Getting Permission denied (publickey) even having my public key on the authorized_keys server file

Question

I accidentally erased my private and public key in my local machine.

So I created a new pair using:

ssh-keygen -t rsa

and copied the content of the id_rsa.pub into my authorized_keys on the server (I can log in as root and I can see the root public key in the authorized_keys file).

However, I keep getting Permission Denied. I already checked the ~/.ssh and the authorized keys permissions (which are set to 700 and 600 respectively).

Any ideas?

Thanks!

Here you have the log output when I try to connect from my local machine:

Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[16635]: debug1: Forked child 27356.
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: Set /proc/self/oom_score_adj to 0
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: rexec start in 5 out 5 newsock 5 pipe 7 sock 8
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: inetd sockets after dupping: 3, 3
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: Connection from 50.67.165.140 port 60112
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: Client protocol version 2.0; client software version OpenSSH_5.9p1 Debian-5ubuntu1.1
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1.1 pat OpenSSH*
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: Enabling compatibility mode for protocol 2.0
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: permanently_set_uid: 105/65534 [preauth]
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: list_hostkey_types: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256 [preauth]
Aug 21 16:32:27 ip-xx-xx-xx-xx sshd[27356]: debug1: SSH2_MSG_KEXINIT sent [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: SSH2_MSG_KEXINIT received [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: kex: client->server aes128-ctr hmac-md5 none [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: kex: server->client aes128-ctr hmac-md5 none [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: SSH2_MSG_NEWKEYS sent [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: expecting SSH2_MSG_NEWKEYS [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: SSH2_MSG_NEWKEYS received [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: KEX done [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: userauth-request for user capistrano service ssh-connection method none [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: attempt 0 failures 0 [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: PAM: initializing for "capistrano"
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: PAM: setting PAM_RHOST to "s0106c8fb26427cda.vc.shawcable.net"
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: PAM: setting PAM_TTY to "ssh"
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: userauth-request for user capistrano service ssh-connection method publickey [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: attempt 1 failures 0 [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: test whether pkalg/pkblob are acceptable [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: temporarily_use_uid: 1001/1001 (e=0/0)
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: trying public key file /home/capistrano/.ssh/authorized_keys
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: fd 4 clearing O_NONBLOCK
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: restore_uid: 0/0
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: Failed publickey for capistrano from <ip> port 60112 ssh2
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: Connection closed by <ip> [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: do_cleanup [preauth]
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: monitor_read_log: child log fd closed
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: do_cleanup
Aug 21 16:32:28 ip-xx-xx-xx-xx sshd[27356]: debug1: PAM: cleanup

Answer 1

Delete the known_hosts entry for your workstation and try again. I use 644 for authorized_keys.

Answer 2

What users and paths are involved? In the standard openssh setup, the $HOME/.ssh directory of the remote user (the one into which ssh is logging in) is the right location for the authorized_keys file. However, it is also possible to have the files located elsewhere.

Also, check the file ownership. The authorized_keys file must be owned by the user logging in.

A check of /var/log/messages or /var/log/secure ("ls -ltr /var/log" after a failed attempt may help figure out the right log file) may give specifics.

If all else fails, you could strace the sshd process(es) to see exactly which files they are reading. Not trivial to do, but it does get right to the guts of the operation of the server.

Answer 3

What works for me is:

chmod 750 /home/user
chmod 700 /home/user/.ssh
chmod 644 /home/user/.ssh/authorized_keys

If that doesn't work for you, try:

chmod 755 /home/user

Answer 4

Ok so I figure it out... the issue was that I was adding the public key to the authorized_keys file on another user's directory. :S.. Thanks anyway