view libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_multi.c @ 994:5c5ade336926

Prefer stronger algorithms in algorithm negotiation. Prefer diffie-hellman-group14-sha1 (2048 bit) over diffie-hellman-group1-sha1 (1024 bit). Due to meet-in-the-middle attacks the effective key length of three key 3DES is 112 bits. AES is stronger and faster then 3DES. Prefer to delay the start of compression until after authentication has completed. This avoids exposing compression code to attacks from unauthenticated users. (github pull request #9)
author Fedor Brunner <fedor.brunner@azet.sk>
date Fri, 23 Jan 2015 23:00:25 +0800
parents 0cbe8f6dbf9e
children f849a5ca2efc
line wrap: on
line source

/* 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.
 *
 * Tom St Denis, [email protected], http://libtomcrypt.com
 */
#include "tomcrypt.h"
#include <stdarg.h>


/**
  @file der_decode_sequence_multi.c
  ASN.1 DER, decode a SEQUENCE, Tom St Denis
*/

#ifdef LTC_DER

/**
  Decode a SEQUENCE type using a VA list
  @param in    Input buffer
  @param inlen Length of input in octets
  @remark <...> is of the form <type, size, data> (int, unsigned long, void*)
  @return CRYPT_OK on success
*/  
int der_decode_sequence_multi(const unsigned char *in, unsigned long inlen, ...)
{
   int           err, type;
   unsigned long size, x;
   void          *data;
   va_list       args;
   ltc_asn1_list *list;

   LTC_ARGCHK(in    != NULL);

   /* get size of output that will be required */
   va_start(args, inlen);
   x = 0;
   for (;;) {
       type = va_arg(args, int);
       size = va_arg(args, unsigned long);
       data = va_arg(args, void*);

       if (type == LTC_ASN1_EOL) { 
          break;
       }

       switch (type) {
           case LTC_ASN1_BOOLEAN:
           case LTC_ASN1_INTEGER:
           case LTC_ASN1_SHORT_INTEGER:
           case LTC_ASN1_BIT_STRING:
           case LTC_ASN1_OCTET_STRING:
           case LTC_ASN1_NULL:
           case LTC_ASN1_OBJECT_IDENTIFIER:
           case LTC_ASN1_IA5_STRING:
           case LTC_ASN1_PRINTABLE_STRING:
           case LTC_ASN1_UTF8_STRING:
           case LTC_ASN1_UTCTIME:
           case LTC_ASN1_SET:
           case LTC_ASN1_SETOF:
           case LTC_ASN1_SEQUENCE:
           case LTC_ASN1_CHOICE:
                ++x; 
                break;
          
           default:
               va_end(args);
               return CRYPT_INVALID_ARG;
       }
   }
   va_end(args);

   /* allocate structure for x elements */
   if (x == 0) {
      return CRYPT_NOP;
   }

   list = XCALLOC(sizeof(*list), x);
   if (list == NULL) {
      return CRYPT_MEM;
   }

   /* fill in the structure */
   va_start(args, inlen);
   x = 0;
   for (;;) {
       type = va_arg(args, int);
       size = va_arg(args, unsigned long);
       data = va_arg(args, void*);

       if (type == LTC_ASN1_EOL) { 
          break;
       }

       switch (type) {
           case LTC_ASN1_BOOLEAN:
           case LTC_ASN1_INTEGER:
           case LTC_ASN1_SHORT_INTEGER:
           case LTC_ASN1_BIT_STRING:
           case LTC_ASN1_OCTET_STRING:
           case LTC_ASN1_NULL:
           case LTC_ASN1_OBJECT_IDENTIFIER:
           case LTC_ASN1_IA5_STRING:
           case LTC_ASN1_PRINTABLE_STRING:
           case LTC_ASN1_UTF8_STRING:
           case LTC_ASN1_UTCTIME:
           case LTC_ASN1_SEQUENCE:
           case LTC_ASN1_SET:
           case LTC_ASN1_SETOF:          
           case LTC_ASN1_CHOICE:
                list[x].type   = type;
                list[x].size   = size;
                list[x++].data = data;
                break;
         
           default:
               va_end(args);
               err = CRYPT_INVALID_ARG;
               goto LBL_ERR;
       }
   }
   va_end(args);

   err = der_decode_sequence(in, inlen, list, x);
LBL_ERR:
   XFREE(list);
   return err;
}

#endif


/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_multi.c,v $ */
/* $Revision: 1.12 $ */
/* $Date: 2006/11/26 02:25:18 $ */