Santomania : .NET

Code Snippet: Working with Permissions (ACLs/ACEs) in C# under .Net 1.1

Addys — Mon, 23 Jan 2006 01:27:00 GMT

I've been working lately on adding "self-healing" capabilities to a certain application. The idea is to create a set of utility functions which will validate (and fix if needed) various environmental settings such as NTFS permissions, registry permissions, IIS metabase settings, etc. None if this is rocket science but there still was some work involved in bringing it all together, so I'll list it here in case I (or you) ever need to do it in the future.

Note: For anything related to security in 1.1, the Windows32.Security library (written by Renaud Paquay) is an indispensable resource.

Snippet #1: Check for permissions on a registry key (using Windows32.Security)

public bool TestRegistryKeyPermissions(string keyName, string userName)
{
      // get a handle to the key 
      IntPtr hKey; 
      if (Microsoft.Win32.Security.Win32.RegOpenKey(Win32Consts.HKEY_LOCAL_MACHINE, keyName, out hKey) != Microsoft.Win32.Security.Win32.SUCCESS) 
      { 
            return false;
      } 
      try 
      { 
            // get the security descriptor 
            using (SecurityDescriptor sd = SecurityDescriptor.GetRegistryKeySecurity (hKey, SECURITY_INFORMATION.DACL_SECURITY_INFORMATION)) 
            { 
                  // check whether the specified user has an ACE in the ACL 
                  Dacl acl = sd.Dacl; 
                  return TestAcl(acl,userName);
            }     
      }     
      catch
      {
            return false;
      }
}
 
public static bool TestAcl(Dacl acl, string userName) 
{
      for(int i=0; i<acl.AceCount;i++)
      {
            Ace ace= acl.GetAce(i);
            if (ace.Sid.AccountName == userName) 
            {
                  return true;
            }
      }
      return false;
}
 
Snippet #2:   Set permissions on a registry key (using Windows32.Security) 
 
public static void SetRegistryKeyPermissions(string keyName, string userName)
{
      // get a handle to the key 
      IntPtr hKey; 
      if (Microsoft.Win32.Security.Win32.RegOpenKey(Win32Consts.HKEY_LOCAL_MACHINE, keyName, out hKey) != Microsoft.Win32.Security.Win32.SUCCESS) 
      { 
            throw new Exception ("failed to access registry key " + keyName); 
      } 
 
      try 
      { 
            // get the security descriptor 
            using (SecurityDescriptor sd = SecurityDescriptor.GetRegistryKeySecurity (hKey, SECURITY_INFORMATION.DACL_SECURITY_INFORMATION)) 
            { 
                  // give the service user standard read access. 
                  Dacl acl = sd.Dacl; 
                  Sid serviceUserSID = new Sid(userName); 
                  acl.RemoveAces (serviceUserSID); 
                  
                  AccessType aclAccessType =  AccessType.GENERIC_ALL ;
                  acl.AddAce (new AceAccessAllowed (serviceUserSID, aclAccessType , AceFlags.OBJECT_INHERIT_ACE | AceFlags.CONTAINER_INHERIT_ACE));
                        
                  // set the values 
                  sd.SetDacl(acl); 
                  sd.SetRegistryKeySecurity (hKey, SECURITY_INFORMATION.DACL_SECURITY_INFORMATION); 
            } 
      } 
      finally 
      { 
            Microsoft.Win32.Security.Win32.RegCloseKey (hKey); 
      } 
}

VS.NET Bug? Easter Egg?

Addys — Sun, 02 Oct 2005 22:53:00 GMT

After "Collapsing to Definitions" (Cntl-M,Cntl-O), Visual Studio decided to color the collapsed code section in black, white and red:

Can anyone clue me in on what/why that is? It happened consistently while VS.NET was open, but only for that specific method. After rebooting VS.NET I can't recreate this, so its a good thing I took a screenshot.

This is VS.NET 2005 RC1.

A tip, a tool and a book

Addys — Thu, 24 Mar 2005 19:57:00 GMT

The Tip: If your mouse has thumb buttons, they are usually mapped (by default) to "back" and "forward" in IE. Change those to PgUp and PgDown, and give it a test drive in Visual Studio. I never noticed how much of my development time was being spent on paging... much better now!

The Tool: Resharper is without a doubt the best 99$ I ever spent on a dev add-in. I find that I don't use the advanced refactoring tools very often, but the simple things such as renaming members and converting variables to properties is very handy. My favorite features are (by far) the many small improvements to the VS.NET environment such as quick-navigation tools and improved intellisense. There are many similar add-ins - some of them freeware - but from what I have seen so far Resharper seems to have the best combination of features, usability and general polish.

The Book: Microsoft Windows Sharepoint Services, Inside Out, Jim Buyens, Microsoft Press. I'm not a big fan of the Inside Out series, but this book is awesome. It covers design, installation, administration, customization and custom development of WSS, and somehow manages to stay readable from the basic concepts through to the advanced minutia in each topic. I usually get frustrated very quickly with non-electronic documentation (bookmarks didn't originate with the internet - who knew?) but this book is one which I actually plan to read cover-to-cover. At 700+ pages it might take me a while, but I'll post a more detailed review when I'm done.

WssDal - a Sharepoint Web Services alternative

Addys — Thu, 03 Mar 2005 01:33:00 GMT

About 2 months ago I asked if anyone was interested in an alternative to the WSS webservices. A few people responded and tried my WssDal library. The general consensus seems to be that while it isn't perfect, it is useful enough to continue developing. So if anyone else wants to give it a test drive, the library (complete with full source code, some light samples, setup instructions and documentation) is available HERE.

Bug reports, feature requests, etc are most welcome. If there is any interest in collaboration I'll happily open a workspace on GDN or SourceForge for this.

As with any code downloaded from my blog: you use this at your own risk. See the full disclaimer on my blog homepage if you don't know what I mean by that.

3/7/2005 Update: In the first 5 days WssDal was downloaded over 200 times. So how about some feedback? I want to make it better, but I need your input!

Random musings and an Infopath tip

Addys — Fri, 18 Feb 2005 05:39:00 GMT

Random musings... I have had too much sugar today and too little sleep last night, so my brain is a little fried. Consider yourself warned :)

My current gig is for a hospital. Every evening when I leave the parking lot, the automated toll machine remarks "thank you and please come again". Is that really the best farewell they could come up with? Who wants to be in a hospital to begin with?
A fortune cookie from lunch read "Your happy heart brings joy and peace where there is none". Those bastards must have been peeking at my job description. Ah, consultant humor ;)
TechBargains.com rocks - I picked up a pair of 250GB HDs for 70$ each. :)
While configuring the new drives (for RAID 1), the Dell administration tool 'spontaneously' decided to format my boot partition. Dell sucks, there goes my weekend :(

And not to be totally off-topic, an Infopath development tip... Using a web page to spawn an Infopath form is a simple yet powerful solution for integrating Infopath into your existing web systems. For example:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim RequestNum As String = Request("ID")

Dim FormXml as String = myBizObject.GetInfopathXML(RequestNum)

Response.ContentType = "application/ms-infopath.xml"

Response.Write(FormXml)

End Sub

Notice the "secret ingredient" - Since IE ignores the form PI which ties it to Infopath (presumably for security reasons), if the ContentType is not set correctly then the xml data will be displayed in the browser. Setting the ContentType to "application/ms-infopath.xml" ensures that IE will spawn Infopath.

Are the Sharepoint Web Services too complex? Looking for something better?

Addys — Fri, 31 Dec 2004 04:50:00 GMT

I'm looking for a few people to help beta-test an alternative to Sharepoint's web services. The solution allows a simple "object modelish" approach to working with WSS, as shown by the following sample code snippets:

// display all fields of all items of all lists
ListsClient ListClient = new ListsClient();

foreach (ListDescriptor list in ListClient.GetLists("http://WssSite"))
{
     Console.WriteLine("List {0} has {1} items",list.ListName,list.ListItems.Length.ToString());
     foreach(ListItem item in list.ListItems)
     {
           Console.WriteLine("item {0} fields:",item["Title"]);
           foreach(Field f in item.Fields)
                Console.WriteLine("{0} = {1}",f.Name,f.Value);
     }
}

// update all list items in the "Tasks" list which are due today

ListDescriptor tasks = ListClient.GetListItemsByFieldValue("http://WssSite","Tasks","DueDate",strToday);

foreach(ListItem task in tasks.ListItems)

{

task["Description"] += " <-- DUE TODAY!!";

ListClient.UpdateListItem("http://WssSite","Tasks",task);

}

It also solves some of the WSS web service pain-points, such as download/upload, checkin/checkout, etc.

~~Drop me a mail if you are interested.~~ 3/3/2005 Update: The source is now available for download, more details here

Fixing Broken Links after Restoring a Sharepoint (WSS) Site with SMigrate

Addys — Wed, 29 Dec 2004 08:12:00 GMT

Utility and source code here (http://www.addysanto.com/blog/fixsitelinks.zip)

Introduction

WSS 2.0 includes a utility called SMigrate which can be used to backup the content and structure of a site and to later recreate a site’s content and structure from the backup file. SMigrate also enables migration scenarios – by backing up a site and restoring it to a different URL, it is possible to migrate content between different sites or servers.

When restoring content to a different URL SMigrate attempts to update the necessary links to ensure that the restored site will work correctly, including the Detail and Help links of webparts. In most cases, SMigrate will accurately update all of the webparts.

When using Frontpage (or other dev tools which circumvent the WSS UI) it is possible to create custom pages and webparts which will not be correctly updated by SMigrate when a site is restored. One possible solution is to manually update the broken links through the “Webpart Properties” page of the WSS UI , but manual corrections aren’t feasible for large sites or automated/scripted deployment scenarios.

FixSiteLinks is a utility which can fix such sites. When run, it scans webparts in ASPX pages in the site (in the root and all subdirectories) and attempts to correct any URLs which point to links outside the site.

Usage

FixSiteLinks accepts the following command line parameters:

-site URL

The site parameter specifies the base URL of the WSS site to scan.

-update (Optional parameter)

The update parameter causes FixSiteLinks to update any webpart links which point outside the scope of the current site (as defined by the “site” parameter). FixSiteLinks will not make any changes to the site if the –update parameter is not present.

The FixSiteLinks utility logs the results of each run into a file named FIXSITELINKS.OUTPUT.XML. This file documents the following information:

- Site Folders

o ASPX Pages in each Folder

§ Web Parts on each Page

· The original Detail Link of the webpart

· The suggested Detail Link of the webpart

· Action taken. Possible values are :

o Updated (if changes were made)

o Skipped (if –update wasn’t specified)

o None (if existing link is valid)

The output file is always created (regardless of the –update parameter) and is overwritten with each run.

I highly recommend first running the utility without the –update parameter and using the output file verify that the suggested changes make sense. If you are satisfied with the suggested changes then re-run the utility with the –update parameter to apply the changes. In the initial version there is no option for changing the default suggestions– if you don’t like them, don’t apply the changes via the –update parameter.

Notes

- This utility must be run on the server hosting WSS

- This utility requires administrative rights.

- ONLY RUN THIS IF YOU HAVE AN UP-TO-DATE SITE BACKUP. This hasn't caused any damage to my systems (yet?) but incorrect usage could easily corrupt your site so : Use this at your own risk!

- Don’t use the –update parameter before reviewing the suggested changes.

- Source code is included, feel free to modify as needed.

- “Nice to Haves” which didn’t make the cut in the initial version:

o More intelligent algorithm for correcting links

o Fine-grained control of which pages/webparts to update

Disclaimer

I DO NOT MAKE ANY CLAIM OF WARRANTY, EXPRESS OR IMPLIED, INCLUDING THE FITNESS FOR ANY PARTICULAR PURPOSE, OR ASSUME ANY LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THIS TOOL, NOR WILL I BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING BUT NOT LIMITED TO DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, OR DAMAGES FOR BUSINESS INTERRUPTION OR LOSS OF BUSINESS PROFITS OR DATA, RESULTING FROM USAGE OF THIS TOOL OR RELATED INFORMATION PRESENTED IN THIS POST.

Also: the entire physical universe, including the information provided herein, may one day collapse back into an infinitesimally small space. Should another universe or medieval re-enactment subsequently re-emerge, the existence of the this tool (and it’s proper functioning) in this universe cannot be guaranteed. YMMV.

The ultimate CMS (Content Management Server) resource list...

Addys — Wed, 22 Dec 2004 22:25:00 GMT

... is on Stefan Goßner's blog: http://blogs.msdn.com/stefan_gossner/articles/271524.aspx.

Human Workflow Services (HWS) - Just say no

Addys — Wed, 15 Dec 2004 23:38:00 GMT

In my Biztalk projects, I had several scenarios which sounded like a great fit for HWS. I spent a fair amount of time and effort but could never get HWS to cooperate. After a while I just gave up on it and advised customers to use standard Biztalk orchestrations when possible, or leapfrog HWS and go with 3rd party Biztalk supplements such as K2.NET.

I'm happy to see that I wasn't the only one who reached that conclusion. An article by Scott Woodgate - "Choosing the right workflow implementation with BizTalk Server 2004" - makes a similar recommendation and also states that HWS has no future in it's current form and in effect is being depreciated:

"...HWS will remain fully supported with no feature enhancements in the next version of Biztalk Server. The API set will be supported by PSS for at least ten years. However, the HWS APIs will likely be removed in the Longhorn Server timeframe. In the Longhorn Server timeframe concepts from HWS will be incorporated into the next generation orchestration technology for BizTalk Server and the broader platform. It is very likely that conversion from HWS to the Longhorn Server offering will be non-trivial as no automated migration is currently planned..."

.Net Deep Dive wrap-up

Addys — Fri, 26 Nov 2004 19:37:00 GMT

Yesterday's ".Net Deep Dive" day at Microsoft Israel was a huge success. Over 1600 developers came to the event to hear about advanced development topics such as Agile/TDD and Production Time Debugging. Both of Royo's lectures were packed, with people sitting on the floor after the 700 or so chairs were taken. I missed Jackie's lecture but I'm sure it was informative and fun - his lectures always are.

The knowledge and enthusiasm of the Israeli developer community never fails to amaze me. A little kid – who couldn't have been more than 10-12 years old - cornered Jackie in the "ask the experts" session to ask about the CLR's implementation of 64-bit value types on 32 bit hardware. And a little earlier in the session, Gadi mentioned that he had heard of an obscure registry key which was helpful when attaching NTSD to a running process. Someone from the audience stood up and recited the full name and path - from memory – and explained what it did.

This event really reminded me of how much fun I had as a speaker back in the days before joining MCS. Maybe my next position will provide more opportunities to participate in similar events. Giving the occasional user group presentation just doesn't give the same rush as a speaking to room with 500+ people...

Anyway, my vacation is coming to a close. On Sunday I'll be speaking at the .Net Architects user group followed by a Geek/Blogger Dinner, and then back to New York on Monday. Israel has been so much fun that I'm almost sorry to leave! J

Sharepoint Studies Roadmap

Addys — Fri, 29 Oct 2004 09:26:00 GMT

Gregory MacBeth recently posted an exhaustive 28-step roadmap for wannabe Sharepoint developers. IMHO some of the topics there aren't really required for Sharepoint development per-se (UML? UIP Application Block?) but the list is detailed and definitely worth checking out: http://weblogs.asp.net/gregmcb/archive/2004/10/25/247388.aspx

Updated Outlook Calendar Adapter for Blogwave Beta 1

Addys — Mon, 27 Sep 2004 13:15:00 GMT

Proving once again that Resistance Is Futile*, TristanK updates his Outlook Calender Adapter to support beta1 of BlogWave mere hours after it is released. And he even added a slick(er) new interface and an icon!

BlogWave version 0.3 (Alpha 3) - Released!

Addys — Fri, 20 Aug 2004 00:45:00 GMT

This release is full of cool new features. Drag-and-drop enables creating complex aggregate feeds in literally seconds. Context Menus. NNTP (newsgroup) support. A pluggable architecture and a C# code sample showing how to connect BlogWave to additional data sources . Whats not to like ?!?

Get it HERE (BlogWave_v03.zip, 531K)

=========================================================
BlogWave - Change Log
=========================================================

Version 0.3 (Alpha 3) - 8/19/2004

Added support for syndicating NNTP newsgroups. (Thanks Adam!)
Switched to an FTP library which supports unicode (Thanks Mark!)
When aggregating feeds, the aggregate feed title is set to BlogWave's 'Feed Title' , and the Source property in each item is set to the title of the originating feed. This is consistent with the aggregated views of .Text sites such as blogs.asp.net.
Context Menus are now accessible by right-clicking a feed. The menus mirror the options available in the task pane.
Added Drag-and-Drop support:
- Dragging a URL onto the feed pane will automatically create a new feed.
- Dragging a URL onto an existing feed in the feed pane will add a new source to the feed. (great for quickly creating aggregate feeds!)
- Both "http://" (for RSS sources) and "news://" (for NNTP sources) work with the drag and drop.
Source and Destination adapters are dynamically detected and loaded from the 'Adapters' subdir. Deploying additional adapters is as simple as copying the DLLs into that directory.
Exposed the .NET programming interface necessary to implement a source or destination adapter. So now anyone can write adapters for BlogWave :)
Added a sample project with an example in C# of an adapter implementation.
The Proxy Server support added in Alpha 2 still has issues with NTLM authentication.

"InteropServices.SEHException: External component has thrown an exception" - Solved!

Addys — Thu, 19 Aug 2004 02:22:00 GMT

I finally solved the problems with enabling XP Visual Styles (Themes) which I described here. My initial attempt worked on some computers but not others; apparently there is some mystic connection between the themed activation context, the color of my underwear and the current conversion rate from yen to zloty. Anyway, a huge thanks to Nat (whoever you are) for the helpful tips regarding various aspects of manifest creation and automation.

The solution? Skip the default C# implementation (which is buggy) and implement your own, as detailed here:

Microsoft Knowledge Base Article - 830033: HOW TO: Enable Office COM Add-ins to Opt-in to Windows XP Themes

or just copy the following code into a class:

using System.Runtime.InteropServices;

using System;

using System.Security;

using System.Security.Permissions;

using System.Collections;

using System.IO;

using System.Text;

using System.Windows.Forms;

[ SuppressUnmanagedCodeSecurity ]

internal class EnableThemingInScope : IDisposable

{

// Private data

private uint cookie;

private static ACTCTX enableThemingActivationContext;

private static IntPtr hActCtx;

private static bool contextCreationSucceeded = false;

public EnableThemingInScope(bool enable)

{

cookie = 0;

if (enable && OSFeature.Feature.IsPresent(OSFeature.Themes))

{

if (EnsureActivateContextCreated())

{

if (!ActivateActCtx(hActCtx, out cookie))

{

// Be sure cookie always zero if activation failed

cookie = 0;

}

~EnableThemingInScope()

{

Dispose(false);

}

void IDisposable.Dispose()

{

Dispose(true);

}

private void Dispose(bool disposing)

{

if (cookie != 0)

{

if (DeactivateActCtx(0, cookie))

{

// deactivation succeeded...

cookie = 0;

}

private bool EnsureActivateContextCreated()

{

lock (typeof(EnableThemingInScope))

{

if (!contextCreationSucceeded)

{

// Pull manifest from the .NET Framework install

// directory

string assemblyLoc = null;

FileIOPermission fiop = new FileIOPermission(PermissionState.None);

fiop.AllFiles = FileIOPermissionAccess.PathDiscovery;

fiop.Assert();

try

{

assemblyLoc = typeof(Object).Assembly.Location;

}

finally

{

CodeAccessPermission.RevertAssert();

}

string manifestLoc = null;

string installDir = null;

if (assemblyLoc != null)

{

installDir = Path.GetDirectoryName(assemblyLoc);

const string manifestName = "XPThemes.manifest";

manifestLoc = Path.Combine(installDir, manifestName);

}

if (manifestLoc != null && installDir != null)

{

enableThemingActivationContext = new ACTCTX();

enableThemingActivationContext.cbSize = Marshal.SizeOf(typeof(ACTCTX));

enableThemingActivationContext.lpSource = manifestLoc;

// Set the lpAssemblyDirectory to the install

// directory to prevent Win32 Side by Side from

// looking for comctl32 in the application

// directory, which could cause a bogus dll to be

// placed there and open a security hole.

enableThemingActivationContext.lpAssemblyDirectory = installDir;

enableThemingActivationContext.dwFlags = ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID;

// Note this will fail gracefully if file specified

// by manifestLoc doesn't exist.

hActCtx = CreateActCtx(ref enableThemingActivationContext);

contextCreationSucceeded = (hActCtx != new IntPtr(-1));

}

// If we return false, we'll try again on the next call into

// EnsureActivateContextCreated(), which is fine.

return contextCreationSucceeded;

}

// All the pinvoke goo...

[DllImport("Kernel32.dll")]

private extern static IntPtr CreateActCtx(ref ACTCTX actctx);

[DllImport("Kernel32.dll")]

private extern static bool ActivateActCtx(IntPtr hActCtx, out uint lpCookie);

[DllImport("Kernel32.dll")]

private extern static bool DeactivateActCtx(uint dwFlags, uint lpCookie);

private const int ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID = 0x004;

private struct ACTCTX

{

public int cbSize;

public uint dwFlags;

public string lpSource;

public ushort wProcessorArchitecture;

public ushort wLangId;

public string lpAssemblyDirectory;

public string lpResourceName;

public string lpApplicationName;

}

Then replace the default Main() with the following wrapper code. This procedure pushes a themed activation context before creating any controls:

            static void Main()
            {
                  using( new EnableThemingInScope( true ) )
                  {
                       Form form1 = new Form();
                       form1.CreateControl();
                       Application.Run(form1);
                  }
            }

...Enjoy !!

Fighting the "InteropServices.SEHException: External component has thrown an exception" blues

Addys — Sat, 14 Aug 2004 02:32:00 GMT

<8/18/2004 update: see part II of this post, with a better solution: http://weblogs.asp.net/asanto/archive/2004/08/18/216825.aspx >

.Net version 1.1 has a bug with XP Visual Styles which causes the following cryptic exception: "'System.Runtime.InteropServices.SEHException: External component has thrown an exception". This exception is trapped in the main application message loop (in a winform this is typically "Application.Run(new Form1());" ) which really doesn't help when trying to debug. It turns out that this is a known bug which has been written up in many a blog: Scott Hanselman, Jeff Key, Aaron Z.

Most blogs recommend either adding a DoEvents() in the code immediately after the EnableVisualStyles() command, or to skip the EnableVisualStyles() altogether and instead use an XML manifest to enable XP themes. The DoEvents() didn't work for me at all (my app still crashed, just a bit deeper inside the UI) and I'm not willing to even think about using an XML manifest.

The solution I came up is:

[STAThread]
static void Main()
{
Application.EnableVisualStyles();
new Thread(new ThreadStart(AppRun)).Start();
}

private static void AppRun()
{
Application.Run(new MainForm());
}

To be honest, this code sort of scares me. It works (so far) but I can't explain exactly why. Help ??!?