Commit Graph

111 Commits (1cedd944cfdb07edab2b3237631639b5bf03d5ed)

Author SHA1 Message Date
David Crawshaw 6b9f8208f4 net/dns: do not run wsl.exe as LocalSystem
It doesn't work. It needs to run as the user.

	https://github.com/microsoft/WSL/issues/4803

The mechanism for doing this was extracted from:

	https://web.archive.org/web/20101009012531/http://blogs.msdn.com/b/winsdk/archive/2009/07/14/launching-an-interactive-process-from-windows-service-in-windows-vista-and-later.aspx

While here, we also reclaculate WSL distro set on SetDNS.
This accounts for:

	1. potential inability to access wsl.exe on startup
	2. WSL being installed while Tailscale is running
	3. A new WSL distrobution being installed

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
David Crawshaw 1147c7fd4f net/dns: set WSL /etc/resolv.conf
We also have to make a one-off change to /etc/wsl.conf to stop every
invocation of wsl.exe clobbering the /etc/resolv.conf. This appears to
be a safe change to make permanently, as even though the resolv.conf is
constantly clobbered, it is always the same stable internal IP that is
set as a nameserver. (I believe the resolv.conf clobbering predates the
MS stub resolver.)

Tested on WSL2, should work for WSL1 too.

Fixes #775

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
David Crawshaw 9b063b86c3 net/dns: factor directManager out over an FS interface
This is preliminary work for using the directManager as
part of a wslManager on windows, where in addition to configuring
windows we'll use wsl.exe to edit the linux file system and modify the
system resolv.conf.

The pinholeFS is a little funky, but it's designed to work through
simple unix tools via wsl.exe without invoking bash. I would not have
thought it would stand on its own like this, but it turns out it's
useful for writing a test for the directManager.

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
julianknodt 72a0b5f042 net/dns/resolver: fmt item
This has been bothering me for a while, but everytime I run format from the root directory
it also formats this file. I didn't want to add it to my other PRs but it's annoying to have to
revert it every time.

Signed-off-by: julianknodt <julianknodt@gmail.com>
3 years ago
David Crawshaw 80b1308974 net/dns: remove ref to managerImpl
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
Adrian Dewhurst bcaae3e074 net/dns/resolver: clamp EDNS size
This change (subject to some limitations) looks for the EDNS OPT record
in queries and responses, clamping the size field to fit within our DNS
receive buffer. If the size field is smaller than the DNS receive buffer
then it is left unchanged.

I think we will eventually need to transition to fully processing the
DNS queries to handle all situations, but this should cover the most
common case.

Mostly fixes #2066

Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
3 years ago
David Anderson 084d48d22d net/dns: always proxy through quad-100 on windows 8.1.
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>
3 years ago
Brad Fitzpatrick 45e64f2e1a net/dns{,/resolver}: refactor DNS forwarder, send out of right link on macOS/iOS
Fixes #2224
Fixes tailscale/corp#2045

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 733d52827b net/dns/resolver: skip test on macOS
Fixes #2229

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
David Crawshaw 297b3d6fa4 staticcheck.conf: turn off noisy lint errors
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
David Anderson 9337826011 net/dns: fix inverted test for NetworkManager version.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 320cc8fa21 net/dns: verify that systemd-resolved is actually in charge.
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>
3 years ago
David Anderson e7164425b3 net/dns: don't use NetworkManager for DNS on very old NetworkManagers.
Fixes #1945.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Dave Anderson 144c68b80b
net/dns: avoid using NetworkManager as much as possible. (#1945)
Addresses #1699 as best as possible.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Adrian Dewhurst 8b11937eaf net/dns/resolver: permit larger max responses, signal truncation
This raises the maximum DNS response message size from 512 to 4095. This
should be large enough for almost all situations that do not need TCP.
We still do not recognize EDNS, so we will still forward requests that
claim support for a larger response size than 4095 (that will be solved
later). For now, when a response comes back that is too large to fit in
our receive buffer, we now set the truncation flag in the DNS header,
which is an improvement from before but will prompt attempts to use TCP
which isn't supported yet.

On Windows, WSARecvFrom into a buffer that's too small returns an error
in addition to the data. On other OSes, the extra data is silently
discarded. In this case, we prefer the latter so need to catch the error
on Windows.

Partially addresses #1123

Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
3 years ago
David Anderson 7fab244614 net/dns/resolver: don't spam logs on EHOSTUNREACH.
Fixes #1719.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson e2dcf63420 net/dns: replace AuthoritativeSuffixes with nil Route entries.
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>
3 years ago
David Anderson 6690f86ef4 net/dns: always offer MagicDNS records at 100.100.100.100.
Fixes #1886.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Josh Bleecher Snyder 25df067dd0 all: adapt to opaque netaddr types
This commit is a mishmash of automated edits using gofmt:

gofmt -r 'netaddr.IPPort{IP: a, Port: b} -> netaddr.IPPortFrom(a, b)' -w .
gofmt -r 'netaddr.IPPrefix{IP: a, Port: b} -> netaddr.IPPrefixFrom(a, b)' -w .

gofmt -r 'a.IP.Is4 -> a.IP().Is4' -w .
gofmt -r 'a.IP.As16 -> a.IP().As16' -w .
gofmt -r 'a.IP.Is6 -> a.IP().Is6' -w .
gofmt -r 'a.IP.As4 -> a.IP().As4' -w .
gofmt -r 'a.IP.String -> a.IP().String' -w .

And regexps:

\w*(.*)\.Port = (.*)  ->  $1 = $1.WithPort($2)
\w*(.*)\.IP = (.*)  ->  $1 = $1.WithIP($2)

And lots of manual fixups.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
David Anderson cfde997699 net/dns: don't use interfaces.Tailscale to find the tailscale interface index.
interfaces.Tailscale only returns an interface if it has at least one Tailscale
IP assigned to it. In the resolved DNS manager, when we're called upon to tear
down DNS config, the interface no longer has IPs.

Instead, look up the interface index on construction and reuse it throughout
the daemon lifecycle.

Fixes #1892.

Signed-off-by: David Anderson <dave@natulte.net>
3 years ago
David Anderson 3c8e230ee1 Revert "net/dns: set IPv4 auto mode in NM, so it lets us set DNS."
This reverts commit 7d16c8228b.

I have no idea how I ended up here. The bug I was fixing with this change
fails to reproduce on Ubuntu 18.04 now, and this change definitely does
break 20.04, 20.10, and Debian Buster. So, until we can reliably reproduce
the problem this was meant to fix, reverting.

Part of #1875

Signed-off-by: David Anderson <dave@natulte.net>
3 years ago
David Anderson 5bd38b10b4 net/dns: log the correct error when NM Reapply fails.
Found while debugging #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 7d16c8228b net/dns: set IPv4 auto mode in NM, so it lets us set DNS.
Part of #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 77e2375501 net/dns: don't try to configure LLMNR or mdns in NetworkManager.
Fixes #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Josh Bleecher Snyder 20e04418ff net/dns: add GOOS build tags
Fixes #1786

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
3 years ago
David Anderson bf9ef1ca27 net/dns: stop NetworkManager breaking v6 connectivity when setting DNS.
Tentative fix for #1699

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 44c2b7dc79 net/dns: on windows, skip site-local v6 resolvers.
Further refinement for tailscale/corp#1662.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 97d2fa2f56 net/dns: work around WSL DNS implementation flaws.
Fixes tailscale/corp#1662

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson f6b7d08aea net/dns: work around new NetworkManager in other selection paths.
Further bits of #1788

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 25ce9885a2 net/dns: don't use NM+resolved for NM >=1.26.6.
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>
3 years ago
David Anderson 30f5d706a1 net/dns/resolver: remove unnecessary/racy WaitGroup.
Fixes #1663

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 89c81c26c5 net/dns: fix resolved match domains when no nameservers are provided.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 4be26b269f net/dns: correctly capture all traffic in non-split configs.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson ca283ac899 net/dns: remove config in openresolv when given an empty DNS config.
Part of #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 53213114ec net/dns: make debian_resolvconf correctly clear DNS configs.
More of #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 3b1ab78954 net/dns: restore resolv.conf when given an empty config in directManager.
Fixes #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson 158328ba24 net/dns: remove ForceSplitDNSForTesting.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
David Anderson bb0710d51d net/dns: add debugging traces to DNS manager selection on linux.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 4b70c7b717 net/dns: fix inverted test for NetworkManager.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 4849a4d3c8 net/dns: error out on linux if /etc/resolv.conf can't be read.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 1f9b73a531 net/dns: fix freebsd DNS manager selection.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
Brad Fitzpatrick c2ca2ac8c4 net/dns: fix FreeBSD build
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
David Anderson 84bd50329a net/dns: fix staticheck.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson d6bb11b5bf net/dns: implement correct manager detection on linux.
Part of #953.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 9ef932517b net/dns: fix NM's GetBaseConfig when no configs exist.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson fe3b1ab747 net/dns: refactor dbus connection setup in resolved manager.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 854d5d36a1 net/dns: return error from NewOSManager, use it to initialize NM.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 9aa33b43e6 net/dns: support split and unsplit DNS in NetworkManager.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 87eb8384f5 net/dns: fix up NetworkManager configurator a bit.
Clear LLMNR and mdns flags, update reasoning for our settings,
and set our override priority harder than before when we want
to be primary resolver.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 3d81e6260b net/dns: set resolved DefaultRoute setting according to split-dns mode.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago