The problem
When you detach a GNU Screen
session version 4.99 (C-a d), the only way to re-attach the
session (screen -r <session>) is by unlocking the session
using a password. There are situations where you don't like to be
forced to use passwords e.g. in a passwordless intranet or test
environment.
My issue with current GNU screen versions shipped with most
linux distributions
I had to use the most recent screen version from github due to the
fact that this was the only way that bashtop was
displayed properly within a screen session. A rotating monitoring
script that I wrote autonomously switches between 4 detached
screen sessions in a 5 sec (re-attaching) interval. After
investigating a while, I couldn't figure out a way using the docs
to disable GNU screen's password prompt when re-attaching a
detached session. My rotation script's intention was spoiled with
this screen 'force password' feature so I decided to take action
against it to workaround my issue.
The issue with latest GNU Screen 4.99
From ChatGPT I learnt, that in GNU Screen
4.99, the ability to disable passwords was removed, and there is
no straightforward configuration option to achieve this. Password
authentication is now enforced by default in GNU Screen 4.99 and
later versions. If you require a passwordless screen session, one
possible workaround is to downgrade to an earlier version of GNU
Screen that still supports disabling passwords. However, keep in
mind that downgrading software versions may have other
implications and could introduce potential security
vulnerabilities. Alternatively, you may consider exploring
alternative terminal multiplexer options that provide passwordless
session management, such as tmux.
Installation
mkdir /tmp/screen.d && cd /tmp/screen.d
wget https://marcgloor.github.io/data/screen-git-nopasswd-patch.tar.gz
tar xzf screen-git-nopasswd-patch.tar.gz
git clone https://git.savannah.gnu.org/git/screen.git
cd screen/src
zcat
../../screen-git-nopasswd-patch/screen-git-nopassword.patch.gz |
patch -p1 (file to patch: socket.c)
./autogen.sh
./configure
make
make install
eventually create a symlink: ln -s
/usr/local/bin/screen /bin/screenNote
Not sure ChatGPT's proplem analysis was trustworthy. For me,
it was the only root-cause I could determine and foundation to the
problem resolution of my issue. This page provides you with an
unofficial GNU
Screen
patch that removes the forced password feature when
re-attaching sessions. Note, that the password functionality in
GNU screen should be generally available, so that screen
sessions can be locked when away from the screen for a while.
Entirely killing this security feature is not the correct
way to handle this. My patch is a temporary workaround. I
initially contacted the maintainers/developers on 24th of May 2023
about this and opened a bug report
#64254 in order to verify that this is intended behaviour. Update follows.
$Id: gnuscreenpatch.html,v 1.8 2023/05/26 02:11:48 gloor Exp $ |