gnupg/cipher/rand-dummy.c

/* rand-dummy.c  -  INSECURE dummy random device
 *	Copyright (C) 1998 Free Software Foundation, Inc.
 *
 * This file is part of GNUPG.
 *
 * GNUPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GNUPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */


#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef	HAVE_GETHRTIME
  #include <sys/times.h>
#endif
#ifndef HAVE_GETTIMEOFTIME
  #include <sys/times.h>
#endif
#ifdef HAVE_GETRUSAGE
  #include <sys/resource.h>
#endif
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "util.h"
#include "ttyio.h"
#include "i18n.h"
#include "rand-internal.h"
#ifdef USE_RAND_DUMMY /* a dummy random file so we can do some tests */


#ifndef RAND_MAX   /* for SunOS */
  #define RAND_MAX 32767
#endif

#if __GNUC__
  #warning Using the insecure dummy random device
#endif

void
random_poll()
{
    char buf[POOLSIZE/5];
    read_random_source( buf, POOLSIZE/5, 1 ); /* read dummy data */
    add_randomness( buf, POOLSIZE/5, 2);
    memset( buf, 0, POOLSIZE/5);
}


void
fast_random_poll()
{
  #if HAVE_GETHRTIME
    {	hrtime_t tv;
	tv = gethrtime(void);
	add_randomness( &tv, sizeof(tv), 1 );
    }
  #elif HAVE_GETTIMEOFTIME
    {	struct timeval tv;
	if( gettimeofday( &tv, NULL ) )
	    BUG();
	add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
	add_randomness( &tv.tv_usec, sizeof(tv.tv_usec), 1 );
    }
  #else /* use times */
    {	struct tms buf;
	times( &buf );
	add_randomness( &buf, sizeof buf, 1 );
    }
  #endif
  #ifdef HAVE_GETRUSAGE
    {	struct rusage buf;
	if( getrusage( RUSAGE_SELF, &buf ) )
	    BUG();
	add_randomness( &buf, sizeof buf, 1 );
	memset( &buf, 0, sizeof buf );
    }
  #endif
}



void
read_random_source( byte *buffer, size_t length, int level )
{
    static int initialized=0;

    if( !initialized ) {
	log_info(_("warning: using insecure random number generator!!\n"));
	tty_printf(_("The random number generator is only a kludge to let\n"
		   "it compile - it is in no way a strong RNG!\n\n"
		   "DON'T USE ANY DATA GENERATED BY THIS PROGRAM!!\n\n"));
	initialized=1;
      #ifdef HAVE_RAND
	srand(make_timestamp()*getpid());
      #else
	srandom(make_timestamp()*getpid());
      #endif
    }

  #ifdef HAVE_RAND
    while( length-- )
	*buffer++ = ((unsigned)(1 + (int) (256.0*rand()/(RAND_MAX+1.0)))-1);
  #else
    while( length-- )
	*buffer++ = ((unsigned)(1 + (int) (256.0*random()/(RAND_MAX+1.0)))-1);
  #endif
}


#endif /* USE_RAND_DUMMY */