RE: RE: Clamd STREAM instability

> Tomasz Kojm
> Sent: Monday, August 22, 2005 10:49 AM
> To: ClamAV Development
> Subject: Re: [Clamav-devel] RE: Clamd STREAM instability
> 
> On Mon, 22 Aug 2005 08:10:10 -0400
> "Brian A. Reiter" <breiter@xxxxxxxxxxxxxxx> wrote:
> 
> > > Please try this fix:
> > > 
> > > Sun Aug 21 01:06:54 CEST 2005 (tk)
> > > ----------------------------------
> > >   * clamd: use reentrant version of gethostbyname when available
> > > 
> > 
> > Unfortunately, this patch was no more successful at 
> resolving the SEGV 
> > than my own efforts.
> 
> I was expecting the change won't help because the original 
> code was thread safe (the call to gethostbyname in the stream 
> scanner was protected with a mutex, and the call in 
> tcpserver() was not thread unsafe).
> 

I think I have this tracked down to a defect in the pthreads implementation
in libc on Interix 3.5. There is a hotfix available to fix pthreads by
replacing libc. The kb article doesn't mention sigsegv, but when I applied
it to my test environment clamd no longer segfaults with the TCPAddr option
set.

http://support.microsoft.com/kb/902074 [October 18, 2005]

"FIX: The computer may slow down and the application may stop responding
when you run a pthread-based application that uses the va_list variable on
Microsoft Windows Services for UNIX 3.5"

Unfortunatley, to get the hotfix, you have to contac Microsoft and request
it. That means opening a support ticket. Ultimately they do not charge for
the patch, but it is a lot of rigmarole.

Brian A. Reiter
WolfeReiter, LLC : Thoughtful Computing
[http://www.thoughtfulcomputing.com]

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