mirror of
https://gitlab.crans.org/bde/nk20
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163 lines
5.9 KiB
Python
163 lines
5.9 KiB
Python
# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
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# SPDX-License-Identifier: GPL-3.0-or-later
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from django.contrib.auth.backends import ModelBackend
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from django.contrib.auth.models import User, AnonymousUser
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from django.contrib.contenttypes.models import ContentType
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from django.db.models import Q, F
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from django.utils import timezone
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from note.models import Note, NoteUser, NoteClub, NoteSpecial
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from note_kfet.middlewares import get_current_session
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from member.models import Membership, Club
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from .decorators import memoize
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from .models import Permission
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class PermissionBackend(ModelBackend):
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"""
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Manage permissions of users
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"""
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supports_object_permissions = True
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supports_anonymous_user = False
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supports_inactive_user = False
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@staticmethod
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@memoize
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def get_raw_permissions(user, t):
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"""
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Query permissions of a certain type for a user, then memoize it.
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:param user: The owner of the permissions
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:param t: The type of the permissions: view, change, add or delete
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:return: The queryset of the permissions of the user (memoized) grouped by clubs
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"""
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if isinstance(user, AnonymousUser):
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# Unauthenticated users have no permissions
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return Permission.objects.none()
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memberships = Membership.objects.filter(user=user).all()
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perms = []
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for membership in memberships:
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for role in membership.roles.all():
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for perm in role.permissions.filter(type=t, mask__rank__lte=get_current_session().get("permission_mask", -1)).all():
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if not perm.permanent:
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if membership.date_start > timezone.now().date() or membership.date_end < timezone.now().date():
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continue
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perm.membership = membership
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perms.append(perm)
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return perms
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@staticmethod
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def permissions(user, model, type):
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"""
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List all permissions of the given user that applies to a given model and a give type
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:param user: The owner of the permissions
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:param model: The model that the permissions shoud apply
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:param type: The type of the permissions: view, change, add or delete
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:return: A generator of the requested permissions
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"""
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for permission in PermissionBackend.get_raw_permissions(user, type):
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if not isinstance(model.model_class()(), permission.model.model_class()) or not permission.membership:
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continue
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membership = permission.membership
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club = membership.club
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permission = permission.about(
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user=user,
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club=club,
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membership=membership,
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User=User,
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Club=Club,
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Membership=Membership,
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Note=Note,
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NoteUser=NoteUser,
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NoteClub=NoteClub,
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NoteSpecial=NoteSpecial,
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F=F,
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Q=Q,
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now=timezone.now(),
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today=timezone.now().date(),
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)
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yield permission
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@staticmethod
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@memoize
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def filter_queryset(user, model, t, field=None):
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"""
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Filter a queryset by considering the permissions of a given user.
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:param user: The owner of the permissions that are fetched
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:param model: The concerned model of the queryset
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:param t: The type of modification (view, add, change, delete)
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:param field: The field of the model to test, if concerned
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:return: A query that corresponds to the filter to give to a queryset
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"""
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if user is None or isinstance(user, AnonymousUser):
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# Anonymous users can't do anything
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return Q(pk=-1)
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if user.is_superuser and get_current_session().get("permission_mask", -1) >= 42:
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# Superusers have all rights
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return Q()
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if not isinstance(model, ContentType):
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model = ContentType.objects.get_for_model(model)
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# Never satisfied
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query = Q(pk=-1)
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perms = PermissionBackend.permissions(user, model, t)
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for perm in perms:
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if perm.field and field != perm.field:
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continue
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if perm.type != t or perm.model != model:
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continue
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perm.update_query()
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query = query | perm.query
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return query
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@staticmethod
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@memoize
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def check_perm(user_obj, perm, obj=None):
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"""
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Check is the given user has the permission over a given object.
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The result is then memoized.
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Exception: for add permissions, since the object is not hashable since it doesn't have any
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primary key, the result is not memoized. Moreover, the right could change
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(e.g. for a transaction, the balance of the user could change)
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"""
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if user_obj is None or isinstance(user_obj, AnonymousUser):
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return False
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sess = get_current_session()
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if sess is not None and sess.session_key is None:
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return False
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if user_obj.is_superuser and sess.get("permission_mask", -1) >= 42:
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return True
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if obj is None:
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return True
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perm = perm.split('.')[-1].split('_', 2)
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perm_type = perm[0]
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perm_field = perm[2] if len(perm) == 3 else None
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ct = ContentType.objects.get_for_model(obj)
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if any(permission.applies(obj, perm_type, perm_field)
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for permission in PermissionBackend.permissions(user_obj, ct, perm_type)):
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return True
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return False
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def has_perm(self, user_obj, perm, obj=None):
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return PermissionBackend.check_perm(user_obj, perm, obj)
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def has_module_perms(self, user_obj, app_label):
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return False
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def get_all_permissions(self, user_obj, obj=None):
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ct = ContentType.objects.get_for_model(obj)
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return list(self.permissions(user_obj, ct, "view"))
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