Não é possível fazer login ssh no servidor remoto usando autenticação de chave pública

Question

Estou tentando fazer o login no servidor remoto usando o cliente ssh do Ubuntu, mas a autenticação de chave pública não funciona e me pede para digitar a senha do ssh.

Aqui está o relatório de depuração, não sei o que isso significa ...

OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to shell.gridhost.co.uk [185.52.26.190] port 22.
debug1: Connection established.
debug1: identity file /home/dipengrg/.ssh/id_rsa type 1
debug1: identity file /home/dipengrg/.ssh/id_rsa-cert type -1
debug1: identity file /home/dipengrg/.ssh/id_dsa type -1
debug1: identity file /home/dipengrg/.ssh/id_dsa-cert type -1
debug1: identity file /home/dipengrg/.ssh/id_ecdsa type -1
debug1: identity file /home/dipengrg/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/dipengrg/.ssh/id_ed25519 type -1
debug1: identity file /home/dipengrg/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
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<3072<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: Server host key: RSA 31:62:64:d1:f6:64:a7:4f:68:fe:80:97:34:37:0b:be
debug1: Host 'shell.gridhost.co.uk' is known and matches the RSA host key.
debug1: Found key in /home/dipengrg/.ssh/known_hosts:1
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,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

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

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available

debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/dipengrg/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Trying private key: /home/dipengrg/.ssh/id_dsa
debug1: Trying private key: /home/dipengrg/.ssh/id_ecdsa
debug1: Trying private key: /home/dipengrg/.ssh/id_ed25519
debug1: Next authentication method: password

    

Answer 1

O arquivo

authorized_keys não deve ser menos seguro que 600 , tente executar

$ chmod 600 $ ~/.ssh/authorized_keys

então você deve acabar com

-rw------- 1 serverAdmin serverAdmin  802 Nov 25 13:54 authorized_keys

(obviamente serverAdmin deve ser substituído pela conta de usuário que você está executando no servidor remoto)
O diretório .ssh também não pode ser menos seguro que 755 , por exemplo,

drwx------ 2 serverAdmin serverAdmin  4096 Jul 29 00:30 .ssh

Eu acho que é melhor usar ssh-copy-id para obter a chave pública no servidor remoto, pois ele lida com privilégios nos arquivos remotos