[Bug 1696066] Re: Postfix module - Mailman wrapper - Couldn't write data/aliases.db and data/virtual-mailman.db files

Laurent Declercq 1696066 at bugs.launchpad.net
Tue Jun 6 04:03:20 EDT 2017


** Description changed:

  Dear project leader
  
  At least in version 2.1.23, there is a bug regarding permissions set for
  Mailman data/aliases table and Mailman data/virtual-mailman map when
  these files are created from scratch.
  
  Here I describe the current behavior for the Mailman data/aliases table
  only but the problem is identical for the Mailman data/virtual-mailman
  map.
  
  In order, the following conditions have to be met:
  
  - Postfix need read access to the aliases.db file
  - Mailman like to be owner of those files and the Mailman group needs write access to them
  
  I. Postfix needs a read access to the aliases.db file
  
  We can either set permissions as 0660 and add postfix user to mailman
  group (what I've done), or set the permissions as 0664
  
  II. Mailman group needs a write access to those files at any time
  
  The following behavior has been observed:
  
  When creating a new list on command line, using bin/newlist script as
  follow:
  
      # newlist -u virtualhost foobar
  
  the files will be created as follow:
  
  -rw-rw---- 1 root list aliases
  -rw-r----- 1 root list aliases.db
  
  The same thing has been observed when recreating the file from scratch
  using bin/genaliases:
  
  -rw-rw---- 1 root list aliases
  -rw-r----- 1 root list aliases.db
  
  Note that in both cases, files were not present. Thus, they were created
  from scratch.
  
  As you can see here, the Mailman data/aliases table is created with the
  expected group and permissions but the data/aliases.db file is only
  writable by owner. From the POSTALIAS(1) command point of view, that is
  the expected behavior: The file is created with the same group and other
  read permissions as their source file.
  
  The problem here is that with those permissions, creating a list through
  Mailman interface later on will result in a permissions denied error
  because the Mailman group, through the wrapper, cannot write (update)
  the aliases.db file (no write permissions).
  
  That is really a problem. Of course, one can just pre-create the files
  as follow:
  
  # cd /var/lib/mailman
  # sg list -c "touch data/aliases && postalias data/aliases"
  # chmod 0660 data/aliases*
  
  but that seem tedious. What if at some point (for any reason), the files
  get recreated from scratch?
  
  So, from my point of view, the MTA/Postfix.py module should always set
  correct permissions on resulting *.db file, after running POSTALIAS(1)
  command to be sure that Mailman group has write permissions, at least
- when the files are created from scratch.
+ when the files are created from scratch. Eg:
+ 
+ IF NOT EXISTS aliases:
+    Touch data/aliases data/aliases.db with correct permissions (066x)
+    Add alias entries into aliases as usually
+    Run POSTALIAS(1) command as usually
+ 
+ Then, we are fine.
  
  Thank you.

** Description changed:

  Dear project leader
  
  At least in version 2.1.23, there is a bug regarding permissions set for
  Mailman data/aliases table and Mailman data/virtual-mailman map when
  these files are created from scratch.
  
  Here I describe the current behavior for the Mailman data/aliases table
  only but the problem is identical for the Mailman data/virtual-mailman
  map.
  
  In order, the following conditions have to be met:
  
  - Postfix need read access to the aliases.db file
  - Mailman like to be owner of those files and the Mailman group needs write access to them
  
  I. Postfix needs a read access to the aliases.db file
  
  We can either set permissions as 0660 and add postfix user to mailman
  group (what I've done), or set the permissions as 0664
  
  II. Mailman group needs a write access to those files at any time
  
  The following behavior has been observed:
  
  When creating a new list on command line, using bin/newlist script as
  follow:
  
      # newlist -u virtualhost foobar
  
  the files will be created as follow:
  
  -rw-rw---- 1 root list aliases
  -rw-r----- 1 root list aliases.db
  
  The same thing has been observed when recreating the file from scratch
  using bin/genaliases:
  
  -rw-rw---- 1 root list aliases
  -rw-r----- 1 root list aliases.db
  
  Note that in both cases, files were not present. Thus, they were created
  from scratch.
  
  As you can see here, the Mailman data/aliases table is created with the
  expected group and permissions but the data/aliases.db file is only
  writable by owner. From the POSTALIAS(1) command point of view, that is
  the expected behavior: The file is created with the same group and other
  read permissions as their source file.
  
  The problem here is that with those permissions, creating a list through
  Mailman interface later on will result in a permissions denied error
  because the Mailman group, through the wrapper, cannot write (update)
  the aliases.db file (no write permissions).
  
  That is really a problem. Of course, one can just pre-create the files
  as follow:
  
  # cd /var/lib/mailman
  # sg list -c "touch data/aliases && postalias data/aliases"
  # chmod 0660 data/aliases*
  
  but that seem tedious. What if at some point (for any reason), the files
  get recreated from scratch?
  
  So, from my point of view, the MTA/Postfix.py module should always set
- correct permissions on resulting *.db file, after running POSTALIAS(1)
- command to be sure that Mailman group has write permissions, at least
- when the files are created from scratch. Eg:
+ correct permissions on *.db file,  to be sure that Mailman group has
+ write permissions, at least when the files are created from scratch. Eg:
  
  IF NOT EXISTS aliases:
-    Touch data/aliases data/aliases.db with correct permissions (066x)
-    Add alias entries into aliases as usually
-    Run POSTALIAS(1) command as usually
+    Touch data/aliases data/aliases.db with correct permissions (066x)
+    Add alias entries into aliases as usually
+    Run POSTALIAS(1) command as usually
  
  Then, we are fine.
  
  Thank you.

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https://bugs.launchpad.net/bugs/1696066

Title:
  Postfix module - Mailman wrapper - Couldn't write data/aliases.db and
  data/virtual-mailman.db files

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