Fix GHSA-386h-chg4-cfw9

src/documents/serialisers.py

@@ -75,6 +75,7 @@ from documents.parsers import is_mime_type_supported
 from documents.permissions import get_document_count_filter_for_user
 from documents.permissions import get_groups_with_only_permission
 from documents.permissions import get_objects_for_user_owner_aware
+from documents.permissions import has_perms_owner_aware
 from documents.permissions import set_permissions_for_object
 from documents.regex import validate_regex_pattern
 from documents.templating.filepath import validate_filepath_template_and_render
@@ -2179,6 +2180,17 @@ class ShareLinkSerializer(OwnedObjectSerializer):
         validated_data["slug"] = get_random_string(50)
         return super().create(validated_data)
 
+    def validate_document(self, document):
+        if self.user is not None and has_perms_owner_aware(
+            self.user,
+            "view_document",
+            document,
+        ):
+            return document
+        raise PermissionDenied(
+            _("Insufficient permissions."),
+        )
+
 
 class BulkEditObjectsSerializer(SerializerWithPerms, SetPermissionsMixin):
     objects = serializers.ListField(

src/documents/tests/test_api_documents.py

@@ -2905,6 +2905,54 @@ class TestDocumentApi(DirectoriesMixin, DocumentConsumeDelayMixin, APITestCase):
         )
         self.assertEqual(resp.status_code, status.HTTP_200_OK)
 
+    def test_create_share_link_requires_view_permission_for_document(self):
+        """
+        GIVEN:
+            - A user with add_sharelink but without view permission on a document
+        WHEN:
+            - API request is made to create a share link for that document
+        THEN:
+            - Share link creation is denied until view permission is granted
+        """
+        user1 = User.objects.create_user(username="test1")
+        user1.user_permissions.add(*Permission.objects.filter(codename="add_sharelink"))
+        user1.save()
+
+        user2 = User.objects.create_user(username="test2")
+        user2.save()
+
+        doc = Document.objects.create(
+            title="test",
+            mime_type="application/pdf",
+            content="this is a document which will be protected",
+            owner=user2,
+        )
+
+        self.client.force_authenticate(user1)
+
+        create_resp = self.client.post(
+            "/api/share_links/",
+            data={
+                "document": doc.pk,
+                "file_version": "original",
+            },
+            format="json",
+        )
+        self.assertEqual(create_resp.status_code, status.HTTP_403_FORBIDDEN)
+
+        assign_perm("view_document", user1, doc)
+
+        create_resp = self.client.post(
+            "/api/share_links/",
+            data={
+                "document": doc.pk,
+                "file_version": "original",
+            },
+            format="json",
+        )
+        self.assertEqual(create_resp.status_code, status.HTTP_201_CREATED)
+        self.assertEqual(create_resp.data["document"], doc.pk)
+
     def test_next_asn(self):
         """
         GIVEN: