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Two Handhake initiation releated race-conditions fixed #48

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Two Handhake initiation releated race-conditions fixed #48

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d164cb3
An attemt to fix handshakeAttempts atomic counter:
May 20, 2021
425aa97
Do not flood new HandshakeInitiations, if some is already in progress
May 20, 2021
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12 changes: 9 additions & 3 deletions device/send.go
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,7 @@ func (peer *Peer) SendKeepalive() {

func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
if !isRetry {
atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
atomic.StoreUint32(&peer.timers.handshakeAttempts, 1)
}

peer.handshake.mutex.RLock()
Expand Down Expand Up @@ -193,7 +193,10 @@ func (peer *Peer) keepKeyFreshSending() {
}
nonce := atomic.LoadUint64(&keypair.sendNonce)
if nonce > RekeyAfterMessages || (keypair.isInitiator && time.Since(keypair.created) > RekeyAfterTime) {
peer.SendHandshakeInitiation(false)
// Do not send new HandshakeInitiation, if handshake retry is already in progress
if !peer.handshakeInProgress() {
peer.SendHandshakeInitiation(false)
}
}
}

Expand Down Expand Up @@ -298,7 +301,10 @@ top:

keypair := peer.keypairs.Current()
if keypair == nil || atomic.LoadUint64(&keypair.sendNonce) >= RejectAfterMessages || time.Since(keypair.created) >= RejectAfterTime {
peer.SendHandshakeInitiation(false)
// Do not send new HandshakeInitiation, if handshake retry is already in progress
if !peer.handshakeInProgress() {
peer.SendHandshakeInitiation(false)
}
return
}

Expand Down
15 changes: 13 additions & 2 deletions device/timers.go
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,9 @@ func expiredRetransmitHandshake(peer *Peer) {
if atomic.LoadUint32(&peer.timers.handshakeAttempts) > MaxTimerHandshakes {
peer.device.log.Verbosef("%s - Handshake did not complete after %d attempts, giving up", peer, MaxTimerHandshakes+2)

// Reset attempts count
atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)

if peer.timersActive() {
peer.timers.sendKeepalive.Del()
}
Expand All @@ -95,7 +98,7 @@ func expiredRetransmitHandshake(peer *Peer) {
}
} else {
atomic.AddUint32(&peer.timers.handshakeAttempts, 1)
peer.device.log.Verbosef("%s - Handshake did not complete after %d seconds, retrying (try %d)", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
peer.device.log.Verbosef("%s - Handshake did not complete after %d seconds, retrying (try %d)", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts))

/* We clear the endpoint address src address, in case this is the cause of trouble. */
peer.Lock()
Expand Down Expand Up @@ -141,10 +144,18 @@ func expiredPersistentKeepalive(peer *Peer) {
}
}

/* Returns true if HandshakeInitiation is already started (and not yet finished) */
func (peer *Peer) handshakeInProgress() bool {
return atomic.LoadUint32(&peer.timers.handshakeAttempts) > 0
}

/* Should be called after an authenticated data packet is sent. */
func (peer *Peer) timersDataSent() {
if peer.timersActive() && !peer.timers.newHandshake.IsPending() {
peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
// Do not restart handshake because of staled data traffic, if it is already in progress
if !peer.handshakeInProgress() {
peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
}
}
}

Expand Down