ssh pubkeyauthentication problem

yangk — Thu, 27 May 2010 09:24:12 GMT

Hi All,

I have encountered a strange problem only with the non-root user to do the pubkey authentication.My machine is 11.23 PA machine.

file /opt/ssh/sbin/sshd
/opt/ssh/sbin/sshd: ELF-64 executable object file - PA-RISC 2.0 (LP64)

the sshd is 64 bit,and here is the debug message from the ssh client:
$ hostname
sshpa4

$ ssh sshpa4 -vvv
........
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug3: start over, passed a different list publickey,password,keyboard-interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/yangk/.ssh/identity
debug3: no such identity: /home/yangk/.ssh/identity
debug1: Offering public key: /home/yangk/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: fp ac:7a:a0:2a:7c:8b:a2:a3:5e:9d:f3:91:0f:ba:a6:17
debug3: sign_and_send_pubkey
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
debug1: Final hpn_buffer_size = 131072
debug1: HPN Disabled: 1, HPN Buffer Size: 131072
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
#0 client-session (t3 r-1 i0/0 o0/0 fd 6/7 cfd -1)

debug3: channel 0: close_fds r 6 w 7 e 8 c -1
Connection to sshpa4 closed by remote host.
Connection to sshpa4 closed.
Transferred: sent 2128, received 2072 bytes, in 0.0 seconds
Bytes per second: sent 70717.0, received 68856.1
debug1: Exit status -1

the publickey authentication is succeeded, but it is closed by the server.

But if I switch the 64 sshd to the 32 sshd, then it can work, that is so strange.
Here is the details:

root@sshpa4# file /opt/ssh/sbin/sshd
/opt/ssh/sbin/sshd: PA-RISC2.0 shared executable dynamically linked

$ ssh localhost -vvv
...............
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/yangk/.ssh/identity
debug3: no such identity: /home/yangk/.ssh/identity
debug1: Offering public key: /home/yangk/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: fp ac:7a:a0:2a:7c:8b:a2:a3:5e:9d:f3:91:0f:ba:a6:17
debug3: sign_and_send_pubkey
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
debug1: Final hpn_buffer_size = 131072
debug1: HPN Disabled: 1, HPN Buffer Size: 131072
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug2: callback start
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug2: channel 0: request shell confirm 1
debug2: fd 5 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 65536
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Last successful login: Thu May 27 18:16:40 EAT 2010 localhost
Last login: Thu May 27 18:07:43 2010 from sshpa5.chn.hp.com
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$ uname -a
HP-UX sshpa4 B.11.23 U 9000/800 3267743753 unlimited-user license

As you see,i can log into the localhost with publickey authentication.

So why the 64 bit sshd do not let the ssh login with publickey authentication ,but 32 bit sshd can allow?

This problem has so strange to me.
Could somebody give me help about this?
Thanks in advance!

Kevin

Re: ssh pubkeyauthentication problem

yangk — Thu, 27 May 2010 09:26:00 GMT

one thing to supplement the ssh client and the ssh server is the same machine which is sshpa4.

Re: ssh pubkeyauthentication problem

chenn_1 — Thu, 27 May 2010 09:42:29 GMT

Additionally, we've installed exactly the same SSH depot on another 11.23PA machine. And it works fine there. Seems that only "sshpa4" has this kind of issue. FYI.

Re: ssh pubkeyauthentication problem

mvpel — Thu, 27 May 2010 12:23:58 GMT

Your test cases aren't quite identical - in the first you ssh to sshpa4, in the second you ssh to localhost. I seem to recall that sshd can treat the loopback interface differently in some cases.

Try doing an "ssh localhost" with the 64-bit sshd just to be sure.

Re: ssh pubkeyauthentication problem

yangk — Fri, 28 May 2010 03:09:52 GMT

Hi mvpel,

the sshpa4 and localhost has the same issue.

Thanks!

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