static int rsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    X509_ALGOR *alg = NULL;
    switch (op) {

    case ASN1_PKEY_CTRL_PKCS7_SIGN:
        if (arg1 == 0)
            PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, NULL, &alg);
        break;

    case ASN1_PKEY_CTRL_PKCS7_ENCRYPT:
        if (arg1 == 0)
            PKCS7_RECIP_INFO_get0_alg(arg2, &alg);
        break;
#ifndef OPENSSL_NO_CMS
    case ASN1_PKEY_CTRL_CMS_SIGN:
        if (arg1 == 0)
            return rsa_cms_sign(arg2);
        else if (arg1 == 1)
            return rsa_cms_verify(arg2);
        break;

    case ASN1_PKEY_CTRL_CMS_ENVELOPE:
        if (arg1 == 0)
            return rsa_cms_encrypt(arg2);
        else if (arg1 == 1)
            return rsa_cms_decrypt(arg2);
        break;

    case ASN1_PKEY_CTRL_CMS_RI_TYPE:
        *(int *)arg2 = CMS_RECIPINFO_TRANS;
        return 1;
#endif

    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
        *(int *)arg2 = NID_sha256;
        return 1;

    default:
        return -2;

    }

    if (alg)
        X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption), V_ASN1_NULL, 0);

    return 1;

}

Unknown