Installing Qt 5.5.1 on Ubuntu 14.04 - throws qt.network.ssl error on terminal

Question

I am planning to install qt 5.5.1 on my ubuntu 14.04 running on virtual machine. I have downloaded the installer from qt-io and when I try to install the setup, I notice the below warning on my terminal, and then the installer pop up.

qt.network.ssl: QSslSocket: cannot resolve SSLv2_client_method
qt.network.ssl: QSslSocket: cannot resolve SSLv2_server_method

Do I need to worry much about this warning ? I dont see any error of this kind when I installed qt 5.3.1 on same machine.

Is there a way to resolve this warning ? Any help is appreciated. Thanks.

This is the current version of openSSL on my machine.

openssl version -v
OpenSSL 1.0.1f 6 Jan 2014

Solution

Now OpenSSL in Ubuntu is compiled without sslv2 because it’s insecure, but Qt 5.5.x still requires it. In order to enable sslv2 the package needs to be re-configued without the no-sslv2 flag.

Install the prerequisite packages

sudo apt-get update
sudo apt-get install libssl-dev devscripts dpkg-dev cdbs debhelper dh-autoreconf libev-dev libpcre3-dev pkg-config

And then, grab the source

cd ~/Downloads
sudo apt-get update
apt-get source openssl

Now we need to edit the file in openssl-1.0.1f/debian/rules. Find the line 44 (maybe the line number will be different in various version) and remove no-ssl2 so that it will be like below:

cd openssl-1.0.1f
nano debian/rules
CONFARGS  = --prefix=/usr --openssldir=/usr/lib/ssl --libdir=lib/$(DEB_HOST_MULTIARCH) no-idea no-mdc2 no-rc5 no-zlib  enable-tlsext no-ssl3 enable-unit-test $(ARCH_CONFARGS)

Next we will add a comment and commit the change. Then re-build the package, this is going to take some time so skip down to the nmap part and download the source. You might get some error says copyright was unable to be verified, ignore it. Moreover, the compiling might take a while so be patient.

dch –n 'Allow SSLv2'
dpkg-source --commit
debuild -uc -us

Now back to ~/Downloads you will see all the deb packages built. Install them:

cd ..
sudo dpkg -i *ssl*.deb

Now redo your Qt 5.5.1 installation to see if the warnings persist.

Comments

[Tung Tran]

@user12345: Does it work?

[user12345]

I am pretty new to linux, and so am taking some time to figure out. When I did the first step, I see an error like this: user@ubuntu:~/Downloads$ apt-get source openssl Reading package lists... Done Building dependency tree Reading state information... Done E: You must put some 'source' URIs in your sources.list

[Tung Tran]

I've edited my answer. Please launch sudo apt-get update before apt-get source openssl

[user12345]

Actually, I had an issue with sudo apt-get update. So i have this another thread running to find the answer for it. And you are the one helping me there as well. askubuntu.com/questions/711889/…

[Tung Tran]

Well, I didn't notice that. Ok at first you have try to overcome your proxy issue.

[Tung Tran]

So your proxy is resolved. Try the solution to deal with one.

[user12345]

My CONFARGS is like this in the file: CONFARGS = --prefix=/usr --openssldir=/usr/lib/ssl --libdir=lib/$(DEB_HOST_MULTIARCH) no-idea no-mdc2 no-rc5 no-zlib enable-tlsext no-ssl2 $(ARCH_CONFARGS) If I just remove no-ssl2 : it will look like this CONFARGS = --prefix=/usr --openssldir=/usr/lib/ssl --libdir=lib/$(DEB_HOST_MULTIARCH) no-idea no-mdc2 no-rc5 no-zlib enable-tlsext $(ARCH_CONFARGS) Is that fine! or shall I copy the contents from your answer for CONFARGS as is ? The difference was just extra no-ssl3 enable-unit-test in your answer

[Tung Tran]

Yours is fine. Just keep it like that. Mine is the other version thus it's a bit different.

[user12345]

When I did commit changes: I see the below message, is that fine ? dpkg-source: info: using options from openssl-1.0.1f/debian/source/options: --extend-diff-ignore=(^|/)(Makefile)$ dpkg-source: info: there are no local changes to record

[Tung Tran]

Notice that the build will take >5 mins.

[user12345]

I have one more question though, which is not relevant to this issue. I have started upgrading my machine to Ubuntu 14.04 LTS from Ubuntu 12.04, thinking that this version of Ubuntu should have support and maintanence updates for atleast 2 years. Am I correct ?

[Tung Tran]

New LTS version is released every 2 years. In previous releases, a Long Term Support (LTS) version had 3 years support on Ubuntu (Desktop) and 5 years on Ubuntu Server. Starting with Ubuntu 12.04 LTS, both versions will receive 5 years support. Ubuntu 12.04 will be supported until 10/2017 and Ubuntu 14.04 till 10/2019.

[Lennart Rolland]

wow dude! Now I know how to do deb! Most awesome post evar tx.