We never implemented the peercred package on OpenBSD (and I just tried
again and failed), but we've always documented that the creds pointer
can be nil for operating systems where we can't map the unix socket
back to its UID. On those platforms, we set the default unix socket
permissions such that only the admin can open it anyway and we don't
have a read-only vs read-write distinction. OpenBSD was always in that
camp, where any access to Tailscale's unix socket meant full access.
But during some refactoring, we broke OpenBSD in that we started
assuming during one logging path (during login) that Creds was non-nil
when looking up an ipnauth.Actor's username, which wasn't relevant (it
was called from a function "maybeUsernameOf" anyway, which threw away
errors).
Verified on an OpenBSD VM. We don't have any OpenBSD integration tests yet.
Fixes#17209
Updates #17221
Change-Id: I473c5903dfaa645694bcc75e7f5d484f3dd6044d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
We add the ClientID() method to the ipnauth.Actor interface and updated ipnserver.actor to implement it.
This method returns a unique ID of the connected client if the actor represents one. It helps link a series
of interactions initiated by the client, such as when a notification needs to be sent back to a specific session,
rather than all active sessions, in response to a certain request.
We also add LocalBackend.WatchNotificationsAs and LocalBackend.StartLoginInteractiveAs methods,
which are like WatchNotifications and StartLoginInteractive but accept an additional parameter
specifying an ipnauth.Actor who initiates the operation. We store these actor identities in
watchSession.owner and LocalBackend.authActor, respectively,and implement LocalBackend.sendTo
and related helper methods to enable sending notifications to watchSessions associated with actors
(or, more broadly, identifiable recipients).
We then use the above to change who receives the BrowseToURL notifications:
- For user-initiated, interactive logins, the notification is delivered only to the user who initiated the
process. If the initiating actor represents a specific connected client, the URL notification is sent back
to the same LocalAPI client that called StartLoginInteractive. Otherwise, the notification is sent to all
clients connected as that user.
Currently, we only differentiate between users on Windows, as it is inherently a multi-user OS.
- In all other cases (e.g., node key expiration), we send the notification to all connected users.
Updates tailscale/corp#18342
Signed-off-by: Nick Khyl <nickk@tailscale.com>
On Windows, the idiomatic way to check access on a named pipe is for
the server to impersonate the client on its current OS thread, perform
access checks using the client's access token, and then revert the OS
thread's access token back to its true self.
The access token is a better representation of the client's rights than just
a username/userid check, as it represents the client's effective rights
at connection time, which might differ from their normal rights.
This patch updates safesocket to do the aforementioned impersonation,
extract the token handle, and then revert the impersonation. We retain
the token handle for the remaining duration of the connection (the token
continues to be valid even after we have reverted back to self).
Since the token is a property of the connection, I changed ipnauth to wrap
the concrete net.Conn to include the token. I then plumbed that change
through ipnlocal, ipnserver, and localapi as necessary.
I also added a PermitLocalAdmin flag to the localapi Handler which I intend
to use for controlling access to a few new localapi endpoints intended
for configuring auto-update.
Updates https://github.com/tailscale/tailscale/issues/755
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This updates all source files to use a new standard header for copyright
and license declaration. Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.
This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.
Updates #6865
Signed-off-by: Will Norris <will@tailscale.com>
Brad Fitzpatrick
Nick Khyl
Aaron Klotz
Will Norris
Maisem Ali