Re: Bugreport on Ubuntu LTS: not ok - 2 Objects creation does not break ACLs with restrictive umask

From: Jeff King <peff@peff.net>
Date: Jun 5, 2012, 14:28 UTC
Message-ID: <20120605142813.GA17238@sigill.intra.peff.net>
In-Reply-To: <20120605141039.GB15640@sigill.intra.peff.net>

On Tue, Jun 05, 2012 at 10:10:39AM -0400, Jeff King wrote:

Show 11 quoted lines

> On Tue, Jun 05, 2012 at 10:04:49AM -0400, Jeff King wrote:
> 
> >   # and create some files with different permissions
> >   perl -MFcntl -e '
> >     sysopen(X, "a", O_WRONLY|O_CREAT, 0666);
> >     sysopen(X, "b", O_WRONLY|O_CREAT, 0600);
> >   '
> Hmm, no I'm wrong. That is OK, as the mask should be restricted by the
> group permission (and it is on ext4, too). But when I traced through
> git, the tmp_obj_* files are created with the right permissions on ext4,
> but not on ecryptfs. Let me trace through it again...<sigh>

OK, here's the _real_ issue. Git creates with mode 0444, which should still allow read in the mask. But it's the restrictive umask at the top of the test script that causes the problem. Try this:

  setfacl -m m:rwx .
  perl -MFcntl -e 'sysopen(X, "a", O_WRONLY|O_CREAT, 0444)'
  umask 077
  perl -MFcntl -e 'sysopen(X, "b", O_WRONLY|O_CREAT, 0444)'
  getfacl a b

On ext4, both files will have the read bit set in the mask. On ecryptfs, "b" will have an empty mask. I think the wrong thing is that we should not be respecting umask at all when default ACLs are in play, and ecryptfs is getting that wrong. But I'm having trouble digging up an authoritative source.

-Peff