These new helpers make the code a lot cleaner. I confirmed that the
simple helpers like `atomic.Int64` don't add any extra overhead as they
get inlined by the compiler. `atomic.Pointer` adds an extra method call
as it no longer gets inlined, but we aren't using these on the hot path
so it is probably okay.
By default, Nebula replies to packets it has no tunnel for with a `recv_error` packet. This packet helps speed up re-connection
in the case that Nebula on either side did not shut down cleanly. This response can be abused as a way to discover if Nebula is running
on a host though. This option lets you configure if you want to send `recv_error` packets always, never, or only to private network remotes.
valid values: always, never, private
This setting is reloadable with SIGHUP.
We are currently testing changes for multiport (related to #497) that
use fields 6 and 7 in the protobuf. Reserved these fields so that when
we eventually open the PR we are backwards compatible with any future
changes.
* fix panic in handleInvalidCertificate
when HandleMonitorTick fires, the hostmap can be nil which causes a panic to occur when trying to clean up the hostmap in handleInvalidCertificate. This fix just stops the invalidation from continuing if the hostmap doesn't exist.
* removed conditional for disconnectInvalid in HandleDeletionTick
This restores the hostMap.QueryVpnIP block to how it looked before #370
was merged. I'm not sure why the patch from #370 wanted to continue on
if there was no match found in the hostmap, since there isn't anything
to do at that point (the tunnel has already been closed).
This was causing a crash because the handleInvalidCertificate check
expects the hostinfo to be passed in (but it is nil since there was no
hostinfo in the hostmap).
Fixes: #657
With Nebula 1.4.0, if you create an unsafe_route that has a collision with an existing route on the system, the unsafe_route will be silently dropped (and the existing system route remains).
With Nebula 1.5.0, this same situation will cause Nebula to fail to start with an error (EEXIST).
This change restores the Nebula 1.4.0 behavior (but with a WARN log as well).
With the previous implementation, we check if route.MTU is greater than zero,
but it will always be because we set it to the default MTU in
parseUnsafeRoutes. This change leaves it as zero in parseUnsafeRoutes so
it can be examined later.
* don't set ConnectionState to nil
We might have packets processing in another thread, so we can't safely
just set this to nil. Since we removed it from the hostmaps, the next
packets to process should start the handshake over again.
I believe this comment is outdated or incorrect, since the next
handshake will start over with a new HostInfo, I don't think there is
any way a counter reuse could happen:
> We must null the connectionstate or a counter reuse may happen
Here is a panic we saw that I think is related:
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x93a037]
goroutine 59 [running, locked to thread]:
github.com/slackhq/nebula.(*Firewall).Drop(...)
github.com/slackhq/nebula/firewall.go:380
github.com/slackhq/nebula.(*Interface).consumeInsidePacket(...)
github.com/slackhq/nebula/inside.go:59
github.com/slackhq/nebula.(*Interface).listenIn(...)
github.com/slackhq/nebula/interface.go:233
created by github.com/slackhq/nebula.(*Interface).run
github.com/slackhq/nebula/interface.go:191
* use closeTunnel
> Version v0.0.0-20211202192323-5770296d904e of golang.org/x/crypto fixes a vulnerability in the golang.org/x/crypto/ssh package which allowed unauthenticated clients to cause a panic in SSH servers.
>
> This issue was discovered and reported by Rod Hynes, Psiphon Inc., and is tracked as CVE-2021-43565 and Issue golang/go#49932.
Updated golang.org/x/crypto 089bfa5675...5770296d90
Updated golang.org/x/net 4a448f8816...69e39bad7d
When running in `-test` mode, `tun` is set to nil. So we should move the
defer into the `!configTest` if block.
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x54855c]
goroutine 1 [running]:
github.com/slackhq/nebula.Main.func3(0x4000135e80, {0x0, 0x0})
github.com/slackhq/nebula/main.go:176 +0x2c
github.com/slackhq/nebula.Main(0x400022e060, 0x1, {0x76faa0, 0x5}, 0x4000230000, 0x0)
github.com/slackhq/nebula/main.go:316 +0x2414
main.main()
github.com/slackhq/nebula/cmd/nebula/main.go:54 +0x540
Without these comments, gofmt 1.16.9 will complain. Since we otherwise
still support building with go1.16, lets add the comments to make it
easier to compile and gofmt.
Related: #588
