Question

unsigned char* Data::getAddress(unsigned char* address)
{
    strcpy((char*)address, (char*)this->_address);
    return (unsigned char*)address;
}

int main()
{
    Data d;
    d.makealinkedlisthere();
    while (d)
    {
       unsigned char address[256];
       printf("0x%08x \r\n",d.getAddress(address));
       d = d.getNext();
    }
    return 0;
}

它返回前两个（它们是相同的，它应该是不同的[可以从调试器中告诉] ...）然后崩溃。

它只是制作一个链表。受保护的成员Data* _next ......它们的链条。

unsigned char *来自Windows函数VirtualQueryEx它返回的MEMORY_BASIC_INFORMATION数据结构的一部分。

this->_address = (unsigned char*)meminfo->BaseAddress; // casted from void*

它是无效*，但我看到它在其他代码中转换为unsigned char *。在调试器中，我可以看到它表示为十六进制数字。

D1: +    _address   0x7ffd5000 <Bad Ptr>    unsigned char * 
D1->_next:+  _address   0x7f6f0000 "áå•ú`©" unsigned char * 
D1->_next->_next+    _address   0x7ffb0000 " "  unsigned char *

Answer 1

MEMORY_BASIC_INFORMATION.Base地址是页面区域的位置而不是字符串，并且没有保证它将被终止。在MSDN网站上，您可以看到MEMORY_BASIC_INFORMATION structure

typedef struct _MEMORY_BASIC_INFORMATION {
  PVOID  BaseAddress;
  PVOID  AllocationBase;
  DWORD  AllocationProtect;
  SIZE_T RegionSize;
  DWORD  State;
  DWORD  Protect;
  DWORD  Type;
} MEMORY_BASIC_INFORMATION, *PMEMORY_BASIC_INFORMATION;

要复制数据，您应使用大小= 255的memcpy。

回顾您的代码，前提是没有其他问题，请将其更改为

PVOID Data::getAddress(PVOID address,size) {    
    memcpy((address, (void *)this->_address, size);
    address[size]=NULL;
    return address;
}
int main() {
    Data d;
    d.makealinkedlisthere();
    while (d) {
       unsigned char address[256];
       printf("Address: 0x%08x \n",d.getAddress((PVOID)address),sizeof(address));
       printf("Data: %s\n",(LPSTR)d.getAddress((PVOID)address),sizeof(address));
       d = d.getNext();
    }
    return 0;
}

应该有效

请注意，存储RegionSize并在memcpy之前进行边界检查是安全的。

C / C ++ strcpy未处理的读取违规

1 个答案: