ipn/{ipnlocal,ipnserver}: remove redundant (*LocalBackend).ResetForClientDisconnect

In this commit, we add a failing test to verify that ipn/ipnserver.Server correctly
sets and unsets the current user when two different users connect sequentially
(A connects, A disconnects, B connects, B disconnects).

We then fix the test by updating (*ipn/ipnserver.Server).addActiveHTTPRequest
to avoid calling (*LocalBackend).ResetForClientDisconnect again after a new user
has connected and been set as the current user with (*LocalBackend).SetCurrentUser().

Since ipn/ipnserver.Server does not allow simultaneous connections from different
Windows users and relies on the LocalBackend's current user, and since we already
reset the LocalBackend's state by calling ResetForClientDisconnect when the last
active request completes (indicating the server is idle and can accept connections
from any Windows user), it is unnecessary to track the last connected user on the
ipnserver.Server side or call ResetForClientDisconnect again when the user changes.

Additionally, the second call to ResetForClientDisconnect occurs after the new user
has been set as the current user, resetting the correct state for the new user
instead of the old state of the now-disconnected user, causing issues.

Updates tailscale/corp#25804

Signed-off-by: Nick Khyl <nickk@tailscale.com>
This commit is contained in:
Nick Khyl
2025-01-13 17:42:12 -06:00
committed by Nick Khyl
parent c3c4c96489
commit f33f5f99c0
3 changed files with 42 additions and 36 deletions

View File

@@ -3620,7 +3620,7 @@ func (b *LocalBackend) shouldUploadServices() bool {
}
// SetCurrentUser is used to implement support for multi-user systems (only
// Windows 2022-11-25). On such systems, the uid is used to determine which
// Windows 2022-11-25). On such systems, the actor is used to determine which
// user's state should be used. The current user is maintained by active
// connections open to the backend.
//
@@ -3634,11 +3634,8 @@ func (b *LocalBackend) shouldUploadServices() bool {
// unattended mode. The user must disable unattended mode before the user can be
// changed.
//
// On non-multi-user systems, the user should be set to nil.
//
// SetCurrentUser returns the ipn.WindowsUserID associated with the user
// when successful.
func (b *LocalBackend) SetCurrentUser(actor ipnauth.Actor) (ipn.WindowsUserID, error) {
// On non-multi-user systems, the actor should be set to nil.
func (b *LocalBackend) SetCurrentUser(actor ipnauth.Actor) {
var uid ipn.WindowsUserID
if actor != nil {
uid = actor.UserID()
@@ -3647,16 +3644,17 @@ func (b *LocalBackend) SetCurrentUser(actor ipnauth.Actor) (ipn.WindowsUserID, e
unlock := b.lockAndGetUnlock()
defer unlock()
if b.pm.CurrentUserID() == uid {
return uid, nil
if actor != b.currentUser {
if c, ok := b.currentUser.(ipnauth.ActorCloser); ok {
c.Close()
}
b.currentUser = actor
}
b.pm.SetCurrentUserID(uid)
if c, ok := b.currentUser.(ipnauth.ActorCloser); ok {
c.Close()
if b.pm.CurrentUserID() != uid {
b.pm.SetCurrentUserID(uid)
b.resetForProfileChangeLockedOnEntry(unlock)
}
b.currentUser = actor
b.resetForProfileChangeLockedOnEntry(unlock)
return uid, nil
}
// CurrentUserForTest returns the current user and the associated WindowsUserID.