我怎么能将char转换为字符串C ++（读取内存） [英] How could I convert a char to a string C++ (read memory)

问题描述

我正在尝试从我使用内核驱动程序与我的usermode应用程序通信的虚拟程序中读取字符串。我已经这样做了这个



void * response //读取响应或发送给我的驱动程序所以它读取它

所以我正在使用模板来读取它的内存

 模板< typename T> 
 T read（UINT_PTR ProcessId，UINT_PTR ReadAddress，SIZE_T Size）
 {
  if （hDriver == INVALID_HANDLE_VALUE）
  return （T） false ; 
 
 DWORD返回，字节; 
 KERNEL_READ_REQUEST ReadRequest; 
 
 ReadRequest.ProcessId = ProcessId; 
 ReadRequest.Address = ReadAddress; 
 ReadRequest.Size =大小？大小： sizeof （T）; 
 
  //  使用参数将代码发送到我们的驱动程序 
  if （DeviceIoControl（hDriver，IO_READ_REQUEST，& ReadRequest，
  sizeof （ReadRequest））& ; ReadRequest， sizeof （ReadRequest）， 0 ， 0 ））
  return （T）ReadRequest.Response; 
  else  
  return   false < /跨度>; 
} 

所以你可以看到return（T）ReadRequest.Response;它现在在我的代码中将值返回给驱动程序我试图将char转换为这样的字符串，但它没有向我显示我想要读取的字符串的整个字符串是DefaultString但是它读取它就像找到的String：DefaultS $任何帮助将不胜感激，顺便说一下，我正在努力学习驾驶员注意事项：教育目的



我尝试过的事情：

  char  * p = Driver.read< char *>（processid，0x2A1575F818，  sizeof （p））; 
  const   char  * add = reinterpret_cast< const 炭 * GT;（&安培; p）; 
 std :: string str = add; 
 printf（ 找到的字符串：％s \ n，str.c_str（） ）; 

解决方案

任何帮助将不胜感激，并且我正在尝试了解驾驶员注意事项：教育目的



我尝试了什么：

  char  * p = Driver.read< char *>（processid，0x2A1575F818， sizeof （p））; 
  const   char  * add = reinterpret_cast< const 炭 * GT;（&安培; p）; 
 std :: string str = add; 
 printf（ 找到的字符串：％s \ n，str.c_str（） ）; 

你读的字符太少（即 sizeof（p），可能是 8 ）。

先生。帕利尼走在正确的轨道上。你的代码有这个：

 ReadRequest.Size = Size？尺寸：sizeof（T）; 
 

，这是问题的sizeof（T）语句。您可以通过至少两种方式解决此问题。一种是调整驱动程序，因此如果传递的大小为零，它将返回字符串实际具有的字节数，然后您确切地请求该数量。有一些Windows API函数以这种方式工作。另一种方法是定义最大大小，并确保您的文本缓冲区至少是那么大。无论哪种方式，您都需要将文本缓冲区的大小传递给驱动程序，而不仅仅是指针的大小。下面是一个示例：

 char * p = Driver.read< char *>（processid，0x2A1575F818,255）; 

我选择了255作为大文本缓冲区大小。在驱动程序中，大小应该被视为最大值，就像调用strncpy一样。它应该只复制文本，直到找到null。

am trying to read a string from a dummy program that i have made am using a kernel driver to communicate with my usermode app. i have made it like this

void* response // to read the response or to send it to my driver so it reads it
so am using a template to read memory its this

template <typename T>
T read(UINT_PTR ProcessId, UINT_PTR ReadAddress,SIZE_T Size)
{
    if (hDriver == INVALID_HANDLE_VALUE)
        return (T)false;

    DWORD Return, Bytes;
    KERNEL_READ_REQUEST ReadRequest;

    ReadRequest.ProcessId = ProcessId;
    ReadRequest.Address = ReadAddress;
    ReadRequest.Size = Size ? Size : sizeof(T);

    // send code to our driver with the arguments
    if (DeviceIoControl(hDriver, IO_READ_REQUEST, &ReadRequest,
        sizeof(ReadRequest), &ReadRequest, sizeof(ReadRequest), 0, 0))
        return (T)ReadRequest.Response;
    else
        return false;
}

so as you can see return (T)ReadRequest.Response; it returns the value to the driver now in my code am trying to convert a char to a string like this but it does not shows me the whole string the string i want to read is DefaultString but it reads it like this String found: DefaultS$ any help would be appreciated and btw am trying to learn about drivers note : Educational Purposes

What I have tried:

char* p = Driver.read<char*>(processid, 0x2A1575F818, sizeof(p));
const char* add = reinterpret_cast<const char*>(&p);
std::string str = add;
printf("String found: %s\n", str.c_str());

解决方案

any help would be appreciated and btw am trying to learn about drivers note : Educational Purposes

What I have tried:

char* p = Driver.read<char*>(processid, 0x2A1575F818, sizeof(p));
const char* add = reinterpret_cast<const char*>(&p);
std::string str = add;
printf("String found: %s\n", str.c_str());

You are reading too few characters (namely sizeof(p) that is, probably, 8).

Mr. Pallini is on the right track. Your code has this :

ReadRequest.Size = Size ? Size : sizeof(T);

and it is the sizeof(T) statement that is the problem. You can fix this in at least two ways. One is to adjust the driver so if it is passed a size of zero it will return how many bytes the string actually has and then you request exactly that amount. There are a few Windows API functions that work this way. The other way is to define a maximum size and make sure your text buffer is at least that big. Either way, you need to pass the size of a text buffer to the driver, not just the size of the pointer. Here is an example:

char* p = Driver.read<char*>( processid, 0x2A1575F818, 255 );

I picked 255 as a big text buffer size. In the driver, the size should be considered a maximum like in a call to strncpy. It should probably only copy text until it finds the null.

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