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[RTL]

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- Implement dynamic allocation of handle entry pages in RtlAllocateHandle
- Fix a possible NULL pointer dereference

svn path=/trunk/; revision=57942
This commit is contained in:
Timo Kreuzer 2012-12-18 10:10:34 +00:00
parent 2cdf5f5ce0
commit be5ff02f5e
1 changed files with 51 additions and 28 deletions
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79
reactos/lib/rtl/handle.c
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@ -60,66 +60,89 @@ RtlAllocateHandle(
PRTL_HANDLE_TABLE HandleTable,
PULONG Index)
{
PRTL_HANDLE_TABLE_ENTRY *pp_new, *pph, ph;
PRTL_HANDLE_TABLE_ENTRY CurrentEntry, NextEntry;
NTSTATUS Status;
PRTL_HANDLE_TABLE_ENTRY retval;
PRTL_HANDLE_TABLE_ENTRY HandleEntry;
PVOID ArrayPointer;
SIZE_T ArraySize;
ULONG i, NumberOfEntries;
pp_new = &HandleTable->FreeHandles;
/* Check if we are out of free handles entries */
if (HandleTable->FreeHandles == NULL)
{
/* no free handle available */
/* Check if we don't have uncomitted handle entries yet */
if (HandleTable->UnCommittedHandles == NULL)
{
/* allocate handle array */
/* Use the maximum number of handle entries */
ArraySize = HandleTable->SizeOfHandleTableEntry * HandleTable->MaximumNumberOfHandles;
ArrayPointer = NULL;
/* FIXME - only reserve handles here! */
Status = NtAllocateVirtualMemory(NtCurrentProcess(),
(PVOID*)&ArrayPointer,
/* Reserve memory */
Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
&ArrayPointer,
0,
&ArraySize,
MEM_RESERVE | MEM_COMMIT,
MEM_RESERVE,
PAGE_READWRITE);
if (!NT_SUCCESS(Status))
return NULL;
/* update handle array pointers */
HandleTable->FreeHandles = (PRTL_HANDLE_TABLE_ENTRY)ArrayPointer;
HandleTable->MaxReservedHandles = (PRTL_HANDLE_TABLE_ENTRY)((ULONG_PTR)ArrayPointer + ArraySize);
HandleTable->CommittedHandles = (PRTL_HANDLE_TABLE_ENTRY)ArrayPointer;
/* Update handle array pointers */
HandleTable->UnCommittedHandles = (PRTL_HANDLE_TABLE_ENTRY)ArrayPointer;
HandleTable->MaxReservedHandles = (PRTL_HANDLE_TABLE_ENTRY)((ULONG_PTR)ArrayPointer + ArraySize);
}
/* FIXME - should check if handles need to be committed */
/* Commit one reserved handle entry page */
ArraySize = PAGE_SIZE;
ArrayPointer = HandleTable->UnCommittedHandles;
Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
&ArrayPointer,
0,
&ArraySize,
MEM_COMMIT,
PAGE_READWRITE);
if (!NT_SUCCESS(Status))
return NULL;
/* build free list in handle array */
ph = HandleTable->FreeHandles;
pph = pp_new;
while (ph < HandleTable->MaxReservedHandles)
/* Update handle array pointers */
HandleTable->FreeHandles = (PRTL_HANDLE_TABLE_ENTRY)ArrayPointer;
HandleTable->CommittedHandles = (PRTL_HANDLE_TABLE_ENTRY)ArrayPointer;
HandleTable->UnCommittedHandles = (PRTL_HANDLE_TABLE_ENTRY)((ULONG_PTR)ArrayPointer + ArraySize);
/* Calculate the number of entries we can store in the array */
NumberOfEntries = ArraySize / HandleTable->SizeOfHandleTableEntry;
/* Loop all entries, except the last one */
CurrentEntry = HandleTable->FreeHandles;
for (i = 0; i < NumberOfEntries - 1; i++)
{
*pph = ph;
pph = &ph->NextFree;
ph = (PRTL_HANDLE_TABLE_ENTRY)((ULONG_PTR)ph + HandleTable->SizeOfHandleTableEntry);
/* Calculate the address of the next handle entry */
NextEntry = (PRTL_HANDLE_TABLE_ENTRY)((ULONG_PTR)CurrentEntry +
HandleTable->SizeOfHandleTableEntry);
/* Link the next entry */
CurrentEntry->NextFree = NextEntry;
/* Continue with the next entry */
CurrentEntry = NextEntry;
}
*pph = 0;
/* CurrentEntry now points to the last entry, terminate the list here */
CurrentEntry->NextFree = NULL;
}
/* remove handle from free list */
retval = *pp_new;
*pp_new = retval->NextFree;
retval->NextFree = NULL;
HandleEntry = HandleTable->FreeHandles;
HandleTable->FreeHandles = HandleEntry->NextFree;
HandleEntry->NextFree = NULL;
if (Index)
{
*Index = ((ULONG)((ULONG_PTR)retval - (ULONG_PTR)HandleTable->CommittedHandles) /
*Index = ((ULONG)((ULONG_PTR)HandleEntry - (ULONG_PTR)HandleTable->CommittedHandles) /
HandleTable->SizeOfHandleTableEntry);
}
return retval;
return HandleEntry;
}