common/mbedtls/x509_create.c

   1 /*
   2  *  X.509 base functions for creating certificates / CSRs
   3  *
   4  *  Copyright The Mbed TLS Contributors
   5  *  SPDX-License-Identifier: Apache-2.0
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   8  *  not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *  http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  15  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License.
  18  */
  19
  20 #include "common.h"
  21
  22 #if defined(MBEDTLS_X509_CREATE_C)
  23
  24 #include "mbedtls/x509.h"
  25 #include "mbedtls/asn1write.h"
  26 #include "mbedtls/error.h"
  27 #include "mbedtls/oid.h"
  28
  29 #include <string.h>
  30
  31 /* Structure linking OIDs for X.509 DN AttributeTypes to their
  32  * string representations and default string encodings used by Mbed TLS. */
  33 typedef struct {
  34     const char *name; /* String representation of AttributeType, e.g.
  35                       * "CN" or "emailAddress". */
  36     size_t name_len;  /* Length of 'name', without trailing 0 byte. */
  37     const char *oid;  /* String representation of OID of AttributeType,
  38                       * as per RFC 5280, Appendix A.1. */
  39     int default_tag;  /* The default character encoding used for the
  40                       * given attribute type, e.g.
  41                       * MBEDTLS_ASN1_UTF8_STRING for UTF-8. */
  42 } x509_attr_descriptor_t;
  43
  44 #define ADD_STRLEN( s )     s, sizeof( s ) - 1
  45
  46 /* X.509 DN attributes from RFC 5280, Appendix A.1. */
  47 static const x509_attr_descriptor_t x509_attrs[] = {
  48     {
  49         ADD_STRLEN("CN"),
  50         MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING
  51     },
  52     {
  53         ADD_STRLEN("commonName"),
  54         MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING
  55     },
  56     {
  57         ADD_STRLEN("C"),
  58         MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING
  59     },
  60     {
  61         ADD_STRLEN("countryName"),
  62         MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING
  63     },
  64     {
  65         ADD_STRLEN("O"),
  66         MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING
  67     },
  68     {
  69         ADD_STRLEN("organizationName"),
  70         MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING
  71     },
  72     {
  73         ADD_STRLEN("L"),
  74         MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING
  75     },
  76     {
  77         ADD_STRLEN("locality"),
  78         MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING
  79     },
  80     {
  81         ADD_STRLEN("R"),
  82         MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING
  83     },
  84     {
  85         ADD_STRLEN("OU"),
  86         MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING
  87     },
  88     {
  89         ADD_STRLEN("organizationalUnitName"),
  90         MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING
  91     },
  92     {
  93         ADD_STRLEN("ST"),
  94         MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING
  95     },
  96     {
  97         ADD_STRLEN("stateOrProvinceName"),
  98         MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING
  99     },
 100     {
 101         ADD_STRLEN("emailAddress"),
 102         MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING
 103     },
 104     {
 105         ADD_STRLEN("serialNumber"),
 106         MBEDTLS_OID_AT_SERIAL_NUMBER, MBEDTLS_ASN1_PRINTABLE_STRING
 107     },
 108     {
 109         ADD_STRLEN("postalAddress"),
 110         MBEDTLS_OID_AT_POSTAL_ADDRESS, MBEDTLS_ASN1_PRINTABLE_STRING
 111     },
 112     {
 113         ADD_STRLEN("postalCode"),
 114         MBEDTLS_OID_AT_POSTAL_CODE, MBEDTLS_ASN1_PRINTABLE_STRING
 115     },
 116     {
 117         ADD_STRLEN("dnQualifier"),
 118         MBEDTLS_OID_AT_DN_QUALIFIER, MBEDTLS_ASN1_PRINTABLE_STRING
 119     },
 120     {
 121         ADD_STRLEN("title"),
 122         MBEDTLS_OID_AT_TITLE, MBEDTLS_ASN1_UTF8_STRING
 123     },
 124     {
 125         ADD_STRLEN("surName"),
 126         MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING
 127     },
 128     {
 129         ADD_STRLEN("SN"),
 130         MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING
 131     },
 132     {
 133         ADD_STRLEN("givenName"),
 134         MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING
 135     },
 136     {
 137         ADD_STRLEN("GN"),
 138         MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING
 139     },
 140     {
 141         ADD_STRLEN("initials"),
 142         MBEDTLS_OID_AT_INITIALS, MBEDTLS_ASN1_UTF8_STRING
 143     },
 144     {
 145         ADD_STRLEN("pseudonym"),
 146         MBEDTLS_OID_AT_PSEUDONYM, MBEDTLS_ASN1_UTF8_STRING
 147     },
 148     {
 149         ADD_STRLEN("generationQualifier"),
 150         MBEDTLS_OID_AT_GENERATION_QUALIFIER, MBEDTLS_ASN1_UTF8_STRING
 151     },
 152     {
 153         ADD_STRLEN("domainComponent"),
 154         MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING
 155     },
 156     {
 157         ADD_STRLEN("DC"),
 158         MBEDTLS_OID_DOMAIN_COMPONENT,   MBEDTLS_ASN1_IA5_STRING
 159     },
 160     { NULL, 0, NULL, MBEDTLS_ASN1_NULL }
 161 };
 162
 163 static const x509_attr_descriptor_t *x509_attr_descr_from_name(const char *name, size_t name_len) {
 164     const x509_attr_descriptor_t *cur;
 165
 166     for (cur = x509_attrs; cur->name != NULL; cur++)
 167         if (cur->name_len == name_len &&
 168                 strncmp(cur->name, name, name_len) == 0)
 169             break;
 170
 171     if (cur->name == NULL)
 172         return (NULL);
 173
 174     return (cur);
 175 }
 176
 177 int mbedtls_x509_string_to_names(mbedtls_asn1_named_data **head, const char *name) {
 178     int ret = 0;
 179     const char *s = name, *c = s;
 180     const char *end = s + strlen(s);
 181     const char *oid = NULL;
 182     const x509_attr_descriptor_t *attr_descr = NULL;
 183     int in_tag = 1;
 184     char data[MBEDTLS_X509_MAX_DN_NAME_SIZE];
 185     char *d = data;
 186
 187     /* Clear existing chain if present */
 188     mbedtls_asn1_free_named_data_list(head);
 189
 190     while (c <= end) {
 191         if (in_tag && *c == '=') {
 192             if ((attr_descr = x509_attr_descr_from_name(s, c - s)) == NULL) {
 193                 ret = MBEDTLS_ERR_X509_UNKNOWN_OID;
 194                 goto exit;
 195             }
 196
 197             oid = attr_descr->oid;
 198             s = c + 1;
 199             in_tag = 0;
 200             d = data;
 201         }
 202
 203         if (!in_tag && *c == '\\' && c != end) {
 204             c++;
 205
 206             /* Check for valid escaped characters */
 207             if (c == end || *c != ',') {
 208                 ret = MBEDTLS_ERR_X509_INVALID_NAME;
 209                 goto exit;
 210             }
 211         } else if (!in_tag && (*c == ',' || c == end)) {
 212             mbedtls_asn1_named_data *cur =
 213                 mbedtls_asn1_store_named_data(head, oid, strlen(oid),
 214                                               (unsigned char *) data,
 215                                               d - data);
 216
 217             if (cur == NULL) {
 218                 return (MBEDTLS_ERR_X509_ALLOC_FAILED);
 219             }
 220
 221             // set tagType
 222             cur->val.tag = attr_descr->default_tag;
 223
 224             while (c < end && *(c + 1) == ' ')
 225                 c++;
 226
 227             s = c + 1;
 228             in_tag = 1;
 229         }
 230
 231         if (!in_tag && s != c + 1) {
 232             *(d++) = *c;
 233
 234             if (d - data == MBEDTLS_X509_MAX_DN_NAME_SIZE) {
 235                 ret = MBEDTLS_ERR_X509_INVALID_NAME;
 236                 goto exit;
 237             }
 238         }
 239
 240         c++;
 241     }
 242
 243 exit:
 244
 245     return (ret);
 246 }
 247
 248 /* The first byte of the value in the mbedtls_asn1_named_data structure is reserved
 249  * to store the critical boolean for us
 250  */
 251 int mbedtls_x509_set_extension(mbedtls_asn1_named_data **head, const char *oid, size_t oid_len,
 252                                int critical, const unsigned char *val, size_t val_len) {
 253     mbedtls_asn1_named_data *cur;
 254
 255     if ((cur = mbedtls_asn1_store_named_data(head, oid, oid_len,
 256                                              NULL, val_len + 1)) == NULL) {
 257         return (MBEDTLS_ERR_X509_ALLOC_FAILED);
 258     }
 259
 260     cur->val.p[0] = critical;
 261     memcpy(cur->val.p + 1, val, val_len);
 262
 263     return (0);
 264 }
 265
 266 /*
 267  *  RelativeDistinguishedName ::=
 268  *    SET OF AttributeTypeAndValue
 269  *
 270  *  AttributeTypeAndValue ::= SEQUENCE {
 271  *    type     AttributeType,
 272  *    value    AttributeValue }
 273  *
 274  *  AttributeType ::= OBJECT IDENTIFIER
 275  *
 276  *  AttributeValue ::= ANY DEFINED BY AttributeType
 277  */
 278 static int x509_write_name(unsigned char **p, unsigned char *start, mbedtls_asn1_named_data *cur_name) {
 279     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 280     size_t len = 0;
 281     const char *oid             = (const char *)cur_name->oid.p;
 282     size_t oid_len              = cur_name->oid.len;
 283     const unsigned char *name   = cur_name->val.p;
 284     size_t name_len             = cur_name->val.len;
 285
 286     // Write correct string tag and value
 287     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tagged_string(p, start,
 288                                                                cur_name->val.tag,
 289                                                                (const char *) name,
 290                                                                name_len));
 291     // Write OID
 292     //
 293     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid,
 294                                                      oid_len));
 295
 296     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
 297     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
 298                                                      MBEDTLS_ASN1_CONSTRUCTED |
 299                                                      MBEDTLS_ASN1_SEQUENCE));
 300
 301     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
 302     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
 303                                                      MBEDTLS_ASN1_CONSTRUCTED |
 304                                                      MBEDTLS_ASN1_SET));
 305
 306     return ((int) len);
 307 }
 308
 309 int mbedtls_x509_write_names(unsigned char **p, unsigned char *start,
 310                              mbedtls_asn1_named_data *first) {
 311     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 312     size_t len = 0;
 313     mbedtls_asn1_named_data *cur = first;
 314
 315     while (cur != NULL) {
 316         MBEDTLS_ASN1_CHK_ADD(len, x509_write_name(p, start, cur));
 317         cur = cur->next;
 318     }
 319
 320     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
 321     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
 322                                                      MBEDTLS_ASN1_SEQUENCE));
 323
 324     return ((int) len);
 325 }
 326
 327 int mbedtls_x509_write_sig(unsigned char **p, unsigned char *start,
 328                            const char *oid, size_t oid_len,
 329                            unsigned char *sig, size_t size) {
 330     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 331     size_t len = 0;
 332
 333     if (*p < start || (size_t)(*p - start) < size)
 334         return (MBEDTLS_ERR_ASN1_BUF_TOO_SMALL);
 335
 336     len = size;
 337     (*p) -= len;
 338     memcpy(*p, sig, len);
 339
 340     if (*p - start < 1)
 341         return (MBEDTLS_ERR_ASN1_BUF_TOO_SMALL);
 342
 343     *--(*p) = 0;
 344     len += 1;
 345
 346     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
 347     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING));
 348
 349     // Write OID
 350     //
 351     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(p, start, oid,
 352                          oid_len, 0));
 353
 354     return ((int) len);
 355 }
 356
 357 static int x509_write_extension(unsigned char **p, unsigned char *start,
 358                                 mbedtls_asn1_named_data *ext) {
 359     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 360     size_t len = 0;
 361
 362     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->val.p + 1,
 363                                                             ext->val.len - 1));
 364     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->val.len - 1));
 365     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING));
 366
 367     if (ext->val.p[0] != 0) {
 368         MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_bool(p, start, 1));
 369     }
 370
 371     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->oid.p,
 372                                                             ext->oid.len));
 373     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->oid.len));
 374     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID));
 375
 376     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
 377     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
 378                                                      MBEDTLS_ASN1_SEQUENCE));
 379
 380     return ((int) len);
 381 }
 382
 383 /*
 384  * Extension  ::=  SEQUENCE  {
 385  *     extnID      OBJECT IDENTIFIER,
 386  *     critical    BOOLEAN DEFAULT FALSE,
 387  *     extnValue   OCTET STRING
 388  *                 -- contains the DER encoding of an ASN.1 value
 389  *                 -- corresponding to the extension type identified
 390  *                 -- by extnID
 391  *     }
 392  */
 393 int mbedtls_x509_write_extensions(unsigned char **p, unsigned char *start,
 394                                   mbedtls_asn1_named_data *first) {
 395     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 396     size_t len = 0;
 397     mbedtls_asn1_named_data *cur_ext = first;
 398
 399     while (cur_ext != NULL) {
 400         MBEDTLS_ASN1_CHK_ADD(len, x509_write_extension(p, start, cur_ext));
 401         cur_ext = cur_ext->next;
 402     }
 403
 404     return ((int) len);
 405 }
 406
 407 #endif /* MBEDTLS_X509_CREATE_C */