当 UsePAM 设置为“no”时，SSH 公钥身份验证失败

Question

要禁用密码身份验证，我在我的 sshd_config

ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no

当我尝试使用我的私钥登录时，我得到

Permission denied (publickey).

如果我然后更改UsePAM为yes我可以使用我的私钥登录。为什么？

我正在从 OSX 连接到 Ubuntu 12.04 64 位主机

ssh -i ~/.ssh/deploy -l deploy localhost -p 2222 -v

这是详细的ssh输出：

OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /Users/<user>/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to localhost [127.0.0.1] port 2222.
debug1: Connection established.
debug1: identity file /Users/<user>/.ssh/deploy type 1
debug1: identity file /Users/<user>/.ssh/deploy-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9
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: Server host key: RSA 50:db:75:ba:11:2f:43:c9:ab:14:40:6d:7f:a1:ee:e3
debug1: Host '[localhost]:2222' is known and matches the RSA host key.
debug1: Found key in /Users/<user>/.ssh/known_hosts:2
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
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/<user>/.ssh/key1
debug1: Authentications that can continue: publickey
debug1: Offering RSA public key: /Users/<user>/.ssh/deploy
debug1: Authentications that can continue: publickey
debug1: No more authentication methods to try.
Permission denied (publickey).

Answer 1

如果没有 PAM（可插入身份验证模块），则需要更复杂的 ssh 配置来进行身份验证。你正在寻找这个，实际上：

# grep Password /etc/ssh/sshd_config 
PermitEmptyPasswords no
PasswordAuthentication no

这将禁用密码登录。确保您正确建立了公钥设置。

Answer 2

您的用户帐户是否被锁定？您可以解锁用户帐户

passwd -u username

或锁定用户帐户但启用 PAM：

ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM yes