[Bug 1908469] [NEW] Cannot install .deb packages opened from Firefox

[Launchpad Bug Tracker]

You have been subscribed to a public bug:

Suppose in Firefox you click a link to a .deb package. A dialog named
"Opening [filename].deb" opens. If you select "Open with", then the .deb
file is downloaded, placed in /tmp/mozilla_[username]0/ directory, then
Software Install (as named in the Firefox dialog) is started on that
.deb file.

Next, Software Install loads and fails with "Failed to install file: not
supported".

If on the other hand, in Firefox's "Opening [filename].deb" dialog, if I
select "Save File" instead, the .deb file ends up in the user's
Downloads directory. Software Install works fine with the package there.

I don't want to get too much into solutioning or "why". The main point
of this bug is that I should not get a weird error just because I
selected "Open with" instead of "Save File". This happens with a vanilla
install of Ubuntu, with nothing else installed, so the product isn't
working in an intuitive way.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity (not installed)
ProcVersionSignature: Ubuntu 5.8.0-33.36-generic 5.8.17
Uname: Linux 5.8.0-33-generic x86_64
ApportVersion: 2.20.11-0ubuntu50.3
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Wed Dec 16 19:54:01 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
InstallationDate: Installed on 2020-12-10 (6 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
Symptom: installer
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: ubiquity (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug groovy ubiquity-20.10.13
-- 
Cannot install .deb packages opened from Firefox
https://bugs.launchpad.net/bugs/1908469
You received this bug notification because you are a member of Ubuntu Foundations Bugs, which is subscribed to ubiquity in Ubuntu.