centos升级openssl方法及步骤

1.下载要升级到的openssl包
https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-7.4p1.tar.gz

2.升级openssh前开通telnet
1)查看telnet包
rpm -qa|grep telnet
--如未安装，则yum安装
# yum install telnet
# yum install telnet-server

2)启动telnet
--编辑telnet文件,将disable改成no
# vi /etc/xinetd.d/telnet
# default: on
# description: The telnet server serves telnet sessions; it uses \
# unencrypted username/password pairs for authentication.
service telnet
{
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
disable = no
}

--重启xinetd服务
service xinetd restart
or
/etc/rc.d/init.d/xinetd restart

--通过telnet连接服务器

c:\> telnet 192.168.5.5
--默认telnet只能连接普通用户,然后,跳转到root用户

3.备份原openssh相关文件
# cp /usr/sbin/sshd /usr/sbin/sshd.bak
# cp /etc/ssh/ssh_config /etc/ssh/ssh_config.bak
# cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak
# cp /etc/ssh/moduli /etc/ssh/moduli.bak
--删除掉下面三个文件,否则安装的时候会报错.
rm -rf /etc/ssh/ssh_config
rm -rf /etc/ssh/sshd_config
rm -rf /etc/ssh/moduli
--安装编译所需包
yum install gcc
yum install pam-devel
yum install zlib-devel
yum install openssl-devel

4.解压并安装新版本openssh
# tar -zxvf openssh-7.4p1.tar.gz
# cd openssh-7.4p1
#./configure --prefix=/usr/local/openssh --sysconfdir=/etc/ssh --with-pam --with-md5-passwords --mandir=/usr/share/man
--configure报错终止,重新编译前先清理之前的编译信息.
# make clean
# ldconfig
# ./configure --prefix=/usr/local/openssh --sysconfdir=/etc/ssh --with-pam --with-md5-passwords --mandir=/usr/share/man
# make && make install

# /etc/init.d/sshd restart

5.覆盖旧的文件
# cp -p /softs/openssh-7.4p1/contrib/redhat/sshd.init /etc/init.d/sshd
# hmod u+x /etc/init.d/sshd
# chkconfig --add sshd
# cp /usr/local/openssh/sbin/sshd /usr/sbin/sshd

# cp /usr/local/openssh/sbin/sshd /usr/sbin/sshd
cp: overwrite `/usr/sbin/sshd'? y
cp: cannot create regular file `/usr/sbin/sshd': Text file busy
文件正在被使用
# ps -ef|grep sshd

# kill -9 77777
# ps -ef|grep sshd

--重新覆盖：
# cp /usr/local/openssh/bin/ssh /usr/bin/ssh
# service sshd restart

Stopping sshd: [ OK ]
ssh-keygen: illegal option -- A
usage: ssh-keygen [options]
Options:
...

# cat /etc/init.d/sshd
start()
{
# Create keys if necessary
/usr/bin/ssh-keygen -A
if [ -x /sbin/restorecon ]; then
/sbin/restorecon /etc/ssh/ssh_host_key.pub
/sbin/restorecon /etc/ssh/ssh_host_rsa_key.pub
/sbin/restorecon /etc/ssh/ssh_host_dsa_key.pub
/sbin/restorecon /etc/ssh/ssh_host_ecdsa_key.pub
fi

echo -n $"Starting $prog:"
$SSHD $OPTIONS && success || failure
RETVAL=$?
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/sshd
echo
}
--因低版本的ssh-keygen没有-A参数,因此，如下解决。
# cp /usr/local/openssh/bin/ssh-keygen /usr/bin/ssh-keygen

--重启sshd服务：
# service sshd restart

# vi /etc/ssh/sshd_config

--去掉如下条目注释,允许root通过ssh登录
PermitRootLogin yes

--注释掉下面三个参数
#GSSAPIAuthentication yes
#GSSAPICleanupCredentials yes
#UsePAM yes

6.重启sshd服务,并通过ssh连接服务器
# service sshd restart
c:\> ssh 192.168.5.5

# ssh -V

7.禁用telnet
# vi /etc/xinetd.d/telnet

# default: on
# description: The telnet server serves telnet sessions; it uses \
# unencrypted username/password pairs for authentication.
service telnet
{
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
disable = yes
}

--停止xinetd服务
# service xinetd stop
# chkconfig --list xinetd
# chkconfig xinetd off
# chkconfig --list xinetd

--如winscp登录linux报错,可如下解决
# vi /etc/ssh/sshd_config
--注释掉如下条目
#Subsystem sftp /usr/libexec/openssh/sftp-server
--添加如下条目
Subsystem sftp internal-sftp

--重启sshd服务：
# service sshd restart