[gentoo-user] Problems setting up sshd on an installation kernel

[Alan Mackenzie <acm@muc.de>]

Hi, folks!

I'm trying to get sshd working on an embryonic Gentoo installation on my
laptop.  The reason is that I want to ssh from my nice comfy desktop
system into this laptop to do the rest of the installation stuff.

The installation kernel with which I'm having problems is:
Linux livecd 2.6.30-gentoo-r8 #1 SMP Tue Nov 3 11:40:51 UTC 2009.

Having started sshd on my laptop, when I do

    ssh -lroot 192.168.2.101

from my desktop, I get prompted for my ssh key's pass phrase, which I
enter.  Thereafter, nothing happens, and it continues to happen for a
long, long time.

I've run sshd as sshd -d, which puts debugging info onto the screen.  It
turns out my system can't create a pty "pseudo terminal".  Here is the
debugging output.  Please note the lines marked by "<=====":

Postponed publickey for root from 192.168.2.100 port 41130 ssh2
debug1: userauth-request for user root service ssh-connection method
publickey
debug1: attempt 2 failures 0
debug1: temporarily_use_uid: 0/0 (e=0/0)
debug1: trying public key file /root/.ssh/authorized_keys
debug1: fd 4 clearing O_NONBLOCK
debug1: matching key found: file /root/.ssh/authorized_keys, line 1
Found matching DSA key: a8:6a:76:30:f8:a4:4e:c4:3b:cd:ba:3d:20:87:0c:8f
debug1: restore_uid: 0/0
debug1: ssh_dss_verify: signature correct
debug1: do_pam_account: called
Accepted publickey for root from 192.168.2.100 port 41130 ssh2
debug1: monitor_child_preauth: root has been authenticated by privileged
process
debug1: PAM: establishing credentials
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 65536 max
16384
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: session 0
debug1: session_open: channel 0
debug1: session_open: session 0: link with channel 0
debug1: server_input_channel_open: confirm session
debug1: server_input_channel_req: channel 0 request pty-req reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req pty-req
debug1: Allocating pty.                        <==========================
openpty: No such file or dIrectory             <==========================
session_pty_req: session 0 alloc failed        <==========================
debug1: server_input_channel_req: channel 0 request shell reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req shell
debug1: Forced command (key option) '/bin/bash'
Exiting on signal 2
debug1: do_cleanup
debug1: PAM: cleanup
debug1: PAM: deleting credentials
debug1: PAM: closing session

Clearly openpty (a C function) is failing to find some file.  Don't you
just love error messages like "No such file or directory" which forget
to identify the filename?  I'm guessing that the file it can't find is
the device file for the new pty.

Is there anything I can do to get sshd working from this kernel (and if
so, what?), or is there something fundamentally wrong with the kernel
configuration?

Thanks in advance for any and all help!

-- 
Alan Mackenzie (Nuremberg, Germany).