GitLab SSH Keys - Permission denied (publickey)

I followed this document to setup my SSH authentication https://kgcoe-git.rit.edu/help/ssh/README#generating-a-new-ssh-key-pair

It has worked before but this time on a new setup I get Permission denied (publickey) error

Below is the debug output from the ssh command

ankushko@node-0:~/Code$ sudo ssh -vT git@pc3.instageni.utc.edu
OpenSSH_7.2p2 Ubuntu-4ubuntu2.4, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to pc3.instageni.utc.edu [150.182.135.23] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to pc3.instageni.utc.edu:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-rsa SHA256:BUPmhA1nWbH8Zq0cg4uohS3L/Vo4uOZ8PLrdUYf3ano
debug1: Host 'pc3.instageni.utc.edu' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Trying private key: /root/.ssh/id_ecdsa
debug1: Trying private key: /root/.ssh/id_ed25519
debug1: No more authentication methods to try.
Permission denied (publickey).

Keys

ankushko@node-0:~$ sudo ls ~/.ssh/
authorized_keys  id_rsa  id_rsa.pub  known_hosts

Update: Tried without sudo

ankushko@node-0:~$ ssh -vT git@pc3.instageni.utc.edu
OpenSSH_7.2p2 Ubuntu-4ubuntu2.4, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to pc3.instageni.utc.edu [150.182.135.23] port 22.
debug1: Connection established.
debug1: identity file /users/ankushko/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /users/ankushko/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to pc3.instageni.utc.edu:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-rsa SHA256:BUPmhA1nWbH8Zq0cg4uohS3L/Vo4uOZ8PLrdUYf3ano
debug1: Host 'pc3.instageni.utc.edu' is known and matches the RSA host key.
debug1: Found key in /users/ankushko/.ssh/known_hosts:1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /users/ankushko/.ssh/id_rsa
debug1: Authentications that can continue: publickey
debug1: Trying private key: /users/ankushko/.ssh/id_dsa
debug1: Trying private key: /users/ankushko/.ssh/id_ecdsa
debug1: Trying private key: /users/ankushko/.ssh/id_ed25519
debug1: No more authentication methods to try.
Permission denied (publickey).

Thanks in advance.

1 answer

  • answered 2018-11-11 19:38 bitinerant

    The command:

    sudo ssh -vT git@pc3.instageni.utc.edu
    

    is running as root and will use /root/.ssh/config and a private ssh key from that same directory, e.g. /root/.ssh/id_rsa. In the command:

    sudo ls ~/.ssh/
    

    the shell, probably bash, will expand ~ to your home directory before it even calls sudo (prove this with sudo echo ~), so it will display files from your home directory, probably /home/ankushko.

    Can I ask why you are running these command with sudo? Would it work to just connect as a normal user? That would be more secure, but sometimes there is a need to run things as root.

    Either way, you need to make sure the private ssh key that you are actually using matches the public ssh key on the server.