Add ability for App Services to register users

AS Tokens are pulled from their respective configs, which are then
checked against when an AS tries to register using
m.login.application_service. If the token exists and the new username is
within their specified namespace, then the user is created as a
password-less user.

Signed-off-by: Andrew Morgan (https://amorgan.xyz) <andrew@amorgan.xyz>

src/github.com/matrix-org/dendrite/clientapi/auth/authtypes/account.go

@@ -20,10 +20,11 @@ import (
 
 // Account represents a Matrix account on this home server.
 type Account struct {
-	UserID     string
-	Localpart  string
-	ServerName gomatrixserverlib.ServerName
-	Profile    *Profile
+	UserID       string
+	Localpart    string
+	ServerName   gomatrixserverlib.ServerName
+	Profile      *Profile
+	AppServiceID string
 	// TODO: Other flags like IsAdmin, IsGuest
 	// TODO: Devices
 	// TODO: Associations (e.g. with application services)

src/github.com/matrix-org/dendrite/clientapi/auth/authtypes/logintypes.go

@@ -5,7 +5,8 @@ type LoginType string
 
 // The relevant login types implemented in Dendrite
 const (
-	LoginTypeDummy        = "m.login.dummy"
-	LoginTypeSharedSecret = "org.matrix.login.shared_secret"
-	LoginTypeRecaptcha    = "m.login.recaptcha"
+	LoginTypeDummy              = "m.login.dummy"
+	LoginTypeSharedSecret       = "org.matrix.login.shared_secret"
+	LoginTypeRecaptcha          = "m.login.recaptcha"
+	LoginTypeApplicationService = "m.login.application_service"
 )

src/github.com/matrix-org/dendrite/clientapi/auth/storage/accounts/accounts_table.go

@@ -32,14 +32,16 @@ CREATE TABLE IF NOT EXISTS account_accounts (
     -- When this account was first created, as a unix timestamp (ms resolution).
     created_ts BIGINT NOT NULL,
     -- The password hash for this account. Can be NULL if this is a passwordless account.
-    password_hash TEXT
+    password_hash TEXT,
+    -- Identifies which Application Service this account belongs to.
+    appservice_id TEXT,
     -- TODO:
-    -- is_guest, is_admin, appservice_id, upgraded_ts, devices, any email reset stuff?
+    -- is_guest, is_admin, upgraded_ts, devices, any email reset stuff?
 );
 `
 
 const insertAccountSQL = "" +
-	"INSERT INTO account_accounts(localpart, created_ts, password_hash) VALUES ($1, $2, $3)"
+	"INSERT INTO account_accounts(localpart, created_ts, password_hash, appservice_id) VALUES ($1, $2, $3, $4)"
 
 const selectAccountByLocalpartSQL = "" +
 	"SELECT localpart FROM account_accounts WHERE localpart = $1"
@@ -78,7 +80,7 @@ func (s *accountsStatements) prepare(db *sql.DB, server gomatrixserverlib.Server
 // this account will be passwordless. Returns an error if this account already exists. Returns the account
 // on success.
 func (s *accountsStatements) insertAccount(
-	ctx context.Context, localpart, hash string,
+	ctx context.Context, localpart, hash, appserviceID string,
 ) (*authtypes.Account, error) {
 	createdTimeMS := time.Now().UnixNano() / 1000000
 	stmt := s.insertAccountStmt
@@ -86,9 +88,10 @@ func (s *accountsStatements) insertAccount(
 		return nil, err
 	}
 	return &authtypes.Account{
-		Localpart:  localpart,
-		UserID:     makeUserID(localpart, s.serverName),
-		ServerName: s.serverName,
+		Localpart:    localpart,
+		UserID:       makeUserID(localpart, s.serverName),
+		ServerName:   s.serverName,
+		AppServiceID: appserviceID,
 	}, nil
 }
 

src/github.com/matrix-org/dendrite/clientapi/auth/storage/accounts/storage.go

@@ -121,11 +121,17 @@ func (d *Database) SetDisplayName(
 // for this account. If no password is supplied, the account will be a passwordless account. If the
 // account already exists, it will return nil, nil.
 func (d *Database) CreateAccount(
-	ctx context.Context, localpart, plaintextPassword string,
+	ctx context.Context, localpart, plaintextPassword, appserviceID string,
 ) (*authtypes.Account, error) {
-	hash, err := hashPassword(plaintextPassword)
-	if err != nil {
-		return nil, err
+	var err error
+
+	// Generate a password hash if this is not a password-less user
+	hash := ""
+	if appserviceID == "" && plaintextPassword != "" {
+		hash, err = hashPassword(plaintextPassword)
+		if err != nil {
+			return nil, err
+		}
 	}
 	if err := d.profiles.insertProfile(ctx, localpart); err != nil {
 		if common.IsUniqueConstraintViolationErr(err) {
@@ -133,7 +139,7 @@ func (d *Database) CreateAccount(
 		}
 		return nil, err
 	}
-	return d.accounts.insertAccount(ctx, localpart, hash)
+	return d.accounts.insertAccount(ctx, localpart, hash, appserviceID)
 }
 
 // SaveMembership saves the user matching a given localpart as a member of a given

src/github.com/matrix-org/dendrite/clientapi/jsonerror/jsonerror.go

@@ -109,6 +109,12 @@ func UserInUse(msg string) *MatrixError {
 	return &MatrixError{"M_USER_IN_USE", msg}
 }
 
+// Exclusive is an error returned when an application service tries to register
+// an username that is outside of its registered namespace
+func Exclusive(msg string) *MatrixError {
+	return &MatrixError{"M_EXCLUSIVE", msg}
+}
+
 // GuestAccessForbidden is an error which is returned when the client is
 // forbidden from accessing a resource as a guest.
 func GuestAccessForbidden(msg string) *MatrixError {

src/github.com/matrix-org/dendrite/clientapi/routing/register.go

@@ -63,7 +63,7 @@ var (
 // remembered. If ANY parameters are supplied, the server should REPLACE all knowledge of
 // previous parameters with the ones supplied. This mean you cannot "build up" request params.
 type registerRequest struct {
-	// registration parameters.
+	// registration parameters
 	Password string `json:"password"`
 	Username string `json:"username"`
 	Admin    bool   `json:"admin"`
@@ -71,6 +71,10 @@ type registerRequest struct {
 	Auth authDict `json:"auth"`
 
 	InitialDisplayName *string `json:"initial_device_display_name"`
+
+	// Application Services place Type in the root of their registration
+	// request, whereas clients place it in the authDict struct.
+	Type authtypes.LoginType `json:"type"`
 }
 
 type authDict struct {
@@ -233,6 +237,95 @@ func validateRecaptcha(
 	return nil
 }
 
+// UsernameIsWithinApplicationServiceNamespace checks to see if a username falls
+// within any of the namespaces of a given Application Service. If no
+// Application Service is given, it will check to see if it matches any
+// Application Service's namespace.
+func UsernameIsWithinApplicationServiceNamespace(
+	cfg *config.Dendrite,
+	username string,
+	appservice *config.ApplicationService,
+) (bool, *util.JSONResponse) {
+	if appservice != nil {
+		// Loop through given Application Service's namespaces and see if any match
+		for _, namespace := range appservice.Namespaces["users"] {
+			match, err := regexp.MatchString(namespace.Regex, username)
+			if err != nil {
+				return false, &util.JSONResponse{
+					Code: 401,
+					JSON: jsonerror.BadJSON("Supplied Application Service namespace" + namespace.Regex + "is invalid."),
+				}
+			}
+			if match {
+				return true, nil
+			}
+		}
+		return false, nil
+	}
+
+	// Loop through all known Application Service's namespaces and see if any match
+	for _, knownAppservice := range cfg.Derived.ApplicationServices {
+		for _, namespace := range knownAppservice.Namespaces["users"] {
+			match, err := regexp.MatchString(namespace.Regex, username)
+			if err != nil {
+				return false, &util.JSONResponse{
+					Code: 401,
+					JSON: jsonerror.BadJSON("Supplied Application Service namespace" + namespace.Regex + "is invalid."),
+				}
+			}
+			if match {
+				return true, nil
+			}
+		}
+	}
+	return false, nil
+}
+
+// validateApplicationService checks if a provided application service token
+// corresponds to one that is registered. If so, then it checks if the desired
+// username is within that application service's namespace. As long as these
+// two requirements are met, no error will be returned.
+func validateApplicationService(
+	cfg *config.Dendrite,
+	req *http.Request,
+	username string,
+) (string, *util.JSONResponse) {
+	// Check if the token if the application service is valid with one we have
+	// registered in the config.
+	accessToken := req.URL.Query().Get("access_token")
+	var matchedApplicationService *config.ApplicationService
+	for _, appservice := range cfg.Derived.ApplicationServices {
+		if appservice.ASToken == accessToken {
+			matchedApplicationService = &appservice
+			break
+		}
+	}
+	if matchedApplicationService != nil {
+		return "", &util.JSONResponse{
+			Code: 401,
+			JSON: jsonerror.BadJSON("Supplied access_token does not match any known application service"),
+		}
+	}
+
+	// Ensure the desired username is within at least one of the application service's namespaces.
+	matched, err := UsernameIsWithinApplicationServiceNamespace(cfg, username, matchedApplicationService)
+	if err != nil {
+		return "", err
+	}
+
+	// If we didn't find any matches, return M_EXCLUSIVE
+	if !matched {
+		return "", &util.JSONResponse{
+			Code: 401,
+			JSON: jsonerror.Exclusive("Supplied username " + username +
+				" did not match any namespaces for application service ID: " + matchedApplicationService.ID),
+		}
+	}
+
+	// No errors, registration valid
+	return matchedApplicationService.ID, nil
+}
+
 // Register processes a /register request. http://matrix.org/speculator/spec/HEAD/client_server/unstable.html#post-matrix-client-unstable-register
 func Register(
 	req *http.Request,
@@ -294,7 +387,6 @@ func handleRegistrationFlow(
 	deviceDB *devices.Database,
 ) util.JSONResponse {
 	// TODO: Shared secret registration (create new user scripts)
-	// TODO: AS API registration
 	// TODO: Enable registration config flag
 	// TODO: Guest account upgrading
 
@@ -331,6 +423,21 @@ func handleRegistrationFlow(
 		// Add SharedSecret to the list of completed registration stages
 		sessions[sessionID] = append(sessions[sessionID], authtypes.LoginTypeSharedSecret)
 
+	case authtypes.LoginTypeApplicationService:
+		// Check Application Service register user request is valid.
+		// The application service's ID is returned if so.
+		appserviceID, err := validateApplicationService(cfg, req, r.Username)
+
+		if err != nil {
+			return *err
+		}
+
+		// If no error, application service was successfully validated.
+		// Don't need to worry about appending to registration stages as
+		// application service registration is entirely separate.
+		return completeRegistration(req.Context(), accountDB, deviceDB,
+			r.Username, "", appserviceID, r.InitialDisplayName)
+
 	case authtypes.LoginTypeDummy:
 		// there is nothing to do
 		// Add Dummy to the list of completed registration stages
@@ -355,7 +462,7 @@ func handleRegistrationFlow(
 	}
 
 	return completeRegistration(req.Context(), accountDB, deviceDB,
-		r.Username, r.Password, r.InitialDisplayName)
+		r.Username, r.Password, "", r.InitialDisplayName)
 }
 
 // LegacyRegister process register requests from the legacy v1 API
@@ -396,10 +503,10 @@ func LegacyRegister(
 			return util.MessageResponse(403, "HMAC incorrect")
 		}
 
-		return completeRegistration(req.Context(), accountDB, deviceDB, r.Username, r.Password, nil)
+		return completeRegistration(req.Context(), accountDB, deviceDB, r.Username, r.Password, "", nil)
 	case authtypes.LoginTypeDummy:
 		// there is nothing to do
-		return completeRegistration(req.Context(), accountDB, deviceDB, r.Username, r.Password, nil)
+		return completeRegistration(req.Context(), accountDB, deviceDB, r.Username, r.Password, "", nil)
 	default:
 		return util.JSONResponse{
 			Code: 501,
@@ -441,7 +548,7 @@ func completeRegistration(
 	ctx context.Context,
 	accountDB *accounts.Database,
 	deviceDB *devices.Database,
-	username, password string,
+	username, password, appserviceID string,
 	displayName *string,
 ) util.JSONResponse {
 	if username == "" {
@@ -450,14 +557,15 @@ func completeRegistration(
 			JSON: jsonerror.BadJSON("missing username"),
 		}
 	}
-	if password == "" {
+	// Blank passwords are only allowed by registered application services
+	if password == "" && appserviceID == "" {
 		return util.JSONResponse{
 			Code: 400,
 			JSON: jsonerror.BadJSON("missing password"),
 		}
 	}
 
-	acc, err := accountDB.CreateAccount(ctx, username, password)
+	acc, err := accountDB.CreateAccount(ctx, username, password, appserviceID)
 	if err != nil {
 		return util.JSONResponse{
 			Code: 500,

src/github.com/matrix-org/dendrite/cmd/create-account/main.go

@@ -69,7 +69,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	account, err := accountDB.CreateAccount(context.Background(), *username, *password)
+	account, err := accountDB.CreateAccount(context.Background(), *username, *password, "")
 	if err != nil {
 		fmt.Println(err.Error())
 		os.Exit(1)

src/github.com/matrix-org/dendrite/common/config/appservice.go

@@ -47,8 +47,9 @@ type ApplicationService struct {
 	Namespaces map[string][]ApplicationServiceNamespace `yaml:"namespaces"`
 }
 
+// loadAppservices iterates through all application service config files
+// and loads their data into the config object for later access.
 func loadAppservices(config *Dendrite) error {
-	// Iterate through and return all the Application Services
 	for _, configPath := range config.ApplicationServices.ConfigFiles {
 		// Create a new application service
 		var appservice ApplicationService
@@ -75,5 +76,18 @@ func loadAppservices(config *Dendrite) error {
 			config.Derived.ApplicationServices, appservice)
 	}
 
+	// Check for any errors in the loaded application services
+	return checkErrors(config)
+}
+
+// checkErrors checks for any configuration errors amongst the loaded
+// application services according to the application service spec.
+func checkErrors(config *Dendrite) error {
+	// TODO: Check that no two app services have the same as_token or id
+
+	// TODO: Check that namespace(s) are valid regex
+
+	// TODO: Check that exclusive namespaces are actually exclusive
+
 	return nil
 }