feat: add authenticated password changes

CHANGELOG.md

@@ -10,6 +10,9 @@ All notable changes to EvoScientist WebUI are documented in this file.
   pages and API routes are protected by a signed HTTP-only session cookie, and
   successful logins record their latest timestamp and counter in the local
   EvoScientist data directory.
+- Added an authenticated change-password dialog. It verifies the current
+  password, atomically updates `.env`, rotates the session signing key, and
+  invalidates prior sessions.
 
 ### Fixed
 

README.md

@@ -130,7 +130,9 @@ enabled, incomplete credentials fail closed. Successful logins create an
 HTTP-only signed session cookie and update the most recent login timestamp and
 counter in `~/.evoscientist/webui-auth.json` (or
 `$EVOSCIENTIST_DATA_DIR/webui-auth.json` when that directory is configured).
-Use the sign-out icon in the top bar to end the current session.
+Use the key icon in the top bar to change the password. It requires the current
+password, updates the local `.env`, rotates the session signing key, and signs
+out all other sessions. Use the sign-out icon to end the current session.
 
 <p align="right"><a href="#top">🔝Back to top</a></p>
 

src/app/api/auth/password/route.ts

@@ -0,0 +1,104 @@
+import { type NextRequest, NextResponse } from "next/server";
+import { isAuthenticationEnabled } from "@/lib/auth";
+import {
+  AuthConfigurationError,
+  authCookieOptions,
+  createSession,
+  getAuthConfiguration,
+  recordLogin,
+  updateAuthPassword,
+  verifyCredentials,
+} from "@/lib/server/auth";
+
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
+
+const NO_STORE = { "Cache-Control": "no-store" };
+
+function hasControlCharacter(value: string): boolean {
+  for (let index = 0; index < value.length; index += 1) {
+    const code = value.charCodeAt(index);
+    if (code < 32 || code === 127) return true;
+  }
+  return false;
+}
+
+function passwordError(password: string): string | null {
+  if (password.length < 8) return "New password must contain at least 8 characters.";
+  if (password.length > 256) return "New password is too long.";
+  if (hasControlCharacter(password)) {
+    return "New password contains unsupported control characters.";
+  }
+  return null;
+}
+
+export async function POST(request: NextRequest) {
+  if (!isAuthenticationEnabled()) {
+    return NextResponse.json(
+      { error: "WebUI authentication is disabled." },
+      { status: 404, headers: NO_STORE }
+    );
+  }
+  const origin = request.headers.get("origin");
+  if (origin && origin !== request.nextUrl.origin) {
+    return NextResponse.json(
+      { error: "Cross-origin password changes are not allowed." },
+      { status: 403, headers: NO_STORE }
+    );
+  }
+  const body = (await request.json().catch(() => null)) as {
+    currentPassword?: unknown;
+    newPassword?: unknown;
+    confirmPassword?: unknown;
+  } | null;
+  const currentPassword =
+    typeof body?.currentPassword === "string" ? body.currentPassword : "";
+  const newPassword =
+    typeof body?.newPassword === "string" ? body.newPassword : "";
+  const confirmPassword =
+    typeof body?.confirmPassword === "string" ? body.confirmPassword : "";
+  const validationError = passwordError(newPassword);
+  if (!currentPassword || !newPassword || !confirmPassword || validationError) {
+    return NextResponse.json(
+      { error: validationError ?? "Complete all password fields." },
+      { status: 400, headers: NO_STORE }
+    );
+  }
+  if (newPassword !== confirmPassword) {
+    return NextResponse.json(
+      { error: "New passwords do not match." },
+      { status: 400, headers: NO_STORE }
+    );
+  }
+
+  try {
+    const config = getAuthConfiguration();
+    if (!verifyCredentials(config.username, currentPassword)) {
+      return NextResponse.json(
+        { error: "Current password is incorrect." },
+        { status: 401, headers: NO_STORE }
+      );
+    }
+    if (currentPassword === newPassword) {
+      return NextResponse.json(
+        { error: "Choose a password different from the current one." },
+        { status: 400, headers: NO_STORE }
+      );
+    }
+    await updateAuthPassword(newPassword);
+    const { token, payload } = createSession(config.username);
+    await recordLogin(payload);
+    const response = NextResponse.json({ ok: true }, { headers: NO_STORE });
+    response.cookies.set({ ...authCookieOptions(), value: token });
+    return response;
+  } catch (error) {
+    const message =
+      error instanceof AuthConfigurationError
+        ? error.message
+        : "Unable to change the password.";
+    return NextResponse.json(
+      { error: message },
+      { status: 503, headers: NO_STORE }
+    );
+  }
+}

src/app/components/ChangePasswordDialog.tsx

@@ -0,0 +1,144 @@
+"use client";
+
+import { FormEvent, useEffect, useState } from "react";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+
+interface ChangePasswordDialogProps {
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+}
+
+export function ChangePasswordDialog({
+  open,
+  onOpenChange,
+}: ChangePasswordDialogProps) {
+  const [currentPassword, setCurrentPassword] = useState("");
+  const [newPassword, setNewPassword] = useState("");
+  const [confirmPassword, setConfirmPassword] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [saving, setSaving] = useState(false);
+
+  useEffect(() => {
+    if (!open) {
+      setCurrentPassword("");
+      setNewPassword("");
+      setConfirmPassword("");
+      setError(null);
+      setSaving(false);
+    }
+  }, [open]);
+
+  const submit = async (event: FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+    if (saving) return;
+    setSaving(true);
+    setError(null);
+    try {
+      const response = await fetch("/api/auth/password", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        credentials: "same-origin",
+        body: JSON.stringify({
+          currentPassword,
+          newPassword,
+          confirmPassword,
+        }),
+      });
+      const body = (await response.json().catch(() => ({}))) as {
+        error?: string;
+      };
+      if (!response.ok) {
+        throw new Error(body.error || "Unable to change the password.");
+      }
+      onOpenChange(false);
+    } catch (reason) {
+      setError(
+        reason instanceof Error ? reason.message : "Unable to change the password."
+      );
+      setSaving(false);
+    }
+  };
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="sm:max-w-md">
+        <DialogHeader>
+          <DialogTitle>Change Password</DialogTitle>
+          <DialogDescription>
+            Changing the password signs out every existing session except this
+            one.
+          </DialogDescription>
+        </DialogHeader>
+        <form method="post" onSubmit={submit} className="space-y-4">
+          <div className="space-y-1.5">
+            <Label htmlFor="current-password">Current password</Label>
+            <Input
+              id="current-password"
+              type="password"
+              autoComplete="current-password"
+              value={currentPassword}
+              onChange={(event) => setCurrentPassword(event.target.value)}
+              disabled={saving}
+              required
+              autoFocus
+            />
+          </div>
+          <div className="space-y-1.5">
+            <Label htmlFor="new-password">New password</Label>
+            <Input
+              id="new-password"
+              type="password"
+              autoComplete="new-password"
+              value={newPassword}
+              onChange={(event) => setNewPassword(event.target.value)}
+              disabled={saving}
+              minLength={8}
+              required
+            />
+          </div>
+          <div className="space-y-1.5">
+            <Label htmlFor="confirm-password">Confirm new password</Label>
+            <Input
+              id="confirm-password"
+              type="password"
+              autoComplete="new-password"
+              value={confirmPassword}
+              onChange={(event) => setConfirmPassword(event.target.value)}
+              disabled={saving}
+              minLength={8}
+              required
+            />
+          </div>
+          {error && (
+            <p role="alert" className="text-sm text-destructive">
+              {error}
+            </p>
+          )}
+          <DialogFooter>
+            <Button
+              type="button"
+              variant="outline"
+              onClick={() => onOpenChange(false)}
+              disabled={saving}
+            >
+              Cancel
+            </Button>
+            <Button type="submit" disabled={saving}>
+              {saving ? "Saving..." : "Save Password"}
+            </Button>
+          </DialogFooter>
+        </form>
+      </DialogContent>
+    </Dialog>
+  );
+}

src/app/page.tsx

@@ -15,6 +15,7 @@ import {
   PanelLeftClose,
   PanelRight,
   PanelRightClose,
+  KeyRound,
   LogOut,
 } from "lucide-react";
 import {
@@ -31,6 +32,7 @@ import { ScheduledTasksPanel } from "@/app/components/ScheduledTasksPanel";
 import { ThemeToggle } from "@/app/components/ThemeToggle";
 import { HealthIndicator } from "@/app/components/HealthIndicator";
 import { InspectorPanel } from "@/app/components/InspectorPanel";
+import { ChangePasswordDialog } from "@/app/components/ChangePasswordDialog";
 import { setThreadAutoApprove } from "@/lib/autoApprove";
 import type { MainChatReporter } from "@/lib/asyncAgents";
 import { cn } from "@/lib/utils";
@@ -71,6 +73,7 @@ function HomePageInner({
   const [notifyMainChat, setNotifyMainChat] = useState<MainChatReporter | null>(
     null
   );
+  const [changePasswordOpen, setChangePasswordOpen] = useState(false);
 
   const fetchAssistant = useCallback(async () => {
     const isUUID =
@@ -348,19 +351,34 @@ function HomePageInner({
             />
             <ThemeToggle />
             {authEnabled && (
-              <Button
-                variant="ghost"
-                size="icon"
-                onClick={signOut}
-                aria-label="Sign out"
-                title="Sign out"
-                className="size-8"
-              >
-                <LogOut
-                  className="size-4"
-                  aria-hidden="true"
-                />
-              </Button>
+              <>
+                <Button
+                  variant="ghost"
+                  size="icon"
+                  onClick={() => setChangePasswordOpen(true)}
+                  aria-label="Change password"
+                  title="Change password"
+                  className="size-8"
+                >
+                  <KeyRound
+                    className="size-4"
+                    aria-hidden="true"
+                  />
+                </Button>
+                <Button
+                  variant="ghost"
+                  size="icon"
+                  onClick={signOut}
+                  aria-label="Sign out"
+                  title="Sign out"
+                  className="size-8"
+                >
+                  <LogOut
+                    className="size-4"
+                    aria-hidden="true"
+                  />
+                </Button>
+              </>
             )}
             <Button
               variant="ghost"
@@ -539,6 +557,12 @@ function HomePageInner({
           </ResizablePanelGroup>
         </div>
       </div>
+      {authEnabled && (
+        <ChangePasswordDialog
+          open={changePasswordOpen}
+          onOpenChange={setChangePasswordOpen}
+        />
+      )}
     </>
   );
 }

src/lib/server/auth.ts

@@ -1,4 +1,9 @@
-import { createHmac, randomUUID, timingSafeEqual } from "crypto";
+import {
+  createHmac,
+  randomBytes,
+  randomUUID,
+  timingSafeEqual,
+} from "crypto";
 import { promises as fs } from "fs";
 import { homedir } from "os";
 import { join, resolve } from "path";
@@ -64,6 +69,53 @@ export function verifyCredentials(username: string, password: string): boolean {
   );
 }
 
+function envFilePath(): string {
+  return join(process.cwd(), ".env");
+}
+
+function replaceEnvValue(source: string, key: string, value: string): string {
+  const expression = new RegExp(`^${key}=.*$`, "m");
+  if (!expression.test(source)) {
+    throw new AuthConfigurationError(`${key} is missing from .env.`);
+  }
+  return source.replace(expression, `${key}=${JSON.stringify(value)}`);
+}
+
+/**
+ * Persist the new password and rotate the signing key. Rotating the key makes
+ * every old session invalid; the caller immediately issues a replacement cookie
+ * to the account that successfully supplied the current password.
+ */
+export async function updateAuthPassword(password: string): Promise<void> {
+  getAuthConfiguration();
+  const target = envFilePath();
+  let stat;
+  try {
+    stat = await fs.lstat(target);
+  } catch {
+    throw new AuthConfigurationError("The local .env file is not available.");
+  }
+  if (!stat.isFile() || stat.isSymbolicLink()) {
+    throw new AuthConfigurationError("The local .env file is not writable.");
+  }
+
+  const source = await fs.readFile(target, "utf8");
+  const nextSecret = randomBytes(32).toString("hex");
+  const next = replaceEnvValue(
+    replaceEnvValue(source, "WEBUI_AUTH_PASSWORD", password),
+    "WEBUI_AUTH_SECRET",
+    nextSecret
+  );
+  const temp = `${target}.${randomUUID()}.tmp`;
+  await fs.writeFile(temp, next, { encoding: "utf8", mode: 0o600 });
+  await fs.rename(temp, target);
+
+  // Next reloads .env on restart; update this process too so the new password
+  // and replacement session work immediately without waiting for a restart.
+  process.env.WEBUI_AUTH_PASSWORD = password;
+  process.env.WEBUI_AUTH_SECRET = nextSecret;
+}
+
 function encode(value: string): string {
   return Buffer.from(value).toString("base64url");
 }