fix: enforce expiry for web password resets

internal/server/handlers_auth.go

@@ -193,24 +193,18 @@ func (s *Server) handleReset(w http.ResponseWriter, r *http.Request) {
 		jsonErr(w, 400, err)
 		return
 	}
-	var userID, expiresAt string
-	err := s.db.QueryRow("SELECT user_id, expires_at FROM server_email_tokens WHERE token=? AND purpose='reset'",
-		req.Token).Scan(&userID, &expiresAt)
-	if err != nil {
+	_, err := s.resetPasswordWithToken(req.Token, req.NewPassword)
+	if err == errResetTokenInvalid {
 		jsonErr(w, 400, "invalid or expired token")
 		return
 	}
-	exp, err := time.Parse(time.RFC3339, expiresAt)
-	if err != nil || time.Now().After(exp) {
+	if err == errResetTokenExpired {
 		jsonErr(w, 400, "token expired")
 		return
 	}
-	hash, err := bcrypt.GenerateFromPassword([]byte(req.NewPassword), bcrypt.DefaultCost)
 	if err != nil {
 		jsonErr(w, 500, "internal error")
 		return
 	}
-	s.db.Exec("UPDATE server_users SET password_hash=? WHERE id=?", string(hash), userID)
-	s.db.Exec("DELETE FROM server_email_tokens WHERE token=?", req.Token)
 	jsonOK(w, map[string]string{"status": "password reset"})
 }

internal/server/handlers_web_user.go

@@ -212,15 +212,17 @@ func (s *Server) handleUserWebReset(w http.ResponseWriter, r *http.Request) {
 			w.Write([]byte(errorPageHTML(locale, t(locale, "common.error"), t(locale, "server.passwordsDoNotMatch"), "/reset?token="+token)))
 			return
 		}
-		var userID string
-		err := s.db.QueryRow("SELECT user_id FROM server_email_tokens WHERE token=? AND purpose='reset'", token).Scan(&userID)
-		if err != nil {
+		userID, err := s.resetPasswordWithToken(token, newPass)
+		if err == errResetTokenInvalid || err == errResetTokenExpired {
 			http.Redirect(w, r, "/forgot", http.StatusFound)
 			return
 		}
-		hash, _ := bcrypt.GenerateFromPassword([]byte(newPass), bcrypt.DefaultCost)
-		s.db.Exec("UPDATE server_users SET password_hash=? WHERE id=?", string(hash), userID)
-		s.db.Exec("DELETE FROM server_email_tokens WHERE token=?", token)
+		if err != nil {
+			w.Header().Set("Content-Type", "text/html; charset=utf-8")
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(errorPageHTML(locale, t(locale, "common.error"), t(locale, "common.error"), "/forgot")))
+			return
+		}
 		log.Printf("reset: user %s reset password", userID)
 		w.Header().Set("Content-Type", "text/html; charset=utf-8")
 		w.Write([]byte(resetDoneHTML(locale)))

internal/server/password_reset.go

@@ -0,0 +1,69 @@
+package server
+
+import (
+	"database/sql"
+	"errors"
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+var (
+	errResetTokenInvalid = errors.New("invalid reset token")
+	errResetTokenExpired = errors.New("expired reset token")
+)
+
+func (s *Server) resetPasswordWithToken(token, newPassword string) (string, error) {
+	tx, err := s.db.Begin()
+	if err != nil {
+		return "", err
+	}
+	defer tx.Rollback()
+
+	var userID, expiresAt string
+	err = tx.QueryRow(`SELECT user_id, expires_at FROM server_email_tokens
+		WHERE token=? AND purpose='reset'`, token).Scan(&userID, &expiresAt)
+	if errors.Is(err, sql.ErrNoRows) {
+		return "", errResetTokenInvalid
+	}
+	if err != nil {
+		return "", err
+	}
+	expiresAtTime, err := time.Parse(time.RFC3339, expiresAt)
+	if err != nil || !time.Now().Before(expiresAtTime) {
+		return "", errResetTokenExpired
+	}
+
+	deleted, err := tx.Exec(`DELETE FROM server_email_tokens
+		WHERE token=? AND purpose='reset' AND expires_at=?`, token, expiresAt)
+	if err != nil {
+		return "", err
+	}
+	deletedCount, err := deleted.RowsAffected()
+	if err != nil {
+		return "", err
+	}
+	if deletedCount != 1 {
+		return "", errResetTokenInvalid
+	}
+
+	hash, err := bcrypt.GenerateFromPassword([]byte(newPassword), bcrypt.DefaultCost)
+	if err != nil {
+		return "", err
+	}
+	updated, err := tx.Exec("UPDATE server_users SET password_hash=? WHERE id=?", string(hash), userID)
+	if err != nil {
+		return "", err
+	}
+	updatedCount, err := updated.RowsAffected()
+	if err != nil {
+		return "", err
+	}
+	if updatedCount != 1 {
+		return "", errResetTokenInvalid
+	}
+	if err := tx.Commit(); err != nil {
+		return "", err
+	}
+	return userID, nil
+}

internal/server/server_test.go

@@ -6,8 +6,10 @@ import (
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
@@ -343,6 +345,33 @@ func TestDeviceRegisterRequiresValidVaultID(t *testing.T) {
 	}
 }
 
+func TestWebResetRejectsExpiredToken(t *testing.T) {
+	s, _ := newSyncHTTPServer(t)
+	defer s.Close()
+
+	oldPassword := "correct horse battery staple"
+	insertPairableUser(t, s, "user-a", "alice", oldPassword)
+	now := time.Now().UTC().Format(time.RFC3339)
+	if _, err := s.db.Exec(`INSERT INTO server_email_tokens
+		(token, user_id, purpose, expires_at, created_at)
+		VALUES (?, ?, 'reset', ?, ?)`, "expired-reset-token", "user-a", time.Now().Add(-time.Hour).UTC().Format(time.RFC3339), now); err != nil {
+		t.Fatalf("insert reset token: %v", err)
+	}
+
+	response := postWebReset(t, s, "expired-reset-token", "new secret password")
+	if response.Code != http.StatusFound || response.Header().Get("Location") != "/forgot" {
+		t.Fatalf("expired reset response status=%d location=%q, want 302 /forgot", response.Code, response.Header().Get("Location"))
+	}
+
+	var passwordHash string
+	if err := s.db.QueryRow("SELECT password_hash FROM server_users WHERE id=?", "user-a").Scan(&passwordHash); err != nil {
+		t.Fatalf("read password hash: %v", err)
+	}
+	if bcrypt.CompareHashAndPassword([]byte(passwordHash), []byte(oldPassword)) != nil {
+		t.Fatal("expired reset changed the password")
+	}
+}
+
 func TestNewServerMigratesLegacyOperationScope(t *testing.T) {
 	dir := t.TempDir()
 	dbPath := filepath.Join(dir, "legacy.db")
@@ -508,6 +537,20 @@ func pairSyncDevice(t *testing.T, serverURL, username, password, vaultID string)
 	}
 }
 
+func postWebReset(t *testing.T, s *Server, token, password string) *httptest.ResponseRecorder {
+	t.Helper()
+	form := url.Values{
+		"token":    {token},
+		"password": {password},
+		"confirm":  {password},
+	}
+	request := httptest.NewRequest(http.MethodPost, "/reset", strings.NewReader(form.Encode()))
+	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	response := httptest.NewRecorder()
+	s.mux.ServeHTTP(response, request)
+	return response
+}
+
 func postJSON(t *testing.T, url, token string, body interface{}) map[string]interface{} {
 	t.Helper()
 	status, out := postJSONStatus(t, url, token, body)