xref: /freebsd/crypto/openssl/apps/dhparam.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*
2  * Copyright 1995-2022 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         if (infile != NULL) {
185             BIO_printf(bio_err, "Warning, input file %s ignored\n", infile);
186         }
187 
188         ctx = EVP_PKEY_CTX_new_from_name(app_get0_libctx(), alg, app_get0_propq());
189         if (ctx == NULL) {
190             BIO_printf(bio_err,
191                         "Error, %s param generation context allocation failed\n",
192                         alg);
193             goto end;
194         }
195         EVP_PKEY_CTX_set_cb(ctx, gendh_cb);
196         EVP_PKEY_CTX_set_app_data(ctx, bio_err);
197         BIO_printf(bio_err,
198                     "Generating %s parameters, %d bit long %sprime\n",
199                     alg, num, dsaparam ? "" : "safe ");
200 
201         if (EVP_PKEY_paramgen_init(ctx) <= 0) {
202             BIO_printf(bio_err,
203                         "Error, unable to initialise %s parameters\n",
204                         alg);
205             goto end;
206         }
207 
208         if (dsaparam) {
209             if (EVP_PKEY_CTX_set_dsa_paramgen_bits(ctx, num) <= 0) {
210                 BIO_printf(bio_err, "Error, unable to set DSA prime length\n");
211                 goto end;
212             }
213         } else {
214             if (EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, num) <= 0) {
215                 BIO_printf(bio_err, "Error, unable to set DH prime length\n");
216                 goto end;
217             }
218             if (EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, g) <= 0) {
219                 BIO_printf(bio_err, "Error, unable to set generator\n");
220                 goto end;
221             }
222         }
223 
224         tmppkey = app_paramgen(ctx, alg);
225         EVP_PKEY_CTX_free(ctx);
226         ctx = NULL;
227         if (dsaparam) {
228             pkey = dsa_to_dh(tmppkey);
229             if (pkey == NULL)
230                 goto end;
231             EVP_PKEY_free(tmppkey);
232         } else {
233             pkey = tmppkey;
234         }
235         tmppkey = NULL;
236     } else {
237         OSSL_DECODER_CTX *decoderctx = NULL;
238         const char *keytype = "DH";
239         int done;
240 
241         in = bio_open_default(infile, 'r', informat);
242         if (in == NULL)
243             goto end;
244 
245         do {
246             /*
247              * We assume we're done unless we explicitly want to retry and set
248              * this to 0 below.
249              */
250             done = 1;
251             /*
252             * We set NULL for the keytype to allow any key type. We don't know
253             * if we're going to get DH or DHX (or DSA in the event of dsaparam).
254             * We check that we got one of those key types afterwards.
255             */
256             decoderctx
257                 = OSSL_DECODER_CTX_new_for_pkey(&tmppkey,
258                                                 (informat == FORMAT_ASN1)
259                                                     ? "DER" : "PEM",
260                                                 NULL,
261                                                 (informat == FORMAT_ASN1)
262                                                     ? keytype : NULL,
263                                                 OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
264                                                 NULL, NULL);
265 
266             if (decoderctx != NULL
267                     && !OSSL_DECODER_from_bio(decoderctx, in)
268                     && informat == FORMAT_ASN1
269                     && strcmp(keytype, "DH") == 0) {
270                 /*
271                 * When reading DER we explicitly state the expected keytype
272                 * because, unlike PEM, there is no header to declare what
273                 * the contents of the DER file are. The decoders just try
274                 * and guess. Unfortunately with DHX key types they may guess
275                 * wrong and think we have a DSA keytype. Therefore we try
276                 * both DH and DHX sequentially.
277                 */
278                 keytype = "DHX";
279                 /*
280                  * BIO_reset() returns 0 for success for file BIOs only!!!
281                  * This won't work for stdin (and never has done)
282                  */
283                 if (BIO_reset(in) == 0)
284                     done = 0;
285             }
286             OSSL_DECODER_CTX_free(decoderctx);
287         } while (!done);
288         if (tmppkey == NULL) {
289             BIO_printf(bio_err, "Error, unable to load parameters\n");
290             goto end;
291         }
292 
293         if (dsaparam) {
294             if (!EVP_PKEY_is_a(tmppkey, "DSA")) {
295                 BIO_printf(bio_err, "Error, unable to load DSA parameters\n");
296                 goto end;
297             }
298             pkey = dsa_to_dh(tmppkey);
299             if (pkey == NULL)
300                 goto end;
301         } else {
302             if (!EVP_PKEY_is_a(tmppkey, "DH")
303                     && !EVP_PKEY_is_a(tmppkey, "DHX")) {
304                 BIO_printf(bio_err, "Error, unable to load DH parameters\n");
305                 goto end;
306             }
307             pkey = tmppkey;
308             tmppkey = NULL;
309         }
310     }
311 
312     if (text)
313         EVP_PKEY_print_params(out, pkey, 4, NULL);
314 
315     if (check) {
316         ctx = EVP_PKEY_CTX_new_from_pkey(app_get0_libctx(), pkey, app_get0_propq());
317         if (ctx == NULL) {
318             BIO_printf(bio_err, "Error, failed to check DH parameters\n");
319             goto end;
320         }
321         if (EVP_PKEY_param_check(ctx) <= 0) {
322             BIO_printf(bio_err, "Error, invalid parameters generated\n");
323             goto end;
324         }
325         BIO_printf(bio_err, "DH parameters appear to be ok.\n");
326     }
327 
328     if (!noout) {
329         OSSL_ENCODER_CTX *ectx =
330             OSSL_ENCODER_CTX_new_for_pkey(pkey,
331                                           OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
332                                           outformat == FORMAT_ASN1
333                                               ? "DER" : "PEM",
334                                           NULL, NULL);
335 
336         if (ectx == NULL || !OSSL_ENCODER_to_bio(ectx, out)) {
337             OSSL_ENCODER_CTX_free(ectx);
338             BIO_printf(bio_err, "Error, unable to write DH parameters\n");
339             goto end;
340         }
341         OSSL_ENCODER_CTX_free(ectx);
342     }
343     ret = 0;
344  end:
345     if (ret != 0)
346         ERR_print_errors(bio_err);
347     BIO_free(in);
348     BIO_free_all(out);
349     EVP_PKEY_free(pkey);
350     EVP_PKEY_free(tmppkey);
351     EVP_PKEY_CTX_free(ctx);
352     release_engine(e);
353     return ret;
354 }
355 
356 /*
357  * Historically we had the low level call DSA_dup_DH() to do this.
358  * That is now deprecated with no replacement. Since we still need to do this
359  * for backwards compatibility reasons, we do it "manually".
360  */
361 static EVP_PKEY *dsa_to_dh(EVP_PKEY *dh)
362 {
363     OSSL_PARAM_BLD *tmpl = NULL;
364     OSSL_PARAM *params = NULL;
365     BIGNUM *bn_p = NULL, *bn_q = NULL, *bn_g = NULL;
366     EVP_PKEY_CTX *ctx = NULL;
367     EVP_PKEY *pkey = NULL;
368 
369     if (!EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_P, &bn_p)
370             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_Q, &bn_q)
371             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_G, &bn_g)) {
372         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
373         goto err;
374     }
375 
376     if ((tmpl = OSSL_PARAM_BLD_new()) == NULL
377             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P,
378                                         bn_p)
379             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_Q,
380                                         bn_q)
381             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_G,
382                                         bn_g)
383             || (params = OSSL_PARAM_BLD_to_param(tmpl)) == NULL) {
384         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
385         goto err;
386     }
387 
388     ctx = EVP_PKEY_CTX_new_from_name(app_get0_libctx(), "DHX", app_get0_propq());
389     if (ctx == NULL
390             || EVP_PKEY_fromdata_init(ctx) <= 0
391             || EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEY_PARAMETERS, params) <= 0) {
392         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
393         goto err;
394     }
395 
396  err:
397     EVP_PKEY_CTX_free(ctx);
398     OSSL_PARAM_free(params);
399     OSSL_PARAM_BLD_free(tmpl);
400     BN_free(bn_p);
401     BN_free(bn_q);
402     BN_free(bn_g);
403     return pkey;
404 }
405 
406 static int gendh_cb(EVP_PKEY_CTX *ctx)
407 {
408     int p = EVP_PKEY_CTX_get_keygen_info(ctx, 0);
409     BIO *b = EVP_PKEY_CTX_get_app_data(ctx);
410     static const char symbols[] = ".+*\n";
411     char c = (p >= 0 && (size_t)p < sizeof(symbols) - 1) ? symbols[p] : '?';
412 
413     BIO_write(b, &c, 1);
414     (void)BIO_flush(b);
415     return 1;
416 }
417