fix: Redact SSO PII before deletion

openedx/core/djangoapps/user_api/accounts/__init__.py

@@ -6,6 +6,9 @@
 from django.utils.text import format_lazy
 from django.utils.translation import gettext_lazy as _
 
+# Import signals to ensure they are registered
+from . import signals  # noqa: F401, pylint: disable=unused-import
+
 # The maximum length for the bio ("about me") account field
 BIO_MAX_LENGTH = 300
 

openedx/core/djangoapps/user_api/accounts/signals.py

@@ -2,8 +2,24 @@
 Django Signal related functionality for user_api accounts
 """
 
+import logging
 
-from django.dispatch import Signal
+from django.db.models.signals import pre_delete
+from django.dispatch import Signal, receiver
+from social_django.models import UserSocialAuth
+
+from .utils import REDACTED_SOCIAL_AUTH_UID_PREFIX, REDACTED_SOCIAL_AUTH_UID_SUFFIX, redact_and_delete_social_auth
+
+logger = logging.getLogger(__name__)
+
+
+def get_redacted_social_auth_uid(pk):
+    """
+    Return the redacted uid for a UserSocialAuth record.
+
+    This must match the format used in redact_and_delete_social_auth.
+    """
+    return f'{REDACTED_SOCIAL_AUTH_UID_PREFIX}{pk}{REDACTED_SOCIAL_AUTH_UID_SUFFIX}'
 
 # Signal to retire a user from LMS-initiated mailings (course mailings, etc)
 # providing_args=["user"]
@@ -16,3 +32,23 @@
 # Signal to retire LMS misc information
 # providing_args=["user"]
 USER_RETIRE_LMS_MISC = Signal()
+
+
+@receiver(pre_delete, sender=UserSocialAuth)
+def redact_social_auth_pii_before_deletion(sender, instance, **kwargs):  # pylint: disable=unused-argument
+    """
+    Safety-net signal handler that redacts PII on any UserSocialAuth before deletion.
+
+    Records deleted via ``redact_and_delete_social_auth`` will already be redacted;
+    this handler is a fallback for any other deletion path.
+    """
+    redacted_uid = get_redacted_social_auth_uid(instance.pk)
+
+    # Safety-net in case the record wasn't redacted before delete.
+    if instance.extra_data or instance.uid != redacted_uid:
+        logger.warning(
+            'Social auth link for user_id=%s, provider=%s was deleted without first being redacted.',
+            instance.user_id,
+            instance.provider,
+        )
+        redact_and_delete_social_auth(instance.user_id, skip_delete=True)

openedx/core/djangoapps/user_api/accounts/tests/test_utils.py

@@ -6,10 +6,14 @@
 from completion.test_utils import CompletionWaffleTestMixin
 from django.test import TestCase
 from django.test.utils import override_settings
+from social_django.models import UserSocialAuth
 
 from common.djangoapps.student.models import CourseEnrollment
 from common.djangoapps.student.tests.factories import UserFactory
-from openedx.core.djangoapps.user_api.accounts.utils import retrieve_last_sitewide_block_completed
+from openedx.core.djangoapps.user_api.accounts.signals import get_redacted_social_auth_uid
+from openedx.core.djangoapps.user_api.accounts.utils import (
+    retrieve_last_sitewide_block_completed,
+)
 from openedx.core.djangolib.testing.utils import skip_unless_lms
 from xmodule.modulestore.tests.django_utils import (
     SharedModuleStoreTestCase,  # lint-amnesty, pylint: disable=wrong-import-order
@@ -133,3 +137,142 @@ def test_retrieve_last_sitewide_block_completed(self):
                )
 
         assert empty_block_url is None
+
+
+@skip_unless_lms
+class RedactUserSocialAuthPIITest(TestCase):
+    """
+    Tests for SSO PII redaction before deletion.
+    """
+
+    def setUp(self):
+        super().setUp()
+        self.user = UserFactory.create(username='testuser', email='testuser@example.com')
+
+    def create_social_auth(self, provider='google-oauth2', uid='user@example.com', extra_data=None):
+        """
+        Helper method to create UserSocialAuth instances for testing.
+        """
+        if extra_data is None:
+            extra_data = {
+                'email': 'user@example.com',
+                'name': 'Test User',
+                'id': '123456789',
+            }
+        return UserSocialAuth.objects.create(
+            user=self.user,
+            provider=provider,
+            uid=uid,
+            extra_data=extra_data,
+        )
+
+    def test_get_redacted_social_auth_uid_format(self):
+        """
+        Test that get_redacted_social_auth_uid returns the expected string format.
+
+        This is the single source of truth for the redacted uid format.
+        If this test breaks, the bulk retirement Concat/Cast in utils.py and
+        retire_user.py must also be updated to match.
+        """
+        assert get_redacted_social_auth_uid(42) == 'redacted-before-delete-42@safe.com'
+        assert get_redacted_social_auth_uid(1) == 'redacted-before-delete-1@safe.com'
+
+    def test_delete_redacts_user_social_auth_pii(self):
+        """
+        Test that deleting social auth redacts uid and extra_data before removal.
+        """
+        social_auth = self.create_social_auth()
+        social_auth_id = social_auth.id
+
+        captured_states = []
+
+        def capture_state_before_delete(sender, instance, **kwargs):  # pylint: disable=unused-argument
+            instance.refresh_from_db()
+            captured_states.append({
+                'id': instance.id,
+                'uid': instance.uid,
+                'extra_data': dict(instance.extra_data) if instance.extra_data else {},
+            })
+
+        from django.db.models.signals import pre_delete
+
+        pre_delete.connect(capture_state_before_delete, sender=UserSocialAuth)
+        try:
+            social_auth.delete()
+        finally:
+            pre_delete.disconnect(capture_state_before_delete, sender=UserSocialAuth)
+
+        assert captured_states == [{
+            'id': social_auth_id,
+            'uid': get_redacted_social_auth_uid(social_auth_id),
+            'extra_data': {},
+        }]
+        assert not UserSocialAuth.objects.filter(id=social_auth_id).exists()
+
+    def test_delete_already_redacted_user_social_auth_is_idempotent(self):
+        """
+        Test that deleting an already redacted social auth keeps the redacted state.
+        """
+        social_auth = self.create_social_auth()
+        social_auth.uid = get_redacted_social_auth_uid(social_auth.pk)
+        social_auth.extra_data = {}
+        social_auth.save(update_fields=['uid', 'extra_data'])
+        social_auth_id = social_auth.id
+
+        captured_states = []
+
+        def capture_state_before_delete(sender, instance, **kwargs):  # pylint: disable=unused-argument
+            instance.refresh_from_db()
+            captured_states.append((instance.uid, instance.extra_data))
+
+        from django.db.models.signals import pre_delete
+
+        pre_delete.connect(capture_state_before_delete, sender=UserSocialAuth)
+        try:
+            social_auth.delete()
+        finally:
+            pre_delete.disconnect(capture_state_before_delete, sender=UserSocialAuth)
+
+        assert captured_states == [
+            (get_redacted_social_auth_uid(social_auth_id), {}),
+        ]
+        assert not UserSocialAuth.objects.filter(id=social_auth_id).exists()
+
+    def test_delete_redacts_multiple_sso_providers(self):
+        """
+        Test that deletion redacts multiple SSO providers before removal.
+        """
+        auths = [
+            self.create_social_auth(
+                provider='google-oauth2',
+                uid='google@example.com',
+                extra_data={'email': 'google@example.com', 'name': 'Google User'}
+            ),
+            self.create_social_auth(
+                provider='tpa-saml',
+                uid='saml@example.com',
+                extra_data={'email': 'saml@example.com', 'name': 'SAML User', 'uid': 'saml-uid'}
+            ),
+        ]
+        # Save IDs before deletion (they become None after delete)
+        auth_ids = [auth.pk for auth in auths]
+
+        captured_states = []
+
+        def capture_state_before_delete(sender, instance, **kwargs):  # pylint: disable=unused-argument
+            instance.refresh_from_db()
+            captured_states.append((instance.provider, instance.uid, instance.extra_data))
+
+        from django.db.models.signals import pre_delete
+
+        pre_delete.connect(capture_state_before_delete, sender=UserSocialAuth)
+        try:
+            for auth in auths:
+                auth.delete()
+        finally:
+            pre_delete.disconnect(capture_state_before_delete, sender=UserSocialAuth)
+
+        assert sorted(captured_states) == sorted([
+            ('google-oauth2', get_redacted_social_auth_uid(auth_ids[0]), {}),
+            ('tpa-saml', get_redacted_social_auth_uid(auth_ids[1]), {}),
+        ])

openedx/core/djangoapps/user_api/accounts/utils.py

@@ -11,6 +11,8 @@
 from completion.models import BlockCompletion
 from completion.waffle import ENABLE_COMPLETION_TRACKING_SWITCH
 from django.conf import settings
+from django.db.models import CharField, Value
+from django.db.models.functions import Cast, Concat
 from django.utils.translation import gettext as _
 from edx_django_utils.user import generate_password
 from social_django.models import UserSocialAuth
@@ -23,6 +25,10 @@
 
 from ..models import UserRetirementStatus
 
+# Prefix and suffix used to build a per-record redacted uid for UserSocialAuth.
+REDACTED_SOCIAL_AUTH_UID_PREFIX = 'redacted-before-delete-'
+REDACTED_SOCIAL_AUTH_UID_SUFFIX = '@safe.com'
+
 ENABLE_SECONDARY_EMAIL_FEATURE_SWITCH = 'enable_secondary_email_feature'
 LOGGER = logging.getLogger(__name__)
 
@@ -196,6 +202,29 @@ def is_secondary_email_feature_enabled():
     return waffle.switch_is_active(ENABLE_SECONDARY_EMAIL_FEATURE_SWITCH)
 
 
+def redact_and_delete_social_auth(user_id, skip_delete=False):
+    """
+    Redact PII from all UserSocialAuth records for the given user, then delete them.
+
+    Redaction happens before deletion so that any observers see only sanitised data.
+    The uid format matches ``get_redacted_social_auth_uid()``.
+
+    ``skip_delete`` should only be set to True when called from the pre_delete signal
+    handler, where deletion is already in progress.
+    """
+    social_auth_queryset = UserSocialAuth.objects.filter(user_id=user_id)
+    social_auth_queryset.update(
+        uid=Concat(
+            Value(REDACTED_SOCIAL_AUTH_UID_PREFIX),
+            Cast('id', output_field=CharField()),
+            Value(REDACTED_SOCIAL_AUTH_UID_SUFFIX),
+        ),
+        extra_data={},
+    )
+    if not skip_delete:
+        social_auth_queryset.delete()
+
+
 def create_retirement_request_and_deactivate_account(user):
     """
     Adds user to retirement queue, unlinks social auth accounts, changes user passwords
@@ -204,8 +233,8 @@ def create_retirement_request_and_deactivate_account(user):
     # Add user to retirement queue.
     UserRetirementStatus.create_retirement(user)
 
-    # Unlink LMS social auth accounts
-    UserSocialAuth.objects.filter(user_id=user.id).delete()
+    # Redact and unlink LMS social auth accounts.
+    redact_and_delete_social_auth(user.id)
 
     # Change LMS password & email
     user.email = get_retired_email_by_email(user.email)

openedx/core/djangoapps/user_api/management/commands/retire_user.py

@@ -5,11 +5,11 @@
 from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
 from django.core.management.base import BaseCommand, CommandError
 from django.db import transaction
-from social_django.models import UserSocialAuth
 
 from common.djangoapps.student.models import AccountRecovery, Registration, get_retired_email_by_email
 from openedx.core.djangolib.oauth2_retirement_utils import retire_dot_oauth2_models
 
+from ...accounts.utils import redact_and_delete_social_auth
 from ...models import BulkUserRetirementConfig, UserRetirementStatus
 
 logger = logging.getLogger(__name__)
@@ -144,8 +144,8 @@ def handle(self, *args, **options):
                 for user in users:
                     # Add user to retirement queue.
                     UserRetirementStatus.create_retirement(user)
-                    # Unlink LMS social auth accounts
-                    UserSocialAuth.objects.filter(user_id=user.id).delete()
+                    # Redact and unlink LMS social auth accounts.
+                    redact_and_delete_social_auth(user.id)
                     # Change LMS password & email
                     user.email = get_retired_email_by_email(user.email)
                     user.set_unusable_password()