EVP_MD_get_size(ctx->md);

    OPENSSL_strlcpy(ctx->mdname, mdname, sizeof(ctx->mdname));

    return 1;

}

static int ecdsa_digest_signverify_init(void *vctx, const char *mdname,

    void *ec, const OSSL_PARAM params[],

    int operation)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (!ossl_prov_is_running())

        return 0;

    if (!ecdsa_signverify_init(vctx, ec, params, operation)

        || !ecdsa_setup_md(ctx, mdname, NULL))

        return 0;

    ctx->flag_allow_md = 0;

    if (ctx->mdctx == NULL) {

        ctx->mdctx = EVP_MD_CTX_new();

        if (ctx->mdctx == NULL)

            goto error;

    }

    if (!EVP_DigestInit_ex2(ctx->mdctx, ctx->md, params))

        goto error;

    return 1;

error:

    EVP_MD_CTX_free(ctx->mdctx);

    ctx->mdctx = NULL;

    return 0;

}

static int ecdsa_digest_sign_init(void *vctx, const char *mdname, void *ec,

    const OSSL_PARAM params[])

{

    return ecdsa_digest_signverify_init(vctx, mdname, ec, params,

        EVP_PKEY_OP_SIGN);

}

static int ecdsa_digest_verify_init(void *vctx, const char *mdname, void *ec,

    const OSSL_PARAM params[])

{

    return ecdsa_digest_signverify_init(vctx, mdname, ec, params,

        EVP_PKEY_OP_VERIFY);

}

int ecdsa_digest_signverify_update(void *vctx, const unsigned char *data,

    size_t datalen)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx == NULL || ctx->mdctx == NULL)

        return 0;

    return EVP_DigestUpdate(ctx->mdctx, data, datalen);

}

int ecdsa_digest_sign_final(void *vctx, unsigned char *sig, size_t *siglen,

    size_t sigsize)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    unsigned char digest[EVP_MAX_MD_SIZE];

    unsigned int dlen = 0;

    if (!ossl_prov_is_running() || ctx == NULL || ctx->mdctx == NULL)

        return 0;

    /*

     * If sig is NULL then we're just finding out the sig size. Other fields

     * are ignored. Defer to ecdsa_sign.

     */

    if (sig != NULL

        && !EVP_DigestFinal_ex(ctx->mdctx, digest, &dlen))

        return 0;

    ctx->flag_allow_md = 1;

    return ecdsa_sign(vctx, sig, siglen, sigsize, digest, (size_t)dlen);

}

int ecdsa_digest_verify_final(void *vctx, const unsigned char *sig,

    size_t siglen)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    unsigned char digest[EVP_MAX_MD_SIZE];

    unsigned int dlen = 0;

    if (!ossl_prov_is_running() || ctx == NULL || ctx->mdctx == NULL)

        return 0;

    if (!EVP_DigestFinal_ex(ctx->mdctx, digest, &dlen))

        return 0;

    ctx->flag_allow_md = 1;

    return ecdsa_verify(ctx, sig, siglen, digest, (size_t)dlen);

}

static void ecdsa_freectx(void *vctx)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    OPENSSL_free(ctx->propq);

    EVP_MD_CTX_free(ctx->mdctx);

    EVP_MD_free(ctx->md);

    ctx->propq = NULL;

    ctx->mdctx = NULL;

    ctx->md = NULL;

    ctx->mdsize = 0;

    EC_KEY_free(ctx->ec);

    BN_clear_free(ctx->kinv);

    BN_clear_free(ctx->r);

    OPENSSL_free(ctx);

}

static void *ecdsa_dupctx(void *vctx)

{

    PROV_ECDSA_CTX *srcctx = (PROV_ECDSA_CTX *)vctx;

    PROV_ECDSA_CTX *dstctx;

    if (!ossl_prov_is_running())

        return NULL;

    dstctx = OPENSSL_zalloc(sizeof(*srcctx));

    if (dstctx == NULL)

        return NULL;

    *dstctx = *srcctx;

    dstctx->ec = NULL;

    dstctx->md = NULL;

    dstctx->mdctx = NULL;

    dstctx->propq = NULL;

    if (srcctx->ec != NULL && !EC_KEY_up_ref(srcctx->ec))

        goto err;

    /* Test KATS should not need to be supported */

    if (srcctx->kinv != NULL || srcctx->r != NULL)

        goto err;

    dstctx->ec = srcctx->ec;

    if (srcctx->md != NULL && !EVP_MD_up_ref(srcctx->md))

        goto err;

    dstctx->md = srcctx->md;

    if (srcctx->mdctx != NULL) {

        dstctx->mdctx = EVP_MD_CTX_new();

        if (dstctx->mdctx == NULL

            || !EVP_MD_CTX_copy_ex(dstctx->mdctx, srcctx->mdctx))

            goto err;

    }

    if (srcctx->propq != NULL) {

        dstctx->propq = OPENSSL_strdup(srcctx->propq);

        if (dstctx->propq == NULL)

            goto err;

    }

    return dstctx;

err:

    ecdsa_freectx(dstctx);

    return NULL;

}

static int ecdsa_get_ctx_params(void *vctx, OSSL_PARAM *params)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    OSSL_PARAM *p;

    if (ctx == NULL)

        return 0;

    p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_ALGORITHM_ID);

    if (p != NULL && !OSSL_PARAM_set_octet_string(p, ctx->aid, ctx->aid_len))

        return 0;

    p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST_SIZE);

    if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->mdsize))

        return 0;

    p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST);

    if (p != NULL && !OSSL_PARAM_set_utf8_string(p, ctx->md == NULL ? ctx->mdname : EVP_MD_get0_name(ctx->md)))

        return 0;

    return 1;

}

static const OSSL_PARAM known_gettable_ctx_params[] = {

    OSSL_PARAM_octet_string(OSSL_SIGNATURE_PARAM_ALGORITHM_ID, NULL, 0),

    OSSL_PARAM_size_t(OSSL_SIGNATURE_PARAM_DIGEST_SIZE, NULL),

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),

    OSSL_PARAM_END

};

static const OSSL_PARAM *ecdsa_gettable_ctx_params(ossl_unused void *vctx,

    ossl_unused void *provctx)

{

    return known_gettable_ctx_params;

}

static int ecdsa_set_ctx_params(void *vctx, const OSSL_PARAM params[])

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    const OSSL_PARAM *p;

    size_t mdsize = 0;

    if (ctx == NULL)

        return 0;

    if (params == NULL)

        return 1;

#if !defined(OPENSSL_NO_ACVP_TESTS)

    p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_KAT);

    if (p != NULL && !OSSL_PARAM_get_uint(p, &ctx->kattest))

        return 0;

#endif

    p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST);

    if (p != NULL) {

        char mdname[OSSL_MAX_NAME_SIZE] = "", *pmdname = mdname;

        char mdprops[OSSL_MAX_PROPQUERY_SIZE] = "", *pmdprops = mdprops;

        const OSSL_PARAM *propsp = OSSL_PARAM_locate_const(params,

            OSSL_SIGNATURE_PARAM_PROPERTIES);

        if (!OSSL_PARAM_get_utf8_string(p, &pmdname, sizeof(mdname)))

            return 0;

        if (propsp != NULL

            && !OSSL_PARAM_get_utf8_string(propsp, &pmdprops, sizeof(mdprops)))

            return 0;

        if (!ecdsa_setup_md(ctx, mdname, mdprops))

            return 0;

    }

    p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST_SIZE);

    if (p != NULL) {

        if (!OSSL_PARAM_get_size_t(p, &mdsize)

            || (!ctx->flag_allow_md && mdsize != ctx->mdsize))

            return 0;

        ctx->mdsize = mdsize;

    }

    return 1;

}

static const OSSL_PARAM settable_ctx_params[] = {

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),

    OSSL_PARAM_size_t(OSSL_SIGNATURE_PARAM_DIGEST_SIZE, NULL),

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_PROPERTIES, NULL, 0),

    OSSL_PARAM_uint(OSSL_SIGNATURE_PARAM_KAT, NULL),

    OSSL_PARAM_END

};

static const OSSL_PARAM settable_ctx_params_no_digest[] = {

    OSSL_PARAM_uint(OSSL_SIGNATURE_PARAM_KAT, NULL),

    OSSL_PARAM_END

};

static const OSSL_PARAM *ecdsa_settable_ctx_params(void *vctx,

    ossl_unused void *provctx)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx != NULL && !ctx->flag_allow_md)

        return settable_ctx_params_no_digest;

    return settable_ctx_params;

}

static int ecdsa_get_ctx_md_params(void *vctx, OSSL_PARAM *params)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx->mdctx == NULL)

        return 0;

    return EVP_MD_CTX_get_params(ctx->mdctx, params);

}

static const OSSL_PARAM *ecdsa_gettable_ctx_md_params(void *vctx)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx->md == NULL)

        return 0;

    return EVP_MD_gettable_ctx_params(ctx->md);

}

static int ecdsa_set_ctx_md_params(void *vctx, const OSSL_PARAM params[])

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx->mdctx == NULL)

        return 0;

    return EVP_MD_CTX_set_params(ctx->mdctx, params);

}

static const OSSL_PARAM *ecdsa_settable_ctx_md_params(void *vctx)

{

    PROV_ECDSA_CTX *ctx = (PROV_ECDSA_CTX *)vctx;

    if (ctx->md == NULL)

        return 0;

    return EVP_MD_settable_ctx_params(ctx->md);

}

const OSSL_DISPATCH ossl_ecdsa_signature_functions[] = {

    { OSSL_FUNC_SIGNATURE_NEWCTX, (void (*)(void))ecdsa_newctx },

    { OSSL_FUNC_SIGNATURE_SIGN_INIT, (void (*)(void))ecdsa_sign_init },

    { OSSL_FUNC_SIGNATURE_SIGN, (void (*)(void))ecdsa_sign },

    { OSSL_FUNC_SIGNATURE_VERIFY_INIT, (void (*)(void))ecdsa_verify_init },

    { OSSL_FUNC_SIGNATURE_VERIFY, (void (*)(void))ecdsa_verify },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT,

        (void (*)(void))ecdsa_digest_sign_init },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE,

        (void (*)(void))ecdsa_digest_signverify_update },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL,

        (void (*)(void))ecdsa_digest_sign_final },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT,

        (void (*)(void))ecdsa_digest_verify_init },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE,

        (void (*)(void))ecdsa_digest_signverify_update },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL,

        (void (*)(void))ecdsa_digest_verify_final },

    { OSSL_FUNC_SIGNATURE_FREECTX, (void (*)(void))ecdsa_freectx },

    { OSSL_FUNC_SIGNATURE_DUPCTX, (void (*)(void))ecdsa_dupctx },

    { OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS, (void (*)(void))ecdsa_get_ctx_params },

    { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS,

        (void (*)(void))ecdsa_gettable_ctx_params },

    { OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS, (void (*)(void))ecdsa_set_ctx_params },

    { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS,

        (void (*)(void))ecdsa_settable_ctx_params },

    { OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS,

        (void (*)(void))ecdsa_get_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS,

        (void (*)(void))ecdsa_gettable_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS,

        (void (*)(void))ecdsa_set_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS,

        (void (*)(void))ecdsa_settable_ctx_md_params },

    { 0, NULL }

};