Ubuntu – How to properly downgrade openssl version under Ubuntu 18.04

18.04aptdependenciesopenssl

I need to install some proprietary antivirus software on my 18.04 system because of company policy. The thing is, it requires an older version of OpenSSL to even install and then work, i.e. Ubuntu 18.04 uses 1.1 series, and the software depends on version 1.0. They don't seem to be planning to change that in the near future since Linux is not a priority platform for them.

Apt does not see any older versions than 1.1 in the repositories. I managed to find a .deb file with some 1.0.1 version, but obviously just installing it breaks dependencies throughout the whole system and apt wants me to run installation fix (which just installs the newest version).

Removing the currently installed OpenSSL version (to later install the old one) is out of the question since that also removes lots of important packages that I require for work (including the whole Gnome environment).

Is there a way to properly downgrade OpenSSL to 1.0 without breaking the system, or at least have both versions installed (and just direct the software and its installer to the older one)?

Best Answer

You can try the following:

sudo apt-get install -y --allow-downgrades openssl1.0=1.0.2n-1ubuntu5.1 
echo "export OPENSSL_DIR=/usr/lib/ssl1.0/" >> ~/.bashrc

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Ubuntu – Libssl Dependencies

Go to software centre and search for mintupdate and remove it. I had to do this twice as the first time failed.

I then installed it again and the problem was fixed.

Ubuntu – How to downgrade packages without removing their dependants

I never played with this before, but I would suggest that you hold (or lock) the version of the dependencies that cause you trouble. This way apt has a more limited number of possible solutions, and perhaps doesn't get confused when you attempt to downgrade the other packages.

If nothing else works, you could take the manual approach suggested in this answer: How to Downgrade a Package via apt-get?. Basically, download the necessary .deb packages manually, then install them one by one using the lower-level dpkg and one of its forceful arguments: --ignore-depends, --force-depends, --force-depends-version, or even --force-all.

In the same spirit as the above, you have the --force-downgrade argument:

          downgrade(*): Install a package, even if newer version of
          it is already installed.

          Warning:  At  present  dpkg  does  not  do any dependency
          checking on downgrades and therefore will not warn you if
          the  downgrade  breaks the dependency of some other pack‐
          age. This can  have  serious  side  effects,  downgrading
          essential system components can even make your whole sys‐
          tem unusable. Use with care.

But this assumes that you've read man dpkg, and that you understand what you do:

          Warning: These options are mostly intended to be used  by
          experts  only.  Using  them  without  fully understanding
          their effects may break your whole system.

See Error: version number does not start with digit and How to install an older version of Java and How to install a older version of package like liquid 2.2.2? for examples of:

sudo dpkg --force-downgrade -i your_mesa_package.deb

And see How can I install a package without installing some dependencies? for an example (along with the appropriate warning) of:

sudo dpkg --force-all -i your_mesa_package.deb

Yet another approach would be to create a dummy .deb package using the equivs package (and perhaps a slightly different name). Then installing the dummy package should allow you to remove the "true" package while keeping the relevant deps, and then install the older version. I'm not sure how exactly this would work, but check this relevant thread for details: How to remove a deb without removing its dependencies.

Best Answer

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Ubuntu – Libssl Dependencies

Ubuntu – How to downgrade packages without removing their dependants

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