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Delay exit from HaltEx

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-05-31 12:40:49 +00:00
parent c19da2a99e
commit 888cad7f2a
1 changed files with 30 additions and 1 deletions
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31
wintun.c
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@ -90,11 +90,14 @@ typedef struct _TUN_CTX {
} PacketQueue;
NDIS_HANDLE NBLPool;
ULONG NetLuidIndex;
} TUN_CTX;
static UINT NdisVersion;
static PVOID TunNotifyInterfaceChangeHandle;
static NDIS_HANDLE NdisMiniportDriverHandle;
static volatile LONG64 AdapterCount;
#if REG_DWORD == REG_DWORD_BIG_ENDIAN
#define TUN_MEMORY_TAG 'wtun'
@ -1088,6 +1091,7 @@ static NDIS_STATUS TunInitializeEx(NDIS_HANDLE MiniportAdapterHandle, NDIS_HANDL
InterlockedExchange((LONG *)&ctx->State, TUN_STATE_INITIALIZING);
InterlockedExchange((LONG *)&ctx->PowerState, NdisDeviceStateD0);
ctx->MiniportAdapterHandle = MiniportAdapterHandle;
ctx->NetLuidIndex = (ULONG)MiniportInitParameters->NetLuid.Info.NetLuidIndex;
ctx->Statistics.Header.Type = NDIS_OBJECT_TYPE_DEFAULT;
ctx->Statistics.Header.Revision = NDIS_STATISTICS_INFO_REVISION_1;
@ -1239,7 +1243,7 @@ static NDIS_STATUS TunInitializeEx(NDIS_HANDLE MiniportAdapterHandle, NDIS_HANDL
* of the MiniportInitializeEx function.
*/
TunIndicateStatus(MiniportAdapterHandle, MediaConnectStateDisconnected);
InterlockedIncrement64(&AdapterCount);
InterlockedExchange((LONG *)&ctx->State, TUN_STATE_PAUSED);
return NDIS_STATUS_SUCCESS;
@ -1258,6 +1262,28 @@ static VOID TunUnload(PDRIVER_OBJECT DriverObject)
NdisMDeregisterMiniportDriver(NdisMiniportDriverHandle);
}
_IRQL_requires_max_(APC_LEVEL)
static void TunWaitForReferencesToDropToZero(_Inout_ TUN_CTX *ctx)
{
/* It's a bit annoying to reconstruct this here, but it's better than storing it, and
* although we could just get it from ndishandle+288, that's probably a bit dirty. */
WCHAR symbolic_name[sizeof(L"\\DosDevices\\" TUN_DEVICE_NAME) / sizeof(WCHAR) + 10/*MAXULONG as string*/] = { 0 };
UNICODE_STRING unicode_symbolic_name;
TunInitUnicodeString(&unicode_symbolic_name, symbolic_name);
RtlUnicodeStringPrintf(&unicode_symbolic_name, L"\\DosDevices\\" TUN_DEVICE_NAME, ctx->NetLuidIndex);
/* We first get rid of the symbolic link, to prevent userspace from accidently reopening
* this while we're waiting for the refcount to drop to zero. It might still be possible to
* open it from the real path, in which case, maybe we should consider setting a deny-all DACL. */
IoDeleteSymbolicLink(&unicode_symbolic_name);
/* The sleep loop isn't pretty, but we don't have a choice. This is an NDIS bug we're working around. */
enum { SleepTime = 50, TotalTime = 2 * 60 * 1000, MaxTries = TotalTime / SleepTime };
#pragma warning(suppress: 28175)
for (int i = 0; i < MaxTries && ctx->Device.Object->ReferenceCount; ++i)
NdisMSleep(SleepTime);
}
static MINIPORT_HALT TunHaltEx;
_Use_decl_annotations_
static void TunHaltEx(NDIS_HANDLE MiniportAdapterContext, NDIS_HALT_ACTION HaltAction)
@ -1295,6 +1321,9 @@ static void TunHaltEx(NDIS_HANDLE MiniportAdapterContext, NDIS_HALT_ACTION HaltA
InterlockedExchange((LONG *)&ctx->PowerState, NdisDeviceStateUnspecified);
InterlockedExchange((LONG *)&ctx->State, TUN_STATE_HALTED);
if (!InterlockedDecrement64(&AdapterCount))
TunWaitForReferencesToDropToZero(ctx);
/* Deregister device _after_ we are done writing to ctx not to risk an UaF. The ctx is hosted by device extension. */
NdisDeregisterDeviceEx(ctx->Device.Handle);
}