feat: add userinfo endpoint

configure.sh

@@ -120,7 +120,7 @@ fi
 # Build an intermediate configuration file
 # File format is: <NGINX variable name><space><IdP value>
 #
-jq -r '. | "$oidc_authz_endpoint \(.authorization_endpoint)\n$oidc_token_endpoint \(.token_endpoint)\n$oidc_jwks_uri \(.jwks_uri)"' < /tmp/${COMMAND}_$$_json > /tmp/${COMMAND}_$$_conf
+jq -r '. | "$oidc_authz_endpoint \(.authorization_endpoint)\n$oidc_token_endpoint \(.token_endpoint)\n$oidc_jwks_uri \(.jwks_uri)\n$oidc_userinfo_endpoint \(.userinfo_endpoint)"' < /tmp/${COMMAND}_$$_json > /tmp/${COMMAND}_$$_conf
 
 # Create a random value for HMAC key, adding to the intermediate configuration file
 echo "\$oidc_hmac_key `openssl rand -base64 18`" >> /tmp/${COMMAND}_$$_conf
@@ -178,7 +178,7 @@ fi
 
 # Loop through each configuration variable
 echo "$COMMAND: NOTICE: Configuring $CONFDIR/openid_connect_configuration.conf"
-for OIDC_VAR in \$oidc_authz_endpoint \$oidc_token_endpoint \$oidc_jwt_keyfile \$oidc_hmac_key $CLIENT_ID_VAR $CLIENT_SECRET_VAR $PKCE_ENABLE_VAR; do
+for OIDC_VAR in \$oidc_authz_endpoint \$oidc_token_endpoint \$oidc_jwt_keyfile \$oidc_userinfo_endpoint \$oidc_hmac_key $CLIENT_ID_VAR $CLIENT_SECRET_VAR $PKCE_ENABLE_VAR; do
 	# Pull the configuration value from the intermediate file
 	VALUE=`grep "^$OIDC_VAR " /tmp/${COMMAND}_$$_conf | cut -f2 -d' '`
 	echo -n "$COMMAND: NOTICE:  - $OIDC_VAR ..."

openid_connect.js

@@ -5,7 +5,7 @@
  */
 var newSession = false; // Used by oidcAuth() and validateIdToken()
 
-export default {auth, codeExchange, validateIdToken, logout};
+export default {auth, codeExchange, validateIdToken, logout, userInfo};
 
 function retryOriginalRequest(r) {
     delete r.headersOut["WWW-Authenticate"]; // Remove evidence of original failed auth_jwt
@@ -298,4 +298,39 @@ function idpClientAuth(r) {
     } else {
         return "code=" + r.variables.arg_code + "&client_secret=" + r.variables.oidc_client_secret;
     }   
-}
+}
+
+// Return necessary user info claims after receiving and extracting all claims
+// that are received from the OpenID Connect Provider(OP).
+function userInfo(r) {
+    r.subrequest('/_userinfo',
+        function(res) {
+            if (res.status == 200) {
+                var error_log = "OIDC userinfo JSON failure";
+                var claimsOP = ''; // Claims that are received by the OP.
+                try {
+                    claimsOP = JSON.parse(res.responseBody);
+                } catch (e) {
+                    error_log += ": " + res.responseBody;
+                    r.error(error_log);
+                    r.return(500);
+                    return;
+                }
+                // The claimsRP is to extract claims that are configured in
+                // $oidc_userinfo_required_claims in the RP and send them to
+                // the client using the response of the OP.
+                var claimsRP = r.variables.oidc_userinfo_required_claims.split(",");
+                var ret = {};
+                for (var i in claimsRP) {
+                    if (claimsRP[i] in claimsOP) {
+                        ret[claimsRP[i]] = claimsOP[claimsRP[i]];
+                    }
+                }
+                r.variables.user_info = JSON.stringify(ret);
+                r.return(200, r.variables.user_info);
+            } else {
+                r.return(res.status)
+            }
+        }
+    );
+}

openid_connect.server_conf

@@ -66,6 +66,26 @@
         error_page 500 502 504 @oidc_error;
     }
 
+    location = /userinfo {
+        # This location is to provide signed-in user information claims that are
+        # defined in $oidc_userinfo_required_claims.
+        default_type application/json;
+        if ($oidc_userinfo_required_claims = '') {
+            return 200 '{"name": "", "message":"details not provided per your policy"}';
+        }
+        js_content oidc.userInfo;
+    }
+
+    location = /_userinfo {
+        # This location is called by oidc.userInfo() when calling /userinfo
+        # to get signed-in user information from the OP:
+        # - https://openid.net/specs/openid-connect-core-1_0.html#UserInfo
+        internal;
+        proxy_ssl_server_name on;             # For SNI to the IdP
+        proxy_set_header Authorization "Bearer $access_token";
+        proxy_pass       $oidc_userinfo_endpoint;
+    }
+
     location = /logout {
         status_zone "OIDC logout";
         add_header Set-Cookie "auth_token=; $oidc_cookie_flags"; # Send empty cookie

openid_connect_configuration.conf

@@ -28,6 +28,19 @@ map $host $oidc_jwt_keyfile {
     default "http://127.0.0.1:8080/auth/realms/master/protocol/openid-connect/certs";
 }
 
+map $host $oidc_userinfo_endpoint {
+    default "http://127.0.0.1:8080/auth/realms/master/protocol/openid-connect/userinfo";
+}
+
+map $host $oidc_userinfo_required_claims {
+    # The $oidc_userinfo_endpoint returns OP's response that contains default or
+    # customized claims. This is used for scenarios where the SPA needs to show
+    # user name or specific profiles instead of forwarding the response from the
+    # OP to the SPA to minimize exposure of user info claims.
+    default "";
+    #www.example.com "sub,name,preferred_username,given_name,family_name,email,photo";
+}
+
 map $host $oidc_client {
     default "my-client-id";
 }