Multiple Platform remote CPU load issue in Samba 1.x and2.x

[Allen, Michael B (RSCH)]

Actually could this be a kernel networking issue with linux? I'm running
2.2.14-5.0. If not it should be trivial to fix. Anyone with a current CVS
checkout wanna come up with a quick patch?

Kudos to "The SecureXpert Team" for bringing this to our attention!

Michael B. Allen
http://jcifs.samba.org

> -----Original Message-----
> From:	J. Robert von Behren [SMTP:jrvb at cs.berkeley.edu]
> Sent:	Tuesday, June 13, 2000 8:38 PM
> To:	Michael_B_Allen at ml.com
> Cc:	Multiple recipients of list SAMBA-TECHNICAL
> Subject:	Re: Multiple Platform remote CPU load issue in Samba 1.x
> and2.x
> 
> 
> FWIW, I can reproduce this on my test machine (Redhat 6.0, kernel
> 2.2.5-15).  The following command does the trick:
> 
>      nc localhost 139 < /dev/zero
> 
> After watching smbd with gdb and strace, I found that the child smbd
> that was spawned in response to the nc connection just keeps reading
> zeros from the socket, and writing out error responses, ad infinitum.  A
> simple fix would be to abort the connection after a certain number of
> successive bad requests, or after a certain number of bad requests
> within a given time period.
> 
> Best regards,
> 
> -Rob von Behren
> 
> 
> 
> "Allen, Michael B (RSCH)" wrote:
> > 
> > > -----Original Message-----
> > > From: Allen, Michael B (RSCH)
> > >
> > >
> > > but smbd seems to drop the conn.
> >         [Allen, Michael B (RSCH)]
> > 
> >         Actually , I'm sorry this is not true. It appears to maintain
> the
> > connection and then close when the netcat program stops but there only a
> few
> > packets transpire on connection and then again on disconnect.
> > 
> >         PS:
> > 
> >         [root at prodlinux lib]# cat /dev/zero > /dev/null
> > 
> >         This runs the cpu up to 100% so I'm getting zeros
> > 
> >         [root at prodlinux lib]# cat /dev/zero | ./netcat localhost 139
> > 
> >         and this too does nothing.
> > 
> >         Michael B. Allen
> >         http://jcifs.samba.org