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-   -   Backuppc : ssh always ask for password (http://www.howtoforge.com/forums/showthread.php?t=19550)

Trollineto 17th January 2008 15:43

Backuppc : ssh always ask for password
 
Hello
I'm trying to backup a linux box (etch) on a backuppc server (etch too) but ssh always ask me for a password.
I've followed your howto as others (backuppc's faq...), and I don't know where I missed.
Any Idea ?
Tx
Vincent

falko 18th January 2008 18:54

In the ~/.ssh/authorized_keys2 file on the client, you have something like
Code:

from="server1.example.com" ssh-rsa AAAAB3[...]FMZpdAj8Hs9107tZ97Rq2oO/Zw== backuppc@server1.example.com
Please remove the
from="server1.example.com"
at the beginning. Does it work then?

brunus 19th March 2008 09:54

Hi Falko,
I have the exact same problem as Trollineto. I've tried your hint, but no success.
I've gone thru your backuppc 4 times scupolously, with my colleagues controlling me to be sure I didn't make any mistakes or typos, and I end up always with the same issue. Strangely when i did it the first time it worked perfectly, then all of a sudden backuppc stopped working because it can't establish the ssh connection anymore. So i've tried to rebuild the ssh tunnel again, following your instructions on point 5 of your how-to, but no luck. It's like the backuppc server not being able to find the authorized key entry on the client.
Is there any log I can check to find out the problem?

thanks

Paolo

brunus 20th March 2008 10:54

I'm losing my mind on this damn ssh key exchange!
I've reinstalled both the openssh server and client on both the server and the client to be backed up, config files included. Still, I can't get to have it working.

Here's is the output of the ssh -vvvv command: please, do help me understand what's wrong.

thanks,

paolo

backuppc@fileserver:~# ssh -l root -vvvv 192.168.1.1 whoami
OpenSSH_4.6p1 Debian-5ubuntu0.1, OpenSSL 0.9.8e 23 Feb 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.1.1 [192.168.1.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
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 /root/.ssh/id_rsa type 1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version
OpenSSH_4.2p1 Debian-7ubuntu3.2
debug1: match: OpenSSH_4.2p1 Debian-7ubuntu3.2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.6p1 Debian-5ubuntu0.1
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,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
cbc,arcfour128,arcfour256,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,arcfour128,arcfour256,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@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: 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,arcfour128,arcfour256,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,arcfour128,arcfour256,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@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_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: 117/256
debug2: bits set: 504/1024
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 4
debug1: Host '192.168.1.1' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:4
debug2: bits set: 523/1024
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 (0x800575b0)
debug2: key: /root/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-
mic,gssapi,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: /root/.ssh/identity
debug3: no such identity: /root/.ssh/identity
debug1: Offering public key: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /root/.ssh/id_dsa
debug3: no such identity: /root/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password

falko 20th March 2008 15:03

What's in the ~/.ssh/authorized_keys2 file on the client?

brunus 20th March 2008 15:18

root@efbujagateway:~# cat /root/.ssh/authorized_keys2
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA1QqZnL3d4vRGHuz1DI9Tmm PaOpeDAfoY1KQdOBuA5frk7xL8jGCKsL/LsPj/+jPsPbNTDelIasXI2ymXvU4m3sgcMsKNeYk9HUKKh4pZc5cR9j NMVpRHuLvpWdz7M2kBRS61j+L/ZgMeVKsnKHwriClmaJv91Z5p16rAkOFB3Cr4+fc3/sgFse/gNqVP+EeAicExfPEbOozr8/sfP+W9MJj37O8nc9glZWyzUtS8mNdQhzEkYqaCqDttXuk3bfwl dCeOzU8GifKivDOe/u4S4Ls2xcizHCKLbMjA40a4Cf3mWajYTPCZUE219Q4GCkLdQ60 C+u/5vOr5JSFa/xaX/w== backuppc@fileserver
ssh-dss AAAAB3NzaC1kc3MAAACBALoqHetSNJKsVfNZ5uOtK87VyBEwRm xYwfTk/eCOxWEhmRw0d6JU6OxMSgUsL1gTS6GaiZMUjO9kqPXUDVFR+E1 as4pIMscaJz610jEGl1MI6duoyTMHtt5d8ZDlviidH4dANf0Bq J40aq5QlcBUi9M10rEOJNVJFbsqrJThQGOlAAAAFQC7XTPyTlG xCjsgZk2hIgOaktUVUQAAAIEApcDlWXJ9+xDbJ5ScmicDEcUc3 oPZn+4KcilwuCUJtjnA3IdPZzvT4grHVEl8UxiAS/ZaxlXsfTdsqSG071WL4aEE3qWIcI5bxvYbQrQA2FjQbwNTid+9 bQizAfBjOGWwAD4+Mi6XoBOKC+SVahKCuoUybaW/wI349KDYvxZOwqUAAACBAIxarcDdRLO3zw+bO7orHeSATI/r4kF9bGZLESbTE/4gzMKKb3pitvjaraE5MhhUsmkuj5gakGvtcNTvNYz76lLHLKHt ab2LCblIcA6hYbYha6xErx1IUfPTPBNdDxBuNvyQ9PRLqj9o3m YzQmrxIeymVKrl8DYLKppOlbWjEBCG backuppc@fileserver

I've tried also with ssh-keygen -t dsa, no hope.

paolo

PS
I add that I'm using the client machine (efbujagateway The perfect Ubuntu Server 6.06.1) in recovery mode.

brunus 20th March 2008 18:35

gotcha!

Looking at auth.log on my server revealed the problem: sshd was
refusing to use my public key because my home directory was
group-writable. In order to do pubkey auth, both the home directory
and the .ssh directory must writable only by the owner.

still, my backup restore fails with a Unable to read 4 bytes error :(

Paolo

falko 21st March 2008 13:51

Quote:

Originally Posted by brunus
still, my backup restore fails with a Unable to read 4 bytes error :(

On the server or the client?
Which distribution are you using?

brunus 21st March 2008 15:00

hi,
as stated earlier, the client is a 'Perfect' Ubuntu Server 6.06.1, called efbujagateway.
Backuppc is installed on a fileserver.
When I look at backuppc's error log for efbujagateway, here's what I read:

efbujagateway
efbujagateway Accueil Explorer les sauvegardes Fichier journal Fichiers journaux Bilan des derniers transferts échoués Bilan des derniers transferts échoués (erreurs seulement) Modifier la configuration
Fichier /media/disk/backups/pc/efbujagateway/XferLOG.bad.z (Extraction des erreurs seulement)

Contenu du fichier /media/disk/backups/pc/efbujagateway/XferLOG.bad.z, modifié le 2008-03-21 04:00:06 (Extraction des erreurs seulement)

full backup started for directory / (baseline backup #25)
Running: /usr/bin/ssh -q -x -l root efbujagateway /usr/bin/rsync --server --sender --numeric-ids --perms --owner --group -D --links --hard-links --times --block-size=2048 --recursive --ignore-times . /
Xfer PIDs are now 28618
Read EOF: Connection reset by peer
Tried again: got 0 bytes
Done: 0 files, 0 bytes
Got fatal error during xfer (Unable to read 4 bytes)
Backup aborted (Unable to read 4 bytes)

and for the restore:

Fichier /media/disk/backups/pc/efbujagateway/RestoreLOG.12.z (Extraction des erreurs seulement)

Contenu du fichier /media/disk/backups/pc/efbujagateway/RestoreLOG.12.z, modifié le 2008-03-21 15:58:26 (Extraction des erreurs seulement)

Running: /usr/bin/ssh -q -x -l root efbujagateway /usr/bin/rsync --server --numeric-ids --perms --owner --group -D --links --hard-links --times --block-size=2048 --relative --ignore-times --recursive . /
Xfer PIDs are now 15583
Read EOF: Connection reset by peer
Tried again: got 0 bytes
Done: 0 files, 0 bytes
restore failed: Unable to read 4 bytes

I repeat that the client machine is running in recovery mode, because permissions have been accidentally screwed up (sudo chmod 777 / ).
Plus I'm wondering whether some needed services are off and should be on.

paolo

brunus 21st March 2008 16:48

SOLVED!

Sorry Falko,
with all this mess with ssh, I had still to readd once more the client to the backuppc server known_hosts file. Once it done, it started working again.

thanks,

Paolo


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