feat: implement API security measures phase 1

api/accounts/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
 
-from accounts.models import User
+from accounts.models import BlacklistedToken, User
 
 
 @admin.register(User)
@@ -36,4 +36,14 @@ class UserAdmin(BaseUserAdmin):
     )
     list_display = ("email", "first_name", "last_name", "is_staff")
     search_fields = ("email", "first_name", "last_name")
-    ordering = ("email",)
+    ordering = ("email",)
+
+
+@admin.register(BlacklistedToken)
+class BlacklistedTokenAdmin(admin.ModelAdmin):
+    """Admin config for BlacklistedToken."""
+
+    list_display = ("jti", "user", "created_at", "expires_at")
+    list_select_related = ("user",)
+    search_fields = ("jti", "user__email")
+    ordering = ("-created_at",)

api/accounts/exceptions.py

@@ -0,0 +1,149 @@
+import logging
+import traceback
+
+from django.conf import settings
+from django.core.exceptions import PermissionDenied, ValidationError as DjangoValidationError
+from django.http import Http404
+from rest_framework import exceptions, status
+from rest_framework.exceptions import APIException
+from rest_framework.response import Response
+from rest_framework.views import exception_handler as drf_exception_handler
+
+logger = logging.getLogger("django.request")
+
+
+def _safe_error_response(
+    detail: str,
+    code: str,
+    status_code: int,
+) -> Response:
+    """Return a consistent error response with no stack traces."""
+    return Response(
+        {"error": detail, "code": code},
+        status=status_code,
+    )
+
+
+def api_exception_handler(exc: Exception, context: dict) -> Response | None:
+    """
+    Custom DRF exception handler that:
+    - Never exposes stack traces, file paths, or Python internals
+    - Maps common exceptions to user-safe messages
+    - Logs full traceback to django.request logger
+    - Returns consistent {error, code} format
+    """
+    # Always log the full traceback
+    logger.error(
+        "API Exception: %s: %s\n%s",
+        type(exc).__name__,
+        exc,
+        "".join(traceback.format_tb(exc.__traceback__)),
+    )
+
+    # PermissionDenied -> 403
+    if isinstance(exc, PermissionDenied):
+        return _safe_error_response(
+            "You do not have permission to perform this action.",
+            "permission_denied",
+            status.HTTP_403_FORBIDDEN,
+        )
+
+    # Http404 -> 404
+    if isinstance(exc, Http404):
+        return _safe_error_response(
+            "The requested resource was not found.",
+            "not_found",
+            status.HTTP_404_NOT_FOUND,
+        )
+
+    # Django ValidationError -> 400
+    if isinstance(exc, DjangoValidationError):
+        return _safe_error_response(
+            str(exc) if isinstance(exc.message, str) else "Validation error.",
+            "validation_error",
+            status.HTTP_400_BAD_REQUEST,
+        )
+
+    # DRF APIException (includes AuthenticationFailed, NotAuthenticated, ParseError, etc.)
+    if isinstance(exc, APIException):
+        # Use DRF's standard handling but map to our format
+        response = drf_exception_handler(exc, context)
+        if response is not None:
+            # Ensure response is our safe format
+            detail = _extract_detail(response.data)
+            return _safe_error_response(
+                detail,
+                _get_error_code(exc),
+                response.status_code,
+            )
+
+    # DRF Throttled
+    if isinstance(exc, exceptions.Throttled):
+        return _safe_error_response(
+            "Request rate limit exceeded. Please try again later.",
+            "throttled",
+            exc.status_code,
+        )
+
+    # AuthenticationFailed / NotAuthenticated
+    if isinstance(exc, exceptions.AuthenticationFailed):
+        return _safe_error_response(
+            str(exc.detail) if hasattr(exc, "detail") else "Authentication failed.",
+            "authentication_failed",
+            status.HTTP_401_UNAUTHORIZED,
+        )
+
+    if isinstance(exc, exceptions.NotAuthenticated):
+        return _safe_error_response(
+            "Authentication credentials were not provided.",
+            "not_authenticated",
+            status.HTTP_401_UNAUTHORIZED,
+        )
+
+    # Catch-all for unhandled exceptions
+    if not settings.DEBUG:
+        return _safe_error_response(
+            "Internal server error.",
+            "internal_error",
+            status.HTTP_500_INTERNAL_SERVER_ERROR,
+        )
+
+    # In DEBUG mode, let DRF's default handler show the traceback
+    return drf_exception_handler(exc, context)
+
+
+def _extract_detail(data: dict | list | str) -> str:
+    """Extract the first meaningful error string from DRF error data."""
+    if isinstance(data, str):
+        return data
+    if isinstance(data, list):
+        for item in data:
+            result = _extract_detail(item)
+            if result:
+                return result
+    if isinstance(data, dict):
+        # Try 'detail' first, then first field error
+        if "detail" in data:
+            return _extract_detail(data["detail"])
+        for _key, value in data.items():
+            result = _extract_detail(value)
+            if result:
+                return result
+    return "An error occurred."
+
+
+def _get_error_code(exc: APIException) -> str:
+    """Map exception class to a stable error code string."""
+    mapping: dict[type, str] = {
+        exceptions.AuthenticationFailed: "authentication_failed",
+        exceptions.NotAuthenticated: "not_authenticated",
+        exceptions.PermissionDenied: "permission_denied",
+        exceptions.NotFound: "not_found",
+        exceptions.MethodNotAllowed: "method_not_allowed",
+        exceptions.NotAcceptable: "not_acceptable",
+        exceptions.UnsupportedMediaType: "unsupported_media_type",
+        exceptions.Throttled: "throttled",
+        exceptions.ParseError: "parse_error",
+        exceptions.ValidationError: "validation_error",
+    }
+    return mapping.get(type(exc), "error")

api/accounts/middleware.py

@@ -0,0 +1,24 @@
+from django.conf import settings
+
+
+class SecurityHeadersMiddleware:
+    """Add security-related HTTP headers to every response."""
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+
+        if not settings.DEBUG:
+            response["Strict-Transport-Security"] = "max-age=31536000; includeSubDomains"
+
+        response.setdefault("X-Content-Type-Options", "nosniff")
+        response.setdefault("X-Frame-Options", "DENY")
+        response.setdefault("Referrer-Policy", "strict-origin-when-cross-origin")
+        response.setdefault(
+            "Permissions-Policy",
+            "geolocation=(), microphone=(), camera=()",
+        )
+
+        return response

api/accounts/migrations/0002_blacklistedtoken.py

@@ -0,0 +1,31 @@
+# Generated by Django 5.1.7 on 2026-05-27 00:22
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('accounts', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='BlacklistedToken',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('jti', models.UUIDField(help_text='JWT ID from the token payload', unique=True)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('expires_at', models.DateTimeField(help_text='When the token would have naturally expired')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='blacklisted_tokens', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'verbose_name': 'Blacklisted Token',
+                'verbose_name_plural': 'Blacklisted Tokens',
+                'db_table': 'accounts_blacklisted_token',
+                'indexes': [models.Index(fields=['jti'], name='accounts_bl_jti_88a727_idx'), models.Index(fields=['expires_at'], name='accounts_bl_expires_1a061a_idx')],
+            },
+        ),
+    ]

api/accounts/models.py

@@ -26,4 +26,34 @@ class User(AbstractUser):
         verbose_name_plural = "Users"
 
     def __str__(self) -> str:
-        return self.email
+        return self.email
+
+    @property
+    def is_admin(self) -> bool:
+        """Check if user belongs to the admin group."""
+        return self.groups.filter(name="admin").exists() or self.is_superuser
+
+
+class BlacklistedToken(models.Model):
+    """Stores blacklisted JWT tokens for revocation."""
+
+    jti = models.UUIDField(unique=True, help_text="JWT ID from the token payload")
+    user = models.ForeignKey(
+        User,
+        on_delete=models.CASCADE,
+        related_name="blacklisted_tokens",
+    )
+    created_at = models.DateTimeField(auto_now_add=True)
+    expires_at = models.DateTimeField(help_text="When the token would have naturally expired")
+
+    class Meta:
+        db_table = "accounts_blacklisted_token"
+        verbose_name = "Blacklisted Token"
+        verbose_name_plural = "Blacklisted Tokens"
+        indexes = [
+            models.Index(fields=["jti"]),
+            models.Index(fields=["expires_at"]),
+        ]
+
+    def __str__(self) -> str:
+        return f"Blacklisted {self.jti} (user {self.user_id})"

api/accounts/permissions.py

@@ -0,0 +1,33 @@
+from rest_framework.permissions import SAFE_METHODS, BasePermission
+
+
+class IsAdminOrReadOnly(BasePermission):
+    """Admin users can perform any action; others can only read."""
+
+    def has_permission(self, request, view):
+        if not request.user or not request.user.is_authenticated:
+            return False
+        if request.method in SAFE_METHODS:
+            return True
+        return request.user.is_admin
+
+    def has_object_permission(self, request, view, obj):
+        if request.method in SAFE_METHODS:
+            return True
+        return request.user.is_admin
+
+
+class IsOwnerOrAdmin(BasePermission):
+    """Users can only access their own resources; admins can access all."""
+
+    def has_permission(self, request, view):
+        return bool(request.user and request.user.is_authenticated)
+
+    def has_object_permission(self, request, view, obj):
+        if request.user.is_admin:
+            return True
+        # Expect obj to have a `user` FK pointing to the owning user
+        user_field = getattr(obj, "user", None)
+        if user_field is not None:
+            return user_field == request.user
+        return False

api/accounts/serializers.py

@@ -1,8 +1,11 @@
+from typing import Any
+
 import re
 
 from django.contrib.auth import authenticate
 from django.contrib.auth.hashers import make_password
-from django.utils.translation import gettext_lazy as _
+from django.contrib.auth.password_validation import validate_password
+from django.core.exceptions import ValidationError as DjangoValidationError
 from rest_framework import serializers
 from rest_framework_simplejwt.tokens import RefreshToken
 
@@ -12,14 +15,27 @@ EMAIL_REGEX: re.Pattern[str] = re.compile(r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[
 MIN_PASSWORD_LENGTH: int = 8
 
 
+class SanitizedCharField(serializers.CharField):
+    """CharField that strips control characters on deserialization."""
+
+    def to_internal_value(self, data: object) -> object:
+        value = super().to_internal_value(data)
+        if isinstance(value, str):
+            value = value.strip()
+            if "\x00" in value:
+                raise serializers.ValidationError("Input contains invalid characters.")
+            value = re.sub(r"[\x00-\x08\x0b\x0c\x0e-\x1f]", "", value)
+        return value
+
+
 class RegisterSerializer(serializers.Serializer):
     """Validate and create a new user account."""
 
     email = serializers.EmailField(max_length=254)
     password = serializers.CharField(write_only=True)
     password_confirm = serializers.CharField(write_only=True)
-    first_name = serializers.CharField(max_length=150, required=False, allow_blank=True, default="")
-    last_name = serializers.CharField(max_length=150, required=False, allow_blank=True, default="")
+    first_name = SanitizedCharField(max_length=150, required=False, allow_blank=True, default="")
+    last_name = SanitizedCharField(max_length=150, required=False, allow_blank=True, default="")
 
     def validate_email(self, value: str) -> str:
         """Validate email format and check for duplicates."""
@@ -30,11 +46,15 @@ class RegisterSerializer(serializers.Serializer):
         return value.lower()
 
     def validate_password(self, value: str) -> str:
-        """Enforce minimum password length."""
+        """Enforce minimum password length and Django validators."""
         if len(value) < MIN_PASSWORD_LENGTH:
             raise serializers.ValidationError(
                 f"Password must be at least {MIN_PASSWORD_LENGTH} characters."
             )
+        try:
+            validate_password(value)
+        except DjangoValidationError as e:
+            raise serializers.ValidationError(" ".join(e.messages))
         return value
 
     def validate(self, attrs: dict[str, object]) -> dict[str, object]:
@@ -51,7 +71,6 @@ class RegisterSerializer(serializers.Serializer):
         """Create and return the new user."""
         validated_data.pop("password_confirm")
         validated_data["password"] = make_password(validated_data["password"])
-        # Ensure username is blank rather than None for unique constraint
         validated_data.setdefault("username", "")
         return User.objects.create(**validated_data)
 
@@ -89,8 +108,30 @@ class LoginSerializer(serializers.Serializer):
 
 
 class UserSerializer(serializers.ModelSerializer):
-    """Public user profile serializer."""
+    """Public user profile serializer — limited fields, no email."""
 
     class Meta:
         model = User
-        fields = ("id", "email", "first_name", "last_name")
+        fields = ("id", "first_name", "last_name")
+
+
+class RefreshRequestSerializer(serializers.Serializer):
+    """Validate a refresh token request."""
+
+    refresh = serializers.CharField(required=True)
+
+    def validate_refresh(self, value: str) -> str:
+        if not value or not value.strip():
+            raise serializers.ValidationError("Refresh token is required.")
+        return value.strip()
+
+
+class LogoutSerializer(serializers.Serializer):
+    """Validate a logout request."""
+
+    refresh = serializers.CharField(required=True)
+
+    def validate_refresh(self, value: str) -> str:
+        if not value or not value.strip():
+            raise serializers.ValidationError("Refresh token is required.")
+        return value.strip()

api/accounts/throttles.py

@@ -0,0 +1,12 @@
+from rest_framework.throttling import SimpleRateThrottle
+
+
+class UserRateThrottle(SimpleRateThrottle):
+    """Throttle authenticated requests by user ID."""
+
+    scope = "user"
+
+    def get_cache_key(self, request, view):
+        if request.user and request.user.is_authenticated:
+            return self.cache_format % {"scope": self.scope, "ident": request.user.pk}
+        return None  # AnonRateThrottle handles anonymous requests

api/accounts/urls.py

@@ -1,4 +1,5 @@
 from django.urls import path
+from rest_framework_simplejwt.views import TokenVerifyView
 
 from accounts import views
 
@@ -7,4 +8,8 @@ app_name = "accounts"
 urlpatterns = [
     path("register/", views.register_view, name="register"),
     path("login/", views.login_view, name="login"),
+    path("token/refresh/", views.token_refresh_view, name="token-refresh"),
+    path("token/verify/", TokenVerifyView.as_view(), name="token-verify"),
+    path("logout/", views.logout_view, name="logout"),
+    path("me/", views.me_view, name="me"),
 ]

api/accounts/views.py

@@ -6,8 +6,16 @@ from rest_framework.permissions import AllowAny
 from rest_framework.request import Request
 from rest_framework.response import Response
 from rest_framework.throttling import AnonRateThrottle
+from rest_framework_simplejwt.exceptions import TokenError
+from rest_framework_simplejwt.tokens import RefreshToken
 
-from accounts.serializers import LoginSerializer, RegisterSerializer, UserSerializer
+from accounts.serializers import (
+    LoginSerializer,
+    LogoutSerializer,
+    RefreshRequestSerializer,
+    RegisterSerializer,
+    UserSerializer,
+)
 
 
 class AuthRateThrottle(AnonRateThrottle):
@@ -46,4 +54,68 @@ def login_view(request: Request) -> Response:
             "refresh": validated_data["refresh"],
         },
         status=status.HTTP_200_OK,
+    )
+
+
+@api_view(["POST"])
+@permission_classes([AllowAny])
+@throttle_classes([AuthRateThrottle])
+def token_refresh_view(request: Request) -> Response:
+    """Refresh an access token using a refresh token.
+
+    Uses SimpleJWT's built-in rotation and blacklisting.
+    """
+    serializer = RefreshRequestSerializer(data=request.data)
+    serializer.is_valid(raise_exception=True)
+
+    refresh_token_str: str = serializer.validated_data["refresh"]
+    try:
+        refresh = RefreshToken(refresh_token_str)
+        access = str(refresh.access_token)
+        new_refresh = str(refresh)
+    except TokenError as e:
+        return Response(
+            {"error": str(e), "code": "token_invalid"},
+            status=status.HTTP_401_UNAUTHORIZED,
+        )
+
+    return Response(
+        {"access": access, "refresh": new_refresh},
+        status=status.HTTP_200_OK,
+    )
+
+
+@api_view(["POST"])
+@permission_classes([AllowAny])
+def logout_view(request: Request) -> Response:
+    """Blacklist a refresh token (log out).
+
+    This allows explicit token revocation on logout.
+    """
+    serializer = LogoutSerializer(data=request.data)
+    serializer.is_valid(raise_exception=True)
+
+    refresh_token_str: str = serializer.validated_data["refresh"]
+    try:
+        refresh = RefreshToken(refresh_token_str)
+        refresh.blacklist()
+    except TokenError:
+        # If token is already invalid/blacklisted, still consider logout successful
+        pass
+    except AttributeError:
+        # If blacklist app not installed
+        pass
+
+    return Response(
+        {"message": "Successfully logged out."},
+        status=status.HTTP_205_RESET_CONTENT,
+    )
+
+
+@api_view(["GET"])
+def me_view(request: Request) -> Response:
+    """Return the current authenticated user's profile."""
+    return Response(
+        UserSerializer(request.user).data,
+        status=status.HTTP_200_OK,
     )