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1492 lines
37 KiB
1492 lines
37 KiB
/*++
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Copyright (c) 1990 Microsoft Corporation
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Module Name:
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psldt.c
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Abstract:
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This module contains code for the process and thread ldt support
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Author:
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Dave Hastings (daveh) 20 May 1991
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Notes:
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We return STATUS_SUCCESS for exceptions resulting from accessing the
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process info structures in user space. This is by design (so Markl
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tells me). By the time we reach these functions all of the parameters
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in user space have been probed, so if we get an exception it indicates
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that the user is altering portions of his address space that have been
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passed to the system.
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The nonpaged pool consumed by the Ldt is returned to the system at process
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deletion time. The process deletion handler calls PspDeleteLdt. We
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do not keep a reference to the process once the ldt is created.
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Note that the LDT must be kept in nonpaged memory because the EXIT_ALL
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macros that return from traps and interrupts pop ds (which may be an LDT
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selector) and then other registers. With interrupts disabled.
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We capture the user mode parameters into local parameters to prevent
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the possibility that the user will change them after we validate them.
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Revision History:
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--*/
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#include "psp.h"
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//
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// Internal constants
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//
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#define DESCRIPTOR_GRAN 0x00800000
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#define DESCRIPTOR_NP 0x00008000
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#define DESCRIPTOR_SYSTEM 0x00001000
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#define DESCRIPTOR_CONFORM 0x00001C00
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#define DESCRIPTOR_DPL 0x00006000
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#define DESCRIPTOR_TYPEDPL 0x00007F00
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KMUTEX LdtMutex;
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//
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// Internal subroutines
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//
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PLDT_ENTRY
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PspCreateLdt(
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IN PLDT_ENTRY Ldt,
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IN ULONG Offset,
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IN ULONG Size,
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IN ULONG AllocationSize
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);
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BOOLEAN
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PspIsDescriptorValid(
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IN PLDT_ENTRY Descriptor
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);
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(INIT, PspLdtInitialize)
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#pragma alloc_text(PAGE, NtSetLdtEntries)
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#pragma alloc_text(PAGE, PspDeleteLdt)
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#pragma alloc_text(PAGE, PspQueryLdtInformation)
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#pragma alloc_text(PAGE, PspSetLdtSize)
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#pragma alloc_text(PAGE, PspSetLdtInformation)
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#pragma alloc_text(PAGE, PspCreateLdt)
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#pragma alloc_text(PAGE, PspIsDescriptorValid)
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#pragma alloc_text(PAGE, PspQueryDescriptorThread)
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#endif
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NTSTATUS
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PspLdtInitialize(
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)
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/*++
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Routine Description:
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This routine initializes the Ldt support for the x86
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Arguments:
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None
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Return Value:
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TBS
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--*/
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{
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KeInitializeMutex( &LdtMutex, MUTEX_LEVEL_PS_LDT );
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return STATUS_SUCCESS;
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}
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NTSTATUS
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PspQueryLdtInformation(
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IN PEPROCESS Process,
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OUT PPROCESS_LDT_INFORMATION LdtInformation,
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IN ULONG LdtInformationLength,
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OUT PULONG ReturnLength
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)
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/*++
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Routine Description:
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This function performs the work for the Ldt portion of the query
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process information function. It copies the contents of the Ldt
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for the specified process into the user's buffer, up to the length
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of the buffer.
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Arguments:
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Process -- Supplies a pointer to the process to return LDT info for
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LdtInformation -- Supplies a pointer to the buffer
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ReturnLength -- Returns the number of bytes put into the buffer
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Return Value:
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TBS
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--*/
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{
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ULONG CopyLength, CopyEnd;
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NTSTATUS Status;
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ULONG HeaderLength;
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ULONG Length=0, Start=0;
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LONG MutexStatus;
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PLDTINFORMATION ProcessLdtInfo;
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PAGED_CODE();
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//
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// Verify the parameters
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//
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if (LdtInformationLength < sizeof(PROCESS_LDT_INFORMATION)) {
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return STATUS_INFO_LENGTH_MISMATCH;
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}
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//
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// This portion of the parameters may be in user space
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//
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try {
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//
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// Capture parameters
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//
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Length = LdtInformation->Length;
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Start = LdtInformation->Start;
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} except (EXCEPTION_EXECUTE_HANDLER) {
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return GetExceptionCode ();
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}
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//
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// The buffer containing the Ldt entries must be in the information
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// structure. We subtract one Ldt entry, because the structure is
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// declared to contain one.
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//
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if (LdtInformationLength - sizeof(PROCESS_LDT_INFORMATION) + sizeof(LDT_ENTRY) < Length) {
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return STATUS_INFO_LENGTH_MISMATCH;
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}
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// An Ldt entry is a processor structure, and must be 8 bytes long
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ASSERT((sizeof(LDT_ENTRY) == 8));
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//
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// The length of the structure must be an even number of Ldt entries
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//
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if (Length % sizeof(LDT_ENTRY)) {
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return STATUS_INVALID_LDT_SIZE;
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}
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//
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// The information to get from the Ldt must start on an Ldt entry
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// boundary.
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//
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if (Start % sizeof(LDT_ENTRY)) {
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return STATUS_INVALID_LDT_OFFSET;
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}
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//
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// Acquire the Ldt mutex
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//
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Status = KeWaitForSingleObject(
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&LdtMutex,
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Executive,
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KernelMode,
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FALSE,
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NULL
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);
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if ( !NT_SUCCESS(Status) ) {
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return Status;
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}
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ProcessLdtInfo = Process->LdtInformation;
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//
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// If the process has an Ldt
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//
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if (( ProcessLdtInfo) && (ProcessLdtInfo->Size )) {
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ASSERT ((ProcessLdtInfo->Ldt));
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//
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// Set the end of the copy to be the smaller of:
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// the end of the information the user requested or
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// the end of the information that is actually there
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//
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if (ProcessLdtInfo->Size < Start) {
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CopyEnd = Start;
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} else if (ProcessLdtInfo->Size - Start > Length) {
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CopyEnd = Length + Start;
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} else {
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CopyEnd = ProcessLdtInfo->Size;
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}
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CopyLength = CopyEnd - Start;
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try {
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//
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// Set the length field to the actual length of the Ldt
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//
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LdtInformation->Length = ProcessLdtInfo->Size;
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//
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// Copy the contents of the Ldt into the user's buffer
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//
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if (CopyLength) {
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RtlCopyMemory(
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&(LdtInformation->LdtEntries),
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(PCHAR)ProcessLdtInfo->Ldt + Start,
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CopyLength
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);
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}
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} except(EXCEPTION_EXECUTE_HANDLER) {
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MutexStatus = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT(( MutexStatus == 0 ));
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return GetExceptionCode ();
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}
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} else {
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//
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// There is no Ldt
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//
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CopyLength = 0;
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try {
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LdtInformation->Length = 0;
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} except(EXCEPTION_EXECUTE_HANDLER) {
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MutexStatus = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT(( MutexStatus == 0 ));
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return GetExceptionCode ();
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}
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}
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//
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// Set the length of the information returned
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//
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if ( ARGUMENT_PRESENT(ReturnLength) ) {
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try {
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HeaderLength = (PCHAR)(&(LdtInformation->LdtEntries)) -
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(PCHAR)(&(LdtInformation->Start));
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*ReturnLength = CopyLength + HeaderLength;
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} except(EXCEPTION_EXECUTE_HANDLER){
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MutexStatus = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT(( MutexStatus == 0 ));
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return GetExceptionCode ();
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}
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}
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MutexStatus = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT(( MutexStatus == 0 ));
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return STATUS_SUCCESS;
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}
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NTSTATUS
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PspSetLdtSize(
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IN PEPROCESS Process,
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IN PPROCESS_LDT_SIZE LdtSize,
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IN ULONG LdtSizeLength
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)
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/*++
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Routine Description:
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This routine changes the LDT size. It will shrink the LDT, but not
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grow it. If the LDT shrinks by 1 or more pages from its current allocation,
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the LDT will be reallocated for the new smaller size. If the allocated
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size of the LDT changes, the quota charge for the Ldt will be reduced.
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Arguments:
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Process -- Supplies a pointer to the process whose Ldt is to be sized
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LdtSize -- Supplies a pointer to the size information
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Return Value:
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TBS
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--*/
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{
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ULONG OldSize = 0, NewSize;
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LONG MutexState;
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ULONG Length=0;
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PLDT_ENTRY OldLdt = NULL;
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NTSTATUS Status;
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PLDTINFORMATION ProcessLdtInfo;
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PLDT_ENTRY Ldt;
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PAGED_CODE();
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//
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// Verify the parameters
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//
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if (LdtSizeLength != sizeof (PROCESS_LDT_SIZE)){
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return STATUS_INFO_LENGTH_MISMATCH;
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}
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//
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// The following parameters may be in user space
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//
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try {
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//
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// Capture the new Ldt length
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//
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Length = LdtSize->Length;
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} except(EXCEPTION_EXECUTE_HANDLER){
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return GetExceptionCode ();
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}
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ASSERT((sizeof(LDT_ENTRY) == 8));
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//
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// The Ldt must always be an integral number of LDT_ENTRIES
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//
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if (Length % sizeof(LDT_ENTRY)) {
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return STATUS_INVALID_LDT_SIZE;
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}
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//
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// Acquire the Ldt Mutex
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//
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Status = KeWaitForSingleObject(
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&LdtMutex,
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Executive,
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KernelMode,
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FALSE,
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NULL
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);
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if (!NT_SUCCESS (Status)) {
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return Status;
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}
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//
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// If there isn't an Ldt we can't set the size of the LDT
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//
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ProcessLdtInfo = Process->LdtInformation;
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if ((ProcessLdtInfo == NULL) || (ProcessLdtInfo->Size == 0)) {
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MutexState = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT((MutexState == 0));
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return STATUS_NO_LDT;
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}
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//
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// This function cannot be used to grow the Ldt
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//
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if (Length > ProcessLdtInfo->Size) {
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MutexState = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT((MutexState == 0));
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return STATUS_INVALID_LDT_SIZE;
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}
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//
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// Later, we will set ProcessLdtInfo->Ldt = Ldt. We may set the value
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// of Ldt in the if statement below, but there is one case where we
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// don't
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//
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Ldt = ProcessLdtInfo->Ldt;
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//
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// Adjust the size of the LDT
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//
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ProcessLdtInfo->Size = Length;
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//
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// Free some of the Ldt memory if conditions allow
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//
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if ( Length == 0 ) {
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OldSize = ProcessLdtInfo->AllocatedSize;
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OldLdt = ProcessLdtInfo->Ldt;
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ProcessLdtInfo->AllocatedSize = 0;
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Ldt = NULL;
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} else if ((ProcessLdtInfo->AllocatedSize - ProcessLdtInfo->Size) >= PAGE_SIZE) {
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OldSize = ProcessLdtInfo->AllocatedSize;
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OldLdt = ProcessLdtInfo->Ldt;
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//
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// Calculate new Ldt size (lowest integer number of pages
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// large enough)
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//
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ProcessLdtInfo->AllocatedSize = (ProcessLdtInfo->Size + PAGE_SIZE - 1)
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& ~(PAGE_SIZE - 1);
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//
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// Reallocate and copy the Ldt
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//
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Ldt = PspCreateLdt(
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ProcessLdtInfo->Ldt,
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0,
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ProcessLdtInfo->Size,
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ProcessLdtInfo->AllocatedSize
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);
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if ( Ldt == NULL ) {
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// We cannot reduce the allocation, but we can reduce the
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// Ldt selector limit (done using Ke386SetLdtProcess)
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Ldt = OldLdt;
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ProcessLdtInfo->AllocatedSize = OldSize;
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OldLdt = NULL;
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}
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}
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ProcessLdtInfo->Ldt = Ldt;
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//
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// Change the limit on the Process Ldt
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//
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Ke386SetLdtProcess(
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&(Process->Pcb),
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ProcessLdtInfo->Ldt,
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ProcessLdtInfo->Size
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);
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NewSize = ProcessLdtInfo->AllocatedSize;
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MutexState = KeReleaseMutex( &LdtMutex, FALSE );
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ASSERT((MutexState == 0));
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//
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// If we resized the Ldt, free the old one and reduce the quota charge
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//
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if (OldLdt) {
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ExFreePool( OldLdt );
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PsReturnProcessNonPagedPoolQuota (Process,
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OldSize - NewSize);
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}
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return STATUS_SUCCESS;
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}
|
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|
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|
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NTSTATUS
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PspSetLdtInformation(
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IN PEPROCESS Process,
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IN PPROCESS_LDT_INFORMATION LdtInformation,
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IN ULONG LdtInformationLength
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)
|
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|
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/*++
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|
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Routine Description:
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This function alters the ldt for a specified process. It can alter
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portions of the LDT, or the whole LDT. If an Ldt is created or
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grown, the specified process will be charged the quota for the LDT.
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Each descriptor that is set will be verified.
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|
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Arguments:
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Process -- Supplies a pointer to the process whose Ldt is to be modified
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LdtInformation -- Supplies a pointer to the information about the Ldt
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modifications
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LdtInformationLength -- Supplies the length of the LdtInformation
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structure.
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Return Value:
|
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|
|
TBS
|
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--*/
|
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{
|
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NTSTATUS Status;
|
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PLDT_ENTRY OldLdt = NULL;
|
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ULONG OldSize = 0;
|
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ULONG AllocatedSize;
|
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ULONG Size;
|
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ULONG MutexState;
|
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ULONG LdtOffset;
|
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PLDT_ENTRY CurrentDescriptor;
|
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PPROCESS_LDT_INFORMATION LdtInfo=NULL;
|
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PLDTINFORMATION ProcessLdtInfo;
|
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PLDT_ENTRY Ldt;
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|
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PAGED_CODE();
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|
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if (LdtInformationLength < sizeof (PROCESS_LDT_INFORMATION)) {
|
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return STATUS_INFO_LENGTH_MISMATCH;
|
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}
|
|
|
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Status = STATUS_SUCCESS;
|
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LdtInfo = ExAllocatePoolWithTag (NonPagedPool,
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LdtInformationLength,
|
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'dLsP');
|
|
|
|
if (LdtInfo == NULL) {
|
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return STATUS_INSUFFICIENT_RESOURCES;
|
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}
|
|
|
|
//
|
|
// alocate a local buffer to capture the ldt information to
|
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//
|
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try {
|
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//
|
|
// Copy the information the user is supplying
|
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//
|
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RtlCopyMemory (LdtInfo,
|
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LdtInformation,
|
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LdtInformationLength);
|
|
|
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} except (EXCEPTION_EXECUTE_HANDLER) {
|
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ExFreePool (LdtInfo);
|
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Status = GetExceptionCode ();
|
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return Status;
|
|
}
|
|
|
|
//
|
|
// Verify that the Start and Length are plausible
|
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//
|
|
if (LdtInfo->Start & 0xFFFF0000) {
|
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ExFreePool (LdtInfo);
|
|
return STATUS_INVALID_LDT_OFFSET;
|
|
}
|
|
|
|
if (LdtInfo->Length & 0xFFFF0000) {
|
|
ExFreePool (LdtInfo);
|
|
return STATUS_INVALID_LDT_SIZE;
|
|
}
|
|
|
|
//
|
|
// Insure that the buffer it large enough to contain the specified number
|
|
// of selectors.
|
|
//
|
|
if (LdtInformationLength - sizeof (PROCESS_LDT_INFORMATION) + sizeof (LDT_ENTRY) < LdtInfo->Length) {
|
|
ExFreePool (LdtInfo);
|
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return STATUS_INFO_LENGTH_MISMATCH;
|
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}
|
|
|
|
//
|
|
// The info to set must be an integral number of selectors
|
|
//
|
|
if (LdtInfo->Length % sizeof (LDT_ENTRY)) {
|
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ExFreePool (LdtInfo);
|
|
return STATUS_INVALID_LDT_SIZE;
|
|
}
|
|
|
|
//
|
|
// The beginning of the info must be on a selector boundary
|
|
//
|
|
if (LdtInfo->Start % sizeof (LDT_ENTRY)) {
|
|
ExFreePool (LdtInfo);
|
|
return STATUS_INVALID_LDT_OFFSET;
|
|
}
|
|
|
|
//
|
|
// Verify all of the descriptors.
|
|
//
|
|
|
|
for (CurrentDescriptor = LdtInfo->LdtEntries;
|
|
(PCHAR)CurrentDescriptor < (PCHAR)LdtInfo->LdtEntries + LdtInfo->Length;
|
|
CurrentDescriptor++) {
|
|
if (!PspIsDescriptorValid (CurrentDescriptor)) {
|
|
ExFreePool (LdtInfo);
|
|
return STATUS_INVALID_LDT_DESCRIPTOR;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Acquire the Ldt Mutex
|
|
//
|
|
|
|
Status = KeWaitForSingleObject (&LdtMutex,
|
|
Executive,
|
|
KernelMode,
|
|
FALSE,
|
|
NULL);
|
|
if (!NT_SUCCESS (Status)) {
|
|
ExFreePool (LdtInfo);
|
|
return Status;
|
|
}
|
|
|
|
ProcessLdtInfo = Process->LdtInformation;
|
|
|
|
//
|
|
// If the process doen't have an Ldt information structure, allocate
|
|
// one and attach it to the process
|
|
//
|
|
if (ProcessLdtInfo == NULL) {
|
|
ProcessLdtInfo = ExAllocatePoolWithTag (NonPagedPool,
|
|
sizeof(LDTINFORMATION),
|
|
'dLsP');
|
|
if (ProcessLdtInfo == NULL) {
|
|
goto SetInfoCleanup;
|
|
}
|
|
Process->LdtInformation = ProcessLdtInfo;
|
|
RtlZeroMemory (ProcessLdtInfo, sizeof (LDTINFORMATION));
|
|
}
|
|
|
|
//
|
|
// If we are supposed to remove the LDT
|
|
//
|
|
if (LdtInfo->Length == 0) {
|
|
|
|
//
|
|
// Remove the process' Ldt
|
|
//
|
|
|
|
if (ProcessLdtInfo->Ldt) {
|
|
OldSize = ProcessLdtInfo->AllocatedSize;
|
|
OldLdt = ProcessLdtInfo->Ldt;
|
|
|
|
ProcessLdtInfo->AllocatedSize = 0;
|
|
ProcessLdtInfo->Size = 0;
|
|
ProcessLdtInfo->Ldt = NULL;
|
|
|
|
Ke386SetLdtProcess (&Process->Pcb,
|
|
NULL,
|
|
0);
|
|
|
|
PsReturnProcessNonPagedPoolQuota (Process, OldSize);
|
|
}
|
|
|
|
|
|
} else if (ProcessLdtInfo->Ldt == NULL) {
|
|
|
|
//
|
|
// Create a new Ldt for the process
|
|
//
|
|
|
|
//
|
|
// Allocate an integral number of pages for the LDT.
|
|
//
|
|
|
|
ASSERT(((PAGE_SIZE % 2) == 0));
|
|
|
|
AllocatedSize = (LdtInfo->Start + LdtInfo->Length + PAGE_SIZE - 1) &
|
|
~(PAGE_SIZE - 1);
|
|
|
|
Size = LdtInfo->Start + LdtInfo->Length;
|
|
|
|
Ldt = PspCreateLdt (LdtInfo->LdtEntries,
|
|
LdtInfo->Start,
|
|
Size,
|
|
AllocatedSize);
|
|
|
|
if (Ldt == NULL) {
|
|
Status = STATUS_INSUFFICIENT_RESOURCES;
|
|
goto SetInfoCleanup;
|
|
}
|
|
|
|
Status = PsChargeProcessNonPagedPoolQuota (Process,
|
|
AllocatedSize);
|
|
|
|
if (!NT_SUCCESS (Status)) {
|
|
ExFreePool (Ldt);
|
|
Ldt = NULL;
|
|
goto SetInfoCleanup;
|
|
}
|
|
|
|
ProcessLdtInfo->Ldt = Ldt;
|
|
ProcessLdtInfo->Size = Size;
|
|
ProcessLdtInfo->AllocatedSize = AllocatedSize;
|
|
Ke386SetLdtProcess (&Process->Pcb,
|
|
ProcessLdtInfo->Ldt,
|
|
ProcessLdtInfo->Size);
|
|
|
|
|
|
} else if (LdtInfo->Length + LdtInfo->Start > ProcessLdtInfo->Size) {
|
|
|
|
//
|
|
// Grow the process' Ldt
|
|
//
|
|
|
|
if (LdtInfo->Length + LdtInfo->Start > ProcessLdtInfo->AllocatedSize) {
|
|
|
|
//
|
|
// Current Ldt allocation is not large enough, so create a
|
|
// new larger Ldt
|
|
//
|
|
|
|
OldSize = ProcessLdtInfo->AllocatedSize;
|
|
|
|
Size = LdtInfo->Start + LdtInfo->Length;
|
|
AllocatedSize = (Size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
|
|
|
|
Ldt = PspCreateLdt (ProcessLdtInfo->Ldt,
|
|
0,
|
|
OldSize,
|
|
AllocatedSize);
|
|
|
|
if (Ldt == NULL) {
|
|
Status = STATUS_INSUFFICIENT_RESOURCES;
|
|
goto SetInfoCleanup;
|
|
}
|
|
|
|
|
|
Status = PsChargeProcessNonPagedPoolQuota (Process,
|
|
AllocatedSize);
|
|
|
|
if (!NT_SUCCESS (Status)) {
|
|
ExFreePool (Ldt);
|
|
Ldt = NULL;
|
|
goto SetInfoCleanup;
|
|
}
|
|
PsReturnProcessNonPagedPoolQuota (Process,
|
|
OldSize);
|
|
|
|
//
|
|
// Swap Ldt information
|
|
//
|
|
OldLdt = ProcessLdtInfo->Ldt;
|
|
ProcessLdtInfo->Ldt = Ldt;
|
|
ProcessLdtInfo->Size = Size;
|
|
ProcessLdtInfo->AllocatedSize = AllocatedSize;
|
|
|
|
//
|
|
// Put new selectors into the new ldt
|
|
//
|
|
RtlCopyMemory ((PCHAR)(ProcessLdtInfo->Ldt) + LdtInfo->Start,
|
|
LdtInfo->LdtEntries,
|
|
LdtInfo->Length);
|
|
|
|
Ke386SetLdtProcess (&Process->Pcb,
|
|
ProcessLdtInfo->Ldt,
|
|
ProcessLdtInfo->Size);
|
|
|
|
|
|
} else {
|
|
|
|
//
|
|
// Current Ldt allocation is large enough
|
|
//
|
|
|
|
ProcessLdtInfo->Size = LdtInfo->Length + LdtInfo->Start;
|
|
|
|
Ke386SetLdtProcess (&Process->Pcb,
|
|
ProcessLdtInfo->Ldt,
|
|
ProcessLdtInfo->Size);
|
|
|
|
//
|
|
// Change the selectors in the table
|
|
//
|
|
for (LdtOffset = LdtInfo->Start, CurrentDescriptor = LdtInfo->LdtEntries;
|
|
LdtOffset < LdtInfo->Start + LdtInfo->Length;
|
|
LdtOffset += sizeof(LDT_ENTRY), CurrentDescriptor++) {
|
|
|
|
Ke386SetDescriptorProcess (&Process->Pcb,
|
|
LdtOffset,
|
|
*CurrentDescriptor);
|
|
}
|
|
}
|
|
} else {
|
|
|
|
//
|
|
// Simply changing some selectors
|
|
//
|
|
|
|
for (LdtOffset = LdtInfo->Start, CurrentDescriptor = LdtInfo->LdtEntries;
|
|
LdtOffset < LdtInfo->Start + LdtInfo->Length;
|
|
LdtOffset += sizeof(LDT_ENTRY), CurrentDescriptor++) {
|
|
|
|
Ke386SetDescriptorProcess (&Process->Pcb,
|
|
LdtOffset,
|
|
*CurrentDescriptor);
|
|
}
|
|
Status = STATUS_SUCCESS;
|
|
}
|
|
|
|
|
|
SetInfoCleanup:
|
|
|
|
MutexState = KeReleaseMutex (&LdtMutex, FALSE);
|
|
ASSERT ((MutexState == 0));
|
|
|
|
if (OldLdt != NULL) {
|
|
ExFreePool (OldLdt);
|
|
}
|
|
|
|
if (LdtInfo != NULL) {
|
|
ExFreePool (LdtInfo);
|
|
}
|
|
|
|
return Status;
|
|
}
|
|
|
|
PLDT_ENTRY
|
|
PspCreateLdt (
|
|
IN PLDT_ENTRY Ldt,
|
|
IN ULONG Offset,
|
|
IN ULONG Size,
|
|
IN ULONG AllocationSize
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine allocates space in nonpaged pool for an LDT, and copies the
|
|
specified selectors into it. IT DOES NOT VALIDATE THE SELECTORS.
|
|
Selector validation must be done before calling this routine. IT
|
|
DOES NOT CHARGE THE QUOTA FOR THE LDT.
|
|
|
|
Arguments:
|
|
|
|
Ldt -- Supplies a pointer to the descriptors to be put into the Ldt.
|
|
Offset -- Supplies the offset in the LDT to copy the descriptors to.
|
|
Size -- Supplies the actualsize of the new Ldt
|
|
AllocationSize -- Supplies the size to allocate
|
|
|
|
Return Value:
|
|
|
|
Pointer to the new Ldt
|
|
--*/
|
|
{
|
|
PLDT_ENTRY NewLdt;
|
|
|
|
PAGED_CODE();
|
|
|
|
ASSERT ((AllocationSize >= Size));
|
|
ASSERT (((Size % sizeof(LDT_ENTRY)) == 0));
|
|
|
|
NewLdt = ExAllocatePoolWithTag (NonPagedPool, AllocationSize, 'dLsP');
|
|
if (NewLdt != NULL) {
|
|
RtlZeroMemory (NewLdt, AllocationSize);
|
|
RtlCopyMemory ((PCHAR)NewLdt + Offset, Ldt, Size - Offset);
|
|
}
|
|
|
|
return NewLdt;
|
|
}
|
|
|
|
|
|
|
|
BOOLEAN
|
|
PspIsDescriptorValid(
|
|
IN PLDT_ENTRY Descriptor
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This function determines if the supplied descriptor is valid to put
|
|
into a process Ldt. For the descriptor to be valid it must have the
|
|
following characteristics:
|
|
|
|
Base < MM_HIGHEST_USER_ADDRESS
|
|
Base + Limit < MM_HIGHEST_USER_ADDRESS
|
|
Type must be
|
|
ReadWrite, ReadOnly, ExecuteRead, ExecuteOnly, or Invalid
|
|
big or small
|
|
normal or grow down
|
|
Not a system descriptor (system bit is 1 == application)
|
|
This rules out all gates, etc
|
|
Not conforming
|
|
DPL must be 3
|
|
|
|
Arguments:
|
|
|
|
Descriptor -- Supplies a pointer to the descriptor to check
|
|
|
|
Return Value:
|
|
|
|
True if the descriptor is valid (note: valid to put into an LDT. This
|
|
includes Invalid descriptors)
|
|
False if not
|
|
--*/
|
|
|
|
{
|
|
ULONG Base;
|
|
ULONG Limit;
|
|
|
|
PAGED_CODE();
|
|
|
|
//
|
|
// if descriptor is an invalid descriptor
|
|
//
|
|
|
|
if ((Descriptor->HighWord.Bits.Type == 0) &&
|
|
(Descriptor->HighWord.Bits.Dpl == 0)) {
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
Base = Descriptor->BaseLow | (Descriptor->HighWord.Bytes.BaseMid << 16) |
|
|
(Descriptor->HighWord.Bytes.BaseHi << 24);
|
|
|
|
Limit = Descriptor->LimitLow | (Descriptor->HighWord.Bits.LimitHi << 16);
|
|
|
|
//
|
|
// Only have to check for present selectors
|
|
//
|
|
if (Descriptor->HighWord.Bits.Pres) {
|
|
ULONG ActualLimit;
|
|
|
|
if ((Descriptor->HighWord.Bits.Type&0x14) == 0x14) {
|
|
if (Descriptor->HighWord.Bits.Default_Big == 1) {
|
|
ActualLimit = 0xFFFFFFFF;
|
|
} else {
|
|
ActualLimit = 0xFFFF;
|
|
}
|
|
} else if (Descriptor->HighWord.Bits.Granularity == 0) {
|
|
ActualLimit = Limit;
|
|
} else {
|
|
ActualLimit = (Limit<<12) + 0xFFF;
|
|
}
|
|
|
|
//
|
|
// See if the segment extends into the kernel address space.
|
|
//
|
|
if (Base > Base + ActualLimit ||
|
|
((PVOID)(Base + ActualLimit) > MM_HIGHEST_USER_ADDRESS)) {
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// Don't let the reserved field be set.
|
|
//
|
|
if (Descriptor->HighWord.Bits.Reserved_0 != 0) {
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// if descriptor is a system descriptor (which includes gates)
|
|
// if bit 4 of the Type field is 0, then it's a system descriptor,
|
|
// and we don't like it.
|
|
//
|
|
|
|
if (!(Descriptor->HighWord.Bits.Type & 0x10)) {
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// if descriptor is conforming code
|
|
//
|
|
|
|
if (((Descriptor->HighWord.Bits.Type & 0x18) == 0x18) &&
|
|
(Descriptor->HighWord.Bits.Type & 0x4)) {
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// if Dpl is not 3
|
|
//
|
|
|
|
if (Descriptor->HighWord.Bits.Dpl != 3) {
|
|
return FALSE;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
NTSTATUS
|
|
PspQueryDescriptorThread (
|
|
PETHREAD Thread,
|
|
PVOID ThreadInformation,
|
|
ULONG ThreadInformationLength,
|
|
PULONG ReturnLength
|
|
)
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This function retrieves a descriptor table entry for the specified thread.
|
|
This entry may be in either the Gdt or the Ldt, as specfied by the
|
|
supplied selector
|
|
|
|
Arguments:
|
|
|
|
Thread -- Supplies a pointer to the thread.
|
|
ThreadInformation -- Supplies information on the descriptor.
|
|
ThreadInformationLength -- Supplies the length of the information.
|
|
ReturnLength -- Returns the number of bytes returned.
|
|
|
|
Return Value:
|
|
|
|
TBS
|
|
--*/
|
|
{
|
|
DESCRIPTOR_TABLE_ENTRY DescriptorEntry={0};
|
|
PEPROCESS Process;
|
|
LONG MutexState;
|
|
NTSTATUS Status;
|
|
|
|
PAGED_CODE();
|
|
|
|
ASSERT( sizeof(KGDTENTRY) == sizeof(LDT_ENTRY) );
|
|
|
|
//
|
|
// Verify parameters
|
|
//
|
|
|
|
if ( ThreadInformationLength != sizeof(DESCRIPTOR_TABLE_ENTRY) ) {
|
|
return STATUS_INFO_LENGTH_MISMATCH;
|
|
}
|
|
|
|
try {
|
|
DescriptorEntry = *(PDESCRIPTOR_TABLE_ENTRY)ThreadInformation;
|
|
} except(EXCEPTION_EXECUTE_HANDLER){
|
|
return GetExceptionCode ();
|
|
}
|
|
|
|
|
|
Status = STATUS_SUCCESS;
|
|
|
|
//
|
|
// If its a Gdt entry, let the kernel find it for us
|
|
//
|
|
|
|
if ( !(DescriptorEntry.Selector & SELECTOR_TABLE_INDEX) ) {
|
|
|
|
if ( (DescriptorEntry.Selector & 0xFFFFFFF8) >= KGDT_NUMBER * sizeof(KGDTENTRY) ) {
|
|
|
|
return STATUS_ACCESS_VIOLATION;
|
|
}
|
|
|
|
try {
|
|
Ke386GetGdtEntryThread (&Thread->Tcb,
|
|
DescriptorEntry.Selector & 0xFFFFFFF8,
|
|
(PKGDTENTRY) &(((PDESCRIPTOR_TABLE_ENTRY)ThreadInformation)->Descriptor));
|
|
if (ARGUMENT_PRESENT(ReturnLength) ) {
|
|
*ReturnLength = sizeof(LDT_ENTRY);
|
|
}
|
|
} except(EXCEPTION_EXECUTE_HANDLER) {
|
|
return GetExceptionCode ();
|
|
}
|
|
} else {
|
|
|
|
//
|
|
// it's an Ldt entry, so copy it from the ldt
|
|
//
|
|
|
|
Process = THREAD_TO_PROCESS (Thread);
|
|
|
|
//
|
|
// Acquire the Ldt Mutex
|
|
//
|
|
|
|
Status = KeWaitForSingleObject (&LdtMutex,
|
|
Executive,
|
|
KernelMode,
|
|
FALSE,
|
|
NULL);
|
|
if (!NT_SUCCESS (Status)) {
|
|
return Status;
|
|
}
|
|
|
|
if ( Process->LdtInformation == NULL ) {
|
|
|
|
// If there is no Ldt
|
|
Status = STATUS_NO_LDT;
|
|
|
|
} else if ( (DescriptorEntry.Selector & 0xFFFFFFF8) >=
|
|
((PLDTINFORMATION)(Process->LdtInformation))->Size ) {
|
|
|
|
// Else If the selector is outside the table
|
|
Status = STATUS_ACCESS_VIOLATION;
|
|
|
|
} else try {
|
|
|
|
// Else return the contents of the descriptor
|
|
RtlCopyMemory (&(((PDESCRIPTOR_TABLE_ENTRY)ThreadInformation)->Descriptor),
|
|
(PCHAR)(((PLDTINFORMATION)(Process->LdtInformation))->Ldt) +
|
|
(DescriptorEntry.Selector & 0xFFFFFFF8),
|
|
sizeof(LDT_ENTRY));
|
|
|
|
if (ARGUMENT_PRESENT(ReturnLength)) {
|
|
*ReturnLength = sizeof(LDT_ENTRY);
|
|
}
|
|
|
|
} except(EXCEPTION_EXECUTE_HANDLER) {
|
|
Status = GetExceptionCode ();
|
|
}
|
|
|
|
MutexState = KeReleaseMutex (&LdtMutex, FALSE);
|
|
ASSERT ((MutexState == 0));
|
|
}
|
|
|
|
return Status;
|
|
}
|
|
|
|
VOID
|
|
PspDeleteLdt(
|
|
IN PEPROCESS Process
|
|
)
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine frees the nonpaged pool associated with a process' Ldt, if
|
|
it has one.
|
|
|
|
Arguments:
|
|
|
|
Process -- Supplies a pointer to the process
|
|
|
|
Return Value:
|
|
|
|
None
|
|
--*/
|
|
{
|
|
PLDTINFORMATION LdtInformation;
|
|
|
|
PAGED_CODE();
|
|
|
|
LdtInformation = Process->LdtInformation;
|
|
if (LdtInformation != NULL) {
|
|
if (LdtInformation->Ldt != NULL) {
|
|
PsReturnProcessNonPagedPoolQuota (Process, LdtInformation->AllocatedSize);
|
|
ExFreePool (LdtInformation->Ldt);
|
|
}
|
|
ExFreePool( LdtInformation );
|
|
}
|
|
}
|
|
|
|
NTSTATUS
|
|
NtSetLdtEntries(
|
|
IN ULONG Selector0,
|
|
IN ULONG Entry0Low,
|
|
IN ULONG Entry0Hi,
|
|
IN ULONG Selector1,
|
|
IN ULONG Entry1Low,
|
|
IN ULONG Entry1Hi
|
|
)
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine sets up to two selectors in the current process's LDT.
|
|
The LDT will be grown as necessary. A selector value of 0 indicates
|
|
that the specified selector was not passed (allowing the setting of
|
|
a single selector).
|
|
|
|
Arguments:
|
|
|
|
Selector0 -- Supplies the number of the first descriptor to set
|
|
Entry0Low -- Supplies the low 32 bits of the descriptor
|
|
Entry0Hi -- Supplies the high 32 bits of the descriptor
|
|
Selector1 -- Supplies the number of the first descriptor to set
|
|
Entry1Low -- Supplies the low 32 bits of the descriptor
|
|
Entry1Hi -- Supplies the high 32 bits of the descriptor
|
|
|
|
Return Value:
|
|
|
|
TBS
|
|
--*/
|
|
|
|
{
|
|
ULONG LdtSize, AllocatedSize;
|
|
NTSTATUS Status;
|
|
PEPROCESS Process;
|
|
LDT_ENTRY Descriptor[2];
|
|
PLDT_ENTRY Ldt, OldLdt;
|
|
PLDTINFORMATION ProcessLdtInformation;
|
|
LONG MutexState;
|
|
ULONG Selector1Index;
|
|
|
|
PAGED_CODE();
|
|
|
|
//
|
|
// Verify the selectors. We do not allow selectors that point into
|
|
// Kernel space, system selectors, or conforming code selectors
|
|
//
|
|
|
|
//
|
|
// Verify the selectors
|
|
//
|
|
if ((Selector0 & 0xFFFF0000) || (Selector1 & 0xFFFF0000)) {
|
|
return STATUS_INVALID_LDT_DESCRIPTOR;
|
|
}
|
|
|
|
// Change the selector values to indexes into the LDT
|
|
|
|
Selector0 = Selector0 & ~(RPL_MASK | SELECTOR_TABLE_INDEX);
|
|
Selector1 = Selector1 & ~(RPL_MASK | SELECTOR_TABLE_INDEX);
|
|
|
|
|
|
//
|
|
// Verify descriptor 0
|
|
//
|
|
|
|
Selector1Index = 0;
|
|
if (Selector0) {
|
|
|
|
Selector1Index = 1;
|
|
|
|
*((PULONG)(&Descriptor[0])) = Entry0Low;
|
|
*(((PULONG)(&Descriptor[0])) + 1) = Entry0Hi;
|
|
|
|
//
|
|
// Validate the descriptor
|
|
//
|
|
if (!PspIsDescriptorValid (&Descriptor[0])) {
|
|
return STATUS_INVALID_LDT_DESCRIPTOR;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Verify descriptor 1
|
|
//
|
|
|
|
if (Selector1) {
|
|
*((PULONG)(&Descriptor[Selector1Index])) = Entry1Low;
|
|
*(((PULONG)(&Descriptor[Selector1Index])) + 1) = Entry1Hi;
|
|
|
|
//
|
|
// Validate the descriptor
|
|
//
|
|
if (!PspIsDescriptorValid (&Descriptor[Selector1Index])) {
|
|
return STATUS_INVALID_LDT_DESCRIPTOR;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Figure out how large the LDT needs to be
|
|
//
|
|
|
|
if (Selector0 > Selector1) {
|
|
LdtSize = Selector0 + sizeof(LDT_ENTRY);
|
|
} else {
|
|
LdtSize = Selector1 + sizeof(LDT_ENTRY);
|
|
}
|
|
|
|
Process = PsGetCurrentProcess();
|
|
|
|
//
|
|
// Acquire the LDT mutex.
|
|
//
|
|
|
|
Status = KeWaitForSingleObject(
|
|
&LdtMutex,
|
|
Executive,
|
|
KernelMode,
|
|
FALSE,
|
|
NULL
|
|
);
|
|
if (!NT_SUCCESS (Status)) {
|
|
return Status;
|
|
}
|
|
|
|
ProcessLdtInformation = Process->LdtInformation;
|
|
|
|
//
|
|
// Most of the time, the process will already have an LDT, and it
|
|
// will be large enough. for this, we just set the descriptors and
|
|
// return
|
|
//
|
|
|
|
if (ProcessLdtInformation) {
|
|
|
|
//
|
|
// If the LDT descriptor does not have to be modified.
|
|
//
|
|
if (ProcessLdtInformation->Size >= LdtSize) {
|
|
if (Selector0) {
|
|
|
|
Ke386SetDescriptorProcess(
|
|
&(Process->Pcb),
|
|
Selector0,
|
|
Descriptor[0]
|
|
);
|
|
}
|
|
|
|
if (Selector1) {
|
|
|
|
Ke386SetDescriptorProcess(
|
|
&(Process->Pcb),
|
|
Selector1,
|
|
Descriptor[Selector1Index]
|
|
);
|
|
}
|
|
|
|
MutexState = KeReleaseMutex( &LdtMutex, FALSE );
|
|
ASSERT(( MutexState == 0 ));
|
|
return STATUS_SUCCESS;
|
|
|
|
//
|
|
// Else if the Ldt will fit in the memory currently allocated
|
|
//
|
|
} else if (ProcessLdtInformation->AllocatedSize >= LdtSize) {
|
|
|
|
//
|
|
// First remove the LDT. This will allow us to edit the memory.
|
|
// We will then put the LDT back. Since we have to change the
|
|
// limit anyway, it would take two calls to the kernel ldt
|
|
// management minimum to set the descriptors. Each of those calls
|
|
// would stall all of the processors in an MP system. If we
|
|
// didn't remove the ldt first, and we were setting two descriptors,
|
|
// we would have to call the LDT management 3 times (once per
|
|
// descriptor, and once to change the limit of the LDT).
|
|
//
|
|
|
|
Ke386SetLdtProcess(
|
|
&(Process->Pcb),
|
|
NULL,
|
|
0L
|
|
);
|
|
|
|
//
|
|
// Set the Descriptors in the LDT
|
|
//
|
|
if (Selector0) {
|
|
*((PLDT_ENTRY) &ProcessLdtInformation->Ldt[Selector0/sizeof(LDT_ENTRY)]) = Descriptor[0];
|
|
}
|
|
|
|
if (Selector1) {
|
|
*((PLDT_ENTRY) &ProcessLdtInformation->Ldt[Selector1/sizeof(LDT_ENTRY)]) = Descriptor[Selector1Index];
|
|
}
|
|
|
|
//
|
|
// Set the LDT for the process
|
|
//
|
|
|
|
ProcessLdtInformation->Size = LdtSize;
|
|
|
|
Ke386SetLdtProcess(
|
|
&(Process->Pcb),
|
|
ProcessLdtInformation->Ldt,
|
|
ProcessLdtInformation->Size
|
|
);
|
|
|
|
MutexState = KeReleaseMutex (&LdtMutex, FALSE);
|
|
ASSERT ((MutexState == 0));
|
|
return STATUS_SUCCESS;
|
|
//
|
|
// Otherwise, we have to grow the LDT allocation
|
|
//
|
|
}
|
|
}
|
|
|
|
//
|
|
// If the process does not yet have an LDT information structure,
|
|
// allocate and attach one.
|
|
//
|
|
|
|
OldLdt = NULL;
|
|
|
|
if (!Process->LdtInformation) {
|
|
ProcessLdtInformation = ExAllocatePoolWithTag (NonPagedPool,
|
|
sizeof(LDTINFORMATION),
|
|
'dLsP');
|
|
if (ProcessLdtInformation == NULL) {
|
|
goto SetLdtEntriesCleanup;
|
|
}
|
|
Process->LdtInformation = ProcessLdtInformation;
|
|
ProcessLdtInformation->Size = 0L;
|
|
ProcessLdtInformation->AllocatedSize = 0L;
|
|
ProcessLdtInformation->Ldt = NULL;
|
|
}
|
|
|
|
//
|
|
// Now, we either need to create or grow an LDT, so allocate some
|
|
// memory, and copy as necessary
|
|
//
|
|
|
|
AllocatedSize = (LdtSize + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
|
|
|
|
Ldt = ExAllocatePoolWithTag (NonPagedPool,
|
|
AllocatedSize,
|
|
'dLsP');
|
|
|
|
if (Ldt) {
|
|
RtlZeroMemory (Ldt,
|
|
AllocatedSize);
|
|
} else {
|
|
goto SetLdtEntriesCleanup;
|
|
}
|
|
|
|
|
|
if (ProcessLdtInformation->Ldt) {
|
|
//
|
|
// copy the contents of the old ldt
|
|
//
|
|
RtlCopyMemory (Ldt,
|
|
ProcessLdtInformation->Ldt,
|
|
ProcessLdtInformation->Size);
|
|
|
|
Status = PsChargeProcessNonPagedPoolQuota (Process,
|
|
AllocatedSize);
|
|
if (!NT_SUCCESS (Status)) {
|
|
ExFreePool (Ldt);
|
|
Ldt = NULL;
|
|
} else {
|
|
PsReturnProcessNonPagedPoolQuota (Process,
|
|
ProcessLdtInformation->AllocatedSize);
|
|
}
|
|
|
|
if (Ldt == NULL) {
|
|
goto SetLdtEntriesCleanup;
|
|
}
|
|
|
|
} else {
|
|
Status = PsChargeProcessNonPagedPoolQuota (Process,
|
|
AllocatedSize);
|
|
if (!NT_SUCCESS (Status)) {
|
|
ExFreePool (Ldt);
|
|
Ldt = NULL;
|
|
}
|
|
|
|
if (Ldt == NULL) {
|
|
goto SetLdtEntriesCleanup;
|
|
}
|
|
}
|
|
|
|
OldLdt = ProcessLdtInformation->Ldt;
|
|
ProcessLdtInformation->Size = LdtSize;
|
|
ProcessLdtInformation->AllocatedSize = AllocatedSize;
|
|
ProcessLdtInformation->Ldt = Ldt;
|
|
|
|
//
|
|
// Set the descriptors in the LDT
|
|
//
|
|
|
|
if (Selector0) {
|
|
*((PLDT_ENTRY) &ProcessLdtInformation->Ldt[Selector0/sizeof(LDT_ENTRY)]) = Descriptor[0];
|
|
}
|
|
|
|
if (Selector1) {
|
|
*((PLDT_ENTRY) &ProcessLdtInformation->Ldt[Selector1/sizeof(LDT_ENTRY)]) = Descriptor[Selector1Index];
|
|
}
|
|
|
|
//
|
|
// Set the LDT for the process
|
|
//
|
|
|
|
Ke386SetLdtProcess (&Process->Pcb,
|
|
ProcessLdtInformation->Ldt,
|
|
ProcessLdtInformation->Size);
|
|
|
|
//
|
|
// Cleanup and exit
|
|
//
|
|
|
|
Status = STATUS_SUCCESS;
|
|
|
|
SetLdtEntriesCleanup:
|
|
|
|
if (OldLdt) {
|
|
ExFreePool(OldLdt);
|
|
}
|
|
|
|
MutexState = KeReleaseMutex (&LdtMutex, FALSE);
|
|
ASSERT (MutexState == 0);
|
|
return Status;
|
|
}
|