text: /*
   *  X.509 certificate writing
   *
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  /*
   * References:
   * - certificates: RFC 5280, updated by RFC 6818
   * - CSRs: PKCS#10 v1.7 aka RFC 2986
   * - attributes: PKCS#9 v2.0 aka RFC 2985
   */
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "mbedtls/config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if defined(MBEDTLS_X509_CRT_WRITE_C)
  
  #include "mbedtls/x509_crt.h"
  #include "mbedtls/oid.h"
  #include "mbedtls/asn1write.h"
  #include "mbedtls/sha1.h"
  
  #include <string.h>
  
  #if defined(MBEDTLS_PEM_WRITE_C)
  #include "mbedtls/pem.h"
  #endif /* MBEDTLS_PEM_WRITE_C */
  
  /* Implementation that should never be optimized out by the compiler */
  static void mbedtls_zeroize( void *v, size_t n ) {
      volatile unsigned char *p = v; while( n-- ) *p++ = 0;
  }
  
  void mbedtls_x509write_crt_init( mbedtls_x509write_cert *ctx )
  {
      memset( ctx, 0, sizeof(mbedtls_x509write_cert) );
  
      mbedtls_mpi_init( &ctx->serial );
      ctx->version = MBEDTLS_X509_CRT_VERSION_3;
  }
  
  void mbedtls_x509write_crt_free( mbedtls_x509write_cert *ctx )
  {
      mbedtls_mpi_free( &ctx->serial );
  
      mbedtls_asn1_free_named_data_list( &ctx->subject );
      mbedtls_asn1_free_named_data_list( &ctx->issuer );
      mbedtls_asn1_free_named_data_list( &ctx->extensions );
  
      mbedtls_zeroize( ctx, sizeof(mbedtls_x509write_cert) );
  }
  
  void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx, int version )
  {
      ctx->version = version;
  }
  
  void mbedtls_x509write_crt_set_md_alg( mbedtls_x509write_cert *ctx, mbedtls_md_type_t md_alg )
  {
      ctx->md_alg = md_alg;
  }
  
  void mbedtls_x509write_crt_set_subject_key( mbedtls_x509write_cert *ctx, mbedtls_pk_context *key )
  {
      ctx->subject_key = key;
  }
  
  void mbedtls_x509write_crt_set_issuer_key( mbedtls_x509write_cert *ctx, mbedtls_pk_context *key )
  {
      ctx->issuer_key = key;
  }
  
  int mbedtls_x509write_crt_set_subject_name( mbedtls_x509write_cert *ctx,
                                      const char *subject_name )
  {
      return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
  }
  
  int mbedtls_x509write_crt_set_issuer_name( mbedtls_x509write_cert *ctx,
                                     const char *issuer_name )
  {
      return mbedtls_x509_string_to_names( &ctx->issuer, issuer_name );
  }
  
  int mbedtls_x509write_crt_set_serial( mbedtls_x509write_cert *ctx, const mbedtls_mpi *serial )
  {
      int ret;
  
      if( ( ret = mbedtls_mpi_copy( &ctx->serial, serial ) ) != 0 )
          return( ret );
  
      return( 0 );
  }
  
  int mbedtls_x509write_crt_set_validity( mbedtls_x509write_cert *ctx, const char *not_before,
                                  const char *not_after )
  {
      if( strlen( not_before ) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 ||
          strlen( not_after )  != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 )
      {
          return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
      }
      strncpy( ctx->not_before, not_before, MBEDTLS_X509_RFC5280_UTC_TIME_LEN );
      strncpy( ctx->not_after , not_after , MBEDTLS_X509_RFC5280_UTC_TIME_LEN );
      ctx->not_before[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
      ctx->not_after[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
  
      return( 0 );
  }
  
  int mbedtls_x509write_crt_set_extension( mbedtls_x509write_cert *ctx,
                                   const char *oid, size_t oid_len,
                                   int critical,
                                   const unsigned char *val, size_t val_len )
  {
      return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
                                 critical, val, val_len );
  }
  
  int mbedtls_x509write_crt_set_basic_constraints( mbedtls_x509write_cert *ctx,
                                           int is_ca, int max_pathlen )
  {
      int ret;
      unsigned char buf[9];
      unsigned char *c = buf + sizeof(buf);
      size_t len = 0;
  
      memset( buf, 0, sizeof(buf) );
  
      if( is_ca && max_pathlen > 127 )
          return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
  
      if( is_ca )
      {
          if( max_pathlen >= 0 )
          {
              MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, max_pathlen ) );
          }
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_bool( &c, buf, 1 ) );
      }
  
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                  MBEDTLS_ASN1_SEQUENCE ) );
  
      return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_BASIC_CONSTRAINTS,
                                          MBEDTLS_OID_SIZE( MBEDTLS_OID_BASIC_CONSTRAINTS ),
                                          0, buf + sizeof(buf) - len, len );
  }
  
  #if defined(MBEDTLS_SHA1_C)
  int mbedtls_x509write_crt_set_subject_key_identifier( mbedtls_x509write_cert *ctx )
  {
      int ret;
      unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
      unsigned char *c = buf + sizeof(buf);
      size_t len = 0;
  
      memset( buf, 0, sizeof(buf) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->subject_key ) );
  
      mbedtls_sha1( buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20 );
      c = buf + sizeof(buf) - 20;
      len = 20;
  
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_OCTET_STRING ) );
  
      return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER,
                                          MBEDTLS_OID_SIZE( MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER ),
                                          0, buf + sizeof(buf) - len, len );
  }
  
  int mbedtls_x509write_crt_set_authority_key_identifier( mbedtls_x509write_cert *ctx )
  {
      int ret;
      unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
      unsigned char *c = buf + sizeof(buf);
      size_t len = 0;
  
      memset( buf, 0, sizeof(buf) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
  
      mbedtls_sha1( buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20 );
      c = buf + sizeof(buf) - 20;
      len = 20;
  
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0 ) );
  
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                  MBEDTLS_ASN1_SEQUENCE ) );
  
      return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
                                     MBEDTLS_OID_SIZE( MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER ),
                                     0, buf + sizeof(buf) - len, len );
  }
  #endif /* MBEDTLS_SHA1_C */
  
  int mbedtls_x509write_crt_set_key_usage( mbedtls_x509write_cert *ctx,
                                           unsigned int key_usage )
  {
      unsigned char buf[4], ku;
      unsigned char *c;
      int ret;
  
      /* We currently only support 7 bits, from 0x80 to 0x02 */
      if( ( key_usage & ~0xfe ) != 0 )
          return( MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE );
  
      c = buf + 4;
      ku = (unsigned char) key_usage;
  
      if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ku, 7 ) ) != 4 )
          return( ret );
  
      ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
                                         MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
                                         1, buf, 4 );
      if( ret != 0 )
          return( ret );
  
      return( 0 );
  }
  
  int mbedtls_x509write_crt_set_ns_cert_type( mbedtls_x509write_cert *ctx,
                                      unsigned char ns_cert_type )
  {
      unsigned char buf[4];
      unsigned char *c;
      int ret;
  
      c = buf + 4;
  
      if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 )
          return( ret );
  
      ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
                                         MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
                                         0, buf, 4 );
      if( ret != 0 )
          return( ret );
  
      return( 0 );
  }
  
  static int x509_write_time( unsigned char **p, unsigned char *start,
                              const char *time, size_t size )
  {
      int ret;
      size_t len = 0;
  
      /*
       * write MBEDTLS_ASN1_UTC_TIME if year < 2050 (2 bytes shorter)
       */
      if( time[0] == '2' && time[1] == '0' && time [2] < '5' )
      {
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
                                               (const unsigned char *) time + 2,
                                               size - 2 ) );
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_UTC_TIME ) );
      }
      else
      {
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
                                                    (const unsigned char *) time,
                                                    size ) );
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
          MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_GENERALIZED_TIME ) );
      }
  
      return( (int) len );
  }
  
  int mbedtls_x509write_crt_der( mbedtls_x509write_cert *ctx, unsigned char *buf, size_t size,
                         int (*f_rng)(void *, unsigned char *, size_t),
                         void *p_rng )
  {
      int ret;
      const char *sig_oid;
      size_t sig_oid_len = 0;
      unsigned char *c, *c2;
      unsigned char hash[64];
      unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
      unsigned char tmp_buf[2048];
      size_t sub_len = 0, pub_len = 0, sig_and_oid_len = 0, sig_len;
      size_t len = 0;
      mbedtls_pk_type_t pk_alg;
  
      /*
       * Prepare data to be signed in tmp_buf
       */
      c = tmp_buf + sizeof( tmp_buf );
  
      /* Signature algorithm needed in TBS, and later for actual signature */
      pk_alg = mbedtls_pk_get_type( ctx->issuer_key );
      if( pk_alg == MBEDTLS_PK_ECKEY )
          pk_alg = MBEDTLS_PK_ECDSA;
  
      if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
                                          &sig_oid, &sig_oid_len ) ) != 0 )
      {
          return( ret );
      }
  
      /*
       *  Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
       */
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                      MBEDTLS_ASN1_SEQUENCE ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
                                                      MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
  
      /*
       *  SubjectPublicKeyInfo
       */
      MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->subject_key,
                                                  tmp_buf, c - tmp_buf ) );
      c -= pub_len;
      len += pub_len;
  
      /*
       *  Subject  ::=  Name
       */
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) );
  
      /*
       *  Validity ::= SEQUENCE {
       *       notBefore      Time,
       *       notAfter       Time }
       */
      sub_len = 0;
  
      MBEDTLS_ASN1_CHK_ADD( sub_len, x509_write_time( &c, tmp_buf, ctx->not_after,
                                              MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
  
      MBEDTLS_ASN1_CHK_ADD( sub_len, x509_write_time( &c, tmp_buf, ctx->not_before,
                                              MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
  
      len += sub_len;
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                      MBEDTLS_ASN1_SEQUENCE ) );
  
      /*
       *  Issuer  ::=  Name
       */
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->issuer ) );
  
      /*
       *  Signature   ::=  AlgorithmIdentifier
       */
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( &c, tmp_buf,
                         sig_oid, strlen( sig_oid ), 0 ) );
  
      /*
       *  Serial   ::=  INTEGER
       */
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, tmp_buf, &ctx->serial ) );
  
      /*
       *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
       */
      sub_len = 0;
      MBEDTLS_ASN1_CHK_ADD( sub_len, mbedtls_asn1_write_int( &c, tmp_buf, ctx->version ) );
      len += sub_len;
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
                                                      MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
  
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                      MBEDTLS_ASN1_SEQUENCE ) );
  
      /*
       * Make signature
       */
      mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
  
      if( ( ret = mbedtls_pk_sign( ctx->issuer_key, ctx->md_alg, hash, 0, sig, &sig_len,
                           f_rng, p_rng ) ) != 0 )
      {
          return( ret );
      }
  
      /*
       * Write data to output buffer
       */
      c2 = buf + size;
      MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf,
                                          sig_oid, sig_oid_len, sig, sig_len ) );
  
      if( len > (size_t)( c2 - buf ) )
          return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  
      c2 -= len;
      memcpy( c2, c, len );
  
      len += sig_and_oid_len;
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );
      MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED |
                                                   MBEDTLS_ASN1_SEQUENCE ) );
  
      return( (int) len );
  }
  
  #define PEM_BEGIN_CRT           "-----BEGIN CERTIFICATE-----\n"
  #define PEM_END_CRT             "-----END CERTIFICATE-----\n"
  
  #if defined(MBEDTLS_PEM_WRITE_C)
  int mbedtls_x509write_crt_pem( mbedtls_x509write_cert *crt, unsigned char *buf, size_t size,
                         int (*f_rng)(void *, unsigned char *, size_t),
                         void *p_rng )
  {
      int ret;
      unsigned char output_buf[4096];
      size_t olen = 0;
  
      if( ( ret = mbedtls_x509write_crt_der( crt, output_buf, sizeof(output_buf),
                                     f_rng, p_rng ) ) < 0 )
      {
          return( ret );
      }
  
      if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CRT, PEM_END_CRT,
                                    output_buf + sizeof(output_buf) - ret,
                                    ret, buf, size, &olen ) ) != 0 )
      {
          return( ret );
      }
  
      return( 0 );
  }
  #endif /* MBEDTLS_PEM_WRITE_C */
  
  #endif /* MBEDTLS_X509_CRT_WRITE_C */
  