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/* mcookie.c -- Generates random numbers for xauth
* Created: Fri Feb 3 10:42:48 1995 by faith@cs.unc.edu
* Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
* Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
* This program comes with ABSOLUTELY NO WARRANTY.
*
* This program gathers some random bits of data and used the MD5
* message-digest algorithm to generate a 128-bit hexadecimal number for
* use with xauth(1).
*
* NOTE: Unless /dev/random is available, this program does not actually
* gather 128 bits of random information, so the magic cookie generated
* will be considerably easier to guess than one might expect.
*
* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
* 1999-03-21 aeb: Added some fragments of code from Colin Plumb.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include "md5.h"
#include <sys/time.h>
#include <unistd.h>
#include "nls.h"
#define BUFFERSIZE 4096
struct rngs {
const char *path;
int minlength, maxlength;
} rngs[] = {
{ "/dev/random", 16, 16 }, /* 16 bytes = 128 bits suffice */
{ "/proc/interrupts", 0, 0 },
{ "/proc/slabinfo", 0, 0 },
{ "/proc/stat", 0, 0 },
{ "/dev/urandom", 32, 64 },
};
#define RNGS (sizeof(rngs)/sizeof(struct rngs))
int Verbose = 0;
/* The basic function to hash a file */
static off_t
hash_file(struct MD5Context *ctx, int fd)
{
off_t count = 0;
ssize_t r;
unsigned char buf[BUFFERSIZE];
while ((r = read(fd, buf, sizeof(buf))) > 0) {
MD5Update(ctx, buf, r);
count += r;
}
/* Separate files with a null byte */
buf[0] = 0;
MD5Update(ctx, buf, 1);
return count;
}
int main( int argc, char **argv )
{
int i;
struct MD5Context ctx;
unsigned char digest[16];
unsigned char buf[BUFFERSIZE];
int fd;
int c;
pid_t pid;
char *file = NULL;
int r;
struct timeval tv;
struct timezone tz;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
while ((c = getopt( argc, argv, "vf:" )) != -1)
switch (c) {
case 'v': ++Verbose; break;
case 'f': file = optarg; break;
}
MD5Init( &ctx );
gettimeofday( &tv, &tz );
MD5Update( &ctx, (unsigned char *)&tv, sizeof( tv ) );
pid = getppid();
MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
pid = getpid();
MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
if (file) {
int count = 0;
if (file[0] == '-' && !file[1])
fd = fileno(stdin);
else
fd = open( file, O_RDONLY );
if (fd < 0) {
fprintf( stderr, _("Could not open %s\n"), file );
} else {
count = hash_file( &ctx, fd );
if (Verbose)
fprintf( stderr, _("Got %d bytes from %s\n"), count, file );
if (file[0] != '-' || file[1]) close( fd );
}
}
for (i = 0; i < RNGS; i++) {
if ((fd = open( rngs[i].path, O_RDONLY|O_NONBLOCK )) >= 0) {
int count = sizeof(buf);
if (rngs[i].maxlength && count > rngs[i].maxlength)
count = rngs[i].maxlength;
r = read( fd, buf, count );
if (r > 0)
MD5Update( &ctx, buf, r );
else
r = 0;
close( fd );
if (Verbose)
fprintf( stderr, _("Got %d bytes from %s\n"), r, rngs[i].path );
if (rngs[i].minlength && r >= rngs[i].minlength)
break;
} else if (Verbose)
fprintf( stderr, _("Could not open %s\n"), rngs[i].path );
}
MD5Final( digest, &ctx );
for (i = 0; i < 16; i++) printf( "%02x", digest[i] );
putchar ( '\n' );
/*
* The following is important for cases like disk full, so shell scripts
* can bomb out properly rather than think they succeeded.
*/
if (fflush(stdout) < 0 || fclose(stdout) < 0)
return 1;
return 0;
}
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