I'm writing a program that edits the registry using c#
I would like to check if the user has access to edit when the program loads. What is the best way to check in c#?
Each node in the registry has its own ACL (Access Credential List). There is not a single right.
Commonly, each application will have its own registry node, either in the HKLM hive or in HKCU hive, or a combination of both.
In the former case, the user has to be administrator of the computer, in the latter the user can read/write its own registry.
To check the actual access permission, you can use the RegistryKey.GetAccessControl method.
However, as stated, you have to have at least the Read permissions to call this method.
Try to open a RegistryKey with write access. If it gives you an Exception, you don't have permission.
You could probably even specifiy which Exception to a certain one which says you don't have permission.
try{
Registry.CurrentUser.OpenSubKey(#"PATH\TO\STUFF", true);
// Have write permissions.
}
catch {
// Do not have write permissions.
}
A user shouldn't have access to edit "the full registry" they should only have permissions to edit certain keys within the registry.
You would be best doing a try catch system
try{
// Do registry edit
}
catch {
Console.Log("Sorry you don't have permission to edit this key");
}
Each user is different and can have access to some parts, all parts or no parts of the registry using the windows ACL.
Have a peek at the first answer here.
Related
I want to move/copy a file into a folder on a different machine, and I want to check if the user has sufficient permissions to do this. How can I do this, where do I start? Is it even possible in C#?
There is System.Security.FileIOPermission-class that exposes methods to check on permissions.
Example from MSDN
FileIOPermission f2 = new FileIOPermission(FileIOPermissionAccess.Read, "C:\\test_r");
f2.AddPathList(FileIOPermissionAccess.Write | FileIOPermissionAccess.Read, "C:\\example\\out.txt");
try
{
f2.Demand();
}
catch (SecurityException s)
{
Console.WriteLine(s.Message);
}
You pass a file/directory to the constructor and add additional files/directories using AddPathList. Then you check if access can be granted using Demand()-method. If the caller has insufficient rights, a SecurityException is thrown.
See here.
Check article on code project which is about the thing you need
access rights for a given file
Hope it helps.
I have searched for quite a while on a solution to this. At least I think I understand the problem, but I have yet to come to any solution.
What I need is either some sort of executable or a script that will delete some registry entries. The problem is that the registry entries in question only give read/write access to SYSTEM and no one else. The only way that I can delete them is by going into regedit, setting myself as the owner, and finally setting full control to everyone. Only then can the keys be deleted. I need this process to be in some sort of script though!
So in C#, I first make sure that the software has administrative rights. Then I try to execute the following.
RegistryKey reg_localmachine = RegistryKey.OpenRemoteBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, "");
RegistryKey key = reg_localmachine.OpenSubKey(#"SYSTEM\path to subkey", true);
On the second line, when I try to access the sub key with write access, I get the exception "Requested registry access is not allowed." In order for me to change owner or grant permissions, I need to execute SetAccessControl() on the RegistryKey. In order to set access control, I need write privileges for the key. So I am in this paradox.
Security is there for a reason.
You don't want any old program to be able to come in and start hacking around in the registry.
Each entry in the registry has it's own set of DACLS. There are only two solutions:-
Change the account under which your program is running to an account that has permission to delete the registry entry.
Change the DACLS on the registry entry to include the account your program is running under.
I had asked about this in some other thread and got the link to access remote registry. But the problem I am now facing is I am not able to add any values in to registry. I was trying to add some values to an existing entry in a registry by using following code but not doing anything in remote registry:
RegistryKey rk;
rk = RegistryKey.OpenRemoteBaseKey(
RegistryHive.CurrentUser, ReadServerName());
regkey = rk.OpenSubKey(LeafRegistry.LeafRoot + "\\sim\\NewView\\");
regkey.SetValue("runsystem", SIMserver);
UPDATE
RegistryHive.LocalMachine will work here, I can open and do all operation, but then why for RegistryHive.CurrentUser ? What I am saying is in the above code I will get value for 'rk' but I cannot get value for regkey which will become null, I think for CurrentUser OpenSubKey is not working.
UPDATE
When I analyzed in depth, I saw for except this particular key, all other keys are accessible. I am wondering what is going on for this specific key, I checked permission also after right clicking, but couldn't see it?
You will almost certainly require permissions in most cases when you are attempting to change registry values on remote machines across a network. Also, in a lot of cases, even where you can amend the registry values they can be refreshed via Group Policies and reverted back.
It could be that there are certain parts of the registry that you are restricted from editing,
If you don't have administrator privelages then I think you will come unstuck.
This is not going to work. Suppose the user account your program is accessing remote machine under is not logged in on the remote machine. What should Windows do? Actually, documentation for RegConnectRegistry, which is what OpenRemoteBaseKey calls internally, does not even list HKEY_CURRENT_USER as a permissible argument.
I want set default icon of some extension by C#. But this gives me error -> Security Exception was unhandled
RegistryKey FileExt = Registry.LocalMachine.OpenSubKey("SOFTWARE\\Classes", RegistryKeyPermissionCheck.ReadWriteSubTree);
How can I do that?
try to run your application as administrator.
Maybe the user you are using to log in on the machine does not have privileged to access or modify the registry. try run the code with administrator account and see what happens. also if there is no user logged in the same error maybe occurs for instance check this.
I presume this is on Windows Vista or 7.
You may need to have elevated privileges to change some values in the registry. Even a user with administrative privileges will get the UAC pop up to ask permission before a program can do this.
Have a look at a question about this.
Here is a codeproject article about gaining elevated privileges.
try this method instead of yours:
public RegistryKey OpenSubKey(
string name,
bool writable
)
Maybe a true is enough ;-)
Registry.LocalMachine.OpenSubKey("SOFTWARE\\Classes", true);
I am trying to delete the excel file from a specipic location . but can't deleting. having error :
Access to the path 'C:\mypath\sample.xlsx' is denied.
I write a code as :
protected void imgbtnImport_Click(object sender, ImageClickEventArgs e)
{
try
{
string strApplicationPath = HttpContext.Current.Request.MapPath(HttpContext.Current.Request.ApplicationPath);
string strXLStoredDirectoryPath = strApplicationPath + "/Information Documents/";
DirectoryInfo di = new DirectoryInfo(strXLStoredDirectoryPath);
string fileName = flUpldSelectFile.FileName;
if (!File.Exists(strXLStoredDirectoryPath))
{
Directory.CreateDirectory(strXLStoredDirectoryPath);
di.Attributes = FileAttributes.Normal;
}
string strCreateXLFileDestinationPath = strXLStoredDirectoryPath + fileName;
if (File.Exists(strCreateXLFileDestinationPath))
{
File.Delete(strCreateXLFileDestinationPath);
}
flUpldSelectFile.SaveAs(strCreateXLFileDestinationPath);
di.Attributes = FileAttributes.ReadOnly;
}
catch (Exception)
{
throw;
}
}
please guide.........
-***********************************************************************
Still problem there . it is not resolved . getting UnauthorizedAccessException. as access denied to deleting file. I m tired now . please help; I tried many things..please help
-***********************************************************************
Is may be iffect of VSS ? i am using that
UPDATE:
Part of your issue might be what is saving/creating this file. If you're using a built in "Save" or "SaveAs" feature the underlying file stream might still have a lock on the file. writing your own save logic with a FileStream wrapped in a Using statement will help dispose the stream right when you're done thus allowing you to further manipulate the file within the same context.
if flUpldSelectFile.SaveAs(strCreateXLFileDestinationPath); is the only logic that saves the file then get rid of the built in SaveAs functionality. write your own save logic using a FileStream wrapped in a Using block.
In your example i can't see what flUpldSelectFile is so i am assuming it is a System.Web.UI.WebControls.FileUpload control. Here is an example of rolling your own save logic.
using (FileStream fs = new FileStream(strCreateXLFileDestinationPath, FileMode.Create))
{
byte[] buffer = flUpldSelectFile.FileBytes;
fs.Write(buffer, 0, buffer.Length);
}
As stated previously, use this tool to find out if there is a lock on the file by another process.
ORIGINAL
Pop open this wonderful tool and search for that file to see who/what has it locked
http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
(source: microsoft.com)
If your code is working under IIS , Note that ASPNET user doesn't have access to computer files, you should give access to it, that is not recommended, or store you files in the place where ASPNET user have access
see here
Try a combination of these 2 steps:
Set the IIS application pool to run under an account with privileges such as a domain account or local user account (not a default account like local service or local system). Instructions for IIS7.
Turn impersonation on in the web.config file, in the <system.web> section:
<identity impersonate="true"/>
<identity impersonate="true" userName="contoso\Jane" password="password"/>
I think the message is clear, you do not have authorization to delete the file or it is opened by another application. I bet 2$ you can't delete the file manually either.
As others have said, this is because IIS runs your application as a user with restricted access rights. This is a wise security precaution, so that your system is less vulnerable to malicious attacks.
What you need to do is to give the ASPNET user access to the specific folder. You do that from the security tab in the properties of a folder. The user you need to give full control to depends on the version of IIS you are using. In Windows XP it is ASPNET. In Windows Server 2003, 2008 and Windows Vista, 7 it is NETWORK_SERVICE.
See also this question for more details.
Make sure the file isn't opened or
locked by another user/process.
Make sure ASPNET user has access on the file\folder (check the file\folder's property using windows explorer and go to security tab. check if ASPNET user is added there).
One of two things are happening. Either the file is already open, or the permission of the user running IIS does not have the proper permissions.
Either way, this utility ProcMon: Proc Mon
will help you determine the issue. Run ProcMon, kick off your process to try and delete the file. Then go back to procmon. Hit Ctrl-E to turn off the capture, then Ctrl-F to find. Enter the name of the file you're trying to delete. Then once you've found the correct line with the access denied (or similar error) Double click on the the line to get further information. When you click on the Process tab, it will show you the exact user that is trying to delete the file.
So, if it is a file permission issue, you now know the exact user, and can therefore go to the file system right click on the folder that houses the file you are trying to delete, and grant that user permissions to read/write/update that folder.
Second, if the file is locked open instead of a permissions issue, you will have to find out what process is holding open the file. If you are also writing this file in another part of your code, perhaps you are not closing it properly or releasing the object reference.
Have you verified that the file does not have the read-only attribute set?
I don't think we have enough info to be helpful. What is the security context (identity) during the call to Delete? Is the application impersonating the end user? If it is, how are they authenticated? If by Windows / Active Directory, then you'll need to verify that user's access rights to the specific file. If by Forms login, then you should probably not impersonate and verify that the AppPool's security context has the appropriate access rights.