Login hangs in X11 with AIX 5.2 - SSH

This is a discussion on Login hangs in X11 with AIX 5.2 - SSH ; I have an AIX 5.3 server running openSSH 4.1p1 from IBM's "OpenSSH on AIX" sourceforge site ( http://sourceforge.net/projects/openssh-aix ) and a downloaded OpenSSL 0.9.7g RPM package. It ran fine until I recently applied maintenance, bringing the box to 5.3.03 from ...

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Thread: Login hangs in X11 with AIX 5.2

  1. Login hangs in X11 with AIX 5.2

    I have an AIX 5.3 server running openSSH 4.1p1 from IBM's "OpenSSH on
    AIX" sourceforge site (http://sourceforge.net/projects/openssh-aix) and
    a downloaded OpenSSL 0.9.7g RPM package. It ran fine until I recently
    applied maintenance, bringing the box to 5.3.03 from 5.3.01. Now SSH
    hangs during login, apparently during X11 authentication. (I see
    "/usr/bin/X11/xauth -q -" in the process list.) I do not normally use
    X, but we leave it enabled for users. If I unset the DISPLAY variable
    before issuing the ssh command, the login proceeds normally - no
    problems.

    When I login with a remote shell, whether from another AIX box or via
    Putty from my desktop, the session usually just hangs and never
    recovers - no error messages or anything. Occasionaly it only hangs
    for about 30 seconds before giving me the following error, and then I
    finally get logged in:
    /usr/bin/X11/xauth: 1356-361 Timeout in locking authority file
    /home/sbassle/.Xauthority.

    When I run remote commands or scripts, the session always hangs and
    never recovers. If I press ctrl-c I get kicked out. If I'm logged in
    with another session and kill the xauth process, the login continues
    and the command runs successfully. BTW, before I do this, I can see
    files .Xauthority-c and .Xauthority-l in my home directory, both with 0
    bytes.

    Here's some verbose output from: "ssh -vvv ls -l":
    ....
    debug3: authmethod_is_enabled publickey
    debug1: Next authentication method: publickey
    debug1: Offering public key: /home/sbassle/.ssh/id_rsa
    debug3: send_pubkey_test
    debug2: we sent a publickey packet, wait for reply
    debug1: Server accepts key: pkalg ssh-rsa blen 149
    debug2: input_userauth_pk_ok: fp
    71:0d:30:3b:af:92:ab:a6:35:a5:5c:24:66:19:9a:e6
    debug3: sign_and_send_pubkey
    debug1: Authentication succeeded (publickey).
    debug1: channel 0: new [client-session]
    debug3: ssh_session2_open: channel_new: 0
    debug2: channel 0: send open
    debug1: Entering interactive session.
    debug2: callback start
    debug2: ssh_session2_setup: id 0
    debug2: x11_get_proto: /usr/bin/X11/xauth -f
    /tmp/ssh-FjJVe44028/xauthfile generate unix:10.0 MIT-MAGIC-COOKIE-1
    untrusted timeout 1200 2>/dev/null
    debug2: x11_get_proto: /usr/bin/X11/xauth list unix:10.0 . 2>/dev/null
    debug1: Requesting X11 forwarding with authentication spoofing.
    debug2: channel 0: request x11-req
    debug1: Requesting authentication agent forwarding.
    debug2: channel 0: request auth-agent-req@openssh.com
    debug1: Sending command: ls -l
    debug2: channel 0: request exec
    debug2: fd 3 setting TCP_NODELAY
    debug2: callback done
    debug2: channel 0: open confirm rwindow 0 rmax 32768
    debug2: channel 0: rcvd adjust 131072

    At this point, the login hangs forever, or at least longer than 20
    minutes, at which time I pressed ctrl-c and received the following:

    debug1: channel 0: free: client-session, nchannels 1
    debug3: channel 0: status: The following connections are open:
    #0 client-session (t4 r0 i0/0 o0/0 fd 4/5)
    debug3: channel 0: close_fds r 4 w 5 e 6
    Killed by signal 2.

    Running the same command to connect to an AIX 5.2 box running
    openSSH_3.8.1.p1 produces exactly the same results up to the point of
    the hang, then continues with:

    debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
    debug2: channel 0: rcvd eof
    debug2: channel 0: output open -> drain
    debug2: channel 0: rcvd close
    debug2: channel 0: close_read
    debug2: channel 0: input open -> closed
    debug3: channel 0: will not send data after close
    -- "ls -l" command output here...
    debug3: channel 0: will not send data after close
    debug2: channel 0: obuf empty
    debug2: channel 0: close_write
    debug2: channel 0: output drain -> closed
    debug2: channel 0: almost dead
    debug2: channel 0: gc: notify user
    debug2: channel 0: gc: user detached
    debug2: channel 0: send close
    debug2: channel 0: is dead
    debug2: channel 0: garbage collecting
    debug1: channel 0: free: client-session, nchannels 1
    debug3: channel 0: status: The following connections are open:
    #0 client-session (t4 r0 i3/0 o3/0 fd -1/-1)
    debug3: channel 0: close_fds r -1 w -1 e 6
    debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 6.3 seconds
    debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
    debug1: Exit status 0

    In sshd_config, I have the following options turned on:
    Protocol 2
    PermitRootLogin no
    X11Forwarding yes
    Compression no

    In ssh_config, I have the following options turned on:
    ForwardAgent yes
    ForwardX11 yes
    Protocol 2

    I don't believe I can roll this out to users until I get this resolved,
    so I would really appreciate any help. Thanks!
    Steve


  2. Re: Login hangs in X11 with AIX 5.2

    On Wed, 16 Nov 2005 05:48:01 -0800, Steve wrote:

    > I have an AIX 5.3 server running openSSH 4.1p1 from IBM's "OpenSSH on AIX"
    > sourceforge site (http://sourceforge.net/projects/openssh-aix) and a
    > downloaded OpenSSL 0.9.7g RPM package. It ran fine until I recently
    > applied maintenance, bringing the box to 5.3.03 from 5.3.01. Now SSH
    > hangs during login, apparently during X11 authentication. (I see
    > "/usr/bin/X11/xauth -q -" in the process list.) I do not normally use X,
    > but we leave it enabled for users. If I unset the DISPLAY variable before
    > issuing the ssh command, the login proceeds normally - no problems.
    >
    > When I login with a remote shell, whether from another AIX box or via
    > Putty from my desktop, the session usually just hangs and never recovers -
    > no error messages or anything. Occasionaly it only hangs for about 30
    > seconds before giving me the following error, and then I finally get
    > logged in:
    > /usr/bin/X11/xauth: 1356-361 Timeout in locking authority file
    > /home/sbassle/.Xauthority.


    This is a known bug in ML03 - see APAR IY76807.



    > I don't believe I can roll this out to users until I get this resolved, so
    > I would really appreciate any help. Thanks! Steve


    --
    George Baltz N3GB
    Computer Sciences Corp Rule of thumb: ANYthing offered
    @NOAA/NESDIS/IPD by unsolicited email is a hoax,
    Suitland, MD 20746 ripoff, scam or outright fraud.


  3. Re: Login hangs in X11 with AIX 5.2

    Wonderful! Exactly what I was looking for.

    Thanks!
    Steve


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