Buffer overflow example in C

demo2.c

// Demo 1
// clang -fno-stack-protector -fno-sanitize=safe-stack -D_FORTIFY_SOURCE=0 -m32 -Wl,-no_pie -O0 -g demo2.c -o demo2.o

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

char password[] = "password";

int get_password() {
    int auth_ok = 0;
    char buff[16];

    printf("Enter password: ");
    scanf("%s", buff);

    if(strncmp(buff, password, sizeof(password)) == 0)
        auth_ok = 1;

    return auth_ok;
}

void success() {
    printf("Success!\n");
}

int main(int argc, char** argv) {
    
    int res = get_password();

    if (res == 0) {
        printf("Failure\n");
        return 0;
    }

    success();
    
    return 0;
}