_ Git - BearSSL/blob - src/x509/encode_rsa_rawder.c

   1 /*
   2  * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include "inner.h"
  26
  27 /* see bearssl_x509.h */
  28 size_t
  29 br_encode_rsa_raw_der(void *dest, const br_rsa_private_key *sk,
  30         const br_rsa_public_key *pk, const void *d, size_t dlen)
  31 {
  32         /*
  33          * ASN.1 format:
  34          *
  35          *   RSAPrivateKey ::= SEQUENCE {
  36          *       version           Version,
  37          *       modulus           INTEGER,  -- n
  38          *       publicExponent    INTEGER,  -- e
  39          *       privateExponent   INTEGER,  -- d
  40          *       prime1            INTEGER,  -- p
  41          *       prime2            INTEGER,  -- q
  42          *       exponent1         INTEGER,  -- d mod (p-1)
  43          *       exponent2         INTEGER,  -- d mod (q-1)
  44          *       coefficient       INTEGER,  -- (inverse of q) mod p
  45          *       otherPrimeInfos   OtherPrimeInfos OPTIONAL
  46          *   }
  47          *
  48          * The 'version' field is an INTEGER of value 0 (meaning: there
  49          * are exactly two prime factors), and 'otherPrimeInfos' will
  50          * be absent (because there are exactly two prime factors).
  51          */
  52
  53         br_asn1_uint num[9];
  54         size_t u, slen;
  55
  56         /*
  57          * For all INTEGER values, get the pointer and length for the
  58          * data bytes.
  59          */
  60         num[0] = br_asn1_uint_prepare(NULL, 0);
  61         num[1] = br_asn1_uint_prepare(pk->n, pk->nlen);
  62         num[2] = br_asn1_uint_prepare(pk->e, pk->elen);
  63         num[3] = br_asn1_uint_prepare(d, dlen);
  64         num[4] = br_asn1_uint_prepare(sk->p, sk->plen);
  65         num[5] = br_asn1_uint_prepare(sk->q, sk->qlen);
  66         num[6] = br_asn1_uint_prepare(sk->dp, sk->dplen);
  67         num[7] = br_asn1_uint_prepare(sk->dq, sk->dqlen);
  68         num[8] = br_asn1_uint_prepare(sk->iq, sk->iqlen);
  69
  70         /*
  71          * Get the length of the SEQUENCE contents.
  72          */
  73         slen = 0;
  74         for (u = 0; u < 9; u ++) {
  75                 uint32_t ilen;
  76
  77                 ilen = num[u].asn1len;
  78                 slen += 1 + len_of_len(ilen) + ilen;
  79         }
  80
  81         if (dest == NULL) {
  82                 return 1 + len_of_len(slen) + slen;
  83         } else {
  84                 unsigned char *buf;
  85                 size_t lenlen;
  86
  87                 buf = dest;
  88                 *buf ++ = 0x30;  /* SEQUENCE tag */
  89                 lenlen = br_asn1_encode_length(buf, slen);
  90                 buf += lenlen;
  91                 for (u = 0; u < 9; u ++) {
  92                         buf += br_asn1_encode_uint(buf, num[u]);
  93                 }
  94                 return 1 + lenlen + slen;
  95         }
  96 }