1、准备：
    安装必须的包：yum install zlib zlib-devel openssl-devel pam-devel pam-krb5 krb5-devel   krb5-libs pam-devel
    下载：wget https://mirror.esc7.net/pub/OpenBSD/OpenSSH/portable/openssh-7.5p1.tar.gz
    
2、安装：
    tar zxf openssh-7.5p1.tar.gz
    cd openssh-7.5p1
          ./configure --prefix=/usr --sysconfdir=/etc/ssh --with-pam --with-zlib --with-ssl-dir=/usr --with-md5-passwords --mandir=/usr/share/man --with-kerberos5=/usr/lib64/libkrb5.so（防止出现Unsupported option GSSAPIAuthentication  和 Unsupported option GSSAPICleanupCredentials）
    会出现以下提示：

    PAM is enabled. You may need to install a PAM control file for sshd, otherwise password authentication may fail.Example PAM control files can be found in the contrib/ subdirectory
  
    cp /etc/init.d/sshd /etc/init.d/sshd_old
    cp /etc/pam.d/sshd /etc/pam.d/sshd_old
    cd openssh-7.5p1/contrib/redhat
    cp sshd.init /etc/init.d/sshd
    cp sshd.pam /etc/pam.d/sshd
    修改/etc/ssh/sshd_config中 UsePAM yes
    
    make && make install
3、重启sshd服务

    service sshd restart
    ssh -V

4、注：ssh升级后，默认关闭root远程登录，如果需要，请打开

5、如果无法登录，请修改/etc/pam.d/sshd
    auth       required     pam_sepermit.so
    auth       include      password-auth
    account    required     pam_nologin.so
    account    include      password-auth
    password   include      password-auth
    # pam_selinux.so close should be the first session rule
    session    required     pam_selinux.so close
    session    required     pam_loginuid.so
    # pam_selinux.so open should only be followed by sessions to be executed in the user context
    session    required     pam_selinux.so open env_params
    session    required     pam_namespace.so
    session    optional     pam_keyinit.so force revoke
    session    include      password-auth