ReversingKR - Easy Crack

Easy Crack

以下为 Ghidra 反编译的密码校验函数摘录，类型、全局符号和字符串常量由原二进制提供，不是可独立编译的 C 程序。入口和窗口初始化代码不影响校验，未列入此段。

void __cdecl checkPassword(HWND param_1)

{
  byte bVar1;
  byte *pbVar2;
  int iVar3;
  char *pcVar4;
  bool bVar5;

  CHAR local_64;
  char local_63;
  char local_62;
  char acStack_61 [97];

  local_64 = '\0';
  pcVar4 = &local_63;
  for (iVar3 = 0x18; iVar3 != 0; iVar3 = iVar3 + -1) {
    pcVar4[0] = '\0';
    pcVar4[1] = '\0';
    pcVar4[2] = '\0';
33 collapsed lines
    pcVar4[3] = '\0';
    pcVar4 = pcVar4 + 4;
  }
  pcVar4[0] = '\0';
  pcVar4[1] = '\0';
  pcVar4[2] = '\0';
  GetDlgItemTextA(param_1,1000,&local_64,100);
  if (local_63 == 'a') {                            // a
    iVar3 = _strncmp(&local_62,&DAT_00406078,2);    // 5y
    if (iVar3 == 0) {
      pcVar4 = s_AGR3versing_0040606a;
      pbVar2 = (byte *)(acStack_61 + 1);

      do {
        pcVar4 = (char *)((byte *)pcVar4 + 2);      // R3versing
        bVar1 = *pbVar2;
        bVar5 = bVar1 < (byte)*pcVar4;
        if (bVar1 != *pcVar4) {
LAB_00401102:
          iVar3 = (1 - (uint)bVar5) - (uint)(bVar5 != 0);
          goto LAB_00401107;
        }
        if (bVar1 == 0) break;
        bVar1 = pbVar2[1];
        bVar5 = bVar1 < ((byte *)pcVar4)[1];
        if (bVar1 != ((byte *)pcVar4)[1]) goto LAB_00401102;
        pbVar2 = pbVar2 + 2;
      } while (bVar1 != 0);

      iVar3 = 0;
LAB_00401107:
      if ((iVar3 == 0) && (local_64 == 'E')) {   // E
        MessageBoxA(param_1,s_Congratulation_!!_00406044,s_EasyCrackMe_00406058,0x40);
        EndDialog(param_1,0);
        return;
      }
    }
  }
  MessageBoxA(param_1,s_Incorrect_Password_00406030,s_EasyCrackMe_00406058,0x10);
  return;
}

Ea5yR3versing

IDA 对同一校验逻辑的反编译摘录如下。String[1]、String[2:4]、String[4:] 和 String[0] 的检查分别约束输入的对应片段；符号 Str2 和 aR3versing 的字符串内容须从原二进制读取。

int __cdecl sub_401080(HWND hDlg)
{
  CHAR String[97]; // [esp+4h] [ebp-64h] BYREF
  __int16 v3; // [esp+65h] [ebp-3h]
  char v4; // [esp+67h] [ebp-1h]

  memset(String, 0, sizeof(String));
  v3 = 0;
  v4 = 0;
  GetDlgItemTextA(hDlg, 1000, String, 100);
  if ( String[1] != 'a' || strncmp(&String[2], Str2, 2u) || strcmp(&String[4], aR3versing) || String[0] != 69 )
    return MessageBoxA(hDlg, aIncorrectPassw, Caption, 0x10u);
  MessageBoxA(hDlg, Text, Caption, 0x40u);
  return EndDialog(hDlg, 0);
}