Source code of Windows XP (NT5)
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
vfstack.c
Abstract:
This module contains code required to verify drivers don't improperly use
thread stacks.
Author:
Adrian J. Oney (adriao) 09-May-1998
Environment:
Kernel mode.
--*/
#include "vfdef.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGEVRFY, VfStackSeedStack)
#endif
VOID
FASTCALL
VfStackSeedStack(
IN ULONG Seed
)
/*++
Description:
This routine "seeds" the stack so that uninitialized variables are
more easily ferreted out.
Note if the thread subsequently does a usermode wait, the memory
manager throws out the filled pages on stack swapout and on swapin
replaces them with randomly filled ones.
Arguments:
Seed - Value to seed stack with.
Return Value:
None.
--*/
{
#if !defined(_WIN64)
KIRQL oldIrql;
PKTHREAD Thread;
PULONG StartingAddress;
PULONG StackPointer;
if (!VfSettingsIsOptionEnabled(NULL, VERIFIER_OPTION_SEEDSTACK)) {
return;
}
Thread = KeGetCurrentThread ();
StartingAddress = (PULONG) Thread->StackLimit;
//
// We are going below the stack pointer. Make sure no interrupt can occur.
//
KeRaiseIrql (HIGH_LEVEL, &oldIrql);
_asm {
mov StackPointer, esp
}
//
// Check the stack bounds and don't fill if some caller is whacking the
// stack pointer.
//
if ((StackPointer <= StartingAddress) || (StackPointer >= (PULONG)Thread->StackBase)) {
KeLowerIrql (oldIrql);
return;
}
//
// We use the return value 0xFFFFFFFF, as it is an illegal return value. We
// are trying to catch people who don't initialize NTSTATUS, and it's also
// a good pointer trap too.
//
// Note RtlFillMemoryUlong is not used because calling it would use
// additional stack which we don't want to have to account for in our
// calculations.
//
while (StartingAddress < StackPointer) {
*StartingAddress = Seed;
StartingAddress += 1;
}
KeLowerIrql (oldIrql);
#else
UNREFERENCED_PARAMETER (Seed);
#endif
}