Question

What security flaw(s) might exist in the following C software? void chopUserInput( char *mon, char *day, char *input ) { char *m, *d; m = strtok( input, “/”); d = strtok( NULL, “/” ); strcpy( mon, m ); strcpy( day, d ); }

Answer 1

Code:

#include <stdio.h>

#include <string.h>

void chopUserInput( char *mon, char *day, char *input )

{

char *m, *d;

m = strtok(input,"/");

d = strtok(NULL,"/");

strcpy( mon, m );

strcpy( day, d );

}

int main()

{

char *input=NULL;

char mon[4],day[4];

printf("Enter date in mon/day format : ");

scanf("%s",input);

chopUserInput(mon,day,input);

printf("\nMonth name : %s",mon);

printf("\nDay name : %s",day);

return 0;

}

Explanation: In the above code “main()” is calling function and “chopUserInput()” is called function. The actual parameters passed from “main()” is “mon” and “day” are modified by sub function “chopUserInput()”. So that each modification in sub function is visible and accessible by calling function “main()”.