llama-stack-mirror/llama_stack/distribution/request_headers.py
grs 7c1998db25
feat: fine grained access control policy (#2264)
This allows a set of rules to be defined for determining access to
resources. The rules are (loosely) based on the cedar policy format.

A rule defines a list of action either to permit or to forbid. It may
specify a principal or a resource that must match for the rule to take
effect. It may also specify a condition, either a 'when' or an 'unless',
with additional constraints as to where the rule applies.

A list of rules is held for each type to be protected and tried in order
to find a match. If a match is found, the request is permitted or
forbidden depening on the type of rule. If no match is found, the
request is denied. If no rules are specified for a given type, a rule
that allows any action as long as the resource attributes match the user
attributes is added (i.e. the previous behaviour is the default.

Some examples in yaml:

```
    model:
    - permit:
      principal: user-1
      actions: [create, read, delete]
      comment: user-1 has full access to all models
    - permit:
      principal: user-2
      actions: [read]
      resource: model-1
      comment: user-2 has read access to model-1 only
    - permit:
      actions: [read]
      when:
        user_in: resource.namespaces
      comment: any user has read access to models with matching attributes
    vector_db:
    - forbid:
      actions: [create, read, delete]
      unless:
        user_in: role::admin
      comment: only user with admin role can use vector_db resources
```

---------

Signed-off-by: Gordon Sim <gsim@redhat.com>
2025-06-03 14:51:12 -07:00

103 lines
3.2 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.
import contextvars
import json
import logging
from contextlib import AbstractContextManager
from typing import Any
from llama_stack.distribution.datatypes import User
from .utils.dynamic import instantiate_class_type
log = logging.getLogger(__name__)
# Context variable for request provider data and auth attributes
PROVIDER_DATA_VAR = contextvars.ContextVar("provider_data", default=None)
class RequestProviderDataContext(AbstractContextManager):
"""Context manager for request provider data"""
def __init__(self, provider_data: dict[str, Any] | None = None, user: User | None = None):
self.provider_data = provider_data or {}
if user:
self.provider_data["__authenticated_user"] = user
self.token = None
def __enter__(self):
# Save the current value and set the new one
self.token = PROVIDER_DATA_VAR.set(self.provider_data)
return self
def __exit__(self, exc_type, exc_val, exc_tb):
# Restore the previous value
if self.token is not None:
PROVIDER_DATA_VAR.reset(self.token)
class NeedsRequestProviderData:
def get_request_provider_data(self) -> Any:
spec = self.__provider_spec__
if not spec:
raise ValueError(f"Provider spec not set on {self.__class__}")
provider_type = spec.provider_type
validator_class = spec.provider_data_validator
if not validator_class:
raise ValueError(f"Provider {provider_type} does not have a validator")
val = PROVIDER_DATA_VAR.get()
if not val:
return None
validator = instantiate_class_type(validator_class)
try:
provider_data = validator(**val)
return provider_data
except Exception as e:
log.error(f"Error parsing provider data: {e}")
return None
def parse_request_provider_data(headers: dict[str, str]) -> dict[str, Any] | None:
"""Parse provider data from request headers"""
keys = [
"X-LlamaStack-Provider-Data",
"x-llamastack-provider-data",
]
val = None
for key in keys:
val = headers.get(key, None)
if val:
break
if not val:
return None
try:
return json.loads(val)
except json.JSONDecodeError:
log.error("Provider data not encoded as a JSON object!")
return None
def request_provider_data_context(
headers: dict[str, str], auth_attributes: dict[str, list[str]] | None = None
) -> AbstractContextManager:
"""Context manager that sets request provider data from headers and auth attributes for the duration of the context"""
provider_data = parse_request_provider_data(headers)
return RequestProviderDataContext(provider_data, auth_attributes)
def get_authenticated_user() -> User | None:
"""Helper to retrieve auth attributes from the provider data context"""
provider_data = PROVIDER_DATA_VAR.get()
if not provider_data:
return None
return provider_data.get("__authenticated_user")