How to install openssh from centos 7 source code

Environment: centos 7.1.1503 minimal installation

Dependent package download: yum -y install lrzsz zlib-devel perl gcc pam-devel

1、 Install openssl, choose the latest version: openssl-1.1.1g.tar.gz

1 ) Openssl download address: https://www.openssl.org/source/openssl-1.1.1g.tar.gz

2 ) Uninstall the openssl pre-installed in the system, this step can be omitted

rpm -qa | grep openssl | grep -v lib

yum -y remove openssl-1.0.1e-42.el7.x86_64

3 )installation steps:

tar -zxvfopenssl-1.1.1g.tar.gz

cdcd openssl-1.1.1g

. /config –prefix=/usr/local/openssl –openssldir=/usr/local/openssl -Wl,-rpath,/usr/local/openssl/lib shared

make && make install

4 ) Create a soft link

ln -s /usr/local/openssl/bin/openssl /usr/bin/openssl

ln -s /usr/local/openssl/include/openssl /usr/include/openssl

5 ) Update system configuration

echo “/usr/local/openssl/lib” >> /etc/ld.so.conf

/sbin/ldconfig

6 ) Check version

openssl version

2、 Install openssh, choose the latest version: openssh-8.3p1.tar.gz

1 ) Openssh download address: https://openbsd.hk/pub/OpenBSD/OpenSSH/portable/openssh-8.3p1.tar.gz

2 ) Back up the openssh configuration file of the system

cp -r /etc/sysconfig/sshd /etc/sysconfig/sshd.bak

cp -r /sys/fs/cgroup/systemd/system.slice/sshd.service /sys/fs/cgroup/systemd/system.slice/sshd.service.bak

cp -r /usr/lib/systemd/system/sshd.service /usr/lib/systemd/system/sshd.service.bak

cp -r /usr/lib/systemd/system/sshd.socket /usr/lib/systemd/system/sshd.socket.bak

cp -r /usr/lib/systemd/system/[email protected] /usr/lib/systemd/system/[email protected]

cp -r /usr/lib/systemd/system/sshd-keygen.service /usr/lib/systemd/system/sshd-keygen.service.bak

3 ) Uninstall the openssh pre-installed in the system, this step can be omitted

rpm -qa | grep openssh

yum -y remove openssh-server-6.6.1p1-11.el7.x86_64 openssh-clients-6.6.1p1-11.el7.x86_64 openssh-6.6.1p1-11.el7.x86_64

4 ) Back up the openssh configuration file, this step can be omitted

cp -r /etc/ssh /etc/ssh.bak

rm -rf /etc/ssh #This step is very important and must be done

5 )installation steps

tar -zxvf openssh-8.3p1.tar.gz

cd openssh-8.3p1

. /configure –prefix=/usr/local/openssh –sysconfdir=/etc/ssh –with-openssl-includes=/usr/local/openssl/include –with-ssl-dir=/usr/local/openssl –with-zlib –with-md5-passwords –with-pam –with-ssl-engine

make && make install

6 ) Create a soft link

ln -s /usr/local/openssh/sbin/sshd /sbin/sshd

ln -s /usr/local/openssh/bin/ssh /usr/bin/ssh

ln -s /usr/local/openssh/bin/ssh-add /usr/bin/ssh-add

ln -s /usr/local/openssh/bin/ssh-keygen /usr/bin/ssh-keygen

ln -s /usr/local/openssh/bin/ssh-keyscan /usr/bin/ssh-keyscan

7 ) Restore the backup configuration file

mv /etc/sysconfig/sshd.bak /etc/sysconfig/sshd

mv /sys/fs/cgroup/systemd/system.slice/sshd.service.bak /sys/fs/cgroup/systemd/system.slice/sshd.service

mv /usr/lib/systemd/system/sshd.service.bak /usr/lib/systemd/system/sshd.service

mv /usr/lib/systemd/system/sshd.socket.bak /usr/lib/systemd/system/sshd.socket

mv /usr/lib/systemd/system/[email protected] /usr/lib/systemd/system/[email protected]

mv /usr/lib/systemd/system/sshd-keygen.service.bak /usr/lib/systemd/system/sshd-keygen.service

8 ) Check the openssh version

ssh -V

9 ) Modify the openssh configuration file to allow root login

vi /etc/ssh/sshd_config

Change #PermitRootLogin prohibit-password to PermitRootLogin yes

10 ) Set the sshd service to start on boot

chkconfig sshd on

11 ) Restart the sshd service

systemctl restart sshd && systemctl restart sshd && systemctl restart sshd && systemctl restart sshd &

At this point, the openssh service installation is complete, if you are not assured, you can reboot to restart the machine

ps: Let’s see how to solve the problem of compiling and installing openssl under Linux without generating dynamic link library .so

Using the official config command, the .so is not generated by default. The solution is to add the parameter shared when executing ./config, for example:

. /config –prefix=/usr/local/ssl –openssldir=/usr/local/ssl -Wl,-rpath,/usr/local/ssl/lib shared

Then make && make install