security/clamav: Segmentation fault when running clamav in a 32-bit jail on a 64-bit host

Jeremy Chadwick freebsd at
Fri Aug 27 17:32:13 UTC 2010

On Fri, Aug 27, 2010 at 01:06:49PM -0400, Glen Barber wrote:
> On 8/27/10 12:54 PM, Jeremy Chadwick wrote:
> > On Fri, Aug 27, 2010 at 12:46:48PM -0400, Glen Barber wrote:
> >> On 8/27/10 12:33 PM, Kurt Jaeger wrote:
> >>> Hi!
> >>>
> >>>> I have a few clamav instances running in jails on 32-bit hosts without
> >>>> any issues.  A few days ago one of these jails was migrated to a 64-bit
> >>>> host (8.1-RELEASE), where I noticed clamd (0.96.2_1) segfaults when queried.
> >>>>
> >>>> The issue seems specific to 32bit/64bit compatibility.  I have a gdb
> >>>> session available here:
> >>>>
> >>>> Any thoughts on if this is possible?
> >>>
> >>> Try
> >>>
> >>> Bytecode no
> >>>
> >>> in clamd.conf ?
> >>>
> >>
> >> It was set to 'yes' initially.  I thought it was disabled with building
> >> without JIT.  At any rate, no, it still segfaults with the same backtrace.
> > 
> > 1) Is clamd built with debugging symbols enabled?  If not, you might want
> > to rebuild it with such, else it might be difficult to debug the
> > problem.
> > 
> It wasn't initially, but is now.
> > Also, if the segfault happens after performing the above, can you
> > provide output from "bt full" instead of just "bt"?
> > 
> Of course.  The new backtrace is here:

I want to make sure I understand the environment -- on a native i386
(32-bit) FreeBSD host, the software works fine.  But on a native amd64
(64-bit) FreeBSD host, the software segfaults.  Correct?

If so -- it appears as if the system you're providing the backtrace from
is a 32-bit system, or within a 32-bit environment?  I would expect to
see 64-bit addresses in the backtrace, yet they're all 32-bit.

I'm not familiar with jailed environments (or the concept/possibility of
running a mixed-architecture jail (e.g. 64-bit host OS with 32-bit
jails)).  I don't use lib32 on my amd64 systems.

I did take a look at the clamav code itself (I'd have to spend a few
hundred lines outlining it here and would rather not).  My guess is that
there's a conflict between what the running OS architecture is and what
the build process determines the architecture is.

Given that you have jails, and possibly a mixed architecture environment
on a single host (e.g. 64-bit host OS with 32-bit jails), can you
explain exactly how you go about building clamav, followed by how you go
about running it?


| Jeremy Chadwick                                   jdc at |
| Parodius Networking              |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

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