view libtomcrypt/src/pk/asn1/der/ia5/der_encode_ia5_string.c @ 1638:315fcba6960e

dropbearconvert: keyimport.c: fix BER encoding of secp521r1 keys (#69) keysizes >= 128 octets will be encoded with a 3 byte header which must be accounted by the optional-header Reproduce: master:~/build/dropbear$ ./dropbearkey -t ecdsa -s 521 -f K Generating 521 bit ecdsa key, this may take a while... master:~/build/dropbear$ ./dropbearconvert d o K L Key is a ecdsa-sha2-nistp521 key Wrote key to 'L' master:~/build/dropbear$ openssl ec < L read EC key unable to load Key 139769806448384:error:0D07209B:asn1 encoding routines:ASN1_get_object:too long:crypto/asn1/asn1_lib.c:91:
author Christian Hohnstädt <christian@hohnstaedt.de>
date Wed, 20 Mar 2019 16:42:47 +0100
parents 6dba84798cd5
children
line wrap: on
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */
#include "tomcrypt.h"

/**
  @file der_encode_ia5_string.c
  ASN.1 DER, encode a IA5 STRING, Tom St Denis
*/

#ifdef LTC_DER

/**
  Store an IA5 STRING
  @param in       The array of IA5 to store (one per char)
  @param inlen    The number of IA5 to store
  @param out      [out] The destination for the DER encoded IA5 STRING
  @param outlen   [in/out] The max size and resulting size of the DER IA5 STRING
  @return CRYPT_OK if successful
*/
int der_encode_ia5_string(const unsigned char *in, unsigned long inlen,
                                unsigned char *out, unsigned long *outlen)
{
   unsigned long x, y, len;
   int           err;

   LTC_ARGCHK(in     != NULL);
   LTC_ARGCHK(out    != NULL);
   LTC_ARGCHK(outlen != NULL);

   /* get the size */
   if ((err = der_length_ia5_string(in, inlen, &len)) != CRYPT_OK) {
      return err;
   }

   /* too big? */
   if (len > *outlen) {
      *outlen = len;
      return CRYPT_BUFFER_OVERFLOW;
   }

   /* encode the header+len */
   x = 0;
   out[x++] = 0x16;
   if (inlen < 128) {
      out[x++] = (unsigned char)inlen;
   } else if (inlen < 256) {
      out[x++] = 0x81;
      out[x++] = (unsigned char)inlen;
   } else if (inlen < 65536UL) {
      out[x++] = 0x82;
      out[x++] = (unsigned char)((inlen>>8)&255);
      out[x++] = (unsigned char)(inlen&255);
   } else if (inlen < 16777216UL) {
      out[x++] = 0x83;
      out[x++] = (unsigned char)((inlen>>16)&255);
      out[x++] = (unsigned char)((inlen>>8)&255);
      out[x++] = (unsigned char)(inlen&255);
   } else {
      return CRYPT_INVALID_ARG;
   }

   /* store octets */
   for (y = 0; y < inlen; y++) {
       out[x++] = der_ia5_char_encode(in[y]);
   }

   /* retun length */
   *outlen = x;

   return CRYPT_OK;
}

#endif

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