int check_payload_extract_header(payload_check *this) {
  payload_check *payload_struc;
  int encrypted;
  int decrypted;
  int payload_size;
  bool v5;
  int v6;
  unsigned int v7;
  int i;
  int v9;
  int v10;
  unsigned int v11;
  int v12;
  signed int return_value;

  payload_struc = this;
  return_value = 0;
  if ( payload_struc )
  {
    encrypted = payload_struc->payload_encrypted;
    decrypted = payload_struc->payload_decrypted;
    payload_size = payload_struc->size;           
    if ( encrypted & decrypted &  payload_struc->size > 832u)
    {
          v7 = (unsigned int)payload_size >> 2;
          memcpy((void *)decrypted, (const void *)encrypted, 4 * v7);
          memcpy((void *)(decrypted + 4 * v7), (const void *)(encrypted + 4 * v7),
                  payload_struc->size & 3);
          /* decrypt encrypted payload */
          v5 = rsa_validation_rc4_decryption(
                 Modulus_,
                 Exponent,
                 payload_struc->payload_decrypted + payload_struc->size - 512,
                 payload_struc->payload_decrypted,
                 payload_struc->size - 512);
          if (v5 ) {  
              /* succesful signature validation */
              memset((void *)(payload_struc->size + payload_struc->payload_decrypted
                     - 512), 0, 0x200u);
              /* copy the first 64 bytes (size of the payload header) of the decrypted
                 payload */
              memcpy(payload_struc->decrypted_header, (const void *)
                     payload_struc->payload_decrypted,
                     sizeof(payload_struc->decrypted_header));
              return_value = 1;
          }
          else /* signature validation check fails*/
          {
              v10 = payload_struc->size;
              v11 = (unsigned int)payload_struc->size >> 2;
              v12 = payload_struc->payload_decrypted;
              memset((void *)v12, 0, 4 * v11); /* zero out decrypted content */
              v9 = v12 + 4 * v11;
             for ( i = v10 & 3; i; --i )
                  *(_BYTE *)v9++ = v5;
          }
     }
  }
  return return_value;
}





 

 

Acknowledements

  This material is based upon work supported through the U.S. Army Research Office under the Cyber-TA Research Grant No. W911NF-06-1- 0316 and by the National Science Foundation, Grant No. CNS-07-16 612. The views expressed in this document are those of the authors and do not necessarily represent the official position of the sponsors.