Manual Certificate Validation - asp.net

I have an ASP.net Webservice (asmx) which returns some secure stuff from my application. I want to create a client application which uses a certificate to connect to this service and calls this method. Using a certificate I want to ensure only this special client application can call this webservice method.
I've read hundreds of complicated articles how to setup the infrastructure but I quited because of annoying setups and very complicated parts (i.E. certificate store setups,...). I decided to manually do the certificate validation within my service method. This way I know what's going on and I don't have to rely on complicated server setups.
But the question is: How can I do that?
This stubs represent what I want to do:
[WebMethod]
public string GetSecureData() {
if(!ValidateClientCertificate()) {
throw new HttpException((int) (HttpStatusCode.BadRequest), "Bad Request");
}
return "i am secure";
}
private bool ValidateClientCertificate() {
HttpClientCertificate cert = HttpContext.Current.Request.ClientCertificate;
if (!cert.IsPresent || !HttpContext.Current.Request.IsSecureConnection) {
return false;
}
bool isValid = /* is cert the almighty client certificate? */
return isValid;
}
On client side I do something like this:
X509Certificate Cert = X509Certificate.CreateFromCertFile("C:\\secure.cer");
ServicePointManager.CertificatePolicy = new CertPolicy();
HttpWebRequest Request = (HttpWebRequest)WebRequest.Create("https://myserver/Secure.asmx/GetSecureData");
Request.ClientCertificates.Add(Cert);
Request.Method = "GET";
HttpWebResponse Response = (HttpWebResponse)Request.GetResponse();
It would be awesome if I can put some sort of "public key" into the application (App_Data) and check if the client certificate received is the one represented by this public key.
The problems are:
How do I do the magic shown as comment in the first code piece?
I guess the IIS and ASP.net will block the unknown/unverified client certificate. I would need to disable this check for this special service method.
Please don't blame me if the answer is easy and already answered thousands of times. There are thousands of articles about this topic with 100 different solutions and variants. I couldn't find the matching one for my problem.

Related

Widevine DRM Content on Exoplayer 2.0

I am trying to play Widevine encrypted content on an Android TV application using Exoplayer. I have my video URL which is served from a CDN and acquired with a ticket. I have my widevine license URL, a ticket and a auth token for the license server.
I am creating a drmSessionManager, putting the necessary headers needed by the license server as follows:
UUID drmSchemeUuid = C.WIDEVINE_UUID;
mediaDrm = FrameworkMediaDrm.newInstance(drmSchemeUuid);
static final String USER_AGENT = "user-agent";
HttpMediaDrmCallback drmCallback = new HttpMediaDrmCallback("my-license-server", new DefaultHttpDataSourceFactory(USER_AGENT));
keyRequestProperties.put("ticket-header", ticket);
keyRequestProperties.put("token-header", token);
drmCallback.setKeyRequestProperty("ticket-header", ticket);
drmCallback.setKeyRequestProperty("token-header", token);
new DefaultDrmSessionManager(drmSchemeUuid, mediaDrm, drmCallback, keyRequestProperties)
After this Exoplayer handles most of the stuff, the following breakpoints are hit.
response = callback.executeKeyRequest(uuid, (KeyRequest) request);
in class DefaultDrmSession
return executePost(dataSourceFactory, url, request.getData(), requestProperties) in HttpMediaDrmCallback
I can observe that everything is fine till this point, the URL is correct, the headers are set fine.
in the following piece of code, I can observe that the dataSpec is fine, trying to POST a request to the license server with the correct data, but when making the connection the response code returns 405.
in class : DefaultHttpDataSource
in method : public long open(DataSpec dataSpec)
this.dataSpec = dataSpec;
this.bytesRead = 0;
this.bytesSkipped = 0;
transferInitializing(dataSpec);
try {
connection = makeConnection(dataSpec);
} catch (IOException e) {
throw new HttpDataSourceException("Unable to connect to " + dataSpec.uri.toString(), e,
dataSpec, HttpDataSourceException.TYPE_OPEN);
}
try {
responseCode = connection.getResponseCode();
responseMessage = connection.getResponseMessage();
} catch (IOException e) {
closeConnectionQuietly();
throw new HttpDataSourceException("Unable to connect to " + dataSpec.uri.toString(), e,
dataSpec, HttpDataSourceException.TYPE_OPEN);
}
When using postman to make a request to the URL, a GET request returns the following body with a response code of 405.
{
"Message": "The requested resource does not support http method 'GET'." }
a POST request also returns response code 405 but returns an empty body.
In both cases the following header is also returned, which I suppose the request must be accepting GET and POST requests.
Access-Control-Allow-Methods →GET, POST
I have no access to the configuration of the DRM server, and my contacts which are responsible of the DRM server tells me that POST requests must be working fine since there are clients which have managed to get the content to play from the same DRM server.
I am quite confused at the moment and think maybe I am missing some sort of configuration in exoplayer since I am quite new to the concept of DRMs.
Any help would be greatly appreciated.
We figured out the solution. The ticket supplied for the DRM license server was wrong. This works as it is supposed to now and the content is getting played. Just in case anyone somehow gets the same problem or is in need of a basic Widevine content playing code, this works fine at the moment.
Best regards.

Can IIS require SSL client certificates without mapping them to a windows user?

I want to be able to map SSL client certificates to ASP.NET Identity users. I would like IIS to do as much of the work as possible (negotiating the client certificate and perhaps validating that it is signed by a trusted CA), but I don't want IIS to map the certificate to a Windows user. The client certificate is passed through to ASP.NET, where it is inspected and mapped to an ASP.NET Identity user, which is turned into a ClaimsPrincipal.
So far, the only way I have been able to get IIS to pass the client certificate through to ASP.NET is to enable iisClientCertificateMappingAuthentication and set up a many-to-one mapping to a Windows account (which is then never used for anything else.) Is there any way to get IIS to negotiate and pass the certificate through without this configuration step?
You do not have to use the iisClientCertificateMappingAuthentication. The client certificate is accessible in the HttpContext.
var clientCert = HttpContext.Request.ClientCertificate;
Either you enable RequireClientCertificate on the complete site or use a separate login-with-clientcertificate page.
Below is one way of doing this in ASP.NET MVC. Hopefully you can use parts of it to fit your exact situation.
First make sure you are allowed to set the SslFlags in web.config by turning on feature delegation.
Make site accept (but not require) Client Certificates
Set path to login-with-clientcertificate-page where client certificates will be required. In this case a User controller with a CertificateSignin action.
Create a login controller (pseudo-code)
[OutputCache(NoStore = true, Duration = 0, VaryByParam = "*")]
[AllowAnonymous()]
public ActionResult CertificateSignIn()
{
//Get certificate
var clientCert = HttpContext.Request.ClientCertificate;
//Validate certificate
if (!clientCert.IsPresent || !clientCert.IsValid)
{
ViewBag.LoginFailedMessage = "The client certificate was not present or did not pass validation";
return View("Index");
}
//Call your "custom" ClientCertificate --> User mapping method.
string userId;
bool myCertificateMappingParsingResult = Helper.MyCertificateMapping(clientCert, out userId);
if (!myCertificateMappingParsingResult)
{
ViewBag.LoginFailedMessage = "Your client certificate did not map correctly";
}
else
{
//Use custom Membersip provider. Password is not needed!
if (Membership.ValidateUser(userId, null))
{
//Create authentication ticket
FormsAuthentication.SetAuthCookie(userId, false);
Response.Redirect("~/");
}
else
{
ViewBag.LoginFailedMessage = "Login failed!";
}
}
return View("Index");
}

Apache HTTP client 4.3 credentials per request

I have been having a look to a digest authentication example at:
http://hc.apache.org/httpcomponents-client-4.3.x/examples.html
In my scenario the there are several threads issuing HTTP requests and each of them has to be authenticated with their own set of credentials. Additionally, please consider this question is probably very specific for the Apache HTTP client 4.3 onwards, 4.2 handles authentication probably in a different way, although I didn't check it myself. That said, there goes the actual question.
I want to use just one client instance (static member of the class, that is threadsafe) and give it a connection manager to support several concurrent requests. The point is that each request will provide different credentials and I am not seeing the way to assign credentials per request as the credentials provider is set when building the http client. From the link above:
[...]
HttpHost targetHost = new HttpHost("localhost", 80, "http");
CredentialsProvider credsProvider = new BasicCredentialsProvider();
credsProvider.setCredentials(
new AuthScope(targetHost.getHostName(), targetHost.getPort()),
new UsernamePasswordCredentials("username", "password"));
CloseableHttpClient httpclient = HttpClients.custom()
.setDefaultCredentialsProvider(credsProvider).build();
[...]
Checking:
http://hc.apache.org/httpcomponents-client-ga/tutorial/html/authentication.html#d5e600
The code sample in point 4.4 (seek 4.4. HTTP authentication and execution context), seems to say that the HttpClientContext is given the auth cache and the credentials provider and then is passed to the HTTP request. Next to it the request is executed and it seems that the client will get credentials filtering by the host in the HTTP request. In other words: if the context (or the cache) has valid credentials for the target host of the current HTTP request, he will use them. The problem for me is that different threads will perform different requests to the same host.
Is there any way to provide custom credentials per HTTP request?
Thanks in advance for your time! :)
The problem for me is that different threads will perform different requests to the same host.
Why should this be a problem? As long as you use a different HttpContext instance per thread, execution contexts of those threads are going to be completely indepenent
CloseableHttpClient httpclient = HttpClients.createDefault();
CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("user:pass"));
HttpClientContext localContext = HttpClientContext.create();
localContext.setCredentialsProvider(credentialsProvider);
HttpGet httpget = new HttpGet("http://localhost/");
CloseableHttpResponse response = httpclient.execute(httpget, localContext);
try {
EntityUtils.consume(response.getEntity());
} finally {
response.close();
}
I have a similar issue.
I must call n-times a service with a single system user, authenticated with NTLM. I want to do this using multiple threads.
What I came up with is creating a single HTTPClient with no default credential provider. When a request needs to be performed I use an injected CredentialProviderFactory into the method performing the request (in a specific thread). Using this I get a brand new CredentialsProvider and I put this into a Context (created in the thread).
Then I call the execute method on the client using the overload execute(method, context).
class MilestoneBarClient implements IMilestoneBarClient {
private static final Logger log = LoggerFactory.getLogger(MilestoneBarClient.class);
private MilestoneBarBuilder builder;
private CloseableHttpClient httpclient;
private MilestoneBarUriBuilder uriBuilder;
private ICredentialsProviderFactory credsProviderFactory;
MilestoneBarClient(CloseableHttpClient client, ICredentialsProviderFactory credsProviderFactory, MilestoneBarUriBuilder uriBuilder) {
this(client, credsProviderFactory, uriBuilder, new MilestoneBarBuilder());
}
MilestoneBarClient(CloseableHttpClient client, ICredentialsProviderFactory credsProviderFactory, MilestoneBarUriBuilder uriBuilder, MilestoneBarBuilder milestoneBarBuilder) {
this.credsProviderFactory = credsProviderFactory;
this.uriBuilder = uriBuilder;
this.builder = milestoneBarBuilder;
this.httpclient = client;
}
// This method is called by multiple threads
#Override
public MilestoneBar get(String npdNumber) {
log.debug("Asking milestone bar info for {}", npdNumber);
try {
String url = uriBuilder.getPathFor(npdNumber);
log.debug("Building request for URL {}", url);
HttpClientContext localContext = HttpClientContext.create();
localContext.setCredentialsProvider(credsProviderFactory.create());
HttpGet httpGet = new HttpGet(url);
long start = System.currentTimeMillis();
try(CloseableHttpResponse resp = httpclient.execute(httpGet, localContext)){
[...]
For some reasons I sometimes get an error, but I guess it's an NTLMCredentials issue (not being thread-safe...).
In your case, you could probably pass the factory to the get methods instead of passing in creation.

ASP.Net Web API - Authorization header blank

I am having to re-write an existing REST API using .NET (originally written with Ruby). From the client's perspective, it has to work exactly the same way as the old API - i.e. the client code mustn't need to change. The current API requires Basic Authentication. So to call the old API, the following works perfectly:-
var wc = new System.Net.WebClient();
var myCache = new CredentialCache();
myCache.Add(new Uri(url), "Basic", new NetworkCredential("XXX", "XXX"));
wc.Credentials = myCache;
var returnBytes = wc.DownloadData("http://xxxx");
(I have had to ommit the real URL / username / password etc for security reasons).
Now I am writing the new API using ASP.Net Web API with MVC4. I have a weird problem and cannot find anybody else with exactly the same problem. In order to support Basic Authentication, I have followed the guidelines here:
http://sixgun.wordpress.com/2012/02/29/asp-net-web-api-basic-authentication/
One thing, I put the code to "hook in the handler" in the Global.asax.cs file in the Application_Start() event (that wasn't explained so I guessed).
Anyway, if I call my API (which I have deployed in IIS) using the above code, the Authorization header is always null, and the above fails with 401 Unauthorized. However, if I manually set the header using this code, it works fine - i.e. the Authorization header now exists and I am able to Authenticate the user.
private void SetBasicAuthHeader(WebClient request, String userName, String userPassword)
{
string authInfo = userName + ":" + userPassword;
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
request.Headers["Authorization"] = "Basic " + authInfo;
}
.......
var wc = new System.Net.WebClient();
SetBasicAuthHeader(request, "XXXX", "XXXX");
var returnBytes = wc.DownloadData("http://xxxx");
Although that works, it's no good to me because existing users of the existing API are not going to be manually setting the header.
Reading up on how Basic Authentication works, the initial request is meant to be anonymous, then the client is returned 401, then the client is meant to try again. However if I put a break point in my code, it will never hit the code again in Antony's example. I was expecting my breakpoint to be hit twice.
Any ideas how I can get this to work?
You're expecting the right behavior. System.Net.WebClient does not automatically include the Authorization headers upon initial request. It only sends them when properly challenged by a response, which to my knowledge is a 401 status code and a proper WWW-Authenticate header. See here and here for further info.
I'm assuming your basic authentication handler is not returning the WWW-Authenticate header and as such WebClient never even attempts to send the credentials on a second request. You should be able to watch this in Fiddler or a similar tool.
If your handler did something like this, you should witness the WebClient approach working:
//if is not authenticated or Authorization header is null
return base.SendAsync(request, cancellationToken).ContinueWith(task =>
{
var response = task.Result;
response.StatusCode = HttpStatusCode.Unauthorized;
response.Headers.Add("WWW-Authenticate", "Basic realm=\"www.whatever.com\"");
return response;
});
//else (is authenticated)
return base.SendAsync(request, cancellationToken);
As you noticed, if you include the Authorization headers on every request (like you did in your alternative approach) then your handler already works as is. So it may be sufficient - it just isn't for WebClient and other clients that operate in the same way.

WCF Client Proxies, Client/Channel Caching in ASP.Net - Code Review

long time ASP.Net interface developer being asked to learn WCF, looking for some education on more architecture related fronts - as its not my strong suit but I'm having to deal.
In our current ASMX world we adopted a model of creating ServiceManager static classes for our interaction with web services. We're starting to migrate to WCF, attempting to follow the same model. At first I was dealing with performance problems, but I've tweaked a bit and we're running smoothly now, but I'm questioning my tactics. Here's a simplified version (removed error handling, caching, object manipulation, etc.) of what we're doing:
public static class ContentManager
{
private static StoryManagerClient _clientProxy = null;
const string _contentServiceResourceCode = "StorySvc";
// FOR CACHING
const int _getStoriesTTL = 300;
private static Dictionary<string, GetStoriesCacheItem> _getStoriesCache = new Dictionary<string, GetStoriesCacheItem>();
private static ReaderWriterLockSlim _cacheLockStories = new ReaderWriterLockSlim();
public static Story[] GetStories(string categoryGuid)
{
// OMITTED - if category is cached and not expired, return from cache
// get endpoint address from FinderClient (ResourceManagement SVC)
UrlResource ur = FinderClient.GetUrlResource(_contentServiceResourceCode);
// Get proxy
StoryManagerClient svc = GetStoryServiceClient(ur.Url);
// create request params
GetStoriesRequest request = new GetStoriesRequest{}; // SIMPLIFIED
Manifest manifest = new Manifest{}; // SIMPLIFIED
// execute GetStories at WCF service
try
{
GetStoriesResponse response = svc.GetStories(manifest, request);
}
catch (Exception)
{
if (svc.State == CommunicationState.Faulted)
{
svc.Abort();
}
throw;
}
// OMITTED - do stuff with response, cache if needed
// return....
}
internal static StoryManagerClient GetStoryServiceClient(string endpointAddress)
{
if (_clientProxy == null)
_clientProxy = new StoryManagerClient(GetServiceBinding(_contentServiceResourceCode), new EndpointAddress(endpointAddress));
return _clientProxy;
}
public static Binding GetServiceBinding(string bindingSettingName)
{
// uses Finder service to load a binding object - our alternative to definition in web.config
}
public static void PreloadContentServiceClient()
{
// get finder location
UrlResource ur = FinderClient.GetUrlResource(_contentServiceResourceCode);
// preload proxy
GetStoryServiceClient(ur.Url);
}
}
We're running smoothly now with round-trip calls completing in the 100ms range. Creating the PreloadContentServiceClient() method and adding to our global.asax got that "first call" performance down to that same level. And you might want to know we're using the DataContractSerializer, and the "Add Service Reference" method.
I've done a lot of reading on static classes, singletons, shared data contract assemblies, how to use the ChannelFactory pattern and a whole bunch of other things that I could do to our usage model...admittedly, some of its gone over my head. And, like I said, we seem to be running smoothly. I know I'm not seeing the big picture, though. Can someone tell me what I've ended up here with regards to channel pooling, proxy failures, etc. and why I should head down the ChannelFactory path? My gut says to just do it, but my head can't comprehend why...
Thanks!
ChannelFactory is typically used when you aren't using Add Service Reference - you have the contract via a shared assembly not generated via a WSDL. Add Service Reference uses ClientBase which is essentially creating the WCF channel for you behind the scenes.
When you are dealing with REST-ful services, WebChannelFactory provides a service-client like interface based off the shared assembly contract. You can't use Add Service Reference if your service only supports a REST-ful endpoint binding.
The only difference to you is preference - do you need full access the channel for custom behaviors, bindings, etc. or does Add Service Reference + SOAP supply you with enough of an interface for your needs.

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