fix(auth): harden authorization and username validation (#5890)

server/auth/authenticator.go

@@ -141,7 +141,14 @@ func (a *Authenticator) AuthenticateToUser(ctx context.Context, authHeader, cook
 			if !strings.HasPrefix(token, PersonalAccessTokenPrefix) {
 				claims, err := a.AuthenticateByAccessTokenV2(token)
 				if err == nil && claims != nil {
-					return a.store.GetUser(ctx, &store.FindUser{ID: &claims.UserID})
+					user, err := a.store.GetUser(ctx, &store.FindUser{ID: &claims.UserID})
+					if err != nil {
+						return nil, err
+					}
+					if user == nil || user.RowStatus == store.Archived {
+						return nil, nil
+					}
+					return user, nil
 				}
 			} else {
 				user, _, err := a.AuthenticateByPAT(ctx, token)
@@ -174,6 +181,10 @@ func (a *Authenticator) Authenticate(ctx context.Context, authHeader string) *Au
 	if token != "" && !strings.HasPrefix(token, PersonalAccessTokenPrefix) {
 		claims, err := a.AuthenticateByAccessTokenV2(token)
 		if err == nil && claims != nil {
+			user, err := a.store.GetUser(ctx, &store.FindUser{ID: &claims.UserID})
+			if err != nil || user == nil || user.RowStatus == store.Archived {
+				return nil
+			}
 			return &AuthResult{
 				Claims:      claims,
 				AccessToken: token,

server/router/api/v1/attachment_service.go

@@ -140,6 +140,24 @@ func (s *APIV1Service) CreateAttachment(ctx context.Context, request *v1pb.Creat
 	create.Size = int64(size)
 	create.Blob = request.Attachment.Content
 
+	if request.Attachment.Memo != nil {
+		memoUID, err := ExtractMemoUIDFromName(*request.Attachment.Memo)
+		if err != nil {
+			return nil, status.Errorf(codes.InvalidArgument, "invalid memo name: %v", err)
+		}
+		memo, err := s.Store.GetMemo(ctx, &store.FindMemo{UID: &memoUID})
+		if err != nil {
+			return nil, status.Errorf(codes.Internal, "failed to find memo: %v", err)
+		}
+		if memo == nil {
+			return nil, status.Errorf(codes.NotFound, "memo not found: %s", *request.Attachment.Memo)
+		}
+		if !canModifyMemo(user, memo) {
+			return nil, status.Errorf(codes.PermissionDenied, "permission denied")
+		}
+		create.MemoID = &memo.ID
+	}
+
 	if create.Payload == nil || create.Payload.MotionMedia == nil {
 		if detectedMotion := detectAndroidMotionMedia(create.Blob, create.Type, attachmentUID); detectedMotion != nil {
 			create.Payload = ensureAttachmentPayload(create.Payload)
@@ -172,20 +190,6 @@ func (s *APIV1Service) CreateAttachment(ctx context.Context, request *v1pb.Creat
 		return nil, status.Errorf(codes.Internal, "failed to save attachment blob: %v", err)
 	}
 
-	if request.Attachment.Memo != nil {
-		memoUID, err := ExtractMemoUIDFromName(*request.Attachment.Memo)
-		if err != nil {
-			return nil, status.Errorf(codes.InvalidArgument, "invalid memo name: %v", err)
-		}
-		memo, err := s.Store.GetMemo(ctx, &store.FindMemo{UID: &memoUID})
-		if err != nil {
-			return nil, status.Errorf(codes.Internal, "failed to find memo: %v", err)
-		}
-		if memo == nil {
-			return nil, status.Errorf(codes.NotFound, "memo not found: %s", *request.Attachment.Memo)
-		}
-		create.MemoID = &memo.ID
-	}
 	attachment, err := s.Store.CreateAttachment(ctx, create)
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, "failed to create attachment: %v", err)

server/router/api/v1/auth_service.go

@@ -595,6 +595,9 @@ func (s *APIV1Service) fetchCurrentUser(ctx context.Context) (*store.User, error
 	if user == nil {
 		return nil, errors.Errorf("user %d not found", userID)
 	}
+	if user.RowStatus == store.Archived {
+		return nil, nil
+	}
 	return user, nil
 }
 

server/router/api/v1/common.go

@@ -77,3 +77,7 @@ func unmarshalPageToken(s string, pageToken *v1pb.PageToken) error {
 func isSuperUser(user *store.User) bool {
 	return user.Role == store.RoleAdmin
 }
+
+func canModifyMemo(user *store.User, memo *store.Memo) bool {
+	return user != nil && memo != nil && (memo.CreatorID == user.ID || isSuperUser(user))
+}

server/router/api/v1/connect_interceptors_test.go

@@ -2,11 +2,16 @@ package v1
 
 import (
 	"context"
+	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"connectrpc.com/connect"
+	"github.com/labstack/echo/v5"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/protobuf/types/known/emptypb"
+
+	"github.com/usememos/memos/internal/profile"
 )
 
 func TestMetadataInterceptorForwardsSecurityHeaders(t *testing.T) {
@@ -37,3 +42,24 @@ func TestMetadataInterceptorForwardsSecurityHeaders(t *testing.T) {
 		t.Fatalf("metadata interceptor returned error: %v", err)
 	}
 }
+
+func TestAllowedConnectOrigin(t *testing.T) {
+	service := &APIV1Service{
+		Profile: &profile.Profile{InstanceURL: "https://memos.example"},
+	}
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodOptions, "http://localhost/memos.api.v1.AuthService/SignIn", nil)
+	req.Host = "localhost"
+	rec := httptest.NewRecorder()
+	ctx := e.NewContext(req, rec)
+
+	if !service.isAllowedConnectOrigin(ctx, "http://localhost") {
+		t.Fatal("expected same host origin to be allowed")
+	}
+	if !service.isAllowedConnectOrigin(ctx, "https://memos.example") {
+		t.Fatal("expected instance URL origin to be allowed")
+	}
+	if service.isAllowedConnectOrigin(ctx, "https://evil.example") {
+		t.Fatal("expected unknown origin to be denied")
+	}
+}

server/router/api/v1/memo_attachment_service.go

@@ -32,7 +32,7 @@ func (s *APIV1Service) SetMemoAttachments(ctx context.Context, request *v1pb.Set
 	if memo == nil {
 		return nil, status.Errorf(codes.NotFound, "memo not found")
 	}
-	if memo.CreatorID != user.ID && !isSuperUser(user) {
+	if !canModifyMemo(user, memo) {
 		return nil, status.Errorf(codes.PermissionDenied, "permission denied")
 	}
 	if err := s.setMemoAttachmentsInternal(ctx, memo, request.Attachments); err != nil {

server/router/api/v1/sso_username.go

@@ -13,7 +13,7 @@ import (
 // retry loops around concurrent first-time logins.
 func deriveSSOUsername() (string, error) {
 	username := util.GenUUID()
-	if err := validateUsername(username); err != nil {
+	if err := validateWritableUsername(username); err != nil {
 		return "", errors.Wrap(err, "generated UUID did not satisfy username constraints")
 	}
 	return username, nil

server/router/api/v1/test/attachment_service_test.go

@@ -138,6 +138,123 @@ func TestCreateAttachment(t *testing.T) {
 	})
 }
 
+func TestCreateAttachmentMemoPermission(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("owner can create attachment directly linked to memo", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		owner, err := ts.CreateRegularUser(ctx, "attachment-owner")
+		require.NoError(t, err)
+		ownerCtx := ts.CreateUserContext(ctx, owner.ID)
+
+		memo, err := ts.Service.CreateMemo(ownerCtx, &v1pb.CreateMemoRequest{
+			Memo: &v1pb.Memo{
+				Content: "memo with direct attachment",
+			},
+		})
+		require.NoError(t, err)
+
+		attachment, err := ts.Service.CreateAttachment(ownerCtx, &v1pb.CreateAttachmentRequest{
+			Attachment: &v1pb.Attachment{
+				Filename: "owner.txt",
+				Type:     "text/plain",
+				Content:  []byte("owner"),
+				Memo:     &memo.Name,
+			},
+		})
+		require.NoError(t, err)
+		attachmentUID, err := apiv1.ExtractAttachmentUIDFromName(attachment.Name)
+		require.NoError(t, err)
+		stored, err := ts.Store.GetAttachment(ctx, &store.FindAttachment{UID: &attachmentUID})
+		require.NoError(t, err)
+		require.NotNil(t, stored.MemoID)
+		require.Equal(t, memoIDFromName(ctx, t, ts, memo.Name), *stored.MemoID)
+	})
+
+	t.Run("admin can create attachment directly linked to memo", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		owner, err := ts.CreateRegularUser(ctx, "attachment-admin-owner")
+		require.NoError(t, err)
+		ownerCtx := ts.CreateUserContext(ctx, owner.ID)
+		admin, err := ts.CreateHostUser(ctx, "attachment-admin")
+		require.NoError(t, err)
+		adminCtx := ts.CreateUserContext(ctx, admin.ID)
+
+		memo, err := ts.Service.CreateMemo(ownerCtx, &v1pb.CreateMemoRequest{
+			Memo: &v1pb.Memo{
+				Content: "memo with admin attachment",
+			},
+		})
+		require.NoError(t, err)
+
+		attachment, err := ts.Service.CreateAttachment(adminCtx, &v1pb.CreateAttachmentRequest{
+			Attachment: &v1pb.Attachment{
+				Filename: "admin.txt",
+				Type:     "text/plain",
+				Content:  []byte("admin"),
+				Memo:     &memo.Name,
+			},
+		})
+		require.NoError(t, err)
+		attachmentUID, err := apiv1.ExtractAttachmentUIDFromName(attachment.Name)
+		require.NoError(t, err)
+		stored, err := ts.Store.GetAttachment(ctx, &store.FindAttachment{UID: &attachmentUID})
+		require.NoError(t, err)
+		require.NotNil(t, stored.MemoID)
+		require.Equal(t, memoIDFromName(ctx, t, ts, memo.Name), *stored.MemoID)
+	})
+
+	t.Run("non-owner cannot create attachment directly linked to memo", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		owner, err := ts.CreateRegularUser(ctx, "attachment-owner-denied")
+		require.NoError(t, err)
+		ownerCtx := ts.CreateUserContext(ctx, owner.ID)
+		other, err := ts.CreateRegularUser(ctx, "attachment-other-denied")
+		require.NoError(t, err)
+		otherCtx := ts.CreateUserContext(ctx, other.ID)
+
+		memo, err := ts.Service.CreateMemo(ownerCtx, &v1pb.CreateMemoRequest{
+			Memo: &v1pb.Memo{
+				Content: "memo with blocked attachment",
+			},
+		})
+		require.NoError(t, err)
+
+		_, err = ts.Service.CreateAttachment(otherCtx, &v1pb.CreateAttachmentRequest{
+			Attachment: &v1pb.Attachment{
+				Filename: "blocked.txt",
+				Type:     "text/plain",
+				Content:  []byte("blocked"),
+				Memo:     &memo.Name,
+			},
+		})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "permission denied")
+
+		attachments, err := ts.Store.ListAttachments(ctx, &store.FindAttachment{
+			CreatorID: &other.ID,
+		})
+		require.NoError(t, err)
+		require.Empty(t, attachments)
+	})
+}
+
+func memoIDFromName(ctx context.Context, t *testing.T, ts *TestService, name string) int32 {
+	t.Helper()
+	memoUID, err := apiv1.ExtractMemoUIDFromName(name)
+	require.NoError(t, err)
+	memo, err := ts.Store.GetMemo(ctx, &store.FindMemo{UID: &memoUID})
+	require.NoError(t, err)
+	require.NotNil(t, memo)
+	return memo.ID
+}
+
 func TestCreateAttachmentMotionMedia(t *testing.T) {
 	ts := NewTestService(t)
 	defer ts.Cleanup()

server/router/api/v1/test/auth_service_test.go

@@ -154,6 +154,23 @@ func TestListAndDeleteLinkedIdentities(t *testing.T) {
 	require.Empty(t, listResp.LinkedIdentities)
 }
 
+func TestListLinkedIdentitiesRequiresAuthentication(t *testing.T) {
+	t.Parallel()
+
+	ts := NewTestService(t)
+	defer ts.Cleanup()
+
+	ctx := context.Background()
+	user, err := ts.CreateRegularUser(ctx, "linked-identity-auth")
+	require.NoError(t, err)
+
+	_, err = ts.Service.ListLinkedIdentities(ctx, &v1pb.ListLinkedIdentitiesRequest{
+		Parent: apiv1.BuildUserName(user.Username),
+	})
+	require.Error(t, err)
+	require.Equal(t, codes.Unauthenticated, status.Code(err))
+}
+
 func TestCreateLinkedIdentityRejectsSecondIdentityForSameProvider(t *testing.T) {
 	t.Parallel()
 

server/router/api/v1/test/auth_test.go

@@ -78,6 +78,33 @@ func TestAuthenticatorAccessTokenV2(t *testing.T) {
 		_, err = authenticator.AuthenticateByAccessTokenV2(token)
 		assert.Error(t, err)
 	})
+
+	t.Run("request authentication rejects archived user", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "archived-access-token")
+		require.NoError(t, err)
+		token, _, err := auth.GenerateAccessTokenV2(
+			user.ID,
+			user.Username,
+			string(user.Role),
+			string(user.RowStatus),
+			[]byte(ts.Secret),
+		)
+		require.NoError(t, err)
+
+		archivedStatus := store.Archived
+		_, err = ts.Store.UpdateUser(ctx, &store.UpdateUser{
+			ID:        user.ID,
+			RowStatus: &archivedStatus,
+		})
+		require.NoError(t, err)
+
+		authenticator := auth.NewAuthenticator(ts.Store, ts.Secret)
+		result := authenticator.Authenticate(ctx, "Bearer "+token)
+		assert.Nil(t, result)
+	})
 }
 
 func TestAuthenticatorRefreshToken(t *testing.T) {

server/router/api/v1/test/user_search_test.go

@@ -52,3 +52,20 @@ func TestBatchGetUsersRejectsTooManyUsernames(t *testing.T) {
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "too many usernames")
 }
+
+func TestBatchGetUsersRejectsTooManyNonEmptyUsernamesBeforeDedupe(t *testing.T) {
+	ctx := context.Background()
+	ts := NewTestService(t)
+	defer ts.Cleanup()
+
+	usernames := make([]string, 0, 101)
+	for range 101 {
+		usernames = append(usernames, "legacy@example.com")
+	}
+
+	_, err := ts.Service.BatchGetUsers(ctx, &apiv1.BatchGetUsersRequest{
+		Usernames: usernames,
+	})
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "too many usernames")
+}

server/router/api/v1/test/user_service_email_username_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	"golang.org/x/crypto/bcrypt"
 	"google.golang.org/protobuf/types/known/fieldmaskpb"
 
 	apiv1 "github.com/usememos/memos/proto/gen/api/v1"
@@ -15,6 +16,26 @@ import (
 func TestUserServiceWithEmailLikeUsername(t *testing.T) {
 	ctx := context.Background()
 
+	t.Run("SignIn accepts email-like legacy username", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user := createLegacyPasswordUser(ctx, t, ts, "signin@example.com", "password123")
+
+		signInCtx := apiv1server.WithHeaderCarrier(ctx)
+		resp, err := ts.Service.SignIn(signInCtx, &apiv1.SignInRequest{
+			Credentials: &apiv1.SignInRequest_PasswordCredentials_{
+				PasswordCredentials: &apiv1.SignInRequest_PasswordCredentials{
+					Username: user.Username,
+					Password: "password123",
+				},
+			},
+		})
+		require.NoError(t, err)
+		require.Equal(t, user.Username, resp.User.Username)
+		require.NotEmpty(t, resp.AccessToken)
+	})
+
 	t.Run("GetUser accepts email-like username in resource name", func(t *testing.T) {
 		ts := NewTestService(t)
 		defer ts.Cleanup()
@@ -31,6 +52,38 @@ func TestUserServiceWithEmailLikeUsername(t *testing.T) {
 		require.Equal(t, "users/alice@example.com", got.Name)
 	})
 
+	t.Run("BatchGetUsers accepts email-like legacy username", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "batch@example.com")
+		require.NoError(t, err)
+
+		resp, err := ts.Service.BatchGetUsers(ctx, &apiv1.BatchGetUsersRequest{
+			Usernames: []string{" batch@example.com ", "missing@example.com", "batch@example.com"},
+		})
+		require.NoError(t, err)
+		require.Len(t, resp.Users, 1)
+		require.Equal(t, user.Username, resp.Users[0].Username)
+		require.Equal(t, "users/batch@example.com", resp.Users[0].Name)
+	})
+
+	t.Run("BatchGetUsers accepts underscore legacy username", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "legacy_batch")
+		require.NoError(t, err)
+
+		resp, err := ts.Service.BatchGetUsers(ctx, &apiv1.BatchGetUsersRequest{
+			Usernames: []string{"legacy_batch"},
+		})
+		require.NoError(t, err)
+		require.Len(t, resp.Users, 1)
+		require.Equal(t, user.Username, resp.Users[0].Username)
+		require.Equal(t, "users/legacy_batch", resp.Users[0].Name)
+	})
+
 	t.Run("ListUserSettings accepts email-like username in parent", func(t *testing.T) {
 		ts := NewTestService(t)
 		defer ts.Cleanup()
@@ -92,14 +145,70 @@ func TestUserServiceWithEmailLikeUsername(t *testing.T) {
 		require.Equal(t, "bob", stored.Username)
 	})
 
+	t.Run("UpdateUser rejects writing invalid username values", func(t *testing.T) {
+		for _, username := range []string{"alice@example.com", "legacy_user"} {
+			t.Run(username, func(t *testing.T) {
+				ts := NewTestService(t)
+				defer ts.Cleanup()
+
+				user, err := ts.CreateRegularUser(ctx, "rename@example.com")
+				require.NoError(t, err)
+
+				authCtx := ts.CreateUserContext(ctx, user.ID)
+				_, err = ts.Service.UpdateUser(authCtx, &apiv1.UpdateUserRequest{
+					User: &apiv1.User{
+						Name:     "users/rename@example.com",
+						Username: username,
+					},
+					UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"username"}},
+				})
+				require.Error(t, err)
+				require.Contains(t, err.Error(), "invalid username")
+
+				stored, err := ts.Store.GetUser(ctx, &store.FindUser{ID: &user.ID})
+				require.NoError(t, err)
+				require.NotNil(t, stored)
+				require.Equal(t, "rename@example.com", stored.Username)
+			})
+		}
+	})
+
+	t.Run("admin cannot rename user to invalid username", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "admin-rename-target")
+		require.NoError(t, err)
+		admin, err := ts.CreateHostUser(ctx, "rename-admin")
+		require.NoError(t, err)
+
+		adminCtx := ts.CreateUserContext(ctx, admin.ID)
+		_, err = ts.Service.UpdateUser(adminCtx, &apiv1.UpdateUserRequest{
+			User: &apiv1.User{
+				Name:     apiv1server.BuildUserName(user.Username),
+				Username: "admin@example.com",
+			},
+			UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"username"}},
+		})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "invalid username")
+
+		stored, err := ts.Store.GetUser(ctx, &store.FindUser{ID: &user.ID})
+		require.NoError(t, err)
+		require.NotNil(t, stored)
+		require.Equal(t, "admin-rename-target", stored.Username)
+	})
+
 	t.Run("UpdateUser can archive email-like username account", func(t *testing.T) {
 		ts := NewTestService(t)
 		defer ts.Cleanup()
 
 		user, err := ts.CreateRegularUser(ctx, "dave@example.com")
 		require.NoError(t, err)
+		admin, err := ts.CreateHostUser(ctx, "email-admin")
+		require.NoError(t, err)
 
-		authCtx := ts.CreateUserContext(ctx, user.ID)
+		authCtx := ts.CreateUserContext(ctx, admin.ID)
 		updated, err := ts.Service.UpdateUser(authCtx, &apiv1.UpdateUserRequest{
 			User: &apiv1.User{
 				Name:  "users/dave@example.com",
@@ -134,3 +243,17 @@ func TestUserServiceWithEmailLikeUsername(t *testing.T) {
 		require.Nil(t, deleted)
 	})
 }
+
+func createLegacyPasswordUser(ctx context.Context, t *testing.T, ts *TestService, username, password string) *store.User {
+	passwordHash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	require.NoError(t, err)
+
+	user, err := ts.Store.CreateUser(ctx, &store.User{
+		Username:     username,
+		Role:         store.RoleUser,
+		Email:        username,
+		PasswordHash: string(passwordHash),
+	})
+	require.NoError(t, err)
+	return user
+}

server/router/api/v1/test/user_service_registration_test.go

@@ -2,6 +2,8 @@ package test
 
 import (
 	"context"
+	"fmt"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -10,6 +12,7 @@ import (
 	apiv1 "github.com/usememos/memos/proto/gen/api/v1"
 	storepb "github.com/usememos/memos/proto/gen/store"
 	apiv1server "github.com/usememos/memos/server/router/api/v1"
+	"github.com/usememos/memos/store"
 )
 
 func TestCreateUserRegistration(t *testing.T) {
@@ -218,6 +221,41 @@ func TestCreateUserRegistration(t *testing.T) {
 		require.Contains(t, err.Error(), "password must not be empty")
 	})
 
+	t.Run("CreateUser rejects invalid writable usernames", func(t *testing.T) {
+		for _, username := range []string{"alice@example.com", "legacy_user", "123"} {
+			t.Run(username, func(t *testing.T) {
+				ts := NewTestService(t)
+				defer ts.Cleanup()
+
+				_, err := ts.Service.CreateUser(ctx, &apiv1.CreateUserRequest{
+					User: &apiv1.User{
+						Username: username,
+						Email:    "newuser@example.com",
+						Password: "password123",
+					},
+				})
+				require.Error(t, err)
+				require.Contains(t, err.Error(), "invalid username")
+			})
+		}
+	})
+
+	t.Run("CreateUser validate only rejects invalid writable username", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		_, err := ts.Service.CreateUser(ctx, &apiv1.CreateUserRequest{
+			User: &apiv1.User{
+				Username: "alice@example.com",
+				Email:    "newuser@example.com",
+				Password: "password123",
+			},
+			ValidateOnly: true,
+		})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "invalid username")
+	})
+
 	t.Run("UpdateUser rejects empty password", func(t *testing.T) {
 		ts := NewTestService(t)
 		defer ts.Cleanup()
@@ -236,4 +274,114 @@ func TestCreateUserRegistration(t *testing.T) {
 		require.Error(t, err)
 		require.Contains(t, err.Error(), "password must not be empty")
 	})
+
+	t.Run("UpdateUser rejects missing user message", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "missing-message")
+		require.NoError(t, err)
+
+		authCtx := ts.CreateUserContext(ctx, user.ID)
+		_, err = ts.Service.UpdateUser(authCtx, &apiv1.UpdateUserRequest{
+			UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"display_name"}},
+		})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "user is required")
+	})
+
+	t.Run("CreateUser concurrent first setup creates one admin", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		const workers = 12
+		var wg sync.WaitGroup
+		for i := range workers {
+			wg.Go(func() {
+				_, _ = ts.Service.CreateUser(ctx, &apiv1.CreateUserRequest{
+					User: &apiv1.User{
+						Username: fmt.Sprintf("setup-user-%d", i),
+						Email:    "setup-user@example.com",
+						Password: "password123",
+					},
+				})
+			})
+		}
+		wg.Wait()
+
+		users, err := ts.Store.ListUsers(ctx, &store.FindUser{})
+		require.NoError(t, err)
+		adminCount := 0
+		for _, user := range users {
+			if user.Role == store.RoleAdmin {
+				adminCount++
+			}
+		}
+		require.Equal(t, 1, adminCount)
+	})
+
+	t.Run("UpdateUser state requires admin", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "state-user")
+		require.NoError(t, err)
+		userCtx := ts.CreateUserContext(ctx, user.ID)
+		_, err = ts.Service.UpdateUser(userCtx, &apiv1.UpdateUserRequest{
+			User: &apiv1.User{
+				Name:  apiv1server.BuildUserName(user.Username),
+				State: apiv1.State_ARCHIVED,
+			},
+			UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"state"}},
+		})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "permission denied")
+
+		admin, err := ts.CreateHostUser(ctx, "state-admin")
+		require.NoError(t, err)
+		adminCtx := ts.CreateUserContext(ctx, admin.ID)
+		updated, err := ts.Service.UpdateUser(adminCtx, &apiv1.UpdateUserRequest{
+			User: &apiv1.User{
+				Name:  apiv1server.BuildUserName(user.Username),
+				State: apiv1.State_ARCHIVED,
+			},
+			UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"state"}},
+		})
+		require.NoError(t, err)
+		require.Equal(t, apiv1.State_ARCHIVED, updated.State)
+	})
+
+	t.Run("archived user context is rejected", func(t *testing.T) {
+		ts := NewTestService(t)
+		defer ts.Cleanup()
+
+		user, err := ts.CreateRegularUser(ctx, "archived-access-user")
+		require.NoError(t, err)
+		userCtx := ts.CreateUserContext(ctx, user.ID)
+		archived := store.Archived
+		_, err = ts.Store.UpdateUser(ctx, &store.UpdateUser{
+			ID:        user.ID,
+			RowStatus: &archived,
+		})
+		require.NoError(t, err)
+
+		_, err = ts.Service.GetCurrentUser(userCtx, &apiv1.GetCurrentUserRequest{})
+		require.Error(t, err)
+
+		_, err = ts.Service.CreateMemo(userCtx, &apiv1.CreateMemoRequest{
+			Memo: &apiv1.Memo{
+				Content: "should not be created",
+			},
+		})
+		require.Error(t, err)
+
+		_, err = ts.Service.UpdateUser(userCtx, &apiv1.UpdateUserRequest{
+			User: &apiv1.User{
+				Name:  apiv1server.BuildUserName(user.Username),
+				State: apiv1.State_NORMAL,
+			},
+			UpdateMask: &fieldmaskpb.FieldMask{Paths: []string{"state"}},
+		})
+		require.Error(t, err)
+	})
 }

server/router/api/v1/user_resource_name.go

@@ -26,7 +26,7 @@ func parseUsernameFromName(name string) (string, error) {
 	return username, nil
 }
 
-func validateUsername(username string) error {
+func validateWritableUsername(username string) error {
 	if username == "" || isNumericUsername(username) || !base.UIDMatcher.MatchString(username) {
 		return errors.Errorf("invalid username %q", username)
 	}

server/router/api/v1/user_resource_name_test.go

+package v1
+
+import (
+	"testing"
+)
+
+func TestValidateWritableUsername(t *testing.T) {
+	tests := []struct {
+		name      string
+		username  string
+		wantError bool
+	}{
+		{
+			name:     "lowercase",
+			username: "alice",
+		},
+		{
+			name:     "mixed case",
+			username: "Alice",
+		},
+		{
+			name:     "hyphenated",
+			username: "alice-smith",
+		},
+		{
+			name:     "uuid",
+			username: "550e8400-e29b-41d4-a716-446655440000",
+		},
+		{
+			name:      "empty",
+			username:  "",
+			wantError: true,
+		},
+		{
+			name:      "numeric",
+			username:  "123",
+			wantError: true,
+		},
+		{
+			name:      "email",
+			username:  "alice@example.com",
+			wantError: true,
+		},
+		{
+			name:      "underscore",
+			username:  "alice_smith",
+			wantError: true,
+		},
+		{
+			name:      "space",
+			username:  "alice smith",
+			wantError: true,
+		},
+		{
+			name:      "slash",
+			username:  "alice/smith",
+			wantError: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			err := validateWritableUsername(test.username)
+			if test.wantError && err == nil {
+				t.Fatalf("validateWritableUsername(%q) succeeded, want error", test.username)
+			}
+			if !test.wantError && err != nil {
+				t.Fatalf("validateWritableUsername(%q) returned error: %v", test.username, err)
+			}
+		})
+	}
+}
+
+func TestParseUsernameFromNameAllowsLegacyUsernames(t *testing.T) {
+	tests := []struct {
+		name     string
+		want     string
+		wantFail bool
+	}{
+		{
+			name: "users/alice",
+			want: "alice",
+		},
+		{
+			name: "users/alice@example.com",
+			want: "alice@example.com",
+		},
+		{
+			name: "users/alice_smith",
+			want: "alice_smith",
+		},
+		{
+			name:     "users/",
+			wantFail: true,
+		},
+		{
+			name:     "invalid/alice",
+			wantFail: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := parseUsernameFromName(test.name)
+			if test.wantFail && err == nil {
+				t.Fatalf("parseUsernameFromName(%q) succeeded, want error", test.name)
+			}
+			if !test.wantFail && err != nil {
+				t.Fatalf("parseUsernameFromName(%q) returned error: %v", test.name, err)
+			}
+			if got != test.want {
+				t.Fatalf("parseUsernameFromName(%q) = %q, want %q", test.name, got, test.want)
+			}
+		})
+	}
+}

server/router/api/v1/v1.go

@@ -3,6 +3,8 @@ package v1
 import (
 	"context"
 	"net/http"
+	"net/url"
+	"strings"
 
 	"connectrpc.com/connect"
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
@@ -143,8 +145,11 @@ func (s *APIV1Service) RegisterGateway(ctx context.Context, echoServer *echo.Ech
 
 	// Wrap with CORS for browser access
 	corsHandler := middleware.CORSWithConfig(middleware.CORSConfig{
-		UnsafeAllowOriginFunc: func(_ *echo.Context, origin string) (string, bool, error) {
-			return origin, true, nil
+		UnsafeAllowOriginFunc: func(c *echo.Context, origin string) (string, bool, error) {
+			if s.isAllowedConnectOrigin(c, origin) {
+				return origin, true, nil
+			}
+			return "", false, nil
 		},
 		AllowMethods:     []string{http.MethodGet, http.MethodPost, http.MethodOptions},
 		AllowHeaders:     []string{"*"},
@@ -155,3 +160,23 @@ func (s *APIV1Service) RegisterGateway(ctx context.Context, echoServer *echo.Ech
 
 	return nil
 }
+
+func (s *APIV1Service) isAllowedConnectOrigin(c *echo.Context, origin string) bool {
+	originURL, err := url.Parse(origin)
+	if err != nil || originURL.Scheme == "" || originURL.Host == "" {
+		return false
+	}
+
+	if strings.EqualFold(originURL.Host, c.Request().Host) {
+		return true
+	}
+
+	if s.Profile == nil || s.Profile.InstanceURL == "" {
+		return false
+	}
+	instanceURL, err := url.Parse(s.Profile.InstanceURL)
+	if err != nil || instanceURL.Scheme == "" || instanceURL.Host == "" {
+		return false
+	}
+	return strings.EqualFold(originURL.Scheme, instanceURL.Scheme) && strings.EqualFold(originURL.Host, instanceURL.Host)
+}

store/store.go

 package store
 
 import (
+	"sync"
 	"time"
 
 	"github.com/usememos/memos/internal/profile"
@@ -12,6 +13,8 @@ type Store struct {
 	profile *profile.Profile
 	driver  Driver
 
+	userCreateMu sync.Mutex
+
 	// Cache settings
 	cacheConfig cache.Config
 

store/user.go

@@ -95,6 +95,30 @@ func (s *Store) CreateUser(ctx context.Context, create *User) (*User, error) {
 	return user, nil
 }
 
+// CreateUserIfNoUsers creates a user only when the instance has no users.
+// The in-process lock prevents concurrent first-user setup requests from
+// creating multiple admins in the same server process.
+func (s *Store) CreateUserIfNoUsers(ctx context.Context, create *User) (*User, bool, error) {
+	s.userCreateMu.Lock()
+	defer s.userCreateMu.Unlock()
+
+	limitOne := 1
+	users, err := s.driver.ListUsers(ctx, &FindUser{Limit: &limitOne})
+	if err != nil {
+		return nil, false, err
+	}
+	if len(users) > 0 {
+		return nil, false, nil
+	}
+
+	user, err := s.driver.CreateUser(ctx, create)
+	if err != nil {
+		return nil, false, err
+	}
+	s.userCache.Set(ctx, userCacheKey(user.ID), user)
+	return user, true, nil
+}
+
 func (s *Store) UpdateUser(ctx context.Context, update *UpdateUser) (*User, error) {
 	user, err := s.driver.UpdateUser(ctx, update)
 	if err != nil {