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Microsoft Windows "April Fools 2001" Vulnerability


//
// APRIL1.C -- Simple test program for the "April's Fools 2001" bug
//
// by Richard M. Smith (rms@pharlap.com)
// copyright (C) 1999
//

#include <stdio.h>
#include <time.h>
#include <string.h>

#define SECS_PER_HOUR (60 * 60)
#define SECS_PER_DAY (24 * SECS_PER_HOUR)
#define SECS_PER_YEAR (365 * SECS_PER_DAY)

#define START (3 * SECS_PER_DAY)
#define INCR (23 * SECS_PER_HOUR)
#define MAXTIMES ((0x80000000L - START) / INCR)

void print_time(time_t mytime);

char *month_tab[] =
{
"January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"
};

char *dow_tab[] =
{
"Sunday",
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday"
};

int main()

{

print_time(0x3AC796D0); // Sunday, April 1, 2001
print_time(0x3ACF2B70); // Saturday, April 7, 2001
print_time(0x3AD06EE0); // Sunday, April 8, 2001
return 0;

}

//
// print_time -- print out a time_t value converted by localtime()
//

void print_time(time_t mytime)

{

char month[100];
char dow[100];
struct tm *tmp;

tmp = localtime(&mytime);
if(tmp == NULL)
{
printf("0x%08lX = Invalid time\n", mytime);
return;
}
if(tmp->tm_mon >= 0 && tmp->tm_mon <= 11)
strcpy(month, month_tab[tmp->tm_mon]);
else
sprintf(month, "BadMonth=%d", tmp->tm_mon);
if(tmp->tm_wday >= 0 && tmp->tm_wday <= 6)
strcpy(dow, dow_tab[tmp->tm_wday]);
else
sprintf(month, "BadDOW=%d", tmp->tm_wday);
printf("0x%08lX = %s, %s %d, %d -- %d:%02d:%02d %s -- DOY=%d\n",
mytime, dow, month, tmp->tm_mday, tmp->tm_year + 1900,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec, _tzname[tmp->tm_isdst != 0],
tmp->tm_yday);
return;