我的任务：从 Mac OS Snow Leopard 客户端无需密码登录到 Ubuntu 10.10 服务器。
命令：
client$ mkdir ~/.ssh
client$ chmod 700 ~/.ssh
client$ ssh-keygen -q -f ~/.ssh/id_rsa -t rsa
Enter passphrase (empty for no passphrase): [empty]
client$ chmod go-w ~/
client$ chmod 700 ~/.ssh
client$ chmod go-rwx ~/.ssh/*
client$ scp ~/.ssh/id_rsa.pub [email protected]:~
server$ mkdir ~/.ssh
server$ chmod 700 ~/.ssh
server$ cat ~/id_rsa.pub >> ~/.ssh/authorized_keys
server$ chmod 600 ~/.ssh/authorized_keys
server$ rm ~/id_rsa.pub
client$ ssh -o PreferredAuthentications=publickey server.domain.ltd
和...
Permission denied (publickey,password)。
调试输出（使用 -v）：
XX-XX-XXX-XXX:~ lorddaedra$ ssh -o PreferredAuthentications=publickey server.domain.ltd -v
OpenSSH_5.2p1, OpenSSL 0.9.8l 5 Nov 2009
debug1: Reading configuration data /etc/ssh_config
debug1: Connecting to server.domain.ltd [XXX.XX.XX.XX] port 22.
debug1: Connection established.
debug1: identity file /Users/lorddaedra/.ssh/identity type -1
debug1: identity file /Users/lorddaedra/.ssh/id_rsa type 1
debug1: identity file /Users/lorddaedra/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.5p1 Debian-4ubuntu5
debug1: match: OpenSSH_5.5p1 Debian-4ubuntu5 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.2
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 'server.domain.ltd' is known and matches the RSA host key.
debug1: Found key in /Users/lorddaedra/.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: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/lorddaedra/.ssh/identity
debug1: Offering public key: /Users/lorddaedra/.ssh/id_rsa
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /Users/lorddaedra/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey,password).
所以我的问题是我的错误在哪里以及如何解决它？谢谢！
附言
server$ cat /etc/ssh/sshd_config
# Package generated configuration file
# See the sshd_config(5) manpage for details
# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes
# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768
# Logging
SyslogFacility AUTH
LogLevel INFO
# Authentication:
LoginGraceTime 120
PermitRootLogin no
StrictModes yes
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile %h/.ssh/authorized_keys
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes
# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no
# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no
# Change to no to disable tunnelled clear text passwords
#PasswordAuthentication yes
# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
X11Forwarding no
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no
#MaxStartups 10:30:60
#Banner /etc/issue.net
# Allow client to pass locale environment variables
AcceptEnv LANG LC_*
Subsystem sftp /usr/lib/openssh/sftp-server
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication. Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
UseDNS no
AllowUsers lorddaedra
聚苯硫醚
server$ cat /var/log/auth.log
Feb 3 19:15:38 electra sudo: lorddaedra : TTY=pts/0 ; PWD=/home/lorddaedra ; USER=root ; COMMAND=/bin/cat /var/log/auth.log
Feb 3 19:16:01 electra CRON[19081]: pam_unix(cron:session): session opened for user lorddaedra by (uid=0)
Feb 3 19:16:01 electra CRON[19080]: pam_unix(cron:session): session opened for user lorddaedra by (uid=0)
Feb 3 19:16:02 electra CRON[19080]: pam_unix(cron:session): session closed for user lorddaedra
Feb 3 19:16:02 electra sshd[19088]: Authentication refused: bad ownership or modes for directory /home/lorddaedra
Feb 3 19:16:02 electra sshd[19088]: Authentication refused: bad ownership or modes for directory /home/lorddaedra
Feb 3 19:16:06 electra CRON[19081]: pam_unix(cron:session): session closed for user lorddaedra
Feb 3 19:16:07 electra sudo: lorddaedra : TTY=pts/0 ; PWD=/home/lorddaedra ; USER=root ; COMMAND=/bin/cat /var/log/auth.log
client$ ls -al /Users/lorddaedra/.ssh
total 40
drwx------ 6 lorddaedra staff 204 3 фев 01:54 .
drwxr-xr-x+ 183 lorddaedra staff 6222 31 янв 11:37 ..
-rw-------@ 1 lorddaedra staff 6148 21 ноя 2008 .DS_Store
-rw------- 1 lorddaedra staff 1675 3 фев 01:53 id_rsa
-rw------- 1 lorddaedra staff 427 3 фев 01:53 id_rsa.pub
-rw-r--r-- 1 lorddaedra staff 414 3 фев 01:54 known_hosts
server$ ls -al /home/lorddaedra/.ssh
итого 12
drwx------ 2 lorddaedra lorddaedra 4096 2011-02-03 01:55 .
drwxrwxr-x 13 lorddaedra lorddaedra 4096 2011-02-03 01:55 ..
-rw------- 1 lorddaedra lorddaedra 427 2011-02-03 01:55 authorized_keys
答案1
命令
sudo chmod -c g-w /home/lorddaedra
解决了我的问题。因此需要在用户主目录中将 775 更改为 755。如果有人知道 775 不好的原因，请发表评论。
答案2
就我而言，我发现 SELinux 是问题所在。
$ less /var/log/messages
Apr 20 00:16:12 vb-fc14-0 setroubleshoot: SELinux is preventing /usr/sbin/sshd from read access on the file authorized_keys. For complete SELinux messages. run sealert -l 174e87e8-bec5-4ae6-840c-44994ad5e2b3
$ sealert -l 174e87e8-bec5-4ae6-840c-44994ad5e2b3
SELinux is preventing /usr/sbin/sshd from read access on the file authorized_keys.
插件 sshd_root（置信度 91.4）建议：
如果您想允许 sshd 对 authorized_keys 文件具有读取权限，则必须修复标签。请执行以下操作：
/sbin/restorecon -Rv /root/.ssh
插件 catchall（置信度 9.59）建议：
如果您认为默认情况下应允许 sshd 对 authorized_keys 文件进行读取访问。那么您应该将此报告为错误。您可以生成本地策略模块以允许此访问。现在通过执行以下命令允许此访问：
$ grep sshd /var/log/audit/audit.log | audit2allow -M mypol
$ semodule -i mypol.pp
答案3
该.ssh目录不应是组可写的。命令
chmod g-w $HOME/.ssh
解决了我的问题。
答案4
我只是去/etc/ssh/sshd_config文件并编辑PasswordAuthentication值yes，在我的情况下它被设置为no
这为我解决了这个问题。