Update dependencies

vendor/tailscale.com/ipn/ipnauth/policy.go

@@ -0,0 +1,74 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package ipnauth
+
+import (
+	"errors"
+	"fmt"
+
+	"tailscale.com/client/tailscale/apitype"
+	"tailscale.com/ipn"
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/syspolicy"
+)
+
+type actorWithPolicyChecks struct{ Actor }
+
+// WithPolicyChecks returns an [Actor] that wraps the given actor and
+// performs additional policy checks on top of the access checks
+// implemented by the wrapped actor.
+func WithPolicyChecks(actor Actor) Actor {
+	// TODO(nickkhyl): We should probably exclude the Windows Local System
+	// account from policy checks as well.
+	switch actor.(type) {
+	case unrestricted:
+		return actor
+	default:
+		return &actorWithPolicyChecks{Actor: actor}
+	}
+}
+
+// CheckProfileAccess implements [Actor].
+func (a actorWithPolicyChecks) CheckProfileAccess(profile ipn.LoginProfileView, requestedAccess ProfileAccess, auditLogger AuditLogFunc) error {
+	if err := a.Actor.CheckProfileAccess(profile, requestedAccess, auditLogger); err != nil {
+		return err
+	}
+	requestReason := apitype.RequestReasonKey.Value(a.Context())
+	return CheckDisconnectPolicy(a.Actor, profile, requestReason, auditLogger)
+}
+
+// CheckDisconnectPolicy checks if the policy allows the specified actor to disconnect
+// Tailscale with the given optional reason. It returns nil if the operation is allowed,
+// or an error if it is not. If auditLogger is non-nil, it is called to log the action
+// when required by the policy.
+//
+// Note: this function only checks the policy and does not check whether the actor has
+// the necessary access rights to the device or profile. It is intended to be used by
+// [Actor] implementations on platforms where [syspolicy] is supported.
+//
+// TODO(nickkhyl): unexport it when we move [ipn.Actor] implementations from [ipnserver]
+// and corp to this package.
+func CheckDisconnectPolicy(actor Actor, profile ipn.LoginProfileView, reason string, auditFn AuditLogFunc) error {
+	if alwaysOn, _ := syspolicy.GetBoolean(syspolicy.AlwaysOn, false); !alwaysOn {
+		return nil
+	}
+	if allowWithReason, _ := syspolicy.GetBoolean(syspolicy.AlwaysOnOverrideWithReason, false); !allowWithReason {
+		return errors.New("disconnect not allowed: always-on mode is enabled")
+	}
+	if reason == "" {
+		return errors.New("disconnect not allowed: reason required")
+	}
+	if auditFn != nil {
+		var details string
+		if username, _ := actor.Username(); username != "" { // best-effort; we don't have it on all platforms
+			details = fmt.Sprintf("%q is being disconnected by %q: %v", profile.Name(), username, reason)
+		} else {
+			details = fmt.Sprintf("%q is being disconnected: %v", profile.Name(), reason)
+		}
+		if err := auditFn(tailcfg.AuditNodeDisconnect, details); err != nil {
+			return err
+		}
+	}
+	return nil
+}