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1 /*
2  *  Certificate generation and signing
3  *
4  *  Copyright The Mbed TLS Contributors
5  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6  *
7  *  This file is provided under the Apache License 2.0, or the
8  *  GNU General Public License v2.0 or later.
9  *
10  *  **********
11  *  Apache License 2.0:
12  *
13  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
14  *  not use this file except in compliance with the License.
15  *  You may obtain a copy of the License at
16  *
17  *  http://www.apache.org/licenses/LICENSE-2.0
18  *
19  *  Unless required by applicable law or agreed to in writing, software
20  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
21  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22  *  See the License for the specific language governing permissions and
23  *  limitations under the License.
24  *
25  *  **********
26  *
27  *  **********
28  *  GNU General Public License v2.0 or later:
29  *
30  *  This program is free software; you can redistribute it and/or modify
31  *  it under the terms of the GNU General Public License as published by
32  *  the Free Software Foundation; either version 2 of the License, or
33  *  (at your option) any later version.
34  *
35  *  This program is distributed in the hope that it will be useful,
36  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
37  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
38  *  GNU General Public License for more details.
39  *
40  *  You should have received a copy of the GNU General Public License along
41  *  with this program; if not, write to the Free Software Foundation, Inc.,
42  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
43  *
44  *  **********
45  */
46 
47 #if !defined(MBEDTLS_CONFIG_FILE)
48 #include "mbedtls/config.h"
49 #else
50 #include MBEDTLS_CONFIG_FILE
51 #endif
52 
53 #if defined(MBEDTLS_PLATFORM_C)
54 #include "mbedtls/platform.h"
55 #else
56 #include <stdio.h>
57 #include <stdlib.h>
58 #define mbedtls_printf          printf
59 #define mbedtls_exit            exit
60 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
61 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
62 #endif /* MBEDTLS_PLATFORM_C */
63 
64 #if !defined(MBEDTLS_X509_CRT_WRITE_C) || \
65     !defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_FS_IO) || \
66     !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
67     !defined(MBEDTLS_ERROR_C) || !defined(MBEDTLS_SHA256_C) || \
68     !defined(MBEDTLS_PEM_WRITE_C)
main(void)69 int main( void )
70 {
71     mbedtls_printf( "MBEDTLS_X509_CRT_WRITE_C and/or MBEDTLS_X509_CRT_PARSE_C and/or "
72             "MBEDTLS_FS_IO and/or MBEDTLS_SHA256_C and/or "
73             "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
74             "MBEDTLS_ERROR_C not defined.\n");
75     mbedtls_exit( 0 );
76 }
77 #else
78 
79 #include "mbedtls/x509_crt.h"
80 #include "mbedtls/x509_csr.h"
81 #include "mbedtls/entropy.h"
82 #include "mbedtls/ctr_drbg.h"
83 #include "mbedtls/md.h"
84 #include "mbedtls/error.h"
85 
86 #include <stdio.h>
87 #include <stdlib.h>
88 #include <string.h>
89 
90 #if defined(MBEDTLS_X509_CSR_PARSE_C)
91 #define USAGE_CSR                                                           \
92     "    request_file=%%s         default: (empty)\n"                           \
93     "                            If request_file is specified, subject_key,\n"  \
94     "                            subject_pwd and subject_name are ignored!\n"
95 #else
96 #define USAGE_CSR ""
97 #endif /* MBEDTLS_X509_CSR_PARSE_C */
98 
99 #define DFL_ISSUER_CRT          ""
100 #define DFL_REQUEST_FILE        ""
101 #define DFL_SUBJECT_KEY         "subject.key"
102 #define DFL_ISSUER_KEY          "ca.key"
103 #define DFL_SUBJECT_PWD         ""
104 #define DFL_ISSUER_PWD          ""
105 #define DFL_OUTPUT_FILENAME     "cert.crt"
106 #define DFL_SUBJECT_NAME        "CN=Cert,O=mbed TLS,C=UK"
107 #define DFL_ISSUER_NAME         "CN=CA,O=mbed TLS,C=UK"
108 #define DFL_NOT_BEFORE          "20010101000000"
109 #define DFL_NOT_AFTER           "20301231235959"
110 #define DFL_SERIAL              "1"
111 #define DFL_SELFSIGN            0
112 #define DFL_IS_CA               0
113 #define DFL_MAX_PATHLEN         -1
114 #define DFL_KEY_USAGE           0
115 #define DFL_NS_CERT_TYPE        0
116 #define DFL_VERSION             3
117 #define DFL_AUTH_IDENT          1
118 #define DFL_SUBJ_IDENT          1
119 #define DFL_CONSTRAINTS         1
120 #define DFL_DIGEST              MBEDTLS_MD_SHA256
121 
122 #define USAGE \
123     "\n usage: cert_write param=<>...\n"                \
124     "\n acceptable parameters:\n"                       \
125     USAGE_CSR                                           \
126     "    subject_key=%%s          default: subject.key\n"   \
127     "    subject_pwd=%%s          default: (empty)\n"       \
128     "    subject_name=%%s         default: CN=Cert,O=mbed TLS,C=UK\n"   \
129     "\n"                                                \
130     "    issuer_crt=%%s           default: (empty)\n"       \
131     "                            If issuer_crt is specified, issuer_name is\n"  \
132     "                            ignored!\n"                \
133     "    issuer_name=%%s          default: CN=CA,O=mbed TLS,C=UK\n"     \
134     "\n"                                                \
135     "    selfsign=%%d             default: 0 (false)\n"     \
136     "                            If selfsign is enabled, issuer_name and\n" \
137     "                            issuer_key are required (issuer_crt and\n" \
138     "                            subject_* are ignored\n"   \
139     "    issuer_key=%%s           default: ca.key\n"        \
140     "    issuer_pwd=%%s           default: (empty)\n"       \
141     "    output_file=%%s          default: cert.crt\n"      \
142     "    serial=%%s               default: 1\n"             \
143     "    not_before=%%s           default: 20010101000000\n"\
144     "    not_after=%%s            default: 20301231235959\n"\
145     "    is_ca=%%d                default: 0 (disabled)\n"  \
146     "    max_pathlen=%%d          default: -1 (none)\n"     \
147     "    md=%%s                   default: SHA256\n"        \
148     "                            Supported values (if enabled):\n"      \
149     "                            MD2, MD4, MD5, RIPEMD160, SHA1,\n" \
150     "                            SHA224, SHA256, SHA384, SHA512\n" \
151     "    version=%%d              default: 3\n"            \
152     "                            Possible values: 1, 2, 3\n"\
153     "    subject_identifier=%%s   default: 1\n"             \
154     "                            Possible values: 0, 1\n"   \
155     "                            (Considered for v3 only)\n"\
156     "    authority_identifier=%%s default: 1\n"             \
157     "                            Possible values: 0, 1\n"   \
158     "                            (Considered for v3 only)\n"\
159     "    basic_constraints=%%d    default: 1\n"             \
160     "                            Possible values: 0, 1\n"   \
161     "                            (Considered for v3 only)\n"\
162     "    key_usage=%%s            default: (empty)\n"       \
163     "                            Comma-separated-list of values:\n"     \
164     "                            digital_signature\n"     \
165     "                            non_repudiation\n"       \
166     "                            key_encipherment\n"      \
167     "                            data_encipherment\n"     \
168     "                            key_agreement\n"         \
169     "                            key_cert_sign\n"  \
170     "                            crl_sign\n"              \
171     "                            (Considered for v3 only)\n"\
172     "    ns_cert_type=%%s         default: (empty)\n"       \
173     "                            Comma-separated-list of values:\n"     \
174     "                            ssl_client\n"            \
175     "                            ssl_server\n"            \
176     "                            email\n"                 \
177     "                            object_signing\n"        \
178     "                            ssl_ca\n"                \
179     "                            email_ca\n"              \
180     "                            object_signing_ca\n"     \
181     "\n"
182 
183 
184 /*
185  * global options
186  */
187 struct options
188 {
189     const char *issuer_crt;     /* filename of the issuer certificate   */
190     const char *request_file;   /* filename of the certificate request  */
191     const char *subject_key;    /* filename of the subject key file     */
192     const char *issuer_key;     /* filename of the issuer key file      */
193     const char *subject_pwd;    /* password for the subject key file    */
194     const char *issuer_pwd;     /* password for the issuer key file     */
195     const char *output_file;    /* where to store the constructed CRT   */
196     const char *subject_name;   /* subject name for certificate         */
197     const char *issuer_name;    /* issuer name for certificate          */
198     const char *not_before;     /* validity period not before           */
199     const char *not_after;      /* validity period not after            */
200     const char *serial;         /* serial number string                 */
201     int selfsign;               /* selfsign the certificate             */
202     int is_ca;                  /* is a CA certificate                  */
203     int max_pathlen;            /* maximum CA path length               */
204     int authority_identifier;   /* add authority identifier to CRT      */
205     int subject_identifier;     /* add subject identifier to CRT        */
206     int basic_constraints;      /* add basic constraints ext to CRT     */
207     int version;                /* CRT version                          */
208     mbedtls_md_type_t md;       /* Hash used for signing                */
209     unsigned char key_usage;    /* key usage flags                      */
210     unsigned char ns_cert_type; /* NS cert type                         */
211 } opt;
212 
write_certificate(mbedtls_x509write_cert * crt,const char * output_file,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)213 int write_certificate( mbedtls_x509write_cert *crt, const char *output_file,
214                        int (*f_rng)(void *, unsigned char *, size_t),
215                        void *p_rng )
216 {
217     int ret;
218     FILE *f;
219     unsigned char output_buf[4096];
220     size_t len = 0;
221 
222     memset( output_buf, 0, 4096 );
223     if( ( ret = mbedtls_x509write_crt_pem( crt, output_buf, 4096,
224                                            f_rng, p_rng ) ) < 0 )
225         return( ret );
226 
227     len = strlen( (char *) output_buf );
228 
229     if( ( f = fopen( output_file, "w" ) ) == NULL )
230         return( -1 );
231 
232     if( fwrite( output_buf, 1, len, f ) != len )
233     {
234         fclose( f );
235         return( -1 );
236     }
237 
238     fclose( f );
239 
240     return( 0 );
241 }
242 
main(int argc,char * argv[])243 int main( int argc, char *argv[] )
244 {
245     int ret = 1;
246     int exit_code = MBEDTLS_EXIT_FAILURE;
247     mbedtls_x509_crt issuer_crt;
248     mbedtls_pk_context loaded_issuer_key, loaded_subject_key;
249     mbedtls_pk_context *issuer_key = &loaded_issuer_key,
250                 *subject_key = &loaded_subject_key;
251     char buf[1024];
252     char issuer_name[256];
253     int i;
254     char *p, *q, *r;
255 #if defined(MBEDTLS_X509_CSR_PARSE_C)
256     char subject_name[256];
257     mbedtls_x509_csr csr;
258 #endif
259     mbedtls_x509write_cert crt;
260     mbedtls_mpi serial;
261     mbedtls_entropy_context entropy;
262     mbedtls_ctr_drbg_context ctr_drbg;
263     const char *pers = "crt example app";
264 
265     /*
266      * Set to sane values
267      */
268     mbedtls_x509write_crt_init( &crt );
269     mbedtls_pk_init( &loaded_issuer_key );
270     mbedtls_pk_init( &loaded_subject_key );
271     mbedtls_mpi_init( &serial );
272     mbedtls_ctr_drbg_init( &ctr_drbg );
273     mbedtls_entropy_init( &entropy );
274 #if defined(MBEDTLS_X509_CSR_PARSE_C)
275     mbedtls_x509_csr_init( &csr );
276 #endif
277     mbedtls_x509_crt_init( &issuer_crt );
278     memset( buf, 0, 1024 );
279 
280     if( argc == 0 )
281     {
282     usage:
283         mbedtls_printf( USAGE );
284         goto exit;
285     }
286 
287     opt.issuer_crt          = DFL_ISSUER_CRT;
288     opt.request_file        = DFL_REQUEST_FILE;
289     opt.subject_key         = DFL_SUBJECT_KEY;
290     opt.issuer_key          = DFL_ISSUER_KEY;
291     opt.subject_pwd         = DFL_SUBJECT_PWD;
292     opt.issuer_pwd          = DFL_ISSUER_PWD;
293     opt.output_file         = DFL_OUTPUT_FILENAME;
294     opt.subject_name        = DFL_SUBJECT_NAME;
295     opt.issuer_name         = DFL_ISSUER_NAME;
296     opt.not_before          = DFL_NOT_BEFORE;
297     opt.not_after           = DFL_NOT_AFTER;
298     opt.serial              = DFL_SERIAL;
299     opt.selfsign            = DFL_SELFSIGN;
300     opt.is_ca               = DFL_IS_CA;
301     opt.max_pathlen         = DFL_MAX_PATHLEN;
302     opt.key_usage           = DFL_KEY_USAGE;
303     opt.ns_cert_type        = DFL_NS_CERT_TYPE;
304     opt.version             = DFL_VERSION - 1;
305     opt.md                  = DFL_DIGEST;
306     opt.subject_identifier   = DFL_SUBJ_IDENT;
307     opt.authority_identifier = DFL_AUTH_IDENT;
308     opt.basic_constraints    = DFL_CONSTRAINTS;
309 
310     for( i = 1; i < argc; i++ )
311     {
312 
313         p = argv[i];
314         if( ( q = strchr( p, '=' ) ) == NULL )
315             goto usage;
316         *q++ = '\0';
317 
318         if( strcmp( p, "request_file" ) == 0 )
319             opt.request_file = q;
320         else if( strcmp( p, "subject_key" ) == 0 )
321             opt.subject_key = q;
322         else if( strcmp( p, "issuer_key" ) == 0 )
323             opt.issuer_key = q;
324         else if( strcmp( p, "subject_pwd" ) == 0 )
325             opt.subject_pwd = q;
326         else if( strcmp( p, "issuer_pwd" ) == 0 )
327             opt.issuer_pwd = q;
328         else if( strcmp( p, "issuer_crt" ) == 0 )
329             opt.issuer_crt = q;
330         else if( strcmp( p, "output_file" ) == 0 )
331             opt.output_file = q;
332         else if( strcmp( p, "subject_name" ) == 0 )
333         {
334             opt.subject_name = q;
335         }
336         else if( strcmp( p, "issuer_name" ) == 0 )
337         {
338             opt.issuer_name = q;
339         }
340         else if( strcmp( p, "not_before" ) == 0 )
341         {
342             opt.not_before = q;
343         }
344         else if( strcmp( p, "not_after" ) == 0 )
345         {
346             opt.not_after = q;
347         }
348         else if( strcmp( p, "serial" ) == 0 )
349         {
350             opt.serial = q;
351         }
352         else if( strcmp( p, "authority_identifier" ) == 0 )
353         {
354             opt.authority_identifier = atoi( q );
355             if( opt.authority_identifier != 0 &&
356                 opt.authority_identifier != 1 )
357             {
358                 mbedtls_printf( "Invalid argument for option %s\n", p );
359                 goto usage;
360             }
361         }
362         else if( strcmp( p, "subject_identifier" ) == 0 )
363         {
364             opt.subject_identifier = atoi( q );
365             if( opt.subject_identifier != 0 &&
366                 opt.subject_identifier != 1 )
367             {
368                 mbedtls_printf( "Invalid argument for option %s\n", p );
369                 goto usage;
370             }
371         }
372         else if( strcmp( p, "basic_constraints" ) == 0 )
373         {
374             opt.basic_constraints = atoi( q );
375             if( opt.basic_constraints != 0 &&
376                 opt.basic_constraints != 1 )
377             {
378                 mbedtls_printf( "Invalid argument for option %s\n", p );
379                 goto usage;
380             }
381         }
382         else if( strcmp( p, "md" ) == 0 )
383         {
384             const mbedtls_md_info_t *md_info =
385                 mbedtls_md_info_from_string( q );
386             if( md_info == NULL )
387             {
388                 mbedtls_printf( "Invalid argument for option %s\n", p );
389                 goto usage;
390             }
391             opt.md = mbedtls_md_get_type( md_info );
392         }
393         else if( strcmp( p, "version" ) == 0 )
394         {
395             opt.version = atoi( q );
396             if( opt.version < 1 || opt.version > 3 )
397             {
398                 mbedtls_printf( "Invalid argument for option %s\n", p );
399                 goto usage;
400             }
401             opt.version--;
402         }
403         else if( strcmp( p, "selfsign" ) == 0 )
404         {
405             opt.selfsign = atoi( q );
406             if( opt.selfsign < 0 || opt.selfsign > 1 )
407             {
408                 mbedtls_printf( "Invalid argument for option %s\n", p );
409                 goto usage;
410             }
411         }
412         else if( strcmp( p, "is_ca" ) == 0 )
413         {
414             opt.is_ca = atoi( q );
415             if( opt.is_ca < 0 || opt.is_ca > 1 )
416             {
417                 mbedtls_printf( "Invalid argument for option %s\n", p );
418                 goto usage;
419             }
420         }
421         else if( strcmp( p, "max_pathlen" ) == 0 )
422         {
423             opt.max_pathlen = atoi( q );
424             if( opt.max_pathlen < -1 || opt.max_pathlen > 127 )
425             {
426                 mbedtls_printf( "Invalid argument for option %s\n", p );
427                 goto usage;
428             }
429         }
430         else if( strcmp( p, "key_usage" ) == 0 )
431         {
432             while( q != NULL )
433             {
434                 if( ( r = strchr( q, ',' ) ) != NULL )
435                     *r++ = '\0';
436 
437                 if( strcmp( q, "digital_signature" ) == 0 )
438                     opt.key_usage |= MBEDTLS_X509_KU_DIGITAL_SIGNATURE;
439                 else if( strcmp( q, "non_repudiation" ) == 0 )
440                     opt.key_usage |= MBEDTLS_X509_KU_NON_REPUDIATION;
441                 else if( strcmp( q, "key_encipherment" ) == 0 )
442                     opt.key_usage |= MBEDTLS_X509_KU_KEY_ENCIPHERMENT;
443                 else if( strcmp( q, "data_encipherment" ) == 0 )
444                     opt.key_usage |= MBEDTLS_X509_KU_DATA_ENCIPHERMENT;
445                 else if( strcmp( q, "key_agreement" ) == 0 )
446                     opt.key_usage |= MBEDTLS_X509_KU_KEY_AGREEMENT;
447                 else if( strcmp( q, "key_cert_sign" ) == 0 )
448                     opt.key_usage |= MBEDTLS_X509_KU_KEY_CERT_SIGN;
449                 else if( strcmp( q, "crl_sign" ) == 0 )
450                     opt.key_usage |= MBEDTLS_X509_KU_CRL_SIGN;
451                 else
452                 {
453                     mbedtls_printf( "Invalid argument for option %s\n", p );
454                     goto usage;
455                 }
456 
457                 q = r;
458             }
459         }
460         else if( strcmp( p, "ns_cert_type" ) == 0 )
461         {
462             while( q != NULL )
463             {
464                 if( ( r = strchr( q, ',' ) ) != NULL )
465                     *r++ = '\0';
466 
467                 if( strcmp( q, "ssl_client" ) == 0 )
468                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT;
469                 else if( strcmp( q, "ssl_server" ) == 0 )
470                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER;
471                 else if( strcmp( q, "email" ) == 0 )
472                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_EMAIL;
473                 else if( strcmp( q, "object_signing" ) == 0 )
474                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_OBJECT_SIGNING;
475                 else if( strcmp( q, "ssl_ca" ) == 0 )
476                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_SSL_CA;
477                 else if( strcmp( q, "email_ca" ) == 0 )
478                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_EMAIL_CA;
479                 else if( strcmp( q, "object_signing_ca" ) == 0 )
480                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_OBJECT_SIGNING_CA;
481                 else
482                 {
483                     mbedtls_printf( "Invalid argument for option %s\n", p );
484                     goto usage;
485                 }
486 
487                 q = r;
488             }
489         }
490         else
491             goto usage;
492     }
493 
494     mbedtls_printf("\n");
495 
496     /*
497      * 0. Seed the PRNG
498      */
499     mbedtls_printf( "  . Seeding the random number generator..." );
500     fflush( stdout );
501 
502     if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
503                                (const unsigned char *) pers,
504                                strlen( pers ) ) ) != 0 )
505     {
506         mbedtls_strerror( ret, buf, 1024 );
507         mbedtls_printf( " failed\n  !  mbedtls_ctr_drbg_seed returned %d - %s\n",
508                         ret, buf );
509         goto exit;
510     }
511 
512     mbedtls_printf( " ok\n" );
513 
514     // Parse serial to MPI
515     //
516     mbedtls_printf( "  . Reading serial number..." );
517     fflush( stdout );
518 
519     if( ( ret = mbedtls_mpi_read_string( &serial, 10, opt.serial ) ) != 0 )
520     {
521         mbedtls_strerror( ret, buf, 1024 );
522         mbedtls_printf( " failed\n  !  mbedtls_mpi_read_string "
523                         "returned -0x%04x - %s\n\n", -ret, buf );
524         goto exit;
525     }
526 
527     mbedtls_printf( " ok\n" );
528 
529     // Parse issuer certificate if present
530     //
531     if( !opt.selfsign && strlen( opt.issuer_crt ) )
532     {
533         /*
534          * 1.0.a. Load the certificates
535          */
536         mbedtls_printf( "  . Loading the issuer certificate ..." );
537         fflush( stdout );
538 
539         if( ( ret = mbedtls_x509_crt_parse_file( &issuer_crt, opt.issuer_crt ) ) != 0 )
540         {
541             mbedtls_strerror( ret, buf, 1024 );
542             mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse_file "
543                             "returned -0x%04x - %s\n\n", -ret, buf );
544             goto exit;
545         }
546 
547         ret = mbedtls_x509_dn_gets( issuer_name, sizeof(issuer_name),
548                                  &issuer_crt.subject );
549         if( ret < 0 )
550         {
551             mbedtls_strerror( ret, buf, 1024 );
552             mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets "
553                             "returned -0x%04x - %s\n\n", -ret, buf );
554             goto exit;
555         }
556 
557         opt.issuer_name = issuer_name;
558 
559         mbedtls_printf( " ok\n" );
560     }
561 
562 #if defined(MBEDTLS_X509_CSR_PARSE_C)
563     // Parse certificate request if present
564     //
565     if( !opt.selfsign && strlen( opt.request_file ) )
566     {
567         /*
568          * 1.0.b. Load the CSR
569          */
570         mbedtls_printf( "  . Loading the certificate request ..." );
571         fflush( stdout );
572 
573         if( ( ret = mbedtls_x509_csr_parse_file( &csr, opt.request_file ) ) != 0 )
574         {
575             mbedtls_strerror( ret, buf, 1024 );
576             mbedtls_printf( " failed\n  !  mbedtls_x509_csr_parse_file "
577                             "returned -0x%04x - %s\n\n", -ret, buf );
578             goto exit;
579         }
580 
581         ret = mbedtls_x509_dn_gets( subject_name, sizeof(subject_name),
582                                  &csr.subject );
583         if( ret < 0 )
584         {
585             mbedtls_strerror( ret, buf, 1024 );
586             mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets "
587                             "returned -0x%04x - %s\n\n", -ret, buf );
588             goto exit;
589         }
590 
591         opt.subject_name = subject_name;
592         subject_key = &csr.pk;
593 
594         mbedtls_printf( " ok\n" );
595     }
596 #endif /* MBEDTLS_X509_CSR_PARSE_C */
597 
598     /*
599      * 1.1. Load the keys
600      */
601     if( !opt.selfsign && !strlen( opt.request_file ) )
602     {
603         mbedtls_printf( "  . Loading the subject key ..." );
604         fflush( stdout );
605 
606         ret = mbedtls_pk_parse_keyfile( &loaded_subject_key, opt.subject_key,
607                                  opt.subject_pwd );
608         if( ret != 0 )
609         {
610             mbedtls_strerror( ret, buf, 1024 );
611             mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile "
612                             "returned -0x%04x - %s\n\n", -ret, buf );
613             goto exit;
614         }
615 
616         mbedtls_printf( " ok\n" );
617     }
618 
619     mbedtls_printf( "  . Loading the issuer key ..." );
620     fflush( stdout );
621 
622     ret = mbedtls_pk_parse_keyfile( &loaded_issuer_key, opt.issuer_key,
623                              opt.issuer_pwd );
624     if( ret != 0 )
625     {
626         mbedtls_strerror( ret, buf, 1024 );
627         mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile "
628                         "returned -x%02x - %s\n\n", -ret, buf );
629         goto exit;
630     }
631 
632     // Check if key and issuer certificate match
633     //
634     if( strlen( opt.issuer_crt ) )
635     {
636         if( mbedtls_pk_check_pair( &issuer_crt.pk, issuer_key ) != 0 )
637         {
638             mbedtls_printf( " failed\n  !  issuer_key does not match "
639                             "issuer certificate\n\n" );
640             goto exit;
641         }
642     }
643 
644     mbedtls_printf( " ok\n" );
645 
646     if( opt.selfsign )
647     {
648         opt.subject_name = opt.issuer_name;
649         subject_key = issuer_key;
650     }
651 
652     mbedtls_x509write_crt_set_subject_key( &crt, subject_key );
653     mbedtls_x509write_crt_set_issuer_key( &crt, issuer_key );
654 
655     /*
656      * 1.0. Check the names for validity
657      */
658     if( ( ret = mbedtls_x509write_crt_set_subject_name( &crt, opt.subject_name ) ) != 0 )
659     {
660         mbedtls_strerror( ret, buf, 1024 );
661         mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject_name "
662                         "returned -0x%04x - %s\n\n", -ret, buf );
663         goto exit;
664     }
665 
666     if( ( ret = mbedtls_x509write_crt_set_issuer_name( &crt, opt.issuer_name ) ) != 0 )
667     {
668         mbedtls_strerror( ret, buf, 1024 );
669         mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_issuer_name "
670                         "returned -0x%04x - %s\n\n", -ret, buf );
671         goto exit;
672     }
673 
674     mbedtls_printf( "  . Setting certificate values ..." );
675     fflush( stdout );
676 
677     mbedtls_x509write_crt_set_version( &crt, opt.version );
678     mbedtls_x509write_crt_set_md_alg( &crt, opt.md );
679 
680     ret = mbedtls_x509write_crt_set_serial( &crt, &serial );
681     if( ret != 0 )
682     {
683         mbedtls_strerror( ret, buf, 1024 );
684         mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_serial "
685                         "returned -0x%04x - %s\n\n", -ret, buf );
686         goto exit;
687     }
688 
689     ret = mbedtls_x509write_crt_set_validity( &crt, opt.not_before, opt.not_after );
690     if( ret != 0 )
691     {
692         mbedtls_strerror( ret, buf, 1024 );
693         mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_validity "
694                         "returned -0x%04x - %s\n\n", -ret, buf );
695         goto exit;
696     }
697 
698     mbedtls_printf( " ok\n" );
699 
700     if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
701         opt.basic_constraints != 0 )
702     {
703         mbedtls_printf( "  . Adding the Basic Constraints extension ..." );
704         fflush( stdout );
705 
706         ret = mbedtls_x509write_crt_set_basic_constraints( &crt, opt.is_ca,
707                                                            opt.max_pathlen );
708         if( ret != 0 )
709         {
710             mbedtls_strerror( ret, buf, 1024 );
711             mbedtls_printf( " failed\n  !  x509write_crt_set_basic_contraints "
712                             "returned -0x%04x - %s\n\n", -ret, buf );
713             goto exit;
714         }
715 
716         mbedtls_printf( " ok\n" );
717     }
718 
719 #if defined(MBEDTLS_SHA1_C)
720     if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
721         opt.subject_identifier != 0 )
722     {
723         mbedtls_printf( "  . Adding the Subject Key Identifier ..." );
724         fflush( stdout );
725 
726         ret = mbedtls_x509write_crt_set_subject_key_identifier( &crt );
727         if( ret != 0 )
728         {
729             mbedtls_strerror( ret, buf, 1024 );
730             mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject"
731                             "_key_identifier returned -0x%04x - %s\n\n",
732                             -ret, buf );
733             goto exit;
734         }
735 
736         mbedtls_printf( " ok\n" );
737     }
738 
739     if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
740         opt.authority_identifier != 0 )
741     {
742         mbedtls_printf( "  . Adding the Authority Key Identifier ..." );
743         fflush( stdout );
744 
745         ret = mbedtls_x509write_crt_set_authority_key_identifier( &crt );
746         if( ret != 0 )
747         {
748             mbedtls_strerror( ret, buf, 1024 );
749             mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_authority_"
750                             "key_identifier returned -0x%04x - %s\n\n",
751                             -ret, buf );
752             goto exit;
753         }
754 
755         mbedtls_printf( " ok\n" );
756     }
757 #endif /* MBEDTLS_SHA1_C */
758 
759     if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
760         opt.key_usage != 0 )
761     {
762         mbedtls_printf( "  . Adding the Key Usage extension ..." );
763         fflush( stdout );
764 
765         ret = mbedtls_x509write_crt_set_key_usage( &crt, opt.key_usage );
766         if( ret != 0 )
767         {
768             mbedtls_strerror( ret, buf, 1024 );
769             mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_key_usage "
770                             "returned -0x%04x - %s\n\n", -ret, buf );
771             goto exit;
772         }
773 
774         mbedtls_printf( " ok\n" );
775     }
776 
777     if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
778         opt.ns_cert_type != 0 )
779     {
780         mbedtls_printf( "  . Adding the NS Cert Type extension ..." );
781         fflush( stdout );
782 
783         ret = mbedtls_x509write_crt_set_ns_cert_type( &crt, opt.ns_cert_type );
784         if( ret != 0 )
785         {
786             mbedtls_strerror( ret, buf, 1024 );
787             mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_ns_cert_type "
788                             "returned -0x%04x - %s\n\n", -ret, buf );
789             goto exit;
790         }
791 
792         mbedtls_printf( " ok\n" );
793     }
794 
795     /*
796      * 1.2. Writing the certificate
797      */
798     mbedtls_printf( "  . Writing the certificate..." );
799     fflush( stdout );
800 
801     if( ( ret = write_certificate( &crt, opt.output_file,
802                                    mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
803     {
804         mbedtls_strerror( ret, buf, 1024 );
805         mbedtls_printf( " failed\n  !  write_certificate -0x%04x - %s\n\n",
806                         -ret, buf );
807         goto exit;
808     }
809 
810     mbedtls_printf( " ok\n" );
811 
812     exit_code = MBEDTLS_EXIT_SUCCESS;
813 
814 exit:
815 #if defined(MBEDTLS_X509_CSR_PARSE_C)
816     mbedtls_x509_csr_free( &csr );
817 #endif /* MBEDTLS_X509_CSR_PARSE_C */
818     mbedtls_x509_crt_free( &issuer_crt );
819     mbedtls_x509write_crt_free( &crt );
820     mbedtls_pk_free( &loaded_subject_key );
821     mbedtls_pk_free( &loaded_issuer_key );
822     mbedtls_mpi_free( &serial );
823     mbedtls_ctr_drbg_free( &ctr_drbg );
824     mbedtls_entropy_free( &entropy );
825 
826 #if defined(_WIN32)
827     mbedtls_printf( "  + Press Enter to exit this program.\n" );
828     fflush( stdout ); getchar();
829 #endif
830 
831     mbedtls_exit( exit_code );
832 }
833 #endif /* MBEDTLS_X509_CRT_WRITE_C && MBEDTLS_X509_CRT_PARSE_C &&
834           MBEDTLS_FS_IO && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
835           MBEDTLS_ERROR_C && MBEDTLS_PEM_WRITE_C */
836