I have a C# application, and I need to dump some output to a log file during operation. I am wanting to give the user the option of where to locate the log file, but by the client request it needs to default to the current application location, which is normally /Program Files/.
When I deploy my application on a Win7/Vista machine, though, the application does not write the log file unless I run the program as an Administrator. At the same time, it seems to be silently handling the case where it cannot write the file, as I am currently handling all exceptions being thrown during the file creation and writing process.
I am currently trying to detect lack of write permission by both:
A) Creating a DirectorySecurity object by calling "Directory.GetAccessControl()" and
B) Checking security priviledges with the "SecurityManager.IsGranted(permissions)" method,
but A does not throw an exception when I expect it to, and B returns true every time.
I have seen numerous posts related to this topic, but they all give the solution of just writing to Application.UserAppDataFolder or some variation of it. My client has specifically asked to default to the current Application path, so I need to at least find a way to gracefully warn them when writing the log file is going to silently fail.
Note: My current code works find on Windows XP (since there are no UAC, I assume). Basically all I need to know is why all my calls are telling me that writing the file is going fine, when the file is never created at all unless I am running as Admin.
Thanks!
Windows Vista and 7 will write files to the Program Files directory just fine.
Well, not really, but the program thinks it's just fine. In reality, the file is written to the current user's VirtualStore directory; that is, in %userprofile%\AppData\Local\VirtualStore\Program Files
You can include a manifest file to disable this behavior for your application to get the results you expect.
You can force the os to run your app as Admin.
<requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
There are three ways your app can run - elevated, deliberately not elevated (manifest saying asInvoker), or accidentally not elevated (no manifest). Elevated apps will be able to write to Program Files. Deliberately not elevated apps will get access denied. Accidentally not elevated apps will succeed but the file will be written elsewhere. This last case is what's happening to you. It didn't silently fail. You just don't know where the files are. See http://www.gregcons.com/KateBlog/FindingFilesYoureSureYouWrote.aspx for screenshots.
Therefore if the users insist on the current directory, you should add a manifest requesting asInvoker. You will then get AccessDenied and they will see the error message. I think they are odd for wanting this. Ask them if they are ok with one extra click to find them: if so, keep your app using virtualization (I really disapprove) by having no manifest and then train them to click the Compatibility Files button.
My preference: write elsewhere and manifest to asInvoker. My second choice: stick with current directory, no manifest, train them to find virtualized files. My third choice: stick with current directory, manifest to asInvoker, users see error messages when log files are not written, but logs are lost.
I am experiencing the same problem. I have an xml file that i am writing to...When I install the app(C sharp) and try to run the application am getting an exception due to write permission. When I change the file permission (give read permission to users) it is working ok..
The ultimate test for whether you have the rights to write a file is to open it for writing.
I.e.
try
{
File.Open(path, FileMode.OpenOrCreate);
...
}
catch(SecurityException)
{
... it failed for security reasons
}
catch(Exception)
{
... it failed for other reasons
}
Besides Stefan P.'s suggestion to elevate the app to run as admin, you could also modify the installation folder permission on install to to add the Users group to have write access. Then the application would work as well.
Moving the log file location would be the best option though.
Related
I have read other questions on SO in regards to security and registry keys, nothing has helped me solve my particular use case scenario.
Here's my scenario:
What I'm Trying To Do
I want to, in code, delete a windows event log.
The Problem
When executing the function, I receive a System.ComponentModel.Win32Exception. The exception message is "Access is denied".
How I Am Doing It Currently
I am using an impersonator function that I wrote which wraps around the EventLog.Delete function, it drops me into a user context that has full access to the EventLog Registry Hive. Subsequently the logs I am interested in also have full access for this particular user.
My Question
Why do I receive a "Access Is Denied" if the user I am running under (through impersonation) has full access to the log in question? I've tested my Impersonation function and it works as expected for other code I've written. I don't get why I would get access denied for this.
In another scenario with my impersonation function it works just fine, for example if I tried to write to a file that the user context that is running the program does not have write access to, then I would not be able to write to the text file, however if I use my impersonation to drop into a user context that does have write access then it works just fine (I can write to the file). So I just don't understand why the same concept can't be applied to registry keys.
What am I missing here?
The Code
Exception Message
My Test
Where sw-test is a user I created for testing purposes, it has full access permissions to the registry we are trying to delete.
[TestMethod]
public void DeleteEventLog_ValidatedUser_DeleteLog()
{
using (new Impersonator(Environment.UserDomainName, "sw-test", "pswd"))
{
Logging logging = new Logging();
logging.DeleteEventLog("testLog");
}
}
Okay I eventually got around to figuring this out, there were two issues at play here that were causing the mentioned exception being thrown, they are as follows:
1. Visual Studio was NOT running in administrator mode.
Not running visual studio in administrator mode was one part of the problem, this seems to be associated with access tokens in the windows OS. According to a source I read, if I run a program without UAC on (which is my scenario, I have it off), then the program being run gets a copy of my access token. However if I have UAC enabled, the program gets a copy of my access token but it is a restricted access token. (see: What precisely does 'Run as administrator' do?) - To be honest this doesn't really make sense in my case, why do I have to run as admin if I have UAC off? Shouldn't visual studio have an unrestricted copy of my access token? I am in the administrator group with UAC off...
2. Not Specifying NewCredentials As a Logon32Type In Impersonation
I don't really understand it but as soon as I specified this for my impersonation everything started working perfectly, I read a blog about it, it talks about how it was introduced in the VISTA days and how it was mainly used to specify credentials to outbound network connections to servers, and was mainly used to remedy security-related issues server-side. Don't see how it correlates to interfacing with local event logs though. (see: https://blogs.msdn.microsoft.com/winsdk/2015/08/25/logonuser-logon32_logon_new_credentials-what-is-this-flag-used-for/)
Code
using (new Impersonator(Environment.UserDomainName, "sw-test", "pswd", Advapi32.Logon32Type.NewCredentials))
{
EventLog.CreateEventSource("testSource", "testLog");
EventLog.Delete("testLog");
}
Where the NewCredentials is an int 9
I am getting the
A first chance exception of type 'System.UnauthorizedAccessException'
occurred in mscorlib.dll
exception from this bit of code:
string[] filesList = Directory.GetFiles(#"C:\Program Files (x86)\", "*.exe",
SearchOption.AllDirectories);
What its doing is listing all files with an .exe extention, although for certain directories it works, but some it throws this.
Any ideas on what I can do to resolve it would be greatly appreciated!
You need to run your app as admin.
Here's he right way to do it:
http://blogs.msdn.com/b/nikhiln/archive/2007/04/19/embed-a-manifest-to-make-an-application-elevate-in-vista.aspx
On some versions of windows, the program files directories are pretty well locked down. This prevents errant users from damaging the parts of the file system essential for correct OS running. If you run your debugger (and application) with elevated privileges then it will pass.
If you using Vista, Program Files folder is protected by operating system by UAC.
Applications written with the assumption that the user will be running
with administrator privileges experienced problems in earlier versions
of Windows when run from limited user accounts, often because they
attempted to write to machine-wide or system directories (such as
Program Files) or registry keys. UAC attempts to alleviate this
using File and Registry Virtualization, which redirects writes (and
subsequent reads) to a per-user location within the user’s profile.
For example, if an application attempts to write to “C:\program
files\appname\settings.ini” and the user doesn’t have permissions to
write to that directory, the write will get redirected to
“C:\Users\username\AppData\Local\VirtualStore\Program Files\appname\settings.ini”
And be aware, Program Files is special folder. If you want to get its path, you can use Environment.SpecialFolder enumeration. Like;
Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles)
I know there is a ton of stuff on this already and have tried a few things but have had no luck in fixing it.
I have a C# program that has built an XML Document and im trying to save it to a folder thats in MyDocuments. I am getting the folliwing exception when calling the XMLDoc.Save function.
Access to the path 'C:\Users\Ash\Documents\ConfigOutput' is denied
I have visual studio running as administrator. Any thoughts on how to fix it?
I have tried saving onto the desktop and into the C:\ folder aswell.
I am using windows 7.
Running the built executable also doesnt seem to work.
Apologies guys it seems I was being stupid. I had indeed not added a filename to the output path. I'll not delete the question incase anyone else gets done by this gotcha! Thanks for all the help/comments.
There are a few possibilities:
ConfigOutput is a folder
ConfigOutput is a file that is in use (opened)
You're not logged in as User 'Ash'
You should not normally have to run as Admin to write to your own Documents folder.
You need to check and get permission to that directory/file your writing.. for that
use Security namesapce
var permissionSet = new PermissionSet(PermissionState.None);
var writePermission = new FileIOPermission(FileIOPermissionAccess.Write, pathToFolder);
permissionSet.AddPermission(writePermission);
if (permissionSet.IsSubsetOf(AppDomain.CurrentDomain.PermissionSet))
{
// do your stuff
}
else
{
// alternative stuff
}
It looks like you're not specifying a filename and therefore it can't create a file with the same name as an existing directory - so try changing your path to:
C:\Users\Ash\Documents\ConfigOutput\Out.xml
Try run your app as administrator.
If you want to debug your app, start your Visual Studio as administrator also.
To force app start as administrator take a look at this thread:
How do I force my .NET application to run as administrator?
P.S. Check if your file is not already opened by another FileStream or etc.
I don't know if this makes a difference, but you may want to specify the folder in a relative rather than absolute manner: Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) will provide you with the path of the current user's documents. Check if it's different from the one you provide.
If so, you may need to run the app under a different user or administrator as others have pointed out. Obviously one user isn't allowed to just save files into another user's documents folder.
For me when I debug my app from Visual Studio the documents folder is the same as the user I'm currently logged in as and running Visual Studio under.
You could try <requestedExecutionLevel
level="asInvoker"
uiAccess="true|false"/> first and progressively move to highestAvailable and requireAdministrator.
Alternatively, demand the permissions, catch the exception and print it out:
try {
FileIOPermission fileIOPermission = new FileIOPermission(FileIOPermissionAccess.AllAccess, myDocFolderFile);
fileIOPermission.Demand();
} catch (SecurityException se) {
Debug.WriteLine(se.ToString());
}
I am doing an project from my school and I am trying to delete a file from Windows XP.
However, I encounter this error, even after I set the attribute of the file.
Access to the path is denied"
The file is in C:\Document and Settings\%user%\Local Settings\Temp.
How can this be solved?
if(File.Exists(filePath))
{
FileSecurity sec = File.GetAccessControl(filePath);
sec.AddAccessRule(new FileSystemAccessRule(Environment.UserName,
FileSystemRights.FullControl, AccessControlType.Allow));
File.SetAccessControl(filePath, sec);
File.SetAttributes(filePath, FileAttributes.Normal);
File.Delete(filePath);
}
FileSecurity sets permissions on the file itself. Thats all great but it doesn't mean you have the permission to Delete it. Try running your app as an administrator and see if that makes a difference.
That means that another program is using the file.
You must close the file (or the entire program) before you can delete it.
If your program uses the file, make sure to close (not cross) the streams.
Check whether you have "admin" or related permission to delete the files.
If you have admin authority, then check whether the file which you have mentioned has other "rights" Ex: few MS files cannot be deleted.
Check whether you have specified the right file name.
If you have verified all these then this file either you have opened it or in your code you have not closed it to delete it.
Even if the above solution doesn't work then this file is either corrupted or some other user or yourself are still using this file which is not closed.
So far, the code block is okay.
However, keep in mind the below things:
a. In case of Windows XP, with the user you logged in - make sure that the user is in administrator group and the user will have admin access, so any application running by the user will have admin privileges.
b. In case of other updated Windows like Vista, Windows 7, try running the application as an administrator ( right click on application and the click on "run as administrator" from the pop-up, while checking in development time - run your IDE as administrator ).
Hope this would be helpful.
I am trying to use eventlogs in my application using C#, so I added the following code
if (!EventLog.SourceExists("SomeName"))
EventLog.CreateEventSource("SomeName", "Application");
The EventLog.SourceExists causes SecurityException that says
"The source was not found, but some or all event logs could not be searched. Inaccessible logs: Security."
I am running as administrator in Windows 7.
Any help would be appriciated.
This is a permissions problem - you should give the running user permission to read the following registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\EventLog
Alternaitvely you can bypas the CreateEventSource removing the need to access this registry key.
Both solutions are explained in more detail in the following thread - How do I create an Event Log source under Vista?.
Yes, it's a permissions issue, but it's actually worse than indicated by the currently accepted answer. There are actually 2 parts.
Part 1
In order to use SourceExists(), the account that your code is running under must have "Read" permission for the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\EventLog key and it must also have "Read" permissions on each of the descendant-keys. The problem is that some of the children of that key don't inherit permissions, and only allow a subset of accounts to read them. E.g. some that I know about:
Security
State
Virtual Server
So you have to also manually change those when they exist.
FYI, for those keys (e.g. "State") where even the Administrator account doesn't have "Full Access" permission, you'll have to use PsExec/PsExec64 to "fix" things. As indicated in this StackOverflow answer, download PsTools. Run this from an elevated command prompt: PsExec64 -i -s regedit.exe and you'll them be able to add the permissions you need to that key.
Part 2
In order to successfully use CreateEventSource(), the account that your code is running under must have "Full Control" permissions on HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\EventLog as well as have "Full Control" permissions on the log you're adding the new source to.
But wait, there's more...
It is also important to know that both CreateEventSource() and WriteEntry() call SourceExists() "under the hood". So ultimately, if you want to use the EventLog class in .Net, you have to change permissions in the registry. The account needs "Full Control" on the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\EventLog key and "Read" for all children.
Commentary: And I believe all of this mess is because when Microsoft originally designed the EventLog, they decided it was critical that people would be able to log something by "Source" without needing to know what log that "Source" went with.
Short tip:
One event source is registered during Service instalation (if application is Windows Service), and can be used without Security Exception with low-profile process owner (not Administrator)
I perform service installation / run with C# code in typical way from SO/ MSDN
Important is property ServiceName in class System.ServiceProcess.ServiceBase .
Good afternoon,
The simplest is that you run vs2019 as an administrator, so when debugging or excute the service, it will run correctly without generating the exception.