// create a password that will take iter_count iterations to crack
void createPassword(char *password, char *pw_prefix, int iter_count) {
assert(iter_count > 0);
// first randomize the whole thing
randomizeString(password, PASSWORD_LEN);
strcpy(pw_prefix, password);
// now convert iter_count into a base 26 number
int digit_pos = PASSWORD_LEN - 1;
iter_count--; // subtract 1 since iter_count is being used as an offset
while (iter_count > 0) {
int digit = iter_count % 26;
password[digit_pos] = 'a' + digit;
pw_prefix[digit_pos] = '.';
iter_count /= 26;
digit_pos--;
}
// *prefix_len = PASSWORD_LEN - digit_pos;
}
int main( int argc, char ** argv )
{
#define BUF_SIZE 16
#define TOTAL_COPY_CHECKS 1024
char mem[ BUF_SIZE ] ;
char buf[ BUF_SIZE * BUF_MULTIPLICITY ] ;
char copy[ BUF_SIZE ] ;
int numCopies = 0 ;
int iterations = 0 ;
int verbose = VERBOSE ;
initializeBuffer( mem, sizeof(mem) ) ;
for ( ; numCopies < TOTAL_COPY_CHECKS ; iterations++ )
{
RETRY:
char * src = randomizeString( buf, mem, BUF_SIZE ) ;
size_t len = strlen( src ) ;
assert( len < BUF_SIZE ) ;
strcpy( copy, src ) ;
char * dest ;
ssize_t diff ;
for ( int n = 0 ; ; )
{
#if defined OVERLAPPED
dest = &buf[ rand() % ( sizeof(buf) - 1 ) ] ;
#else
dest = &buf[ BUF_SIZE + rand() % ( BUF_SIZE - 1 ) ] ;
#endif
diff = dest - src ;
//#define REQUIRE_DEST_LESSER_THAN_SRC
#if defined REQUIRE_DEST_LESSER_THAN_SRC
if ( diff > 0 )
{
continue ;
}
#endif
if ( diff < 0 )
{
diff = -diff ;
}
if ( pred( diff, len ) && (&dest[len + 1] < &buf[BUF_SIZE * BUF_MULTIPLICITY -1]) )
{
break ;
}
if ( ++n > 3 )
{
goto RETRY ;
}
}
if ( verbose )
{
printf( "buf:\t[%p, %p]\n"
"dest:\t[%p, %p]\n"
"src:\t[%p, %p]\n"
"strlen + 1:\t%u\n"
"diff:\t%d\n",
buf,
buf + sizeof(buf) - 1,
dest,
dest + len + 1,
src,
src + len + 1,
(unsigned)len + 1,
(int)diff ) ;
}
else
{
printf( "." ) ;
if ( (0 == (numCopies % 80)) && numCopies )
{
printf( "\n" ) ;
}
}
numCopies++ ;
systemStrcpy( dest, src ) ;
if ( 0 != strcmp( dest, copy ) )
{
printf( "pattern: '%s'\n"
"dest: '%s'\n"
"src: %p\n"
"dest: %p\n"
"diff: %d\n"
"strlen + 1: %u\n",
copy,
dest,
src,
dest,
(int)diff,
(unsigned)len + 1 ) ;
break ;
}
}
printf( "\nDONE\n" ) ;
return iterations ;
}
