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sys: FspFsvolDeviceInsertContext: can no longer fail because of low memory

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This commit is contained in:
Bill Zissimopoulos 2015-12-05 23:00:33 -08:00
parent bdc7033740
commit df340872f7
3 changed files with 74 additions and 49 deletions
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82
src/sys/create.c
View File

@ -346,6 +346,20 @@ VOID FspFsvolCreateComplete(
{
FSP_ENTER_IOC(PAGED_CODE());
/*
* NOTE:
* In the following we may have to close the just opened file object. But we must
* never close a file we just created, because this will leave an orphan file on
* the disk.
*
* Files may have to be closed if a security access or share access check fails. In
* both those cases we were opening an existing file and so it is safe to close it.
*
* Because of how IRP_MJ_CREATE works in Windows, it is difficult to improve on this
* scheme without introducing a 2-phase Create protocol, which is undesirable as it
* means two trips into user-mode for a single Create request.
*/
PDEVICE_OBJECT DeviceObject = IrpSp->DeviceObject;
FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(DeviceObject);
FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension =
@ -400,11 +414,11 @@ VOID FspFsvolCreateComplete(
goto reparse_fail;
}
ExFreePool(FileObject->FileName.Buffer);
FileObject->FileName.Length = 0;
FileObject->FileName.MaximumLength = ReparseFileName.Length;
FileObject->FileName.Buffer = Buffer;
RtlCopyUnicodeString(&FileObject->FileName, &ReparseFileName);
}
FileObject->FileName.Length = 0;
RtlCopyUnicodeString(&FileObject->FileName, &ReparseFileName);
}
else
if (IO_REMOUNT == Response->IoStatus.Information)
@ -471,43 +485,43 @@ VOID FspFsvolCreateComplete(
ExAcquireResourceExclusiveLite(&FsvolDeviceExtension->Base.Resource, TRUE);
try
{
/* attempt to insert the newly created FsContext into our generic table */
/* insert the newly created FsContext into our generic table */
FsContext = FspFsvolDeviceInsertContext(DeviceObject,
FsContext->UserContext, FsContext, &Inserted);
if (0 == FsContext)
Result = STATUS_INSUFFICIENT_RESOURCES;
FsContext->UserContext, FsContext, &FsContext->ElementStorage, &Inserted);
ASSERT(0 != FsContext);
/* share access check */
if (Inserted)
{
/*
* This is a newly created FsContext. Set its share access and
* increment its open count. There is no need to acquire the
* FsContext's Resource (because it is newly created).
*/
IoSetShareAccess(AccessState->PreviouslyGrantedAccess,
ShareAccess, FileObject, &FsContext->ShareAccess);
FspFileContextOpen(FsContext);
Result = STATUS_SUCCESS;
}
else
{
/* share access check */
if (Inserted)
{
/*
* This is a newly created FsContext. Set its share access and
* increment its open count. There is no need to acquire the
* FsContext's Resource (because it is newly created).
*/
IoSetShareAccess(AccessState->PreviouslyGrantedAccess,
ShareAccess, FileObject, &FsContext->ShareAccess);
FspFileContextOpen(FsContext);
Result = STATUS_SUCCESS;
}
/*
* This is an existing FsContext. We must acquire its Resource and
* check if there is a delete pending and the share access. Only if
* both tests succeed we increment the open count and report success.
*/
ExAcquireResourceExclusiveLite(FsContext->Header.Resource, TRUE);
if (FsContext->DeletePending)
Result = STATUS_DELETE_PENDING;
else
Result = IoCheckShareAccess(AccessState->PreviouslyGrantedAccess,
ShareAccess, FileObject, &FsContext->ShareAccess, TRUE);
if (NT_SUCCESS(Result))
{
/*
* This is an existing FsContext. We must acquire its Resource and
* check if there is a delete pending and the share access. Only if
* both tests succeed we increment the open count and report success.
*/
ExAcquireResourceExclusiveLite(FsContext->Header.Resource, TRUE);
if (FsContext->DeletePending)
Result = STATUS_DELETE_PENDING;
else
Result = IoCheckShareAccess(AccessState->PreviouslyGrantedAccess,
ShareAccess, FileObject, &FsContext->ShareAccess, TRUE);
if (NT_SUCCESS(Result))
FspFileContextOpen(FsContext);
ExReleaseResourceLite(FsContext->Header.Resource);
FspFileContextRetain(FsContext);
FspFileContextOpen(FsContext);
}
ExReleaseResourceLite(FsContext->Header.Resource);
}
}
finally
@ -515,7 +529,7 @@ VOID FspFsvolCreateComplete(
ExReleaseResourceLite(&FsvolDeviceExtension->Base.Resource);
}
/* did we fail to insert? */
/* did we fail our share access checks? */
if (!NT_SUCCESS(Result))
{
ASSERT(!Inserted);

27
src/sys/device.c
View File

@ -26,7 +26,7 @@ VOID FspFsctlDeviceVolumeCreated(PDEVICE_OBJECT DeviceObject);
VOID FspFsctlDeviceVolumeDeleted(PDEVICE_OBJECT DeviceObject);
PVOID FspFsvolDeviceLookupContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier);
PVOID FspFsvolDeviceInsertContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier, PVOID Context,
PBOOLEAN PInserted);
FSP_DEVICE_GENERIC_TABLE_ELEMENT *ElementStorage, PBOOLEAN PInserted);
VOID FspFsvolDeviceDeleteContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier,
PBOOLEAN PDeleted);
static RTL_AVL_COMPARE_ROUTINE FspFsvolDeviceCompareElement;
@ -61,12 +61,6 @@ VOID FspDeviceDeleteAll(VOID);
#pragma alloc_text(PAGE, FspDeviceDeleteAll)
#endif
typedef struct
{
UINT64 Identifier;
PVOID Context;
} FSP_DEVICE_GENERIC_TABLE_ELEMENT;
NTSTATUS FspDeviceCreateSecure(UINT32 Kind, ULONG ExtraSize,
PUNICODE_STRING DeviceName, DEVICE_TYPE DeviceType,
PUNICODE_STRING DeviceSddl, LPCGUID DeviceClassGuid,
@ -236,7 +230,7 @@ static VOID FspFsvolDeviceFini(PDEVICE_OBJECT DeviceObject)
* Enumerate and delete all entries in the GenericTable.
* There is no need to protect accesses to the table as we are in the device destructor.
*/
FSP_DEVICE_GENERIC_TABLE_ELEMENT *Element;
FSP_DEVICE_GENERIC_TABLE_ELEMENT_DATA *Element;
while (0 != (Element = RtlGetElementGenericTableAvl(&FsvolDeviceExtension->GenericTable, 0)))
RtlDeleteElementGenericTableAvl(&FsvolDeviceExtension->GenericTable, &Element->Identifier);
@ -318,7 +312,7 @@ PVOID FspFsvolDeviceLookupContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier
ASSERT(FspFsvolDeviceExtensionKind == FsvolDeviceExtension->Base.Kind);
ASSERT(ExIsResourceAcquiredExclusiveLite(&FsvolDeviceExtension->Base.Resource));
FSP_DEVICE_GENERIC_TABLE_ELEMENT *Result;
FSP_DEVICE_GENERIC_TABLE_ELEMENT_DATA *Result;
Result = RtlLookupElementGenericTableAvl(&FsvolDeviceExtension->GenericTable, &Identifier);
@ -326,7 +320,7 @@ PVOID FspFsvolDeviceLookupContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier
}
PVOID FspFsvolDeviceInsertContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier, PVOID Context,
PBOOLEAN PInserted)
FSP_DEVICE_GENERIC_TABLE_ELEMENT *ElementStorage, PBOOLEAN PInserted)
{
PAGED_CODE();
@ -334,12 +328,14 @@ PVOID FspFsvolDeviceInsertContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier
ASSERT(FspFsvolDeviceExtensionKind == FsvolDeviceExtension->Base.Kind);
ASSERT(ExIsResourceAcquiredExclusiveLite(&FsvolDeviceExtension->Base.Resource));
FSP_DEVICE_GENERIC_TABLE_ELEMENT *Result, Element = { 0 };
FSP_DEVICE_GENERIC_TABLE_ELEMENT_DATA *Result, Element = { 0 };
Element.Identifier = Identifier;
Element.Context = Context;
FsvolDeviceExtension->GenericTableElementStorage = ElementStorage;
Result = RtlInsertElementGenericTableAvl(&FsvolDeviceExtension->GenericTable,
&Element, sizeof Element, PInserted);
FsvolDeviceExtension->GenericTableElementStorage = 0;
return 0 != Result ? Result->Context : 0;
}
@ -380,15 +376,18 @@ static PVOID NTAPI FspFsvolDeviceAllocateElement(
{
PAGED_CODE();
return ExAllocatePoolWithTag(PagedPool, ByteSize, FSP_TAG);
FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension =
CONTAINING_RECORD(Table, FSP_FSVOL_DEVICE_EXTENSION, GenericTable);
ASSERT(sizeof(FSP_DEVICE_GENERIC_TABLE_ELEMENT) == ByteSize);
return FsvolDeviceExtension->GenericTableElementStorage;
}
static VOID NTAPI FspFsvolDeviceFreeElement(
PRTL_AVL_TABLE Table, PVOID Buffer)
{
PAGED_CODE();
ExFreePoolWithTag(Buffer, FSP_TAG);
}
NTSTATUS FspDeviceCopyList(

14
src/sys/driver.h
View File

@ -305,7 +305,18 @@ typedef struct
FSP_DEVICE_EXTENSION Base;
PDEVICE_OBJECT FsvrtDeviceObject;
RTL_AVL_TABLE GenericTable;
PVOID GenericTableElementStorage;
} FSP_FSVOL_DEVICE_EXTENSION;
typedef struct
{
UINT64 Identifier;
PVOID Context;
} FSP_DEVICE_GENERIC_TABLE_ELEMENT_DATA;
typedef struct
{
RTL_BALANCED_LINKS Header;
FSP_DEVICE_GENERIC_TABLE_ELEMENT_DATA Data;
} FSP_DEVICE_GENERIC_TABLE_ELEMENT;
static inline
FSP_DEVICE_EXTENSION *FspDeviceExtension(PDEVICE_OBJECT DeviceObject)
{
@ -343,7 +354,7 @@ VOID FspFsctlDeviceVolumeCreated(PDEVICE_OBJECT DeviceObject);
VOID FspFsctlDeviceVolumeDeleted(PDEVICE_OBJECT DeviceObject);
PVOID FspFsvolDeviceLookupContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier);
PVOID FspFsvolDeviceInsertContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier, PVOID Context,
PBOOLEAN PInserted);
FSP_DEVICE_GENERIC_TABLE_ELEMENT *ElementStorage, PBOOLEAN PInserted);
VOID FspFsvolDeviceDeleteContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier,
PBOOLEAN PDeleted);
NTSTATUS FspDeviceCopyList(
@ -370,6 +381,7 @@ typedef struct
SHARE_ACCESS ShareAccess;
BOOLEAN DeletePending;
/* read-only after creation */
FSP_DEVICE_GENERIC_TABLE_ELEMENT ElementStorage;
UINT64 UserContext;
UNICODE_STRING FileName;
WCHAR FileNameBuf[];