Leaked source code of windows server 2003
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197 lines
4.7 KiB

/*++
Copyright (c) 1990-1993 Microsoft Corporation
Module Name:
probe.c
Abstract:
This module implements the probe for write function.
Author:
David N. Cutler (davec) 19-Jan-1990
Environment:
Any mode.
Revision History:
--*/
#include "exp.h"
#if defined(_WIN64)
#include <wow64t.h>
#endif
#if defined(ALLOC_PRAGMA)
#pragma alloc_text(PAGE, ProbeForWrite)
#pragma alloc_text(PAGE, ProbeForRead)
#endif
VOID
ProbeForWrite (
IN PVOID Address,
IN SIZE_T Length,
IN ULONG Alignment
)
/*++
Routine Description:
This function probes a structure for write accessibility and ensures
correct alignment of the structure. If the structure is not accessible
or has incorrect alignment, then an exception is raised.
Arguments:
Address - Supplies a pointer to the structure to be probed.
Length - Supplies the length of the structure.
Alignment - Supplies the required alignment of the structure expressed
as the number of bytes in the primitive datatype (e.g., 1 for char,
2 for short, 4 for long, and 8 for quad).
Return Value:
None.
--*/
{
ULONG_PTR EndAddress;
ULONG_PTR StartAddress;
#if defined(_WIN64)
ULONG_PTR PageSize;
#else
#define PageSize PAGE_SIZE
#endif
//
// If the structure has zero length, then do not probe the structure for
// write accessibility or alignment.
//
if (Length != 0) {
//
// If the structure is not properly aligned, then raise a data
// misalignment exception.
//
ASSERT((Alignment == 1) || (Alignment == 2) ||
(Alignment == 4) || (Alignment == 8) ||
(Alignment == 16));
StartAddress = (ULONG_PTR)Address;
if ((StartAddress & (Alignment - 1)) == 0) {
//
// Compute the ending address of the structure and probe for
// write accessibility.
//
EndAddress = StartAddress + Length - 1;
if ((StartAddress <= EndAddress) &&
(EndAddress < MM_USER_PROBE_ADDRESS)) {
//
// N.B. Only the contents of the buffer may be probed.
// Therefore the starting byte is probed for the
// first page, and then the first byte in the page
// for each succeeding page.
//
#if defined(_WIN64)
//
// If this is a Wow64 process, then the native page is 4K, which
// could be smaller than the native page size/
//
if (PsGetCurrentProcess()->Wow64Process != NULL) {
PageSize = PAGE_SIZE_X86NT;
} else {
PageSize = PAGE_SIZE;
}
#endif
EndAddress = (EndAddress & ~(PageSize - 1)) + PageSize;
do {
*(volatile CHAR *)StartAddress = *(volatile CHAR *)StartAddress;
StartAddress = (StartAddress & ~(PageSize - 1)) + PageSize;
} while (StartAddress != EndAddress);
return;
} else {
ExRaiseAccessViolation();
}
} else {
ExRaiseDatatypeMisalignment();
}
}
return;
}
#undef ProbeForRead
NTKERNELAPI
VOID
NTAPI
ProbeForRead(
IN CONST VOID *Address,
IN SIZE_T Length,
IN ULONG Alignment
)
/*++
Routine Description:
This function probes a structure for read accessibility and ensures
correct alignment of the structure. If the structure is not accessible
or has incorrect alignment, then an exception is raised.
Arguments:
Address - Supplies a pointer to the structure to be probed.
Length - Supplies the length of the structure.
Alignment - Supplies the required alignment of the structure expressed
as the number of bytes in the primitive datatype (e.g., 1 for char,
2 for short, 4 for long, and 8 for quad).
Return Value:
None.
--*/
{
PAGED_CODE();
ASSERT(((Alignment) == 1) || ((Alignment) == 2) ||
((Alignment) == 4) || ((Alignment) == 8) ||
((Alignment) == 16));
if ((Length) != 0) {
if (((ULONG_PTR)(Address) & ((Alignment) - 1)) != 0) {
ExRaiseDatatypeMisalignment();
} else if ((((ULONG_PTR)(Address) + (Length)) < (ULONG_PTR)(Address)) ||
(((ULONG_PTR)(Address) + (Length)) > (ULONG_PTR)MM_USER_PROBE_ADDRESS)) {
ExRaiseAccessViolation();
}
}
}