[Bug-tar] ACL support, extract and default ACLs

[Juan J. Martínez]

Hello,

I'm experiencing a possible problem with ACL support with the --acls
flag and tar 1.27:

 when a tarball is extracted using --acls, a default ACL is created for
every file/dir extracted from the tarball (with no archived ACLs I think).

I've run some tests and I've found that:

 - a tar without ACLs (using GNU tar formar -that doesn't support ACLs-)
 - a POSIX tar without ACLs
 - a POSIX tar with ACLs

...all of these cases add a default ACL when extracting files with no
archived ACLs.

I was expecting the stored ACLs to be restored when extracting contents,
but not the addition of that default ACLs that was not present in the
archived contents (see the case of a tarball in GNU tar format).

This behaviour causes problems when creating and restoring a tarball
with a complete filesystem because lots of applications/tools can't
handle ACLs properly.

I'd like to use the --acls flag to preserve *existing* ACLs when
extracting files/dirs and not add a default ACL.

Markus Steinborn wrote about ACL support and in his list of points that
need improvement was:

> Optional (3): Do not store ACLs iff ACL contains just the normal
> user, group and other permissions, i. .e. the ACL is an compatibility
> ACL.

(I wasn't subscribed to the list back then)

I don't know if it is related or not, I'd appreciate comments about this.

Regards,

Juan