auth, etcdserver: forbid adding a user with empty name

auth/store.go

@@ -47,6 +47,7 @@ var (
 	ErrRootUserNotExist     = errors.New("auth: root user does not exist")
 	ErrRootRoleNotExist     = errors.New("auth: root user does not have root role")
 	ErrUserAlreadyExist     = errors.New("auth: user already exists")
+	ErrUserEmpty            = errors.New("auth: user name is empty")
 	ErrUserNotFound         = errors.New("auth: user not found")
 	ErrRoleAlreadyExist     = errors.New("auth: role already exists")
 	ErrRoleNotFound         = errors.New("auth: role not found")
@@ -282,6 +283,10 @@ func (as *authStore) Recover(be backend.Backend) {
 }
 
 func (as *authStore) UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	if len(r.Name) == 0 {
+		return nil, ErrUserEmpty
+	}
+
 	hashed, err := bcrypt.GenerateFromPassword([]byte(r.Password), BcryptCost)
 	if err != nil {
 		plog.Errorf("failed to hash password: %s", err)

auth/store_test.go

@@ -46,6 +46,12 @@ func TestUserAdd(t *testing.T) {
 	if err != ErrUserAlreadyExist {
 		t.Fatalf("expected %v, got %v", ErrUserAlreadyExist, err)
 	}
+
+	ua = &pb.AuthUserAddRequest{Name: ""}
+	_, err = as.UserAdd(ua) // add a user with empty name
+	if err != ErrUserEmpty {
+		t.Fatal(err)
+	}
 }
 
 func enableAuthAndCreateRoot(as *authStore) error {

etcdserver/api/v3rpc/rpctypes/error.go

@@ -42,6 +42,7 @@ var (
 	ErrGRPCRootUserNotExist     = grpc.Errorf(codes.FailedPrecondition, "etcdserver: root user does not exist")
 	ErrGRPCRootRoleNotExist     = grpc.Errorf(codes.FailedPrecondition, "etcdserver: root user does not have root role")
 	ErrGRPCUserAlreadyExist     = grpc.Errorf(codes.FailedPrecondition, "etcdserver: user name already exists")
+	ErrGRPCUserEmpty            = grpc.Errorf(codes.InvalidArgument, "etcdserver: user name is empty")
 	ErrGRPCUserNotFound         = grpc.Errorf(codes.FailedPrecondition, "etcdserver: user name not found")
 	ErrGRPCRoleAlreadyExist     = grpc.Errorf(codes.FailedPrecondition, "etcdserver: role name already exists")
 	ErrGRPCRoleNotFound         = grpc.Errorf(codes.FailedPrecondition, "etcdserver: role name not found")
@@ -80,6 +81,7 @@ var (
 		grpc.ErrorDesc(ErrGRPCRootUserNotExist):     ErrGRPCRootUserNotExist,
 		grpc.ErrorDesc(ErrGRPCRootRoleNotExist):     ErrGRPCRootRoleNotExist,
 		grpc.ErrorDesc(ErrGRPCUserAlreadyExist):     ErrGRPCUserAlreadyExist,
+		grpc.ErrorDesc(ErrGRPCUserEmpty):            ErrGRPCUserEmpty,
 		grpc.ErrorDesc(ErrGRPCUserNotFound):         ErrGRPCUserNotFound,
 		grpc.ErrorDesc(ErrGRPCRoleAlreadyExist):     ErrGRPCRoleAlreadyExist,
 		grpc.ErrorDesc(ErrGRPCRoleNotFound):         ErrGRPCRoleNotFound,
@@ -119,6 +121,7 @@ var (
 	ErrRootUserNotExist     = Error(ErrGRPCRootUserNotExist)
 	ErrRootRoleNotExist     = Error(ErrGRPCRootRoleNotExist)
 	ErrUserAlreadyExist     = Error(ErrGRPCUserAlreadyExist)
+	ErrUserEmpty            = Error(ErrGRPCUserEmpty)
 	ErrUserNotFound         = Error(ErrGRPCUserNotFound)
 	ErrRoleAlreadyExist     = Error(ErrGRPCRoleAlreadyExist)
 	ErrRoleNotFound         = Error(ErrGRPCRoleNotFound)

etcdserver/api/v3rpc/util.go

@@ -71,6 +71,8 @@ func togRPCError(err error) error {
 		return rpctypes.ErrGRPCRootRoleNotExist
 	case auth.ErrUserAlreadyExist:
 		return rpctypes.ErrGRPCUserAlreadyExist
+	case auth.ErrUserEmpty:
+		return rpctypes.ErrGRPCUserEmpty
 	case auth.ErrUserNotFound:
 		return rpctypes.ErrGRPCUserNotFound
 	case auth.ErrRoleAlreadyExist: