New subject: [ros-diffs] [tkreuzer] 64593: [NTOSKRNL] Modify MiCreatePebOrTeb to use MiInsertVadEx instead of doing everything "by hand". No, this does not "change Windows behavior". The TEB creation works exactly as befor...

11 Oct 2014

Why do you think PEB creation cannot fail in the first place?
Best regards,
Alex Ionescu
On Tue, Oct 7, 2014 at 5:31 PM, tkreuzer@svn.reactos.org wrote:
...
Author: tkreuzer
Date: Wed Oct  8 00:31:49 2014
New Revision: 64593
URL: http://svn.reactos.org/svn/reactos?rev=64593&view=rev
Log:
[NTOSKRNL]
Modify MiCreatePebOrTeb to use MiInsertVadEx instead of doing everything
"by hand". No, this does not "change Windows behavior". The TEB creation
works exactly as before, and the only difference in the PEB creation is
that if the first attempt fails, we will no longer try again from the top
of the address space. But since this cannot fail in the first place, at
least not due to the VA range not being free, another attempt would be
pointless anyway!
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?...
==============================================================================

--- trunk/reactos/ntoskrnl/mm/ARM3/procsup.c    [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/procsup.c    [iso-8859-1] Wed Oct  8
00:31:49 2014
@@ -50,14 +50,11 @@
                  IN ULONG Size,
                  OUT PULONG_PTR BaseAddress)
 {

PETHREAD Thread = PsGetCurrentThread();
PMMVAD_LONG Vad;
NTSTATUS Status;
ULONG_PTR HighestAddress, RandomBase;
ULONG AlignedSize;
LARGE_INTEGER CurrentTime;

TABLE_SEARCH_RESULT Result = TableFoundNode;

PMMADDRESS_NODE Parent;
/* Allocate a VAD */
Vad = ExAllocatePoolWithTag(NonPagedPool, sizeof(MMVAD_LONG), 'ldaV');


@@ -70,6 +67,7 @@
     Vad->u.VadFlags.PrivateMemory = TRUE;
     Vad->u.VadFlags.Protection = MM_READWRITE;
     Vad->u.VadFlags.NoChange = TRUE;

Vad->u1.Parent = NULL;
/* Setup the secondary flags to make it a secured, writable, long VAD


*/
     Vad->u2.LongFlags2 = 0;
@@ -77,10 +75,11 @@
     Vad->u2.VadFlags2.LongVad = TRUE;
     Vad->u2.VadFlags2.ReadOnly = FALSE;

/* Lock the process address space */
KeAcquireGuardedMutex(&Process->AddressCreationLock);


Vad->ControlArea = NULL; // For Memory-Area hack

Vad->FirstPrototypePte = NULL;
/* Check if this is a PEB creation */

ASSERT(sizeof(TEB) != sizeof(PEB));
if (Size == sizeof(PEB))
{
    /* Create a random value to select one page in a 64k region */


@@ -100,68 +99,27 @@
     /* Calculate the highest allowed address */
     HighestAddress = RandomBase + AlignedSize - 1;



   /* Try to find something below the random upper margin */


   Result = MiFindEmptyAddressRangeDownTree(ROUND_TO_PAGES(Size),


                                            HighestAddress,


                                            PAGE_SIZE,


                                            &Process->VadRoot,


                                            BaseAddress,


                                            &Parent);


}

/* Check for success. TableFoundNode means nothing free. */
if (Result == TableFoundNode)
{
   /* For TEBs, or if a PEB location couldn't be found, scan the VAD



root */

   Result = MiFindEmptyAddressRangeDownTree(ROUND_TO_PAGES(Size),




(ULONG_PTR)MM_HIGHEST_VAD_ADDRESS,

                                            PAGE_SIZE,


                                            &Process->VadRoot,


                                            BaseAddress,


                                            &Parent);


   /* Bail out, if still nothing free was found */


   if (Result == TableFoundNode)


   {


       KeReleaseGuardedMutex(&Process->AddressCreationLock);


       ExFreePoolWithTag(Vad, 'ldaV');


       return STATUS_NO_MEMORY;


   }


}

/* Validate that it came from the VAD ranges */
ASSERT(*BaseAddress >= (ULONG_PTR)MI_LOWEST_VAD_ADDRESS);

/* Build the rest of the VAD now */
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;

/* FIXME: Should setup VAD bitmap */
Status = STATUS_SUCCESS;

/* Pretend as if we own the working set */
MiLockProcessWorkingSetUnsafe(Process, Thread);

/* Insert the VAD */
ASSERT(Vad->EndingVpn >= Vad->StartingVpn);
Process->VadRoot.NodeHint = Vad;
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", *BaseAddress,

Process->ImageFileName);

MiInsertNode(&Process->VadRoot, (PVOID)Vad, Parent, Result);

/* Release the working set */
MiUnlockProcessWorkingSetUnsafe(Process, Thread);

/* Release the address space lock */
KeReleaseGuardedMutex(&Process->AddressCreationLock);

/* Return the status */
return Status;


}
else
{
   HighestAddress = (ULONG_PTR)MM_HIGHEST_VAD_ADDRESS;


}

*BaseAddress = 0;
Status = MiInsertVadEx((PMMVAD)Vad,
                      BaseAddress,


                      BYTES_TO_PAGES(Size),


                      HighestAddress,


                      PAGE_SIZE,


                      MEM_TOP_DOWN);


if (!NT_SUCCESS(Status))
{
   ExFreePoolWithTag(Vad, 'ldaV');


   return STATUS_NO_MEMORY;


}

/* Success */
return STATUS_SUCCESS;

}
VOID

    

Re: [ros-dev] [ros-diffs] [tkreuzer] 64593: [NTOSKRNL] Modify MiCreatePebOrTeb to use MiInsertVadEx instead of doing everything "by hand". No, this does not "change Windows behavior". The TEB creation works exactly as befor...