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[NTOSKRNL]

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- Improve the random address base code in MiCreatePebOrTeb to actually make sense and not rely on retarded hacks implicitly hardcoding the PEB size in pages into the random value generation.

svn path=/trunk/; revision=64591
This commit is contained in:
Timo Kreuzer 2014-10-08 00:31:35 +00:00
parent 4d4bb1e6cc
commit def3dc0080
1 changed files with 26 additions and 21 deletions
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47
reactos/ntoskrnl/mm/ARM3/procsup.c
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@ -48,13 +48,13 @@ NTSTATUS
NTAPI
MiCreatePebOrTeb(IN PEPROCESS Process,
IN ULONG Size,
OUT PULONG_PTR Base)
OUT PULONG_PTR BaseAddress)
{
PETHREAD Thread = PsGetCurrentThread();
PMMVAD_LONG Vad;
NTSTATUS Status;
ULONG RandomCoeff;
ULONG_PTR StartAddress, EndAddress;
ULONG_PTR HighestAddress, RandomBase;
ULONG AlignedSize;
LARGE_INTEGER CurrentTime;
TABLE_SEARCH_RESULT Result = TableFoundNode;
PMMADDRESS_NODE Parent;
@ -83,25 +83,30 @@ MiCreatePebOrTeb(IN PEPROCESS Process,
/* Check if this is a PEB creation */
if (Size == sizeof(PEB))
{
/* Start at the highest valid address */
StartAddress = (ULONG_PTR)MM_HIGHEST_VAD_ADDRESS + 1;
/* Select the random coefficient */
/* Create a random value to select one page in a 64k region */
KeQueryTickCount(&CurrentTime);
CurrentTime.LowPart &= ((64 * _1KB) >> PAGE_SHIFT) - 1;
if (CurrentTime.LowPart <= 1) CurrentTime.LowPart = 2;
RandomCoeff = CurrentTime.LowPart << PAGE_SHIFT;
CurrentTime.LowPart &= (_64K / PAGE_SIZE) - 1;
/* Select the highest valid address minus the random coefficient */
StartAddress -= RandomCoeff;
EndAddress = StartAddress + ROUND_TO_PAGES(Size) - 1;
/* Calculate a random base address */
RandomBase = (ULONG_PTR)MM_HIGHEST_VAD_ADDRESS + 1;
RandomBase -= CurrentTime.LowPart << PAGE_SHIFT;
/* Make sure the base address is not too high */
AlignedSize = ROUND_TO_PAGES(Size);
if ((RandomBase + AlignedSize) > (ULONG_PTR)MM_HIGHEST_VAD_ADDRESS + 1)
{
RandomBase = (ULONG_PTR)MM_HIGHEST_VAD_ADDRESS + 1 - AlignedSize;
}
/* Calculate the highest allowed address */
HighestAddress = RandomBase + AlignedSize - 1;
/* Try to find something below the random upper margin */
Result = MiFindEmptyAddressRangeDownTree(ROUND_TO_PAGES(Size),
EndAddress,
HighestAddress,
PAGE_SIZE,
&Process->VadRoot,
Base,
BaseAddress,
&Parent);
}
@ -113,7 +118,7 @@ MiCreatePebOrTeb(IN PEPROCESS Process,
(ULONG_PTR)MM_HIGHEST_VAD_ADDRESS,
PAGE_SIZE,
&Process->VadRoot,
Base,
BaseAddress,
&Parent);
/* Bail out, if still nothing free was found */
if (Result == TableFoundNode)
@ -125,12 +130,12 @@ MiCreatePebOrTeb(IN PEPROCESS Process,
}
/* Validate that it came from the VAD ranges */
ASSERT(*Base >= (ULONG_PTR)MI_LOWEST_VAD_ADDRESS);
ASSERT(*BaseAddress >= (ULONG_PTR)MI_LOWEST_VAD_ADDRESS);
/* Build the rest of the VAD now */
Vad->StartingVpn = (*Base) >> PAGE_SHIFT;
Vad->EndingVpn = ((*Base) + Size - 1) >> PAGE_SHIFT;
Vad->u3.Secured.StartVpn = *Base;
Vad->StartingVpn = (*BaseAddress) >> PAGE_SHIFT;
Vad->EndingVpn = ((*BaseAddress) + Size - 1) >> PAGE_SHIFT;
Vad->u3.Secured.StartVpn = *BaseAddress;
Vad->u3.Secured.EndVpn = (Vad->EndingVpn << PAGE_SHIFT) | (PAGE_SIZE - 1);
Vad->u1.Parent = NULL;
@ -146,7 +151,7 @@ MiCreatePebOrTeb(IN PEPROCESS Process,
Vad->ControlArea = NULL; // For Memory-Area hack
Vad->FirstPrototypePte = NULL;
DPRINT("VAD: %p\n", Vad);
DPRINT("Allocated PEB/TEB at: 0x%p for %16s\n", *Base, Process->ImageFileName);
DPRINT("Allocated PEB/TEB at: 0x%p for %16s\n", *BaseAddress, Process->ImageFileName);
MiInsertNode(&Process->VadRoot, (PVOID)Vad, Parent, Result);
/* Release the working set */