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

void overflow(char* source) {
    char buffer[6];

    printf("Copying %d bytes to buffer...\n",strlen(source));


    if (strlen(source)>=6)
        strcpy(buffer,source);
}

int main(int argc, char *argv[]) {
    if (argc > 1)
        overflow(argv[1]);

    printf("Exploit fail, better luck next time...\n");

    return 0;
}

/*
    shorter version
* */

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


int main(int argc, char *argv[]) {
    if (argc > 1) {
        char* source = argv[1];
        char buffer[6];

        printf("Copying %d bytes to buffer...\n", strlen(source));

        if (strlen(source) <= 6) {
            printf("Exploit fail, better luck next time...\n");
            strcpy(buffer, source);
        }
    }

    return 0;
}

/*
 *  fgets attack
 * */


#include <stdio.h>



void execs(void){
    printf("yay!!");
}

void return_input (void)
{
    char array[30];
    fgets(array,30,stdin);

}

int main()
{

    return_input();
    execs(); /* only runs if char array is less than 30 */
    return 0;
}

/*
 *  fgets attack shortened
 * */

#include <stdio.h>


int main()
{
    printf("yay!!");

    char array[30];
    fgets(array,30,stdin);

    return 0;
}

/*
 *  scanf attack
 * */

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>


int main()
{
    int bytes_read;
    int nbytes = 100;
    char *stringA, *stringB;

    stringA = (char *) malloc (25);

    puts ("Please enter a string of 20 characters or fewer.");
    scanf ("%20s", stringA);
    printf ("\nYou typed the following string:\n%s\n\n", stringA);

    puts ("Now enter a string of any length.");
    scanf ("%as", &stringB);
    printf ("\nYou typed the following string:\n%s\n", stringB);

    return 0;
}