ssh access with key authentication does not work

1

I'm trying to set a no-password connection throw two servers, the first (A) runs Win server with Cygwin and the second runs Debian Linux. I followed this guide: http://troy.jdmz.net/rsync/index.html, so:

1.DEB server

1.a. created keys:

ssh-keygen -t rsa -b 2048 -f /home/deb-user/cron/deb-rsync-key

1.b copied deb-rsync-key.pub on the Win server using scp & authentication

2.Win server

2.a entered the Win server using ssh and authentication and moved deb-rsync-key.pub in the .ssh folder and then copied the content in the authorized_keys file, that I created

2.b made sure that .ssh folder had 700 permission and authorized_keys file 600.

2.c made sure that RSAAuthentication and PubkeyAuthentication keys in /etc/sshd/sshd_config were both uncommented and yes

2.d Tried to set the AuthorizedKeysFile as absolute path pointing to the autorized_keys file in the user's home folder (changed from .ssh/autorized_keys to /home/win-user/.ssh/autorized_keys)

2.e restarted sshd server (net stop sshd, net start sshd)

3.Deb server

Trying to access the win server using the key:

ssh -i /home/deb-user/cron/deb-rsync-key win-user@win-host

all I get is

Connection closed by win-host

Nothing is logged in DEB: /var/logs/auth.log

Nothing is logged in WIN: /var/logs/sshd.log

Any help will be much appreciated!

UPDATE: adding -v option in ssh command returns this:

OpenSSH_5.5p1 Debian-6+squeeze3, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to win-host [win-host] port 22.
debug1: Connection established.
debug1: identity file /home/deb-user/cron/deb-rsync-key.pub type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/deb-user/cron/deb-rsync-key.pub-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.0
debug1: match: OpenSSH_6.0 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-6+squeeze3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'win-host' is known and matches the RSA host key.
debug1: Found key in /home/deb-host/.ssh/known_hosts:2
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Offering public key: /home/deb-host/cron/deb-rsync-key.pub
Connection closed by win-host

UPDATE2 win server .ssh folder permissions are as follows:

$ ls -la .ssh
total 6
drwx------+ 1 win-user Domain Users   0 Mar 12 10:26 .
drwxr-xr-x+ 1 win-user Domain Users   0 Mar 12 10:25 ..
-rw-------  1 win-user Domain Users 396 Mar 12 10:26 authorized_keys
-rw-------  1 win-user Domain Users 396 Mar 12 10:24 deb-rsync-key.pub

UPDATE3: folder permissions in DEB server are as follows:

$ ls -la /home/
total 16
drwxr-xr-x  4 root  root  4096 31 gen 11.19 .
drwxr-xr-x 22 root  root  4096 28 gen 11.59 ..
drwx------ 18 deb-user deb-user 4096 12 mar 11.15 deb-user

And folder permissions in Win server as follows:

$ ls -la /home/
total 8
drwxrwxrwt+ 1 jbogdani root         0 Oct 20  2011 .
drwxr-xr-x+ 1 jbogdani root         0 Nov  1 00:44 ..
drwx------+ 1 win-user Domain Users 0 Mar 12 10:25 win-user

UPDATE4 More verbose:

$ ssh -vvv -i /home/de-user/cron/deb-rsync-key win-user@win-host
OpenSSH_5.5p1 Debian-6+squeeze3, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to win-host [win-host] port 22.
debug1: Connection established.
debug3: Not a RSA1 key file /home/deb-user/cron/deb-rsync-key.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/deb-user/cron/deb-rsync-key type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/deb-user/cron/deb-rsync-key-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.0
debug1: match: OpenSSH_6.0 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-6+squeeze3
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,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: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr 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: 139/256
debug2: bits set: 528/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: host win-host filename /home/deb-user/.ssh/known_hosts
debug3: check_host_in_hostfile: host win-host filename /home/deb-user/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug1: Host 'win-host' is known and matches the RSA host key.
debug1: Found key in /home/deb-user/.ssh/known_hosts:2
debug2: bits set: 506/1024
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: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/deb-user/cron/deb-rsync-key (0xb8f465c0)
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug3: start over, passed a different list publickey,password,keyboard-interactive
debug3: preferred gssapi-keyex,gssapi-with-mic,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: Offering public key: /home/deb-user/cron/deb-rsync-key
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
Connection closed by win-host

bradypus

Posted 2013-03-12T09:54:15.940

Reputation: 113

Try ssh'ing with the -v argument, for added verbosity – None – 2013-03-12T09:58:50.087

Updated with verbose result of ssh command – None – 2013-03-12T10:12:20.503

If you wouldn't mind, the output for "ls -la /home/win-user/.ssh", so we can see if you have the right permissions – None – 2013-03-12T10:15:56.953

@brian Updated! – None – 2013-03-12T10:21:16.067

Answers

0

I would think the problem is in your authorized_keys, or possibly that you don't have rsync installed on the server.

Check if rsync is installed first, then let's try to solve the problem in steps:

First, let's get rid for from= and command=, that way we can see if it can connect using the key at all.

The resulting line in should look like this:

ssh-dss AAAAB3NzaC1kc3MAAAEBA ..

Then let's see if we can connect using ssh directly.

ssh -i [path-to-key] win-user@win-host

If that works, let's add ip=, make sure it's the IP of the client connecting.

ip="[client-ip]" ssh-dss AAAAB3NzaC1kc3MAAAEBA ..

Try to connect again using the ssh command above.

Lastly, let's add our validate-rsync.

ip="[client-ip]",command="/home/remoteuser/cron/validate-rsync" ssh-dss AAAAB3NzaC1kc3MAAAEBA ..

Now, with the use of /home/remoteuser/cron/validate-rsync, you won't be able to use ssh directly, as it's the script prevents the default shell (defined in /etc/passwd).

validate-rsync is used to prevent all commands except rsync --server. Instead, you should try a simple rsync from client to server.

touch test && rsync -vv -e "ssh -i path-to-key" test win-user@win-host

It can also be cygwin-related, please check out this message:

http://cygwin.com/ml/cygwin/2008-08/msg00155.html.

brain

Posted 2013-03-12T09:54:15.940

Reputation: 116

Hello, in the tutorial I quoted I've not gone further the steps I described above. Rsync is installed and works correctly using password. I've not added filters (from= or command+) in the authorized_keys files. I can ssh correctly using password, but I get the errors i described if I try to ssh using the key file. It means I'm not able to get ssh -i [path-to-key] win-user@win-host work at all. Double checked files and folders permission in Win and Deb servers: everything seems to be OK.... – None – 2013-03-12T13:05:10.830

Please check for details UPDATE3 in my question. – None – 2013-03-12T13:11:05.020

Check authorized_keys and see if it's valid. Make sure there are no newlines in the middle of the public key (happens easily when you copy-paste between two terminals), and make sure you got the whole public key. – None – 2013-03-12T13:12:47.127

Public key is identical in both server: same content, no newlines, etc... I just double-checked..... – None – 2013-03-12T13:22:38.593

Try ssh again, using -vvv for even more verbosity =) – None – 2013-03-12T13:27:34.557

Thank you for your patience ;) Check UPDATE 4 for more details. – None – 2013-03-12T13:33:55.147

debug3: Not a RSA1 key file /home/deb-user/cron/deb-rsync-key. Please make sure that's a valid private key. When you generated the keypair you got (for example) id_rsa and id_rsa.pub. The .pub file is the public key, and should be in the authorized_keys at the host, and other file is the private key. – None – 2013-03-12T13:37:01.927

But it is there... I have the /home/deb-user/cron/deb-rsync-key and I can open it correctly. I'll try to recreate it.... But I've already done this several times already.... – None – 2013-03-12T13:43:42.717

The only think I can think of now is that it's cygwin-related. Check out this message: http://cygwin.com/ml/cygwin/2008-08/msg00155.html. Make sure you run ssh-host-config, and all that.

– None – 2013-03-12T13:46:27.947

@brian Thank you very much! It WAS a cygwin related issue. Following your link I did solve my problem and was able to ssh (and rsync) passwordless! – bradypus – 2013-03-13T06:51:09.820

Asked: 2013-03-12T09:54:15.940

Viewed: 2 997 times

Active: 2013-03-12T13:55:04.673