On Windows, the idiomatic way to check access on a named pipe is for
the server to impersonate the client on its current OS thread, perform
access checks using the client's access token, and then revert the OS
thread's access token back to its true self.
The access token is a better representation of the client's rights than just
a username/userid check, as it represents the client's effective rights
at connection time, which might differ from their normal rights.
This patch updates safesocket to do the aforementioned impersonation,
extract the token handle, and then revert the impersonation. We retain
the token handle for the remaining duration of the connection (the token
continues to be valid even after we have reverted back to self).
Since the token is a property of the connection, I changed ipnauth to wrap
the concrete net.Conn to include the token. I then plumbed that change
through ipnlocal, ipnserver, and localapi as necessary.
I also added a PermitLocalAdmin flag to the localapi Handler which I intend
to use for controlling access to a few new localapi endpoints intended
for configuring auto-update.
Updates https://github.com/tailscale/tailscale/issues/755
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Our build system caches files locally and only updates them when something
changes. Since I need to integrate some distsign stuff into the build system
to validate our Windows 7 MSIs, I want to be able to check the cached copy
of a package before downloading a fresh copy from pkgs.
If the signature changes, then obviously the local copy is outdated and we
return an error, at which point we call Download to refresh the package.
Updates https://github.com/tailscale/corp/issues/14334
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
It's very common for OOM crashes on Windows to be caused by lack of page
file space (the NT kernel does not overcommit). Since Windows automatically
manages page file space by default, unless the machine is out of disk space,
this is typically caused by manual page file configurations that are too
small.
This patch obtains the current page file size, the amount of free page file
space, and also determines whether the page file is automatically or manually
managed.
Fixes#9090
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The Windows Security Center is a component that manages the registration of
security products on a Windows system. Only products that have obtained a
special cert from Microsoft may register themselves using the WSC API.
Practically speaking, most vendors do in fact sign up for the program as it
enhances their legitimacy.
From our perspective, this is useful because it gives us a high-signal
source of information to query for the security products installed on the
system. I've tied this query into the osdiag package and is run during
bugreports.
It uses COM bindings that were automatically generated by my prototype
metadata processor, however that program still has a few bugs, so I had
to make a few manual tweaks. I dropped those binding into an internal
package because (for the moment, at least) they are effectively
purpose-built for the osdiag use case.
We also update the wingoes dependency to pick up BSTR.
Fixes#10646
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
In order for the installer to restart the GUI correctly post-upgrade, we
need the GUI to be able to register its restart preferences.
This PR adds API support for doing so. I'm adding it to OSS so that it
is available should we need to do any such registrations on OSS binaries
in the future.
Updates https://github.com/tailscale/corp/issues/13998
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The Layered Service Provider (LSP) is a deprecated (but still supported)
mechanism for inserting user-mode DLLs into a filter chain between the
Winsock API surface (ie, ws2_32.dll) and the internal user-mode interface
to the networking stack.
While their use is becoming more rare due to the aforementioned deprecation,
it is still possible for third-party software to install their DLLs into
this filter chain and interfere with Winsock API calls. Knowing whether
this is happening is useful for troubleshooting.
Fixes https://github.com/tailscale/tailscale/issues/8142
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
* We update wingoes to pick up new version information functionality
(See pe/version.go in the https://github.com/dblohm7/wingoes repo);
* We move the existing LogSupportInfo code (including necessary syscall
stubs) out of util/winutil into a new package, util/osdiag, and implement
the public LogSupportInfo function may be implemented for other platforms
as needed;
* We add a new reason argument to LogSupportInfo and wire that into
localapi's bugreport implementation;
* We add module information to the Windows implementation of LogSupportInfo
when reason indicates a bugreport. We enumerate all loaded modules in our
process, and for each one we gather debug, authenticode signature, and
version information.
Fixes#7802
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Previously, tailscale upgrade was doing the bare minimum for checking
authenticode signatures via `WinVerifyTrustEx`. This is fine, but we can do
better:
* WinVerifyTrustEx verifies that the binary's signature is valid, but it doesn't
determine *whose* signature is valid; tailscale upgrade should also ensure that
the binary is actually signed *by us*.
* I added the ability to check the signatures of MSI files.
* In future PRs I will be adding diagnostic logging that lists details about
every module (ie, DLL) loaded into our process. As part of that metadata, I
want to be able to extract information about who signed the binaries.
This code is modelled on some C++ I wrote for Firefox back in the day. See
https://searchfox.org/mozilla-central/rev/27e4816536c891d85d63695025f2549fd7976392/toolkit/xre/dllservices/mozglue/Authenticode.cpp
for reference.
Fixes#8284
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
In order to improve our ability to understand the state of policies and
registry settings when troubleshooting, we enumerate all values in all subkeys.
x/sys/windows does not already offer this, so we need to call RegEnumValue
directly.
For now we're just logging this during startup, however in a future PR I plan to
also trigger this code during a bugreport. I also want to log more than just
registry.
Fixes#8141
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
I realized that a lot of the problems that we're seeing around migration and
LocalBackend state can be avoided if we drive Windows pref migration entirely
from within tailscaled. By doing it this way, tailscaled can automatically
perform the migration as soon as the connection with the client frontend is
established.
Since tailscaled is already running as LocalSystem, it already has access to
the user's local AppData directory. The profile manager already knows which
user is connected, so we simply need to resolve the user's prefs file and read
it from there.
Of course, to properly migrate this information we need to also check system
policies. I moved a bunch of policy resolution code out of the GUI and into
a new package in util/winutil/policy.
Updates #7626
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
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>
Given recent changes in corp, I originally thought we could remove all of the
syso files, but then I realized that we still need them so that binaries built
purely from OSS (without going through corp) will still receive a manifest.
We can remove the arm32 one though, since we don't support 32-bit ARM on Windows.
Updates https://github.com/tailscale/corp/issues/9576
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We change our invocations of GetExtendedTcpTable to request additional
information about the "module" responsible for the port. In addition to pid,
this output also includes sufficient metadata to enable Windows to resolve
process names and disambiguate svchost processes.
We store the OS-specific output in an OSMetadata field in netstat.Entry, which
portlist may then use as necessary to actually resolve the process/module name.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We've been doing a hard kill of the subprocess, which is only safe as long as
both the cli and gui are not running and the subprocess has had the opportunity
to clean up DNS settings etc. If unattended mode is turned on, this is definitely
unsafe.
I changed babysitProc to close the subprocess's stdin to make it shut down, and
then I plumbed a cancel function into the stdin reader on the subprocess side.
Fixes https://github.com/tailscale/corp/issues/5621
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
WinTun is installed lazily by tailscaled while it is running as LocalSystem.
Based upon what we're seeing in bug reports and support requests, removing
WinTun as a lesser user may fail under certain Windows versions, even when that
user is an Administrator.
By adding a user-defined command code to tailscaled, we can ask the service to
do the removal on our behalf while it is still running as LocalSystem.
* The uninstall code is basically the same as it is in corp;
* The command code will be sent as a service control request and is protected by
the SERVICE_USER_DEFINED_CONTROL access right, which requires Administrator.
I'll be adding follow-up patches in corp to engage this functionality.
Updates https://github.com/tailscale/tailscale/issues/6433
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We want users to have the freedom to start tailscaled with `-no-logs-no-support`,
but that is obviously in direct conflict with tailnets that have network logging
enabled.
When we detect that condition, we record the issue in health, notify the client,
set WantRunning=false, and bail.
We clear the item in health when a profile switch occurs, since it is a
per-tailnet condition that should not propagate across profiles.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
I added util/winutil/LookupPseudoUser, which essentially consists of the bits
that I am in the process of adding to Go's standard library.
We check the provided SID for "S-1-5-x" where 17 <= x <= 20 (which are the
known pseudo-users) and then manually populate a os/user.User struct with
the correct information.
Fixes https://github.com/tailscale/tailscale/issues/869
Fixes https://github.com/tailscale/tailscale/issues/2894
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This patch removes the crappy, half-backed COM initialization used by `go-ole`
and replaces that with the `StartRuntime` function from `wingoes`, a library I
have started which, among other things, initializes COM properly.
In particular, we should always be initializing COM to use the multithreaded
apartment. Every single OS thread in the process becomes implicitly initialized
as part of the MTA, so we do not need to concern ourselves as to whether or not
any particular OS thread has initialized COM. Furthermore, we no longer need to
lock the OS thread when calling methods on COM interfaces.
Single-threaded apartments are designed solely for working with Win32 threads
that have a message pump; any other use of the STA is invalid.
Fixes https://github.com/tailscale/tailscale/issues/3137
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Numerous issues have been filed concerning an inability to install and run
Tailscale headlessly in unattended mode, particularly after rebooting. The
server mode `Prefs` stored in `server-state.conf` were not being updated with
`Persist` state once the node had been succesfully logged in.
Users have been working around this by finagling with the GUI to make it force
a state rewrite. This patch makes that unnecessary by ensuring the required
server mode state is updated when prefs are updated by the control client.
Fixes https://github.com/tailscale/tailscale/issues/3186
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Intermittently in the wild we are seeing failures when calling
`INetworkConnection::GetNetwork`. It is unclear what the root cause is, but what
is clear is that the error is happening inside the object's `IDispatch` invoker
(as opposed to the method implementation itself).
This patch replaces our wrapper for `INetworkConnection::GetNetwork` with an
alternate implementation that directly invokes the method, instead of using
`IDispatch`. I also replaced the implementations of `INetwork::SetCategory` and
`INetwork::GetCategory` while I was there.
This patch is speculative and tightly-scoped so that we could possibly add it
to a dot-release if necessary.
Updates https://github.com/tailscale/tailscale/issues/4134
Updates https://github.com/tailscale/tailscale/issues/6037
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
I added new functions to winutil to obtain the state of a service and all
its depedencies, serialize them to JSON, and write them to a Logf.
When tstun.New returns a wrapped ERROR_DEVICE_NOT_AVAILABLE, we know that wintun
installation failed. We then log the service graph rooted at "NetSetupSvc".
We are interested in that specific service because network devices will not
install if that service is not running.
Updates https://github.com/tailscale/tailscale/issues/5531
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We're adding two log IDs to facilitate data-plane audit logging: a node-specific
log ID, and a domain-specific log ID.
Updated util/deephash/deephash_test.go with revised expectations for tailcfg.Node.
Updates https://github.com/tailscale/corp/issues/6991
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We're going to want to enable audit logging on a per-Tailnet basis. When this
happens, we want control to inform the Tailnet's clients of this capability.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The definition of winHTTPProxyInfo was using the wrong type (uint16 vs uint32)
for its first field. I fixed that type.
Furthermore, any UTF16 strings returned in that structure must be explicitly
freed. I added code to do this.
Finally, since this is the second time I've seen type safety errors in this code,
I switched the native API calls over to use wrappers generated by mkwinsyscall.
I know that would not have helped prevent the previous two problems, but every
bit helps IMHO.
Updates https://github.com/tailscale/tailscale/issues/4811
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
As discussed in previous PRs, we can register for notifications when group
policies are updated and act accordingly.
This patch changes nrptRuleDatabase to receive notifications that group policy
has changed and automatically move our NRPT rules between the local and
group policy subkeys as needed.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
When there are group policy entries for the NRPT that do not belong to Tailscale,
we recognize that we need to add ourselves to group policy and use that registry
key instead of the local one. We also refresh the group policy settings as
necessary to ensure that our changes take effect immediately.
Fixes https://github.com/tailscale/tailscale/issues/4607
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
AFAICT this isn't documented on MSDN, but based on the issue referenced below,
NRPT rules are not working when a rule specifies > 50 domains.
This patch modifies our NRPT rule generator to split the list of domains
into chunks as necessary, and write a separate rule for each chunk.
For compatibility reasons, we continue to use the hard-coded rule ID, but
as additional rules are required, we generate new GUIDs. Those GUIDs are
stored under the Tailscale registry path so that we know which rules are ours.
I made some changes to winutils to add additional helper functions in support
of both the code and its test: I added additional registry accessors, and also
moved some token accessors from paths to util/winutil.
Fixes https://github.com/tailscale/coral/issues/63
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
I wrote this code way back at the beginning of my tenure at Tailscale when we
had concerns about needing to restore deleted machine keys from backups.
We never ended up using this functionality, and the code is now getting in the
way, so we might as well remove it.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Once a stop request is received and the service updates its status to `svc.StopPending`,
it should continue running *until the shutdown sequence is complete*, and then
return out of `(*ipnService).Execute`, which automatically sends a `svc.Stopped`
notification to Windows.
To make this happen, I changed the loop so that it runs until `doneCh` is
closed, and then returns. I also removed a spurious `svc.StopPending` notification
that the Windows Service Control Manager might be interpreting as a request for
more time to shut down.
Finally, I added some optional logging that sends a record of service notifications
to the Windows event log, allowing us to more easily correlate with any Service
Control Manager errors that are sent to the same log.
Change-Id: I5b596122e5e89c4c655fe747a612a52cb4e8f1e0
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We need to be able to provide the ability for the GUI clients to resolve and set
the exit node IP from an untrusted string, thus enabling the ability to specify
that information via enterprise policy.
This patch moves the relevant code out of the handler for `tailscale up`,
into a method on `Prefs` that may then be called by GUI clients.
We also update tests accordingly.
Updates https://github.com/tailscale/corp/issues/4239
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
The MSI installer sets a special sentinel value that we can use to detect it.
I also removed the code that bails out when the installation path is not
`Program Files`, as both the NSIS and MSI installers permit the user to install
to a different path.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
It makes the most sense to have all our utility functions reside in one place.
There was nothing in corp that could not reasonably live in OSS.
I also updated `StartProcessAsChild` to no longer depend on `futureexec`,
thus reducing the amount of code that needed migration. I tested this change
with `tswin` and it is working correctly.
I have a follow-up PR to remove the corresponding code from corp.
The migrated code was mostly written by @alexbrainman.
Sourced from corp revision 03e90cfcc4dd7b8bc9b25eb13a26ec3a24ae0ef9
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This patch adds new functions to be used when accessing system policies,
and revises callers to use the new functions. They first attempt the new
registry path for policies, and if that fails, attempt to fall back to the
legacy path.
We keep non-policy variants of these functions because we should be able to
retain the ability to read settings from locations that are not exposed to
sysadmins for group policy edits.
The remaining changes will be done in corp.
Updates https://github.com/tailscale/tailscale/issues/3584
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Our current workaround made the user check too lax, thus allowing deleted
users. This patch adds a helper function to winutil that checks that the
uid's SID represents a valid Windows security principal.
Now if `lookupUserFromID` determines that the SID is invalid, we simply
propagate the error.
Updates https://github.com/tailscale/tailscale/issues/869
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We replace the cmd.exe invocation with RtlGetNtVersionNumbers for the first
three fields. On Windows 10+, we query for the fourth field which is available
via the registry.
The fourth field is not really documented anywhere; Firefox has been querying
it successfully since Windows 10 was released, so we can be pretty confident in
its longevity at this point.
Fixes https://github.com/tailscale/tailscale/issues/1478
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
utils/winutil/vss contains just enough COM wrapping to query the Volume Shadow Copy service for snapshots.
WalkSnapshotsForLegacyStateDir is the friendlier interface that adds awareness of our actual use case,
mapping the snapshots and locating our legacy state directory.
Updates #3011
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Moving this information into a centralized place so that it is accessible to
code in subsequent commits.
Updates #3011
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This feature wasn't working until I realized that we also need to opt into
the events. MSDN wasn't so generous as to make this easy to deduce.
Updates #2956
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
For the service, all we need to do is handle the `svc.SessionChange` command.
Upon receipt of a `windows.WTS_SESSION_UNLOCK` event, we fire off a goroutine to flush the DNS cache.
(Windows expects responses to service requests to be quick, so we don't want to do that synchronously.)
This is gated on an integral registry value named `FlushDNSOnSessionUnlock`,
whose value we obtain during service initialization.
(See [this link](https://docs.microsoft.com/en-us/windows/win32/api/winsvc/nc-winsvc-lphandler_function_ex) for information re: handling `SERVICE_CONTROL_SESSIONCHANGE`.)
Fixes#2956
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This helper allows us to retrieve `DWORD` and `QWORD` values from the Tailscale key in the Windows registry.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
We unconditionally set appropriate perms on the statefile dir.
We look at the basename of the statefile dir, and if it is "tailscale", then
we set perms as appropriate.
Fixes#2925
Updates #2856
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
ProgramData has a permissive ACL. For us to safely store machine-wide
state information, we must set a more restrictive ACL on our state directory.
We set the ACL so that only talescaled's user (ie, LocalSystem) and the
Administrators group may access our directory.
We must include Administrators to ensure that logs continue to be easily
accessible; omitting that group would force users to use special tools to
log in interactively as LocalSystem, which is not ideal.
(Note that the ACL we apply matches the ACL that was used for LocalSystem's
AppData\Local).
There are two cases where we need to reset perms: One is during migration
from the old location to the new. The second case is for clean installations
where we are creating the file store for the first time.
Updates #2856
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
Aaron Klotz
