feat: IP & device rate limits

backend/apps/accounts/migrations/0005_phoneotp_device_signal_phoneotp_request_ip_and_more.py

@@ -0,0 +1,23 @@
+# Generated by Django 6.0.3 on 2026-03-13 21:54
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('accounts', '0004_alter_user_groups_alter_user_phone_number_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='phoneotp',
+            name='device_signal',
+            field=models.CharField(blank=True, db_index=True, default='', max_length=64),
+        ),
+        migrations.AddField(
+            model_name='phoneotp',
+            name='request_ip',
+            field=models.GenericIPAddressField(blank=True, db_index=True, null=True),
+        ),
+    ]

backend/apps/accounts/models.py

@@ -97,6 +97,9 @@ class PhoneOTP(models.Model):
     verified_at = models.DateTimeField(null=True, blank=True)
     attempt_count = models.PositiveSmallIntegerField(default=0)
     max_attempts = models.PositiveSmallIntegerField(default=5)
+    # Request metadata for abuse controls and support investigations.
+    request_ip = models.GenericIPAddressField(null=True, blank=True, db_index=True)
+    device_signal = models.CharField(max_length=64, blank=True, default="", db_index=True)
 
     def is_expired(self):
         return timezone.now() >= self.expires_at

backend/apps/accounts/serializers.py

@@ -62,6 +62,7 @@ class OTPVerifySerializer(serializers.Serializer):
 class PhoneAuthRequestSerializer(serializers.Serializer):
     phone_number = serializers.CharField(max_length=20)
     channel = serializers.ChoiceField(choices=OtpChannel.choices)
+    device_id = serializers.CharField(required=False, allow_blank=True, max_length=128, write_only=True)
     email = serializers.EmailField(required=False, allow_null=True, allow_blank=True)
     first_name = serializers.CharField(required=False, allow_blank=True)
     last_name = serializers.CharField(required=False, allow_blank=True)

backend/apps/accounts/services/otp.py

@@ -1,6 +1,8 @@
 import logging
 import os
 import secrets
+from hashlib import sha256
+import ipaddress
 from dataclasses import dataclass
 from datetime import timedelta
 
@@ -33,6 +35,18 @@ class OtpCooldownError(RuntimeError):
         self.retry_after_seconds = retry_after_seconds
 
 
+class OtpIpRateLimitError(RuntimeError):
+    def __init__(self, retry_after_seconds: int):
+        super().__init__(_("Too many OTP requests from this IP. Try again later."))
+        self.retry_after_seconds = retry_after_seconds
+
+
+class OtpDeviceRateLimitError(RuntimeError):
+    def __init__(self, retry_after_seconds: int):
+        super().__init__(_("Too many OTP requests from this device. Try again later."))
+        self.retry_after_seconds = retry_after_seconds
+
+
 class BaseOtpProvider:
     uses_provider_otp = False
 
@@ -166,7 +180,73 @@ def generate_code(length: int = 6) -> str:
     return "".join(secrets.choice(digits) for _ in range(length))
 
 
-def create_and_send_otp(phone_number: str, channel: str, purpose: str = OtpPurpose.AUTH) -> OtpSendResult:
+def _compute_retry_after_seconds(oldest_recent, now, window_minutes: int, floor_seconds: int = 1) -> int:
+    if oldest_recent:
+        retry_after = int((oldest_recent.created_at + timedelta(minutes=window_minutes) - now).total_seconds())
+    else:
+        retry_after = floor_seconds
+    return max(retry_after, floor_seconds)
+
+
+def normalize_request_ip(raw_ip: str | None) -> str | None:
+    if not raw_ip:
+        return None
+    candidate = raw_ip.split(",")[0].strip()
+    try:
+        return str(ipaddress.ip_address(candidate))
+    except ValueError:
+        return None
+
+
+def build_device_signal(device_id: str | None, user_agent: str | None, accept_language: str | None) -> str:
+    # Prefer explicit device id; fallback to passive headers for coarse signal.
+    source = (device_id or "").strip()
+    if not source:
+        source = f"{(user_agent or '').strip()}|{(accept_language or '').strip()}"
+    if not source.strip("|"):
+        return ""
+    return f"sha256:{sha256(source.encode('utf-8')).hexdigest()[:24]}"
+
+
+def enforce_phone_auth_request_limits(request_ip: str | None, device_signal: str | None) -> None:
+    now = timezone.now()
+    window_minutes = getattr(settings, "PHONE_AUTH_RISK_WINDOW_MINUTES", 15)
+    window_start = now - timedelta(minutes=window_minutes)
+    ip_limit = getattr(settings, "PHONE_AUTH_IP_MAX_PER_WINDOW", 20)
+    device_limit = getattr(settings, "PHONE_AUTH_DEVICE_MAX_PER_WINDOW", 20)
+
+    if request_ip and ip_limit > 0:
+        ip_recent = PhoneOTP.objects.filter(
+            purpose=OtpPurpose.AUTH,
+            request_ip=request_ip,
+            created_at__gte=window_start,
+        )
+        if ip_recent.count() >= ip_limit:
+            oldest_recent = ip_recent.order_by("created_at").first()
+            raise OtpIpRateLimitError(
+                retry_after_seconds=_compute_retry_after_seconds(oldest_recent, now, window_minutes)
+            )
+
+    if device_signal and device_limit > 0:
+        device_recent = PhoneOTP.objects.filter(
+            purpose=OtpPurpose.AUTH,
+            device_signal=device_signal,
+            created_at__gte=window_start,
+        )
+        if device_recent.count() >= device_limit:
+            oldest_recent = device_recent.order_by("created_at").first()
+            raise OtpDeviceRateLimitError(
+                retry_after_seconds=_compute_retry_after_seconds(oldest_recent, now, window_minutes)
+            )
+
+
+def create_and_send_otp(
+    phone_number: str,
+    channel: str,
+    purpose: str = OtpPurpose.AUTH,
+    request_ip: str | None = None,
+    device_signal: str = "",
+) -> OtpSendResult:
     provider = get_provider()
     now = timezone.now()
     window_minutes = getattr(settings, "OTP_WINDOW_MINUTES", 15)
@@ -177,11 +257,9 @@ def create_and_send_otp(phone_number: str, channel: str, purpose: str = OtpPurpo
     recent_qs = PhoneOTP.objects.filter(phone_number=phone_number, created_at__gte=window_start)
     if recent_qs.count() >= max_per_window:
         oldest_recent = recent_qs.order_by("created_at").first()
-        if oldest_recent:
+        raise OtpRateLimitError(
-            retry_after = int((oldest_recent.created_at + timedelta(minutes=window_minutes) - now).total_seconds())
+            retry_after_seconds=_compute_retry_after_seconds(oldest_recent, now, window_minutes, cooldown_seconds)
-        else:
+        )
-            retry_after = cooldown_seconds
-        raise OtpRateLimitError(retry_after_seconds=max(retry_after, cooldown_seconds))
 
     latest = (
         PhoneOTP.objects.filter(phone_number=phone_number, channel=channel)
@@ -210,6 +288,8 @@ def create_and_send_otp(phone_number: str, channel: str, purpose: str = OtpPurpo
         provider=settings.OTP_PROVIDER,
         code_hash=code_hash,
         expires_at=PhoneOTP.expiry_at(),
+        request_ip=request_ip,
+        device_signal=device_signal,
     )
 
     if provider.uses_provider_otp:

backend/apps/accounts/tests/test_phone_auth_request_contract.py

@@ -167,3 +167,68 @@ def test_phone_auth_request_rate_limit_returns_retry_after(client):
     data = second.json()
     assert "detail" in data
     assert data["retry_after_seconds"] > 0
+
+
+@pytest.mark.django_db
+@override_settings(
+    OTP_PROVIDER="console",
+    OTP_MAX_PER_WINDOW=20,
+    OTP_WINDOW_MINUTES=15,
+    OTP_RESEND_COOLDOWN_SECONDS=0,
+    PHONE_AUTH_RISK_WINDOW_MINUTES=15,
+    PHONE_AUTH_IP_MAX_PER_WINDOW=2,
+    PHONE_AUTH_DEVICE_MAX_PER_WINDOW=20,
+)
+def test_phone_auth_request_ip_throttle_returns_retry_after(client):
+    with patch("apps.accounts.services.otp.generate_code", return_value="123456"):
+        first = client.post(
+            reverse("phone_auth_request"),
+            {"phone_number": "0512345678", "channel": "sms"},
+            content_type="application/json",
+            REMOTE_ADDR="203.0.113.10",
+        )
+        assert first.status_code == 201
+
+        second = client.post(
+            reverse("phone_auth_request"),
+            {"phone_number": "0512345679", "channel": "sms"},
+            content_type="application/json",
+            REMOTE_ADDR="203.0.113.10",
+        )
+        assert second.status_code == 201
+
+        third = client.post(
+            reverse("phone_auth_request"),
+            {"phone_number": "0512345680", "channel": "sms"},
+            content_type="application/json",
+            REMOTE_ADDR="203.0.113.10",
+        )
+
+    assert third.status_code == 429
+    data = third.json()
+    assert "detail" in data
+    assert data["retry_after_seconds"] > 0
+
+
+@pytest.mark.django_db
+@override_settings(
+    OTP_PROVIDER="console",
+    OTP_RESEND_COOLDOWN_SECONDS=0,
+    OTP_MAX_PER_WINDOW=20,
+    PHONE_AUTH_IP_MAX_PER_WINDOW=20,
+    PHONE_AUTH_DEVICE_MAX_PER_WINDOW=20,
+)
+def test_phone_auth_request_persists_request_ip_and_device_signal(client):
+    with patch("apps.accounts.services.otp.generate_code", return_value="123456"):
+        response = client.post(
+            reverse("phone_auth_request"),
+            {"phone_number": "0512345678", "channel": "sms", "device_id": "device-abc"},
+            content_type="application/json",
+            REMOTE_ADDR="198.51.100.40",
+            HTTP_USER_AGENT="pytest-agent",
+        )
+
+    assert response.status_code == 201
+    otp = PhoneOTP.objects.get(id=response.json()["request_id"])
+    assert otp.request_ip == "198.51.100.40"
+    assert otp.device_signal

backend/apps/accounts/views.py

@@ -16,8 +16,13 @@ from apps.accounts.serializers import (
 )
 from apps.accounts.services.otp import (
     OtpCooldownError,
+    OtpDeviceRateLimitError,
+    OtpIpRateLimitError,
     OtpRateLimitError,
+    build_device_signal,
     create_and_send_otp,
+    enforce_phone_auth_request_limits,
+    normalize_request_ip,
     verify_otp,
 )
 
@@ -93,6 +98,25 @@ class PhoneAuthRequestView(APIView):
         data = serializer.validated_data
         phone_number = data["phone_number"]
         email = data.get("email") or None
+        request_ip = normalize_request_ip(request.META.get("HTTP_X_FORWARDED_FOR") or request.META.get("REMOTE_ADDR"))
+        device_signal = build_device_signal(
+            data.get("device_id"),
+            request.META.get("HTTP_USER_AGENT"),
+            request.META.get("HTTP_ACCEPT_LANGUAGE"),
+        )
+
+        try:
+            enforce_phone_auth_request_limits(request_ip=request_ip, device_signal=device_signal)
+        except OtpIpRateLimitError as exc:
+            return Response(
+                {"detail": str(exc), "retry_after_seconds": exc.retry_after_seconds},
+                status=status.HTTP_429_TOO_MANY_REQUESTS,
+            )
+        except OtpDeviceRateLimitError as exc:
+            return Response(
+                {"detail": str(exc), "retry_after_seconds": exc.retry_after_seconds},
+                status=status.HTTP_429_TOO_MANY_REQUESTS,
+            )
 
         user = User.objects.filter(phone_number=phone_number).first()
         if not user:
@@ -110,7 +134,13 @@ class PhoneAuthRequestView(APIView):
             )
 
         try:
-            result = create_and_send_otp(phone_number, data["channel"], purpose=OtpPurpose.AUTH)
+            result = create_and_send_otp(
+                phone_number,
+                data["channel"],
+                purpose=OtpPurpose.AUTH,
+                request_ip=request_ip,
+                device_signal=device_signal,
+            )
         except OtpCooldownError as exc:
             return Response(
                 {"detail": str(exc), "retry_after_seconds": exc.retry_after_seconds},

backend/salon_api/settings.py

@@ -146,6 +146,9 @@ OTP_EXPIRY_MINUTES = int(os.getenv("OTP_EXPIRY_MINUTES", "5"))
 OTP_MAX_PER_WINDOW = int(os.getenv("OTP_MAX_PER_WINDOW", "5"))
 OTP_WINDOW_MINUTES = int(os.getenv("OTP_WINDOW_MINUTES", "15"))
 OTP_RESEND_COOLDOWN_SECONDS = int(os.getenv("OTP_RESEND_COOLDOWN_SECONDS", "60"))
+PHONE_AUTH_RISK_WINDOW_MINUTES = int(os.getenv("PHONE_AUTH_RISK_WINDOW_MINUTES", "15"))
+PHONE_AUTH_IP_MAX_PER_WINDOW = int(os.getenv("PHONE_AUTH_IP_MAX_PER_WINDOW", "20"))
+PHONE_AUTH_DEVICE_MAX_PER_WINDOW = int(os.getenv("PHONE_AUTH_DEVICE_MAX_PER_WINDOW", "20"))
 DEFAULT_CURRENCY = os.getenv("DEFAULT_CURRENCY", "SAR")
 NOTIFICATION_PROVIDER = os.getenv("NOTIFICATION_PROVIDER", OTP_PROVIDER)
 NOTIFICATION_DEFAULT_CHANNEL = os.getenv("NOTIFICATION_DEFAULT_CHANNEL", "sms")