view libtomcrypt/src/pk/katja/katja_export.c @ 1715:3974f087d9c0

Disallow leading lines before the ident for server (#102) Per RFC4253 4.2 clients must be able to process other lines of data before the version string, server behavior is not defined neither with MUST/SHOULD nor with MAY. If server process up to 50 lines too - it may cause too long hanging session with invalid/evil client that consume host resources and potentially may lead to DDoS on poor embedded boxes. Let's require first line from client to be version string and fail early if it's not - matches both RFC and real OpenSSH behavior.
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Mon, 15 Jun 2020 18:22:18 +0500
parents 6dba84798cd5
children
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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 katja_export.c
  Export Katja PKCS-style keys, Tom St Denis
*/

#ifdef LTC_MKAT

/**
    This will export either an KatjaPublicKey or KatjaPrivateKey
    @param out       [out] Destination of the packet
    @param outlen    [in/out] The max size and resulting size of the packet
    @param type      The type of exported key (PK_PRIVATE or PK_PUBLIC)
    @param key       The Katja key to export
    @return CRYPT_OK if successful
*/
int katja_export(unsigned char *out, unsigned long *outlen, int type, katja_key *key)
{
   int           err;
   unsigned long zero=0;

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

   /* type valid? */
   if (!(key->type == PK_PRIVATE) && (type == PK_PRIVATE)) {
      return CRYPT_PK_INVALID_TYPE;
   }

   if (type == PK_PRIVATE) {
      /* private key */
      /* output is
            Version, n, d, p, q, d mod (p-1), d mod (q - 1), 1/q mod p, pq
       */
      if ((err = der_encode_sequence_multi(out, outlen,
                          LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
                          LTC_ASN1_INTEGER, 1UL,  key->N,
                          LTC_ASN1_INTEGER, 1UL,  key->d,
                          LTC_ASN1_INTEGER, 1UL,  key->p,
                          LTC_ASN1_INTEGER, 1UL,  key->q,
                          LTC_ASN1_INTEGER, 1UL,  key->dP,
                          LTC_ASN1_INTEGER, 1UL,  key->dQ,
                          LTC_ASN1_INTEGER, 1UL,  key->qP,
                          LTC_ASN1_INTEGER, 1UL,  key->pq,
                          LTC_ASN1_EOL,     0UL, NULL)) != CRYPT_OK) {
         return err;
      }

      /* clear zero and return */
      return CRYPT_OK;
   } else {
      /* public key */
      return der_encode_sequence_multi(out, outlen,
                                 LTC_ASN1_INTEGER, 1UL, key->N,
                                 LTC_ASN1_EOL,     0UL, NULL);
   }
}

#endif /* LTC_MRSA */

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */