/*

 * Copyright 1995-2020 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 <openssl/opensslconf.h>

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#include <string.h>

#include "apps.h"

#include "progs.h"

#include <openssl/bio.h>

#include <openssl/err.h>

#include <openssl/bn.h>

#include <openssl/dh.h>

#include <openssl/x509.h>

#include <openssl/pem.h>

#ifndef OPENSSL_NO_DSA

# include <openssl/dsa.h>

#endif

#define DEFBITS 2048

static int dh_cb(int p, int n, BN_GENCB *cb);

typedef enum OPTION_choice {

    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,

    OPT_INFORM, OPT_OUTFORM, OPT_IN, OPT_OUT,

    OPT_ENGINE, OPT_CHECK, OPT_TEXT, OPT_NOOUT,

    OPT_DSAPARAM, OPT_C, OPT_2, OPT_5,

    OPT_R_ENUM

} OPTION_CHOICE;

const OPTIONS dhparam_options[] = {

    {OPT_HELP_STR, 1, '-', "Usage: %s [flags] [numbits]\n"},

    {OPT_HELP_STR, 1, '-', "Valid options are:\n"},

    {"help", OPT_HELP, '-', "Display this summary"},

    {"in", OPT_IN, '<', "Input file"},

    {"inform", OPT_INFORM, 'F', "Input format, DER or PEM"},

    {"outform", OPT_OUTFORM, 'F', "Output format, DER or PEM"},

    {"out", OPT_OUT, '>', "Output file"},

    {"check", OPT_CHECK, '-', "Check the DH parameters"},

    {"text", OPT_TEXT, '-', "Print a text form of the DH parameters"},

    {"noout", OPT_NOOUT, '-', "Don't output any DH parameters"},

    OPT_R_OPTIONS,

    {"C", OPT_C, '-', "Print C code"},

    {"2", OPT_2, '-', "Generate parameters using 2 as the generator value"},

    {"5", OPT_5, '-', "Generate parameters using 5 as the generator value"},

#ifndef OPENSSL_NO_DSA

    {"dsaparam", OPT_DSAPARAM, '-',

     "Read or generate DSA parameters, convert to DH"},

#endif

#ifndef OPENSSL_NO_ENGINE

    {"engine", OPT_ENGINE, 's', "Use engine e, possibly a hardware device"},

#endif

    {NULL}

};

int dhparam_main(int argc, char **argv)

{

    BIO *in = NULL, *out = NULL;

    DH *dh = NULL;

    char *infile = NULL, *outfile = NULL, *prog;

    ENGINE *e = NULL;

#ifndef OPENSSL_NO_DSA

    int dsaparam = 0;

#endif

    int i, text = 0, C = 0, ret = 1, num = 0, g = 0;

    int informat = FORMAT_PEM, outformat = FORMAT_PEM, check = 0, noout = 0;

    OPTION_CHOICE o;

    prog = opt_init(argc, argv, dhparam_options);

    while ((o = opt_next()) != OPT_EOF) {

        switch (o) {

        case OPT_EOF:

        case OPT_ERR:

 opthelp:

            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);

            goto end;

        case OPT_HELP:

            opt_help(dhparam_options);

            ret = 0;

            goto end;

        case OPT_INFORM:

            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &informat))

                goto opthelp;

            break;

        case OPT_OUTFORM:

            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &outformat))

                goto opthelp;

            break;

        case OPT_IN:

            infile = opt_arg();

            break;

        case OPT_OUT:

            outfile = opt_arg();

            break;

        case OPT_ENGINE:

            e = setup_engine(opt_arg(), 0);

            break;

        case OPT_CHECK:

            check = 1;

            break;

        case OPT_TEXT:

            text = 1;

            break;

        case OPT_DSAPARAM:

#ifndef OPENSSL_NO_DSA

            dsaparam = 1;

#endif

            break;

        case OPT_C:

            C = 1;

            break;

        case OPT_2:

            g = 2;

            break;

        case OPT_5:

            g = 5;

            break;

        case OPT_NOOUT:

            noout = 1;

            break;

        case OPT_R_CASES:

            if (!opt_rand(o))

                goto end;

            break;

        }

    }

    argc = opt_num_rest();

    argv = opt_rest();

    if (argv[0] != NULL && (!opt_int(argv[0], &num) || num <= 0))

        goto end;

    if (g && !num)

        num = DEFBITS;

#ifndef OPENSSL_NO_DSA

    if (dsaparam && g) {

        BIO_printf(bio_err,

                   "generator may not be chosen for DSA parameters\n");

        goto end;

    }

#endif

    out = bio_open_default(outfile, 'w', outformat);

    if (out == NULL)

        goto end;

    /* DH parameters */

    if (num && !g)

        g = 2;

    if (num) {

        BN_GENCB *cb;

        cb = BN_GENCB_new();

        if (cb == NULL) {

            ERR_print_errors(bio_err);

            goto end;

        }

        BN_GENCB_set(cb, dh_cb, bio_err);

#ifndef OPENSSL_NO_DSA

        if (dsaparam) {

            DSA *dsa = DSA_new();

            BIO_printf(bio_err,

                       "Generating DSA parameters, %d bit long prime\n", num);

            if (dsa == NULL

                || !DSA_generate_parameters_ex(dsa, num, NULL, 0, NULL, NULL,

                                               cb)) {

                DSA_free(dsa);

                BN_GENCB_free(cb);

                ERR_print_errors(bio_err);

                goto end;

            }

            dh = DSA_dup_DH(dsa);

            DSA_free(dsa);

            if (dh == NULL) {

                BN_GENCB_free(cb);

                ERR_print_errors(bio_err);

                goto end;

            }

        } else

#endif

        {

            dh = DH_new();

            BIO_printf(bio_err,

                       "Generating DH parameters, %d bit long safe prime, generator %d\n",

                       num, g);

            BIO_printf(bio_err, "This is going to take a long time\n");

            if (dh == NULL || !DH_generate_parameters_ex(dh, num, g, cb)) {

                BN_GENCB_free(cb);

                ERR_print_errors(bio_err);

                goto end;

            }

        }

        BN_GENCB_free(cb);

    } else {

        in = bio_open_default(infile, 'r', informat);

        if (in == NULL)

            goto end;

#ifndef OPENSSL_NO_DSA

        if (dsaparam) {

            DSA *dsa;

            if (informat == FORMAT_ASN1)

                dsa = d2i_DSAparams_bio(in, NULL);

            else                /* informat == FORMAT_PEM */

                dsa = PEM_read_bio_DSAparams(in, NULL, NULL, NULL);

            if (dsa == NULL) {

                BIO_printf(bio_err, "unable to load DSA parameters\n");

                ERR_print_errors(bio_err);

                goto end;

            }

            dh = DSA_dup_DH(dsa);

            DSA_free(dsa);

            if (dh == NULL) {

                ERR_print_errors(bio_err);

                goto end;

            }

        } else

#endif

        {

            if (informat == FORMAT_ASN1) {

                /*

                 * We have no PEM header to determine what type of DH params it

                 * is. We'll just try both.

                 */

                dh = d2i_DHparams_bio(in, NULL);

                /* BIO_reset() returns 0 for success for file BIOs only!!! */

                if (dh == NULL && BIO_reset(in) == 0)

                    dh = d2i_DHxparams_bio(in, NULL);

            } else {

                /* informat == FORMAT_PEM */

                dh = PEM_read_bio_DHparams(in, NULL, NULL, NULL);

            }

            if (dh == NULL) {

                BIO_printf(bio_err, "unable to load DH parameters\n");

                ERR_print_errors(bio_err);

                goto end;

            }

        }

        /* dh != NULL */

    }

    if (text) {

        DHparams_print(out, dh);

    }

    if (check) {

        if (!DH_check(dh, &i)) {

            ERR_print_errors(bio_err);

            goto end;

        }

        if (i & DH_CHECK_P_NOT_PRIME)

            BIO_printf(bio_err, "WARNING: p value is not prime\n");

        if (i & DH_CHECK_P_NOT_SAFE_PRIME)

            BIO_printf(bio_err, "WARNING: p value is not a safe prime\n");

        if (i & DH_CHECK_Q_NOT_PRIME)

            BIO_printf(bio_err, "WARNING: q value is not a prime\n");

        if (i & DH_CHECK_INVALID_Q_VALUE)

            BIO_printf(bio_err, "WARNING: q value is invalid\n");

        if (i & DH_CHECK_INVALID_J_VALUE)

            BIO_printf(bio_err, "WARNING: j value is invalid\n");

        if (i & DH_UNABLE_TO_CHECK_GENERATOR)

            BIO_printf(bio_err,

                       "WARNING: unable to check the generator value\n");

        if (i & DH_NOT_SUITABLE_GENERATOR)

            BIO_printf(bio_err, "WARNING: the g value is not a generator\n");

        if (i == 0)

            BIO_printf(bio_err, "DH parameters appear to be ok.\n");

        if (num != 0 && i != 0) {

            /*

             * We have generated parameters but DH_check() indicates they are

             * invalid! This should never happen!

             */

            BIO_printf(bio_err, "ERROR: Invalid parameters generated\n");

            goto end;

        }

    }

    if (C) {

        unsigned char *data;

        int len, bits;

        const BIGNUM *pbn, *gbn;

        len = DH_size(dh);

        bits = DH_bits(dh);

        DH_get0_pqg(dh, &pbn, NULL, &gbn;;

        data = app_malloc(len, "print a BN");

        BIO_printf(out, "static DH *get_dh%d(void)\n{\n", bits);

        print_bignum_var(out, pbn, "dhp", bits, data);

        print_bignum_var(out, gbn, "dhg", bits, data);

        BIO_printf(out, "    DH *dh = DH_new();\n"

                        "    BIGNUM *p, *g;\n"

                        "\n"

                        "    if (dh == NULL)\n"

                        "        return NULL;\n");

        BIO_printf(out, "    p = BN_bin2bn(dhp_%d, sizeof(dhp_%d), NULL);\n",

                   bits, bits);

        BIO_printf(out, "    g = BN_bin2bn(dhg_%d, sizeof(dhg_%d), NULL);\n",

                   bits, bits);

        BIO_printf(out, "    if (p == NULL || g == NULL\n"

                        "            || !DH_set0_pqg(dh, p, NULL, g)) {\n"

                        "        DH_free(dh);\n"

                        "        BN_free(p);\n"

                        "        BN_free(g);\n"

                        "        return NULL;\n"

                        "    }\n");

        if (DH_get_length(dh) > 0)

            BIO_printf(out,

                        "    if (!DH_set_length(dh, %ld)) {\n"

                        "        DH_free(dh);\n"

                        "        return NULL;\n"

                        "    }\n", DH_get_length(dh));

        BIO_printf(out, "    return dh;\n}\n");

        OPENSSL_free(data);

    }

    if (!noout) {

        const BIGNUM *q;

        DH_get0_pqg(dh, NULL, &q, NULL);

        if (outformat == FORMAT_ASN1) {

            if (q != NULL)

                i = i2d_DHxparams_bio(out, dh);

            else

                i = i2d_DHparams_bio(out, dh);

        } else if (q != NULL) {

            i = PEM_write_bio_DHxparams(out, dh);

        } else {

            i = PEM_write_bio_DHparams(out, dh);

        }

        if (!i) {

            BIO_printf(bio_err, "unable to write DH parameters\n");

            ERR_print_errors(bio_err);

            goto end;

        }

    }

    ret = 0;

 end:

    BIO_free(in);

    BIO_free_all(out);

    DH_free(dh);

    release_engine(e);

    return ret;

}

static int dh_cb(int p, int n, BN_GENCB *cb)

{

    static const char symbols[] = ".+*\n";

    char c = (p >= 0 && (size_t)p < sizeof(symbols) - 1) ? symbols[p] : '?';

    BIO_write(BN_GENCB_get_arg(cb), &c, 1);

    (void)BIO_flush(BN_GENCB_get_arg(cb));

    return 1;

}