Centos Openssh升级为Openssh8.8最新版

最近因为做等保扫描出老版本的Openssh有漏洞，因此准备决心把Openssh升级到最新版本，前前后后折腾了两三个星期，中间填上了各种坑，最终终于搞定，最终版本为Openssh8.8p1 ,Openssl1.1.1l ,zlib-1.2.11

1.事前准备好三个安装包，大家可以去各大镜像源网站进行下载，如下所示

 

2、使用yum 对 gcc lrzsz 进行安装

[root@localhost ~]# mkdir upload
[root@localhost ~]# cd upload
[root@localhost upload]# rz                        //使用rz命令将包上传到upload文件夹中

所有的工作都已经准备就绪，以下马上就开始安装，大部分命令只需要复制粘贴即可，只需记住顺序千万不要搞错

1、解压包

cd
cd upload
tar -xvf openssl-1.1.1l.tar.gz
tar -xvf openssh-8.8p1.tar.gz
tar -xvf zlib-1.2.11.tar.gz

2、编译安装zlib

cd zlib-1.2.11
./configure --prefix=/usr/local/zlib
make && make install

3、编译安装openssl

cd ..
cd openssl-1.1.1l
./config --prefix=/usr/local/ssl -d shared
make && make install
echo '/usr/local/ssl/lib' >> /etc/ld.so.conf
ldconfig -v 

4、安装openssh

cd ..
cd openssh-8.8p1
./configure --prefix=/usr/local/openssh --with-zlib=/usr/local/zlib --with-ssl-dir=/usr/local/ssl
make && make install

5、sshd_config 文件修改

echo 'PermitRootLogin yes' >>/usr/local/openssh/etc/sshd_config
echo 'PubkeyAuthentication yes' >>/usr/local/openssh/etc/sshd_config
echo 'PasswordAuthentication yes' >>/usr/local/openssh/etc/sshd_config 

6、替换/etc/ssh里的文件

mv /usr/sbin/sshd /usr/sbin/sshd.bak
 cp  /usr/local/openssh/sbin/sshd /usr/sbin/sshd

mv /usr/bin/ssh /usr/bin/ssh.bak
 cp  /usr/local/openssh/bin/ssh /usr/bin/ssh

mv /usr/bin/ssh-keygen /usr/bin/ssh-keygen.bak
 cp  /usr/local/openssh/bin/ssh-keygen /usr/bin/ssh-keygen

mv /etc/ssh/ssh_host_ecdsa_key.pub /etc/ssh/ssh_host_ecdsa_key.pub.bak
cp /usr/local/openssh/etc/ssh_host_ecdsa_key.pub /etc/ssh/ssh_host_ecdsa_key.pub

mv /etc/ssh/ssh_host_dsa_key.pub /etc/ssh/ssh_host_dsa_key.pub.bak
cp /usr/local/openssh/etc/ssh_host_dsa_key.pub /etc/ssh/ssh_host_dsa_key.pub

7、更换openssl文件 这一步操作完成后 输入openssl version会发现openssl版本已经发生变化

mv /usr/bin/openssl /usr/bin/openssl_bak
cp /usr/local/ssl/bin/openssl /usr/bin/openssl

mv /usr/include/openssl /usr/include/openssl_bak
 ln -s /usr/local/ssl/include/openssl /usr/include/openssl

echo "/usr/local/ssl/lib" >> /etc/ld.so.conf
/sbin/ldconfig

8、替换启动文件

cd
cd  upload/openssh-8.8p1/
cp -a contrib/redhat/sshd.init /etc/init.d/sshd
 cp -a contrib/redhat/sshd.pam /etc/pam.d/sshd.pam
chmod +x /etc/init.d/sshd
chkconfig --add  sshd
systemctl enable sshd

9.sshd.service 会跟etc/init.d/sshd 文件形成冲突，而sshd.socket重启之后会发生报错所以进行移除

mv  /usr/lib/systemd/system/sshd.service   /usr/lib/systemd/system/sshd.service_bak
mv  /usr/lib/systemd/system/sshd.socket   /usr/lib/systemd/system/sshd.socket_bak

10.添加ssh开机启动

chkconfig sshd on
/etc/init.d/sshd restart

11.重新生成rsa dsa key （这一步是因为怕本地证书不符，所以加上的，可以不进行操作，请自测）

ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key
ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key

12. ssh  -V   进行测试

[root@localhost ~]# ssh -V
OpenSSH_8.8p1, OpenSSL 1.1.1l  24 Aug 2021
[root@localhost ~]# openssl version
OpenSSL 1.1.1l  24 Aug 2021
 

遇到的问题：（真是坑死我了）

1、KexAlgorithms 加密算法不支持报错， 先看一下报错信息

cat /var/log/message 

 Nov  4 16:03:20 localhost sshd[15961]: Unable to negotiate with 192.100.0.112 port 50581: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1 [preauth]

解释一下报错原因在openssh升级之后，默认不支持这四种加密算法，需要在本地sshd_config添加这四种算法，如果是按照我这种方法安装的只需下面这一条命令即可：

echo 'KexAlgorithms diffie-hellman-group1-sha1,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1' >>/usr/local/openssh/etc/sshd_config 

因为现在sshd 调用的配置文件在/usr/local/openssh/etc/sshd_config  而不是在/etc/ssh/sshd_config 最后再用sshd -T | grep kex验证一下，完美解决。

[root@localhost ~]# sshd -T | grep kex
kexalgorithms diffie-hellman-group1-sha1,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1

2、没有匹配的host key found 先看一下报错信息

Nov  4 16:26:11 localhost sshd[16438]: Unable to negotiate with 192.100.0.112 port 50725: no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth]

这个很简，单确认好sshd调用的配置文件后 

echo 'HostKeyAlgorithms +ssh-rsa,ssh-dss' >>/usr/local/openssh/etc/sshd_config

只需一条命令可以完全解决

3、出现create slice 死循环问题 先看日志

Jul 24 08:50:01 example.com systemd: Created slice user-0.slice.
Jul 24 08:50:01 example.com systemd: Starting Session 150 of user root.
Jul 24 08:50:01 example.com systemd: Started Session 150 of user root.
Jul 24 09:00:01 example.com systemd: Created slice user-0.slice.
Jul 24 09:00:02 example.com systemd: Starting Session 151 of user root.
Jul 24 09:00:02 example.com systemd: Started Session 151 of user root.

解决方法过滤掉相关的日志报警

echo 'if $programname == "systemd" and ($msg contains "Starting Session" or $msg contains "Started Session"
or $msg contains "Created slice" or $msg contains "Starting user-" or $msg contains "Starting User Slice
of" or $msg contains "Removed session" or $msg contains "Removed slice User Slice of" or $msg contains
"Stopping User Slice of") then stop' >/etc/rsyslog.d/ignore-systemd-session-slice.conf

以上就是Openssh升级的所有过程，以及遇到的所有的坑，欢迎留言指导