Merge pull request #147 from mjcheetham/github-oauthdevice

Enable OAuth device authorisation grant support for GitHub

Author: mjcheetham

src/shared/GitHub/GitHubAuthentication.cs

@@ -61,17 +61,6 @@ public async Task<AuthenticationPromptResult> GetAuthenticationAsync(Uri targetU
         {
             ThrowIfUserInteractionDisabled();
 
-            // If the GitHub auth stack doesn't support flows such as RFC 8628 and we do not have
-            // an interactive desktop session, we cannot offer OAuth authentication.
-            if ((modes & AuthenticationModes.OAuth) != 0
-                && !Context.SessionManager.IsDesktopSession
-                && !GitHubConstants.IsOAuthDeviceAuthSupported)
-            {
-                Context.Trace.WriteLine("Ignoring OAuth authentication mode because we are not in an interactive desktop session. GitHub does not support RFC 8628.");
-
-                modes &= ~AuthenticationModes.OAuth;
-            }
-
             if (modes == AuthenticationModes.None)
             {
                 throw new ArgumentException($"Must specify at least one {nameof(AuthenticationModes)}", nameof(modes));
@@ -211,21 +200,14 @@ public async Task<OAuth2TokenResult> GetOAuthTokenAsync(Uri targetUri, IEnumerab
             {
                 ThrowIfTerminalPromptsDisabled();
 
-                if (GitHubConstants.IsOAuthDeviceAuthSupported)
-                {
-                    OAuth2DeviceCodeResult deviceCodeResult = await oauthClient.GetDeviceCodeAsync(scopes, CancellationToken.None);
-
-                    string deviceMessage = $"To complete authentication please visit {deviceCodeResult.VerificationUri} and enter the following code:" +
-                                           Environment.NewLine +
-                                           deviceCodeResult.UserCode;
-                    Context.Terminal.WriteLine(deviceMessage);
+                OAuth2DeviceCodeResult deviceCodeResult = await oauthClient.GetDeviceCodeAsync(scopes, CancellationToken.None);
 
-                    return await oauthClient.GetTokenByDeviceCodeAsync(deviceCodeResult, CancellationToken.None);
-                }
+                string deviceMessage = $"To complete authentication please visit {deviceCodeResult.VerificationUri} and enter the following code:" +
+                                       Environment.NewLine +
+                                       deviceCodeResult.UserCode;
+                Context.Terminal.WriteLine(deviceMessage);
 
-                // We'd like to try using an OAuth2 flow that does not require a web browser on this device
-                // such as the device code flow (RFC 8628) but GitHub's auth stack does not support this.
-                throw new NotSupportedException("GitHub OAuth authentication is not supported without an interactive desktop session.");
+                return await oauthClient.GetTokenByDeviceCodeAsync(deviceCodeResult, CancellationToken.None);
             }
         }
 

src/shared/GitHub/GitHubConstants.cs

@@ -16,7 +16,7 @@ public static class GitHubConstants
         public static readonly Uri OAuthRedirectUri = new Uri("http://localhost/");
         public static readonly Uri OAuthAuthorizationEndpointRelativeUri = new Uri("/login/oauth/authorize", UriKind.Relative);
         public static readonly Uri OAuthTokenEndpointRelativeUri = new Uri("/login/oauth/access_token", UriKind.Relative);
-        public static readonly Uri OAuthDeviceEndpointRelativeUri = new Uri("/login/oauth/authorize/device", UriKind.Relative);
+        public static readonly Uri OAuthDeviceEndpointRelativeUri = new Uri("/login/device/code", UriKind.Relative);
 
         /// <summary>
         /// The GitHub required HTTP accepts header value
@@ -36,12 +36,6 @@ public static class GitHubConstants
         // TODO: remove Basic once the GCM OAuth app is whitelisted and does not require installation in every organization
         public const AuthenticationModes DotDomAuthenticationModes = AuthenticationModes.Basic | AuthenticationModes.OAuth;
 
-        /// <summary>
-        /// Check if RFC 8628 is supported by GitHub.com and GHE.
-        /// </summary>
-        // TODO: remove this once device auth is supported
-        public const bool IsOAuthDeviceAuthSupported = false;
-
         public static class TokenScopes
         {
             public const string Gist = "gist";

src/shared/GitHub/GitHubOAuth2Client.cs

@@ -17,12 +17,7 @@ private static OAuth2ServerEndpoints CreateEndpoints(Uri baseUri)
         {
             Uri authEndpoint = new Uri(baseUri, GitHubConstants.OAuthAuthorizationEndpointRelativeUri);
             Uri tokenEndpoint = new Uri(baseUri, GitHubConstants.OAuthTokenEndpointRelativeUri);
-
-            Uri deviceAuthEndpoint = null;
-            if (GitHubConstants.IsOAuthDeviceAuthSupported)
-            {
-                deviceAuthEndpoint = new Uri(baseUri, GitHubConstants.OAuthDeviceEndpointRelativeUri);
-            }
+            Uri deviceAuthEndpoint = new Uri(baseUri, GitHubConstants.OAuthDeviceEndpointRelativeUri);
 
             return new OAuth2ServerEndpoints(authEndpoint, tokenEndpoint)
             {