Re: [Patch] fad-win32.c

[Gisle Vanem <gvanem () broadpark no>]

"Guy Harris" <guy () alum mit edu> wrote:

> > 'NameLength = 0' is just in case 'PacketGetAdapterNames()' fails
> > w/o setting '*NameLength == 0'. It really could do that; ref. Packet32.c in WinPcap.

> Really?  I don't see that.  (The first call should *always* "fail", in the sense of 
> returning FALSE; if the cause of the "failure" is that the buffer pointer argument 
> is NULL, not that it couldn't get the interface list, it should set NameLength 
> to the size of the buffer it needs.)

What is the oldest version of WinPcap we should support in
libpcap? Here are the lines in question from an old version of 
<winpcap-SDK>\Packet9x\DLL\Packet32.c:

BOOLEAN PacketGetAdapterNames (PTSTR pStr,
   PULONG BufferSize)
{
   ULONG  Result,i;
   LONG  Status;
...
 PPACKET_OID_DATA  OidData;
...

OidData=GlobalAllocPtr(GMEM_MOVEABLE | GMEM_ZEROINIT,256);
   if (OidData == NULL) 
{
       return FALSE;
   }

(dated 8 July 2006 here).

Clearly it could return FALSE w/o touching '*BufferSize'. The
GlobalAllocPtr() is the 1st code in this function. Hence the precaution 
in fad-win32.c. Allthough no sane person should be using Win9x anymore,
there could be an old version of PacketNtx\Dll\Packet32.c with the same
lines.

--gv

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