Commit Graph

11 Commits (8085324449c133adf6214f07845df62cac970b30)

Author SHA1 Message Date
Claus Lensbøl 8085324449
net/dns: retrample resolve.conf when another process has trampled it
When using the resolve.conf file for setting DNS, it is possible that
some other services will trample the file and overwrite our set DNS
server. Experiments has shown this to be a racy error depending on how
quickly processes start.

Make an attempt to trample back the file a limited number of times if
the file is changed.

Updates #16635

Signed-off-by: Claus Lensbøl <claus@tailscale.com>
2 days ago
Andrew Dunham 53a5d00fff net/dns: ensure /etc/resolv.conf is world-readable even with a umask
Previously, if we had a umask set (e.g. 0027) that prevented creating a
world-readable file, /etc/resolv.conf would be created without the o+r
bit and thus other users may be unable to resolve DNS.

Since a umask only applies to file creation, chmod the file after
creation and before renaming it to ensure that it has the appropriate
permissions.

Updates #12609

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I2a05d64f4f3a8ee8683a70be17a7da0e70933137
1 year ago
Aaron Klotz 3511d1f8a2 cmd/tailscaled, net/dns, wgengine/router: start Windows child processes with DETACHED_PROCESS when I/O is being piped
When we're starting child processes on Windows that are CLI programs that
don't need to output to a console, we should pass in DETACHED_PROCESS as a
CreationFlag on SysProcAttr. This prevents the OS from even creating a console
for the child (and paying the associated time/space penalty for new conhost
processes). This is more efficient than letting the OS create the console
window and then subsequently trying to hide it, which we were doing at a few
callsites.

Fixes #12270

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2 years ago
Brad Fitzpatrick 745931415c health, all: remove health.Global, finish plumbing health.Tracker
Updates #11874
Updates #4136

Change-Id: I414470f71d90be9889d44c3afd53956d9f26cd61
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Aaron Klotz 9687f3700d net/dns: deal with Windows wsl.exe hangs
Despite the fact that WSL configuration is still disabled by default, we
continue to log the machine's list of WSL distros as a diagnostic measure.

Unfortunately I have seen the "wsl.exe -l" command hang indefinitely. This patch
adds a (more than reasonable) 10s timeout to ensure that tailscaled does not get
stuck while executing this operation.

I also modified the Windows implementation of NewOSConfigurator to do the
logging asynchronously, since that information is not required in order to
continue starting up.

Fixes #7476

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
3 years ago
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
3 years ago
Aaron Klotz f93cf6fa03 net/dns: fix checking for wrapped error when attempting to read wsl.conf for Windows WSL2
Fixes https://github.com/tailscale/tailscale/issues/3437

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
4 years ago
David Anderson 124363e0ca net/dns: detect and decode UTF-16 from wsl.exe earlier.
Fixes #3170

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson a320d70614 net/dns: fall back to copy+delete/truncate if moving to/from /etc/resolv.conf fails.
In some containers, /etc/resolv.conf is a bind-mount from outside the container.
This prevents renaming to or from /etc/resolv.conf, because it's on a different
filesystem from linux's perspective. It also prevents removing /etc/resolv.conf,
because doing so would break the bind-mount.

If we find ourselves within this environment, fall back to using copy+delete when
renaming to /etc/resolv.conf, and copy+truncate when renaming from /etc/resolv.conf.

Fixes #3000

Co-authored-by: Denton Gentry <dgentry@tailscale.com>
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
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>
4 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>
4 years ago