stack-five exploit education

Step 1. gdb stack-five
Step 2. disass main
	output:
	Dump of assembler code for function main:
   	0x000000000000114c <+0>:	push   %rbp
   	0x000000000000114d <+1>:	mov    %rsp,%rbp
   	0x0000000000001150 <+4>:	sub    $0x10,%rsp
   	0x0000000000001154 <+8>:	mov    %edi,-0x4(%rbp)
   	0x0000000000001157 <+11>:	mov    %rsi,-0x10(%rbp)
   	0x000000000000115b <+15>:	mov    $0x0,%eax
   	0x0000000000001160 <+20>:	callq  0x1135 <start_level>
   	0x0000000000001165 <+25>:	mov    $0x0,%eax
   	0x000000000000116a <+30>:	leaveq
   	0x000000000000116b <+31>:	retq
Step 3. break *0x116b
	output:
	Breakpoint 1 at 0x116b: line 23.
Step 4. run
	output:
	Starting program: /opt/phoenix/amd64/stack-five

	[1]+  Stopped                 gdb stack-five