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reactos/ntoskrnl/ex/uuid.c

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/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
* FILE: ntoskrnl/ex/uuid.c
* PURPOSE: UUID generator
* PROGRAMMERS: Eric Kohl
* Thomas Weidenmueller
* Pierre Schweitzer
*/
/* INCLUDES *****************************************************************/
#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>
#define SEED_BUFFER_SIZE 6
/* Number of 100ns ticks per clock tick. To be safe, assume that the clock
resolution is at least 1000 * 100 * (1/1000000) = 1/10 of a second */
#define TICKS_PER_CLOCK_TICK 1000
#define SECSPERDAY 86400
#define TICKSPERSEC 10000000
/* UUID system time starts at October 15, 1582 */
#define SECS_15_OCT_1582_TO_1601 ((17 + 30 + 31 + 365 * 18 + 5) * SECSPERDAY)
#define TICKS_15_OCT_1582_TO_1601 ((ULONGLONG)SECS_15_OCT_1582_TO_1601 * TICKSPERSEC)
/* 10000 in 100-ns model = 0.1 microsecond */
#define TIME_FRAME 10000
#if defined (ALLOC_PRAGMA)
#pragma alloc_text(INIT, ExpUuidInitialization)
#pragma alloc_text(INIT, ExLuidInitialization)
#endif
/* GLOBALS ****************************************************************/
FAST_MUTEX ExpUuidLock;
LARGE_INTEGER ExpUuidLastTimeAllocated;
ULONG ExpUuidSequenceNumber = 0;
BOOLEAN ExpUuidSequenceNumberValid;
BOOLEAN ExpUuidSequenceNumberNotSaved = FALSE;
UUID_CACHED_VALUES_STRUCT ExpUuidCachedValues = {0ULL, 0xFFFFFFFF, 0, 0, { 0x80, 0x6E, 0x6F, 0x6E, 0x69, 0x63}};
BOOLEAN ExpUuidCacheValid = FALSE;
ULONG ExpLuidIncrement = 1;
LARGE_INTEGER ExpLuid = {{0x3e9, 0x0}};
/* FUNCTIONS ****************************************************************/
/*
* @implemented
*/
BOOLEAN
INIT_FUNCTION
NTAPI
ExpUuidInitialization(VOID)
{
ExInitializeFastMutex(&ExpUuidLock);
ExpUuidSequenceNumberValid = FALSE;
KeQuerySystemTime(&ExpUuidLastTimeAllocated);
return TRUE;
}
/*
* @implemented
*/
#define VALUE_BUFFER_SIZE 20
static NTSTATUS
ExpUuidLoadSequenceNumber(PULONG Sequence)
{
UCHAR ValueBuffer[VALUE_BUFFER_SIZE];
PKEY_VALUE_PARTIAL_INFORMATION ValueInfo;
OBJECT_ATTRIBUTES ObjectAttributes;
UNICODE_STRING KeyName, ValueName;
HANDLE KeyHandle;
ULONG ValueLength;
NTSTATUS Status;
PAGED_CODE();
RtlInitUnicodeString(&KeyName, L"\\Registry\\Machine\\Software\\Microsoft\\Rpc");
RtlInitUnicodeString(&ValueName, L"UuidSequenceNumber");
InitializeObjectAttributes(&ObjectAttributes,
&KeyName,
OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
NULL,
NULL);
Status = ZwOpenKey(&KeyHandle, GENERIC_READ, &ObjectAttributes);
if (!NT_SUCCESS(Status))
{
DPRINT("ZwOpenKey() failed (Status %lx)\n", Status);
return Status;
}
ValueInfo = (PKEY_VALUE_PARTIAL_INFORMATION)ValueBuffer;
Status = ZwQueryValueKey(KeyHandle,
&ValueName,
KeyValuePartialInformation,
ValueBuffer,
VALUE_BUFFER_SIZE,
&ValueLength);
ZwClose(KeyHandle);
if (!NT_SUCCESS(Status))
{
DPRINT("ZwQueryValueKey() failed (Status %lx)\n", Status);
return Status;
}
if (ValueInfo->Type != REG_DWORD || ValueInfo->DataLength != sizeof(DWORD))
{
return STATUS_UNSUCCESSFUL;
}
*Sequence = *((PULONG)ValueInfo->Data);
DPRINT("Loaded sequence %lx\n", *Sequence);
return STATUS_SUCCESS;
}
#undef VALUE_BUFFER_SIZE
/*
* @implemented
*/
static NTSTATUS
ExpUuidSaveSequenceNumber(PULONG Sequence)
{
OBJECT_ATTRIBUTES ObjectAttributes;
UNICODE_STRING KeyName, ValueName;
HANDLE KeyHandle;
NTSTATUS Status;
PAGED_CODE();
RtlInitUnicodeString(&KeyName, L"\\Registry\\Machine\\Software\\Microsoft\\Rpc");
RtlInitUnicodeString(&ValueName, L"UuidSequenceNumber");
InitializeObjectAttributes(&ObjectAttributes,
&KeyName,
OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
NULL,
NULL);
Status = ZwOpenKey(&KeyHandle,
GENERIC_READ | GENERIC_WRITE,
&ObjectAttributes);
if (!NT_SUCCESS(Status))
{
DPRINT("ZwOpenKey() failed (Status %lx)\n", Status);
return Status;
}
Status = ZwSetValueKey(KeyHandle,
&ValueName,
0,
REG_DWORD,
Sequence,
sizeof(ULONG));
ZwClose(KeyHandle);
if (!NT_SUCCESS(Status))
{
DPRINT("ZwSetValueKey() failed (Status %lx)\n", Status);
}
return Status;
}
/*
* @implemented
* Warning! This function must be called
* with ExpUuidLock held!
*/
static VOID
ExpUuidSaveSequenceNumberIf(VOID)
{
NTSTATUS Status;
PAGED_CODE();
/* Only save sequence if it has to */
if (ExpUuidSequenceNumberNotSaved == TRUE)
{
Status = ExpUuidSaveSequenceNumber(&ExpUuidSequenceNumber);
if (NT_SUCCESS(Status))
{
ExpUuidSequenceNumberNotSaved = FALSE;
}
}
}
/*
* @implemented
* Warning! This function must be called
* with ExpUuidLock held!
*/
static NTSTATUS
ExpAllocateUuids(PULARGE_INTEGER Time,
PULONG Range,
PULONG Sequence)
{
NTSTATUS Status;
LARGE_INTEGER Counter, Frequency, CurrentTime, TimeDiff, ClockDiff;
PAGED_CODE();
/* Initialize sequence number */
if (!ExpUuidSequenceNumberValid)
{
/* Try to load sequence number */
Status = ExpUuidLoadSequenceNumber(&ExpUuidSequenceNumber);
if (NT_SUCCESS(Status))
{
++ExpUuidSequenceNumber;
}
else
{
/* If we cannot, generate a "true" random */
Counter = KeQueryPerformanceCounter(&Frequency);
ExpUuidSequenceNumber ^= (ULONG_PTR)&Status ^ (ULONG_PTR)Sequence ^ Counter.LowPart ^ Counter.HighPart;
}
/* It's valid and to be saved */
ExpUuidSequenceNumberValid = TRUE;
ExpUuidSequenceNumberNotSaved = TRUE;
}
KeQuerySystemTime(&CurrentTime);
TimeDiff.QuadPart = CurrentTime.QuadPart - ExpUuidLastTimeAllocated.QuadPart;
/* If time went backwards, change sequence (see RFC example) */
if (TimeDiff.QuadPart < 0)
{
++ExpUuidSequenceNumber;
TimeDiff.QuadPart = 2 * TIME_FRAME;
/* It's to be saved */
ExpUuidSequenceNumberNotSaved = TRUE;
ExpUuidLastTimeAllocated.QuadPart = CurrentTime.QuadPart - 2 * TIME_FRAME;
}
if (TimeDiff.QuadPart == 0)
{
return STATUS_RETRY;
}
/* If time diff > 0.1ms, squash it to reduce it to keep our clock resolution */
if (TimeDiff.HighPart > 0 || TimeDiff.QuadPart > TICKS_PER_CLOCK_TICK * TIME_FRAME)
{
TimeDiff.QuadPart = TICKS_PER_CLOCK_TICK * TIME_FRAME;
}
if (TimeDiff.HighPart < 0 || TimeDiff.QuadPart <= TIME_FRAME)
{
*Range = TimeDiff.QuadPart;
ClockDiff.QuadPart = 0LL;
}
else
{
*Range = TIME_FRAME;
ClockDiff.QuadPart = TimeDiff.QuadPart - TIME_FRAME;
--ClockDiff.HighPart;
}
Time->QuadPart = CurrentTime.QuadPart - *Range - ClockDiff.QuadPart;
ExpUuidLastTimeAllocated.QuadPart = CurrentTime.QuadPart - ClockDiff.QuadPart;
*Sequence = ExpUuidSequenceNumber;
return STATUS_SUCCESS;
}
/*
* @implemented
* Warning! This function must be called
* with ExpUuidLock held!
*/
static NTSTATUS
ExpUuidGetValues(PUUID_CACHED_VALUES_STRUCT CachedValues)
{
NTSTATUS Status;
ULARGE_INTEGER Time;
ULONG Range;
ULONG Sequence;
PAGED_CODE();
/* Allocate UUIDs */
Status = ExpAllocateUuids(&Time, &Range, &Sequence);
if (Status == STATUS_RETRY)
{
return Status;
}
if (!NT_SUCCESS(Status))
{
return STATUS_NO_MEMORY;
}
/* We need at least one UUID */
ASSERT(Range != 0);
/* Set up our internal cache
* See format_uuid_v1 in RFC4122 for magic values
*/
CachedValues->ClockSeqLow = Sequence;
CachedValues->ClockSeqHiAndReserved = (Sequence & 0x3F00) >> 8;
CachedValues->ClockSeqHiAndReserved |= 0x80;
CachedValues->AllocatedCount = Range;
/*
* Time is relative to UUID time
* And we set last time range for all the possibly
* returnable UUID
*/
Time.QuadPart += TICKS_15_OCT_1582_TO_1601;
CachedValues->Time = Time.QuadPart + (Range - 1);
return STATUS_SUCCESS;
}
/*
* @implemented
*/
BOOLEAN
INIT_FUNCTION
NTAPI
ExLuidInitialization(VOID)
{
return TRUE;
}
/*
* @implemented
*/
VOID
NTAPI
ExAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
{
/* Atomically increment the luid */
*(LONG64*)LocallyUniqueId = InterlockedExchangeAdd64(&ExpLuid.QuadPart,
ExpLuidIncrement);
}
/*
* @implemented
*/
NTSTATUS
NTAPI
NtAllocateLocallyUniqueId(OUT LUID *LocallyUniqueId)
{
KPROCESSOR_MODE PreviousMode;
PAGED_CODE();
/* Probe if user mode */
PreviousMode = ExGetPreviousMode();
if (PreviousMode != KernelMode)
{
_SEH2_TRY
{
ProbeForWrite(LocallyUniqueId,
sizeof(LUID),
sizeof(ULONG));
}
_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
{
_SEH2_YIELD(return _SEH2_GetExceptionCode());
}
_SEH2_END;
}
/* Do the allocation */
ExAllocateLocallyUniqueId(LocallyUniqueId);
return STATUS_SUCCESS;
}
/*
* @implemented
*/
NTSTATUS
NTAPI
ExUuidCreate(OUT UUID *Uuid)
{
NTSTATUS Status;
LONG AllocatedCount;
LARGE_INTEGER Time;
BOOLEAN Valid;
PAGED_CODE();
Status = STATUS_SUCCESS;
/* Loop until we have an UUID to return */
while (TRUE)
{
/* Try to gather node values */
do
{
Time.QuadPart = ExpUuidCachedValues.Time;
RtlCopyMemory(&Uuid->Data4[0],
&ExpUuidCachedValues.NodeId[0],
SEED_BUFFER_SIZE);
Valid = ExpUuidCacheValid;
AllocatedCount = InterlockedDecrement(&ExpUuidCachedValues.AllocatedCount);
}
/* Loop till we can do it without being disturbed */
while (Time.QuadPart != ExpUuidCachedValues.Time);
/* We have more than an allocated UUID left, that's OK to return! */
if (AllocatedCount >= 0)
{
break;
}
/*
* Here, we're out of UUIDs, we need to allocate more
* We need to be alone to do it, so lock the mutex
*/
ExAcquireFastMutex(&ExpUuidLock);
if (Time.QuadPart == ExpUuidCachedValues.Time)
{
/* If allocation fails, bail out! */
Status = ExpUuidGetValues(&ExpUuidCachedValues);
if (Status != STATUS_SUCCESS)
{
ExReleaseFastMutex(&ExpUuidLock);
return Status;
}
/* Save our current sequence if changed */
ExpUuidSaveSequenceNumberIf();
}
ExReleaseFastMutex(&ExpUuidLock);
}
/*
* Once here, we've got an UUID to return
* But, if our init wasn't sane, then, make
* sure it's only used locally
*/
if (!Valid)
{
Status = RPC_NT_UUID_LOCAL_ONLY;
}
/* Set our timestamp - see RFC4211 */
Time.QuadPart -= AllocatedCount;
Uuid->Data1 = Time.LowPart;
Uuid->Data2 = Time.HighPart;
/* We also set the bit for GUIDv1 */
Uuid->Data3 = ((Time.HighPart >> 16) & 0x0FFF) | 0x1000;
return Status;
}
/*
* @implemented
*/
NTSTATUS
NTAPI
NtAllocateUuids(OUT PULARGE_INTEGER Time,
OUT PULONG Range,
OUT PULONG Sequence,
OUT PUCHAR Seed)
{
ULARGE_INTEGER IntTime;
ULONG IntRange, IntSequence;
NTSTATUS Status;
KPROCESSOR_MODE PreviousMode;
PAGED_CODE();
/* Probe if user mode */
PreviousMode = ExGetPreviousMode();
if (PreviousMode != KernelMode)
{
_SEH2_TRY
{
ProbeForWrite(Time,
sizeof(ULARGE_INTEGER),
sizeof(ULONG));
ProbeForWrite(Range,
sizeof(ULONG),
sizeof(ULONG));
ProbeForWrite(Sequence,
sizeof(ULONG),
sizeof(ULONG));
ProbeForWrite(Seed,
SEED_BUFFER_SIZE,
sizeof(UCHAR));
}
_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
{
_SEH2_YIELD(return _SEH2_GetExceptionCode());
}
_SEH2_END;
}
/* During allocation we must be alone */
ExAcquireFastMutex(&ExpUuidLock);
Status = ExpAllocateUuids(&IntTime,
&IntRange,
&IntSequence);
if (!NT_SUCCESS(Status))
{
ExReleaseFastMutex(&ExpUuidLock);
return Status;
}
/* If sequence number was changed, save it */
ExpUuidSaveSequenceNumberIf();
/* Allocation done, so we can release */
ExReleaseFastMutex(&ExpUuidLock);
/* Write back UUIDs to caller */
_SEH2_TRY
{
Time->QuadPart = IntTime.QuadPart;
*Range = IntRange;
*Sequence = IntSequence;
RtlCopyMemory(Seed,
&ExpUuidCachedValues.NodeId[0],
SEED_BUFFER_SIZE);
Status = STATUS_SUCCESS;
}
_SEH2_EXCEPT(ExSystemExceptionFilter())
{
Status = _SEH2_GetExceptionCode();
}
_SEH2_END;
return Status;
}
/*
* @implemented
*/
NTSTATUS
NTAPI
NtSetUuidSeed(IN PUCHAR Seed)
{
NTSTATUS Status;
BOOLEAN GotContext;
PACCESS_TOKEN Token;
SECURITY_SUBJECT_CONTEXT SubjectContext;
LUID CallerLuid, SystemLuid = SYSTEM_LUID;
PAGED_CODE();
/* Should only be done by umode */
ASSERT(KeGetPreviousMode() != KernelMode);
/* No context to release */
GotContext = FALSE;
_SEH2_TRY
{
/* Get our caller context and remember to release it */
SeCaptureSubjectContext(&SubjectContext);
GotContext = TRUE;
/* Get caller access token and its associated ID */
Token = SeQuerySubjectContextToken(&SubjectContext);
Status = SeQueryAuthenticationIdToken(Token, &CallerLuid);
if (!NT_SUCCESS(Status))
{
RtlRaiseStatus(Status);
}
/* This call is only allowed for SYSTEM */
if (!RtlEqualLuid(&CallerLuid, &SystemLuid))
{
RtlRaiseStatus(STATUS_ACCESS_DENIED);
}
/* Check for buffer validity and then copy it to our seed */
ProbeForRead(Seed, SEED_BUFFER_SIZE, sizeof(UCHAR));
RtlCopyMemory(&ExpUuidCachedValues.NodeId[0], Seed, SEED_BUFFER_SIZE);
/*
* According to RFC 4122, UUID seed is based on MAC addresses
* If it is randomly set, then, it must have its multicast be set
* to be valid and avoid collisions
* Reflect it here
*/
ExpUuidCacheValid = ~(*Seed >> 7) & 1;
Status = STATUS_SUCCESS;
}
_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
{
Status = _SEH2_GetExceptionCode();
}
_SEH2_END;
/* Release context if required */
if (GotContext)
{
SeReleaseSubjectContext(&SubjectContext);
}
return Status;
}
/* EOF */
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