apps/dhparam.c

   1 /*
   2  * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <openssl/opensslconf.h>
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <time.h>
  15 #include <string.h>
  16 #include "apps.h"
  17 #include "progs.h"
  18 #include <openssl/bio.h>
  19 #include <openssl/err.h>
  20 #include <openssl/bn.h>
  21 #include <openssl/dsa.h>
  22 #include <openssl/dh.h>
  23 #include <openssl/x509.h>
  24 #include <openssl/pem.h>
  25 #include <openssl/core_names.h>
  26 #include <openssl/core_dispatch.h>
  27 #include <openssl/param_build.h>
  28 #include <openssl/encoder.h>
  29 #include <openssl/decoder.h>
  30
  31 #define DEFBITS 2048
  32
  33 static EVP_PKEY *dsa_to_dh(EVP_PKEY *dh);
  34 static int gendh_cb(EVP_PKEY_CTX *ctx);
  35
  36 typedef enum OPTION_choice {
  37     OPT_COMMON,
  38     OPT_INFORM, OPT_OUTFORM, OPT_IN, OPT_OUT,
  39     OPT_ENGINE, OPT_CHECK, OPT_TEXT, OPT_NOOUT,
  40     OPT_DSAPARAM, OPT_2, OPT_3, OPT_5,
  41     OPT_R_ENUM, OPT_PROV_ENUM
  42 } OPTION_CHOICE;
  43
  44 const OPTIONS dhparam_options[] = {
  45     {OPT_HELP_STR, 1, '-', "Usage: %s [options] [numbits]\n"},
  46
  47     OPT_SECTION("General"),
  48     {"help", OPT_HELP, '-', "Display this summary"},
  49     {"check", OPT_CHECK, '-', "Check the DH parameters"},
  50 #if !defined(OPENSSL_NO_DSA) || !defined(OPENSSL_NO_DEPRECATED_3_0)
  51     {"dsaparam", OPT_DSAPARAM, '-',
  52      "Read or generate DSA parameters, convert to DH"},
  53 #endif
  54 #ifndef OPENSSL_NO_ENGINE
  55     {"engine", OPT_ENGINE, 's', "Use engine e, possibly a hardware device"},
  56 #endif
  57
  58     OPT_SECTION("Input"),
  59     {"in", OPT_IN, '<', "Input file"},
  60     {"inform", OPT_INFORM, 'F', "Input format, DER or PEM"},
  61
  62     OPT_SECTION("Output"),
  63     {"out", OPT_OUT, '>', "Output file"},
  64     {"outform", OPT_OUTFORM, 'F', "Output format, DER or PEM"},
  65     {"text", OPT_TEXT, '-', "Print a text form of the DH parameters"},
  66     {"noout", OPT_NOOUT, '-', "Don't output any DH parameters"},
  67     {"2", OPT_2, '-', "Generate parameters using 2 as the generator value"},
  68     {"3", OPT_3, '-', "Generate parameters using 3 as the generator value"},
  69     {"5", OPT_5, '-', "Generate parameters using 5 as the generator value"},
  70
  71     OPT_R_OPTIONS,
  72     OPT_PROV_OPTIONS,
  73
  74     OPT_PARAMETERS(),
  75     {"numbits", 0, 0, "Number of bits if generating parameters (optional)"},
  76     {NULL}
  77 };
  78
  79 int dhparam_main(int argc, char **argv)
  80 {
  81     BIO *in = NULL, *out = NULL;
  82     EVP_PKEY *pkey = NULL, *tmppkey = NULL;
  83     EVP_PKEY_CTX *ctx = NULL;
  84     char *infile = NULL, *outfile = NULL, *prog;
  85     ENGINE *e = NULL;
  86     int dsaparam = 0;
  87     int text = 0, ret = 1, num = 0, g = 0;
  88     int informat = FORMAT_PEM, outformat = FORMAT_PEM, check = 0, noout = 0;
  89     OPTION_CHOICE o;
  90
  91     prog = opt_init(argc, argv, dhparam_options);
  92     while ((o = opt_next()) != OPT_EOF) {
  93         switch (o) {
  94         case OPT_EOF:
  95         case OPT_ERR:
  96  opthelp:
  97             BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
  98             goto end;
  99         case OPT_HELP:
 100             opt_help(dhparam_options);
 101             ret = 0;
 102             goto end;
 103         case OPT_INFORM:
 104             if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &informat))
 105                 goto opthelp;
 106             break;
 107         case OPT_OUTFORM:
 108             if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &outformat))
 109                 goto opthelp;
 110             break;
 111         case OPT_IN:
 112             infile = opt_arg();
 113             break;
 114         case OPT_OUT:
 115             outfile = opt_arg();
 116             break;
 117         case OPT_ENGINE:
 118             e = setup_engine(opt_arg(), 0);
 119             break;
 120         case OPT_CHECK:
 121             check = 1;
 122             break;
 123         case OPT_TEXT:
 124             text = 1;
 125             break;
 126         case OPT_DSAPARAM:
 127             dsaparam = 1;
 128             break;
 129         case OPT_2:
 130             g = 2;
 131             break;
 132         case OPT_3:
 133             g = 3;
 134             break;
 135         case OPT_5:
 136             g = 5;
 137             break;
 138         case OPT_NOOUT:
 139             noout = 1;
 140             break;
 141         case OPT_R_CASES:
 142             if (!opt_rand(o))
 143                 goto end;
 144             break;
 145         case OPT_PROV_CASES:
 146             if (!opt_provider(o))
 147                 goto end;
 148             break;
 149         }
 150     }
 151
 152     /* One optional argument, bitsize to generate. */
 153     argc = opt_num_rest();
 154     argv = opt_rest();
 155     if (argc == 1) {
 156         if (!opt_int(argv[0], &num) || num <= 0)
 157             goto opthelp;
 158     } else if (argc != 0) {
 159         goto opthelp;
 160     }
 161     if (!app_RAND_load())
 162         goto end;
 163
 164     if (g && !num)
 165         num = DEFBITS;
 166
 167     if (dsaparam && g) {
 168         BIO_printf(bio_err,
 169                    "Error, generator may not be chosen for DSA parameters\n");
 170         goto end;
 171     }
 172
 173     out = bio_open_default(outfile, 'w', outformat);
 174     if (out == NULL)
 175         goto end;
 176
 177     /* DH parameters */
 178     if (num && !g)
 179         g = 2;
 180
 181     if (num) {
 182         const char *alg = dsaparam ? "DSA" : "DH";
 183
 184         ctx = EVP_PKEY_CTX_new_from_name(NULL, alg, NULL);
 185         if (ctx == NULL) {
 186             BIO_printf(bio_err,
 187                         "Error, %s param generation context allocation failed\n",
 188                         alg);
 189             goto end;
 190         }
 191         EVP_PKEY_CTX_set_cb(ctx, gendh_cb);
 192         EVP_PKEY_CTX_set_app_data(ctx, bio_err);
 193         BIO_printf(bio_err,
 194                     "Generating %s parameters, %d bit long %sprime\n",
 195                     alg, num, dsaparam ? "" : "safe ");
 196
 197         if (EVP_PKEY_paramgen_init(ctx) <= 0) {
 198             BIO_printf(bio_err,
 199                         "Error, unable to initialise %s parameters\n",
 200                         alg);
 201             goto end;
 202         }
 203
 204         if (dsaparam) {
 205             if (!EVP_PKEY_CTX_set_dsa_paramgen_bits(ctx, num)) {
 206                 BIO_printf(bio_err, "Error, unable to set DSA prime length\n");
 207                 goto end;
 208             }
 209         } else {
 210             if (!EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, num)) {
 211                 BIO_printf(bio_err, "Error, unable to set DH prime length\n");
 212                 goto end;
 213             }
 214             if (!EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, g)) {
 215                 BIO_printf(bio_err, "Error, unable to set generator\n");
 216                 goto end;
 217             }
 218         }
 219
 220         tmppkey = app_paramgen(ctx, alg);
 221         EVP_PKEY_CTX_free(ctx);
 222         ctx = NULL;
 223         if (dsaparam) {
 224             pkey = dsa_to_dh(tmppkey);
 225             if (pkey == NULL)
 226                 goto end;
 227             EVP_PKEY_free(tmppkey);
 228         } else {
 229             pkey = tmppkey;
 230         }
 231         tmppkey = NULL;
 232     } else {
 233         OSSL_DECODER_CTX *decoderctx = NULL;
 234         const char *keytype = "DH";
 235         int done;
 236
 237         in = bio_open_default(infile, 'r', informat);
 238         if (in == NULL)
 239             goto end;
 240
 241         do {
 242             /*
 243              * We assume we're done unless we explicitly want to retry and set
 244              * this to 0 below.
 245              */
 246             done = 1;
 247             /*
 248             * We set NULL for the keytype to allow any key type. We don't know
 249             * if we're going to get DH or DHX (or DSA in the event of dsaparam).
 250             * We check that we got one of those key types afterwards.
 251             */
 252             decoderctx
 253                 = OSSL_DECODER_CTX_new_for_pkey(&tmppkey,
 254                                                 (informat == FORMAT_ASN1)
 255                                                     ? "DER" : "PEM",
 256                                                 NULL,
 257                                                 (informat == FORMAT_ASN1)
 258                                                     ? keytype : NULL,
 259                                                 OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
 260                                                 NULL, NULL);
 261
 262             if (decoderctx != NULL
 263                     && !OSSL_DECODER_from_bio(decoderctx, in)
 264                     && informat == FORMAT_ASN1
 265                     && strcmp(keytype, "DH") == 0) {
 266                 /*
 267                 * When reading DER we explicitly state the expected keytype
 268                 * because, unlike PEM, there is no header to declare what
 269                 * the contents of the DER file are. The decoders just try
 270                 * and guess. Unfortunately with DHX key types they may guess
 271                 * wrong and think we have a DSA keytype. Therefore we try
 272                 * both DH and DHX sequentially.
 273                 */
 274                 keytype = "DHX";
 275                 /*
 276                  * BIO_reset() returns 0 for success for file BIOs only!!!
 277                  * This won't work for stdin (and never has done)
 278                  */
 279                 if (BIO_reset(in) == 0)
 280                     done = 0;
 281             }
 282             OSSL_DECODER_CTX_free(decoderctx);
 283         } while (!done);
 284         if (tmppkey == NULL) {
 285             BIO_printf(bio_err, "Error, unable to load parameters\n");
 286             goto end;
 287         }
 288
 289         if (dsaparam) {
 290             if (!EVP_PKEY_is_a(tmppkey, "DSA")) {
 291                 BIO_printf(bio_err, "Error, unable to load DSA parameters\n");
 292                 goto end;
 293             }
 294             pkey = dsa_to_dh(tmppkey);
 295             if (pkey == NULL)
 296                 goto end;
 297         } else {
 298             if (!EVP_PKEY_is_a(tmppkey, "DH")
 299                     && !EVP_PKEY_is_a(tmppkey, "DHX")) {
 300                 BIO_printf(bio_err, "Error, unable to load DH parameters\n");
 301                 goto end;
 302             }
 303             pkey = tmppkey;
 304             tmppkey = NULL;
 305         }
 306     }
 307
 308     if (text)
 309         EVP_PKEY_print_params(out, pkey, 4, NULL);
 310
 311     if (check) {
 312         ctx = EVP_PKEY_CTX_new_from_pkey(NULL, pkey, NULL);
 313         if (ctx == NULL) {
 314             BIO_printf(bio_err, "Error, failed to check DH parameters\n");
 315             goto end;
 316         }
 317         if (!EVP_PKEY_param_check(ctx)) {
 318             BIO_printf(bio_err, "Error, invalid parameters generated\n");
 319             goto end;
 320         }
 321         BIO_printf(bio_err, "DH parameters appear to be ok.\n");
 322     }
 323
 324     if (!noout) {
 325         OSSL_ENCODER_CTX *ectx =
 326             OSSL_ENCODER_CTX_new_for_pkey(pkey,
 327                                           OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
 328                                           outformat == FORMAT_ASN1
 329                                               ? "DER" : "PEM",
 330                                           NULL, NULL);
 331
 332         if (ectx == NULL || !OSSL_ENCODER_to_bio(ectx, out)) {
 333             OSSL_ENCODER_CTX_free(ectx);
 334             BIO_printf(bio_err, "Error, unable to write DH parameters\n");
 335             goto end;
 336         }
 337         OSSL_ENCODER_CTX_free(ectx);
 338     }
 339     ret = 0;
 340  end:
 341     if (ret != 0)
 342         ERR_print_errors(bio_err);
 343     BIO_free(in);
 344     BIO_free_all(out);
 345     EVP_PKEY_free(pkey);
 346     EVP_PKEY_free(tmppkey);
 347     EVP_PKEY_CTX_free(ctx);
 348     release_engine(e);
 349     return ret;
 350 }
 351
 352 /*
 353  * Historically we had the low level call DSA_dup_DH() to do this.
 354  * That is now deprecated with no replacement. Since we still need to do this
 355  * for backwards compatibility reasons, we do it "manually".
 356  */
 357 static EVP_PKEY *dsa_to_dh(EVP_PKEY *dh)
 358 {
 359     OSSL_PARAM_BLD *tmpl = NULL;
 360     OSSL_PARAM *params = NULL;
 361     BIGNUM *bn_p = NULL, *bn_q = NULL, *bn_g = NULL;
 362     EVP_PKEY_CTX *ctx = NULL;
 363     EVP_PKEY *pkey = NULL;
 364
 365     if (!EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_P, &bn_p)
 366             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_Q, &bn_q)
 367             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_G, &bn_g)) {
 368         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
 369         goto err;
 370     }
 371
 372     if ((tmpl = OSSL_PARAM_BLD_new()) == NULL
 373             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P,
 374                                         bn_p)
 375             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_Q,
 376                                         bn_q)
 377             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_G,
 378                                         bn_g)
 379             || (params = OSSL_PARAM_BLD_to_param(tmpl)) == NULL) {
 380         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
 381         goto err;
 382     }
 383
 384     ctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
 385     if (ctx == NULL
 386             || EVP_PKEY_fromdata_init(ctx) <= 0
 387             || EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEY_PARAMETERS, params) <= 0) {
 388         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
 389         goto err;
 390     }
 391
 392  err:
 393     EVP_PKEY_CTX_free(ctx);
 394     OSSL_PARAM_free(params);
 395     OSSL_PARAM_BLD_free(tmpl);
 396     BN_free(bn_p);
 397     BN_free(bn_q);
 398     BN_free(bn_g);
 399     return pkey;
 400 }
 401
 402 static int gendh_cb(EVP_PKEY_CTX *ctx)
 403 {
 404     int p = EVP_PKEY_CTX_get_keygen_info(ctx, 0);
 405     BIO *b = EVP_PKEY_CTX_get_app_data(ctx);
 406     static const char symbols[] = ".+*\n";
 407     char c = (p >= 0 && (size_t)p < sizeof(symbols) - 1) ? symbols[p] : '?';
 408
 409     BIO_write(b, &c, 1);
 410     (void)BIO_flush(b);
 411     return 1;
 412 }