can not query values from windows registry - c++

Question

I writing program for the Windows registry and trying to query values from it, but even if I running my own program with the permissions of Administrator, I can not read all parameters and got error code 5 - Access Denied for some values. But at the same time standard regedit could show me that value. What did i doing wrong?
I have a class for the registry RegistryClass
RegistryClass.h:
class RegistryClass
{
HKEY hKey;
public:
int GetCountOfKeys();
bool OpenKey(HKEY key, std::string path);
void EnumKeys(char ** result, int * count);
...
}
RegistryClass.cpp
#include "RegistryClass.h"
...
bool RegistryClass::OpenKey(HKEY key, std::string path)
{
if(RegOpenKeyExA(key,path.c_str(),NULL,KEY_ALL_ACCESS,&hKey) == ERROR_SUCCESS)
{
return true;
}
hKey = NULL;
return false;
}
int RegistryClass::GetCountOfKeys()
{
DWORD count = 0;
char keyName [256];
DWORD len = 255;
while(1)
{
if(RegEnumKeyExA(hKey,count,keyName,&len,NULL,NULL,NULL,NULL) != ERROR_SUCCESS)
break;
count++;
len = 255;
}
return count;
}
void RegistryClass::EnumKeys(char ** result, int * count)
{
if(hKey == NULL)
return;
*count = 0;
DWORD dwIndex = 0; // current key
char keyName [255]; // current key name
DWORD lpcchName = 255; // name length
int error;
do
{
error = RegEnumKeyExA(hKey,dwIndex,keyName,&lpcchName,NULL,NULL,NULL,NULL);
if(error == ERROR_SUCCESS)
{
memcpy(result[(*count)],keyName,lpcchName);
(*count)++;
}
dwIndex++;
lpcchName = 255;
}while(error == ERROR_SUCCESS);
}
in main program i trying to retrive keys
void MainWindow::InitializeFirstState()
{
item_HKEY_CLASSES_ROOT = new QTreeWidgetItem();
item_HKEY_CLASSES_ROOT->setText(0,"HKEY_CLASSES_ROOT");
// and other keys
...
tree->addTopLevelItem(item_HKEY_CLASSES_ROOT);
...
AddInternalKeys(item_HKEY_CLASSES_ROOT,true);
...
}
...
void AddInternalKeys(QTreeWidgetItem * item, bool rec)
{
std::string currentPath = GetFullPathKey(item);
// first key name
std::string keyName = GetParentKeyName(item);
RegistryClass * regC = new RegistryClass();
HKEY key;
if(strcmp(keyName.c_str(),"HKEY_CLASSES_ROOT") == 0)
{
key = HKEY_CLASSES_ROOT;
}
else if(strcmp(keyName.c_str(),"HKEY_CURRENT_USER") == 0)
{
key = HKEY_CURRENT_USER;
}
else if(strcmp(keyName.c_str(),"HKEY_LOCAL_MACHINE") == 0)
{
key = HKEY_LOCAL_MACHINE;
}
else if(strcmp(keyName.c_str(),"HKEY_USERS") == 0)
{
key = HKEY_USERS;
}
else // HKEY_CURRENT_CONFIG
{
key = HKEY_CURRENT_CONFIG;
}
if(regC->OpenKey(key,currentPath) == true)
{
internalLog->print("key opened succesfully\n");
}
else internalLog->print("key was not opened\n");
int count = regC->GetCountOfKeys();
char ** keys = (char **) malloc(sizeof(char *) * count);
for(int i=0;i<count;i++)
{
keys[i] = (char *) malloc(sizeof(char) * 256);
memset(keys[i],0,sizeof(char) * 256);
}
regC->EnumKeys(keys,&count);
regC->CloseKey();
delete regC;
QTreeWidgetItem * newItem;
count--;
while(count >= 0)
{
newItem = new QTreeWidgetItem();
newItem->setText(0,keys[count]);
item->addChild(newItem);
std::string str = keys[count];
AddKeyNames(newItem,str);
free(keys[count]);
if(rec == true)
AddInternalKeys(newItem,false);
count--;
}
free(keys);
}

Answer 1

You are asking for too much access. You are asking for KEY_ALL_ACCESS when all you actually need is KEY_READ. You do not have all-access permission, but you do have read permission.