openssl/crypto/evp/pmeth_lib.c

/*
 * Copyright 2006-2017 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (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 <stdlib.h>
#include "internal/cryptlib.h"
#include <openssl/engine.h>
#include <openssl/evp.h>
#include <openssl/x509v3.h>
#include "internal/asn1_int.h"
#include "internal/evp_int.h"
#include "internal/numbers.h"

typedef int sk_cmp_fn_type(const char *const *a, const char *const *b);

static STACK_OF(EVP_PKEY_METHOD) *app_pkey_methods = NULL;

static const EVP_PKEY_METHOD *standard_methods[] = {
#ifndef OPENSSL_NO_RSA
    &rsa_pkey_meth,
#endif
#ifndef OPENSSL_NO_DH
    &dh_pkey_meth,
#endif
#ifndef OPENSSL_NO_DSA
    &dsa_pkey_meth,
#endif
#ifndef OPENSSL_NO_EC
    &ec_pkey_meth,
#endif
    &hmac_pkey_meth,
#ifndef OPENSSL_NO_CMAC
    &cmac_pkey_meth,
#endif
#ifndef OPENSSL_NO_RSA
    &rsa_pss_pkey_meth,
#endif
#ifndef OPENSSL_NO_DH
    &dhx_pkey_meth,
#endif
    &tls1_prf_pkey_meth,
#ifndef OPENSSL_NO_EC
    &ecx25519_pkey_meth,
#endif
    &hkdf_pkey_meth,
#ifndef OPENSSL_NO_POLY1305
    &poly1305_pkey_meth,
#endif
#ifndef OPENSSL_NO_SIPHASH
    &siphash_pkey_meth,
#endif
};

DECLARE_OBJ_BSEARCH_CMP_FN(const EVP_PKEY_METHOD *, const EVP_PKEY_METHOD *,
                           pmeth);

static int pmeth_cmp(const EVP_PKEY_METHOD *const *a,
                     const EVP_PKEY_METHOD *const *b)
{
    return ((*a)->pkey_id - (*b)->pkey_id);
}

IMPLEMENT_OBJ_BSEARCH_CMP_FN(const EVP_PKEY_METHOD *, const EVP_PKEY_METHOD *,
                             pmeth);

const EVP_PKEY_METHOD *EVP_PKEY_meth_find(int type)
{
    EVP_PKEY_METHOD tmp;
    const EVP_PKEY_METHOD *t = &tmp, **ret;
    tmp.pkey_id = type;
    if (app_pkey_methods) {
        int idx;
        idx = sk_EVP_PKEY_METHOD_find(app_pkey_methods, &tmp);
        if (idx >= 0)
            return sk_EVP_PKEY_METHOD_value(app_pkey_methods, idx);
    }
    ret = OBJ_bsearch_pmeth(&t, standard_methods,
                            sizeof(standard_methods) /
                            sizeof(EVP_PKEY_METHOD *));
    if (!ret || !*ret)
        return NULL;
    return *ret;
}

static EVP_PKEY_CTX *int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
{
    EVP_PKEY_CTX *ret;
    const EVP_PKEY_METHOD *pmeth;
    if (id == -1) {
        if (!pkey || !pkey->ameth)
            return NULL;
        id = pkey->ameth->pkey_id;
    }
#ifndef OPENSSL_NO_ENGINE
    if (pkey && pkey->engine)
        e = pkey->engine;
    /* Try to find an ENGINE which implements this method */
    if (e) {
        if (!ENGINE_init(e)) {
            EVPerr(EVP_F_INT_CTX_NEW, ERR_R_ENGINE_LIB);
            return NULL;
        }
    } else
        e = ENGINE_get_pkey_meth_engine(id);

    /*
     * If an ENGINE handled this method look it up. Otherwise use internal
     * tables.
     */

    if (e)
        pmeth = ENGINE_get_pkey_meth(e, id);
    else
#endif
        pmeth = EVP_PKEY_meth_find(id);

    if (pmeth == NULL) {
        EVPerr(EVP_F_INT_CTX_NEW, EVP_R_UNSUPPORTED_ALGORITHM);
        return NULL;
    }

    ret = OPENSSL_zalloc(sizeof(*ret));
    if (ret == NULL) {
#ifndef OPENSSL_NO_ENGINE
        ENGINE_finish(e);
#endif
        EVPerr(EVP_F_INT_CTX_NEW, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    ret->engine = e;
    ret->pmeth = pmeth;
    ret->operation = EVP_PKEY_OP_UNDEFINED;
    ret->pkey = pkey;
    if (pkey)
        EVP_PKEY_up_ref(pkey);

    if (pmeth->init) {
        if (pmeth->init(ret) <= 0) {
            ret->pmeth = NULL;
            EVP_PKEY_CTX_free(ret);
            return NULL;
        }
    }

    return ret;
}

EVP_PKEY_METHOD *EVP_PKEY_meth_new(int id, int flags)
{
    EVP_PKEY_METHOD *pmeth;

    pmeth = OPENSSL_zalloc(sizeof(*pmeth));
    if (pmeth == NULL)
        return NULL;

    pmeth->pkey_id = id;
    pmeth->flags = flags | EVP_PKEY_FLAG_DYNAMIC;
    return pmeth;
}

void EVP_PKEY_meth_get0_info(int *ppkey_id, int *pflags,
                             const EVP_PKEY_METHOD *meth)
{
    if (ppkey_id)
        *ppkey_id = meth->pkey_id;
    if (pflags)
        *pflags = meth->flags;
}

void EVP_PKEY_meth_copy(EVP_PKEY_METHOD *dst, const EVP_PKEY_METHOD *src)
{

    dst->init = src->init;
    dst->copy = src->copy;
    dst->cleanup = src->cleanup;

    dst->paramgen_init = src->paramgen_init;
    dst->paramgen = src->paramgen;

    dst->keygen_init = src->keygen_init;
    dst->keygen = src->keygen;

    dst->sign_init = src->sign_init;
    dst->sign = src->sign;

    dst->verify_init = src->verify_init;
    dst->verify = src->verify;

    dst->verify_recover_init = src->verify_recover_init;
    dst->verify_recover = src->verify_recover;

    dst->signctx_init = src->signctx_init;
    dst->signctx = src->signctx;

    dst->verifyctx_init = src->verifyctx_init;
    dst->verifyctx = src->verifyctx;

    dst->encrypt_init = src->encrypt_init;
    dst->encrypt = src->encrypt;

    dst->decrypt_init = src->decrypt_init;
    dst->decrypt = src->decrypt;

    dst->derive_init = src->derive_init;
    dst->derive = src->derive;

    dst->ctrl = src->ctrl;
    dst->ctrl_str = src->ctrl_str;
}

void EVP_PKEY_meth_free(EVP_PKEY_METHOD *pmeth)
{
    if (pmeth && (pmeth->flags & EVP_PKEY_FLAG_DYNAMIC))
        OPENSSL_free(pmeth);
}

EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e)
{
    return int_ctx_new(pkey, e, -1);
}

EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e)
{
    return int_ctx_new(NULL, e, id);
}

EVP_PKEY_CTX *EVP_PKEY_CTX_dup(EVP_PKEY_CTX *pctx)
{
    EVP_PKEY_CTX *rctx;
    if (!pctx->pmeth || !pctx->pmeth->copy)
        return NULL;
#ifndef OPENSSL_NO_ENGINE
    /* Make sure it's safe to copy a pkey context using an ENGINE */
    if (pctx->engine && !ENGINE_init(pctx->engine)) {
        EVPerr(EVP_F_EVP_PKEY_CTX_DUP, ERR_R_ENGINE_LIB);
        return 0;
    }
#endif
    rctx = OPENSSL_malloc(sizeof(*rctx));
    if (rctx == NULL)
        return NULL;

    rctx->pmeth = pctx->pmeth;
#ifndef OPENSSL_NO_ENGINE
    rctx->engine = pctx->engine;
#endif

    if (pctx->pkey)
        EVP_PKEY_up_ref(pctx->pkey);

    rctx->pkey = pctx->pkey;

    if (pctx->peerkey)
        EVP_PKEY_up_ref(pctx->peerkey);

    rctx->peerkey = pctx->peerkey;

    rctx->data = NULL;
    rctx->app_data = NULL;
    rctx->operation = pctx->operation;

    if (pctx->pmeth->copy(rctx, pctx) > 0)
        return rctx;

    rctx->pmeth = NULL;
    EVP_PKEY_CTX_free(rctx);
    return NULL;

}

int EVP_PKEY_meth_add0(const EVP_PKEY_METHOD *pmeth)
{
    if (app_pkey_methods == NULL) {
        app_pkey_methods = sk_EVP_PKEY_METHOD_new(pmeth_cmp);
        if (app_pkey_methods == NULL)
            return 0;
    }
    if (!sk_EVP_PKEY_METHOD_push(app_pkey_methods, pmeth))
        return 0;
    sk_EVP_PKEY_METHOD_sort(app_pkey_methods);
    return 1;
}

void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx)
{
    if (ctx == NULL)
        return;
    if (ctx->pmeth && ctx->pmeth->cleanup)
        ctx->pmeth->cleanup(ctx);
    EVP_PKEY_free(ctx->pkey);
    EVP_PKEY_free(ctx->peerkey);
#ifndef OPENSSL_NO_ENGINE
    ENGINE_finish(ctx->engine);
#endif
    OPENSSL_free(ctx);
}

int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
                      int cmd, int p1, void *p2)
{
    int ret;
    if (!ctx || !ctx->pmeth || !ctx->pmeth->ctrl) {
        EVPerr(EVP_F_EVP_PKEY_CTX_CTRL, EVP_R_COMMAND_NOT_SUPPORTED);
        return -2;
    }
    if ((keytype != -1) && (ctx->pmeth->pkey_id != keytype))
        return -1;

    if (ctx->operation == EVP_PKEY_OP_UNDEFINED) {
        EVPerr(EVP_F_EVP_PKEY_CTX_CTRL, EVP_R_NO_OPERATION_SET);
        return -1;
    }

    if ((optype != -1) && !(ctx->operation & optype)) {
        EVPerr(EVP_F_EVP_PKEY_CTX_CTRL, EVP_R_INVALID_OPERATION);
        return -1;
    }

    ret = ctx->pmeth->ctrl(ctx, cmd, p1, p2);

    if (ret == -2)
        EVPerr(EVP_F_EVP_PKEY_CTX_CTRL, EVP_R_COMMAND_NOT_SUPPORTED);

    return ret;

}

int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx,
                          const char *name, const char *value)
{
    if (!ctx || !ctx->pmeth || !ctx->pmeth->ctrl_str) {
        EVPerr(EVP_F_EVP_PKEY_CTX_CTRL_STR, EVP_R_COMMAND_NOT_SUPPORTED);
        return -2;
    }
    if (strcmp(name, "digest") == 0)
        return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_TYPE_SIG, EVP_PKEY_CTRL_MD,
                               value);
    return ctx->pmeth->ctrl_str(ctx, name, value);
}

/* Utility functions to send a string of hex string to a ctrl */

int EVP_PKEY_CTX_str2ctrl(EVP_PKEY_CTX *ctx, int cmd, const char *str)
{
    size_t len;

    len = strlen(str);
    if (len > INT_MAX)
        return -1;
    return ctx->pmeth->ctrl(ctx, cmd, len, (void *)str);
}

int EVP_PKEY_CTX_hex2ctrl(EVP_PKEY_CTX *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 = ctx->pmeth->ctrl(ctx, cmd, binlen, bin);
    OPENSSL_free(bin);
    return rv;
}

/* Pass a message digest to a ctrl */
int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md)
{
    const EVP_MD *m;

    if (md == NULL || (m = EVP_get_digestbyname(md)) == NULL) {
        EVPerr(EVP_F_EVP_PKEY_CTX_MD, EVP_R_INVALID_DIGEST);
        return 0;
    }
    return EVP_PKEY_CTX_ctrl(ctx, -1, optype, cmd, 0, (void *)m);
}

int EVP_PKEY_CTX_get_operation(EVP_PKEY_CTX *ctx)
{
    return ctx->operation;
}

void EVP_PKEY_CTX_set0_keygen_info(EVP_PKEY_CTX *ctx, int *dat, int datlen)
{
    ctx->keygen_info = dat;
    ctx->keygen_info_count = datlen;
}

void EVP_PKEY_CTX_set_data(EVP_PKEY_CTX *ctx, void *data)
{
    ctx->data = data;
}

void *EVP_PKEY_CTX_get_data(EVP_PKEY_CTX *ctx)
{
    return ctx->data;
}

EVP_PKEY *EVP_PKEY_CTX_get0_pkey(EVP_PKEY_CTX *ctx)
{
    return ctx->pkey;
}

EVP_PKEY *EVP_PKEY_CTX_get0_peerkey(EVP_PKEY_CTX *ctx)
{
    return ctx->peerkey;
}

void EVP_PKEY_CTX_set_app_data(EVP_PKEY_CTX *ctx, void *data)
{
    ctx->app_data = data;
}

void *EVP_PKEY_CTX_get_app_data(EVP_PKEY_CTX *ctx)
{
    return ctx->app_data;
}

void EVP_PKEY_meth_set_init(EVP_PKEY_METHOD *pmeth,
                            int (*init) (EVP_PKEY_CTX *ctx))
{
    pmeth->init = init;
}

void EVP_PKEY_meth_set_copy(EVP_PKEY_METHOD *pmeth,
                            int (*copy) (EVP_PKEY_CTX *dst,
                                         EVP_PKEY_CTX *src))
{
    pmeth->copy = copy;
}

void EVP_PKEY_meth_set_cleanup(EVP_PKEY_METHOD *pmeth,
                               void (*cleanup) (EVP_PKEY_CTX *ctx))
{
    pmeth->cleanup = cleanup;
}

void EVP_PKEY_meth_set_paramgen(EVP_PKEY_METHOD *pmeth,
                                int (*paramgen_init) (EVP_PKEY_CTX *ctx),
                                int (*paramgen) (EVP_PKEY_CTX *ctx,
                                                 EVP_PKEY *pkey))
{
    pmeth->paramgen_init = paramgen_init;
    pmeth->paramgen = paramgen;
}

void EVP_PKEY_meth_set_keygen(EVP_PKEY_METHOD *pmeth,
                              int (*keygen_init) (EVP_PKEY_CTX *ctx),
                              int (*keygen) (EVP_PKEY_CTX *ctx,
                                             EVP_PKEY *pkey))
{
    pmeth->keygen_init = keygen_init;
    pmeth->keygen = keygen;
}

void EVP_PKEY_meth_set_sign(EVP_PKEY_METHOD *pmeth,
                            int (*sign_init) (EVP_PKEY_CTX *ctx),
                            int (*sign) (EVP_PKEY_CTX *ctx,
                                         unsigned char *sig, size_t *siglen,
                                         const unsigned char *tbs,
                                         size_t tbslen))
{
    pmeth->sign_init = sign_init;
    pmeth->sign = sign;
}

void EVP_PKEY_meth_set_verify(EVP_PKEY_METHOD *pmeth,
                              int (*verify_init) (EVP_PKEY_CTX *ctx),
                              int (*verify) (EVP_PKEY_CTX *ctx,
                                             const unsigned char *sig,
                                             size_t siglen,
                                             const unsigned char *tbs,
                                             size_t tbslen))
{
    pmeth->verify_init = verify_init;
    pmeth->verify = verify;
}

void EVP_PKEY_meth_set_verify_recover(EVP_PKEY_METHOD *pmeth,
                                      int (*verify_recover_init) (EVP_PKEY_CTX
                                                                  *ctx),
                                      int (*verify_recover) (EVP_PKEY_CTX
                                                             *ctx,
                                                             unsigned char
                                                             *sig,
                                                             size_t *siglen,
                                                             const unsigned
                                                             char *tbs,
                                                             size_t tbslen))
{
    pmeth->verify_recover_init = verify_recover_init;
    pmeth->verify_recover = verify_recover;
}

void EVP_PKEY_meth_set_signctx(EVP_PKEY_METHOD *pmeth,
                               int (*signctx_init) (EVP_PKEY_CTX *ctx,
                                                    EVP_MD_CTX *mctx),
                               int (*signctx) (EVP_PKEY_CTX *ctx,
                                               unsigned char *sig,
                                               size_t *siglen,
                                               EVP_MD_CTX *mctx))
{
    pmeth->signctx_init = signctx_init;
    pmeth->signctx = signctx;
}

void EVP_PKEY_meth_set_verifyctx(EVP_PKEY_METHOD *pmeth,
                                 int (*verifyctx_init) (EVP_PKEY_CTX *ctx,
                                                        EVP_MD_CTX *mctx),
                                 int (*verifyctx) (EVP_PKEY_CTX *ctx,
                                                   const unsigned char *sig,
                                                   int siglen,
                                                   EVP_MD_CTX *mctx))
{
    pmeth->verifyctx_init = verifyctx_init;
    pmeth->verifyctx = verifyctx;
}

void EVP_PKEY_meth_set_encrypt(EVP_PKEY_METHOD *pmeth,
                               int (*encrypt_init) (EVP_PKEY_CTX *ctx),
                               int (*encryptfn) (EVP_PKEY_CTX *ctx,
                                                 unsigned char *out,
                                                 size_t *outlen,
                                                 const unsigned char *in,
                                                 size_t inlen))
{
    pmeth->encrypt_init = encrypt_init;
    pmeth->encrypt = encryptfn;
}

void EVP_PKEY_meth_set_decrypt(EVP_PKEY_METHOD *pmeth,
                               int (*decrypt_init) (EVP_PKEY_CTX *ctx),
                               int (*decrypt) (EVP_PKEY_CTX *ctx,
                                               unsigned char *out,
                                               size_t *outlen,
                                               const unsigned char *in,
                                               size_t inlen))
{
    pmeth->decrypt_init = decrypt_init;
    pmeth->decrypt = decrypt;
}

void EVP_PKEY_meth_set_derive(EVP_PKEY_METHOD *pmeth,
                              int (*derive_init) (EVP_PKEY_CTX *ctx),
                              int (*derive) (EVP_PKEY_CTX *ctx,
                                             unsigned char *key,
                                             size_t *keylen))
{
    pmeth->derive_init = derive_init;
    pmeth->derive = derive;
}

void EVP_PKEY_meth_set_ctrl(EVP_PKEY_METHOD *pmeth,
                            int (*ctrl) (EVP_PKEY_CTX *ctx, int type, int p1,
                                         void *p2),
                            int (*ctrl_str) (EVP_PKEY_CTX *ctx,
                                             const char *type,
                                             const char *value))
{
    pmeth->ctrl = ctrl;
    pmeth->ctrl_str = ctrl_str;
}

void EVP_PKEY_meth_get_init(EVP_PKEY_METHOD *pmeth,
                            int (**pinit) (EVP_PKEY_CTX *ctx))
{
    *pinit = pmeth->init;
}

void EVP_PKEY_meth_get_copy(EVP_PKEY_METHOD *pmeth,
                            int (**pcopy) (EVP_PKEY_CTX *dst,
                                           EVP_PKEY_CTX *src))
{
    *pcopy = pmeth->copy;
}

void EVP_PKEY_meth_get_cleanup(EVP_PKEY_METHOD *pmeth,
                               void (**pcleanup) (EVP_PKEY_CTX *ctx))
{
    *pcleanup = pmeth->cleanup;
}

void EVP_PKEY_meth_get_paramgen(EVP_PKEY_METHOD *pmeth,
                                int (**pparamgen_init) (EVP_PKEY_CTX *ctx),
                                int (**pparamgen) (EVP_PKEY_CTX *ctx,
                                                   EVP_PKEY *pkey))
{
    if (pparamgen_init)
        *pparamgen_init = pmeth->paramgen_init;
    if (pparamgen)
        *pparamgen = pmeth->paramgen;
}

void EVP_PKEY_meth_get_keygen(EVP_PKEY_METHOD *pmeth,
                              int (**pkeygen_init) (EVP_PKEY_CTX *ctx),
                              int (**pkeygen) (EVP_PKEY_CTX *ctx,
                                               EVP_PKEY *pkey))
{
    if (pkeygen_init)
        *pkeygen_init = pmeth->keygen_init;
    if (pkeygen)
        *pkeygen = pmeth->keygen;
}

void EVP_PKEY_meth_get_sign(EVP_PKEY_METHOD *pmeth,
                            int (**psign_init) (EVP_PKEY_CTX *ctx),
                            int (**psign) (EVP_PKEY_CTX *ctx,
                                           unsigned char *sig, size_t *siglen,
                                           const unsigned char *tbs,
                                           size_t tbslen))
{
    if (psign_init)
        *psign_init = pmeth->sign_init;
    if (psign)
        *psign = pmeth->sign;
}

void EVP_PKEY_meth_get_verify(EVP_PKEY_METHOD *pmeth,
                              int (**pverify_init) (EVP_PKEY_CTX *ctx),
                              int (**pverify) (EVP_PKEY_CTX *ctx,
                                               const unsigned char *sig,
                                               size_t siglen,
                                               const unsigned char *tbs,
                                               size_t tbslen))
{
    if (pverify_init)
        *pverify_init = pmeth->verify_init;
    if (pverify)
        *pverify = pmeth->verify;
}

void EVP_PKEY_meth_get_verify_recover(EVP_PKEY_METHOD *pmeth,
                                      int (**pverify_recover_init) (EVP_PKEY_CTX
                                                                    *ctx),
                                      int (**pverify_recover) (EVP_PKEY_CTX
                                                               *ctx,
                                                               unsigned char
                                                               *sig,
                                                               size_t *siglen,
                                                               const unsigned
                                                               char *tbs,
                                                               size_t tbslen))
{
    if (pverify_recover_init)
        *pverify_recover_init = pmeth->verify_recover_init;
    if (pverify_recover)
        *pverify_recover = pmeth->verify_recover;
}

void EVP_PKEY_meth_get_signctx(EVP_PKEY_METHOD *pmeth,
                               int (**psignctx_init) (EVP_PKEY_CTX *ctx,
                                                      EVP_MD_CTX *mctx),
                               int (**psignctx) (EVP_PKEY_CTX *ctx,
                                                 unsigned char *sig,
                                                 size_t *siglen,
                                                 EVP_MD_CTX *mctx))
{
    if (psignctx_init)
        *psignctx_init = pmeth->signctx_init;
    if (psignctx)
        *psignctx = pmeth->signctx;
}

void EVP_PKEY_meth_get_verifyctx(EVP_PKEY_METHOD *pmeth,
                                 int (**pverifyctx_init) (EVP_PKEY_CTX *ctx,
                                                          EVP_MD_CTX *mctx),
                                 int (**pverifyctx) (EVP_PKEY_CTX *ctx,
                                                     const unsigned char *sig,
                                                     int siglen,
                                                     EVP_MD_CTX *mctx))
{
    if (pverifyctx_init)
        *pverifyctx_init = pmeth->verifyctx_init;
    if (pverifyctx)
        *pverifyctx = pmeth->verifyctx;
}

void EVP_PKEY_meth_get_encrypt(EVP_PKEY_METHOD *pmeth,
                               int (**pencrypt_init) (EVP_PKEY_CTX *ctx),
                               int (**pencryptfn) (EVP_PKEY_CTX *ctx,
                                                   unsigned char *out,
                                                   size_t *outlen,
                                                   const unsigned char *in,
                                                   size_t inlen))
{
    if (pencrypt_init)
        *pencrypt_init = pmeth->encrypt_init;
    if (pencryptfn)
        *pencryptfn = pmeth->encrypt;
}

void EVP_PKEY_meth_get_decrypt(EVP_PKEY_METHOD *pmeth,
                               int (**pdecrypt_init) (EVP_PKEY_CTX *ctx),
                               int (**pdecrypt) (EVP_PKEY_CTX *ctx,
                                                 unsigned char *out,
                                                 size_t *outlen,
                                                 const unsigned char *in,
                                                 size_t inlen))
{
    if (pdecrypt_init)
        *pdecrypt_init = pmeth->decrypt_init;
    if (pdecrypt)
        *pdecrypt = pmeth->decrypt;
}

void EVP_PKEY_meth_get_derive(EVP_PKEY_METHOD *pmeth,
                              int (**pderive_init) (EVP_PKEY_CTX *ctx),
                              int (**pderive) (EVP_PKEY_CTX *ctx,
                                               unsigned char *key,
                                               size_t *keylen))
{
    if (pderive_init)
        *pderive_init = pmeth->derive_init;
    if (pderive)
        *pderive = pmeth->derive;
}

void EVP_PKEY_meth_get_ctrl(EVP_PKEY_METHOD *pmeth,
                            int (**pctrl) (EVP_PKEY_CTX *ctx, int type, int p1,
                                           void *p2),
                            int (**pctrl_str) (EVP_PKEY_CTX *ctx,
                                               const char *type,
                                               const char *value))
{
    if (pctrl)
        *pctrl = pmeth->ctrl;
    if (pctrl_str)
        *pctrl_str = pmeth->ctrl_str;
}