topic Re: SSH Host based Authentication setup in Operating System - Linux

SSH Host based Authentication setup

Michael Selvesteen_2 — Thu, 19 May 2005 05:39:02 GMT

Folks,

I am trying to set up Host based authentication between two linux boxes (i686-pc-linux-gnu).

I have done the following,

1. Copied the client's hostkey to (/usr/local/etc/ssh_host_rsa_key) the server's
/usr/local/etc/ssh_known_hosts.

2. Added the client's domain name and username to /.shosts

3. Also to the /etc/hosts.equiv.

The Server and client configurations are correct. ( enabled hostbased authentication related directives in server and Enabled keysign directive in client)

But still I could not succeed with Hostbased authentication.

ssh -l root -o'preferredauthentications=hostbased' -p 2222 ibm

The authenticity of host 'ibm (172.16.1.196)' can't be established.
RSA key fingerprint is 1f:97:24:d3:0a:b2:74:9d:ff:8f:2f:32:b3:ff:01:94.
Are you sure you want to continue connecting (yes/no)? yes

Warning: Permanently added 'ibm,172.16.1.196' (RSA) to the list of known hosts.
Permission denied (publickey,password,hostbased).
--

Do I miss anything.. Please help.

Re: SSH Host based Authentication setup

Gopi Sekar — Thu, 19 May 2005 06:31:11 GMT

can you attach the output with ssh -vvv

it will give some more insight and easy to diagnoise. also check /var/log/messages and /var/log/secure in the server to find out any thing wrong

Hope this helps,
Gopi

Re: SSH Host based Authentication setup

Rick Garland — Thu, 19 May 2005 09:12:25 GMT

Permission denied.

Check the perms on the $HOME/.ssh/known_hosts file.

Re: SSH Host based Authentication setup

Michael Selvesteen_2 — Thu, 19 May 2005 09:39:04 GMT

Hello All,

Here is the Client Log

ssh -l root -p 2222 -o'preferredauthentications=hostbased' ibm -vvv
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
debug1: Reading configuration data /usr/local/etc/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to ibm [172.16.1.196] port 2222.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_3.9p1
debug1: match: OpenSSH_3.9p1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.9p1
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 134/256
debug2: bits set: 520/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug3: check_host_in_hostfile: filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug1: Host 'ibm' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:2
debug2: bits set: 499/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /root/.ssh/identity ((nil))
debug2: key: /root/.ssh/id_rsa ((nil))
debug2: key: /root/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password,hostbased
debug3: start over, passed a different list publickey,password,hostbased
debug3: preferred hostbased
debug3: authmethod_lookup hostbased
debug3: remaining preferred:
debug1: No more authentication methods to try.
Permission denied (publickey,password,hostbased).

Re: SSH Host based Authentication setup

Michael Selvesteen_2 — Thu, 19 May 2005 09:40:48 GMT

Following is the Server debug messages

debug3: RNG is ready, skipping seeding
debug2: load_server_config: filename /usr/local/etc/sshd_config
debug2: load_server_config: done config len = 253
debug2: parse_server_config: config /usr/local/etc/sshd_config len 253
debug1: sshd version OpenSSH_4.1p1
debug1: private host key: #0 type 0 RSA1
debug3: Not a RSA1 key file /usr/local/etc/ssh_host_rsa_key.
debug1: read PEM private key done: type RSA
debug1: private host key: #1 type 1 RSA
debug3: Not a RSA1 key file /usr/local/etc/ssh_host_dsa_key.
debug1: read PEM private key done: type DSA
debug1: private host key: #2 type 2 DSA
debug1: rexec_argv[0]='/root/openssh-SNAP-20050517/sshd'
debug1: rexec_argv[1]='-ddde'
debug1: rexec_argv[2]='-p'
debug1: rexec_argv[3]='2222'
debug2: fd 3 setting O_NONBLOCK
debug1: Bind to port 2222 on ::.
Server listening on :: port 2222.
debug2: fd 4 setting O_NONBLOCK
debug1: Bind to port 2222 on 0.0.0.0.
Bind to port 2222 on 0.0.0.0 failed: Address already in use.
Generating 768 bit RSA key.
RSA key generation complete.
debug3: fd 4 is not O_NONBLOCK
debug1: Server will not fork when running in debugging mode.
debug3: send_rexec_state: entering fd = 7 config len 253
debug3: ssh_msg_send: type 0
debug3: send_rexec_state: done
debug1: rexec start in 4 out 4 newsock 4 pipe -1 sock 7
debug3: RNG is ready, skipping seeding
debug3: recv_rexec_state: entering fd = 5
debug3: ssh_msg_recv entering
debug3: recv_rexec_state: done
debug2: parse_server_config: config rexec len 253
debug1: sshd version OpenSSH_4.1p1
debug1: private host key: #0 type 0 RSA1
debug3: Not a RSA1 key file /usr/local/etc/ssh_host_rsa_key.
debug1: read PEM private key done: type RSA
debug1: private host key: #1 type 1 RSA
debug3: Not a RSA1 key file /usr/local/etc/ssh_host_dsa_key.
debug1: read PEM private key done: type DSA
debug1: private host key: #2 type 2 DSA
debug1: inetd sockets after dupping: 3, 3
debug3: Normalising mapped IPv4 in IPv6 address
Connection from 172.16.1.196 port 32801
debug1: Client protocol version 2.0; client software version OpenSSH_3.9p1
debug1: match: OpenSSH_3.9p1 pat OpenSSH_3.*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-1.99-OpenSSH_4.1
debug2: fd 3 setting O_NONBLOCK
debug3: privsep user:group 74:74
debug1: permanently_set_uid: 74/74
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_init: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug2: mac_init: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: Network child is on pid 20003
debug3: preauth child monitor started
debug3: mm_request_receive entering
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug3: mm_request_send entering: type 0
debug3: monitor_read: checking request 0
debug3: mm_answer_moduli: got parameters: 1024 1024 8192
debug3: mm_request_send entering: type 1
debug2: monitor_read: 0 used once, disabling now
debug3: mm_request_receive entering
debug3: mm_choose_dh: waiting for MONITOR_ANS_MODULI
debug3: mm_request_receive_expect entering: type 1
debug3: mm_request_receive entering
debug3: mm_choose_dh: remaining 0
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug2: dh_gen_key: priv key bits set: 122/256
debug2: bits set: 517/1024
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug2: bits set: 500/1024
debug3: mm_key_sign entering
debug3: mm_request_send entering: type 4
debug3: monitor_read: checking request 4
debug3: mm_answer_sign
debug3: mm_answer_sign: signature 0x89eeee8(143)
debug3: mm_request_send entering: type 5
debug2: monitor_read: 4 used once, disabling now
debug3: mm_request_receive entering
debug3: mm_key_sign: waiting for MONITOR_ANS_SIGN
debug3: mm_request_receive_expect entering: type 5
debug3: mm_request_receive entering
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user root service ssh-connection method none
debug1: attempt 0 failures 0
debug3: mm_getpwnamallow entering
debug3: mm_request_send entering: type 6
debug3: mm_getpwnamallow: waiting for MONITOR_ANS_PWNAM
debug3: mm_request_receive_expect entering: type 7
debug3: mm_request_receive entering
debug3: monitor_read: checking request 6
debug3: mm_answer_pwnamallow
debug3: auth_shadow_acctexpired: today 12922 sp_expire -1 days left -12923
debug3: account expiration disabled
debug3: mm_answer_pwnamallow: sending MONITOR_ANS_PWNAM: 1
debug3: mm_request_send entering: type 7
debug2: monitor_read: 6 used once, disabling now
debug3: mm_request_receive entering
debug2: input_userauth_request: setting up authctxt for root
debug3: mm_inform_authserv entering
debug3: mm_request_send entering: type 3
debug2: input_userauth_request: try method none
debug3: mm_auth_password entering
debug3: mm_request_send entering: type 10
debug3: mm_auth_password: waiting for MONITOR_ANS_AUTHPASSWORD
debug3: mm_request_receive_expect entering: type 11
debug3: mm_request_receive entering
debug3: monitor_read: checking request 3
debug3: mm_answer_authserv: service=ssh-connection, style=
debug2: monitor_read: 3 used once, disabling now
debug3: mm_request_receive entering
debug3: monitor_read: checking request 10
debug3: mm_answer_authpassword: sending result 0
debug3: mm_request_send entering: type 11
debug3: mm_auth_password: user not authenticated
Failed none for root from 172.16.1.196 port 32801 ssh2
Failed none for root from 172.16.1.196 port 32801 ssh2
debug3: mm_request_receive entering
Connection closed by 172.16.1.196
debug1: do_cleanup
debug1: do_cleanup

Re: SSH Host based Authentication setup

RAC_1 — Thu, 19 May 2005 09:58:31 GMT

It has to be setin .shosts and /etc/shosts.equiv and right perms.

Anil

Re: SSH Host based Authentication setup

Gopi Sekar — Thu, 19 May 2005 09:58:51 GMT

have you added /usr/local/etc/shosts.equiv (check the path from man ssh)

ssh requires this file when you have ~/.shosts file

Hope this helps,
Gopi

Re: SSH Host based Authentication setup

Ermin Borovac — Fri, 20 May 2005 06:46:16 GMT

Here's some notes to check. I think you got most of these, but you are possibly missing a step or two.

*** CLIENT ***

Make sure you have the following in ssh_config.

HostbasedAuthentication yes
PreferredAuthentications hostbased,publickey,password
EnableSSHKeysign yes

Make sure that ssh-keysign binary is setuid to root.

*** SERVER ***

Make sure you have the following in sshd_config

HostbasedAuthentication yes
IgnoreRhosts no

IgnoreRhosts is required for root account, as shosts.equiv does not work, so you have to use ~root/.shosts.

Create shosts.equiv (and .shosts for root only) with FQDN (i.e. the result of nslookup ) and optionally user name.

Create ssh_known_hosts from ssh_host_rsa_key.pub (please use public key NOT private key) and add host name at the beginning.

That's it and hope it works for you!

Re: SSH Host based Authentication setup

Michael Selvesteen_2 — Sat, 21 May 2005 00:17:15 GMT

Thank you all Folks for the great help. It's a matter of permissons and hostname look up issues.

Closing the thread !