LoginToken and SSO Login initial changes

Database level changes not made

clientapi/auth/login_token.go

@@ -0,0 +1,209 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/clientapi/userutil"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+// This file handles all the m.login.token logic
+
+// GetAccountByLocalpart function implemented by the appropriate database type
+type GetAccountByLocalpart func(ctx context.Context, localpart string) (*api.Account, error)
+
+// LoginTokenRequest struct to hold the possible parameters from an m.login.token http request
+type LoginTokenRequest struct {
+	Login
+	Token string `json:"token"`
+	TxnID string `json:"txn_id"`
+}
+
+// LoginTypeToken holds the configs and the appropriate GetAccountByLocalpart function for the database
+type LoginTypeToken struct {
+	GetAccountByLocalpart GetAccountByLocalpart
+	Config                *config.ClientAPI
+}
+
+// Name returns the expected type of "m.login.token"
+func (t *LoginTypeToken) Name() string {
+	return "m.login.token"
+}
+
+// Request returns a struct of type LoginTokenRequest
+func (t *LoginTypeToken) Request() interface{} {
+	return &LoginTokenRequest{}
+}
+
+// Type of the LoginToken
+type loginToken struct {
+	UserID       string
+	CreationTime int64
+	RandomPart   string
+}
+
+// Login completes the whole token validation, user verification for m.login.token
+// returns a struct of type *auth.Login which has the users details
+func (t *LoginTypeToken) Login(ctx context.Context, req interface{}) (*Login, *util.JSONResponse) {
+	r := req.(*LoginTokenRequest)
+	userID, err := validateLoginToken(r.Token, r.TxnID, &t.Config.Matrix.ServerName)
+	if err != nil {
+		return nil, &util.JSONResponse{
+			Code: http.StatusUnauthorized,
+			JSON: jsonerror.InvalidArgumentValue(err.Error()),
+		}
+	}
+	r.Login.Identifier.User = userID
+	r.Login.Identifier.Type = "m.id.user"
+
+	return &r.Login, nil
+}
+
+// Decodes and validates a LoginToken
+// Accepts the base64 encoded token string as param
+// Checks the time expiry, userID (only the format, doesn't check to see if the user exists)
+// Also checks the DB to see if the token exists
+// Returns the localpart if successful
+func validateLoginToken(tokenStr string, txnID string, serverName *gomatrixserverlib.ServerName) (string, error) {
+	token, err := decodeLoginToken(tokenStr)
+	if err != nil {
+		return "", err
+	}
+
+	// check whether the token has a valid time.
+	// TODO: should this 5 second window be configurable?
+	if time.Now().Unix()-token.CreationTime > 5 {
+		return "", errors.New("Token has expired")
+	}
+
+	// check whether the UserID is malformed
+	if !strings.Contains(token.UserID, "@") {
+		// TODO: should we reveal details about the error with the token or give vague responses instead?
+		return "", errors.New("Invalid UserID")
+	}
+	if _, err := userutil.ParseUsernameParam(token.UserID, serverName); err != nil {
+		return "", err
+	}
+
+	// check in the database
+	if err := checkDBToken(tokenStr, txnID); err != nil {
+		return "", err
+	}
+
+	return token.UserID, nil
+}
+
+// GenerateLoginToken creates a login token which is a base64 encoded string of (userID+time+random)
+// returns an error if it cannot create a random string
+func GenerateLoginToken(userID string) (string, error) {
+	// the time of token creation
+	timePart := []byte(strconv.FormatInt(time.Now().Unix(), 10))
+
+	// the random part of the token
+	randPart := make([]byte, 10)
+	if _, err := rand.Read(randPart); err != nil {
+		return "", err
+	}
+
+	// url-safe no padding
+	return base64.RawURLEncoding.EncodeToString([]byte(userID)) + "." + base64.RawURLEncoding.EncodeToString(timePart) + "." + base64.RawURLEncoding.EncodeToString(randPart), nil
+}
+
+// Decodes the given tokenStr into a LoginToken struct
+func decodeLoginToken(tokenStr string) (*loginToken, error) {
+	// split the string into it's constituent parts
+	strParts := strings.Split(tokenStr, ".")
+	if len(strParts) != 3 {
+		return nil, errors.New("Malformed token string")
+	}
+
+	var token loginToken
+	// decode each of the strParts
+	userBytes, err := base64.RawURLEncoding.DecodeString(strParts[0])
+	if err != nil {
+		return nil, errors.New("Invalid user ID")
+	}
+	token.UserID = string(userBytes)
+
+	// first decode the time to a string
+	timeBytes, err := base64.RawURLEncoding.DecodeString(strParts[1])
+	if err != nil {
+		return nil, errors.New("Invalid creation time")
+	}
+	// now convert the string to an integer
+	creationTime, err := strconv.ParseInt(string(timeBytes), 10, 64)
+	if err != nil {
+		return nil, errors.New("Invalid creation time")
+	}
+	token.CreationTime = creationTime
+
+	randomBytes, err := base64.RawURLEncoding.DecodeString(strParts[2])
+	if err != nil {
+		return nil, errors.New("Invalid random part")
+	}
+	token.UserID = string(randomBytes)
+
+	token = loginToken{
+		UserID:       string(userBytes),
+		CreationTime: creationTime,
+		RandomPart:   string(randomBytes),
+	}
+	return &token, nil
+}
+
+// Checks whether the token exists in the DB and whether the token is assigned to the current transaction ID
+// Does not validate the userID or the creation time expiry
+// Returns nil if successful
+func checkDBToken(tokenStr string, txnID string) error {
+	// if the client has provided a transaction id, try to lock the token to that ID
+	if txnID != "" {
+		if err := LinkToken(tokenStr, txnID); err != nil {
+			// TODO: should we abort the login attempt or something else?
+		}
+	}
+	return nil
+}
+
+// StoreLoginToken stores the login token in the database
+// Returns nil if successful
+func StoreLoginToken(tokenStr string) error {
+	return nil
+}
+
+// DeleteLoginToken Deletes a token from the DB
+// used to delete a token that has already been used
+// Returns nil if successful
+func DeleteLoginToken(tokenStr string) error {
+	return nil
+}
+
+// LinkToken Links a token to a transaction ID so no other client can try to login using that token
+// as specified in https://matrix.org/docs/spec/client_server/r0.6.1#token-based
+func LinkToken(tokenStr string, txnID string) error {
+	return nil
+}

clientapi/routing/login.go

@@ -15,7 +15,10 @@
 package routing
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
+	"io/ioutil"
 	"net/http"
 
 	"github.com/matrix-org/dendrite/clientapi/auth"
@@ -53,6 +56,15 @@ func passwordLogin() flows {
 	return f
 }
 
+func ssoLogin() flows {
+	f := flows{}
+	s := flow{
+		Type: "m.login.sso",
+	}
+	f.Flows = append(f.Flows, s)
+	return f
+}
+
 // Login implements GET and POST /login
 func Login(
 	req *http.Request, accountDB accounts.Database, userAPI userapi.UserInternalAPI,
@@ -60,33 +72,104 @@ func Login(
 ) util.JSONResponse {
 	if req.Method == http.MethodGet {
 		// TODO: support other forms of login other than password, depending on config options
+		flows := passwordLogin()
+		if cfg.CAS.Enabled {
+			flows.Flows = append(flows.Flows, ssoLogin().Flows...)
+		}
 		return util.JSONResponse{
 			Code: http.StatusOK,
-			JSON: passwordLogin(),
+			JSON: flows,
 		}
 	} else if req.Method == http.MethodPost {
-		typePassword := auth.LoginTypePassword{
-			GetAccountByPassword: accountDB.GetAccountByPassword,
-			Config:               cfg,
+		// TODO: is the the right way to read the body and re-add it?
+		body, err := ioutil.ReadAll(req.Body)
+		if err != nil {
+			// TODO: is this appropriate?
+			return util.JSONResponse{
+				Code: http.StatusMethodNotAllowed,
+				JSON: jsonerror.NotFound("Bad method"),
+			}
 		}
-		r := typePassword.Request()
-		resErr := httputil.UnmarshalJSONRequest(req, r)
-		if resErr != nil {
-			return *resErr
+		// add the body back to the request because ioutil.ReadAll consumes the body
+		req.Body = ioutil.NopCloser(bytes.NewBuffer(body))
+
+		// marshall the body into an unstructured json map
+		var jsonBody map[string]interface{}
+		if err := json.Unmarshal([]byte(body), &jsonBody); err != nil {
+			return util.JSONResponse{
+				Code: http.StatusMethodNotAllowed,
+				JSON: jsonerror.NotFound("Bad method"),
+			}
 		}
-		login, authErr := typePassword.Login(req.Context(), r)
-		if authErr != nil {
-			return *authErr
+
+		loginType := jsonBody["type"].(string)
+		if loginType == "m.login.password" {
+			return doPasswordLogin(req, accountDB, userAPI, cfg)
+		} else if loginType == "m.login.token" {
+			return doTokenLogin(req, accountDB, userAPI, cfg)
 		}
-		// make a device/access token
-		return completeAuth(req.Context(), cfg.Matrix.ServerName, userAPI, login)
 	}
+
 	return util.JSONResponse{
 		Code: http.StatusMethodNotAllowed,
 		JSON: jsonerror.NotFound("Bad method"),
 	}
 }
 
+// Handles a m.login.password login type request
+func doPasswordLogin(
+	req *http.Request, accountDB accounts.Database, userAPI userapi.UserInternalAPI,
+	cfg *config.ClientAPI,
+) util.JSONResponse {
+	typePassword := auth.LoginTypePassword{
+		GetAccountByPassword: accountDB.GetAccountByPassword,
+		Config:               cfg,
+	}
+	r := typePassword.Request()
+	resErr := httputil.UnmarshalJSONRequest(req, r)
+	if resErr != nil {
+		return *resErr
+	}
+	login, authErr := typePassword.Login(req.Context(), r)
+	if authErr != nil {
+		return *authErr
+	}
+
+	// make a device/access token
+	return completeAuth(req.Context(), cfg.Matrix.ServerName, userAPI, login)
+}
+
+// Handles a m.login.token login type request
+func doTokenLogin(req *http.Request, accountDB accounts.Database, userAPI userapi.UserInternalAPI,
+	cfg *config.ClientAPI,
+) util.JSONResponse {
+	// create a struct with the appropriate DB(postgres/sqlite) function and the configs
+	typeToken := auth.LoginTypeToken{
+		GetAccountByLocalpart: accountDB.GetAccountByLocalpart,
+		Config:                cfg,
+	}
+	r := typeToken.Request()
+	resErr := httputil.UnmarshalJSONRequest(req, r)
+	if resErr != nil {
+		return *resErr
+	}
+	login, authErr := typeToken.Login(req.Context(), r)
+	if authErr != nil {
+		return *authErr
+	}
+
+	// make a device/access token
+	authResult := completeAuth(req.Context(), cfg.Matrix.ServerName, userAPI, login)
+
+	// the login is successful, delete the login token before returning the access token to the client
+	if authResult.Code == http.StatusOK {
+		if err := auth.DeleteLoginToken(r.(*auth.LoginTokenRequest).Token); err != nil {
+			// TODO: what to do here?
+		}
+	}
+	return authResult
+}
+
 func completeAuth(
 	ctx context.Context, serverName gomatrixserverlib.ServerName, userAPI userapi.UserInternalAPI, login *auth.Login,
 ) util.JSONResponse {

clientapi/routing/routing.go

@@ -446,6 +446,12 @@ func Setup(
 		}),
 	).Methods(http.MethodGet, http.MethodPost, http.MethodOptions)
 
+	r0mux.Handle("/login/sso/redirect",
+		httputil.MakeExternalAPI("login", func(req *http.Request) util.JSONResponse {
+			return SSORedirect(req, accountDB, cfg)
+		}),
+	).Methods(http.MethodGet, http.MethodOptions)
+
 	r0mux.Handle("/auth/{authType}/fallback/web",
 		httputil.MakeHTMLAPI("auth_fallback", func(w http.ResponseWriter, req *http.Request) *util.JSONResponse {
 			vars := mux.Vars(req)

clientapi/routing/sso.go

@@ -0,0 +1,218 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package routing
+
+import (
+	"encoding/xml"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+
+	"github.com/matrix-org/dendrite/clientapi/auth"
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/userapi/storage/accounts"
+	"github.com/matrix-org/util"
+)
+
+// the XML response structure of CAS ticket validation
+type casValidateResponse struct {
+	XMLName               xml.Name `xml:"serviceResponse"`
+	Cas                   string   `xml:"cas,attr"`
+	AuthenticationSuccess struct {
+		User string `xml:"user"`
+	} `xml:"authenticationSuccess"`
+}
+
+// SSORedirect implements GET /login/sso/redirect
+// https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-login-sso-redirect
+// If the incoming request doesn't contain a SSO token, it will redirect to the SSO server
+// Else it will validate the SSO token, and redirect to the "redirectURL" provided with an extra "loginToken" param
+func SSORedirect(
+	req *http.Request,
+	accountDB accounts.Database,
+	cfg *config.ClientAPI,
+) util.JSONResponse {
+	// If dendrite is not configured to use SSO by the admin return bad method
+	if !cfg.CAS.Enabled || cfg.CAS.Server == "" {
+		return util.JSONResponse{
+			Code: http.StatusMethodNotAllowed,
+			JSON: jsonerror.NotFound("Bad method"),
+		}
+	}
+
+	// Try to parse the SSO URL configured to a url.URL type
+	ssoURL, err := url.Parse(cfg.CAS.Server)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.Unknown("Failed to parse SSO URL configured: " + err.Error()),
+		}
+	}
+
+	// A redirect URL is required for this endpoint
+	redirectURLStr := req.FormValue("redirectUrl")
+	if redirectURLStr == "" {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.MissingArgument("redirectUrl parameter missing"),
+		}
+	}
+	// Check if the redirect url is a valid URL
+	redirectURL, err := url.Parse(redirectURLStr)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.Unknown("Invalid redirectURL: " + err.Error()),
+		}
+	}
+
+	// If the request has a ticket param, validate the ticket instead of redirecting to SSO server
+	if ticket := req.FormValue("ticket"); ticket != "" {
+		return ssoTicket(req, redirectURL, accountDB, cfg)
+	}
+
+	// Adding the params to the sso url
+	ssoQueries := make(url.Values)
+	// the service url that we send to CAS is homeserver.com/_matrix/client/r0/login/sso/redirect?redirectUrl=xyz
+	ssoQueries.Set("service", req.RequestURI)
+
+	ssoURL.RawQuery = ssoQueries.Encode()
+
+	return util.RedirectResponse(ssoURL.String())
+}
+
+// ssoTicket handles the m.login.sso login attempt after the user had completed auth at the SSO server
+// - gets the ticket from the SSO server (this is different from the matrix login/access token)
+// - calls validateTicket to validate the ticket
+// - calls completeSSOAuth
+func ssoTicket(
+	req *http.Request,
+	redirectURL *url.URL,
+	accountDB accounts.Database,
+	cfg *config.ClientAPI,
+) util.JSONResponse {
+	// form the ticket validation URL from the config
+	ssoURL, err := url.Parse(cfg.CAS.Server + cfg.CAS.ValidateEndpoint)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.Unknown("Failed to parse SSO URL configured: " + err.Error()),
+		}
+	}
+
+	ticket := req.FormValue("ticket")
+
+	// append required params to the CAS validate endpoint
+	ssoQueries := make(url.Values)
+	ssoQueries.Set("ticket", ticket)
+	ssoURL.RawQuery = ssoQueries.Encode()
+
+	// validate the ticket
+	casUsername, err := validateTicket(ssoURL.String())
+	if err != nil {
+		// TODO: should I be logging these? What else should I log?
+		util.GetLogger(req.Context()).WithError(err).Error("CAS SSO ticket validation failed")
+		return util.JSONResponse{
+			Code: http.StatusUnauthorized,
+			JSON: jsonerror.Unknown("Could not validate SSO token: " + err.Error()),
+		}
+	}
+	if casUsername == "" {
+		util.GetLogger(req.Context()).WithError(err).Error("CAS SSO returned no user")
+		return util.JSONResponse{
+			Code: http.StatusUnauthorized,
+			JSON: jsonerror.Unknown("CAS SSO returned no user"),
+		}
+	}
+
+	// ticket validated. Login the user
+	return completeSSOAuth(req, casUsername, redirectURL, accountDB)
+}
+
+// validateTicket sends the ticket to the sso server to get it validated
+// the CAS server responds with an xml which contains the username
+// validateTicket returns the SSO User
+func validateTicket(
+	ssoURL string,
+) (string, error) {
+	// make the call to the sso server to validate
+	response, err := http.Get(ssoURL)
+	if err != nil {
+		return "", err
+	}
+
+	// extract the response from the sso server
+	data, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return "", err
+	}
+
+	// parse the response to the CAS XML format
+	var res casValidateResponse
+	if err := xml.Unmarshal([]byte(data), &res); err != nil {
+		return "", err
+	}
+
+	return res.AuthenticationSuccess.User, nil
+}
+
+// completeSSOAuth completes the SSO auth and returns a m.login.token for the client to authenticate with
+// if the user doesn't exist, a new user is created
+func completeSSOAuth(
+	req *http.Request,
+	username string,
+	redirectURL *url.URL,
+	accountDB accounts.Database,
+) util.JSONResponse {
+	// try to create an account with that username
+	// if the user exists, then we pick that user, else we create a new user
+	account, err := accountDB.CreateAccount(req.Context(), username, "", "")
+	if err != nil {
+		// some error
+		if err != sqlutil.ErrUserExists {
+			return util.JSONResponse{
+				Code: http.StatusUnauthorized,
+				JSON: jsonerror.Unknown("Could not create new user"),
+			}
+		} else {
+			// user already exists, so just pick up their details
+			account, err = accountDB.GetAccountByLocalpart(req.Context(), username)
+			if err != nil {
+				return util.JSONResponse{
+					Code: http.StatusUnauthorized,
+					JSON: jsonerror.Unknown("Could not query user"),
+				}
+			}
+		}
+	}
+	token, err := auth.GenerateLoginToken(account.UserID)
+	if err != nil || token == "" {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.Unknown("Could not generate login token"),
+		}
+	}
+
+	// add the params to the sso url
+	redirectQueries := make(url.Values)
+	// the service url that we send to CAS is homeserver.com/_matrix/client/r0/login/sso/redirect?redirectUrl=xyz
+	redirectQueries.Set("loginToken", token)
+
+	redirectURL.RawQuery = redirectQueries.Encode()
+
+	return util.RedirectResponse(redirectURL.String())
+}

internal/config/config_clientapi.go

@@ -32,6 +32,9 @@ type ClientAPI struct {
 	// was successful
 	RecaptchaSiteVerifyAPI string `yaml:"recaptcha_siteverify_api"`
 
+	// CAS server settings
+	CAS CAS `yaml:"cas"`
+
 	// TURN options
 	TURN TURN `yaml:"turn"`
 
@@ -51,6 +54,7 @@ func (c *ClientAPI) Defaults() {
 	c.RecaptchaSiteVerifyAPI = ""
 	c.RegistrationDisabled = false
 	c.RateLimiting.Defaults()
+	c.CAS.Enabled = false
 }
 
 func (c *ClientAPI) Verify(configErrs *ConfigErrors, isMonolith bool) {
@@ -64,10 +68,24 @@ func (c *ClientAPI) Verify(configErrs *ConfigErrors, isMonolith bool) {
 		checkNotEmpty(configErrs, "client_api.recaptcha_private_key", string(c.RecaptchaPrivateKey))
 		checkNotEmpty(configErrs, "client_api.recaptcha_siteverify_api", string(c.RecaptchaSiteVerifyAPI))
 	}
+	c.CAS.Verify(configErrs)
 	c.TURN.Verify(configErrs)
 	c.RateLimiting.Verify(configErrs)
 }
 
+type CAS struct {
+	Enabled          bool   `yaml:"cas_enabled"`
+	Server           string `yaml:"cas_server"`
+	ValidateEndpoint string `yaml:"cas_validate_endpoint"`
+}
+
+func (cas *CAS) Verify(ConfigErrors *ConfigErrors) {
+	if cas.Enabled {
+		checkURL(ConfigErrors, "client_api.cas.cas_server", cas.Server)
+		checkNotEmpty(ConfigErrors, "client_api.cas.cas_validate_endpoint", cas.ValidateEndpoint)
+	}
+}
+
 type TURN struct {
 	// TODO Guest Support
 	// Whether or not guests can request TURN credentials