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/*++
Copyright (c) 2024 Microsoft Corporation All Rights Reserved
Module Name:
kasantrigger.c
Abstract:
The purpose of this driver is to demonstrate how KASAN detects illegal
memory accesses.
Environment:
Kernel mode only.
--*/
#include <ntddk.h>
#include <string.h>
#include "kasantrigger.h"
#define NT_DEVICE_NAME L"\\Device\\KASANTRIGGER"
#define DOS_DEVICE_NAME L"\\DosDevices\\KasanTrigger"
DRIVER_INITIALIZE DriverEntry;
_Dispatch_type_(IRP_MJ_CREATE)
_Dispatch_type_(IRP_MJ_CLOSE)
DRIVER_DISPATCH KasanTriggerCreateClose;
_Dispatch_type_(IRP_MJ_DEVICE_CONTROL)
DRIVER_DISPATCH KasanTriggerDeviceControl;
DRIVER_UNLOAD KasanTriggerUnloadDriver;
#ifdef ALLOC_PRAGMA
#pragma alloc_text(INIT, DriverEntry)
#pragma alloc_text(PAGE, KasanTriggerCreateClose)
#pragma alloc_text(PAGE, KasanTriggerDeviceControl)
#pragma alloc_text(PAGE, KasanTriggerUnloadDriver)
#endif
// -----------------------------------------------------------------------------
UCHAR GlobalVariable[KASANTRIGGER_ARRAY_SIZE];
static
UCHAR
TriggerOobrStack(
_In_ ULONG Index
)
{
UCHAR StackVariable[KASANTRIGGER_ARRAY_SIZE];
//
// This copy is only here to force the compiler not to optimize out the
// stack variable.
//
RtlCopyMemory(StackVariable, GlobalVariable, KASANTRIGGER_ARRAY_SIZE);
//
// WARNING: this is an intentionally INCORRECT code!
//
return StackVariable[Index];
}
static
UCHAR
TriggerOobrGlobal(
_In_ ULONG Index
)
{
//
// WARNING: this is an intentionally INCORRECT code!
//
return GlobalVariable[Index];
}
static
UCHAR
TriggerOobrHeap(
_In_ ULONG Index
)
{
PCHAR buffer;
UCHAR retVal;
buffer = ExAllocatePool2(POOL_FLAG_PAGED, KASANTRIGGER_ARRAY_SIZE, 'mDaK');
if (buffer == NULL) {
return 0;
}
//
// WARNING: this is an intentionally INCORRECT code!
//
retVal = buffer[Index];
ExFreePool(buffer);
return retVal;
}
// -----------------------------------------------------------------------------
NTSTATUS
DriverEntry(
_In_ PDRIVER_OBJECT DriverObject,
_In_ PUNICODE_STRING RegistryPath
)
{
NTSTATUS ntStatus;
UNICODE_STRING ntUnicodeString;
UNICODE_STRING ntWin32NameString;
PDEVICE_OBJECT deviceObject;
UNREFERENCED_PARAMETER(RegistryPath);
RtlInitUnicodeString(&ntUnicodeString, NT_DEVICE_NAME);
ntStatus = IoCreateDevice(DriverObject,
0,
&ntUnicodeString,
FILE_DEVICE_UNKNOWN,
FILE_DEVICE_SECURE_OPEN,
FALSE,
&deviceObject);
if (!NT_SUCCESS(ntStatus)) {
return ntStatus;
}
DriverObject->MajorFunction[IRP_MJ_CREATE] = KasanTriggerCreateClose;
DriverObject->MajorFunction[IRP_MJ_CLOSE] = KasanTriggerCreateClose;
DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = KasanTriggerDeviceControl;
DriverObject->DriverUnload = KasanTriggerUnloadDriver;
RtlInitUnicodeString(&ntWin32NameString, DOS_DEVICE_NAME);
ntStatus = IoCreateSymbolicLink(&ntWin32NameString, &ntUnicodeString);
if (!NT_SUCCESS(ntStatus)) {
IoDeleteDevice(deviceObject);
}
return ntStatus;
}
NTSTATUS
KasanTriggerCreateClose(
PDEVICE_OBJECT DeviceObject,
PIRP Irp
)
{
UNREFERENCED_PARAMETER(DeviceObject);
PAGED_CODE();
Irp->IoStatus.Status = STATUS_SUCCESS;
Irp->IoStatus.Information = 0;
IoCompleteRequest(Irp, IO_NO_INCREMENT);
return STATUS_SUCCESS;
}
VOID
KasanTriggerUnloadDriver(
_In_ PDRIVER_OBJECT DriverObject
)
{
PDEVICE_OBJECT deviceObject = DriverObject->DeviceObject;
UNICODE_STRING uniWin32NameString;
PAGED_CODE();
RtlInitUnicodeString(&uniWin32NameString, DOS_DEVICE_NAME);
IoDeleteSymbolicLink(&uniWin32NameString);
if (deviceObject != NULL) {
IoDeleteDevice(deviceObject);
}
return;
}
NTSTATUS
KasanTriggerDeviceControl(
PDEVICE_OBJECT DeviceObject,
PIRP Irp
)
{
PIO_STACK_LOCATION irpSp;
NTSTATUS ntStatus;
ULONG inBufLength;
ULONG inIndex;
ULONG outBufLength;
PUCHAR outValue;
PBOOLEAN isKasanEnabledOnDriver;
UNREFERENCED_PARAMETER(DeviceObject);
PAGED_CODE();
irpSp = IoGetCurrentIrpStackLocation(Irp);
inBufLength = irpSp->Parameters.DeviceIoControl.InputBufferLength;
outBufLength = irpSp->Parameters.DeviceIoControl.OutputBufferLength;
ntStatus = STATUS_SUCCESS;
switch (irpSp->Parameters.DeviceIoControl.IoControlCode)
{
case IOCTL_KASANTRIGGER_INFO:
//
// Return information. Just a BOOLEAN that indicates whether the
// driver was compiled with KASAN or not.
//
if (inBufLength != 0 || outBufLength != sizeof(BOOLEAN)) {
ntStatus = STATUS_INVALID_PARAMETER;
goto End;
}
isKasanEnabledOnDriver = (PBOOLEAN)Irp->AssociatedIrp.SystemBuffer;
#if defined(__SANITIZE_ADDRESS__)
*isKasanEnabledOnDriver = TRUE;
#else
*isKasanEnabledOnDriver = FALSE;
#endif
Irp->IoStatus.Information = sizeof(BOOLEAN);
break;
case IOCTL_KASANTRIGGER_OOBR_STACK:
//
// Trigger an out-of-bounds read on the stack.
//
if (inBufLength != sizeof(ULONG) || outBufLength != sizeof(UCHAR)) {
ntStatus = STATUS_INVALID_PARAMETER;
goto End;
}
inIndex = *((PULONG)Irp->AssociatedIrp.SystemBuffer);
outValue = (PUCHAR)Irp->AssociatedIrp.SystemBuffer;
*outValue = TriggerOobrStack(inIndex);
Irp->IoStatus.Information = sizeof(UCHAR);
break;
case IOCTL_KASANTRIGGER_OOBR_GLOBAL:
//
// Trigger an out-of-bounds read on a global variable.
//
if (inBufLength != sizeof(ULONG) || outBufLength != sizeof(UCHAR)) {
ntStatus = STATUS_INVALID_PARAMETER;
goto End;
}
inIndex = *((PULONG)Irp->AssociatedIrp.SystemBuffer);
outValue = (PUCHAR)Irp->AssociatedIrp.SystemBuffer;
*outValue = TriggerOobrGlobal(inIndex);
Irp->IoStatus.Information = sizeof(UCHAR);
break;
case IOCTL_KASANTRIGGER_OOBR_HEAP:
//
// Trigger an out-of-bounds read on a heap buffer.
//
if (inBufLength != sizeof(ULONG) || outBufLength != sizeof(UCHAR)) {
ntStatus = STATUS_INVALID_PARAMETER;
goto End;
}
inIndex = *((PULONG)Irp->AssociatedIrp.SystemBuffer);
outValue = (PUCHAR)Irp->AssociatedIrp.SystemBuffer;
*outValue = TriggerOobrHeap(inIndex);
Irp->IoStatus.Information = sizeof(UCHAR);
break;
default:
ntStatus = STATUS_INVALID_DEVICE_REQUEST;
break;
}
End:
Irp->IoStatus.Status = ntStatus;
IoCompleteRequest(Irp, IO_NO_INCREMENT);
return ntStatus;
}
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