Custom Installer Creating Folder, Setting Permissions

When implementing custom installers you sometimes may want to created directories when the setup is executed. This may not be sufficient since you may also want to set sufficient permissions on those new directories so that users have access to the directories and the files in them.

The first thing to know is that an installer typically runs with elevated rights as the discussion on Chris Jackson's blog indicates. This means that your installer has sufficient rights to create directories but also to set appropriate permissions.

And here is the code for creating a directory and setting permissions:

public static void CreateWithReadAccess(string targetDirectory) {
try {
if(!Directory.Exists(targetDirectory)) {
Directory.CreateDirectory(targetDirectory);
}
DirectoryInfo info = new DirectoryInfo(targetDirectory);
SecurityIdentifier allUsersSid =
new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid,
null);
DirectorySecurity security = info.GetAccessControl();
security.AddAccessRule(
new FileSystemAccessRule(allUsersSid,
FileSystemRights.Read,
AccessControlType.Allow));
info.SetAccessControl(security);
}
catch(Exception ex) {
Debug.WriteLine(ex.ToString());
}
}

This code checks for existence of the directory first. If the directory doesn't exist yet it is created. Then the security settings are applied. In this case the Read permissions are granted to all members of the group BUILTIN\Users.

By selecting another member of the WellKnownSidType enumeration you can grant permissions to a different group. Alternatively, if you'd like to grant permissions to a specific user, have a look at the NTAccount class. An instance of it can be passed into the FileSystemAccessRule constructor as a first parameter as well.