GetMessage can call back into Go, triggering stack growth and causing the stack
to be copied to a new memory region, which invalidates the original stack pointer
passed to the syscall. Since GetMessage uses that pointer to write the message
before returning, this leads to memory corruption.
In this PR, we fix this by using runtime.Pinner, which requires the pointer to refer
to heap-allocated memory.
Fixes#19263Fixes#17832
Signed-off-by: Nick Khyl <nickk@tailscale.com>
This file was never truly necessary and has never actually been used in
the history of Tailscale's open source releases.
A Brief History of AUTHORS files
---
The AUTHORS file was a pattern developed at Google, originally for
Chromium, then adopted by Go and a bunch of other projects. The problem
was that Chromium originally had a copyright line only recognizing
Google as the copyright holder. Because Google (and most open source
projects) do not require copyright assignemnt for contributions, each
contributor maintains their copyright. Some large corporate contributors
then tried to add their own name to the copyright line in the LICENSE
file or in file headers. This quickly becomes unwieldy, and puts a
tremendous burden on anyone building on top of Chromium, since the
license requires that they keep all copyright lines intact.
The compromise was to create an AUTHORS file that would list all of the
copyright holders. The LICENSE file and source file headers would then
include that list by reference, listing the copyright holder as "The
Chromium Authors".
This also become cumbersome to simply keep the file up to date with a
high rate of new contributors. Plus it's not always obvious who the
copyright holder is. Sometimes it is the individual making the
contribution, but many times it may be their employer. There is no way
for the proejct maintainer to know.
Eventually, Google changed their policy to no longer recommend trying to
keep the AUTHORS file up to date proactively, and instead to only add to
it when requested: https://opensource.google/docs/releasing/authors.
They are also clear that:
> Adding contributors to the AUTHORS file is entirely within the
> project's discretion and has no implications for copyright ownership.
It was primarily added to appease a small number of large contributors
that insisted that they be recognized as copyright holders (which was
entirely their right to do). But it's not truly necessary, and not even
the most accurate way of identifying contributors and/or copyright
holders.
In practice, we've never added anyone to our AUTHORS file. It only lists
Tailscale, so it's not really serving any purpose. It also causes
confusion because Tailscalars put the "Tailscale Inc & AUTHORS" header
in other open source repos which don't actually have an AUTHORS file, so
it's ambiguous what that means.
Instead, we just acknowledge that the contributors to Tailscale (whoever
they are) are copyright holders for their individual contributions. We
also have the benefit of using the DCO (developercertificate.org) which
provides some additional certification of their right to make the
contribution.
The source file changes were purely mechanical with:
git ls-files | xargs sed -i -e 's/\(Tailscale Inc &\) AUTHORS/\1 contributors/g'
Updates #cleanup
Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>
[G,S]etWindowLongPtrW are not available on 32-bit Windows, where [G,S]etWindowLongW should be used instead.
The initial revision of #14945 imported the win package for calling and other Win32 API functions, which exported
the correct API depending on the platform. However, the same logic wasn't implemented when we removed
the win package dependency in a later revision, resulting in panics on Windows 10 x86 (there's no 32-bit Windows 11).
In this PR, we update the ipn/desktop package to use either [G,S]etWindowLongPtrW or [G,S]etWindowLongW
depending on the platform.
Fixes#15684
Signed-off-by: Nick Khyl <nickk@tailscale.com>
In this PR, we enable the registration of LocalBackend extensions to exclude code specific to certain
platforms or environments. We then introduce desktopSessionsExt, which is included only in Windows builds
and only if the ts_omit_desktop_sessions tag is disabled for the build. This extension tracks desktop sessions
and switches to (or remains on) the appropriate profile when a user signs in or out, locks their screen,
or disconnects a remote session.
As desktopSessionsExt requires an ipn/desktop.SessionManager, we register it with tsd.System
for the tailscaled subprocess on Windows.
We also fix a bug in the sessionWatcher implementation where it attempts to close a nil channel on stop.
Updates #14823
Updates tailscale/corp#26247
Signed-off-by: Nick Khyl <nickk@tailscale.com>
This PR adds a new package, ipn/desktop, which provides a platform-agnostic
interface for enumerating desktop sessions and registering session callbacks.
Currently, it is implemented only for Windows.
Updates #14823
Signed-off-by: Nick Khyl <nickk@tailscale.com>
Nick Khyl
Will Norris