[buildd-tools-devel] Bug#605939: Bug#605939: Bug#605939: Regression: Chroots with periods in the name no longer work.

[Roger Leigh]

tags 605939 + fixed-upstream pending
thanks

On Sun, Dec 05, 2010 at 10:22:31PM +0000, Roger Leigh wrote:
> severity 605939 serious
> thanks
> 
> Given the fact that this can break people's configurations when
> upgrading from lenny, I'm inclined to raise the severity to
> serious.
> 
> I'm happy to fix this upstream now that I've gone through the
> code to check exactly what the name is used for.  I've made
> an initial commit on the master and schroot-1.4 branches to
> fix this, and once we're sure it also doesn't look at editor
> backups in addition to dpkg conffile data, I'll make a new
> release with this bugfix.

This is hopefully fixed in git.  This is the logic we're using:

bool
sbuild::is_valid_sessionname (std::string const& name)
{
  bool match = false;

  static regex file_namespace("^[^:/,.][^:/,]*$");
  static regex editor_backup("~$");
  static regex debian_dpkg_conffile_cruft("dpkg-(old|dist|new|tmp)$");

  if (regex_search(name, file_namespace) &&
      !regex_search(name, editor_backup) &&
      !regex_search(name, debian_dpkg_conffile_cruft)) {
    match = true;
  }

  return match;
}

If there are no objections and we're correctly picking out all editor
and dpkg backup files, I think this is fixed.

From the updated documentation:

CHROOT NAMES
       A  number of characters or words are not permitted in a chroot name, session
       name or configuration filename.  The name may not contain a  leading  period
       (‘.’).   The characters ‘:’ (colon), ‘,’ (comma) and ‘/’ (forward slash) are
       not permitted anywhere in the name.  The name may also not contain a  trail‐
       ing tilde (‘~’).  The rationale for these restrictions is given below.

       ‘.’    A  leading period could be used to create a name with a relative path
              in it, in combination with ‘/’, and this could allow  overwriting  of
              files on the host filesystem.  Not allowing this character also means
              hidden files cannot be created.  It also means  some  editor  backups
              are  automatically ignored.  Periods are allowed anywhere else in the
              name.

       ‘:’    A colon is used as a namespace delimiter, and so is not permitted  as
              part  of  a  chroot or session name.  LVM snapshot names may also not
              contain this character due to a naming restriction by lvcreate(8).

       ‘/’    Names containing this character are not valid filenames.   A  forward
              slash would potentially allow creation of files in subdirectories.

       ‘,’    Commas are used to separate items in lists.  Aliases are separated by
              commas and hence can't contain commas in their name.

       ‘~’    Filenames containing trailing  tildes  are  used  for  editor  backup
              files,  which  are  ignored.  Tildes are allowed anywhere else in the
              name.

       ‘dpkg-old’
       ‘dpkg-dist’
       ‘dpkg-new’
       ‘dpkg-tmp’
              These names may not appear at the end of a  name.   These  are  saved
              copies  of  conffiles  used  by the dpkg package manager, and will be
              ignored.


Regards,
Roger

-- 
  .''`.  Roger Leigh
 : :' :  Debian GNU/Linux             http://people.debian.org/~rleigh/
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