AFAICT this was always present, the log read mid-execution was never safe.
But it seems like the recent magicsock refactoring made the race much
more likely.
Signed-off-by: David Anderson <danderson@tailscale.com>
Reported on IRC: in an edge case, you can end up with a directManager DNS
manager and --accept-dns=false, in which case we should do nothing, but
actually end up restarting resolved whenever the netmap changes, even though
the user told us to not manage DNS.
Signed-off-by: David Anderson <danderson@tailscale.com>
Reported on IRC: a resolv.conf that contained two entries for
"nameserver 127.0.0.53", which defeated our "is resolved actually
in charge" check. Relax that check to allow any number of nameservers,
as long as they're all 127.0.0.53.
Signed-off-by: David Anderson <danderson@tailscale.com>
* Revert "Revert "types/key: add MachinePrivate and MachinePublic.""
This reverts commit 61c3b98a24.
Signed-off-by: David Anderson <danderson@tailscale.com>
* types/key: add ControlPrivate, with custom serialization.
ControlPrivate is just a MachinePrivate that serializes differently
in JSON, to be compatible with how the Tailscale control plane
historically serialized its private key.
Signed-off-by: David Anderson <danderson@tailscale.com>
Plumb throughout the codebase as a replacement for the mixed use of
tailcfg.MachineKey and wgkey.Private/Public.
Signed-off-by: David Anderson <danderson@tailscale.com>
Our code is not vulnerable to the issue in question: it only happens in the decompression
path for untrusted inputs, and we only use xz as part of mkpkg, which is write-only
and operates on trusted build system outputs to construct deb and rpm packages.
Still, it's nice to keep the dependabot dashboard clean.
Signed-off-by: David Anderson <danderson@tailscale.com>
It was useful early in development when disco clients were the
exception and tailscale logs were noisier than today, but now
non-disco is the exception.
Updates #2752
Signed-off-by: David Anderson <danderson@tailscale.com>
Having removed magicconn.Start, there's no need to synchronize startup
of other things to it any more.
Signed-off-by: David Anderson <danderson@tailscale.com>
Over time, other magicsock refactors have made Start effectively a
no-op, except that some other functions choose to panic if called
before Start.
Signed-off-by: David Anderson <danderson@tailscale.com>
We were returning an error almost, but not quite like errConnClosed in
a single codepath, which could still trip the panic on reconfig in the
test logic.
Signed-off-by: David Anderson <danderson@tailscale.com>
Our prod code doesn't eagerly handshake, because our disco layer enables
on-demand handshaking. Configuring both peers to eagerly handshake leads
to WireGuard handshake races that make TestTwoDevicePing flaky.
Signed-off-by: David Anderson <danderson@tailscale.com>
It only existed to override one test-only behavior with a
different test-only behavior, in both cases working around
an annoying feature of our CI environments. Instead, handle
that weirdness entirely in the test code, with a tweaked
TestOnlyPacketListener that gets injected.
Signed-off-by: David Anderson <danderson@tailscale.com>
The docstring said it was meant for use in tests, but it's specifically a
special codepath that is _only_ used in tests, so make the claim stronger.
Signed-off-by: David Anderson <danderson@tailscale.com>
Instead of using the legacy codepath, teach discoEndpoint to handle
peers that have a home DERP, but no disco key. We can still communicate
with them, but only over DERP.
Signed-off-by: David Anderson <danderson@tailscale.com>
Windows 8.1 incorrectly handles search paths on an interface with no
associated resolver, so we have to provide a full primary DNS config
rather than use Windows 8.1's nascent-but-present NRPT functionality.
Fixes#2237.
Signed-off-by: David Anderson <danderson@tailscale.com>
It's possible to install a configuration that passes our current checks
for systemd-resolved, without actually pointing to systemd-resolved. In
that case, we end up programming DNS in resolved, but that config never
applies to any name resolution requests on the system.
This is quite a far-out edge case, but there's a simple additional check
we can do: if the header comment names systemd-resolved, there should be
a single nameserver in resolv.conf pointing to 127.0.0.53. If not, the
configuration should be treated as an unmanaged resolv.conf.
Fixes#2136.
Signed-off-by: David Anderson <danderson@tailscale.com>
The dependency is a "soft" ordering dependency only, meaning that
tailscaled will start after those services if those services were
going to be run anyway, but doesn't force either of them to run.
That's why it's safe to specify this dependency unconditionally,
even for systems that don't run those services.
Updates #2127.
Signed-off-by: David Anderson <danderson@tailscale.com>
DNS names consist of labels, but outside of length limits, DNS
itself permits any content within the labels. Some records require
labels to conform to hostname limitations (which is what we implemented
before), but not all.
Fixes#2024.
Signed-off-by: David Anderson <danderson@tailscale.com>
This leads to a cleaner separation of intent vs. implementation
(Routes is now the only place specifying who handles DNS requests),
and allows for cleaner expression of a configuration that creates
MagicDNS records without serving them to the OS.
Signed-off-by: David Anderson <danderson@tailscale.com>
With this change, shared node names resolve correctly on split DNS-supporting
operating systems.
Fixestailscale/corp#1706
Signed-off-by: David Anderson <danderson@tailscale.com>
NetworkManager fixed the bug that forced us to use NetworkManager
if it's programming systemd-resolved, and in the same release also
made NetworkManager ignore DNS settings provided for unmanaged
interfaces... Which breaks what we used to do. So, with versions
1.26.6 and above, we MUST NOT use NetworkManager to indirectly
program systemd-resolved, but thankfully we can talk to resolved
directly and get the right outcome.
Fixes#1788
Signed-off-by: David Anderson <danderson@tailscale.com>
This used to not be necessary, because MagicDNS always did full proxying.
But with split DNS, we need to know which names to route to our resolver,
otherwise reverse lookups break.
This captures the entire CGNAT range, as well as our Tailscale ULA.
Signed-off-by: David Anderson <danderson@tailscale.com>
