view libtomcrypt/src/pk/asn1/der/printable_string/der_decode_printable_string.c @ 1861:2b3a8026a6ce

Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
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 der_decode_printable_string.c
  ASN.1 DER, encode a printable STRING, Tom St Denis
*/


#ifdef LTC_DER

/**
  Store a printable STRING
  @param in      The DER encoded printable STRING
  @param inlen   The size of the DER printable STRING
  @param out     [out] The array of octets stored (one per char)
  @param outlen  [in/out] The number of octets stored
  @return CRYPT_OK if successful
*/
int der_decode_printable_string(const unsigned char *in, unsigned long inlen,
                                unsigned char *out, unsigned long *outlen)
{
   unsigned long x, y, len;
   int           t;

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

   /* must have header at least */
   if (inlen < 2) {
      return CRYPT_INVALID_PACKET;
   }

   /* check for 0x13 */
   if ((in[0] & 0x1F) != 0x13) {
      return CRYPT_INVALID_PACKET;
   }
   x = 1;

   /* decode the length */
   if (in[x] & 0x80) {
      /* valid # of bytes in length are 1,2,3 */
      y = in[x] & 0x7F;
      if ((y == 0) || (y > 3) || ((x + y) > inlen)) {
         return CRYPT_INVALID_PACKET;
      }

      /* read the length in */
      len = 0;
      ++x;
      while (y--) {
         len = (len << 8) | in[x++];
      }
   } else {
      len = in[x++] & 0x7F;
   }

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

   if (len + x > inlen) {
      return CRYPT_INVALID_PACKET;
   }

   /* read the data */
   for (y = 0; y < len; y++) {
       t = der_printable_value_decode(in[x++]);
       if (t == -1) {
           return CRYPT_INVALID_ARG;
       }
       out[y] = t;
   }

   *outlen = y;

   return CRYPT_OK;
}

#endif

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