When updating the packages on my Debian I get this error every now and then, and it’s really annoying:
W: GPG error: http://linux.dropbox.com/debian bookworm Release: The following signatures were invalid: BADSIG FC918B335044912E Dropbox Automatic Signing Key <linux@dropbox.com>
E: The repository 'http://linux.dropbox.com/debian bookworm Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
An internet search about the problem will throw a lot of different solutions at you. Some of them are quite heavy-handed. Some of them just don’t work. Most of them don’t really explain what you are doing when you run the commands you run. I checked a bunch of them and found my own solution.
My understanding of the problem is that packages lists from the Dropbox repository get corrupted for some reason, and this happens way more often with that repo than with any other I am using. When that happens, there may be something left in /var/lib/apt/partial, and it’s better to download the package information for that repository from scratch.
As root (e.g. after running sudo -s or sudo -i), run
find /var/lib/apt/lists -type f -name \*dropbox\* -print | xargs rm
This command will find all files (-type f) whose name contains the string “dropbox” (-name \*dropbox\*) under the directory /var/lib/apt/lists and its subdirectories, and then pass them as arguments to the rm command (xargs rm), hence deleting them.
When that is done, run apt update again and, hopefully, the error will be gone (well, unless the package information gets corrupted once again, that is…).
Debian 12 “bookworm” was officially released two days ago, yay!
And just like me, this morning your attempt to update the apt package cache may have been met by an odd notification similar to this one:
E: Repository 'http://deb.debian.org/debian testing InRelease' changed its 'Codename' value from 'bookworm' to 'trixie'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Why it’s happening
I have this source configured in apt:
deb-src http://deb.debian.org/debian/ testing main contrib non-free
The source refers to the distribution “testing”. The codename for testing is the same of the next Debian release. Before the release of Debian 12 it was “bookworm”. Now that bookworm is released, that codename switched to “trixie”. In my particular case, this is more or less harmless, as this source is not going to trigger the installation of any package. But if I was using “testing” or “stable” in my apt sources, that would make a difference: I may unintentionally install packages from Debian 12 on my Debian 11 and make a mess of my system.
The error and the notification are there to warn you that there was a codename change, and that you should consider if this is expected and you actually want to continue, or if you’d rather lock your sources to the current codename instead (that would be “bullseye” in Debian 11’s case).
What to do
Lock your package sources to the correct codename. E.g. if you are running Debian 11 and you have “stable” in your apt sources for the official Debian repositories, replace “stable” with “bullseye”. Note that for third party repos this may be different, check with the vendor for instructions.
If, like in my case, the change is harmful, you need to let apt know that you approve the change. That’s what we’ll see below in detail.
Accepting the codename change
The notification points to apt-secure. If you are like me, the next command you ran was man apt-secure. That helped finding more about the reason why this was happening, but not with the solution, alas:
INFORMATION CHANGES
A Release file contains beside the checksums for the files in
the repository also general information about the repository
like the origin, codename or version number of the release.
This information is shown in various places so a repository
owner should always ensure correctness. Further more user
configuration like apt_preferences(5) can depend and make use
of this information. Since version 1.5 the user must therefore
explicitly confirm changes to signal that the user is
sufficiently prepared e.g. for the new major release of the
distribution shipped in the repository (as e.g. indicated by
the codename).
This is nice. Except that it doesn’t mention how one is supposed to explicitly confirm changes.
Some more digging and the man page of apt-get provided the solution:
--allow-releaseinfo-change
Allow the update command to continue downloading data from
a repository which changed its information of the release
contained in the repository indicating e.g a new major
release. APT will fail at the update command for such
repositories until the change is confirmed to ensure the
user is prepared for the change. See also apt-secure(8) for
details on the concept and configuration.
Specialist options (--allow-releaseinfo-change-field) exist
to allow changes only for certain fields like origin,
label, codename, suite, version and defaultpin. See also
apt_preferences(5). Configuration Item:
Acquire::AllowReleaseInfoChange.
Running apt-get update –allow-releaseinfo-change returned the notification part again (the message prefixed with “N:“) but not the error (“E:“). Subsequent runs of apt/apt-get ran as usual. Problem solved 🙂
In my first article about the deprecation of apt-key I illustrated a few ways of adding APT repository keys to your system without using the apt-key command. A good follow-up discussion to that article started on twitter (thanks to Petru Ratiu). The topics we discussed were: the use of the signed-by clause and if it really helps increasing security; the use of package pinning to avoid third-party packages taking over official packages; and the pollution of system directories.
In this post we dig a bit deeper into these topics and how they help, or don’t help, making your system more secure. A TL;DR for the impatient is included at the end of each section.
It’s only a few weeks since I upgraded one of my systems from Debian 10 to Debian 11. In fact, I use to apply a “Debian distribution quarantine”: when a new major version of the distribution is out, I usually wait until a “.1” or “.2” minor version before installing it, as I don’t have enough time to debug problems that may have escaped Debian’s QA process at the very first release.
One of the first things that catch one’s attention when I ran the apt-key command in Debian 11 (e.g. a simple apt-key list) was a warning:
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8))
“Deprecated” usually means that a certain functionality will be eventually removed from the system. In this case, Ubuntu users will be hit already in 2022 with the release of 22.10 in October as the command will be available last in the next LTS (22.04) to be released in April. Debian users will have more time, as the command won’t available in the next major release of Debian (supposedly Debian 12, that may be a couple of years away). This is written in clear letters in the man page:
apt-key(8) will last be available in Debian 11 and Ubuntu 22.04.
So, what are you supposed to do now in order to manage the keys of third party APT repositories?
Package installation can be tricky sometimes when using configuration management tools, as the order in which package operations are performed can have an impact on the final result, sometimes a disastrous impact. Months ago I had been looking for a way to make apt-get a bit less proactive when trying to solve dependencies and removing packages and came up with the following package method that we now have in our library.
To use it, just put it in your policies and use apt_get_safe in your policies instead of apt_get wherever you want a more prudential approach to package installations.
I’m putting it here in the hope that it may be useful for everyone. I have used it successfully in Debian 5, 6, 7, 8 and on CFEngine 3.4.4 (where I borrowed parts of the masterfiles from 3.5 and 3.6 like, e.g., the debian_knowledge bundle) and 3.6.x. Enjoy!
A sysadmin's logbook 