[Bug 1895302] Re: groovy debootstrap leaves /e/d/motd-news.wasremoved around

Andreas Hasenack 1895302 at bugs.launchpad.net
Wed Sep 16 19:46:28 UTC 2020 

** 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 low (see [other info] item (a)).
  
-  * An explanation of the effects of the bug on users and
+ 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.
  
-  * justification for backporting the fix to the stable release.
+ 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.
  
-  * In addition, it is helpful, but not required, to include an
-    explanation of how the upload fixes this bug.
+ 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 strictly 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).
+ 
+ For stable releases, the impact is lessened because debootstrap will
+ grab the release pocket for its job, and base-files from that pocket, in
+ all ubuntu releases other than groovy, does not have the code that
+ creates /etc/default/motd-news.wasremoved.
+ 
+ This would affect a stable release anytime the postinst script from
+ base-files from the previous SRU is run and there are no /etc/default
+ /motd-news{,.dpkg*} files present. This could be a system which just
+ doesn't have ubuntu-server or motd-news-config installed, in which case
+ creating the .wasremoved file is wrong. Or a system which has those
+ packages installed, and the user erroneously, in an attempt to disable
+ motd-news, removed /etc/default/motd-news, in which case it's correct to
+ create /etc/default/motd-news.wasremoved.
+ 
+ If debootstrap is somehow coached into using the release and updates
+ pocket, then the stable release it's bootstrapping would suffer from
+ this bug in the same way that groovy did: base-files would be installed
+ without ubuntu-server or motd-news-config, and an empty /etc/default
+ /motd-news.wasremoved file would be creating, disabling motd-news in any
+ future installation of motd-news-config or ubuntu-server.
+ 
  
  [Test Case]
  
-  * detailed instructions how to reproduce the bug
+  * detailed instructions how to reproduce the bug
  
-  * these should allow someone who is not familiar with the affected
-    package to reproduce the bug and verify that the updated package fixes
-    the problem.
+  * these should allow someone who is not familiar with the affected
+    package to reproduce the bug and verify that the updated package fixes
+    the problem.
  
  [Regression Potential]
  
-  * discussion of how regressions are most likely to manifest as a result
+  * 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.
+  * 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.
+  * This both shows the SRU team that the risks have been considered,
+    and provides guidance to testers in regression-testing the SRU.
  
  [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
  
+  * 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.

-- 
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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 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 low (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 strictly 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).

  For stable releases, the impact is lessened because debootstrap will
  grab the release pocket for its job, and base-files from that pocket,
  in all ubuntu releases other than groovy, does not have the code that
  creates /etc/default/motd-news.wasremoved.

  This would affect a stable release anytime the postinst script from
  base-files from the previous SRU is run and there are no /etc/default
  /motd-news{,.dpkg*} files present. This could be a system which just
  doesn't have ubuntu-server or motd-news-config installed, in which
  case creating the .wasremoved file is wrong. Or a system which has
  those packages installed, and the user erroneously, in an attempt to
  disable motd-news, removed /etc/default/motd-news, in which case it's
  correct to create /etc/default/motd-news.wasremoved.

  If debootstrap is somehow coached into using the release and updates
  pocket, then the stable release it's bootstrapping would suffer from
  this bug in the same way that groovy did: base-files would be
  installed without ubuntu-server or motd-news-config, and an empty
  /etc/default/motd-news.wasremoved file would be creating, disabling
  motd-news in any future installation of motd-news-config or ubuntu-
  server.

  
  [Test Case]

   * detailed instructions how to reproduce the bug

   * these should allow someone who is not familiar with the affected
     package to reproduce the bug and verify that the updated package fixes
     the problem.

  [Regression Potential]

   * 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.

  [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.

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