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Message #36966
[Bug 1895302] Re: groovy debootstrap leaves /e/d/motd-news.wasremoved around
** Description changed:
[Impact]
A fresh install of base-files, like done when using debootstrap, using the base-files from the -updates repository (in the case of ubuntu stable releases), will leave an empty /etc/default/motd-news.wasremoved file. This file is an artifact of the mechanism used to handle a corner case in the previous SRU where it would signal the motd-news-config package to install /etc/default/motd-news with ENABLED=0. See testcases (h) and (i) in the previous base-files SRU at https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575 for details. In test case (i) it was acked that the empty .wasremoved file was lying around, but its impact was deemed not relevant (see [other info] item (a)).
Another case where /etc/default/motd-news.wasremoved would be created
when it shouldn't be is when you have just base-files installed (and no
ubuntu-server or motd-news-config) and did a reinstall of base-files, or
an upgrade. It would again touch /etc/default/motd-news.wasremoved.
The consequence of having /etc/default/motd-news.wasremoved when it's
unintended is that a follow-up install of ubuntu-server, or motd-news-
config for that matter, will install /etc/default/motd-news with
ENABLED=0 instead of ENABLED=1.
This was the case of the groovy debootstrap which resulted in this bug
being filed. While debootstrap won't mix multiple repositories (like
release with updates), and thus this isn't easily a problem in released
versions of ubuntu, the groovy case was the one that was doing a fresh
install of base-files with the buggy touch /etc/default/motd-
news.wasremoved, and a subsequent install of ubuntu-server left motd-
news disabled in groovy images produced by such a method (debootstrap).
These are the scenarios I was able to come up with in which a stable
release could be affected by this bug:
a) debootstrap with release and updates pocket enabled
There are no config options that I'm aware of that would tell debootstrap to use multiple pockets when creating a chroot, but let's say it was done by hacking the script or something else. It would then be the same case as groovy until this fix: subsequent installations of ubuntu-server or motd-news-config would default to having motd-news disabled
b) A system that has just base-files from the previous SRU installed,
and no ubuntu-server and no motd-news-config. If base-files were updated
again and without the fix presented here (let's say, another SRU instead
of this one), it would create /etc/default/motd-news.wasremoved, and
again, a subsequent install of ubuntu-server or motd-news-config would
install motd-news in a disabled state
c) Any other case where the postinst script of base-files is run again
without the fix presented here, and when there is no /etc/default/motd-
news{,.dpkg*} file present.
To avoid creating /etc/default/motd-news.wasremoved when we shouldn't, the maintainer scripts were changed as follows:
- motd-news-config postinst: always remove the .wasremoved file in configure if found, regardless if /etc/default/motd-news was sed'ed or not, or if we are upgrading or on a first install
- base-files postinst: guard the creation of .wasremoved with:
- Only during an upgrade
- Only if ubuntu-server is installed (via a dpkg -l check)
[Test Case]
* On the system under test, remove motd-news-config and ubuntu-server if they are installed, and keep base-files from the update pocket. Something like this:
sudo apt update
sudo apt purge motd-news-config ubuntu-server
apt-cache policy base-files <-- to verify it's from updates
* In this scenario, you should have no /etc/default/motd* files:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
* reinstall base-files:
sudo apt install --reinstall base-files
* Before this SRU, this would create /etc/default/motd-news.wasremoved:
$ ll /etc/default/motd*
-rw-r--r-- 1 root root 0 Sep 16 20:24 /etc/default/motd-news.wasremoved
With the package from proposed for this SRU installed, no such file is created:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
+ [Regression Potential]
+ This SRU is further changing maintainer scripts, to address an issue in the previous maintainer script. Should there be new regressions or new issues, it might get harder and harder to fix them.
- [Regression Potential]
+ I did wonder about the `dpkg -l` call in base-files' postinst. I worried
+ about locks, or pre-dependencies, but dpkg was already being used in
+ this script, although not with -l (list), just a version comparison. But
+ at least it's already installed.
- * discussion of how regressions are most likely to manifest as a result
- of this change.
-
- * It is assumed that any SRU candidate patch is well-tested before
- upload and has a low overall risk of regression, but it's important
- to make the effort to think about what ''could'' happen in the
- event of a regression.
-
- * This both shows the SRU team that the risks have been considered,
- and provides guidance to testers in regression-testing the SRU.
+ My other worry was with the dpkg -l output and which flags I should
+ check to determine if ubuntu-server was installed. "^ii" doesn't work,
+ because ubuntu-server might be being upgraded in the same apt
+ transaction, but ^i seemed good enough. Furthermore, I changed the check
+ for a package name that doesn't exist, to see if dpkg -l would complain
+ and fail the whole script (which runs with set -e), but it was ok and
+ just behaved as if the package wasn't installed, which is what we need.
[Other Info]
* Anything else you think is useful to include
* Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board
* and address these questions in advance
[Original Description]
When debootstrapping groovy, we see an empty /etc/default/motd-
news.wasremoved file.
- groovy: base-files 11ubuntu12
-rw-r--r-- 1 root root 0 set 11 10:20 /etc/default/motd-news.wasremoved
If motd-news-config is later installed, maybe via ubuntu-server, then
the presence of this file will disable motd-news by default, which is
unintended as it's meant to be enabled on a server.
** Description changed:
[Impact]
A fresh install of base-files, like done when using debootstrap, using the base-files from the -updates repository (in the case of ubuntu stable releases), will leave an empty /etc/default/motd-news.wasremoved file. This file is an artifact of the mechanism used to handle a corner case in the previous SRU where it would signal the motd-news-config package to install /etc/default/motd-news with ENABLED=0. See testcases (h) and (i) in the previous base-files SRU at https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575 for details. In test case (i) it was acked that the empty .wasremoved file was lying around, but its impact was deemed not relevant (see [other info] item (a)).
Another case where /etc/default/motd-news.wasremoved would be created
when it shouldn't be is when you have just base-files installed (and no
ubuntu-server or motd-news-config) and did a reinstall of base-files, or
an upgrade. It would again touch /etc/default/motd-news.wasremoved.
The consequence of having /etc/default/motd-news.wasremoved when it's
unintended is that a follow-up install of ubuntu-server, or motd-news-
config for that matter, will install /etc/default/motd-news with
ENABLED=0 instead of ENABLED=1.
This was the case of the groovy debootstrap which resulted in this bug
being filed. While debootstrap won't mix multiple repositories (like
release with updates), and thus this isn't easily a problem in released
versions of ubuntu, the groovy case was the one that was doing a fresh
install of base-files with the buggy touch /etc/default/motd-
news.wasremoved, and a subsequent install of ubuntu-server left motd-
news disabled in groovy images produced by such a method (debootstrap).
These are the scenarios I was able to come up with in which a stable
release could be affected by this bug:
a) debootstrap with release and updates pocket enabled
There are no config options that I'm aware of that would tell debootstrap to use multiple pockets when creating a chroot, but let's say it was done by hacking the script or something else. It would then be the same case as groovy until this fix: subsequent installations of ubuntu-server or motd-news-config would default to having motd-news disabled
b) A system that has just base-files from the previous SRU installed,
and no ubuntu-server and no motd-news-config. If base-files were updated
again and without the fix presented here (let's say, another SRU instead
of this one), it would create /etc/default/motd-news.wasremoved, and
again, a subsequent install of ubuntu-server or motd-news-config would
install motd-news in a disabled state
c) Any other case where the postinst script of base-files is run again
without the fix presented here, and when there is no /etc/default/motd-
news{,.dpkg*} file present.
To avoid creating /etc/default/motd-news.wasremoved when we shouldn't, the maintainer scripts were changed as follows:
- motd-news-config postinst: always remove the .wasremoved file in configure if found, regardless if /etc/default/motd-news was sed'ed or not, or if we are upgrading or on a first install
- base-files postinst: guard the creation of .wasremoved with:
- Only during an upgrade
- Only if ubuntu-server is installed (via a dpkg -l check)
[Test Case]
* On the system under test, remove motd-news-config and ubuntu-server if they are installed, and keep base-files from the update pocket. Something like this:
sudo apt update
sudo apt purge motd-news-config ubuntu-server
apt-cache policy base-files <-- to verify it's from updates
* In this scenario, you should have no /etc/default/motd* files:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
* reinstall base-files:
sudo apt install --reinstall base-files
* Before this SRU, this would create /etc/default/motd-news.wasremoved:
$ ll /etc/default/motd*
-rw-r--r-- 1 root root 0 Sep 16 20:24 /etc/default/motd-news.wasremoved
With the package from proposed for this SRU installed, no such file is created:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
[Regression Potential]
This SRU is further changing maintainer scripts, to address an issue in the previous maintainer script. Should there be new regressions or new issues, it might get harder and harder to fix them.
I did wonder about the `dpkg -l` call in base-files' postinst. I worried
about locks, or pre-dependencies, but dpkg was already being used in
this script, although not with -l (list), just a version comparison. But
at least it's already installed.
My other worry was with the dpkg -l output and which flags I should
check to determine if ubuntu-server was installed. "^ii" doesn't work,
because ubuntu-server might be being upgraded in the same apt
transaction, but ^i seemed good enough. Furthermore, I changed the check
for a package name that doesn't exist, to see if dpkg -l would complain
and fail the whole script (which runs with set -e), but it was ok and
just behaved as if the package wasn't installed, which is what we need.
[Other Info]
+ The previous SRU at https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575 and its attached merge proposals has more detailed info about the history of this motd-news split, and things that were considered.
- * Anything else you think is useful to include
- * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board
- * and address these questions in advance
+ Manually, I used debootstrap with --make-tarball, replace the base-files
+ deb, and --unpack-tarball, to simulate debootstrap with an updated base-
+ files, to confirm this change here would fix the debootstrap problem,
+ and it worked. But I deemed it too complicated to describe as a testcase
+ for this SRU. If you, dear SRU reviewer, would prefer this test to be
+ added, please let me know.
[Original Description]
When debootstrapping groovy, we see an empty /etc/default/motd-
news.wasremoved file.
- groovy: base-files 11ubuntu12
-rw-r--r-- 1 root root 0 set 11 10:20 /etc/default/motd-news.wasremoved
If motd-news-config is later installed, maybe via ubuntu-server, then
the presence of this file will disable motd-news by default, which is
unintended as it's meant to be enabled on a server.
** Also affects: base-files (Ubuntu Xenial)
Importance: Undecided
Status: New
** Also affects: base-files (Ubuntu Bionic)
Importance: Undecided
Status: New
** Changed in: base-files (Ubuntu Xenial)
Assignee: (unassigned) => Andreas Hasenack (ahasenack)
** Changed in: base-files (Ubuntu Bionic)
Assignee: (unassigned) => Andreas Hasenack (ahasenack)
** Changed in: base-files (Ubuntu Xenial)
Status: New => In Progress
** Changed in: base-files (Ubuntu Bionic)
Status: New => In Progress
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https://bugs.launchpad.net/bugs/1895302
Title:
groovy debootstrap leaves /e/d/motd-news.wasremoved around
Status in base-files package in Ubuntu:
In Progress
Status in base-files source package in Xenial:
In Progress
Status in base-files source package in Bionic:
In Progress
Status in base-files source package in Focal:
In Progress
Bug description:
[Impact]
A fresh install of base-files, like done when using debootstrap, using the base-files from the -updates repository (in the case of ubuntu stable releases), will leave an empty /etc/default/motd-news.wasremoved file. This file is an artifact of the mechanism used to handle a corner case in the previous SRU where it would signal the motd-news-config package to install /etc/default/motd-news with ENABLED=0. See testcases (h) and (i) in the previous base-files SRU at https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575 for details. In test case (i) it was acked that the empty .wasremoved file was lying around, but its impact was deemed not relevant (see [other info] item (a)).
Another case where /etc/default/motd-news.wasremoved would be created
when it shouldn't be is when you have just base-files installed (and
no ubuntu-server or motd-news-config) and did a reinstall of base-
files, or an upgrade. It would again touch /etc/default/motd-
news.wasremoved.
The consequence of having /etc/default/motd-news.wasremoved when it's
unintended is that a follow-up install of ubuntu-server, or motd-news-
config for that matter, will install /etc/default/motd-news with
ENABLED=0 instead of ENABLED=1.
This was the case of the groovy debootstrap which resulted in this bug
being filed. While debootstrap won't mix multiple repositories (like
release with updates), and thus this isn't easily a problem in
released versions of ubuntu, the groovy case was the one that was
doing a fresh install of base-files with the buggy touch /etc/default
/motd-news.wasremoved, and a subsequent install of ubuntu-server left
motd-news disabled in groovy images produced by such a method
(debootstrap).
These are the scenarios I was able to come up with in which a stable
release could be affected by this bug:
a) debootstrap with release and updates pocket enabled
There are no config options that I'm aware of that would tell debootstrap to use multiple pockets when creating a chroot, but let's say it was done by hacking the script or something else. It would then be the same case as groovy until this fix: subsequent installations of ubuntu-server or motd-news-config would default to having motd-news disabled
b) A system that has just base-files from the previous SRU installed,
and no ubuntu-server and no motd-news-config. If base-files were
updated again and without the fix presented here (let's say, another
SRU instead of this one), it would create /etc/default/motd-
news.wasremoved, and again, a subsequent install of ubuntu-server or
motd-news-config would install motd-news in a disabled state
c) Any other case where the postinst script of base-files is run again
without the fix presented here, and when there is no /etc/default
/motd-news{,.dpkg*} file present.
To avoid creating /etc/default/motd-news.wasremoved when we shouldn't, the maintainer scripts were changed as follows:
- motd-news-config postinst: always remove the .wasremoved file in configure if found, regardless if /etc/default/motd-news was sed'ed or not, or if we are upgrading or on a first install
- base-files postinst: guard the creation of .wasremoved with:
- Only during an upgrade
- Only if ubuntu-server is installed (via a dpkg -l check)
[Test Case]
* On the system under test, remove motd-news-config and ubuntu-server if they are installed, and keep base-files from the update pocket. Something like this:
sudo apt update
sudo apt purge motd-news-config ubuntu-server
apt-cache policy base-files <-- to verify it's from updates
* In this scenario, you should have no /etc/default/motd* files:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
* reinstall base-files:
sudo apt install --reinstall base-files
* Before this SRU, this would create /etc/default/motd-news.wasremoved:
$ ll /etc/default/motd*
-rw-r--r-- 1 root root 0 Sep 16 20:24 /etc/default/motd-news.wasremoved
With the package from proposed for this SRU installed, no such file is created:
$ ll /etc/default/motd*
ls: cannot access '/etc/default/motd*': No such file or directory
[Regression Potential]
This SRU is further changing maintainer scripts, to address an issue in the previous maintainer script. Should there be new regressions or new issues, it might get harder and harder to fix them.
I did wonder about the `dpkg -l` call in base-files' postinst. I
worried about locks, or pre-dependencies, but dpkg was already being
used in this script, although not with -l (list), just a version
comparison. But at least it's already installed.
My other worry was with the dpkg -l output and which flags I should
check to determine if ubuntu-server was installed. "^ii" doesn't work,
because ubuntu-server might be being upgraded in the same apt
transaction, but ^i seemed good enough. Furthermore, I changed the
check for a package name that doesn't exist, to see if dpkg -l would
complain and fail the whole script (which runs with set -e), but it
was ok and just behaved as if the package wasn't installed, which is
what we need.
[Other Info]
The previous SRU at https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575 and its attached merge proposals has more detailed info about the history of this motd-news split, and things that were considered.
Manually, I used debootstrap with --make-tarball, replace the base-
files deb, and --unpack-tarball, to simulate debootstrap with an
updated base-files, to confirm this change here would fix the
debootstrap problem, and it worked. But I deemed it too complicated to
describe as a testcase for this SRU. If you, dear SRU reviewer, would
prefer this test to be added, please let me know.
[Original Description]
When debootstrapping groovy, we see an empty /etc/default/motd-
news.wasremoved file.
- groovy: base-files 11ubuntu12
-rw-r--r-- 1 root root 0 set 11 10:20 /etc/default/motd-news.wasremoved
If motd-news-config is later installed, maybe via ubuntu-server, then
the presence of this file will disable motd-news by default, which is
unintended as it's meant to be enabled on a server.
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