SystemError: E:Opening /etc/apt/sources.list.d/private-ppa.launchpad.<something>list - ifstream::ifstream (13: Permission denied)

[Natalia Bidart]

Binary package hint: python-apt

When creating a Cache instance with:

cache = apt.Cache()

if any of the sources file is not readable by the current user, we get this trace:

   cache = apt.Cache()
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 88, in __init__
    self.open(progress)
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 130, in open
    self._list.read_main_list()
SystemError: E:Opening /etc/apt/sources.list.d/private-ppa.launchpad_<something>.list - ifstream::ifstream (13: Permission denied)

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: python-apt 0.7.100.2ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-7.39-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Thu Mar 31 15:09:10 2011
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: python-apt
UpgradeStatus: No upgrade log present (probably fresh install)

[Julian Andres Klode (juliank)]

There's nothing we can do here. APT needs read access to all sources.list, configuration, and preferences files. Marking a sources.list file as unreadable is not supported, and useless, as the cache and /var/lib/apt/lists/ will contain the data from the repository anyway.

[Michael Terry (mterry)]

Can this be reconsidered or at least re-assigned? It's very easy to get into this situation:

1) Install a for-purchase app in Software Center
2) Software Center installs a sources.list.d file with -rw-r----- (root, admin) privileges
3) Now any user not in the admin group will hit this crash

[Julian Andres Klode (juliank)]

I don't see how this can be fixed and I do not want to fix it, but I am reassigning it to APT, if that makes you happy.

[David Kalnischkies (donkult)]

And i don't know what APT should make different here. I mean, we can't read the file, so we can't know all sources, so the Cache will be incomplete, so the solution will be incomplete - if we found any. But most likely we will "just" miss important security updates or alike.

So, if we have such a problem, why we shouldn't be allowed to error out instead of pretending that everything is okay?

That setting a sources.list(.d) file as non-readable isn't very useful said already Julian, so you might better of asking the program(s) which created these files to stop making them non-readable…

Sidenote: If it's non-readable because a password is written in it directly they should having a look at https certificates or the netrc-like config file for user-credentials instead…

[Matthew Paul Thomas (mpt)]

I reported the equivalent bug for Ubuntu Software Center as bug 852003.