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Fix several problems with lookasides and temporary captures:

Browse source 
ob_x.h: Add a proper define for the size of a lookaside name buffer
oblink.c: Use move memory rather than copy in the case that we re-use the name
  buffer.  We probably never reused it before, because MaximumLength was never
  set properly.  See below.
oblife.c: Several things
  ObpCaptureObjectName
  - Properly set MaximumLength rather than copping out and setting it to just
    string + nul.  This was dangerous because later, we'll use MaximumLength
    to determine whether we allocated the name from the lookaside list or the
    heap.
  - Since we use MaximumLength to determine where the allocation came from
    make sure that MaximumLength never equals the magic value if the string
    comes from the heap for whatever reason.
  - Free the string using the right symmetry if we would fault copying.
  ObpCaptureObjectCreateInformation
  - We didn't allocate the ObjectCreateInfo, but we might've allocated the
    security descriptor, so free it if needed, rather than borking some non
    heap.

svn path=/trunk/; revision=34783
This commit is contained in:
Art Yerkes 2008-07-25 13:42:05 +00:00
parent 4e945c2292
commit 6ae9a99375
3 changed files with 22 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
reactos/ntoskrnl/include/internal/ob_x.h
View file

@ -15,6 +15,8 @@
#define OBP_LOCK_STATE_RELEASED 0xEEEE1234
#define OBP_LOCK_STATE_INITIALIZED 0xFFFF1234
#define OBP_NAME_LOOKASIDE_MAX_SIZE 248
ULONG
FORCEINLINE
ObpSelectObjectLockSlot(IN POBJECT_HEADER ObjectHeader)

26
reactos/ntoskrnl/ob/oblife.c
View file

@ -300,9 +300,18 @@ ObpAllocateObjectNameBuffer(IN ULONG Length,
MaximumLength = Length + sizeof(UNICODE_NULL);
/* Check if we should use the lookaside buffer */
if (!(UseLookaside) || (MaximumLength > 248))
if (!(UseLookaside) || (MaximumLength > OBP_NAME_LOOKASIDE_MAX_SIZE))
{
/* Nope, allocate directly from pool */
/* Since we later use MaximumLength to detect that we're not allocating
* from a list, we need at least MaximumLength + sizeof(UNICODE_NULL)
* here.
*
* People do call this with UseLookasideList FALSE so the distinction
* is critical.
*/
if (MaximumLength <= OBP_NAME_LOOKASIDE_MAX_SIZE)
MaximumLength = OBP_NAME_LOOKASIDE_MAX_SIZE + sizeof(UNICODE_NULL);
Buffer = ExAllocatePoolWithTag(PagedPool,
MaximumLength,
OB_NAME_TAG);
@ -310,13 +319,13 @@ ObpAllocateObjectNameBuffer(IN ULONG Length,
else
{
/* Allocate from the lookaside */
//MaximumLength = 248; <= hack, we should actually set this...!
MaximumLength = OBP_NAME_LOOKASIDE_MAX_SIZE;
Buffer = ObpAllocateObjectCreateInfoBuffer(LookasideNameBufferList);
}
/* Setup the string */
ObjectName->Length = (USHORT)Length;
ObjectName->MaximumLength = (USHORT)MaximumLength;
ObjectName->Length = (USHORT)Length;
ObjectName->Buffer = Buffer;
return Buffer;
}
@ -328,7 +337,7 @@ ObpFreeObjectNameBuffer(IN PUNICODE_STRING Name)
PVOID Buffer = Name->Buffer;
/* We know this is a pool-allocation if the size doesn't match */
if (Name->MaximumLength != 248)
if (Name->MaximumLength != OBP_NAME_LOOKASIDE_MAX_SIZE)
{
/* Free it from the pool */
ExFreePool(Buffer);
@ -408,7 +417,7 @@ ObpCaptureObjectName(IN OUT PUNICODE_STRING CapturedName,
{
/* Handle exception and free the string buffer */
Status = _SEH_GetExceptionCode();
if (StringBuffer) ExFreePool(StringBuffer);
if (StringBuffer) ObpFreeObjectNameBuffer(CapturedName);
}
_SEH_END;
@ -477,7 +486,7 @@ ObpCaptureObjectCreateInformation(IN POBJECT_ATTRIBUTES ObjectAttributes,
if(!NT_SUCCESS(Status))
{
/* Capture failed, quit */
ObjectCreateInfo->SecurityDescriptor = NULL;
ObjectCreateInfo->SecurityDescriptor = NULL;
_SEH_LEAVE;
}
@ -541,7 +550,10 @@ ObpCaptureObjectCreateInformation(IN POBJECT_ATTRIBUTES ObjectAttributes,
}
/* Cleanup if we failed */
if (!NT_SUCCESS(Status)) ObpFreeObjectCreateInformation(ObjectCreateInfo);
if (!NT_SUCCESS(Status))
{
ObpReleaseObjectCreateInformation(ObjectCreateInfo);
}
/* Return status to caller */
return Status;

2
reactos/ntoskrnl/ob/oblink.c
View file

@ -181,7 +181,7 @@ ObpParseSymbolicLink(IN PVOID ParsedObject,
if (RemainingName->Length)
{
/* Copy the new path */
RtlCopyMemory((PVOID)((ULONG_PTR)NewTargetPath + TargetPath->Length),
RtlMoveMemory((PVOID)((ULONG_PTR)NewTargetPath + TargetPath->Length),
RemainingName->Buffer,
RemainingName->Length);
}