protostar

user@protostar:~$ ./stack5 < s5
Illegal instruction

user@protostar:~$ clear

user@protostar:~$ gdb -q stack5
Reading symbols from /home/user/stack5...done.

(gdb) disassemble main
Dump of assembler code for function main:
0x080483c4 <main+0>:    push   ebp
0x080483c5 <main+1>:    mov    ebp,esp
0x080483c7 <main+3>:    and    esp,0xfffffff0
0x080483ca <main+6>:    sub    esp,0x50
0x080483cd <main+9>:    lea    eax,[esp+0x10]
0x080483d1 <main+13>:   mov    DWORD PTR [esp],eax
0x080483d4 <main+16>:   call   0x80482e8 <gets@plt>
0x080483d9 <main+21>:   leave
0x080483da <main+22>:   ret
End of assembler dump.

(gdb) break *0x080483da
Breakpoint 1 at 0x80483da: file stack5/stack5.c, line 11.

(gdb) define hook-stop
Type commands for definition of "hook-stop".
End with a line saying just "end".
>x/1i $eip
>x/8wx $esp
>end

(gdb) r < s5
Starting program: /home/user/stack5 < s5
0x80483da <main+22>:    ret
0xbffff7ec:     0xbffff80c      0x90909090      0x90909090      0x90909090
0xbffff7fc:     0x90909090      0x90909090      0x90909090      0x90909090

Breakpoint 1, 0x080483da in main (argc=Cannot access memory at address 0x5353535b
) at stack5/stack5.c:11
11      stack5/stack5.c: No such file or directory.
        in stack5/stack5.c
(gdb) si
Cannot access memory at address 0x53535357

(gdb)
0xbffff80d:     nop
0xbffff7f0:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff800:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff80d in ?? ()

(gdb)
0xbffff80e:     nop
0xbffff7f0:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff800:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff80e in ?? ()

(gdb)
0xbffff80f:     nop
0xbffff7f0:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff800:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff80f in ?? ()
(gdb) c
Continuing.

Program received signal SIGTRAP, Trace/breakpoint trap.
0xbffff871:     int3
0xbffff7f0:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff800:     0x90909090      0x90909090      0x90909090      0x90909090
0xbffff871 in ?? ()
(gdb) q
A debugging session is active.

        Inferior 1 [process 2077] will be killed.

Quit anyway? (y or n) y
user@protostar:~$ ./stack5 < s5
Illegal instruction
user@protostar:~$