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

Jeff King [off-list ref] writes:

[+cc ecryptfs@vger, as I think this is an ecryptfs bug]

On Tue, Jun 05, 2012 at 10:28:13AM -0400, Jeff King wrote:

quoted

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.

Reading the withdrawn posix 1003.1e and "man 5 acl", it seems pretty
clear that if a default ACL is present, it should be used, and umask
consulted only if it is not (so the umask should not be making a
difference in this case).

The reproduction recipe above shows the minimum required to trigger it;
adding a more realistic default ACL (with actual entries for users) does
not seem to make a difference.

Thanks; so combining the above with your earlier patch to 1304 we
would have a good detection for SETFACL prerequisite?