All was well with NetSetupAnticipatedInstanceId, until a bug crept into
recent Windows builds that caused old GUIDs not to be properly removed,
resulting in subsequent adapter creations to fail, because NetSetup
AnticipatedInstanceId considers it fatal when the target GUID
already exists, even if in diminished form.
The initial solution was to detect cruft, and then steal a
TrustedInstaller token and sleuth around the registry cleaning things
up. The horror!
Uncomfortable with this, I reopened IDA and had a look around with fresh
eyes, three years after the original discovery of NetSetupAnticipated
InstanceId. There, I found some interesting behavior in
NetSetupSvcDeviceManager::InstallNetworkInterfaces, which amounts to
something like:
if (IsSet("RetiredNetCfgInstanceId") {
if (IsSet("NetSetupAnticipatedInstanceId")
DeleteAdapter(GetValue("RetiredNetCfgInstanceId"));
else
Set("NetSetupAnticipatedInstanceId", GetValue("RetiredNetCfgInstanceId"));
Delete("RetiredNetCfgInstanceId");
}
CreateAdapter = TRUE;
if (IsSet("NetSetupAnticipatedInstanceId")) {
Guid = GetValue("NetSetupAnticipatedInstanceId");
if (AdapterAlreadyExists(Guid))
CreateAdapter = FALSE;
else
SetGuidOfNewAdapter(Guid);
Delete("NetSetupAnticipatedInstanceId");
} else if (IsSet("SuggestedInstanceId")) {
Guid = GetValue("SuggestedInstanceId");
if (!AdapterAlreadyExists(Guid))
SetGuidOfNewAdapter(Guid);
Delete("SuggestedInstanceId");
}
Thus, one appealing strategy would be to set both NetSetupAnticipated
InstanceId and RetiredInstanceId to the same value, and let the service
handle deleting the old one for us before creating the new one.
However, the cleanup of the old adapter winds up being quasi-
asynchronous, and thus we still wind up in the CreateAdapter = FALSE
case.
So, the remaining strategy is to simply use SuggestedInstanceId instead.
This has the behavior that if there's an adapter already in use, it'll
use a new random GUID. The result is that adapter creation won't fail.
That's not great, but the docs have always made it clear that
"requested" is a best-effort sort of thing. Plus, hopefully the creation
of the new adapter will help nudge the bug a bit and cleanup the old
cruft. In some ways, transitioning from our old strategy of "cudgel the
registry until we get the GUID we want" to "ask politely and accept no
for an answer" is a disappointing regression in functionality. But it
also means we don't need to keep crazy token stealing code around, or
fish around in the registry dangerously. This probably also increases
the likelihood that an adapter will be created during edge cases, which
means fewer errors for users, which could be a good thing. On the
downside, we have the perpetual tensions caused by a system that now
"fails open" instead of "fails closed". But so it goes in Windows land.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
When we install the Wintun driver to the store, we get exact oem<nn>.inf
filename of the driver in the store we just installed. Since the
installation should be only temporarily, we should uninstall only the
driver we installed.
This also eliminates the need for iterating driver store speeding up
things.
The code we removed was inherited from the installer.dll, where it made
perfect sense to remove all installed Wintun drivers in the update
process.
Suggested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Simon Rozman <simon@rozman.si>
Rather than every client reinvent the art of using the Wintun and its
ring buffers, we offer helper structs and functions to unify and
simplify Wintun usage.
Signed-off-by: Simon Rozman <simon@rozman.si>
The SDK header for deployment containing datatype and function
declarations for use by C/C++ clients.
As we shall not distribute MSVC wintun.lib files, making clients need to
use GetProcAddress(), this file contains function type declarations
rather then __declspec(dllimport) function declarations.
Signed-off-by: Simon Rozman <simon@rozman.si>
Gather adapter management in adapter.h/.c (formerly devmgmt.h/.c) and
unify HwID tests.
Use "Namespace" namespace in all functions from namespace.h/.c.
Fix char strings in LOG_...
Signed-off-by: Simon Rozman <simon@rozman.si>
Some functions of SetupAPI only work when invoked from a native process.
Registry and filesystem reflection makes them fail on WoW64. For WoW64
processes, a minimum set of rundll32 functions are provided.
Signed-off-by: Simon Rozman <simon@rozman.si>
Mind that this also fixes the order of adapter detection checks. A fast
test to eliminate non-Wintun adapters from iteration to speed things up
rendered the method incapable of detecting a non-Wintun adapter with the
name we are looking for.
ERROR_OBJECT_NOT_FOUND was replaced with ERROR_FILE_NOT_FOUND.
Signed-off-by: Simon Rozman <simon@rozman.si>
