opensshd / openssh - 允許密鑰對或密碼

我想將我的 sshd 配置為允許使用者使用密鑰對進行身份驗證，然後回退到密碼身份驗證。但是我正在努力從手冊頁/ sshd_config 文件中的資訊中實現這一目標。

我的 sshd_config：

Protocol 2
SyslogFacility AUTHPRIV
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile      .ssh/authorized_keys
PasswordAuthentication yes
ChallengeResponseAuthentication no
GSSAPIAuthentication yes
GSSAPICleanupCredentials yes
UsePAM yes
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
X11Forwarding yes
Subsystem       sftp    /usr/libexec/openssh/sftp-server

當我連接時，似乎正在發送私鑰 - 但仍然提示我輸入密碼：

[colinm@server bin]$ ssh -v colinm@dev-server
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to dev-server [10.168.172.81] port 22.
debug1: Connection established.
debug1: identity file /home/colinm/.ssh/identity type -1
debug1: identity file /home/colinm/.ssh/id_rsa type 1
debug1: identity file /home/colinm/.ssh/id_dsa type -1
debug1: loaded 3 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-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr 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 'dev-server' is known and matches the RSA host key.
debug1: Found key in /home/colinm/.ssh/known_hosts:10
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: Trying private key: /home/colinm/.ssh/identity
debug1: Offering public key: /home/colinm/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Trying private key: /home/colinm/.ssh/id_dsa
debug1: Next authentication method: password
colinm@dev-server's password:

是否可以讓伺服器接受 EITHER 作為身份驗證機制？

（是的，公鑰被複製到~/.ssh/authorized_keys，我用這個配置重啟了sshd）。

更多調試顯示密鑰對沒有失敗：

...
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/colinm/.ssh/identity
debug3: no such identity: /home/colinm/.ssh/identity
debug1: Offering public key: /home/colinm/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Trying private key: /home/colinm/.ssh/id_dsa
debug3: no such identity: /home/colinm/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password

通常sshd確實允許公鑰身份驗證、密碼身份驗證和您啟用的其他身份驗證。從您的輸出中，您可以看到首先嘗試了 GSSAPI，但沒有成功。接下來提供了公鑰，但沒有被接受，最後密碼驗證要求您輸入密碼。如果您輸入了錯誤的密碼（或者該帳戶的登錄被禁用），它將失敗，您將一無所有。

儘管您已將公鑰上傳到~/.ssh/authorized_keys文件中，但這還不足以讓密鑰身份驗證正常工作。該sshd服務的權限也相當嚴格。目錄~/.ssh的模式應該是 700，文件的模式應該是 600。目錄的所有者~/.ssh應該是使用者本身，而不是 root 或其他任何人。

引用自：https://unix.stackexchange.com/questions/226079