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Linux无法登陆,var目录权限修改导致SSH失败

Linux无法登陆,var目录权限修改导致SSH失败

作者: 木木与呆呆 | 来源:发表于2019-04-10 13:20 被阅读0次

    1.问题说明

    Linux远程服务器突然无法SSH登录了,
    登陆报错:

    ssh_exchange_identification: read: Connection reset by peer。
    

    2.问题原因

    最近安装MySQL数据库,
    安装过程中修改了var目录的权限,
    偷懒直接chmod -R 777 /var。

    3.解决办法

    将SSH相关文件的权限改回来,
    确保权限为755,属主为root:root。

    3.1.查看sshd状态

    service sshd status

    Redirecting to /bin/systemctl status sshd.service
    ● sshd.service - OpenSSH server daemon
       Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
       Active: active (running) since 二 2019-04-09 23:36:09 CST; 18h ago
         Docs: man:sshd(8)
               man:sshd_config(5)
      Process: 1357 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCESS)
     Main PID: 1358 (sshd)
       CGroup: /system.slice/sshd.service
               ├─ 1358 /usr/sbin/sshd
               ├─20443 sshd: root@pts/1
               ├─20445 sshd: root@notty
               ├─20447 /usr/libexec/openssh/sftp-server
               ├─20594 -bash
               ├─23794 sshd: mysql [priv]
               ├─23796 sshd: mysql@pts/0
               ├─23797 sshd: mysql [priv]
               ├─23799 sshd: mysql@notty
               ├─23800 /usr/libexec/openssh/sftp-server
               ├─23991 -bash
               ├─25381 vim /etc/init.d/mysqld
               └─25739 /bin/systemctl status sshd.service
    
    4月 10 17:59:47 dap229-156 sshd[21516]: pam_unix(sshd:session): session closed for user mysql
    4月 10 18:00:05 dap229-156 sshd[23794]: Accepted password for mysql from 10.43.163.30 port 54797 ssh2
    4月 10 18:00:05 dap229-156 sshd[23794]: pam_unix(sshd:session): session opened for user mysql by (uid=0)
    4月 10 18:00:05 dap229-156 sshd[23797]: Accepted password for mysql from 10.43.163.30 port 54798 ssh2
    4月 10 18:00:05 dap229-156 sshd[23797]: pam_unix(sshd:session): session opened for user mysql by (uid=0)
    4月 10 18:26:00 dap229-156 sshd[25579]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
    4月 10 18:26:12 dap229-156 sshd[25580]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
    4月 10 18:26:29 dap229-156 sshd[25581]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
    4月 10 18:26:46 dap229-156 sshd[25590]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
    4月 10 18:30:11 dap229-156 sshd[25622]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
    

    可以看到报错信息,
    提示/var/empty/sshd必须属于root用户,
    且所有其他用户都不能有写权限,
    所以文件权限可以改为755。

    3.2.修复文件权限

    chmod 755 /var/empty/sshd
    如果属主不对,还需要修改属主:
    chown root:root /var/empty/sshd

    3.3.重启sshd服务

    service sshd restart

    3.4.再次查看sshd状态

    service sshd status

    Redirecting to /bin/systemctl status sshd.service
    ● sshd.service - OpenSSH server daemon
       Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
       Active: active (running) since 三 2019-04-10 18:35:01 CST; 3s ago
         Docs: man:sshd(8)
               man:sshd_config(5)
      Process: 25768 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCESS)
     Main PID: 25769 (sshd)
       CGroup: /system.slice/sshd.service
               ├─20443 sshd: root@pts/1
               ├─20445 sshd: root@notty
               ├─20447 /usr/libexec/openssh/sftp-server
               ├─20594 -bash
               ├─23794 sshd: mysql [priv]
               ├─23796 sshd: mysql@pts/0
               ├─23797 sshd: mysql [priv]
               ├─23799 sshd: mysql@notty
               ├─23800 /usr/libexec/openssh/sftp-server
               ├─23991 -bash
               ├─25381 vim /etc/init.d/mysqld
               ├─25769 /usr/sbin/sshd
               └─25770 /bin/systemctl status sshd.service
    
    4月 10 18:35:01 dap229-156 systemd[1]: Starting OpenSSH server daemon...
    4月 10 18:35:01 dap229-156 systemd[1]: PID file /var/run/sshd.pid not readable (yet?) after start.
    4月 10 18:35:01 dap229-156 sshd[25769]: Server listening on 0.0.0.0 port 22.
    4月 10 18:35:01 dap229-156 sshd[25769]: Server listening on :: port 22.
    4月 10 18:35:01 dap229-156 systemd[1]: Started OpenSSH server daemon.
    

    这个时候检查没有错误了,
    服务器可以SSH登录了,
    至此问题解决。

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