Authenticating App with OAuth from C# - c#

I am writing an app that will talk with Salesforce. Salesforce provides access to APIs via OAuth. I've been attempting to go through the OAuth authentication process described here. Currently, I'm attempting to authorize my app. I have the following code.
// Ask Salesforce for a request token
var request = (HttpWebRequest)(WebRequest.Create(String.Format("https://login.salesforce.com/services/oauth2/authorize?response_type=code&client_id={0}&redirect_uri=http://localhost:5004/home/AuthCallback", CONSUMER_KEY)));
request.Method = "POST";
request.ContentType = "application/json";
// Retrieve the request token from the response
var response = (HttpWebResponse)(request.GetResponse());
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
string accessCodeData = accessCodeReader.ReadToEnd();
}
This code is triggered when a user clicks a button in my ASP.NET MVC view. When executed, this code calls to Salesforce. I see a request in fiddler. The request header looks like this:
POST /services/oauth2/authorize?response_type=code&client_id={consumerKey}&redirect_uri=http://localhost:5004/home/AuthCallback HTTP/1.1
I am in fact passing my consumer key, I'm just removing it from the example. Regardless, this request returns a 302, with a body size of 0. I might be misunderstanding something. However, I was expecting to get a request token. I was then going to use the request token to get the access token.
What am I doing wrong?

You are misusing the API.
Take a closer look at the sequence diagram at their page (under Obtaining an Access Token): in the auhorization_code flow you are supposed to redirect the browser to their page so that the user sees the login page, provides his/her credentials and you get the token back. Instead, you are trying to POST there using a web request from your server.
This particular flow belongs then to the passive flows group, this group is intended to be used in browser apps, your server redirects the browser to their server and you basically get the response to the uri passed in the redirect_uri parameter and this should point back to your application at your server.
There are other flows, of them one is suited for non-browser apps, it is called resource owner password flow. In this flow it is your application that hosts the login UI and you send the username/password to the authorization server and you get the token back. It is to be read in their docs however whether this flow is supported.
Read more here: http://aaronparecki.com/articles/2012/07/29/1/oauth2-simplified
Take a look how I handle the OAuth2 flow to Google, using the DotNetOpenAuth library. This is a direct solution, applying it to any other provider should be straightforward.
http://www.wiktorzychla.com/2014/11/simple-oauth2-federated-authentication.html

Related

Postman omits original Oauth2 authentication handshake code

I have a Postman request sent by a partner/client that requires Oauth2 to hit their web service endpoint. Here is the authorization section:
I need to re-create this request in C#. Should be easy, just click on Code link, and grab the sample code in C# - RestSharp. Two problems:
1- When I execute this in Postman, I get The SAML2 token is not valid because its validity period has ended. So then I click the Get New Access Token button, and I get challenged for credentials:
(With the Client ID and Client Secret, shouldn't I be able to bypass this challenge?)
2- Ultimately I need to be able to run this request in my c# app. When I click the Code link in Postman it gives a nice C# example, but the problem with the sample code generated by Postman is that it assumes the bearer token has already been obtained, and just plops that into the source sample. But the obtaining of the bearer token is a very important piece that Postman omits. Here is my specific example, copied from Postman:
var client = new RestClient("https://myurl-here:7148/foo/ODataV4/WS3_stuff?Company='abc123'");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");
request.AddHeader("Authorization", "Bearer ey...massive-string...Zb");
request.AddHeader("Cookie", "ApplicationGatewayAffinity=ab721.more.d6c1a341bc; ApplicationGatewayAffinityCORS=ab..more...bc");
request.AddParameter("application/json", "{a-bunch-of-json-here}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);
What are the pieces I'm missing? How can I get the C# equivalent of whatever Postman is doing to obtain the bearer and those Cookie values? And I thought there's a way for applications to achieve all the Oauth handshaking without sending the user to that MS window as in screenshot above - but how is it done?
ClientID and ClientSecret are there to identify your application not the user. They are sent to the Authorization Server so that the server knows that it can issue access tokens to this application. User authentication is another thing. You will always have to authenticate the user in order to get an access token which allows to access that user's data.
Unless you only need to authenticate your application and want to access data which does not belong to any user. In that case you need a client credentials flow, an OAuth flow which allows your application to get an access token.
Postman is a tool for making calls to APIs, it just generates the code which enables you to make the API call. Have a look at some C# OAuth clients (or maybe something for your framework, if you're using one). Those clients will enable you to easily generate new access tokens. Still, if you need a user's access token remember that you will need your users to open a browser. If you're developing a backend app, which does not serve any pages then you can have a look at the OAuth device flow, which enables you to authenticate users on a different device than your app runs.
As for the cookies - make sure whether you really need them. If you're calling an API chances are that those cookies are not required to make the request.

DocuSign JWT Impersonation Issues

I'm working through the JWT impersonation flows documented here and here. I'm using C#, and though I have worked through a few of the quick start applications, I'm still having some issues.
Existing Flow
The flow I have so far, which seems to be functional in DS sandbox/dev/demo, is:
Send user to DocuSign (oauth/auth). scope is "signature impersonation". (I've tried it with a bunch more permissions thrown in as well.)
After DS auth and impersonation grant, user shows back up on my web app with an authorization code
Take that authorization code and post it to oauth/token to get an access token for my target user
Take that access token and call oauth/userinfo to get the target user's IDs and URL
Create a JWT, sign using shared key pair between my web app and DS, and post it to oauth/token. Receive a 200 response with a seemingly-good-looking token.
This all seems to work correctly so far: all DS calls come back with 200s and data which is shaped as I expect.
Problems
The issue is that I can't actually successfully use that token from the final step to perform further action as the user who my app is impersonating. (I am being sure to use the base_url for the associated user.) When I request a GET from the suggested endpoint (brands), I receive this back:
{
"errorCode": "AUTHORIZATION_INVALID_TOKEN",
"message": "The access token provided is expired, revoked or malformed. Authentication for System Application failed."
}
The response which provided the authorization token includes an expires_in value in the thousands of seconds, and I'm performing all of these requests in serial in my web application. So, expiration or revocation should not be possible at this point. I also haven't touched the token at all, so I would expect it to be well formed.
Here's the code I'm using to post to that endpoint, if it's useful:
private async Task<IgnoreMe> GetBrands(UserInfoAccount account, AccessTokenResponse accessToken)
{
var client = _clientFactory.CreateClient("docusign");
var request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri($"{account.BaseUri}/restapi/v2.1/accounts/{account.Id}/brands"),
};
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken.AccessToken!);
var response = await client.SendAsync(request);
if (!response.IsSuccessStatusCode)
{
return IgnoreMe.Fail;
}
return IgnoreMe.Succeed;
}
The args to this method are the values which came back from previous API calls: the AccessTokenResponse is from the impersonation call.
I've also tried sending similar requests to several other top-level user/account endpoints, and have received the same or similar errors for all of them.
What am I missing here?
Your flow is a mix if Auth Code Grant and JWT. You are using both.
The token from step 3 should work (But you can omit "impersonation" as it's not required for Auth Code Grant).
The token expires after 8 hours. That may be the reason for your error. You'll need to obtain a new one.
In this particular case, the problem was that I had used the wrong ID for the sub value when constructing the JWT.
Results from the oauth/userinfo endpoint I'm using come back structured as a top-level user ID which is associated with a bucket of accounts. I had used an account ID from one of those buckets rather than the top-level user ID.

Dynamics CRM api HttpClient Request Authentication with ADFS 3.0

I have an on-premise Dynamics CRM (2016) that is configured with ADFS (3.0). When a user want's to Login, they get redirected to the ADFS login page and the user enter their Windows AD credentials.
From a .net core application I need to make request to the CRM api using HttpClient. When I try to send the credentials like I normally would for a Windows Auth CRM it doesnt work. I get a 401 Unauthorized. Like below.
HttpClient client = new HttpClient(new HttpClientHandler() { Credentials = new NetworkCredential("myuser", "mypassword", "mydomain") });
var result = client.GetAsync("https://mycrmaddress/api/data/v8.0/accounts");
I also tried using Adal to retrieve a token and attach it as a bearer token to the request but I'm unable to get a token with adal. When I try I receive the following:
The authorization server does not support the requested 'grant_type'. The authorization server only supports 'authorization_code'
ADFS 3.0 doesn't support this flow.
I cannot upgrade to ADFS 4.0 so I would like to know what are my options to make an authenticated call to CRM api (without prompting a login window as this application is a service).
Is there any configuration I can do on ADFS so my first example work? Or is it possible to do it with Adal even if it's ADFS 3.0? Or any other solution...
I found the answer to my question. It's kinda hackish, but I tested it myself and it works. As a temporary solution this will do the trick.
Details are available here: https://community.dynamics.com/crm/f/117/t/255985
ADFS 3.0 supports the Authorization Code flow and this what we will use in this case.
We need to retrieve an authorization code. Normally at this steps a windows is prompted to the user to enter its credentials. By doing a POST and sending the user/password it's possible to retrieve an authorization code.
{authProvider} - ADFS Uri - something like
https://adfs.mycompany.com/adfs/oauth2/
{ClientId} - The Guid used to
by your infrastructure team to add your application to ADFS
{RedirectUri} - The IFD Uri for dynamics - should match the redirect
Url used to by your infrastructure team to add your application to
ADFS
username - The User set up on ADFS and in Dynamics
password - The password for the above user
Then we make the following call with these information using HttpClient.
var uri = $"{authProvider}authorize?response_type=code&client_id={clientId}&resource={redirectUri}&redirect_uri={redirectUri}";
var content = new FormUrlEncodedContent(new[] {
new KeyValuePair<string,string>("username",username),
new KeyValuePair<string,string>("password",password),
});
var responseResult = _httpManager.PostAsync(uri, content).Result;
The response content will be an html page (Remember normally this flow prompts a login page to the user). In this page there will be a form that contains the authorization code. using a library like HtmlAgilityPack retrieve the token. This is the hackish part of the solution.
Now that we have an authorization code we need to retrieve an access token.
For that we need to make the following call
var uri = $"{authProvider}token";
var content = new FormUrlEncodedContent(new[] {
new KeyValuePair<string,string>("grant_type","authorization_code"),
new KeyValuePair<string,string>("client_id",clientId),
new KeyValuePair<string,string>("redirect_uri",redirectUri),
new KeyValuePair<string,string>("code",code)
});
var response = await _httpManager.PostAsync(uri, content);
The response content will be a json string that will contain the access token.
With the access token, make the call to CRM rest API.
You will need to attach the token to the HttpClient in the header as a bearer token.
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer",token);
httpClient.DefaultRequestHeaders.Add("OData-MaxVersion", "4.0");
httpClient.DefaultRequestHeaders.Add("OData-Version", "4.0");
From now on you can make calls to CRM api and you will be authorized. However be carefull normally access token are short lived. You will either need to increase their lifetime or request a new token everytime it's expired.

How to Consume WebApi WebService that Requires Redirect for Login

We have a desktop application that requires authentication with a server in order to operate. This application prepares and sends a query to a webservice, the user is prompted from this webservice to log in and the webservice returns an XML document with application subscription information (Software-as-a-Service Subscription License).
I've created a WebApi webservice that does the following:
Accept incoming request at /api/client?[MACHINEINFOINQUERYSTRING]
Redirect to external authentication provider (think GoogleId or
similar)
Authentication provider sends information back to
/api/subscription/[AUTHENTICATIONID]
The /api/subscription endpoint returns an XML document after pulling info from the servers (or including appropriate error message).
This webservice works and the XML document can be viewed in the browser. I've created a website with a default.aspx to test this, automatically redirecting to the /api/client and it does display this XML document in the browser.
The desktop application properly makes the initial call, redirects through an embedded browser to the login page, and receives an XML, but this XML cannot be parsed. The application team simply gets a "download" option for the XML but cannot capture the response for stuffing into an XmlDocument object. I've attempted to create an example application to instruct the app team, but have had no success.
Questions:
Do I have this architecture fundamentally wrong or do we simply not know how to consume the response properly?
How do I capture and consume the XML that is successfully returned?
As an example of what I've tried:
string requestString = string.Format("http://[server]/api/client?{0}", HttpUtility.HtmlEncode(queryString));
Response.Redirect(requestString);
This works in the browser, displays the login page, allows for input, redirects to the subscription endpoint which then prepares and delivers the XML to the browser. Unfortunately, this is unusable by a consumer.
HttpWebRequest request = WebRequest.Create(requestString) as HttpWebRequest;
request.AllowAutoRedirect = true;
request.MaximumAutomaticRedirections = 20;
request.AuthenticationLevel = System.Net.Security.AuthenticationLevel.None;
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
This doesn't work. The response.ResponseUri has the properly formatted address of the OAuth service (step 2 above). It does not display the login page to the user even though this is all initiated through a browser.
I've also tried using a WebRequest POST, HttpClient PostAsync and several other methods, but:
The response URL is simply the location of the login page. If I string together 3 WebRequest/WebResponse pairs, it fails because the user isn't being properly authenticated at the first request / initial redirect.
What does work in my default.aspx:
I haven't found an example online for my specific needs, but the pattern must exist in practice as plenty of websites utilize OAuth style logins. I've utilized webservices (like OData endpoints) that also require logins, so this pattern must exist for webservices too. I do send back a properly formatted XML document. We just don't know how to capture and consume that document.
Any examples of a similar architecture would be highly appreciated! Or pointing me in the right direction.
Edit ---
I'm thinking that somehow the request.GetResponse() isn't really allowing for redirects and/or since it's an HttpWebRequest, there's no way it will allow for user input.
What's the proper way to make this call and consume the XML from another application? the XML is delivered properly in a browser window (with Response.Redirect) but no login window opens using an HttpWebRequest.
The answer is: This architecture is fundamentally wrong.
OAuth architecture leaves the authorization to the client, which then sends an authorization token to all subsequent services that it requires. The services are simple endpoints and do not contain any authentication logic, (although the service itself is allowed to validate the authentication token with the OAuth server).
The proper sequence of events for this answer should be:
1) Desktop Application makes OAuth authentication request to authentication server.
2) A successful response includes an authorization token which contains identity information, permissions, validity period, etc.
3) The desktop app then requests information from the WebApi service, sending in the request that token.
4) WebApi takes this authentication token, validates it (in my case against a certificate) and may even query the OAuth server again to ensure that the token is still valid.
5) If valid, the web service gathers the data and sends it back to the server.
My problem was I was expecting the subscription service itself to be able to open a web browser, prompt for a login, and then continue the request to another endpoint (2 redirects after initial request). I was in effect, breaking both the WebApi and OAuth 2 designs. Although it worked from the browser, it was not consumable from an application.
After redesigning to this simpler pattern, my web service is now consumable.

How to use OAuth accesstoken to acquire profile images from various providers using DotNetOpenAuth.AspNet and Microsoft.AspNet.Membership.OpenAuth?

I've created a web application that uses the OAuth authentication and universal connectors as explained in this tutorial, and started to fiddle around a little to add support for other providers like Yahoo and LinkedIn. So the authentication part works and users are created in the asp.net Membership provider. Also, all the providers return the accesstoken which I supposedly can use to retrieve more information regarding the user.
I'd really like to acquire the profile image, but it seems every provider has a different way of requesting this information. Twitter even describes a way to authorise every request by changing the HTTP header information.
Whilst reading this information on the websites of the various providers I was wondering whether this functionality isn't also already included somewhere in DotNetOpenAuth.AspNet or Microsoft.AspNet.Membership.OpenAuth implementation.
How can I use DotNetOpenAuth.AspNet and/or Microsoft.AspNet.Membership.OpenAuth to request the profile image of the loggedin user using the just acquired accesstoken?
UPDATE in response to Leo's answer
I use the following code to make a call on LinkedIn's API.
string accessToken = extraData["accesstoken"]; // Extra Data received from OAuth containing the accesstoken.
WebRequest request = WebRequest.Create("https://api.linkedin.com/v1/people/~:(id,first-name,last-name,date-of-birth,email-address,picture-url)?oauth2_access_token=" + accessToken);
using (WebResponse response = request.GetResponse())
{
// do something with response here.
}
Error message is "The remote server returned an error: (401) Unauthorized.".
What am I doing wrong?
The answer is simple...you can't use any of these. These are wrappers of OAuth and OAuth only specifies how you can authenticate a user. Now, to request the user's profile photo you will need to use the external provider's own API and you will need most likely a valid access token. So, you will need to use one of these implementations of OAuth to authenticate a user and the recieve an access token, store the access token somewhere (usually a cookie) and then use the access token to make sub-sequent calls to the provider's APIs. Examples and links....
Facebook's Graph API allows you to retrieve users profiles
https://developers.facebook.com/docs/graph-api/quickstart/
notice that all examples in the link above will require you to include the access token in a parameter named access_token, for example
https://graph.facebook.com/me?method=GET&format=json&suppress_http_code=1&access_token={your-access-token}
Google...
https://www.googleapis.com/oauth2/v3/userinfo?access_token={your-access-token}
LinkedIn...
https://api.linkedin.com/v1/people/~:(id,first-name,last-name,date-of-birth,email-address,picture-url)?oauth2_access_token={your-access-token}
You can get more specific information from these providers' websites
Let me know if you have any other doubts I might be able to help you since I have implemented stuff like these before.
Cheers, Leo

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