gdebi-gtk calls pkexec inappropriately

[Lantizia]

Steps to reproduce:

1. Have Ubuntu with gdebi-gtk installed
2. Open Firefox
3. Visit some site with deb-package download link or use direct link like https://github.com/jgm/pandoc/releases/download/2.9.2.1/pandoc-2.9.2.1-1-amd64.deb
4. Proceed with file downloading
5. In Firefox select Library → Downloads, click on downloaded deb-file

Expected results:
* gdebi-gtk is opened, the package installs normally after users clicks Install button

Actual results:
* gdebi-gtk is opened, the package is not installed because of vanishing of gdebi-gtk window just after clicking Install button

----

Before anyone says this bug already exists... it doesn't (at least as far as I can see). It's just that a lot of similar bugs do/did exist where people have also experienced the same symptoms (of gdebi-gtk vanishing upon clicking 'Install').

So yes this is the same symptoms, but it must be a different cause as the circumstances are different and doesn't have the same resolution.

The meat of it...

Basically on a fresh install of Ubuntu MATE 18.04.3 amd64... with Firefox (or with Chrome if you installed that) go to any site that offers a .deb package and either...
a) choose to open it directly from the browser (rather than saving it to 'Downloads' folder)
b) or... save the file (e.g. to the 'Downloads' folder), BUT!.. open that file from within the browser itself.

You should find that gdebi-gtk appears but vanishes the moment you click 'Install' without a prompt for a password, an explanation or the package actually getting installed.

This bug has existed since the beginning of Ubuntu 18.04 however it's been largely confused with other similar bugs. I've had it on half a dozen machines and confirmed it exists with IRC users on #ubuntu-mate of freenode.

However with *this* bug (compared to others) gdebi-gtk works perfectly fine if you run it from the terminal or just double click the .deb package from your file manager.

It's the kind of bug which if you're a hardened desktop Linux user, you'd just work around it...

But if you're a novice and you can't get a simple thing like Teamviewer installed (which is a .deb, and a thing I might ask someone to do over the phone to try to help them) you likely get fed up and re-install Windows :S

Any input on this would be brilliant as I can't seem to get any logs/output.

~lantizia

[Lantizia (lantizia)]

So a workaround for anyone reading this... (thanks to alkisg on freenode for working with me on this)...

sudo rm /usr/bin/gdebi-gtk
echo '#!/bin/sh' | sudo tee /usr/bin/gdebi-gtk
echo '/usr/share/gdebi/gdebi-gtk "$@"' | sudo tee -a /usr/bin/gdebi-gtk
sudo chmod +x /usr/bin/gdebi-gtk

Don't worry deleting 'gdebi-gtk' on that first line, it's only a symlink.

Basically this wrapper is needed otherwise policy kit complains and states "Refusing to render service to dead parents."

[Lantizia (lantizia)]

Goes back further than Ubuntu 18.04 then...

https://stackoverflow.com/questions/49214954/gdebi-refusing-to-render-service-to-dead-parents

[Alkis Georgopoulos (alkisg)]

The following workaround doesn't remove anything and allows the wrapper to survive updates:

sudo -i
printf '#!/bin/sh\n\n/usr/share/gdebi/gdebi-gtk "$@"\n' > /usr/local/bin/gdebi-gtk
chmod +x /usr/local/bin/gdebi-gtk
exit

[Elliot (cheese-e-boi)]

No issue on Ubuntu MATE 19.10! This was tested with Firefox 70.0.1 and the Minecraft deb package.

[Nicholas Harvey (mobile-harvey)]

Still seeing this issue on 19.10 with Firefox and 20.04 also.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Norbert (nrbrtx)]

Still happens on Focal final. Do not have any clues how to debug this.

[Alkis Georgopoulos (alkisg)]

The problem is not in firefox or mate, it's in gdebi-gtk, and specifically in GDebiGtk.py, line 619:

os.execv(pkexec_cmd, pkexec_args+gdebi_args)

This replaces the current process with a pkexec call. This is not a valid usage of pkexec, as pkexec requires the parent process to not be init (ppid!=1).

To reproduce the issue without firefox, one can just run `setsid gdebi-gtk package.deb`.

In a similar bug report for update-manager (LP: #1020115), this flag was used instead of os.execv:

flags = GObject.SPAWN_DO_NOT_REAP_CHILD
https://bazaar.launchpad.net/~ubuntu-core-dev/update-manager/main/view/head:/UpdateManager/backend/InstallBackendSynaptic.py#L63

Is gdebi still maintained by Ubuntu developers, or should we report this in Debian?
Can we propose a patch similar to the update manager, or even just use a simple shell wrapper?

[Marcel Partap (empee584)]

Thanks for the workarounds! Fantastic that progress is picking up, it seemed doubtful this would ever be resolved. ⏳😅

[Norbert (nrbrtx)]

Still happens on Bionic. Need official fix.

[Sai Vinoba (saivinob)]

Can somebody please re-check and confirm on focal? On UM focal I'm not seeing this issue but do so on hirsute and impish.

When we click on a .deb file firefox asks 'What should Firefox do with this file?, with `open with` and `save` being two options. I tried the following one by one.
  a) Chose open with. Install with gdebi was OK.
  b) Chose save. But opened downloaded file from within firefox (from download icon on navigation bar). OK.
  c) Chose save but then opened downloaded file from Caja. OK.

On hirsute and impish only c) works. a) and b) fail.

Gdebi version on focal: 0.9.5.7+nmu3

[Norbert (nrbrtx)]

I'm seeing the same buggy behavior on freshly installed Ubuntu MATE 20.04.2 LTS running inside VirtualBox.

[Norbert (nrbrtx)]

21.04 is still affected.

[Norbert (nrbrtx)]

21.10 is confirmed as affected.

[Patrick Fasano (kc9jud)]

I recently noticed that this is no longer occurring on Ubuntu MATE 20.04.3. I am uncertain when it was fixed.

[Lantizia (lantizia)]

@Patrick Fasano (kc9jud)

I've just made a new blank VM, downloaded a fresh copy of the Ubuntu MATE 20.04.3 amd64 ISO... and installed it (the only choices I made of note were.. picking a Minimal install with 3rd party firmware/codecs/etc..)

I can not confirm your findings.

I tried going to these sites to download their 64-bit .deb packages (follow the most obvious links to download on each site)...
- nomachine.com
- teamviewer.com
- skype.com

And found that whether you...
a) allow Firefox to save to disk and afterwards open the .deb from within Firefox (either from the Downloads button on the toolbar, or within the Library window of Firefox)... or...
b) ask Firefox to 'Open with' the 'GDebi Package Installer (default)' upon it finishing the download...

You get the same issue where GDebi opens but the 'Install Package' button makes GDebi instantly close.

However (just as before), if you go to your Downloads folder in an actual file manager (outside of a web browser like Firefox or Chrome) and open the .deb... then the 'Install Package' button functions normally.

Nothing has really changed with this bug at all... I'm pretty sure I first noticed this way back in 14.04 (so this bug is now over 6 years old in reality) and it's one of the worse experiences a first time user of Linux could have.

Especially when you consider most have come from a world where a .exe or a .dmg (when downloaded)... "Just works".

[Norbert (nrbrtx)]

Bug still exists in 22.04.

[Doug Brown (macg3)]

I have no idea what I'm doing here in terms of submission processes, but I attempted to submit a patch for this issue:

https://code.launchpad.net/~macg3/ubuntu/+source/gdebi/+git/gdebi/+merge/414211

I suspect I may have done something wrong in the submission process because "git-ubuntu import" is listed as the code reviewer. It was really confusing because there was also a bzr project for this package that is outdated, and it appears it has been moved to Git. Anyway, this patch fixes the issue by adding a separate python script that acts as the parent process for pkexec. Special thanks to Alkis Georgopoulos for all of the info provided above.

[Robie Basak (racb)]

I've linked the MP and subscribed ~ubuntu-sponsors.