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authentik/authentik/flows/models.py

307 lines
10 KiB
Python

"""Flow models"""
from base64 import b64decode, b64encode
from pickle import dumps, loads # nosec
from typing import TYPE_CHECKING, Optional
from uuid import uuid4
from django.db import models
from django.utils.translation import gettext_lazy as _
from model_utils.managers import InheritanceManager
from rest_framework.serializers import BaseSerializer
from structlog.stdlib import get_logger
from authentik.core.models import Token
from authentik.core.types import UserSettingSerializer
from authentik.flows.challenge import FlowLayout
from authentik.lib.models import InheritanceForeignKey, SerializerModel
from authentik.lib.utils.reflection import class_to_path
from authentik.policies.models import PolicyBindingModel
if TYPE_CHECKING:
from authentik.flows.planner import FlowPlan
from authentik.flows.stage import StageView
LOGGER = get_logger()
class FlowAuthenticationRequirement(models.TextChoices):
"""Required level of authentication and authorization to access a flow"""
NONE = "none"
REQUIRE_AUTHENTICATED = "require_authenticated"
REQUIRE_UNAUTHENTICATED = "require_unauthenticated"
REQUIRE_SUPERUSER = "require_superuser"
class NotConfiguredAction(models.TextChoices):
"""Decides how the FlowExecutor should proceed when a stage isn't configured"""
SKIP = "skip"
DENY = "deny"
CONFIGURE = "configure"
class InvalidResponseAction(models.TextChoices):
"""Configure how the flow executor should handle invalid responses to challenges"""
RETRY = "retry"
RESTART = "restart"
RESTART_WITH_CONTEXT = "restart_with_context"
class FlowDeniedAction(models.TextChoices):
"""Configure what response is given to denied flow executions"""
MESSAGE_CONTINUE = "message_continue"
MESSAGE = "message"
CONTINUE = "continue"
class FlowDesignation(models.TextChoices):
"""Designation of what a Flow should be used for. At a later point, this
should be replaced by a database entry."""
AUTHENTICATION = "authentication"
AUTHORIZATION = "authorization"
INVALIDATION = "invalidation"
ENROLLMENT = "enrollment"
UNRENOLLMENT = "unenrollment"
RECOVERY = "recovery"
STAGE_CONFIGURATION = "stage_configuration"
class Stage(SerializerModel):
"""Stage is an instance of a component used in a flow. This can verify the user,
enroll the user or offer a way of recovery"""
stage_uuid = models.UUIDField(primary_key=True, editable=False, default=uuid4)
name = models.TextField(unique=True)
objects = InheritanceManager()
@property
def type(self) -> type["StageView"]:
"""Return StageView class that implements logic for this stage"""
# This is a bit of a workaround, since we can't set class methods with setattr
if hasattr(self, "__in_memory_type"):
return getattr(self, "__in_memory_type")
raise NotImplementedError
@property
def component(self) -> str:
"""Return component used to edit this object"""
raise NotImplementedError
def ui_user_settings(self) -> Optional[UserSettingSerializer]:
"""Entrypoint to integrate with User settings. Can either return None if no
user settings are available, or a challenge."""
return None
def __str__(self):
if hasattr(self, "__in_memory_type"):
return f"In-memory Stage {getattr(self, '__in_memory_type')}"
return f"Stage {self.name}"
def in_memory_stage(view: type["StageView"], **kwargs) -> Stage:
"""Creates an in-memory stage instance, based on a `view` as view."""
stage = Stage()
# Because we can't pickle a locally generated function,
# we set the view as a separate property and reference a generic function
# that returns that member
setattr(stage, "__in_memory_type", view)
setattr(stage, "name", _("Dynamic In-memory stage: %(doc)s" % {"doc": view.__doc__}))
setattr(stage._meta, "verbose_name", class_to_path(view))
for key, value in kwargs.items():
setattr(stage, key, value)
return stage
class Flow(SerializerModel, PolicyBindingModel):
"""Flow describes how a series of Stages should be executed to authenticate/enroll/recover
a user. Additionally, policies can be applied, to specify which users
have access to this flow."""
flow_uuid = models.UUIDField(primary_key=True, editable=False, default=uuid4)
name = models.TextField()
slug = models.SlugField(unique=True, help_text=_("Visible in the URL."))
title = models.TextField(help_text=_("Shown as the Title in Flow pages."))
layout = models.TextField(default=FlowLayout.STACKED, choices=FlowLayout.choices)
designation = models.CharField(
max_length=100,
choices=FlowDesignation.choices,
help_text=_(
"Decides what this Flow is used for. For example, the Authentication flow "
"is redirect to when an un-authenticated user visits authentik."
),
)
background = models.FileField(
upload_to="flow-backgrounds/",
default=None,
null=True,
help_text=_("Background shown during execution"),
max_length=500,
)
compatibility_mode = models.BooleanField(
default=False,
help_text=_(
"Enable compatibility mode, increases compatibility with "
"password managers on mobile devices."
),
)
denied_action = models.TextField(
choices=FlowDeniedAction.choices,
default=FlowDeniedAction.MESSAGE_CONTINUE,
help_text=_("Configure what should happen when a flow denies access to a user."),
)
authentication = models.TextField(
choices=FlowAuthenticationRequirement.choices,
default=FlowAuthenticationRequirement.NONE,
help_text=_("Required level of authentication and authorization to access a flow."),
)
@property
def background_url(self) -> str:
"""Get the URL to the background image. If the name is /static or starts with http
it is returned as-is"""
if not self.background:
return "/static/dist/assets/images/flow_background.jpg"
if self.background.name.startswith("http") or self.background.name.startswith("/static"):
return self.background.name
return self.background.url
stages = models.ManyToManyField(Stage, through="FlowStageBinding", blank=True)
@property
def serializer(self) -> type[BaseSerializer]:
from authentik.flows.api.flows import FlowSerializer
return FlowSerializer
def __str__(self) -> str:
return f"Flow {self.name} ({self.slug})"
class Meta:
verbose_name = _("Flow")
verbose_name_plural = _("Flows")
permissions = [
("export_flow", "Can export a Flow"),
("view_flow_cache", "View Flow's cache metrics"),
("clear_flow_cache", "Clear Flow's cache metrics"),
]
class FlowStageBinding(SerializerModel, PolicyBindingModel):
"""Relationship between Flow and Stage. Order is required and unique for
each flow-stage Binding. Additionally, policies can be specified, which determine if
this Binding applies to the current user"""
fsb_uuid = models.UUIDField(primary_key=True, editable=False, default=uuid4)
target = models.ForeignKey("Flow", on_delete=models.CASCADE)
stage = InheritanceForeignKey(Stage, on_delete=models.CASCADE)
evaluate_on_plan = models.BooleanField(
default=False,
help_text=_("Evaluate policies during the Flow planning process."),
)
re_evaluate_policies = models.BooleanField(
default=True,
help_text=_("Evaluate policies when the Stage is present to the user."),
)
invalid_response_action = models.TextField(
choices=InvalidResponseAction.choices,
default=InvalidResponseAction.RETRY,
help_text=_(
"Configure how the flow executor should handle an invalid response to a "
"challenge. RETRY returns the error message and a similar challenge to the "
"executor. RESTART restarts the flow from the beginning, and RESTART_WITH_CONTEXT "
"restarts the flow while keeping the current context."
),
)
order = models.IntegerField()
objects = InheritanceManager()
@property
def serializer(self) -> type[BaseSerializer]:
from authentik.flows.api.bindings import FlowStageBindingSerializer
return FlowStageBindingSerializer
def __str__(self) -> str:
return f"Flow-stage binding #{self.order} to {self.target_id}"
class Meta:
ordering = ["target", "order"]
verbose_name = _("Flow Stage Binding")
verbose_name_plural = _("Flow Stage Bindings")
unique_together = (("target", "stage", "order"),)
class ConfigurableStage(models.Model):
"""Abstract base class for a Stage that can be configured by the enduser.
The stage should create a default flow with the configure_stage designation during
migration."""
configure_flow = models.ForeignKey(
Flow,
on_delete=models.SET_NULL,
null=True,
blank=True,
help_text=_(
"Flow used by an authenticated user to configure this Stage. "
"If empty, user will not be able to configure this stage."
),
)
class Meta:
abstract = True
class FriendlyNamedStage(models.Model):
"""Abstract base class for a Stage that can have a user friendly name configured."""
friendly_name = models.TextField(null=True)
class Meta:
abstract = True
class FlowToken(Token):
"""Subclass of a standard Token, stores the currently active flow plan upon creation.
Can be used to later resume a flow."""
flow = models.ForeignKey(Flow, on_delete=models.CASCADE)
_plan = models.TextField()
@staticmethod
def pickle(plan) -> str:
"""Pickle into string"""
data = dumps(plan)
return b64encode(data).decode()
@property
def plan(self) -> "FlowPlan":
"""Load Flow plan from pickled version"""
return loads(b64decode(self._plan.encode())) # nosec
def __str__(self) -> str:
return f"Flow Token {super().__str__()}"
class Meta:
verbose_name = _("Flow Token")
verbose_name_plural = _("Flow Tokens")