Restrict username length properly
This fixes by fixing the username check to comply with the [spec appendices](https://spec.matrix.org/v1.3/appendices/#user-identifiers):
> The length of a user ID, including the @ sigil and the domain, MUST NOT exceed 255 characters.
MODIFY
clientapi/routing/register.go
clientapi/routing/register.go
@@ -276,19 +276,19 @@ type recaptchaResponse struct {
}
// validateUsername returns an error response if the username is invalid
-func validateUsername(username string) *util.JSONResponse {
+func validateUsername(localpart string, domain gomatrixserverlib.ServerName) *util.JSONResponse {
// https://github.com/matrix-org/synapse/blob/v0.20.0/synapse/rest/client/v2_alpha/register.py#L161
- if len(username) > maxUsernameLength {
+ if id := fmt.Sprintf("@%s:%s", localpart, domain); len(id) > maxUsernameLength {
return &util.JSONResponse{
Code: http.StatusBadRequest,
- JSON: jsonerror.BadJSON(fmt.Sprintf("'username' >%d characters", maxUsernameLength)),
+ JSON: jsonerror.BadJSON(fmt.Sprintf("%q exceeds the maximum length of %d characters", id, maxUsernameLength)),
}
- } else if !validUsernameRegex.MatchString(username) {
+ } else if !validUsernameRegex.MatchString(localpart) {
return &util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.InvalidUsername("Username can only contain characters a-z, 0-9, or '_-./='"),
}
- } else if username[0] == '_' { // Regex checks its not a zero length string
+ } else if localpart[0] == '_' { // Regex checks its not a zero length string
return &util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.InvalidUsername("Username cannot start with a '_'"),
@@ -298,13 +298,13 @@ func validateUsername(username string) *util.JSONResponse {
}
// validateApplicationServiceUsername returns an error response if the username is invalid for an application service
-func validateApplicationServiceUsername(username string) *util.JSONResponse {
- if len(username) > maxUsernameLength {
+func validateApplicationServiceUsername(localpart string, domain gomatrixserverlib.ServerName) *util.JSONResponse {
+ if id := fmt.Sprintf("@%s:%s", localpart, domain); len(id) > maxUsernameLength {
return &util.JSONResponse{
Code: http.StatusBadRequest,
- JSON: jsonerror.BadJSON(fmt.Sprintf("'username' >%d characters", maxUsernameLength)),
+ JSON: jsonerror.BadJSON(fmt.Sprintf("%q exceeds the maximum length of %d characters", id, maxUsernameLength)),
}
- } else if !validUsernameRegex.MatchString(username) {
+ } else if !validUsernameRegex.MatchString(localpart) {
return &util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.InvalidUsername("Username can only contain characters a-z, 0-9, or '_-./='"),
@@ -523,7 +523,7 @@ func validateApplicationService(
}
// Check username application service is trying to register is valid
- if err := validateApplicationServiceUsername(username); err != nil {
+ if err := validateApplicationServiceUsername(username, cfg.Matrix.ServerName); err != nil {
return "", err
}
@@ -604,7 +604,7 @@ func Register(
case r.Type == authtypes.LoginTypeApplicationService && accessTokenErr == nil:
// Spec-compliant case (the access_token is specified and the login type
// is correctly set, so it's an appservice registration)
- if resErr := validateApplicationServiceUsername(r.Username); resErr != nil {
+ if resErr := validateApplicationServiceUsername(r.Username, cfg.Matrix.ServerName); resErr != nil {
return *resErr
}
case accessTokenErr == nil:
@@ -617,7 +617,7 @@ func Register(
default:
// Spec-compliant case (neither the access_token nor the login type are
// specified, so it's a normal user registration)
- if resErr := validateUsername(r.Username); resErr != nil {
+ if resErr := validateUsername(r.Username, cfg.Matrix.ServerName); resErr != nil {
return *resErr
}
}
@@ -1018,7 +1018,7 @@ func RegisterAvailable(
// Squash username to all lowercase letters
username = strings.ToLower(username)
- if err := validateUsername(username); err != nil {
+ if err := validateUsername(username, cfg.Matrix.ServerName); err != nil {
return *err
}
@@ -1059,7 +1059,7 @@ func RegisterAvailable(
}
}
-func handleSharedSecretRegistration(userAPI userapi.ClientUserAPI, sr *SharedSecretRegistration, req *http.Request) util.JSONResponse {
+func handleSharedSecretRegistration(cfg *config.ClientAPI, userAPI userapi.ClientUserAPI, sr *SharedSecretRegistration, req *http.Request) util.JSONResponse {
ssrr, err := NewSharedSecretRegistrationRequest(req.Body)
if err != nil {
return util.JSONResponse{
@@ -1080,7 +1080,7 @@ func handleSharedSecretRegistration(userAPI userapi.ClientUserAPI, sr *SharedSec
// downcase capitals
ssrr.User = strings.ToLower(ssrr.User)
- if resErr := validateUsername(ssrr.User); resErr != nil {
+ if resErr := validateUsername(ssrr.User, cfg.Matrix.ServerName); resErr != nil {
return *resErr
}
if resErr := validatePassword(ssrr.Password); resErr != nil {

MODIFY
clientapi/routing/routing.go
clientapi/routing/routing.go
@@ -133,7 +133,7 @@ func Setup(
}
}
if req.Method == http.MethodPost {
- return handleSharedSecretRegistration(userAPI, sr, req)
+ return handleSharedSecretRegistration(cfg, userAPI, sr, req)
}
return util.JSONResponse{
Code: http.StatusMethodNotAllowed,

Restrict username length properly (#2676)

This fixes #2674 by fixing the username check to comply with the [spec appendices](https://spec.matrix.org/v1.3/appendices/#user-identifiers):

> The length of a user ID, including the @ sigil and the domain, MUST NOT exceed 255 characters.