"Access to the path ... is denied" (.NET C#) - c#

I've been saving a small XML data file to an external drive, no probs. But then I tried to use the ApplicationData folder and others, even C:\ but no luck. I'm getting an error like "Access to the path "C:\" denied".
Just to confirm, the file is created and read fine with the current code, to an external drive. I guess this is something to do with security & permissions but I haven't found anything too useful.
Thanks in advance if you can point me in the right direction on this one!
string fipData = #"F:\IL2\SIIYM\SIIYM Data.xml"; // external drive ok :-)
//string fipData = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
//string fipData = #"C:\";
// if the XML data file doesn't exist, create it
bool dataFileExists = File.Exists(fipData);
if (dataFileExists)
{
// read the XML values
XDocument xData = XDocument.Load(fipData);
//...
}
else
{
// create & save the XML data file
XElement xLastPath = new XElement(el_lastPath, "");
XElement xLastCode = new XElement(el_lastCode, "");
XElement xRoot = new XElement(el_root);
xRoot.Add(xLastPath);
xRoot.Add(xLastCode);
XDocument newDataFile = new XDocument();
newDataFile.Add(xRoot);
try
{
newDataFile.Save(fipData);
}
catch (Exception ex)
{
MessageBox.Show("Data file unable to be created. System message:{0}".Put(Environment.NewLine + Environment.NewLine + ex.Message));
}
}

In the comments to another answer you say this is a desktop application, so lets treat each location separately.
Under Vista and beyond, an ordinary user does not have rights to create files in the root directory of the system drive (usually C:). You can see this for yourself by opening C:\ in explorer, right clicking and trying to create a file - you should get a UAC prompt. So if you want to write to C:\ then your application needs to run as an administrator, via a suitable manifest demanding elevation, or by starting a separate process when you want to write to that location.
Application Data, Environment.SpecialFolder.ApplicationData should however work. If you output the actual directory that returns what do you get?

I can only imagine that the application must be running in the context of a user which does not have access to the local drive, e.g. an ASP.NET website running under the anonymous IIS account or a service account which only has access to the relevant network locations.

Most likely the external drive is formated with FAT. FAT does not support rights management for users, so saving there is ok.
Besides that the IIS User has no rights to the other folders like Adam mentioned already

Related

Read Files from Remote Drive in Intranet App

I want to read file names of pdfs from a folder on a network share that match certain parameters and provide a link to view them on a details page for my model. All I need to get is the file name. I don't need any file management/read/write at this time.
I'm able to display a .pdf in the browser if I have the path (IE will open "file://" links). The part I'm missing is getting file names from the remote (but same domain) directory at run-time.
We've set up a virtual directory for the app to use and that has worked fine in the past if the resolved physical folder is on the same server, but that is not the case here.
I've tried Impersonation, but that doesn't seem to work as I'm still getting an access is denied error.
I realize this would probably be a security issue and is why it isn't allowed, but is there an IIS configuration or other avenue that needs to be set-up to allow this? I can't seem to find a way with just code that opens the directory for reading.
Example code of how I might normally read some info from one file in a virtual directory:
// This example code is inside a controller action, so Server refers to HttpContextBase
var path = Server.MapPath("~/MyVirtualDirectory/" + fileName);
var fileExists = System.IO.File.Exists(path);
var fileLastModified = System.IO.File.LastWriteTime(path);
To enumerate over matching files in a directory, I've used DirectoryInfo
var pdfFileNames = new List<string>();
var dir = new DirectoryInfo(Server.MapPath("~/VirtualDirectory/"));
var pdfs = dir.EnumerateFiles("*.pdf");
foreach (var pdf in pdfs)
{
pdfFileNames.Add(pdf.Name);
}
As I mentioned, these methods work fine when the physical folder is on the same server, but once the directory is on a remote drive, then it no longer works. I have permissions to open the desired directory and my collegue said he gave the appropriate permissions to the virtual directory and server. Not sure what else to try at this point.
Edit: Now that it is working, I display the files using the Virtual Directory
http://server/appName/virtualDirectory/pdfFileName
By default, IIS application pools run under a specific local Windows identity named IIS APPPOOL\[NameOfYourAppPool]. This is a local user and it will not be possible to grant permissions to this identity to access resources located on a different machine.
If both servers are inside the same domain, you can try the following solutions:
Run the IIS application under a domain user and grant the required permissions to this domain user.
Run the IIS application under the NetworkService identity and grant permissions to the DOMAIN\MACHINENAME$ account of the IIS server.

Denied acces to a file

I have a code which is similar this:
string file;
using (StreamReader r = new StreamReader("xml.xml"))
{
file = r.ReadToEnd();
}
XElement xml = XElement.Parse(file);
using (XmlWriter w = XmlWriter.Create("xml.xml")) //The point of problem!
{
w.WriteStartDocument();
...;
w.WriteEndDocument();
}
When I try run it like a console application is everything all right. But problems start when I want to use it in an ASP.NET application. At the using line it throws UnauthorizedAccessException exception with a description "access to the path is denied". Why?
You need to check which account your application Pool is using to access your server files/folders, for example, make one code to copy one file to application folder, check all security info, copy and paste on this problem folder, normally use this account "IIS_IURRS" give full control to test only...
If IIS/the web server is configured correctly, an account with a very limited set of permissions is used. As your path points to the application directory, it is very likely that the application pool account is not allowed to write to this location.
If you run the code in a console application, your user's permissions are applied and it is more than likely that you are allowed to write to the output folder of the project as Visual Studio writes the build output there under your account.
I would not recommend to change the application pool account or the permissions of the application folder in the file system - it is a very sensible limitation that limits the amount of trouble an attacker can possibly make.
Therefore I'd recommend to either move the file to a folder that the account can write to without changing permissions or define a special one outside of the application folder hierarchy that the account is given permissions to.
Also keep in mind that multiple users might access the file at the same time, so a database might be a better choice to store the data.

Environment.SpecialFolder.ApplicationData returns the wrong folder

I have a strange problem: my .NET 4.0 WPF application is saving data to the ApplicationData folder.
Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) + "\\myProgram\\";
99.9% of the cases are working great, but on some computers it returns the wrong folder - instead of returning the user folder it returns another folder:
C:\Users\<user>\AppData\Roaming\myProgram\ --correct
C:\Users\s\AppData\Roaming\myProgram\ --wrong
The wrong folder has no write/read permission so my program doesn't work.
It seems the program is running under a different user, but if I check the Task Manager the user is the logged one.
The problem seems to be occurring with domain users with few permissions.
Do you also create a text file to write?
If so save a file such as:
String path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
var filePath = Path.Combine(path, "filetowrite.log"); // Handles whether there is a `\` or not.
if (File.Exists(filePath))
{
......................
}
Note also before doing any file operations, one should check if directory exists.

Access to the path .... is denied

I have created a .msi by using VS2008 setup project. My application frequently writes some value in a .txt file in the application directory (C:\Program Files\MyApp\MyFile.txt). After insalling it in Win7, it raises an exception "Access to the path .... is denied."
But whenever I run it as administrator, no such exception occurs. Here is my sscce
string FilePath=Application.StartupPath + #"\AppSettings\CurrentUserName.inf";
using (StreamWriter writer=new StreamWriter(FilePath,false))
{
writer.Write(txtLoginName.Text.Trim());
}
MainForm.ProcessLogIn();
this.DialogResult = DialogResult.OK;
I don't know how to solve this problem. Any suggestion?
Move your file out of Program Files directory. In Win7 is readonly for normal users.
You could move the file in the ProgramData directory.
Your installer should create a directory for your application there.
Then inside your code you could retrieve the correct full pathname using these lines of code
string dataPath = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData));
string appFile = Path.Combine(dataPath, "MyAppDir", "MyFile.txt");
usually (on Win7) this result in a path like this
c:\programdata\MyAppDir\MyFile.txt
but using the SpecialFolder enum you are guaranteed to use a folder available in readwrite to your application not depending on the current operating system.
The only way to solve this problem is to not write to that folder. You are not allowed to write to that folder by convention, unfortunately, older versions of Windows did not hold you to this.
Instead, you can use Environment.SpecialFolder to help you find where you need to go:
// your application data for just that User running the app
var perUserAppData = Environment.GetFolderPath(
Environment.SpecialFolder.ApplicationData);
// your application data for ALL users running the app
var allUsersAppData = Environment.GetFolderPath(
Environment.SpecialFolder.CommonApplicationData);
// better!
var path = Path.Combine(perUserAppData, #"MyApp\MyFile.txt");
Basically, Windows 7 is telling you that you're going to have to stop driving on the sidewalks and use the street as was intended.
As a short-term fix, you can use ICACLS to grant write access to the file. Note: NOT the whole directory.
As a longer term fix, you should NOT write to the program directory if you are running as unprivileged users, but instead somewhere like %LOCALAPPDATA% or %APPDATA%.

Why is access to the path denied?

I am having a problem where I am trying to delete my file but I get an exception.
if (result == "Success")
{
if (FileUpload.HasFile)
{
try
{
File.Delete(Request.PhysicalApplicationPath + app_settings.login_images + txtUploadStatus.Text);
string filename = Path.GetFileName(btnFileUpload.FileName);
btnFileUpload.SaveAs(Request.PhysicalApplicationPath + app_settings.login_images + filename);
}
catch (Exception ex)
{
Message(ex.ToString());
}
}
}
Also I should note that the folder I am trying to delete from has full control to network services.
The full exception message is:
System.UnauthorizedAccessException: Access to the path 'C:\Users\gowdyn\Documents\Visual Studio 2008\Projects\hybrid\hybrid\temp_loginimages\enviromental.jpg' is denied. at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) at System.IO.File.Delete(String path) at hybrid.User_Controls.Imgloader_Add_Edit_Tbl.btnUpdate_Click(Object sender, EventArgs e) in C:\Users\gowdyn\Documents\Visual Studio 2008\Projects\hybrid\hybrid\User_Controls\Imgloader_Add_Edit_Tbl.ascx.cs:line 242
Any ideas?
According to File.Delete Method...
An UnauthorizedAccessException means one of 4 things:
The caller does not have the required permission.
The file is an executable file that is in use.
Path is a directory.
Path specified a read-only file.
I also had the problem, hence me stumbling on this post. I added the following line of code before and after a Copy / Delete.
Delete
File.SetAttributes(file, FileAttributes.Normal);
File.Delete(file);
Copy
File.Copy(file, dest, true);
File.SetAttributes(dest, FileAttributes.Normal);
This is an old issue, but I ran into it while searching. Turns out that I was missing the actual filename component in the save path for SaveAs...
string uploadPath = Server.MapPath("~/uploads");
file.SaveAs(uploadPath); // BAD
file.SaveAs(Path.Combine(uploadPath, file.FileName)); // GOOD
When a user tries to connect to your Web site, IIS assigns the connection to the IUSER_ComputerName account, where ComputerName is the name of the server on which IIS is running. By default, the IUSER_ComputerName account is a member of the Guests group. This group has security restrictions. Try to grand access to IUSER_ComputerName to that folder
Here is very good described answer about IIS security
Hope this helps
I got the error because I didn't realize that the destination should be a file. I had a folder as the second parameter (which works in cmd). and I got Unhandled Exception: System.UnauthorizedAccessException: Access to the path is denied. because C# File.Move wants a file there, not just for the first parameter, but for the second too, and so if you put a directory as second parameter, it's trying to write a file like c:\crp when you have a directory called c:\crp.
this would be incorrect File.Move(args[0],"c:\\crp");
So, this would be correct File.Move(args[0],"c:\\crp\\a.a");
The same goes for File.Copy
Right-click on Visual studio and click Run as Administrator
Thanks for +1
If this is an IIS website that is having the problem, check the Identity property of the advanced settings for the application pool that the site or application uses. You may find that it is set to ApplicationPoolIdentity, and in that case then this is the user that will have to have access to the path.
Or you can go old style and simply set the Identity to Network Service, and give the Network Service user access to the path.
You need to modify the privileges of the folder you're trying to delete from/save to. Right-click on the containing folder and use the Security tab to permit modify rights for the user your application runs under.
An UnauthorizedAccessException exception is thrown when the operating system denies access because of an I/O error or a security error.
If you are attempting to access a file or registry key, make sure it is not read-only.
I have also faced this issue when my window service started throwing the exception
System.UnauthorizedAccessException: Access to the path "C:\\Order\\Media
44aa4857-3bac-4a18-a307-820450361662.mp4" is denied.
So as a solution, I checked the user account associated with my service, as shown in below screen capture
So in my case it was NETWORK SERVICE
And then went to the folder properties to check if the associated user account also exists under their permission tab. It was missing in my case and when I added it and it fixed my issue.
For more information please check the below screen capture
same issue for me too,
I was pointing the folder instead of file.
so make sure in path, give path+filename
System.IO.File.WriteAllBytes("path", bytearray);
The exception that is thrown when the operating system denies access
because of an I/O error or a specific type of security error.
I hit the same thing. Check to ensure that the file is NOT HIDDEN.
Check your files properties. If the read-only is checked, uncheck it. This was my personal issue with the UnauthorizedAccessException.
I got this error and solved it in just a moment. Don't know why all of my folders are read-only,I cancelled the read-only and apply it. However, it is still read-only. So I moved the file into the root folder, it works - so weird.
I was facing this error because
Sometimes when I Combine the path with File Name and FileName = ""
It become Path Directory not a file which is a problem as mentioned above
so you must check for FileName like this
if(itemUri!="")
File.Delete(Path.Combine(RemoteDirectoryPath, itemUri));
I was trying to use System.IO.File.OpenWrite(path)
and it did not work because I was only passing OpenWrite() a path to a directory, but it requires a path all the way to the file you want to write. So a full path including the filename.extension at the end needs to be passed into OpenWrite to avoid UnauthorizedAccessException
In my case the problem was Norton. My in-house program doesn't have the proper digital signature and when it tried to delete a file it gave the UnauthorizedAccessException.
If it give you a notification, you can handle it from there. In my case it didn't give a notification that I noticed. So here's how to keep Norton from blocking the program.
Open Norton
Click the down arrow
Click History
Find activity by program
Click More Options
Click Exclude Process
To solve this problem, I follow the Scot Hanselman approach at Debugging System.UnauthorizedAccessException (often followed by: Access to the path is denied) article, the code with example is bellow:
class Program
{
static void Main(string[] args)
{
var path = "c:\\temp\\notfound.txt";
try
{
File.Delete(path);
}
catch (UnauthorizedAccessException)
{
FileAttributes attributes = File.GetAttributes(path);
if ((attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
{
attributes &= ~FileAttributes.ReadOnly;
File.SetAttributes(path, attributes);
File.Delete(path);
}
else
{
throw;
}
}
}
}
I had the same problem on a newly moved website on a shared server. Solved through the web host panel (DotNetPanel) setting true the "allow write permissions". So if you are in a shared server before reviewing all code worth taking a look at the server configuration and could save you a lot of time.
Be aware that if you are trying to reach a shared folder path from your code, you dont only need to give the proper permissions to the physicial folder thru the security tab. You also need to "share" the folder with the corresponding app pool user thru the Share Tab
I had the exact error when deleting a file. It was a Windows Service running under a Service Account which was unable to delete a .pdf document from a Shared Folder even though it had Full Control of the folder.
What worked for me was navigating to the Security tab of the Shared Folder > Advanced > Share > Add.
I then added the service account to the administrators group, applied the changes and the service account was then able to perform all operations on all files within that folder.
For those trying to make a UWP (Universal Windows) application, file permissions are much more restricted, and in general is deny by default. It also supersedes the system user permissions. You will basically only have access to files in either
Your install location
Your AppData location
Files selected through the File or Folder picker
Locations requested in your App Manifest
You can read more here for details => https://learn.microsoft.com/en-us/windows/uwp/files/file-access-permissions
If you're using BitDefender there's a good chance its Safe Files feature blocked your operation. This is a form of Ransomware protection that comes with some of its more advanced versions.
Make sure to grant your application access in BitDefender and try again.
Some more details can be found in this BitDefender support page.
In my case it was my AVG anti-virus that triggered the exception.
I added my VS Projects directory to the "Allowed" list. And I had to add the executable to the AVG exceptions list after I copied the .exe to my App directory.
I've had the same problem and I've managed to get it working by changing the partition on which the file will be saved. So, on line 5 I've changed #"C:\" to be #"D:\" and that resolved the problem.
static void SaveVideoToDisk(string link)
{
var youTube = YouTube.Default; // starting point for YouTube actions
var video = youTube.GetVideo(link); // gets a Video object with info about the video
File.WriteAllBytes(#"D:\" + video.FullName, video.GetBytes());
}
After migrating from Visual Studio 2017 to Visual Studio 2019 I faced two exceptions with two of my applications which run properly under Visual Studio 2017:
System.UnauthorizedAccessException
System.ArgumentException
It turned out that I had to add the executables of the two applications to the allowed apps of Avast Antivirus.
I too faced the same problem when trying to do this after deployment at server:
dirPath = Server.MapPath(".") + "\\website\\" + strUserName;
if (!Directory.Exists(dirPath))
{
DirectoryInfo DI = Directory.CreateDirectory(dirPath);
}
string filePath = Server.MapPath(".") + "\\Website\\default.aspx";
File.Copy(filePath, dirPath + "\\default.aspx", true);
File.SetAttributes(dirPath + "\\default.aspx", FileAttributes.Normal);
I granted permission in IIS to other group including administrator and my problem got solved.
In my particular case I was repeatedly creating and deleting 10000 folders. It seems to me that the problem was in that although the method Directory.Delete(path, true) returns, the underling OS mechanism may still be deleting the files from the disk. And when I am starting to create new folders immediately after deletion of old ones, some of them are still locked because they are not completely deleted yet. And I am getting System.UnauthorizedAccessException: "Access to the path is denied".
Using Thread.Sleep(5000) after Directory.Delete(path, true) solves that problem. I absolutely agree that this is not safe, and I am not encouraging anyone to use it. I would love to here a better approach to solve this problem to improve my answer. Now I am just giving an idea why this exception may happen.
class Program
{
private static int numFolders = 10000;
private static string rootDirectory = "C:\\1";
static void Main(string[] args)
{
if (Directory.Exists(rootDirectory))
{
Directory.Delete(rootDirectory, true);
Thread.Sleep(5000);
}
Stopwatch sw = Stopwatch.StartNew();
CreateFolder();
long time = sw.ElapsedMilliseconds;
Console.WriteLine(time);
Console.ReadLine();
}
private static void CreateFolder()
{
var one = Directory.CreateDirectory(rootDirectory);
for (int i = 1; i <= numFolders; i++)
{
one.CreateSubdirectory(i.ToString());
}
}
}
First just check the path if the colon(:) character is missing or not after the drive letter. If colon is not missing then you can check if access/write permission is granted for that path.
I had the same issue and i was only missing the colon, permission and everything else was fine.
C:\folderpath
will work fine but,
C\folderpath .........(missing colon)
will give you access denial error.
I also ran into this post as dealing with the same issue. Looks like the file is in use and hence not able to write to it.
Though not able to figure it out, which process is using it. Signed out the other user who was logged in in that box, dont see any users who is holding it.
Any quick tips regarding on how to find the same.
Thanks,
Lakshay (developer)

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