Unable to use pub/private keys with ssh

AncientPC · 07-24-2009, 03:49 PM

I generated a new key with ssh-keygen, then cat'ed the .pub to ~/.ssh/authorized_keys. Confirmed /etc/ssh/sshd_config contains:

Quote:

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys

I restart the ssh daemon and run `ssh -i test_key localhost`, but am still prompted for a password. I added the private key to my ssh agent with `ssh-add test_key` and confirm with `ssh-add -L`, but still get a password when trying to ssh locally. Can anyone help explain why?

jhwilliams · 07-24-2009, 04:03 PM

Quote:

Originally Posted by AncientPC

I generated a new key with ssh-keygen, then cat'ed the .pub to ~/.ssh/authorized_keys. Confirmed /etc/ssh/sshd_config contains:

I restart the ssh daemon and run `ssh -i test_key localhost`, but am still prompted for a password. I added the private key to my ssh agent with `ssh-add test_key` and confirm with `ssh-add -L`, but still get a password when trying to ssh locally. Can anyone help explain why?

Not much of an idea, but here's a morsel:
Did you create an RSA or a DSA key with the keygen? id_rsa.pub or id_dsa.pub? Haven't looked at the config for this ever, but usually both are accepted.

thinknix · 07-24-2009, 04:38 PM

Unless you made a typo, you want this:

Code:

AuthorizedKeysFile     %h/.ssh/authorized_keys

But you can actually comment that line out and the default will be the same value.

AncientPC · 07-24-2009, 04:44 PM

Quote:

Originally Posted by jhwilliams

Not much of an idea, but here's a morsel:
Did you create an RSA or a DSA key with the keygen? id_rsa.pub or id_dsa.pub? Haven't looked at the config for this ever, but usually both are accepted.

The default which is rsa.

Quote:

Originally Posted by slugmax

Unless you made a typo, you want this:

Code:

AuthorizedKeysFile     %h/.ssh/authorized_keys

But you can actually comment that line out and the default will be the same value.

I commented out, restarted sshd, still no go. Added it back in with the %h, restarted sshd, same problem.

acid_kewpie · 07-24-2009, 04:47 PM

The most common gotcha I find is the rights on ~/.ssh, which should be 600 (or 700), but often 640 by default.

thinknix · 07-24-2009, 04:58 PM

Try this:

Code:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
ssh -v -i test_key localhost

Also, if your private key is in ~/.ssh/id_rsa, you don't need the '-i'.

AncientPC · 07-27-2009, 10:57 AM

Permissions:
.ssh/ 755
.ssh/authorized_keys 544

It looks like the key is getting properly authenticated but ssh is running into an unspecified GSS failure. Unfortunately it still prompts me for a password and I can't seem to find what's causing the "No credentials cache found."

Quote:

root@d31lin08:~# ssh -vi test localhost
OpenSSH_4.3p2, OpenSSL 0.9.8b 04 May 2006
debug1: Reading configuration data /root/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file test type 1
debug1: loaded 1 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
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
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'localhost' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:4
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Next authentication method: publickey
debug1: Offering public key: test
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: password
root@localhost's password:

When I disable GSS authentication, it still fails:

Quote:

OpenSSH_4.3p2, OpenSSL 0.9.8b 04 May 2006
debug1: Reading configuration data /root/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file test type 1
debug1: loaded 1 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
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
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'localhost' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:4
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: publickey
debug1: Offering public key: test
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: password

acid_kewpie · 07-27-2009, 01:24 PM

Hmm..... tricky.... did you try actually reading the last two posts at all?

AncientPC · 07-28-2009, 01:33 PM

Quote:

Originally Posted by acid_kewpie

Hmm..... tricky.... did you try actually reading the last two posts at all?

Yes, which is why I replied with the current permissions. Just for testing sake I chmod -R .ssh/ to 777 and it still gives me the same error.

custangro · 07-28-2009, 01:41 PM

Quote:

Originally Posted by AncientPC

Yes, which is why I replied with the current permissions. Just for testing sake I chmod -R .ssh/ to 777 and it still gives me the same error.

You obviously didn't...read slugmax's post...and TRY IT...also the permissions are tricky...using 777 will actually break it...the perms on the key files are tricky and has to be exact...

Post when you actually tried what slugmax suggested.

-C

acid_kewpie · 07-28-2009, 03:29 PM

OK, so no, you didn't read them. I didn't think so.

The
rights
should
be
600

;-)

AncientPC · 07-28-2009, 03:48 PM

I changed .ssh/ to 700, .ssh/authorized_keys to 600 and it still fails.

I then generated another key pair and used ssh-copy-id (which sets proper permissions) to copy the id file over and ssh using keys still fails.

For what it's worth, here's my /etc/ssh/sshd_config:

Quote:

# $OpenBSD: sshd_config,v 1.73 2005/12/06 22:38:28 reyk Exp $

# This is the sshd server system-wide configuration file. See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Uncommented options change a
# default value.

#Port 22
Protocol 2
Protocol 2
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::

# HostKey for protocol version 1
#HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key

# Lifetime and size of ephemeral version 1 server key
#KeyRegenerationInterval 1h
#ServerKeyBits 768

# Logging
# obsoletes QuietMode and FascistLogging
#SyslogFacility AUTH
SyslogFacility AUTHPRIV
#LogLevel INFO

# Authentication:

#LoginGraceTime 2m
PermitRootLogin yes
#StrictModes yes
#MaxAuthTries 6

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile %h/.ssh/authorized_keys

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#RhostsRSAAuthentication no
# similar for protocol version 2
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
PasswordAuthentication yes

# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication no

# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no

# GSSAPI options
#GSSAPIAuthentication no
GSSAPIAuthentication yes
#GSSAPICleanupCredentials yes
GSSAPICleanupCredentials yes

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication mechanism.
# Depending on your PAM configuration, this may bypass the setting of
# PasswordAuthentication, PermitEmptyPasswords, and
# "PermitRootLogin without-password". If you just want the PAM account and
# session checks to run without PAM authentication, then enable this but set
# ChallengeResponseAuthentication=no
#UsePAM no
UsePAM yes

# Accept locale-related environment variables
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#ShowPatchLevel no
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10
#PermitTunnel no

# no default banner path
#Banner /some/path

# override default of no subsystems
Subsystem sftp /usr/libexec/openssh/sftp-server

acid_kewpie · 07-28-2009, 03:55 PM

stick a few -v's on the ssh command line and post the output.

AncientPC · 07-28-2009, 04:01 PM

Some output:

Quote:

pubuntu@pubuntu:~/.ssh$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/pubuntu/.ssh/id_rsa): test2
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in test2.
Your public key has been saved in test2.pub.
The key fingerprint is:
d7:ec:90:5b:b0:e4:f5:ee:fc:a1:b9:0d:d4:fc:81:8b pubuntu@pubuntu
pubuntu@pubuntu:~/.ssh$ ssh-copy-id -i test2 root@linbox
root@linbox's password:
Now try logging into the machine, with "ssh 'root@linbox'", and check in:

.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

pubuntu@pubuntu:~/.ssh$ ssh -vi test2 root@linbox
OpenSSH_4.7p1 Debian-8ubuntu1.2, OpenSSL 0.9.8g 19 Oct 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to linbox [9.48.174.60] port 22.
debug1: Connection established.
debug1: identity file test2 type 1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.7p1 Debian-8ubuntu1.2
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
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
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'linbox' is known and matches the RSA host key.
debug1: Found key in /home/pubuntu/.ssh/known_hosts:4
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information

debug1: Next authentication method: publickey
debug1: Offering public key: test2
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: password
root@linbox's password:

AncientPC · 07-28-2009, 04:07 PM

I just realized what could be causing the problem:

Quote:

AuthorizedKeysFile %h/.ssh/authorized_keys

root's home directory on the RHEL box is at /root/, not /home/root/ so sshd is looking in the wrong place for the authorized keys file.

I created /home/root/ and sym-linked to .ssh/ but that didn't work. Copied .ssh/ over to /home/root/ but that didn't work either.

Then I hardcoded the authorizedkeysfile to /root/.ssh/authorized and restarted sshd, but that didn't resolve the issue either.

A couple more verbose flags:

Quote:

root@d31lin08:~# ssh -vvvi test localhost
OpenSSH_4.3p2, OpenSSL 0.9.8b 04 May 2006
debug1: Reading configuration data /root/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug3: Not a RSA1 key file test.
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 test type 1
debug1: loaded 1 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
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,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: 137/256
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 'localhost' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:4
debug2: bits set: 477/1024
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: test (0x83267c8)
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug3: start over, passed a different list publickey,gssapi-with-mic,password
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug3: Trying to reverse map address 127.0.0.1.
debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found

debug2: we did not send a packet, disable method
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: test
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
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
root@localhost's password: