Where't the unit test proving your 'improved' algorithm matches XP SP2/SRV03 SP1?
Best regards, Alex Ionescu On Tue, Oct 7, 2014 at 5:31 PM, <tkreu...@svn.reactos.org> wrote: > Author: tkreuzer > Date: Wed Oct 8 00:31:35 2014 > New Revision: 64591 > > URL: http://svn.reactos.org/svn/reactos?rev=64591&view=rev > Log: > [NTOSKRNL] > - 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. > > Modified: > trunk/reactos/ntoskrnl/mm/ARM3/procsup.c > > Modified: trunk/reactos/ntoskrnl/mm/ARM3/procsup.c > URL: > http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/procsup.c?rev=64591&r1=64590&r2=64591&view=diff > > ============================================================================== > --- trunk/reactos/ntoskrnl/mm/ARM3/procsup.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/mm/ARM3/procsup.c [iso-8859-1] Wed Oct 8 > 00:31:35 2014 > @@ -48,13 +48,13 @@ > 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 @@ > /* 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; > - > - /* Select the highest valid address minus the random coefficient > */ > - StartAddress -= RandomCoeff; > - EndAddress = StartAddress + ROUND_TO_PAGES(Size) - 1; > + CurrentTime.LowPart &= (_64K / PAGE_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 @@ > > (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 @@ > } > > /* 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 @@ > 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 */ > > >
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