Reusing ClaimsPrincipal to authenticate against sharepoint online

Question

I have an Office 365 account (using the latest SharePoint 2013 instance)

I also have a simple .net web app that is authenticating against Office 365, I created an AppPrincipalId and added it using New-MsolServicePrincipal powershell commmand.

This works correctly. I launch the app (in debug), it redirects to 365 login, I login, it comes back to the app, and I have derived a class from ClaimsAuthenticationManager and overriden the Authenticate method.

I can now see the ClaimsPrincipal, with the relevant claims and identity etc.

Now I would like to re-use this identity to programmatically access SharePoint.

My questions:

a) Will SharePoint permit this Identity (seeing that it was issued by sts.windows.net)

b) How can I reconstruct a valid JWT (or use the existing one), and encapsulate this in a HttpRequest using authentication bearer.

The code I am using is below - this is coming back 401 not authorized.

Any help would be highly appreciated.

public override ClaimsPrincipal Authenticate(string resourceName, ClaimsPrincipal incomingPrincipal)
    {
        if (incomingPrincipal != null && incomingPrincipal.Identity.IsAuthenticated == true)
        {

            List<Claim> claims = null;
            claims = (from item in incomingPrincipal.Claims
                      where item.Type.StartsWith("http", StringComparison.InvariantCultureIgnoreCase)
                      select item).ToList();

            RNGCryptoServiceProvider cryptoProvider = new RNGCryptoServiceProvider();
            byte[] keyForHmacSha256 = Convert.FromBase64String("Gs8Qc/mAF5seXcGHCUY/kUNELTE=");

            // Create our JWT from the session security token
            JWTSecurityToken jwt = new JWTSecurityToken
            (
                "https://sts.windows.net/myAppIdGuid/",
                "00000003-0000-0ff1-ce00-000000000000", // sharepoint id
                claims,
                new SigningCredentials(
                    new InMemorySymmetricSecurityKey(keyForHmacSha256),
                    "http://www.w3.org/2001/04/xmldsig-more#hmac-sha256",
                    "http://www.w3.org/2001/04/xmlenc#sha256"),
                DateTime.UtcNow,
                 DateTime.UtcNow.AddHours(1)
            );

            var validationParameters = new TokenValidationParameters()
            {
                AllowedAudience = "00000003-0000-0ff1-ce00-000000000000", // sharepoint id
                ValidIssuer = "https://sts.windows.net/myAppIdGuid/", // d3cbe is my app
                ValidateExpiration = true,
                ValidateNotBefore = true,
                ValidateIssuer = true,
                ValidateSignature = true,
                SigningToken = new BinarySecretSecurityToken(Convert.FromBase64String("mySecretKeyFromPowerShellCommand")),
            };

            JWTSecurityTokenHandler jwtHandler = new JWTSecurityTokenHandler();
            var jwtOnWire = jwtHandler.WriteToken(jwt);
            var claimPrincipal = jwtHandler.ValidateToken(jwtOnWire, validationParameters);
            JWTSecurityToken parsedJwt = jwtHandler.ReadToken(jwtOnWire) as JWTSecurityToken;

            HttpWebRequest endpointRequest =
              (HttpWebRequest)HttpWebRequest.Create(
              "https://MySharepointOnlineUrl/_api/web/lists");
                            endpointRequest.Method = "GET";
                            endpointRequest.Accept = "application/json;odata=verbose";
                            endpointRequest.Headers.Add("Authorization",
                              "Bearer " + parsedJwt.RawData);
                            HttpWebResponse endpointResponse =
                              (HttpWebResponse)endpointRequest.GetResponse();

        }
    }

Answer 1

If your scenario is about consuming SharePoint Online data from a remote web app, you probably want to use the OAuth flow. You can't generate the token yourself. Instead you ask for consent to the user to access certain scopes (resource + permission). These two links should help

http://msdn.microsoft.com/en-us/library/office/apps/jj687470(v=office.15).aspx http://jomit.blogspot.com.ar/2013/03/authentication-and-authorization-with.html