prob2.c 핸드레이

prob2.c

Dump of assembler code for function main:
0x8048470 <main>:    push   %ebp //새로운 스택프레임 형성 
0x8048471 <main+1>:    mov    %ebp,%esp
0x8048473 <main+3>:    sub    %esp,16 //16바이트 공간 할당 
0x8048476 <main+6>:    lea    %eax,[%ebp-16]
0x8048479 <main+9>:    push   %eax //변수의 첫번째 주소 push 
0x804847a <main+10>:    push   0x8048560 // '%s' push
0x804847f <main+15>:    call   0x8048358 <scanf> //파라미터 2개 
0x8048484 <main+20>:    add    %esp,8 //인자 2개 주소(4byte*2)만큼 추가 
0x8048487 <main+23>:    lea    %eax,[%ebp-16] 
0x804848a <main+26>:    push   %eax
0x804848b <main+27>:    call   0x8048378 <strlen>
0x8048490 <main+32>:    add    %esp,4
0x8048493 <main+35>:    mov    %eax,%eax
0x8048495 <main+37>:    cmp    %eax,4
0x8048498 <main+40>:    jbe    0x80484b0 <main+64>
0x804849a <main+42>:    lea    %eax,[%ebp-16]
0x804849d <main+45>:    push   %eax
0x804849e <main+46>:    call   0x8048378 <strlen>
0x80484a3 <main+51>:    add    %esp,4 //strlen(str)>4
0x80484a6 <main+54>:    mov    %eax,%eax
0x80484a8 <main+56>:    cmp    %eax,15
0x80484ab <main+59>:    ja     0x80484b0 <main+64>
0x80484ad <main+61>:    jmp    0x80484b4 <main+68>
0x80484af <main+63>:    nop    
0x80484b0 <main+64>:    xor    %eax,%eax //
0x80484b2 <main+66>:    jmp    0x804850d <main+157>
0x80484b4 <main+68>:    push   6 //6
0x80484b6 <main+70>:    push   0x8048563 //"impossXXXX"
0x80484bb <main+75>:    lea    %eax,[%ebp-16] 
0x80484be <main+78>:    push   %eax //16byte
0x80484bf <main+79>:    call   0x8048388 <strncmp> //strncmp(str)
0x80484c4 <main+84>:    add    %esp,12
0x80484c7 <main+87>:    mov    %eax,%eax
0x80484c9 <main+89>:    test   %eax,%eax //같으면 0 
0x80484cb <main+91>:    je     0x80484d1 <main+97> //
0x80484cd <main+93>:    xor    %eax,%eax //초기화 
0x80484cf <main+95>:    jmp    0x804850d <main+157>
0x80484d1 <main+97>:    cmp    BYTE PTR [%ebp-7],0x45 //9번째 자리랑 69(e) 
0x80484d5 <main+101>:    je     0x80484e0 <main+112> 
0x80484d7 <main+103>:    xor    %eax,%eax //초기화 
0x80484d9 <main+105>:    jmp    0x804850d <main+157>
0x80484db <main+107>:    nop     //필요 x 
0x80484dc <main+108>:    lea    %esi,[%esi*1] // 필요x 
0x80484e0 <main+112>:    cmp    BYTE PTR [%ebp-10],0x21 //6index 33(!)
0x80484e4 <main+116>:    jne    0x80484f8 <main+136> //리턴 
0x80484e6 <main+118>:    cmp    BYTE PTR [%ebp-9],0x42 //7index B
0x80484ea <main+122>:    jne    0x80484f2 <main+130> //리턴 
0x80484ec <main+124>:    mov    BYTE PTR [%ebp-8],0x31 //8index 1
0x80484f0 <main+128>:    jmp    0x80484f6 <main+134> //성공 
0x80484f2 <main+130>:    xor    %eax,%eax
0x80484f4 <main+132>:    jmp    0x804850d <main+157>
0x80484f6 <main+134>:    jmp    0x8048500 <main+144>
0x80484f8 <main+136>:    xor    %eax,%eax //초기화 
0x80484fa <main+138>:    jmp    0x804850d <main+157>
0x80484fc <main+140>:    lea    %esi,[%esi*1]
0x8048500 <main+144>:    push   0x804856e //success
0x8048505 <main+149>:    call   0x80483a8 <printf>
0x804850a <main+154>:    add    %esp,4
0x804850d <main+157>:    leave  
0x804850e <main+158>:    ret    
0x804850f <main+159>:    nop    
End of assembler dump.
 
(gdb) x/s 0x8048560
0x8048560 <_IO_stdin_used+4>:     "%s"
 
(gdb) x/s 0x8048563
0x8048563 <_IO_stdin_used+7>:     "impossXXXX"
 
(gdb) x/s 0x804856e
0x804856e <_IO_stdin_used+18>:     "Success\n"

핸드레이

#include<stdio.h>
#include<string.h> 
 
void main(){
    char str[16];
    scanf("%s",str);
    if(strlen(str)<=4&&strlen(str)>15){
        return 0;
    }
    if(strncmp(str,"impossXXXX",6)==0){
        if(str[9]=='E'){
            if(str[6]=='!'){
                if(str[7]=='B'){
                    str[8]='1';
                }
            }
        }
    }else{
        return 0;
    }
}