HP-UX 11 Corrupted MAC errors

Kevin Steves
Fri, 26 Jul 2002 16:23:19 -0000

On Fri, Jul 26, 2002 at 07:04:30AM -0400, Deron Meranda
wrote:
> Using 3.4p1 under HP-UX 11.0 I am repeatedly getting disconnected with
> Corrupted MAC on input.  I am connecting from a RedHat Linux client
> (at 3.1p1).
>
> The incorrect MAC is appearing on the server packet receive side.
> Never get an invalid MAC on the client side.  I'm currently diving
> into packet.c to try to find this, but the behavior is so strange and
> predictable I thought I'd see if anybody else has ever seen this.

i would look into the client side as well.  the sender could be
sending an invalid MAC.  can you dup with HP->HP?

> The strange thing is that the MAC error always occurs when starting an
> X application (emacs) using X forwarding, sometime between the X
> authentication check and when the window gets mapped (because it never
> appears).  I don't get corrupted MAC errors anyplace else.  I've
even
> forwarded other TCP ports through the ssh session and they cause no
> corrupt MACs either...only X sessions.  This happens with about 75%
> regularity..in those cases where it successfully gets the window
> mapped that channel never has problems no matter how long I use it.
> But each additional X forwarding channel I open has about a 75% chance
> of a corrupt MAC during or around the X authentication phase.

hmm, strange.

> Enabling or disabling compression has no effect.
> Choice of hmac-md5 or hmac-sha1 has no effect.
> Choice of cipher aes128-cbc or 3des-cbc has no effect.
>
> I have linked against several OpenSSL versions
>   0.9.6d - hp-parisc   (optimized for PA-RISC 1.1, no assembly)
>   0.9.6d - hp-parisc2  (optimized for PA-RISC 2.0 with assembly)
>   0.9.7beta2 - hp-parisc2

i use 0.9.6d with "hpux-parisc1_1-cc" with no problems on 11.11.

> All OpenSSL's pass their tests.  I'm also using these same OpenSSL
> libraries in Apache/mod_ssl and have not seen any errors there yet.
>
> Any obvious thoughts before I spend a lot of time tracing through the
> packet and crypto code?  The obvious first question to answer; is this
> OpenSSL or OpenSSH...I just don't know yet, but I suspect the later.