VOID
NcSetFileName (
_In_ PVOID Entry,
_In_ PWSTR NewName,
_In_ ULONG Length,
_In_ CONST PDIRECTORY_CONTROL_OFFSETS Offsets,
_In_ BOOLEAN ForceLast
)
/*++
Routine Description:
Sets a new file name into the entry.
Arguments:
Entry - A pointer to the start of the entry.
NewName - A pointer to the new file name.
Length - The length of the new name (in bytes).
Offsets - Offsets structure for the information class.
ForceLast - If true, the entry's size will be set to zero
so that it looks like a valid last entry.
Return Value
None.
--*/
{
PWSTR NamePtr;
PULONG NameLength;
PAGED_CODE();
//
// Get a pointer to the name in the buffer.
//
NamePtr = NcGetFileName( Entry, Offsets);
NameLength = Add2Ptr( Entry, Offsets->FileNameLengthDist );
//
// Copy the new name into buffer.
//
RtlCopyMemory( NamePtr, NewName, Length );
*NameLength = Length;
//
// Now we have to update the size of this entry.
//
NcSetNextEntryOffset( Entry, Offsets, ForceLast );
}
FLT_PREOP_CALLBACK_STATUS
NcEnumerateDirectory (
_Inout_ PFLT_CALLBACK_DATA Data,
_In_ PCFLT_RELATED_OBJECTS FltObjects,
_Flt_CompletionContext_Outptr_ PVOID *CompletionContext
)
/*++
Routine Description:
Routine is invoked when a directory enumeration is issued by the
user.
Arguments:
Data - Pointer to the filter CallbackData that is passed to us.
FltObjects - Pointer to the FLT_RELATED_OBJECTS data structure containing
opaque handles to this filter, instance, its associated volume and
file object.
CompletionContext - The context for the completion routine for this
operation.
Return Value:
The return value is the Status of the operation.
--*/
{
//TODO WE SHOULD CONSIDER MOVING THIS TO POST BECAUSE NTFS WILL TAKE CARE
// OF SYNC.
FLT_PREOP_CALLBACK_STATUS ReturnValue;
NTSTATUS Status;
PNC_INSTANCE_CONTEXT InstanceContext = NULL;
PNC_STREAM_HANDLE_CONTEXT HandleContext = NULL;
PNC_DIR_QRY_CONTEXT DirCtx = NULL;
PFLT_FILE_NAME_INFORMATION FileNameInformation = NULL;
NC_PATH_OVERLAP RealOverlap;
NC_PATH_OVERLAP UserOverlap;
BOOLEAN Reset = BooleanFlagOn( Data->Iopb->OperationFlags, SL_RESTART_SCAN );
BOOLEAN FirstQuery;
BOOLEAN Single = BooleanFlagOn( Data->Iopb->OperationFlags, SL_RETURN_SINGLE_ENTRY );
BOOLEAN IgnoreCase = !BooleanFlagOn( FltObjects->FileObject->Flags,
FO_OPENED_CASE_SENSITIVE );
FILE_INFORMATION_CLASS InformationClass =
Data->Iopb->Parameters.DirectoryControl.QueryDirectory.FileInformationClass;
PVOID UserBuffer;
ULONG BufferSize; //size for user and system buffers.
BOOLEAN Unlock = FALSE;
//Vars for moving data into user buffer.
ULONG NumEntriesCopied;
ULONG UserBufferOffset;
ULONG LastEntryStart;
BOOLEAN MoreRoom;
PNC_CACHE_ENTRY NextEntry;
DIRECTORY_CONTROL_OFFSETS Offsets;
BOOLEAN FoundStructureOffsets;
UNREFERENCED_PARAMETER( CompletionContext );
PAGED_CODE();
FLT_ASSERT( IoGetTopLevelIrp() == NULL );
FoundStructureOffsets = NcDetermineStructureOffsets( &Offsets,
InformationClass );
if (!FoundStructureOffsets) {
Status = STATUS_INVALID_PARAMETER;
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
//
// Get our instance context.
//
Status = FltGetInstanceContext( FltObjects->Instance,
&InstanceContext );
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
//
// Get the directory's name.
//
Status = NcGetFileNameInformation( Data,
NULL,
NULL,
FLT_FILE_NAME_OPENED | FLT_FILE_NAME_QUERY_DEFAULT,
&FileNameInformation );
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
Status = FltParseFileNameInformation( FileNameInformation );
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
//
// See if the directory is parent of either mapping.
//
NcComparePath( &FileNameInformation->Name,
&InstanceContext->Mapping.UserMapping,
NULL,
IgnoreCase,
TRUE,
&UserOverlap );
NcComparePath( &FileNameInformation->Name,
&InstanceContext->Mapping.RealMapping,
NULL,
IgnoreCase,
TRUE,
&RealOverlap );
if (!(UserOverlap.Parent || RealOverlap.Parent )) {
//
// We are not interested in this directory
// because it is not the parent of either
// mapping. This means we can just passthrough.
//
Status = STATUS_SUCCESS;
ReturnValue = FLT_PREOP_SUCCESS_NO_CALLBACK;
goto NcEnumerateDirectoryCleanup;
}
Status = NcStreamHandleContextAllocAndAttach( FltObjects->Filter,
FltObjects->Instance,
FltObjects->FileObject,
&HandleContext );
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
FLT_ASSERT( HandleContext != NULL );
DirCtx = &HandleContext->DirectoryQueryContext;
_Analysis_assume_( DirCtx != NULL );
//
// Before looking at the context, we have to acquire the lock.
//
NcLockStreamHandleContext( HandleContext );
Unlock = TRUE;
//
// We don't allow multiple outstanding enumeration requests on
// a single handle.
//
// TODO: This needs to change.
//
if (DirCtx->EnumerationOutstanding) {
Status = STATUS_UNSUCCESSFUL;
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
DirCtx->EnumerationOutstanding = TRUE;
//
// Now drop the lock. We're protected by the EnumerationOutstanding
// flag; nobody else can muck with the enumeration context structure.
//
NcUnlockStreamHandleContext( HandleContext );
Unlock = FALSE;
//
// Now we need to initialize or clear the cache and query options.
//
Status = NcStreamHandleContextEnumSetup( DirCtx,
InstanceContext,
&Offsets,
Data,
FltObjects,
UserOverlap,
&FirstQuery );
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
//
// Prepare to populate the user buffer.
//
UserBuffer = Data->Iopb->Parameters.DirectoryControl.QueryDirectory.DirectoryBuffer;
BufferSize = Data->Iopb->Parameters.DirectoryControl.QueryDirectory.Length;
//
// Lets copy data into the user buffer.
//
NumEntriesCopied = 0;
UserBufferOffset = 0;
do {
//
// If there is no cache entry, populate it.
//
if (DirCtx->Cache.Buffer == NULL) {
Status = NcPopulateCacheEntry( FltObjects->Instance,
FltObjects->FileObject,
Data->Iopb->Parameters.DirectoryControl.QueryDirectory.Length,
Data->Iopb->Parameters.DirectoryControl.QueryDirectory.FileInformationClass,
Data->Iopb->Parameters.DirectoryControl.QueryDirectory.FileName,
Reset,
&DirCtx->Cache);
//
// We only want to reset the cache once.
//
Reset = FALSE;
//
// There was a problem populating cache, pass up to user.
//
if (!NT_SUCCESS( Status )) {
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
}
NextEntry = NcDirEnumSelectNextEntry( DirCtx, &Offsets, IgnoreCase );
if (NextEntry == NULL) {
//
// There are no more entries.
//
break;
}
if (NcSkipName( &Offsets,
DirCtx,
RealOverlap,
&InstanceContext->Mapping,
IgnoreCase )) {
//
// This entry is the real mapping path. That means we have to mask it...
// We will say there is more room and continue.
//
MoreRoom = TRUE;
} else {
//
// We are keeping this entry!
//
try {
LastEntryStart = UserBufferOffset;
UserBufferOffset = NcCopyDirEnumEntry( UserBuffer,
UserBufferOffset,
BufferSize,
NextEntry,
&Offsets,
&MoreRoom );
} except (NcExceptionFilter( GetExceptionInformation(), TRUE )) {
Status = STATUS_INVALID_USER_BUFFER;
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
if (MoreRoom) {
NumEntriesCopied++;
}
}// end of "we are copying entry"
} while (MoreRoom &&
(Single ? (NumEntriesCopied < 1) : TRUE));
if (NumEntriesCopied > 0) {
//
// Now we know what the last entry in the user buffer is going to be.
// Set its NextEntryOffset to 0, so that the user knows its the last element.
//
try {
NcSetNextEntryOffset( Add2Ptr(UserBuffer, LastEntryStart),
&Offsets,
TRUE );
} except (NcExceptionFilter( GetExceptionInformation(), TRUE )) {
Status = STATUS_INVALID_USER_BUFFER;
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
}
}
//
// We finished copying data.
//
ReturnValue = FLT_PREOP_COMPLETE;
if (NumEntriesCopied == 0) {
if (FirstQuery) {
Status = STATUS_NO_SUCH_FILE;
} else {
Status = STATUS_NO_MORE_FILES;
}
} else {
Status = STATUS_SUCCESS;
}
ReturnValue = FLT_PREOP_COMPLETE;
goto NcEnumerateDirectoryCleanup;
NcEnumerateDirectoryCleanup:
if (ReturnValue == FLT_PREOP_COMPLETE) {
//
// We need to write back results of query.
//
Data->IoStatus.Status = Status;
if (NT_SUCCESS( Status )) {
//success
Data->IoStatus.Information = UserBufferOffset;
} else {
//failure
Data->IoStatus.Information = 0;
}
}
if (InstanceContext != NULL) {
FltReleaseContext( InstanceContext );
}
if (DirCtx != NULL) {
if (!Unlock) {
NcLockStreamHandleContext( HandleContext );
Unlock = TRUE;
}
FLT_ASSERT( DirCtx->EnumerationOutstanding );
DirCtx->EnumerationOutstanding = FALSE;
NcUnlockStreamHandleContext( HandleContext );
Unlock = FALSE;
FltReleaseContext( HandleContext );
}
FLT_ASSERT( !Unlock );
if (FileNameInformation != NULL) {
FltReleaseFileNameInformation( FileNameInformation );
}
return ReturnValue;
}
ULONG
NcCopyDirEnumEntry (
_Out_ PVOID UserBuffer,
_In_ ULONG UserOffset,
_In_ ULONG UserSize,
_Inout_ PNC_CACHE_ENTRY Entry,
_In_ PDIRECTORY_CONTROL_OFFSETS Offsets,
_Out_ PBOOLEAN Copied
)
/*++
Routine Description:
This routine copies a single enumeration result into the caller's
buffer.
Arguments:
UserBuffer - Pointer to the caller's buffer.
UserOffset - Offset within the caller's buffer that we intend to write new
results.
UserSize - Size of the caller's buffer, in bytes.
Entry - Pointer to the directory entry that we intend to return.
Offsets - Information describing the offsets for this enumeration class.
Copied - Pointer to a boolean value indicating whether this routine copied
a new entry or not.
Return Value:
The new offset in the user buffer that any future copies should use.
--*/
{
PVOID Element = Add2Ptr( Entry->Buffer, Entry->CurrentOffset );
PVOID Dest = Add2Ptr( UserBuffer, UserOffset );
ULONG ElementSize = NcGetEntrySize( Element, Offsets );
BOOLEAN LastElement = (BOOLEAN)(NcGetNextEntryOffset( Element, Offsets ) == 0);
PAGED_CODE();
if (UserSize - UserOffset >= ElementSize) {
//
// There is enough room for this element, so copy it.
//
RtlCopyMemory( Dest, Element, ElementSize );
UserOffset += ElementSize;
*Copied = TRUE;
//
// Update Entry's Offset
//
if (LastElement) {
//
// This was the last element in the entry, so we should clean the
// entry.
//
ExFreePoolWithTag( Entry->Buffer, NC_TAG );
Entry->Buffer = NULL;
Entry->CurrentOffset = 0;
//
// The last element in cached entries have a NextEntryOffset of 0,
// make sure that we report the actual next entry offset.
//
NcSetNextEntryOffset( Dest, Offsets, FALSE );
} else {
//
// Entry has more elements, update offset counter.
//
Entry->CurrentOffset += ElementSize;
}
} else {
//
// User buffer does not have enough space.
//
*Copied = FALSE;
}
return UserOffset;
}
