This updates the syspolicy package to support multiple policy sources in the
three policy scopes: user, profile, and device, and provides a merged resultant
policy. A policy source is a syspolicy/source.Store that has a name and provides
access to policy settings for a given scope. It can be registered with
syspolicy/rsop.RegisterStore. Policy sources and policy stores can be either
platform-specific or platform-agnostic. On Windows, we have the Registry-based,
platform-specific policy store implemented as
syspolicy/source.PlatformPolicyStore. This store provides access to the Group
Policy and MDM policy settings stored in the Registry. On other platforms, we
currently provide a wrapper that converts a syspolicy.Handler into a
syspolicy/source.Store. However, we should update them in follow-up PRs. An
example of a platform-agnostic policy store would be a policy deployed from the
control, a local policy config file, or even environment variables.
We maintain the current, most recent version of the resultant policy for each
scope in an rsop.Policy. This is done by reading and merging the policy settings
from the registered stores the first time the resultant policy is requested,
then re-reading and re-merging them if a store implements the source.Changeable
interface and reports a policy change. Policy change notifications are debounced
to avoid re-reading policy settings multiple times if there are several changes
within a short period. The rsop.Policy can notify clients if the resultant
policy has changed. However, we do not currently expose this via the syspolicy
package and plan to do so differently along with a struct-based policy hierarchy
in the next PR.
To facilitate this, all policy settings should be registered with the
setting.Register function. The syspolicy package does this automatically for all
policy settings defined in policy_keys.go.
The new functionality is available through the existing syspolicy.Read* set of
functions. However, we plan to expose it via a struct-based policy hierarchy,
along with policy change notifications that other subsystems can use, in the
next PR. We also plan to send the resultant policy back from tailscaled to the
clients via the LocalAPI.
This is primarily a foundational PR to facilitate future changes, but the
immediate observable changes on Windows include:
- The service will use the current policy setting values instead of those read
at OS boot time.
- The GUI has access to policy settings configured on a per-user basis.
On Android:
- We now report policy setting usage via clientmetrics.
Updates #12687
Signed-off-by: Nick Khyl <nickk@tailscale.com>
Fixestailscale/corp#19459
This PR adds the ability for users of the syspolicy handler to read string arrays from the MDM solution configured on the system.
Signed-off-by: Andrea Gottardo <andrea@gottardo.me>
Adds policy keys ExitNodeID and ExitNodeIP.
Uses the policy keys to determine the exit node in preferences.
Fixestailscale/corp#15683
Signed-off-by: Claire Wang <claire@tailscale.com>
