Hesham/wintun
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Allow buffer mapping to happen concurrently

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-06-27 09:08:57 +00:00
parent 88bde5b28e
commit d82a68f830
1 changed files with 39 additions and 17 deletions
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56
wintun.c
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@ -112,9 +112,11 @@ typedef struct _TUN_CTX
typedef struct _TUN_MAPPED_UBUFFER typedef struct _TUN_MAPPED_UBUFFER
{ {
VOID *UserAddress, *KernelAddress; VOID *volatile UserAddress;
VOID *KernelAddress;
MDL *Mdl; MDL *Mdl;
ULONG Size; ULONG Size;
FAST_MUTEX InitializationComplete;
// TODO: ThreadID for checking // TODO: ThreadID for checking
} TUN_MAPPED_UBUFFER; } TUN_MAPPED_UBUFFER;
@ -295,38 +297,56 @@ _Must_inspect_result_
static NTSTATUS static NTSTATUS
TunMapUbuffer(_Inout_ TUN_MAPPED_UBUFFER *MappedBuffer, _In_ VOID *UserAddress, _In_ ULONG Size) TunMapUbuffer(_Inout_ TUN_MAPPED_UBUFFER *MappedBuffer, _In_ VOID *UserAddress, _In_ ULONG Size)
{ {
if (MappedBuffer->UserAddress) VOID *current_uaddr = InterlockedGetPointer(&MappedBuffer->UserAddress);
if (current_uaddr)
{ {
if (UserAddress == MappedBuffer->UserAddress) // TODO: Check ThreadID if (UserAddress == current_uaddr) // TODO: Check ThreadID
return STATUS_SUCCESS; return STATUS_SUCCESS;
return STATUS_ALREADY_INITIALIZED; return STATUS_ALREADY_INITIALIZED;
} }
NTSTATUS status = STATUS_SUCCESS;
ExAcquireFastMutex(&MappedBuffer->InitializationComplete);
// Recheck the same thing as above, but locked this time.
current_uaddr = InterlockedGetPointer(&MappedBuffer->UserAddress);
if (current_uaddr)
{
if (UserAddress != current_uaddr) // TODO: Check ThreadID
status = STATUS_ALREADY_INITIALIZED;
goto err_releasemutex;
}
MappedBuffer->Mdl = IoAllocateMdl(UserAddress, Size, FALSE, FALSE, NULL); MappedBuffer->Mdl = IoAllocateMdl(UserAddress, Size, FALSE, FALSE, NULL);
status = STATUS_INSUFFICIENT_RESOURCES;
if (!MappedBuffer->Mdl) if (!MappedBuffer->Mdl)
return STATUS_INSUFFICIENT_RESOURCES; goto err_releasemutex;
status = STATUS_INVALID_USER_BUFFER;
try try
{ {
MmProbeAndLockPages(MappedBuffer->Mdl, UserMode, IoWriteAccess); MmProbeAndLockPages(MappedBuffer->Mdl, UserMode, IoWriteAccess);
} }
except(EXCEPTION_EXECUTE_HANDLER) except(EXCEPTION_EXECUTE_HANDLER) { goto err_freemdl; }
{
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
return STATUS_INVALID_USER_BUFFER;
}
MappedBuffer->KernelAddress = MappedBuffer->KernelAddress =
MmGetSystemAddressForMdlSafe(MappedBuffer->Mdl, NormalPagePriority | MdlMappingNoExecute); MmGetSystemAddressForMdlSafe(MappedBuffer->Mdl, NormalPagePriority | MdlMappingNoExecute);
status = STATUS_INSUFFICIENT_RESOURCES;
if (!MappedBuffer->KernelAddress) if (!MappedBuffer->KernelAddress)
{ goto err_unlockmdl;
MmUnlockPages(MappedBuffer->Mdl);
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
return STATUS_INSUFFICIENT_RESOURCES;
}
MappedBuffer->UserAddress = UserAddress;
MappedBuffer->Size = Size; MappedBuffer->Size = Size;
InterlockedExchangePointer(&MappedBuffer->UserAddress, UserAddress);
ExReleaseFastMutex(&MappedBuffer->InitializationComplete);
return STATUS_SUCCESS; return STATUS_SUCCESS;
err_unlockmdl:
MmUnlockPages(MappedBuffer->Mdl);
err_freemdl:
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
err_releasemutex:
ExReleaseFastMutex(&MappedBuffer->InitializationComplete);
return status;
} }
_IRQL_requires_max_(DISPATCH_LEVEL) _IRQL_requires_max_(DISPATCH_LEVEL)
@ -974,6 +994,8 @@ TunDispatchCreate(_Inout_ TUN_CTX *Ctx, _Inout_ IRP *Irp)
if (!file_ctx) if (!file_ctx)
return STATUS_INSUFFICIENT_RESOURCES; return STATUS_INSUFFICIENT_RESOURCES;
RtlZeroMemory(file_ctx, sizeof(*file_ctx)); RtlZeroMemory(file_ctx, sizeof(*file_ctx));
ExInitializeFastMutex(&file_ctx->ReadBuffer.InitializationComplete);
ExInitializeFastMutex(&file_ctx->WriteBuffer.InitializationComplete);
KIRQL irql = ExAcquireSpinLockShared(&Ctx->TransitionLock); KIRQL irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
LONG flags = InterlockedGet(&Ctx->Flags); LONG flags = InterlockedGet(&Ctx->Flags);