ida分析readFile相关函数遇到问题

白云点缀的蓝 · 发表于 2021-7-24 01:25

希望有大佬能分析代码的相关逻辑,
写一下注释,翻译一下就行,我可以自己写提取代码,感谢
输入假码获取相关关键信息分析.jpg

通过搜索关键字符串,定位到如下代码
分析1.jpg

再次点击播放出现如下信息
分析2.jpg

我们用相关加密软件加密其他视频,然后分析看看,是否为秘钥
分析3.jpg

再次定位到弹出错误的地方,然后出现如下信息

分析4.jpg

我们分析一下加密软件的播放算法

分析01.jpg

经过定位点击按钮的事件,我们在od中找到了加密call

加密软件默认加密秘钥为123456
可以看到在堆栈中有相关秘钥的信息,且与我们之前分析的加密好的文件中那串字符串一模一样,
由此推断,这串字符串就是加密后的秘钥
分析5.jpg

我们试试修改那串秘钥字符串为自己的秘钥字符串,然后生成播放密码进行测试
分析6.jpg

然后点击播放,可以看到,已经可以绕过原有的播放密码进行播放了

分析9.jpg

然后这样虽然能正常播放,但是每次播放都要修改秘钥,而且文件还特别多,很麻烦,想试试提取

我们知道,他要播放一个视频,他必须读取原有播放文件,然后进行解密,然后才能正常播放,
所以我们从ReadFile函数入手
分析10.jpg

下面的这次读取应该就是读取加密文件了,

分析12.jpg

我们再运行一次,然后跟踪读取出来的数据

分析13.jpg

我们打开16进制编辑工具,然后进行分析,可以看到,确实是读取了加密的文件数据

分析14.jpg

我们跟踪一下调用ReadFile返回后的地方
分析15.jpg

接下来我们用IDA分析,比较方便一点,用ida前,先计算一下偏移,因为调用ReadFile函数的是一个dll,
在静态分析dll,加载的地址都是10001000
分析16.jpg

计算出偏移后,我们打开ida,定位那个调用ReadFile函数进行读取加密文件的地方,

分析17.jpg

然后,我就卡在这了,因为我也没有相关做加密解密相关的经验,这代码一看,挺蒙的,
而且还没有注释,提示什么的都没有,所以只好求助一下大家

分析19.jpg

下面这个是这个函数的交叉引用,推断是读取数据后,存入堆内存,然后交叉引用进行解密操作
交叉引用.jpg

下面就是贴代码,
代码1:调用ReadFile的函数:

[C] 纯文本查看 复制代码

unsigned int __cdecl _read_nolock(int FileHandle, LPVOID lpBuffer, DWORD nNumberOfBytesToRead)
{
  DWORD v3; // edx
  unsigned int result; // eax
  int *v5; // edi
  int v6; // eax
  int v7; // esi
  char v8; // cl
  CHAR *v9; // ebx
  int v10; // eax
  int v11; // ecx
  int v12; // edx
  int v13; // ecx
  CHAR *v14; // eax
  CHAR v15; // cl
  bool v16; // zf
  int v17; // ecx
  CHAR v18; // cl
  int v19; // ecx
  CHAR v20; // cl
  int v21; // ecx
  int v22; // eax
  char *v23; // eax
  CHAR *v24; // ebx
  CHAR v25; // al
  _BYTE *v26; // eax
  _BYTE *v27; // ebx
  int v28; // ecx
  int v29; // eax
  char v30; // dl
  _BYTE *v31; // ebx
  int v32; // ebx
  unsigned int v33; // eax
  int v34; // edx
  BOOL v35; // ecx
  CHAR *v36; // ebx
  int v37; // ecx
  _BYTE *v38; // esi
  __int16 v39; // [esp-Ch] [ebp-2Ch]
  DWORD v40; // [esp+4h] [ebp-1Ch]
  DWORD NumberOfBytesRead; // [esp+8h] [ebp-18h] BYREF
  unsigned int v42; // [esp+Ch] [ebp-14h]
  LPCCH lpMultiByteStr; // [esp+10h] [ebp-10h]
  unsigned int v44; // [esp+14h] [ebp-Ch]
  __int16 v45; // [esp+18h] [ebp-8h] BYREF
  char v46; // [esp+1Eh] [ebp-2h]
  char Buffer; // [esp+1Fh] [ebp-1h] BYREF
  LPCCH nNumberOfBytesToReada; // [esp+30h] [ebp+10h]
  LPCCH nNumberOfBytesToReadb; // [esp+30h] [ebp+10h]

  v3 = nNumberOfBytesToRead;
  v42 = -2;
  v40 = nNumberOfBytesToRead;
  if ( FileHandle == -2 )
  {
    *__doserrno() = 0;
    *_errno() = 9;
    return -1;
  }
  if ( FileHandle < 0 || FileHandle >= uNumber )
  {
    *__doserrno() = 0;
    *_errno() = 9;
    _invalid_parameter_noinfo();
    return -1;
  }
  v5 = &dword_10DEADC0[FileHandle >> 5];
  v6 = *v5;
  v7 = (FileHandle & 0x1F) << 6;
  v8 = *(_BYTE *)(*v5 + v7 + 4);
  if ( (v8 & 1) == 0 )
  {
    *__doserrno() = 0;
    *_errno() = 9;
LABEL_19:
    _invalid_parameter_noinfo();
    return -1;
  }
  if ( nNumberOfBytesToRead > 0x7FFFFFFF )
    goto LABEL_18;
  v44 = 0;
  if ( !nNumberOfBytesToRead || (v8 & 2) != 0 )
    return 0;
  if ( !lpBuffer )
    goto LABEL_18;
  v46 = (char)(2 * *(_BYTE *)(v6 + v7 + 36)) >> 1;
  if ( v46 != 1 )
  {
    if ( v46 != 2 )
    {
LABEL_16:
      v9 = (CHAR *)lpBuffer;
      lpMultiByteStr = (LPCCH)lpBuffer;
      goto LABEL_26;
    }
    if ( (nNumberOfBytesToRead & 1) == 0 )
    {
      nNumberOfBytesToRead &= 0xFFFFFFFE;
      goto LABEL_16;
    }
LABEL_18:
    *__doserrno() = 0;
    *_errno() = 22;
    goto LABEL_19;
  }
  if ( (nNumberOfBytesToRead & 1) != 0 )
    goto LABEL_18;
  nNumberOfBytesToRead = 4;
  if ( v3 >> 1 >= 4 )
    nNumberOfBytesToRead = v3 >> 1;
  v9 = (CHAR *)_malloc_crt(nNumberOfBytesToRead);
  lpMultiByteStr = v9;
  if ( !v9 )
  {
    *_errno() = 12;
    *__doserrno() = 8;
    return -1;
  }
  v10 = _lseeki64_nolock(FileHandle, 0, 0, 1u);
  v11 = *v5;
  *(_DWORD *)(v7 + v11 + 40) = v10;
  *(_DWORD *)(v7 + v11 + 44) = v12;
LABEL_26:
  v13 = v7 + *v5;
  v14 = v9;
  if ( (*(_BYTE *)(v13 + 4) & 0x48) != 0 )
  {
    v15 = *(_BYTE *)(v13 + 5);
    if ( v15 != 10 )
    {
      if ( nNumberOfBytesToRead )
      {
        --nNumberOfBytesToRead;
        v16 = v46 == 0;
        *v9 = v15;
        v17 = *v5;
        v14 = v9 + 1;
        v44 = 1;
        *(_BYTE *)(v7 + v17 + 5) = 10;
        if ( !v16 )
        {
          v18 = *(_BYTE *)(v7 + *v5 + 37);
          if ( v18 != 10 )
          {
            if ( nNumberOfBytesToRead )
            {
              *v14 = v18;
              v19 = *v5;
              v14 = v9 + 2;
              --nNumberOfBytesToRead;
              v16 = v46 == 1;
              v44 = 2;
              *(_BYTE *)(v7 + v19 + 37) = 10;
              if ( v16 )
              {
                v20 = *(_BYTE *)(v7 + *v5 + 38);
                if ( v20 != 10 )
                {
                  if ( nNumberOfBytesToRead )
                  {
                    *v14 = v20;
                    v21 = *v5;
                    v14 = v9 + 3;
                    --nNumberOfBytesToRead;
                    v44 = 3;
                    *(_BYTE *)(v7 + v21 + 38) = 10;
                  }
                }
              }
            }
          }
        }
      }
    }
  }
  if ( !ReadFile(*(HANDLE *)(v7 + *v5), v14, nNumberOfBytesToRead, &NumberOfBytesRead, 0)
    || (NumberOfBytesRead & 0x80000000) != 0
    || NumberOfBytesRead > nNumberOfBytesToRead )
  {
    v33 = GetLastError();
    if ( v33 == 5 )
    {
      *_errno() = 9;
      *__doserrno() = 5;
      goto LABEL_93;
    }
    if ( v33 == 109 )
    {
      v42 = 0;
      goto $error_return$29001;
    }
    goto LABEL_92;
  }
  v22 = *v5;
  v44 += NumberOfBytesRead;
  v23 = (char *)(v7 + v22 + 4);
  if ( *v23 < 0 )
  {
    if ( v46 != 2 )
    {
      if ( NumberOfBytesRead && *v9 == 10 )
        *v23 |= 4u;
      else
        *v23 &= 0xFBu;
      v24 = (CHAR *)lpMultiByteStr;
      nNumberOfBytesToReada = lpMultiByteStr;
      v44 += (unsigned int)lpMultiByteStr;
      if ( (unsigned int)lpMultiByteStr < v44 )
      {
        do
        {
          v25 = *nNumberOfBytesToReada;
          if ( *nNumberOfBytesToReada == 26 )
          {
            v26 = (_BYTE *)(v7 + *v5 + 4);
            if ( (*v26 & 0x40) != 0 )
              *v24++ = *nNumberOfBytesToReada;
            else
              *v26 |= 2u;
            break;
          }
          if ( v25 == 13 )
          {
            if ( (unsigned int)nNumberOfBytesToReada < v44 - 1 )
            {
              if ( nNumberOfBytesToReada[1] == 10 )
              {
                nNumberOfBytesToReada += 2;
                goto LABEL_52;
              }
              ++nNumberOfBytesToReada;
LABEL_63:
              *v24 = 13;
LABEL_64:
              ++v24;
              continue;
            }
            ++nNumberOfBytesToReada;
            if ( !ReadFile(*(HANDLE *)(v7 + *v5), &Buffer, 1u, &NumberOfBytesRead, 0) && GetLastError()
              || !NumberOfBytesRead )
            {
              goto LABEL_63;
            }
            if ( (*(_BYTE *)(v7 + *v5 + 4) & 0x48) != 0 )
            {
              if ( Buffer != 10 )
              {
                *v24 = 13;
                *(_BYTE *)(v7 + *v5 + 5) = Buffer;
                goto LABEL_64;
              }
LABEL_52:
              *v24 = 10;
              goto LABEL_64;
            }
            if ( v24 == lpMultiByteStr && Buffer == 10 )
              goto LABEL_52;
            _lseeki64_nolock(FileHandle, -1, -1, 1u);
            if ( Buffer != 10 )
              goto LABEL_63;
          }
          else
          {
            *v24++ = v25;
            ++nNumberOfBytesToReada;
          }
        }
        while ( (unsigned int)nNumberOfBytesToReada < v44 );
      }
      v44 = v24 - lpMultiByteStr;
      if ( v46 != 1 || v24 == lpMultiByteStr )
        goto $error_return$29001;
      v27 = v24 - 1;
      LOBYTE(v28) = *v27;
      if ( (char)*v27 < 0 )
      {
        v29 = 1;
        v28 = (unsigned __int8)v28;
        while ( !byte_10921C60[v28] && v29 <= 4 && v27 >= lpMultiByteStr )
        {
          v28 = (unsigned __int8)*--v27;
          ++v29;
        }
        v30 = *v27;
        if ( !byte_10921C60[(unsigned __int8)*v27] )
        {
          *_errno() = 42;
LABEL_93:
          v42 = -1;
          goto $error_return$29001;
        }
        if ( byte_10921C60[(unsigned __int8)*v27] + 1 == v29 )
        {
          v27 += v29;
        }
        else if ( (*(_BYTE *)(*v5 + v7 + 4) & 0x48) != 0 )
        {
          v31 = v27 + 1;
          *(_BYTE *)(*v5 + v7 + 5) = v30;
          if ( v29 >= 2 )
            *(_BYTE *)(v7 + *v5 + 37) = *v31++;
          if ( v29 == 3 )
            *(_BYTE *)(v7 + *v5 + 38) = *v31++;
          v27 = &v31[-v29];
        }
        else
        {
          _lseeki64_nolock(FileHandle, -v29, -v29 >> 31, 1u);
        }
      }
      else
      {
        ++v27;
      }
      v32 = v27 - lpMultiByteStr;
      v44 = MultiByteToWideChar(0xFDE9u, 0, lpMultiByteStr, v32, (LPWSTR)lpBuffer, v40 >> 1);
      if ( v44 )
      {
        v34 = *v5;
        v35 = v44 != v32;
        v44 *= 2;
        *(_DWORD *)(v7 + v34 + 48) = v35;
        goto $error_return$29001;
      }
      v33 = GetLastError();
LABEL_92:
      _dosmaperr(v33);
      goto LABEL_93;
    }
    if ( NumberOfBytesRead && *(_WORD *)v9 == 10 )
      *v23 |= 4u;
    else
      *v23 &= 0xFBu;
    v36 = (CHAR *)lpMultiByteStr;
    nNumberOfBytesToReadb = lpMultiByteStr;
    v44 += (unsigned int)lpMultiByteStr;
    if ( (unsigned int)lpMultiByteStr >= v44 )
    {
LABEL_129:
      v44 = v36 - lpMultiByteStr;
      goto $error_return$29001;
    }
    while ( 1 )
    {
      v37 = *(unsigned __int16 *)nNumberOfBytesToReadb;
      if ( v37 == 26 )
      {
        v38 = (_BYTE *)(v7 + *v5 + 4);
        if ( (*v38 & 0x40) != 0 )
        {
          *(_WORD *)v36 = *(_WORD *)nNumberOfBytesToReadb;
          v36 += 2;
        }
        else
        {
          *v38 |= 2u;
        }
        goto LABEL_129;
      }
      if ( v37 == 13 )
      {
        if ( (unsigned int)nNumberOfBytesToReadb < v44 - 2 )
        {
          if ( *((_WORD *)nNumberOfBytesToReadb + 1) == 10 )
          {
            nNumberOfBytesToReadb += 4;
            goto LABEL_110;
          }
          nNumberOfBytesToReadb += 2;
LABEL_121:
          v39 = 13;
LABEL_122:
          *(_WORD *)v36 = v39;
          goto LABEL_123;
        }
        nNumberOfBytesToReadb += 2;
        if ( !ReadFile(*(HANDLE *)(v7 + *v5), &v45, 2u, &NumberOfBytesRead, 0) && GetLastError() || !NumberOfBytesRead )
          goto LABEL_121;
        if ( (*(_BYTE *)(v7 + *v5 + 4) & 0x48) != 0 )
        {
          if ( v45 != 10 )
          {
            *(_WORD *)v36 = 13;
            *(_BYTE *)(v7 + *v5 + 5) = v45;
            *(_BYTE *)(v7 + *v5 + 37) = HIBYTE(v45);
            *(_BYTE *)(v7 + *v5 + 38) = 10;
LABEL_123:
            v36 += 2;
            goto LABEL_124;
          }
LABEL_110:
          v39 = 10;
          goto LABEL_122;
        }
        if ( v36 == lpMultiByteStr && v45 == 10 )
          goto LABEL_110;
        _lseeki64_nolock(FileHandle, -2, -1, 1u);
        if ( v45 != 10 )
          goto LABEL_121;
      }
      else
      {
        *(_WORD *)v36 = v37;
        v36 += 2;
        nNumberOfBytesToReadb += 2;
      }
LABEL_124:
      if ( (unsigned int)nNumberOfBytesToReadb >= v44 )
        goto LABEL_129;
    }
  }
$error_return$29001:
  if ( lpMultiByteStr != lpBuffer )
    free((void *)lpMultiByteStr);
  result = v42;
  if ( v42 == -2 )
    result = v44;
  return result;
}

下面是交叉引用相关函数:

[C] 纯文本查看 复制代码

int __usercall _tsopen_nolock@<eax>(int *a1@<eax>, int a2, LPCWSTR lpFileName, int a4, int a5, int a6)
{
  unsigned int v7; // eax
  int v9; // eax
  _BYTE *v10; // eax
  unsigned int v11; // eax
  DWORD v12; // eax
  _BYTE *v13; // eax
  unsigned int v14; // esi
  char v15; // cl
  _BYTE *v16; // eax
  int v17; // edi
  int v18; // eax
  DWORD v19; // eax
  DWORD v20; // eax
  int v21; // edi
  __int64 v22; // rax
  int v23; // eax
  int v24; // edx
  unsigned int v25; // eax
  __int64 v26; // rax
  int v27; // eax
  int v28; // edx
  int v29; // eax
  int v30; // ebx
  int v31; // eax
  _BYTE *v32; // eax
  _BYTE *v33; // eax
  bool v34; // zf
  _BYTE *v35; // eax
  HANDLE v36; // eax
  unsigned int v37; // eax
  _BYTE *v38; // eax
  DWORD v39; // [esp-Ch] [ebp-48h]
  int v40; // [esp-8h] [ebp-44h]
  struct _SECURITY_ATTRIBUTES SecurityAttributes; // [esp+8h] [ebp-34h] BYREF
  int Buffer; // [esp+14h] [ebp-28h] BYREF
  int v43; // [esp+18h] [ebp-24h] BYREF
  HANDLE hFile; // [esp+1Ch] [ebp-20h]
  int Buf; // [esp+20h] [ebp-1Ch] BYREF
  DWORD dwCreationDisposition; // [esp+24h] [ebp-18h]
  DWORD dwShareMode; // [esp+28h] [ebp-14h]
  DWORD dwFlagsAndAttributes; // [esp+2Ch] [ebp-10h]
  DWORD dwDesiredAccess; // [esp+30h] [ebp-Ch]
  int v50; // [esp+34h] [ebp-8h]
  char v51; // [esp+39h] [ebp-3h]
  char v52; // [esp+3Ah] [ebp-2h]
  char v53; // [esp+3Bh] [ebp-1h]

  v43 = 0;
  v52 = 0;
  v50 = 0;
  SecurityAttributes.nLength = 12;
  SecurityAttributes.lpSecurityDescriptor = 0;
  if ( (a4 & 0x80u) == 0 )
  {
    SecurityAttributes.bInheritHandle = 1;
    v53 = 0;
  }
  else
  {
    SecurityAttributes.bInheritHandle = 0;
    v53 = 16;
  }
  if ( sub_106CE235(&v43) )
    _invoke_watson(0, 0, 0, 0, 0);
  if ( (a4 & 0x8000) == 0 && ((a4 & 0x74000) != 0 || v43 != 0x8000) )
    v53 |= 0x80u;
  if ( (a4 & 3) != 0 )
  {
    if ( (a4 & 3) != 1 )
    {
      if ( (a4 & 3) != 2 )
        goto LABEL_40;
      goto LABEL_13;
    }
    if ( (a4 & 8) != 0 && (a4 & 0x70000) != 0 )
    {
LABEL_13:
      dwDesiredAccess = -1073741824;
      goto LABEL_18;
    }
    dwDesiredAccess = 0x40000000;
  }
  else
  {
    dwDesiredAccess = 0x80000000;
  }
LABEL_18:
  switch ( a5 )
  {
    case 16:
      dwShareMode = 0;
      break;
    case 32:
      dwShareMode = 1;
      break;
    case 48:
      dwShareMode = 2;
      break;
    case 64:
      dwShareMode = 3;
      break;
    case 128:
      dwShareMode = dwDesiredAccess == 0x80000000;
      break;
    default:
      goto LABEL_40;
  }
  v7 = a4 & 0x700;
  if ( v7 > 0x400 )
  {
    if ( v7 != 1280 )
    {
      if ( v7 == 1536 )
        goto LABEL_41;
      if ( v7 != 1792 )
        goto LABEL_40;
    }
    dwCreationDisposition = 1;
    goto LABEL_43;
  }
  if ( (a4 & 0x700) == 1024 || (a4 & 0x700) == 0 )
  {
    dwCreationDisposition = 3;
    goto LABEL_43;
  }
  if ( v7 == 256 )
  {
    dwCreationDisposition = 4;
    goto LABEL_43;
  }
  if ( v7 == 512 )
  {
LABEL_41:
    dwCreationDisposition = 5;
    goto LABEL_43;
  }
  if ( v7 != 768 )
  {
LABEL_40:
    *__doserrno() = 0;
    *a1 = -1;
    *_errno() = 22;
    _invalid_parameter_noinfo();
    return 22;
  }
  dwCreationDisposition = 2;
LABEL_43:
  dwFlagsAndAttributes = 128;
  if ( (a4 & 0x100) != 0 && (a6 & ~(_BYTE)dword_10D4CDFC & 0x80u) == 0 )
    dwFlagsAndAttributes = 1;
  if ( (a4 & 0x40) != 0 )
  {
    dwFlagsAndAttributes |= 0x4000000u;
    dwDesiredAccess |= 0x10000u;
    dwShareMode |= 4u;
  }
  if ( (a4 & 0x1000) != 0 )
    dwFlagsAndAttributes |= 0x100u;
  if ( (a4 & 0x20) != 0 )
  {
    dwFlagsAndAttributes |= 0x8000000u;
  }
  else if ( (a4 & 0x10) != 0 )
  {
    dwFlagsAndAttributes |= (unsigned int)&_ImageBase;
  }
  v9 = _alloc_osfhnd();
  *a1 = v9;
  if ( v9 == -1 )
  {
    *__doserrno() = 0;
    *a1 = -1;
    *_errno() = 24;
    return *_errno();
  }
  v39 = dwFlagsAndAttributes;
  *(_DWORD *)a2 = 1;
  hFile = CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, &SecurityAttributes, dwCreationDisposition, v39, 0);
  if ( hFile != (HANDLE)-1
    || (dwDesiredAccess & 0xC0000000) == -1073741824
    && (a4 & 1) != 0
    && (dwDesiredAccess &= 0x7FFFFFFFu,
        hFile = CreateFileW(
                  lpFileName,
                  dwDesiredAccess,
                  dwShareMode,
                  &SecurityAttributes,
                  dwCreationDisposition,
                  dwFlagsAndAttributes,
                  0),
        hFile != (HANDLE)-1) )
  {
    v12 = GetFileType(hFile);
    switch ( v12 )
    {
      case 0u:
        v13 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 4);
        *v13 &= 0xFEu;
        v14 = GetLastError();
        _dosmaperr(v14);
        CloseHandle(hFile);
        if ( !v14 )
          *_errno() = 13;
        return *_errno();
      case 2u:
        v53 |= 0x40u;
        break;
      case 3u:
        v53 |= 8u;
        break;
    }
    _set_osfhnd(*a1, hFile);
    v15 = v53 | 1;
    *(_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 4) = v53 | 1;
    v16 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 36);
    *v16 &= 0x80u;
    v51 = v15 & 0x48;
    v53 = v15;
    if ( (v15 & 0x48) == 0 )
    {
      if ( v15 >= 0 )
        goto LABEL_131;
      if ( (a4 & 2) != 0 )
      {
        v17 = _lseek_nolock(*a1, -1, 2u);
        if ( v17 == -1 )
        {
          if ( *__doserrno() != 131 )
          {
LABEL_74:
            _close_nolock(*a1);
            return *_errno();
          }
        }
        else
        {
          Buffer = 0;
          if ( !_read_nolock(*a1, &Buffer, 1u) && (_WORD)Buffer == 26 && _chsize_nolock(*a1, v17, v17 >> 31) == -1
            || _lseek_nolock(*a1, 0, 0) == -1 )
          {
            goto LABEL_74;
          }
        }
      }
    }
    if ( v53 >= 0 )
    {
LABEL_131:
      v32 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 36);
      *v32 ^= (v52 ^ *v32) & 0x7F;
      v33 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 36);
      v34 = v51 == 0;
      *v33 = *v33 & 0x7F | (BYTE2(a4) << 7);
      if ( v34 && (a4 & 8) != 0 )
      {
        v35 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 4);
        *v35 |= 0x20u;
      }
      if ( (dwDesiredAccess & 0xC0000000) != -1073741824 || (a4 & 1) == 0 )
        return v50;
      CloseHandle(hFile);
      v36 = CreateFileW(
              lpFileName,
              dwDesiredAccess & 0x7FFFFFFF,
              dwShareMode,
              &SecurityAttributes,
              3u,
              dwFlagsAndAttributes,
              0);
      if ( v36 != (HANDLE)-1 )
      {
        *(_DWORD *)(((*a1 & 0x1F) << 6) + dword_10DEADC0[*a1 >> 5]) = v36;
        return v50;
      }
      v37 = GetLastError();
      _dosmaperr(v37);
      v38 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 4);
      *v38 &= 0xFEu;
      _free_osfhnd(*a1);
      return *_errno();
    }
    if ( (a4 & 0x74000) == 0 )
    {
      if ( (v43 & 0x74000) != 0 )
        a4 |= v43 & 0x74000;
      else
        a4 |= 0x4000u;
    }
    v18 = a4 & 0x74000;
    if ( (a4 & 0x74000) == 0x4000 )
    {
      v52 = 0;
      goto LABEL_95;
    }
    if ( v18 == 0x10000 || v18 == 81920 )
    {
      if ( (a4 & 0x301) != 769 )
        goto LABEL_95;
    }
    else if ( v18 != 0x20000 && v18 != 147456 )
    {
      if ( v18 == 0x40000 || v18 == 278528 )
        v52 = 1;
LABEL_95:
      if ( (a4 & 0x70000) == 0 )
        goto LABEL_131;
      Buf = 0;
      if ( (v53 & 0x40) != 0 )
        goto LABEL_131;
      v19 = dwDesiredAccess & 0xC0000000;
      if ( (dwDesiredAccess & 0xC0000000) == 0x40000000 )
      {
        v20 = dwCreationDisposition;
        if ( !dwCreationDisposition )
          goto LABEL_131;
        if ( dwCreationDisposition <= 2 )
          goto LABEL_104;
        if ( dwCreationDisposition > 4 )
          goto LABEL_103;
        LODWORD(v26) = _lseeki64_nolock(*a1, 0, 0, 2u);
        if ( v26 )
        {
          v27 = _lseeki64_nolock(*a1, 0, 0, 0);
          v29 = v28 & v27;
          goto LABEL_119;
        }
      }
      else
      {
        if ( v19 == 0x80000000 )
          goto LABEL_109;
        if ( v19 != -1073741824 )
          goto LABEL_131;
        v20 = dwCreationDisposition;
        if ( !dwCreationDisposition )
          goto LABEL_131;
        if ( dwCreationDisposition > 2 )
        {
          if ( dwCreationDisposition > 4 )
          {
LABEL_103:
            if ( v20 != 5 )
              goto LABEL_131;
            goto LABEL_104;
          }
          LODWORD(v22) = _lseeki64_nolock(*a1, 0, 0, 2u);
          if ( v22 )
          {
            v23 = _lseeki64_nolock(*a1, 0, 0, 0);
            if ( (v24 & v23) == -1 )
              goto LABEL_74;
LABEL_109:
            v25 = _read_nolock(*a1, &Buf, 3u);
            if ( v25 == -1 )
              goto LABEL_74;
            if ( v25 != 2 )
            {
              if ( v25 != 3 )
              {
LABEL_126:
                v29 = _lseek_nolock(*a1, 0, 0);
LABEL_119:
                if ( v29 == -1 )
                  goto LABEL_74;
                goto LABEL_131;
              }
              if ( Buf == 12565487 )
              {
                v52 = 1;
                goto LABEL_131;
              }
            }
            if ( (unsigned __int16)Buf == 65534 )
            {
              _close_nolock(*a1);
              *_errno() = 22;
              return 22;
            }
            if ( (unsigned __int16)Buf == 65279 )
            {
              if ( _lseek_nolock(*a1, 2, 0) == -1 )
                goto LABEL_74;
              v52 = 2;
              goto LABEL_131;
            }
            goto LABEL_126;
          }
        }
      }
LABEL_104:
      v21 = 0;
      if ( v52 == 1 )
      {
        Buf = 12565487;
        v40 = 3;
LABEL_128:
        v30 = v40;
        while ( 1 )
        {
          v31 = _write(*a1, (char *)&Buf + v21, v30 - v21);
          if ( v31 == -1 )
            goto LABEL_74;
          v21 += v31;
          if ( v30 <= v21 )
            goto LABEL_131;
        }
      }
      if ( v52 == 2 )
      {
        Buf = 65279;
        v40 = 2;
        goto LABEL_128;
      }
      goto LABEL_131;
    }
    v52 = 2;
    goto LABEL_95;
  }
  v10 = (_BYTE *)(dword_10DEADC0[*a1 >> 5] + ((*a1 & 0x1F) << 6) + 4);
  *v10 &= 0xFEu;
  v11 = GetLastError();
  _dosmaperr(v11);
  return *_errno();
}

下面这个应该不是:
不过也是交叉引用了那个ReadFile的函数

[C] 纯文本查看 复制代码

int __cdecl _read(int FileHandle, void *DstBuf, unsigned int MaxCharCount)
{
  int *v4; // edi
  int v5; // esi
  int v6; // [esp+14h] [ebp-1Ch]

  if ( FileHandle == -2 )
  {
    *__doserrno() = 0;
    *_errno() = 9;
    return -1;
  }
  if ( FileHandle < 0
    || FileHandle >= uNumber
    || (v4 = &dword_10DEADC0[FileHandle >> 5], v5 = (FileHandle & 0x1F) << 6, (*(_BYTE *)(*v4 + v5 + 4) & 1) == 0) )
  {
    *__doserrno() = 0;
    *_errno() = 9;
LABEL_7:
    _invalid_parameter_noinfo();
    return -1;
  }
  if ( MaxCharCount > 0x7FFFFFFF )
  {
    *__doserrno() = 0;
    *_errno() = 22;
    goto LABEL_7;
  }
  __lock_fhandle(FileHandle);
  if ( (*(_BYTE *)(*v4 + v5 + 4) & 1) != 0 )
  {
    v6 = _read_nolock(FileHandle, DstBuf, MaxCharCount);
  }
  else
  {
    *_errno() = 9;
    *__doserrno() = 0;
    v6 = -1;
  }
  _unlock_fhandle(FileHandle);
  return v6;
}

hpp0hpp · 发表于 2021-7-24 22:56

你试试修改解密播放器代码,让播放器自动把假码替换成真码并解密.

帐号		自动登录	找回密码
密码			注册[Register]

[求助] ida分析readFile相关函数遇到问题

免费评分