Question

8. Rewrite the function shown below so that it is no longer vulnerable to a stack buffer overflow i void gctinp (ohar *inp, int siz) puts (" Input value "); fgets (inp, siz, stdin); printf("buffer3 getinp read %s\n", inp); 3 4 6 7 void display (char *val) 8 9 10 char tmp [16]; sprintf(tmp, "read val: puts (tmp); %s\n", val); 12 13 int main(int argc, char *argv []) 14 15 16 char buf [16]; getinp (buf, sizeof (buf)); 17 18 19 display (buf); printf ("buffer3 done\n");

Answer 1

Answer:-

The below is the required source code for the given problem

Code:-

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

void getinput(char * inp, int size)
{
int extra,ch;
    puts("Enter the input");
    fgets(inp,size,stdin);
    printf("got input\n");
if (inp[strlen(inp)-1] != '\n') {
        extra = 0;
        while (((ch = getchar()) != '\n') && (ch != EOF))
            extra = 1;
}
        if(extra == 1)
{
  printf("Too long to fit. Enter Again(Max length is %d)",size);
  exit(0);
}
}

void display(char * inp)
{
    char temp[16];
    sprintf(temp,"read value: %s \n",inp);
    puts(temp);
}

int main()
{
    char buf[16];
    getinput(buf,sizeof(buf));
    display(buf);
    printf("Buffer Done");
}

Sample Output 1 & 2:-

null

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