SSH添加了公钥总是需要询问密码
针对此类问题首先可以在客户端使用ssh -vT [email protected]来展示更详细的ssh过程，但是这通常无法得到更多有用的信息，此时可以尝试在目标机器上tail -f /var/log/secure来查看ssh的日志信息。
# ssh -vT [email protected]
OpenSSH_for_Windows_7.7p1, LibreSSL 2.6.5
debug1: Reading configuration data C:\\Users\\Fat Tiger/.ssh/config
debug1: Connecting to git.jackyzhong.com [47.102.116.218] port 22.
debug1: Connection established.
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_ed25519-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_xmss type -1
debug1: key_load_public: No such file or directory
debug1: identity file C:\\Users\\Fat Tiger/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_for_Windows_7.7
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.0
debug1: match: OpenSSH_8.0 pat OpenSSH* compat 0x04000000
debug1: Authenticating to git.jackyzhong.com:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:pkY5IbHPHc5IBKjcHV01CTCR6YOPxXjTyOuYThvWh2w
debug1: Host 'git.jackyzhong.com' is known and matches the ECDSA host key.
debug1: Found key in C:\\Users\\Fat Tiger/.ssh/known_hosts:52
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: pubkey_prepare: ssh_get_authentication_socket: No such file or directory
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:zVBT1hcHvvBpj1+85qPdUDu96JAF8uTCFhFeqxiOW3w C:\\Users\\Fat Tiger/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Trying private key: C:\\Users\\Fat Tiger/.ssh/id_dsa
debug1: Trying private key: C:\\Users\\Fat Tiger/.ssh/id_ecdsa
debug1: Trying private key: C:\\Users\\Fat Tiger/.ssh/id_ed25519
debug1: Trying private key: C:\\Users\\Fat Tiger/.ssh/id_xmss
debug1: Next authentication method: password
debug1: read_passphrase: can't open /dev/tty: No such file or directory
# tail -f /var/log/secure
Jun 16 22:23:33 sshd[20543]: Authentication refused: bad ownership or modes for directory xxxxxx
Jun 16 22:23:35 sshd[20543]: Connection reset by authenticating user xxxxx port 2016 [preauth]
另外在Centos上.ssh目录需要700权限而authorized_keys文件需要600权限，权限过高或过低都会导致ssh失败，也可以通过修改ssh_config文件设置StrictModes off取消此限制，但是没必要，修复权限通常是正确的做法。
