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
33static EVP_PKEY *dsa_to_dh(EVP_PKEY *dh);
34static int gendh_cb(EVP_PKEY_CTX *ctx);
35
36typedef 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
44const 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
79int 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 */
363static 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
408static 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