Packet integrity error. (34)

[Richard E. Silverman]

markus> it seems that SecureCRT sends a display 'screen' number in the x11
markus> request packet, but did not set the matching protocol flag in an
markus> earlier message. this worked before because OpenSSH-2.3.0p1 was buggy
markus> and ignored the protocol flag....

I actually also noticed this also a day or so ago, and was about to post about
it here when I checked and saw this thread.

This is a problem with the F-Secure client as well as SecureCRT.  Both
programs do not set the SSH_PROTOFLAG_SCREEN_NUMBER protocol flag in SSH-1
sessions, even though they do in fact include the X11 screen number field in
SSH_CMSG_X11_REQUEST_FORWARDING packets.  This was not a problem -- until
Markus added code to session.c in 2.5 to check actual vs expected packet
lengths on these requests.  Now, SSH-1 connections with X forwarding from
these clients fail immediately with the message, "packet integrity error."
I've submitted bug reports to both companies.

A small note: I think it would be good to change the error message -- "packet
integrity error" sounds like the crc-32 integrity check failed, which isn't
what happened.  Perhaps instead, "expected packet length did not match
actual."

- Richard