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think really hard

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This commit is contained in:
JackDoan
2026-02-19 14:55:49 -06:00
parent 064153f0c2
commit 8f1d384eb8
1 changed files with 11 additions and 28 deletions
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39
firewall.go
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@@ -353,7 +353,6 @@ func (f *Firewall) SetSNATAddressFromInterface(i *Interface) {
//todo should snatted conntracks get expired out? Probably not needed until if/when we allow reload
f.snatAddr = i.inside.SNATAddress().Addr()
f.unsafeIPv4Origin = i.inside.UnsafeIPv4OriginAddress().Addr()
//f.routableNetworks.Insert(i.inside.UnsafeIPv4OriginAddress()) //todo is this the right idea?
}
func (f *Firewall) ShouldUnSNAT(fp *firewall.Packet) bool {
@@ -525,6 +524,9 @@ func (f *Firewall) applySnat(data []byte, fp *firewall.Packet, c *conn, hostinfo
if !f.snatAddr.IsValid() {
return ErrCannotSNAT
}
if f.snatAddr == fp.LocalAddr { //a packet that came from UDP (incoming) should never ever have our snat address on it
return ErrSNATIdentityMismatch
}
if c.snat.Valid() {
//old flow: make sure it came from the right place
if !slices.Contains(hostinfo.vpnAddrs, c.snat.SrcVpnIp) {
@@ -562,7 +564,6 @@ func (f *Firewall) identifyRemoteNetworkType(h *HostInfo, fp firewall.Packet) Ne
return NetworkTypeVPN
} //else, fallthrough
} else if nwType, ok := h.networks.Lookup(fp.RemoteAddr); ok {
//todo check for if fp.RemoteAddr is our f.snatAddr here too? Does that need a special case?
return nwType //will return NetworkTypeVPN or NetworkTypeUnsafe
}
@@ -581,7 +582,7 @@ func (f *Firewall) allowRemoteNetworkType(nwType NetworkType, fp firewall.Packet
case NetworkTypeInvalidPeer:
return ErrInvalidRemoteIP
case NetworkTypeVPNPeer:
//todo we might need a specialSnatMode case in here to handle routers with v4 addresses when we don't also have a v4 address?
//one day we might need a specialSnatMode case in here to handle routers with v4 addresses when we don't also have a v4 address?
return ErrPeerRejected // reject for now, one day this may have different FW rules
case NetworkTypeUnsafe:
return nil // nothing special, one day this may have different FW rules
@@ -589,8 +590,11 @@ func (f *Firewall) allowRemoteNetworkType(nwType NetworkType, fp firewall.Packet
if f.unsafeIPv4Origin.IsValid() && fp.LocalAddr == f.unsafeIPv4Origin {
return nil //the client case
}
if f.snatAddr.IsValid() { //todo
return nil //todo is this enough?
if f.snatAddr.IsValid() {
if fp.RemoteAddr == f.snatAddr {
return ErrInvalidRemoteIP //we should never get a packet with our SNAT addr as the destination, or "from" our SNAT addr
}
return nil
} else {
return ErrInvalidRemoteIP
}
@@ -603,35 +607,14 @@ func (f *Firewall) willingToHandleLocalAddr(incoming bool, fp firewall.Packet, r
if f.routableNetworks.Contains(fp.LocalAddr) {
return nil //easy, this should handle NetworkTypeVPN in all cases, and NetworkTypeUnsafe on the router side
}
if incoming { //at least for now, reject all traffic other than what we've already decided is routable
if incoming { //at least for now, reject all traffic other than what we've already decided is locally routable
return ErrInvalidLocalIP
}
//now, all traffic is outgoing. Outgoing traffic to these types is not required to be considered inbound-routable
//todo is this right??? can/should these rules be tighter?
//below this line, all traffic is outgoing. Outgoing traffic to NetworkTypeUnsafe is not required to be considered inbound-routable
if remoteNwType == NetworkTypeUnsafe {
return nil
}
//if remoteNwType == NetworkTypeUncheckedSNATPeer {
// return nil
//}
//todo
////watch out, when incoming, this function decides if we will deliver a packet locally
////when outgoing, much less important, it just decides if we're willing to tx
//switch remoteNwType {
//// we never want to accept unconntracked inbound traffic from these network types, but outbound is okay.
//// It's the recipient's job to validate and accept or deny the packet.
//case NetworkTypeUncheckedSNATPeer, NetworkTypeUnsafe:
// //NetworkTypeUnsafe needed here to allow inbound from an unsafe-router
// if incoming {
// return ErrInvalidLocalIP
// }
// return nil
//default:
// return ErrInvalidLocalIP
//}
return ErrInvalidLocalIP
}