tun: windows: set event before waiting
In 097af6e
("tun: windows: protect reads from closing") we made sure no
functions are running when End() is called, to avoid a UaF. But we still
need to kick that event somehow, so that Read() is allowed to exit, in
order to release the lock. So this commit calls SetEvent, while moving
the closing boolean to be atomic so it can be modified without locks,
and then moves to a WaitGroup for the RCU-like pattern.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
parent
db733ccd65
commit
69b39db0b4
@ -40,10 +40,10 @@ type NativeTun struct {
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session wintun.Session
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readWait windows.Handle
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events chan Event
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closing sync.RWMutex
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running sync.WaitGroup
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closeOnce sync.Once
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close int32
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forcedMTU int
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close bool
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}
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var WintunPool, _ = wintun.MakePool("WireGuard")
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@ -111,9 +111,9 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
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}
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func (tun *NativeTun) Name() (string, error) {
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tun.closing.RLock()
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defer tun.closing.RUnlock()
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if tun.close {
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tun.running.Add(1)
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defer tun.running.Done()
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if atomic.LoadInt32(&tun.close) == 1 {
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return "", os.ErrClosed
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}
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return tun.wt.Name()
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@ -130,9 +130,9 @@ func (tun *NativeTun) Events() chan Event {
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func (tun *NativeTun) Close() error {
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var err error
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tun.closeOnce.Do(func() {
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tun.closing.Lock()
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defer tun.closing.Unlock()
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tun.close = true
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atomic.StoreInt32(&tun.close, 1)
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windows.SetEvent(tun.readWait)
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tun.running.Wait()
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tun.session.End()
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if tun.wt != nil {
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_, err = tun.wt.Delete(false)
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@ -158,16 +158,16 @@ func (tun *NativeTun) ForceMTU(mtu int) {
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// Note: Read() and Write() assume the caller comes only from a single thread; there's no locking.
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func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
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tun.closing.RLock()
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defer tun.closing.RUnlock()
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tun.running.Add(1)
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defer tun.running.Done()
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retry:
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if tun.close {
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if atomic.LoadInt32(&tun.close) == 1 {
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return 0, os.ErrClosed
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}
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start := nanotime()
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shouldSpin := atomic.LoadUint64(&tun.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&tun.rate.nextStartTime)) <= rateMeasurementGranularity*2
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for {
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if tun.close {
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if atomic.LoadInt32(&tun.close) == 1 {
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return 0, os.ErrClosed
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}
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packet, err := tun.session.ReceivePacket()
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@ -199,9 +199,9 @@ func (tun *NativeTun) Flush() error {
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}
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func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
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tun.closing.RLock()
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defer tun.closing.RUnlock()
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if tun.close {
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tun.running.Add(1)
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defer tun.running.Done()
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if atomic.LoadInt32(&tun.close) == 1 {
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return 0, os.ErrClosed
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}
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@ -225,9 +225,9 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
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// LUID returns Windows interface instance ID.
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func (tun *NativeTun) LUID() uint64 {
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tun.closing.RLock()
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defer tun.closing.RUnlock()
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if tun.close {
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tun.running.Add(1)
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defer tun.running.Done()
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if atomic.LoadInt32(&tun.close) == 1 {
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return 0
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}
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return tun.wt.LUID()
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