add SSO session extend flow

Adds an end-to-end SSO session-extension feature: the management server
publishes per-peer session deadlines on every Login/Sync, a new
ExtendAuthSession RPC refreshes the deadline using a fresh JWT without
tearing down the tunnel, and the daemon tracks the deadline locally so
the UI can fire a T-10min warning toast with an interactive "Extend now"
action.

client/internal/auth/auth.go

@@ -3,6 +3,7 @@ package auth
 import (
 	"context"
 	"net/url"
+	"strings"
 	"sync"
 	"time"
 
@@ -21,6 +22,25 @@ import (
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
 )
 
+// peerLoginExpiredMsg is the exact phrase the management server returns
+// when a previously SSO-enrolled peer's login has expired. Sourced from
+// shared/management/status/error.go (NewPeerLoginExpiredError). Matched
+// by substring so a future server-side rewording that keeps the phrase
+// still triggers the friendly fallback in Login().
+const peerLoginExpiredMsg = "peer login has expired"
+
+// errSetupKeyOnSSOExpiredPeer replaces the raw management error when the
+// user runs `netbird login -k <setup-key>` against a peer that was
+// originally enrolled via SSO. Wrapped in a PermissionDenied gRPC status
+// so callers' existing isPermissionDenied / isAuthError checks still
+// classify it correctly (early-exit from retry backoff, StatusNeedsLogin
+// in the server state machine).
+var errSetupKeyOnSSOExpiredPeer = status.Error(
+	codes.PermissionDenied,
+	"this peer was originally enrolled via SSO and its session has expired. "+
+		"Setup keys can only enrol new peers — run `netbird up` (interactive SSO) to re-login.",
+)
+
 // Auth manages authentication operations with the management server
 // It maintains a long-lived connection and automatically handles reconnection with backoff
 type Auth struct {
@@ -184,6 +204,15 @@ func (a *Auth) Login(ctx context.Context, setupKey string, jwtToken string) (err
 			log.Debugf("peer registration required")
 			_, err = a.registerPeer(client, ctx, setupKey, jwtToken, pubSSHKey)
 			if err != nil {
+				// The peer pub-key is already on file with the management
+				// server (originally enrolled via SSO) and the session has
+				// expired. The setup-key path can only enrol new peers, so
+				// retrying with -k will keep failing. Replace the raw mgm
+				// message with an actionable hint that tells the user to
+				// re-authenticate via SSO instead.
+				if setupKey != "" && jwtToken == "" && isPeerLoginExpired(err) {
+					err = errSetupKeyOnSSOExpiredPeer
+				}
 				isAuthError = isPermissionDenied(err)
 				return err
 			}
@@ -474,3 +503,16 @@ func isLoginNeeded(err error) bool {
 func isRegistrationNeeded(err error) bool {
 	return isPermissionDenied(err)
 }
+
+// isPeerLoginExpired reports whether err is the management server's
+// "peer login has expired" PermissionDenied response. Used by Login to
+// detect the case where the caller passed a setup-key but the peer is
+// actually an SSO-enrolled record whose session needs refreshing — the
+// setup-key path cannot help there.
+func isPeerLoginExpired(err error) bool {
+	if !isPermissionDenied(err) {
+		return false
+	}
+	s, _ := status.FromError(err)
+	return strings.Contains(s.Message(), peerLoginExpiredMsg)
+}

client/internal/auth/auth_test.go

@@ -0,0 +1,80 @@
+package auth
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+func TestIsPeerLoginExpired(t *testing.T) {
+	cases := []struct {
+		name string
+		err  error
+		want bool
+	}{
+		{
+			name: "nil",
+			err:  nil,
+			want: false,
+		},
+		{
+			name: "plain error (not a gRPC status)",
+			err:  errors.New("network read: connection reset"),
+			want: false,
+		},
+		{
+			name: "PermissionDenied with different message",
+			err:  status.Error(codes.PermissionDenied, "user is blocked"),
+			want: false,
+		},
+		{
+			name: "Unauthenticated with the expected phrase",
+			// Wrong status code — must still return false.
+			err:  status.Error(codes.Unauthenticated, "peer login has expired, please log in once more"),
+			want: false,
+		},
+		{
+			name: "exact server message",
+			err:  status.Error(codes.PermissionDenied, "peer login has expired, please log in once more"),
+			want: true,
+		},
+		{
+			name: "phrase as substring",
+			// Future-proofing: if mgm reworords but keeps the phrase,
+			// the friendly fallback must still kick in.
+			err:  status.Error(codes.PermissionDenied, "session refused: peer login has expired (account=foo)"),
+			want: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := isPeerLoginExpired(tc.err); got != tc.want {
+				t.Fatalf("isPeerLoginExpired(%v) = %v, want %v", tc.err, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestErrSetupKeyOnSSOExpiredPeer(t *testing.T) {
+	// Sentinel must surface as PermissionDenied so the upstream
+	// isPermissionDenied / isAuthError checks classify it correctly
+	// (short-circuit retry backoff, set StatusNeedsLogin).
+	if !isPermissionDenied(errSetupKeyOnSSOExpiredPeer) {
+		t.Fatalf("errSetupKeyOnSSOExpiredPeer must be a PermissionDenied gRPC error")
+	}
+
+	// Message must actually mention SSO and `netbird up` so it is
+	// actionable for the end user. Loose substring checks keep the
+	// test resilient to copy edits.
+	s, _ := status.FromError(errSetupKeyOnSSOExpiredPeer)
+	msg := strings.ToLower(s.Message())
+	for _, want := range []string{"sso", "netbird up"} {
+		if !strings.Contains(msg, want) {
+			t.Errorf("sentinel message should contain %q, got %q", want, s.Message())
+		}
+	}
+}

client/internal/auth/pending_flow.go

@@ -0,0 +1,89 @@
+package auth
+
+import (
+	"context"
+	"sync"
+	"time"
+)
+
+// PendingFlow stores an in-progress OAuth flow between the RPC that
+// initiates it (returns the verification URI to the UI) and the RPC
+// that waits for the user to complete it. The flow handle, the
+// device-code info, and the absolute expiry are kept together so the
+// waiting RPC can validate the device code and reuse the same flow.
+//
+// PendingFlow is safe for concurrent use; callers must not access the
+// stored fields directly.
+type PendingFlow struct {
+	mu         sync.Mutex
+	flow       OAuthFlow
+	info       AuthFlowInfo
+	expiresAt  time.Time
+	waitCancel context.CancelFunc
+}
+
+// NewPendingFlow returns an empty PendingFlow ready to be populated by Set.
+func NewPendingFlow() *PendingFlow {
+	return &PendingFlow{}
+}
+
+// Set stores the flow and its authorization info, computing the absolute
+// expiry from info.ExpiresIn (seconds, as returned by the IdP).
+func (p *PendingFlow) Set(flow OAuthFlow, info AuthFlowInfo) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.flow = flow
+	p.info = info
+	p.expiresAt = time.Now().Add(time.Duration(info.ExpiresIn) * time.Second)
+}
+
+// Get returns the stored flow, info, and whether a flow is currently
+// pending. Returns (nil, zero, false) after Clear or before Set.
+func (p *PendingFlow) Get() (OAuthFlow, AuthFlowInfo, bool) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.flow == nil {
+		return nil, AuthFlowInfo{}, false
+	}
+	return p.flow, p.info, true
+}
+
+// ExpiresAt returns the absolute expiry of the pending flow. Returns
+// the zero time when no flow is pending.
+func (p *PendingFlow) ExpiresAt() time.Time {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return p.expiresAt
+}
+
+// SetWaitCancel records the cancel function for the goroutine currently
+// blocked in WaitToken so a new RequestAuth can preempt it.
+func (p *PendingFlow) SetWaitCancel(cancel context.CancelFunc) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.waitCancel = cancel
+}
+
+// CancelWait invokes and clears the stored wait-cancel, if any. Safe to
+// call when no wait is in progress.
+func (p *PendingFlow) CancelWait() {
+	p.mu.Lock()
+	cancel := p.waitCancel
+	p.waitCancel = nil
+	p.mu.Unlock()
+	if cancel != nil {
+		cancel()
+	}
+}
+
+// Clear resets the pending flow to empty. Any stored wait-cancel is
+// dropped without being invoked — call CancelWait first if the waiting
+// goroutine must be stopped.
+func (p *PendingFlow) Clear() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.flow = nil
+	p.info = AuthFlowInfo{}
+	p.expiresAt = time.Time{}
+	p.waitCancel = nil
+}

client/internal/auth/sessionwatch/event.go

@@ -0,0 +1,74 @@
+package sessionwatch
+
+import (
+	"strconv"
+	"time"
+)
+
+// internal event kinds are no longer exposed: the watcher drives the Sink
+// directly (NotifyStateChange on deadline change/clear, PublishEvent at
+// each warning lead). Tests use a mock Sink to observe what the watcher
+// emits.
+
+// Metadata keys attached by the daemon to session-warning SystemEvents.
+// The UI tray reads these to build a locale-aware notification without
+// relying on the daemon's locale-less UserMessage string, and to
+// disambiguate the T-WarningLead notification from the T-FinalWarningLead
+// fallback that auto-opens the SessionAboutToExpire dialog.
+const (
+	// MetaSessionWarning is set to "true" on both warning events (T-10 and
+	// T-2) so the UI can detect a session-warning SystemEvent without
+	// matching on the message text. Use MetaSessionFinal to distinguish
+	// the two.
+	MetaSessionWarning = "session_warning"
+	// MetaSessionFinal is set to "true" on the T-FinalWarningLead event
+	// only. Consumers that need to auto-open the SessionAboutToExpire
+	// dialog gate on this; T-WarningLead events leave the field unset.
+	MetaSessionFinal = "session_final_warning"
+	// MetaSessionExpiresAt carries the absolute UTC deadline encoded with
+	// FormatExpiresAt; consumers must decode with ParseExpiresAt so a
+	// future format change stays a single edit.
+	MetaSessionExpiresAt = "session_expires_at"
+	// MetaSessionLeadMinutes carries the lead in whole minutes (WarningLead
+	// for the T-10 event, FinalWarningLead for the T-2 event) so the UI
+	// can show "expires in ~N minutes" without hardcoding either constant.
+	MetaSessionLeadMinutes = "lead_minutes"
+)
+
+// expiresAtLayout is the wire format used for MetaSessionExpiresAt.
+// Producer and consumers both go through FormatExpiresAt/ParseExpiresAt
+// so this layout stays a single source of truth.
+const expiresAtLayout = time.RFC3339
+
+// FormatExpiresAt encodes a deadline for MetaSessionExpiresAt. Always
+// emits UTC so a consumer in another timezone reads the same wall-clock
+// deadline.
+func FormatExpiresAt(t time.Time) string {
+	return t.UTC().Format(expiresAtLayout)
+}
+
+// ParseExpiresAt decodes the MetaSessionExpiresAt value back to a UTC
+// time. Returns an error when the field is empty or malformed; the
+// caller decides whether to fall back (zero value) or propagate.
+func ParseExpiresAt(s string) (time.Time, error) {
+	t, err := time.Parse(expiresAtLayout, s)
+	if err != nil {
+		return time.Time{}, err
+	}
+	return t.UTC(), nil
+}
+
+// FormatLeadMinutes encodes a lead duration for MetaSessionLeadMinutes
+// as the integer count of whole minutes. Sub-minute residuals are
+// truncated — the field is informational ("expires in ~N minutes") and
+// fractional minutes don't change what the UI displays.
+func FormatLeadMinutes(d time.Duration) string {
+	return strconv.Itoa(int(d / time.Minute))
+}
+
+// ParseLeadMinutes decodes a MetaSessionLeadMinutes value. Returns 0
+// and the parse error for malformed input; consumers that prefer a
+// silent fallback can simply ignore the error.
+func ParseLeadMinutes(s string) (int, error) {
+	return strconv.Atoi(s)
+}

client/internal/auth/sessionwatch/watcher.go

@@ -0,0 +1,362 @@
+// Package sessionwatch tracks the SSO session expiry deadline that the
+// management server publishes via LoginResponse / SyncResponse and fires
+// two warning events at fixed lead times before expiry: an interactive
+// T-WarningLead notification and a dismiss-gated T-FinalWarningLead
+// fallback dialog.
+//
+// The watcher is idempotent: Update may be called as often as the network
+// map snapshots arrive. Repeating the same deadline is a no-op; a new
+// deadline reschedules the timers and arms a fresh warning cycle.
+//
+// Warning firing is edge-detected. Each unique deadline value fires each
+// warning callback at most once.
+package sessionwatch
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+
+	cProto "github.com/netbirdio/netbird/client/proto"
+)
+
+const (
+	// Skew tolerates a small clock difference between the management
+	// server and this peer before treating a deadline as "in the past".
+	// Slightly above typical NTP drift; tight enough that the UI doesn't
+	// paint a stale expiry as if it were valid.
+	Skew = 30 * time.Second
+
+	// maxDeadlineHorizon caps how far in the future an accepted deadline
+	// can sit. A timestamp beyond this is almost certainly a protocol
+	// glitch, and silently arming a 100-year timer would hide the bug.
+	maxDeadlineHorizon = 10 * 365 * 24 * time.Hour
+
+	// WarningLead is how far before expiry the first (interactive)
+	// warning fires. Drives the T-10 OS notification with
+	// Extend/Dismiss actions.
+	WarningLead = 10 * time.Minute
+
+	// FinalWarningLead is how far before expiry the fallback final
+	// warning fires. Drives the auto-opened SessionAboutToExpire dialog,
+	// but only when the user has not dismissed the T-WarningLead warning
+	// for the same deadline. Must be strictly less than WarningLead.
+	FinalWarningLead = 2 * time.Minute
+)
+
+var (
+	// ErrDeadlineBeforeEpoch is returned by Update when the supplied
+	// deadline pre-dates 1970-01-01.
+	ErrDeadlineBeforeEpoch = errors.New("session deadline before unix epoch")
+
+	// ErrDeadlineTooFarFuture is returned by Update when the supplied
+	// deadline is more than maxDeadlineHorizon in the future.
+	ErrDeadlineTooFarFuture = errors.New("session deadline too far in the future")
+
+	// ErrDeadlineInPast is returned by Update when the supplied deadline
+	// is more than Skew in the past.
+	ErrDeadlineInPast = errors.New("session deadline in the past")
+)
+
+// StatusRecorder is the side-effect surface the watcher drives on every
+// state transition. Production wires this to peer.Status (NotifyStateChange
+// for deadline change/clear, PublishEvent for the two warnings); tests pass
+// a fake recorder so the same surface is observable without an engine.
+//
+// PublishEvent's signature mirrors peer.Status.PublishEvent: the watcher
+// composes the metadata internally so the wire format (MetaSession*) is
+// owned by sessionwatch, not the caller.
+type StatusRecorder interface {
+	NotifyStateChange()
+	PublishEvent(
+		severity cProto.SystemEvent_Severity,
+		category cProto.SystemEvent_Category,
+		message string,
+		userMessage string,
+		metadata map[string]string,
+	)
+}
+
+// Watcher observes the latest session deadline and fires two warnings
+// before it expires: the interactive T-WarningLead notification, and the
+// fallback T-FinalWarningLead dialog (suppressed when the user dismissed
+// the first one for the same deadline). Safe for concurrent use.
+type Watcher struct {
+	lead      time.Duration
+	finalLead time.Duration
+
+	mu           sync.Mutex
+	current      time.Time
+	timer        *time.Timer
+	finalTimer   *time.Timer
+	firedAt      time.Time // deadline value the T-WarningLead callback last fired against
+	finalFiredAt time.Time // deadline value the T-FinalWarningLead callback last fired against
+	dismissedAt  time.Time // deadline value the user dismissed via Dismiss(); gates fireFinal
+	closed       bool
+	recorder     StatusRecorder
+}
+
+// New returns a watcher with the package defaults WarningLead and
+// FinalWarningLead. Pass nil for recorder to silence side effects (handy
+// in unit tests that exercise sanity checks without observing the publish
+// path).
+func New(recorder StatusRecorder) *Watcher {
+	return NewWithLeads(WarningLead, FinalWarningLead, recorder)
+}
+
+// NewWithLeads returns a watcher with custom lead times. Useful for tests.
+// final must be strictly less than lead; otherwise both timers fire in the
+// wrong order or simultaneously and the UI flow breaks. A zero final lead
+// disables the final-warning timer entirely (see armTimerLocked) so a
+// millisecond-scale deadline doesn't flush both timers in one tick.
+func NewWithLeads(lead, final time.Duration, recorder StatusRecorder) *Watcher {
+	return &Watcher{
+		lead:      lead,
+		finalLead: final,
+		recorder:  recorder,
+	}
+}
+
+// Update sets the latest deadline. Pass the zero time to clear (e.g. when
+// a Sync push from the server omits the field because login expiration
+// was disabled).
+//
+// Same-value updates are no-ops. A different non-zero value cancels any
+// pending timer, resets the "already fired" guard, and arms a new one.
+//
+// Returns one of the sentinel Err* values when the deadline fails the
+// sanity checks (pre-epoch, far future, or in the past beyond Skew).
+// In every error case the watcher first clears its state so it stays
+// consistent with what the caller will push into its other sinks (e.g.
+// applySessionDeadline forces a zero deadline into the status recorder
+// after a non-nil error).
+func (w *Watcher) Update(deadline time.Time) error {
+	w.mu.Lock()
+	if w.closed {
+		w.mu.Unlock()
+		return nil
+	}
+
+	if deadline.IsZero() {
+		w.clearLocked()
+		return nil
+	}
+
+	now := time.Now()
+	switch {
+	case deadline.Before(time.Unix(0, 0)):
+		w.clearLocked()
+		return fmt.Errorf("%w: %v", ErrDeadlineBeforeEpoch, deadline)
+	case deadline.After(now.Add(maxDeadlineHorizon)):
+		w.clearLocked()
+		return fmt.Errorf("%w: %v", ErrDeadlineTooFarFuture, deadline)
+	case deadline.Before(now.Add(-Skew)):
+		w.clearLocked()
+		return fmt.Errorf("%w: %v (now=%v)", ErrDeadlineInPast, deadline, now)
+	}
+
+	if deadline.Equal(w.current) {
+		w.mu.Unlock()
+		return nil
+	}
+
+	w.stopTimerLocked()
+	w.current = deadline
+	// Reset every per-deadline guard so a refreshed deadline arms a fresh
+	// warning cycle: both edge triggers and the user Dismiss decision
+	// (the user agreed to the old deadline expiring; a new deadline
+	// restarts the contract).
+	w.firedAt = time.Time{}
+	w.finalFiredAt = time.Time{}
+	w.dismissedAt = time.Time{}
+
+	w.armTimerLocked(deadline)
+	recorder := w.recorder
+	w.mu.Unlock()
+	if recorder != nil {
+		recorder.NotifyStateChange()
+	}
+	log.Infof("auth session deadline set to: %s (in %s)", deadline.Format(time.RFC3339), time.Until(deadline).Round(time.Second))
+	return nil
+}
+
+// Deadline returns the most recently observed deadline. Zero when no
+// deadline is currently tracked.
+func (w *Watcher) Deadline() time.Time {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	return w.current
+}
+
+// Dismiss records the user's "Dismiss" action against the current deadline
+// and suppresses the upcoming final-warning callback for that deadline.
+// Idempotent: repeated calls are no-ops. A subsequent Update with a fresh
+// deadline resets the dismissal so the final-warning cycle re-arms.
+//
+// No-op when the watcher holds no deadline or has been closed.
+func (w *Watcher) Dismiss() {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.closed || w.current.IsZero() {
+		return
+	}
+	if w.dismissedAt.Equal(w.current) {
+		return
+	}
+	w.dismissedAt = w.current
+	// Cancel the armed final-warning timer eagerly. fireFinal would also
+	// gate on dismissedAt, but stopping the timer avoids a wakeup with
+	// nothing to do and makes the intent visible.
+	if w.finalTimer != nil {
+		w.finalTimer.Stop()
+		w.finalTimer = nil
+	}
+	log.Infof("auth session final-warning dismissed for deadline %s", w.current.Format(time.RFC3339))
+}
+
+// Close stops any pending timer. Update calls after Close are ignored.
+func (w *Watcher) Close() {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.closed {
+		return
+	}
+	w.closed = true
+	w.stopTimerLocked()
+}
+
+// clearLocked drops the tracked deadline and notifies the recorder so
+// downstream consumers (SubscribeStatus stream, UI) drop their anchor.
+// The caller must hold w.mu; this helper releases it before invoking
+// the recorder.
+func (w *Watcher) clearLocked() {
+	if w.current.IsZero() {
+		w.mu.Unlock()
+		return
+	}
+	w.stopTimerLocked()
+	w.current = time.Time{}
+	w.firedAt = time.Time{}
+	w.finalFiredAt = time.Time{}
+	w.dismissedAt = time.Time{}
+	recorder := w.recorder
+	w.mu.Unlock()
+	if recorder != nil {
+		recorder.NotifyStateChange()
+	}
+	log.Infof("auth session deadline cleared")
+}
+
+func (w *Watcher) stopTimerLocked() {
+	if w.timer != nil {
+		w.timer.Stop()
+		w.timer = nil
+	}
+	if w.finalTimer != nil {
+		w.finalTimer.Stop()
+		w.finalTimer = nil
+	}
+}
+
+func (w *Watcher) armTimerLocked(deadline time.Time) {
+	w.timer = armOneShotLocked(deadline.Add(-w.lead), func() { w.fire(deadline) })
+	// finalLead <= 0 disables the final-warning timer entirely. Used by
+	// tests that predate the final-warning fallback so a millisecond-scale
+	// deadline does not flush both timers at once.
+	if w.finalLead > 0 {
+		w.finalTimer = armOneShotLocked(deadline.Add(-w.finalLead), func() { w.fireFinal(deadline) })
+	}
+}
+
+func (w *Watcher) fire(armedFor time.Time) {
+	w.mu.Lock()
+	if w.closed || !w.current.Equal(armedFor) {
+		// Deadline moved while we were waiting (e.g. a successful extend).
+		// The reschedule path armed a fresh timer; this one is stale.
+		w.mu.Unlock()
+		return
+	}
+	if !w.firedAt.IsZero() && w.firedAt.Equal(armedFor) {
+		w.mu.Unlock()
+		return
+	}
+	w.firedAt = armedFor
+	recorder := w.recorder
+	w.mu.Unlock()
+	if recorder == nil {
+		return
+	}
+	log.Infof("auth session expiry soon warning fired")
+	publishWarning(recorder, armedFor, false)
+}
+
+// fireFinal mirrors fire for the T-FinalWarningLead timer with an extra
+// dismiss-gate: if the user dismissed the T-WarningLead notification for
+// this deadline, the final warning is suppressed entirely.
+func (w *Watcher) fireFinal(armedFor time.Time) {
+	w.mu.Lock()
+	if w.closed || !w.current.Equal(armedFor) {
+		w.mu.Unlock()
+		return
+	}
+	if !w.finalFiredAt.IsZero() && w.finalFiredAt.Equal(armedFor) {
+		w.mu.Unlock()
+		return
+	}
+	if w.dismissedAt.Equal(armedFor) {
+		w.mu.Unlock()
+		log.Infof("auth session final-warning skipped (dismissed by user)")
+		return
+	}
+	w.finalFiredAt = armedFor
+	recorder := w.recorder
+	w.mu.Unlock()
+	if recorder == nil {
+		return
+	}
+	log.Infof("auth session final-warning fired")
+	publishWarning(recorder, armedFor, true)
+}
+
+// armOneShotLocked schedules cb at fireAt. When fireAt is already in the
+// past it dispatches on the next scheduler tick so a state-change recorder
+// notification (invoked after w.mu is released) lands first. Caller must
+// hold w.mu.
+func armOneShotLocked(fireAt time.Time, cb func()) *time.Timer {
+	delay := time.Until(fireAt)
+	if delay <= 0 {
+		return time.AfterFunc(0, cb)
+	}
+	return time.AfterFunc(delay, cb)
+}
+
+// publishWarning composes the SystemEvent for a watcher-fired warning and
+// pushes it through the recorder. Severity is CRITICAL on both — bypassing
+// the user's Notifications toggle is deliberate: missing the warning
+// window forces the post-mortem SessionExpired flow (tunnel torn down,
+// lock icon, manual re-login), which is the UX we are trying to avoid.
+func publishWarning(recorder StatusRecorder, deadline time.Time, final bool) {
+	lead := WarningLead
+	message := "session expiry warning"
+	meta := map[string]string{
+		MetaSessionWarning:   "true",
+		MetaSessionExpiresAt: FormatExpiresAt(deadline),
+	}
+	if final {
+		lead = FinalWarningLead
+		message = "session expiry final warning"
+		meta[MetaSessionFinal] = "true"
+	}
+	meta[MetaSessionLeadMinutes] = FormatLeadMinutes(lead)
+
+	recorder.PublishEvent(
+		cProto.SystemEvent_CRITICAL,
+		cProto.SystemEvent_AUTHENTICATION,
+		message,
+		"",
+		meta,
+	)
+}

client/internal/auth/sessionwatch/watcher_test.go

@@ -0,0 +1,463 @@
+package sessionwatch
+
+import (
+	"errors"
+	"sync"
+	"testing"
+	"time"
+
+	cProto "github.com/netbirdio/netbird/client/proto"
+)
+
+// fakeRecorder satisfies StatusRecorder and records every call so tests
+// can observe what the watcher emits. NotifyStateChange and PublishEvent
+// land in the same ordered events slice (with the Kind distinguishing
+// them) so tests that care about ordering still work.
+type fakeRecorder struct {
+	mu     sync.Mutex
+	events []event
+}
+
+type eventKind int
+
+const (
+	stateChange eventKind = iota
+	publish
+)
+
+type event struct {
+	kind eventKind
+	// Set only for publish events.
+	severity cProto.SystemEvent_Severity
+	category cProto.SystemEvent_Category
+	message  string
+	meta     map[string]string
+}
+
+func (r *fakeRecorder) NotifyStateChange() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.events = append(r.events, event{kind: stateChange})
+}
+
+func (r *fakeRecorder) PublishEvent(
+	severity cProto.SystemEvent_Severity,
+	category cProto.SystemEvent_Category,
+	message string,
+	_ string,
+	metadata map[string]string,
+) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.events = append(r.events, event{
+		kind:     publish,
+		severity: severity,
+		category: category,
+		message:  message,
+		meta:     metadata,
+	})
+}
+
+func (r *fakeRecorder) snapshot() []event {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	out := make([]event, len(r.events))
+	copy(out, r.events)
+	return out
+}
+
+func (e event) isFinalWarning() bool {
+	return e.kind == publish && e.meta[MetaSessionFinal] == "true"
+}
+
+func (e event) isWarning() bool {
+	return e.kind == publish && e.meta[MetaSessionWarning] == "true" && e.meta[MetaSessionFinal] != "true"
+}
+
+func countWhere(events []event, pred func(event) bool) int {
+	n := 0
+	for _, e := range events {
+		if pred(e) {
+			n++
+		}
+	}
+	return n
+}
+
+func waitForEvents(t *testing.T, r *fakeRecorder, want int) []event {
+	t.Helper()
+	deadline := time.Now().Add(500 * time.Millisecond)
+	for time.Now().Before(deadline) {
+		if got := r.snapshot(); len(got) >= want {
+			return got
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	got := r.snapshot()
+	t.Fatalf("timed out waiting for %d events, got %d: %+v", want, len(got), got)
+	return nil
+}
+
+// newWatcher builds a watcher with the final timer disabled (finalLead=0),
+// matching the lead-only behaviour the pre-final-warning tests assume.
+func newWatcher(lead time.Duration, r *fakeRecorder) *Watcher {
+	return NewWithLeads(lead, 0, r)
+}
+
+func TestUpdateZeroBeforeAnythingIsNoop(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	w.Update(time.Time{})
+
+	if got := r.snapshot(); len(got) != 0 {
+		t.Fatalf("expected no events on initial zero, got %+v", got)
+	}
+}
+
+func TestUpdateNonZeroFiresStateChange(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	d := time.Now().Add(time.Hour)
+	w.Update(d)
+
+	events := waitForEvents(t, r, 1)
+	if events[0].kind != stateChange {
+		t.Fatalf("expected stateChange, got %+v", events[0])
+	}
+	if !w.Deadline().Equal(d) {
+		t.Fatalf("deadline mismatch: %v vs %v", w.Deadline(), d)
+	}
+}
+
+func TestSameDeadlineIsNoop(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	d := time.Now().Add(time.Hour)
+	w.Update(d)
+	w.Update(d)
+	w.Update(d)
+
+	events := waitForEvents(t, r, 1)
+	if len(events) != 1 {
+		t.Fatalf("expected exactly 1 event for repeated same deadline, got %d: %+v", len(events), events)
+	}
+}
+
+func TestWarningFiresOnceWithinLeadWindow(t *testing.T) {
+	r := &fakeRecorder{}
+	lead := 50 * time.Millisecond
+	w := newWatcher(lead, r)
+	defer w.Close()
+
+	// Deadline 80ms out — warning should fire after ~30ms.
+	d := time.Now().Add(80 * time.Millisecond)
+	w.Update(d)
+
+	events := waitForEvents(t, r, 2)
+	if events[0].kind != stateChange {
+		t.Fatalf("event[0] should be stateChange, got %+v", events[0])
+	}
+	if !events[1].isWarning() {
+		t.Fatalf("event[1] should be a warning publish, got %+v", events[1])
+	}
+}
+
+func TestWarningFiresImmediatelyWhenAlreadyInsideWindow(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(time.Hour, r) // lead > delta => fire immediately
+	defer w.Close()
+
+	d := time.Now().Add(10 * time.Millisecond)
+	w.Update(d)
+
+	events := waitForEvents(t, r, 2)
+	if !events[1].isWarning() {
+		t.Fatalf("expected immediate warning publish, got %+v", events[1])
+	}
+}
+
+func TestNewDeadlineCancelsPriorTimer(t *testing.T) {
+	r := &fakeRecorder{}
+	lead := 50 * time.Millisecond
+	w := newWatcher(lead, r)
+	defer w.Close()
+
+	first := time.Now().Add(80 * time.Millisecond) // would fire warning ~30ms in
+	w.Update(first)
+
+	// Replace with a far-future deadline before the warning fires.
+	time.Sleep(5 * time.Millisecond)
+	second := time.Now().Add(time.Hour)
+	w.Update(second)
+
+	// Wait past when first's warning would have fired.
+	time.Sleep(80 * time.Millisecond)
+
+	if n := countWhere(r.snapshot(), event.isWarning); n != 0 {
+		t.Fatalf("warning fired for cancelled deadline: %+v", r.snapshot())
+	}
+}
+
+func TestRefreshAfterFireArmsNewWarning(t *testing.T) {
+	r := &fakeRecorder{}
+	lead := 30 * time.Millisecond
+	w := newWatcher(lead, r)
+	defer w.Close()
+
+	first := time.Now().Add(50 * time.Millisecond)
+	w.Update(first)
+
+	// Wait for stateChange + warning of the first cycle.
+	waitForEvents(t, r, 2)
+
+	// Simulate a successful extend: brand new deadline.
+	second := time.Now().Add(60 * time.Millisecond)
+	w.Update(second)
+
+	// 4 events total: stateChange, warning (first), stateChange, warning (second).
+	events := waitForEvents(t, r, 4)
+	if events[2].kind != stateChange {
+		t.Fatalf("event[2] should be stateChange for the new deadline, got %+v", events[2])
+	}
+	if !events[3].isWarning() {
+		t.Fatalf("event[3] should be a warning publish for the new deadline, got %+v", events[3])
+	}
+}
+
+func TestUpdateZeroAfterNonZeroClearsState(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(time.Hour, r)
+	defer w.Close()
+
+	d := time.Now().Add(2 * time.Hour)
+	w.Update(d)
+	waitForEvents(t, r, 1)
+
+	w.Update(time.Time{})
+
+	events := waitForEvents(t, r, 2)
+	if events[1].kind != stateChange {
+		t.Fatalf("expected stateChange on clear, got %+v", events[1])
+	}
+	if !w.Deadline().IsZero() {
+		t.Fatalf("Deadline should be zero after clear")
+	}
+}
+
+func TestUpdateRejectsBeforeEpoch(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	good := time.Now().Add(time.Hour)
+	if err := w.Update(good); err != nil {
+		t.Fatalf("seed Update: %v", err)
+	}
+
+	err := w.Update(time.Unix(-100, 0))
+	if !errors.Is(err, ErrDeadlineBeforeEpoch) {
+		t.Fatalf("want ErrDeadlineBeforeEpoch, got %v", err)
+	}
+	if !w.Deadline().IsZero() {
+		t.Fatalf("rejected pre-epoch update must clear deadline; got %v", w.Deadline())
+	}
+}
+
+func TestUpdateRejectsTooFarFuture(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	good := time.Now().Add(time.Hour)
+	if err := w.Update(good); err != nil {
+		t.Fatalf("seed Update: %v", err)
+	}
+
+	err := w.Update(time.Now().Add(50 * 365 * 24 * time.Hour))
+	if !errors.Is(err, ErrDeadlineTooFarFuture) {
+		t.Fatalf("want ErrDeadlineTooFarFuture, got %v", err)
+	}
+	if !w.Deadline().IsZero() {
+		t.Fatalf("rejected far-future update must clear deadline; got %v", w.Deadline())
+	}
+}
+
+func TestUpdateInPastClearsDeadline(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	good := time.Now().Add(time.Hour)
+	if err := w.Update(good); err != nil {
+		t.Fatalf("seed Update: %v", err)
+	}
+	// Drain the stateChange from the seed.
+	waitForEvents(t, r, 1)
+
+	err := w.Update(time.Now().Add(-1 * time.Hour))
+	if !errors.Is(err, ErrDeadlineInPast) {
+		t.Fatalf("want ErrDeadlineInPast, got %v", err)
+	}
+	if !w.Deadline().IsZero() {
+		t.Fatalf("in-past update must clear the deadline, got %v", w.Deadline())
+	}
+	events := waitForEvents(t, r, 2)
+	if events[1].kind != stateChange {
+		t.Fatalf("expected stateChange on clear, got %+v", events[1])
+	}
+}
+
+func TestUpdateWithinSkewAccepted(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	// 5 seconds in the past is within the 30s Skew tolerance — accept it.
+	d := time.Now().Add(-5 * time.Second)
+	if err := w.Update(d); err != nil {
+		t.Fatalf("within-skew Update should succeed, got %v", err)
+	}
+	if !w.Deadline().Equal(d) {
+		t.Fatalf("expected deadline to be applied, got %v want %v", w.Deadline(), d)
+	}
+}
+
+func TestCloseSilencesUpdates(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	w.Close()
+
+	w.Update(time.Now().Add(time.Hour))
+
+	time.Sleep(20 * time.Millisecond)
+	if got := r.snapshot(); len(got) != 0 {
+		t.Fatalf("expected no events after Close, got %+v", got)
+	}
+}
+
+func TestFinalWarningFiresAfterRegularWarning(t *testing.T) {
+	r := &fakeRecorder{}
+	// Warning fires at deadline-80ms, final at deadline-30ms.
+	w := NewWithLeads(80*time.Millisecond, 30*time.Millisecond, r)
+	defer w.Close()
+
+	d := time.Now().Add(100 * time.Millisecond)
+	w.Update(d)
+
+	// Expect stateChange + warning + final-warning.
+	events := waitForEvents(t, r, 3)
+
+	if countWhere(events, func(e event) bool { return e.kind == stateChange }) != 1 {
+		t.Fatalf("expected exactly 1 stateChange, got %+v", events)
+	}
+	if countWhere(events, event.isWarning) != 1 {
+		t.Fatalf("expected exactly 1 warning publish, got %+v", events)
+	}
+	if countWhere(events, event.isFinalWarning) != 1 {
+		t.Fatalf("expected exactly 1 final-warning publish, got %+v", events)
+	}
+
+	// Warning must precede final (same deadline, longer lead fires first).
+	var wIdx, fIdx int
+	for i, e := range events {
+		switch {
+		case e.isWarning():
+			wIdx = i
+		case e.isFinalWarning():
+			fIdx = i
+		}
+	}
+	if wIdx > fIdx {
+		t.Fatalf("warning must publish before final-warning, got order %+v", events)
+	}
+}
+
+func TestDismissSuppressesFinalWarning(t *testing.T) {
+	r := &fakeRecorder{}
+	w := NewWithLeads(80*time.Millisecond, 30*time.Millisecond, r)
+	defer w.Close()
+
+	d := time.Now().Add(100 * time.Millisecond)
+	w.Update(d)
+
+	// Wait for the warning publish so we know we're inside the warning
+	// window, then dismiss before the final timer would fire.
+	deadline := time.Now().Add(500 * time.Millisecond)
+	for time.Now().Before(deadline) {
+		if countWhere(r.snapshot(), event.isWarning) >= 1 {
+			break
+		}
+		time.Sleep(2 * time.Millisecond)
+	}
+	if countWhere(r.snapshot(), event.isWarning) < 1 {
+		t.Fatalf("warning did not publish in time, events=%+v", r.snapshot())
+	}
+
+	w.Dismiss()
+
+	// Now wait past when the final would have fired.
+	time.Sleep(120 * time.Millisecond)
+
+	if n := countWhere(r.snapshot(), event.isFinalWarning); n != 0 {
+		t.Fatalf("final-warning published after Dismiss(), events=%+v", r.snapshot())
+	}
+}
+
+func TestDismissResetByNewDeadline(t *testing.T) {
+	r := &fakeRecorder{}
+	w := NewWithLeads(80*time.Millisecond, 30*time.Millisecond, r)
+	defer w.Close()
+
+	first := time.Now().Add(100 * time.Millisecond)
+	w.Update(first)
+
+	// Dismiss against the first deadline.
+	w.Dismiss()
+
+	// Replace with a fresh deadline before the first's timers complete.
+	time.Sleep(10 * time.Millisecond)
+	second := time.Now().Add(100 * time.Millisecond)
+	w.Update(second)
+
+	// The second cycle must publish a final-warning (the dismiss state
+	// did not carry over).
+	deadline := time.Now().Add(500 * time.Millisecond)
+	for time.Now().Before(deadline) {
+		if countWhere(r.snapshot(), event.isFinalWarning) >= 1 {
+			break
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	if countWhere(r.snapshot(), event.isFinalWarning) < 1 {
+		t.Fatalf("final-warning did not publish on fresh deadline after Dismiss reset, events=%+v", r.snapshot())
+	}
+}
+
+func TestDismissBeforeUpdateIsNoop(t *testing.T) {
+	r := &fakeRecorder{}
+	w := NewWithLeads(80*time.Millisecond, 30*time.Millisecond, r)
+	defer w.Close()
+
+	// No deadline tracked yet; Dismiss must be a no-op (no panic, no state).
+	w.Dismiss()
+
+	d := time.Now().Add(100 * time.Millisecond)
+	w.Update(d)
+
+	// Final warning should still publish — Dismiss only acts on the current
+	// deadline, and there was none at the time of the call.
+	deadline := time.Now().Add(500 * time.Millisecond)
+	for time.Now().Before(deadline) {
+		if countWhere(r.snapshot(), event.isFinalWarning) >= 1 {
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	t.Fatalf("final-warning did not publish after no-op pre-Update Dismiss, events=%+v", r.snapshot())
+}

client/internal/connect.go

@@ -393,6 +393,10 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 			return wrapErr(err)
 		}
 
+		// Seed the session-expiry deadline from the LoginResponse. Subsequent
+		// changes flow in through SyncResponse and are applied in handleSync.
+		engine.ApplySessionDeadline(loginResp.GetSessionExpiresAt())
+
 		log.Infof("Netbird engine started, the IP is: %s", peerConfig.GetAddress())
 		state.Set(StatusConnected)
 

client/internal/engine.go

@@ -35,6 +35,7 @@ import (
 	"github.com/netbirdio/netbird/client/iface/udpmux"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/acl"
+	"github.com/netbirdio/netbird/client/internal/auth/sessionwatch"
 	"github.com/netbirdio/netbird/client/internal/debug"
 	"github.com/netbirdio/netbird/client/internal/dns"
 	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
@@ -250,6 +251,8 @@ type Engine struct {
 	jobExecutorWG sync.WaitGroup
 
 	exposeManager *expose.Manager
+
+	sessionWatcher *sessionwatch.Watcher
 }
 
 // Peer is an instance of the Connection Peer
@@ -293,6 +296,17 @@ func NewEngine(
 		clientMetrics:      services.ClientMetrics,
 		updateManager:      services.UpdateManager,
 	}
+	// sessionWatcher keeps the SubscribeStatus consumers in sync with the
+	// session expiry deadline. Deadline-change ticks come for free via
+	// Status.SetSessionExpiresAt; the watcher exists to push a wake-up at
+	// T-WarningLead and T-FinalWarningLead so the UI repaints the remaining
+	// time / warning state even when nothing else changed, and to publish
+	// two SystemEvents (the warning composition lives in sessionwatch so
+	// the wire format stays owned by one package):
+	//   - T-WarningLead   → interactive "Extend now / Dismiss" notification
+	//   - T-FinalWarningLead → auto-opened SessionAboutToExpire dialog,
+	//     suppressed when the user dismissed the earlier warning
+	engine.sessionWatcher = sessionwatch.New(engine.statusRecorder)
 
 	log.Infof("I am: %s", config.WgPrivateKey.PublicKey().String())
 	return engine
@@ -333,6 +347,10 @@ func (e *Engine) Stop() error {
 		e.srWatcher.Close()
 	}
 
+	if e.sessionWatcher != nil {
+		e.sessionWatcher.Close()
+	}
+
 	if e.updateManager != nil {
 		e.updateManager.SetDownloadOnly()
 	}
@@ -865,6 +883,8 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 		return e.ctx.Err()
 	}
 
+	e.ApplySessionDeadline(update.GetSessionExpiresAt())
+
 	if update.NetworkMap != nil && update.NetworkMap.PeerConfig != nil {
 		e.handleAutoUpdateVersion(update.NetworkMap.PeerConfig.AutoUpdate)
 	}

client/internal/engine_authsession.go

@@ -0,0 +1,97 @@
+package internal
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"google.golang.org/protobuf/types/known/timestamppb"
+
+	"github.com/netbirdio/netbird/client/system"
+)
+
+// ApplySessionDeadline propagates the absolute SSO session deadline carried on
+// LoginResponse / SyncResponse to both the watcher (for the edge-triggered
+// warning) and the status recorder (for the SubscribeStatus / Status RPC
+// snapshot the UI consumes).
+//
+// The wire field is 3-state:
+//   - nil                        → snapshot carries no info; keep the
+//     previously-anchored deadline (no-op)
+//   - explicit zero (s=0, n=0)   → peer is not SSO-registered or expiry is
+//     disabled; clear both sinks
+//   - valid timestamp            → new deadline; arm watcher, expose on
+//     status recorder
+//
+// Deadline sanity-checks live in sessionwatch.Watcher.Update. Any rejected
+// value is treated as a clear on both sinks: the alternative — leaving the
+// previously-known deadline in place — risks the UI confidently displaying
+// a stale "expires in X" while the server has actually invalidated it.
+func (e *Engine) ApplySessionDeadline(ts *timestamppb.Timestamp) {
+	if ts == nil {
+		return
+	}
+	var deadline time.Time
+	// Explicit zero (seconds=0 AND nanos=0) is the sentinel for "disabled".
+	// Everything else flows through Watcher.Update, whose sanity-checks
+	// reject out-of-range / pre-epoch / far-future / too-stale values; the
+	// catch-block below converts any rejection into a clear.
+	if ts.GetSeconds() != 0 || ts.GetNanos() != 0 {
+		deadline = ts.AsTime().UTC()
+	}
+	if e.sessionWatcher != nil {
+		if err := e.sessionWatcher.Update(deadline); err != nil {
+			log.Errorf("auth session deadline rejected: %v, clearing", err)
+			deadline = time.Time{}
+		}
+	}
+	if e.statusRecorder != nil {
+		e.statusRecorder.SetSessionExpiresAt(deadline)
+	}
+}
+
+// DismissSessionWarning records the user's "Dismiss" click on the
+// T-WarningLead interactive notification and suppresses the upcoming
+// T-FinalWarningLead fallback for the current deadline. No-op when the
+// watcher is not running or holds no deadline.
+func (e *Engine) DismissSessionWarning() {
+	if e.sessionWatcher == nil {
+		return
+	}
+	e.sessionWatcher.Dismiss()
+}
+
+// ExtendAuthSession asks the management server to refresh the SSO session
+// expiry deadline using the supplied JWT, then mirrors the new deadline into
+// the daemon's state. The tunnel is untouched; no resync, no reconnect.
+//
+// Returns the new absolute UTC deadline (or zero time when the server
+// reports the peer is not eligible for extension).
+func (e *Engine) ExtendAuthSession(ctx context.Context, jwtToken string) (time.Time, error) {
+	if jwtToken == "" {
+		return time.Time{}, errors.New("jwt token is required")
+	}
+	if e.mgmClient == nil {
+		return time.Time{}, errors.New("management client is not initialised")
+	}
+
+	info, err := system.GetInfoWithChecks(ctx, e.checks)
+	if err != nil {
+		log.Warnf("failed to collect system info for session extend: %v", err)
+		info = system.GetInfo(ctx)
+	}
+
+	resp, err := e.mgmClient.ExtendAuthSession(info, jwtToken)
+	if err != nil {
+		return time.Time{}, fmt.Errorf("extend auth session on management: %w", err)
+	}
+
+	e.ApplySessionDeadline(resp.GetSessionExpiresAt())
+
+	if resp.GetSessionExpiresAt().IsValid() {
+		return resp.GetSessionExpiresAt().AsTime().UTC(), nil
+	}
+	return time.Time{}, nil
+}

client/internal/engine_session_deadline_test.go

@@ -0,0 +1,78 @@
+package internal
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/types/known/timestamppb"
+
+	"github.com/netbirdio/netbird/client/internal/auth/sessionwatch"
+	"github.com/netbirdio/netbird/client/internal/peer"
+)
+
+// TestApplySessionDeadline_ThreeState pins down the 3-state semantics of the
+// wire field carried on LoginResponse / SyncResponse:
+//
+//   - nil pointer            → no info; previously-anchored deadline survives
+//   - explicit zero value    → "expiry disabled" sentinel; both sinks cleared
+//   - valid future timestamp → new deadline propagated to both sinks
+func TestApplySessionDeadline_ThreeState(t *testing.T) {
+	newEngine := func() *Engine {
+		recorder := peer.NewRecorder("")
+		return &Engine{
+			statusRecorder: recorder,
+			sessionWatcher: sessionwatch.New(recorder),
+		}
+	}
+
+	t.Run("valid timestamp sets deadline on both sinks", func(t *testing.T) {
+		e := newEngine()
+		deadline := time.Now().Add(time.Hour).UTC().Truncate(time.Second)
+
+		e.ApplySessionDeadline(timestamppb.New(deadline))
+
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(deadline),
+			"status recorder should hold the new deadline")
+	})
+
+	t.Run("nil is a no-op and preserves previous deadline", func(t *testing.T) {
+		e := newEngine()
+		seeded := time.Now().Add(time.Hour).UTC().Truncate(time.Second)
+		e.ApplySessionDeadline(timestamppb.New(seeded))
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(seeded))
+
+		e.ApplySessionDeadline(nil)
+
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(seeded),
+			"nil snapshot must not disturb the existing deadline")
+	})
+
+	t.Run("explicit zero clears a previously-anchored deadline", func(t *testing.T) {
+		e := newEngine()
+		seeded := time.Now().Add(time.Hour).UTC().Truncate(time.Second)
+		e.ApplySessionDeadline(timestamppb.New(seeded))
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(seeded))
+
+		// Explicit zero Timestamp{} (seconds=0, nanos=0) is the
+		// "expiry disabled / not SSO" sentinel.
+		e.ApplySessionDeadline(&timestamppb.Timestamp{})
+
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().IsZero(),
+			"explicit zero sentinel must clear the deadline")
+	})
+
+	t.Run("invalid timestamp clears the deadline", func(t *testing.T) {
+		e := newEngine()
+		seeded := time.Now().Add(time.Hour).UTC().Truncate(time.Second)
+		e.ApplySessionDeadline(timestamppb.New(seeded))
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(seeded))
+
+		// Out-of-range nanos → IsValid()==false; same-meaning as the
+		// disabled sentinel for downstream sinks.
+		e.ApplySessionDeadline(&timestamppb.Timestamp{Seconds: 1, Nanos: -1})
+
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().IsZero(),
+			"invalid timestamp must clear the deadline")
+	})
+}

client/internal/peer/status.go

@@ -202,6 +202,12 @@ type Status struct {
 	notifier              *notifier
 	rosenpassEnabled      bool
 	rosenpassPermissive   bool
+	// sessionExpiresAt is the absolute UTC instant at which the peer's SSO
+	// session expires. Zero when the peer is not SSO-tracked or login
+	// expiration is disabled. Populated from management LoginResponse /
+	// SyncResponse and exposed via the daemon's Status / SubscribeStatus RPC
+	// so the UI can show remaining time without itself talking to mgm.
+	sessionExpiresAt      time.Time
 	nsGroupStates         []NSGroupState
 	resolvedDomainsStates map[domain.Domain]ResolvedDomainInfo
 	lazyConnectionEnabled bool
@@ -739,6 +745,31 @@ func (d *Status) UpdateLocalPeerState(localPeerState LocalPeerState) {
 	d.notifyStateChange()
 }
 
+// SetSessionExpiresAt records the absolute UTC instant at which the peer's
+// SSO session is set to expire. Pass the zero value to clear (e.g. when the
+// management server stops publishing a deadline because login expiration was
+// disabled or the peer is not SSO-tracked). Same-value updates are no-ops;
+// real changes fan out via notifyStateChange so SubscribeStatus consumers
+// pick up the new deadline on their next read.
+func (d *Status) SetSessionExpiresAt(deadline time.Time) {
+	d.mux.Lock()
+	if d.sessionExpiresAt.Equal(deadline) {
+		d.mux.Unlock()
+		return
+	}
+	d.sessionExpiresAt = deadline
+	d.mux.Unlock()
+	d.notifyStateChange()
+}
+
+// GetSessionExpiresAt returns the most recently recorded SSO session deadline,
+// or the zero value when no deadline is tracked.
+func (d *Status) GetSessionExpiresAt() time.Time {
+	d.mux.Lock()
+	defer d.mux.Unlock()
+	return d.sessionExpiresAt
+}
+
 // AddLocalPeerStateRoute adds a route to the local peer state
 func (d *Status) AddLocalPeerStateRoute(route string, resourceId route.ResID) {
 	d.mux.Lock()