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drop unroutable packets (#267) 

Currently, if a packet arrives on the tun device with a destination that
is not a routable Nebula IP, `queryUnsafeRoute` converts that IP to
0.0.0.0 and we store that packet and try to look up that IP with the
lighthouse. This doesn't make any sense to do, if we get a packet that
is unroutable we should just drop it.

Note, we have a few configurable options like `drop_local_broadcast`
and `drop_multicast` which do this for a few specific types, but since
no packets like this will send correctly I think we should just drop
anything that is unroutable.
This commit is contained in:
Wade Simmons 2020-08-04 22:59:04 -04:00 committed by GitHub
parent a54f3fc681
commit ac557f381b
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 26 additions and 0 deletions
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26
inside.go
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@ -30,6 +30,14 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *FirewallPacket,
}
hostinfo := f.getOrHandshake(fwPacket.RemoteIP)
if hostinfo == nil {
if l.Level >= logrus.DebugLevel {
l.WithField("vpnIp", IntIp(fwPacket.RemoteIP)).
WithField("fwPacket", fwPacket).
Debugln("dropping outbound packet, vpnIp not in our CIDR or in unsafe routes")
}
return
}
ci := hostinfo.ConnectionState
if ci.ready == false {
@ -59,9 +67,13 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *FirewallPacket,
}
}
// getOrHandshake returns nil if the vpnIp is not routable
func (f *Interface) getOrHandshake(vpnIp uint32) *HostInfo {
if f.hostMap.vpnCIDR.Contains(int2ip(vpnIp)) == false {
vpnIp = f.hostMap.queryUnsafeRoute(vpnIp)
if vpnIp == 0 {
return nil
}
}
hostinfo, err := f.hostMap.PromoteBestQueryVpnIP(vpnIp, f)
@ -136,6 +148,13 @@ func (f *Interface) sendMessageNow(t NebulaMessageType, st NebulaMessageSubType,
// SendMessageToVpnIp handles real ip:port lookup and sends to the current best known address for vpnIp
func (f *Interface) SendMessageToVpnIp(t NebulaMessageType, st NebulaMessageSubType, vpnIp uint32, p, nb, out []byte) {
hostInfo := f.getOrHandshake(vpnIp)
if hostInfo == nil {
if l.Level >= logrus.DebugLevel {
l.WithField("vpnIp", IntIp(vpnIp)).
Debugln("dropping SendMessageToVpnIp, vpnIp not in our CIDR or in unsafe routes")
}
return
}
if !hostInfo.ConnectionState.ready {
// Because we might be sending stored packets, lock here to stop new things going to
@ -160,6 +179,13 @@ func (f *Interface) sendMessageToVpnIp(t NebulaMessageType, st NebulaMessageSubT
// SendMessageToAll handles real ip:port lookup and sends to all known addresses for vpnIp
func (f *Interface) SendMessageToAll(t NebulaMessageType, st NebulaMessageSubType, vpnIp uint32, p, nb, out []byte) {
hostInfo := f.getOrHandshake(vpnIp)
if hostInfo == nil {
if l.Level >= logrus.DebugLevel {
l.WithField("vpnIp", IntIp(vpnIp)).
Debugln("dropping SendMessageToAll, vpnIp not in our CIDR or in unsafe routes")
}
return
}
if hostInfo.ConnectionState.ready == false {
// Because we might be sending stored packets, lock here to stop new things going to