Add rate limiting to OTP login attempts and update email template for conciseness

src/interface/web/app/components/loginPrompt/loginPrompt.tsx

@@ -36,6 +36,8 @@ export interface LoginPromptProps {
 
 const fetcher = (url: string) => fetch(url).then((res) => res.json());
 
+const ALLOWED_OTP_ATTEMPTS = 5;
+
 interface Provider {
     client_id: string;
     redirect_uri: string;
@@ -230,10 +232,16 @@ function EmailSignInContext({
 }) {
     const [otp, setOTP] = useState("");
     const [otpError, setOTPError] = useState("");
+    const [numFailures, setNumFailures] = useState(0);
 
     function checkOTPAndRedirect() {
         const verifyUrl = `/auth/magic?code=${otp}&email=${email}`;
 
+        if (numFailures >= ALLOWED_OTP_ATTEMPTS) {
+            setOTPError("Too many failed attempts. Please try again tomorrow.");
+            return;
+        }
+
         fetch(verifyUrl, {
             method: "GET",
             headers: {
@@ -246,8 +254,16 @@ function EmailSignInContext({
                     if (res.redirected) {
                         window.location.href = res.url;
                     }
+                } else if (res.status === 401) {
+                    setOTPError("Invalid OTP.");
+                    setNumFailures(numFailures + 1);
+                    if (numFailures + 1 >= ALLOWED_OTP_ATTEMPTS) {
+                        setOTPError("Too many failed attempts. Please try again tomorrow.");
+                    }
+                } else if (res.status === 429) {
+                    setOTPError("Too many failed attempts. Please try again tomorrow.");
+                    setNumFailures(ALLOWED_OTP_ATTEMPTS);
                 } else {
-                    setOTPError("Invalid OTP");
                     throw new Error("Failed to verify OTP");
                 }
             })
@@ -309,6 +325,7 @@ function EmailSignInContext({
                         maxLength={6}
                         value={otp || ""}
                         onChange={setOTP}
+                        disabled={numFailures >= ALLOWED_OTP_ATTEMPTS}
                         onComplete={() =>
                             setTimeout(() => {
                                 checkOTPAndRedirect();
@@ -324,7 +341,11 @@ function EmailSignInContext({
                             <InputOTPSlot index={5} />
                         </InputOTPGroup>
                     </InputOTP>
-                    <div className="text-red-500 text-sm">{otpError}</div>
+                    {otpError && (
+                        <div className="text-red-500 text-sm">
+                            {otpError} {ALLOWED_OTP_ATTEMPTS - numFailures} remaining attempts.
+                        </div>
+                    )}
                 </div>
             )}
 

src/khoj/database/adapters/__init__.py

@@ -437,10 +437,14 @@ def is_user_subscribed(user: KhojUser) -> bool:
     return subscribed
 
 
-async def get_user_by_email(email: str) -> KhojUser:
+async def aget_user_by_email(email: str) -> KhojUser:
     return await KhojUser.objects.filter(email=email).afirst()
 
 
+def get_user_by_email(email: str) -> KhojUser:
+    return KhojUser.objects.filter(email=email).first()
+
+
 async def aget_user_by_uuid(uuid: str) -> KhojUser:
     return await KhojUser.objects.filter(uuid=uuid).afirst()
 

src/khoj/interface/email/magic_link.html

@@ -16,12 +16,12 @@
             <img src="https://assets.khoj.dev/khoj_logo.png" alt="Khoj Logo" style="width: 120px;">
         </a>
 
-        <p style="font-size: 16px; color: #333; margin-bottom: 20px;">Hi!</p>
-
         <p style="font-size: 16px; color: #333; margin-bottom: 20px;">Use this code (valid for 5 minutes) to login to Khoj:</p>
 
         <h1 style="font-size: 24px; color: #2c3e50; margin-bottom: 20px; text-align: center;">{{ code }}</h1>
 
+        <p style="font-size: 16px; color: #333; margin-bottom: 20px;">It will be valid for 5 minutes.</p>
+
         <p style="font-size: 16px; color: #333; margin-bottom: 20px;">Alternatively, <a href="{{ link }}" target="_blank"
                 style="color: #FFA07A; text-decoration: none; font-weight: bold;">Click here to sign in on this
                 browser.</a></p>

src/khoj/routers/auth.py

@@ -5,7 +5,7 @@ import os
 from typing import Optional
 
 import requests
-from fastapi import APIRouter
+from fastapi import APIRouter, Depends
 from pydantic import BaseModel, EmailStr
 from starlette.authentication import requires
 from starlette.config import Config
@@ -22,7 +22,11 @@ from khoj.database.adapters import (
     get_or_create_user,
 )
 from khoj.routers.email import send_magic_link_email, send_welcome_email
-from khoj.routers.helpers import get_next_url, update_telemetry_state
+from khoj.routers.helpers import (
+    EmailVerificationApiRateLimiter,
+    get_next_url,
+    update_telemetry_state,
+)
 from khoj.utils import state
 
 logger = logging.getLogger(__name__)
@@ -99,7 +103,14 @@ async def login_magic_link(request: Request, form: MagicLinkForm):
 
 
 @auth_router.get("/magic")
-async def sign_in_with_magic_link(request: Request, code: str, email: str):
+async def sign_in_with_magic_link(
+    request: Request,
+    code: str,
+    email: str,
+    rate_limiter=Depends(
+        EmailVerificationApiRateLimiter(requests=10, window=60 * 60 * 24, slug="magic_link_verification")
+    ),
+):
     user = await aget_user_validated_by_email_verification_code(code, email)
     if user:
         id_info = {
@@ -108,7 +119,7 @@ async def sign_in_with_magic_link(request: Request, code: str, email: str):
 
         request.session["user"] = dict(id_info)
         return RedirectResponse(url="/")
-    return RedirectResponse(request.app.url_path_for("login_page"))
+    return Response(status_code=401)
 
 
 @auth_router.post("/token")

src/khoj/routers/email.py

@@ -47,7 +47,7 @@ async def send_magic_link_email(email, unique_id, host):
         {
             "sender": os.environ.get("RESEND_EMAIL", "noreply@khoj.dev"),
             "to": email,
-            "subject": f"{unique_id} - Sign in to Khoj 🚀",
+            "subject": f"Your unique login to Khoj",
             "html": html_content,
         }
     )

src/khoj/routers/helpers.py

@@ -49,6 +49,7 @@ from khoj.database.adapters import (
     ais_user_subscribed,
     create_khoj_token,
     get_khoj_tokens,
+    get_user_by_email,
     get_user_name,
     get_user_notion_config,
     get_user_subscription_state,
@@ -1363,6 +1364,49 @@ class FeedbackData(BaseModel):
     sentiment: str
 
 
+class EmailVerificationApiRateLimiter:
+    def __init__(self, requests: int, window: int, slug: str):
+        self.requests = requests
+        self.window = window
+        self.slug = slug
+
+    def __call__(self, request: Request):
+        # Rate limiting disabled if billing is disabled
+        if state.billing_enabled is False:
+            return
+
+        # Extract the email query parameter
+        email = request.query_params.get("email")
+
+        if email:
+            logger.info(f"Email query parameter: {email}")
+
+        user: KhojUser = get_user_by_email(email)
+
+        if not user:
+            raise HTTPException(
+                status_code=404,
+                detail="User not found.",
+            )
+
+        # Remove requests outside of the time window
+        cutoff = datetime.now(tz=timezone.utc) - timedelta(seconds=self.window)
+        count_requests = UserRequests.objects.filter(user=user, created_at__gte=cutoff, slug=self.slug).count()
+
+        # Check if the user has exceeded the rate limit
+        if count_requests >= self.requests:
+            logger.info(
+                f"Rate limit: {count_requests}/{self.requests} requests not allowed in {self.window} seconds for email: {email}."
+            )
+            raise HTTPException(
+                status_code=429,
+                detail="Ran out of login attempts",
+            )
+
+        # Add the current request to the db
+        UserRequests.objects.create(user=user, slug=self.slug)
+
+
 class ApiUserRateLimiter:
     def __init__(self, requests: int, subscribed_requests: int, window: int, slug: str):
         self.requests = requests