xref: /freebsd/crypto/openssl/apps/dhparam.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1 /*
2  * Copyright 1995-2023 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         if (tmppkey == NULL)
226             goto end;
227         EVP_PKEY_CTX_free(ctx);
228         ctx = NULL;
229         if (dsaparam) {
230             pkey = dsa_to_dh(tmppkey);
231             if (pkey == NULL)
232                 goto end;
233             EVP_PKEY_free(tmppkey);
234         } else {
235             pkey = tmppkey;
236         }
237         tmppkey = NULL;
238     } else {
239         OSSL_DECODER_CTX *decoderctx = NULL;
240         const char *keytype = "DH";
241         int done;
242 
243         in = bio_open_default(infile, 'r', informat);
244         if (in == NULL)
245             goto end;
246 
247         do {
248             /*
249              * We assume we're done unless we explicitly want to retry and set
250              * this to 0 below.
251              */
252             done = 1;
253             /*
254             * We set NULL for the keytype to allow any key type. We don't know
255             * if we're going to get DH or DHX (or DSA in the event of dsaparam).
256             * We check that we got one of those key types afterwards.
257             */
258             decoderctx
259                 = OSSL_DECODER_CTX_new_for_pkey(&tmppkey,
260                                                 (informat == FORMAT_ASN1)
261                                                     ? "DER" : "PEM",
262                                                 NULL,
263                                                 (informat == FORMAT_ASN1)
264                                                     ? keytype : NULL,
265                                                 OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
266                                                 NULL, NULL);
267 
268             if (decoderctx != NULL
269                     && !OSSL_DECODER_from_bio(decoderctx, in)
270                     && informat == FORMAT_ASN1
271                     && strcmp(keytype, "DH") == 0) {
272                 /*
273                 * When reading DER we explicitly state the expected keytype
274                 * because, unlike PEM, there is no header to declare what
275                 * the contents of the DER file are. The decoders just try
276                 * and guess. Unfortunately with DHX key types they may guess
277                 * wrong and think we have a DSA keytype. Therefore we try
278                 * both DH and DHX sequentially.
279                 */
280                 keytype = "DHX";
281                 /*
282                  * BIO_reset() returns 0 for success for file BIOs only!!!
283                  * This won't work for stdin (and never has done)
284                  */
285                 if (BIO_reset(in) == 0)
286                     done = 0;
287             }
288             OSSL_DECODER_CTX_free(decoderctx);
289         } while (!done);
290         if (tmppkey == NULL) {
291             BIO_printf(bio_err, "Error, unable to load parameters\n");
292             goto end;
293         }
294 
295         if (dsaparam) {
296             if (!EVP_PKEY_is_a(tmppkey, "DSA")) {
297                 BIO_printf(bio_err, "Error, unable to load DSA parameters\n");
298                 goto end;
299             }
300             pkey = dsa_to_dh(tmppkey);
301             if (pkey == NULL)
302                 goto end;
303         } else {
304             if (!EVP_PKEY_is_a(tmppkey, "DH")
305                     && !EVP_PKEY_is_a(tmppkey, "DHX")) {
306                 BIO_printf(bio_err, "Error, unable to load DH parameters\n");
307                 goto end;
308             }
309             pkey = tmppkey;
310             tmppkey = NULL;
311         }
312     }
313 
314     if (text)
315         EVP_PKEY_print_params(out, pkey, 4, NULL);
316 
317     if (check) {
318         ctx = EVP_PKEY_CTX_new_from_pkey(app_get0_libctx(), pkey, app_get0_propq());
319         if (ctx == NULL) {
320             BIO_printf(bio_err, "Error, failed to check DH parameters\n");
321             goto end;
322         }
323         if (EVP_PKEY_param_check(ctx) <= 0) {
324             BIO_printf(bio_err, "Error, invalid parameters generated\n");
325             goto end;
326         }
327         BIO_printf(bio_err, "DH parameters appear to be ok.\n");
328     }
329 
330     if (!noout) {
331         OSSL_ENCODER_CTX *ectx =
332             OSSL_ENCODER_CTX_new_for_pkey(pkey,
333                                           OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
334                                           outformat == FORMAT_ASN1
335                                               ? "DER" : "PEM",
336                                           NULL, NULL);
337 
338         if (ectx == NULL || !OSSL_ENCODER_to_bio(ectx, out)) {
339             OSSL_ENCODER_CTX_free(ectx);
340             BIO_printf(bio_err, "Error, unable to write DH parameters\n");
341             goto end;
342         }
343         OSSL_ENCODER_CTX_free(ectx);
344     }
345     ret = 0;
346  end:
347     if (ret != 0)
348         ERR_print_errors(bio_err);
349     BIO_free(in);
350     BIO_free_all(out);
351     EVP_PKEY_free(pkey);
352     EVP_PKEY_free(tmppkey);
353     EVP_PKEY_CTX_free(ctx);
354     release_engine(e);
355     return ret;
356 }
357 
358 /*
359  * Historically we had the low level call DSA_dup_DH() to do this.
360  * That is now deprecated with no replacement. Since we still need to do this
361  * for backwards compatibility reasons, we do it "manually".
362  */
363 static EVP_PKEY *dsa_to_dh(EVP_PKEY *dh)
364 {
365     OSSL_PARAM_BLD *tmpl = NULL;
366     OSSL_PARAM *params = NULL;
367     BIGNUM *bn_p = NULL, *bn_q = NULL, *bn_g = NULL;
368     EVP_PKEY_CTX *ctx = NULL;
369     EVP_PKEY *pkey = NULL;
370 
371     if (!EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_P, &bn_p)
372             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_Q, &bn_q)
373             || !EVP_PKEY_get_bn_param(dh, OSSL_PKEY_PARAM_FFC_G, &bn_g)) {
374         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
375         goto err;
376     }
377 
378     if ((tmpl = OSSL_PARAM_BLD_new()) == NULL
379             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P,
380                                         bn_p)
381             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_Q,
382                                         bn_q)
383             || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_G,
384                                         bn_g)
385             || (params = OSSL_PARAM_BLD_to_param(tmpl)) == NULL) {
386         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
387         goto err;
388     }
389 
390     ctx = EVP_PKEY_CTX_new_from_name(app_get0_libctx(), "DHX", app_get0_propq());
391     if (ctx == NULL
392             || EVP_PKEY_fromdata_init(ctx) <= 0
393             || EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEY_PARAMETERS, params) <= 0) {
394         BIO_printf(bio_err, "Error, failed to set DH parameters\n");
395         goto err;
396     }
397 
398  err:
399     EVP_PKEY_CTX_free(ctx);
400     OSSL_PARAM_free(params);
401     OSSL_PARAM_BLD_free(tmpl);
402     BN_free(bn_p);
403     BN_free(bn_q);
404     BN_free(bn_g);
405     return pkey;
406 }
407 
408 static int gendh_cb(EVP_PKEY_CTX *ctx)
409 {
410     int p = EVP_PKEY_CTX_get_keygen_info(ctx, 0);
411     BIO *b = EVP_PKEY_CTX_get_app_data(ctx);
412     static const char symbols[] = ".+*\n";
413     char c = (p >= 0 && (size_t)p < sizeof(symbols) - 1) ? symbols[p] : '?';
414 
415     BIO_write(b, &c, 1);
416     (void)BIO_flush(b);
417     return 1;
418 }
419