view libtomcrypt/src/pk/katja/katja_import.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_import.c
  Import a PKCS-style Katja key, Tom St Denis
*/

#ifdef LTC_MKAT

/**
  Import an KatjaPublicKey or KatjaPrivateKey [two-prime only, only support >= 1024-bit keys, defined in PKCS #1 v2.1]
  @param in      The packet to import from
  @param inlen   It's length (octets)
  @param key     [out] Destination for newly imported key
  @return CRYPT_OK if successful, upon error allocated memory is freed
*/
int katja_import(const unsigned char *in, unsigned long inlen, katja_key *key)
{
   int           err;
   void         *zero;

   LTC_ARGCHK(in  != NULL);
   LTC_ARGCHK(key != NULL);
   LTC_ARGCHK(ltc_mp.name != NULL);

   /* init key */
   if ((err = mp_init_multi(&zero, &key->d, &key->N, &key->dQ,
                            &key->dP, &key->qP, &key->p, &key->q, &key->pq, NULL)) != CRYPT_OK) {
      return err;
   }

   if ((err = der_decode_sequence_multi(in, inlen,
                                  LTC_ASN1_INTEGER, 1UL, key->N,
                                  LTC_ASN1_EOL,     0UL, NULL)) != CRYPT_OK) {
      goto LBL_ERR;
   }

   if (mp_cmp_d(key->N, 0) == LTC_MP_EQ) {
      /* it's a private key */
      if ((err = der_decode_sequence_multi(in, inlen,
                          LTC_ASN1_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) {
         goto LBL_ERR;
      }
      key->type = PK_PRIVATE;
   } else {
      /* public we have N */
      key->type = PK_PUBLIC;
   }
   mp_clear(zero);
   return CRYPT_OK;
LBL_ERR:
   mp_clear_multi(zero,    key->d, key->N, key->dQ, key->dP,
                  key->qP, key->p, key->q, key->pq, NULL);
   return err;
}

#endif /* LTC_MRSA */


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