Re: [Acl-devel] [Bug-tar] gtar's ACL support is still unusable

[Pavel Raiskup]

Thanks for the report! +cc acl-devel

On Thursday, March 14, 2019 2:51:10 PM CET Joerg Schilling wrote:
> Trying to unpack the reference archives for the POSIX ACL proposal from
> 1993 that was withdrawn in 1997 results in something like:
> 
> /tmp/tar-1.31/src/tar --acls -xpf acl-test3.tar.gz     
> /tmp/tar-1.31/src/tar: default/dir2: Warnung: Funktion acl_from_text 
> fehlgeschlagen
> /tmp/tar-1.31/src/tar: default/dir3: Warnung: Funktion acl_from_text 
> fehlgeschlagen
> /tmp/tar-1.31/src/tar: default: Warnung: Funktion acl_from_text fehlgeschlagen
> /tmp/tar-1.31/src/tar: default: Warnung: Funktion acl_from_text fehlgeschlagen

This is because we use acl_from_text() without pre-filtering, which
doesn't accept the fourth UID/GID number value in e.g.
ACL record 'user:joe:rwx:503' (stored in the archive):

   $ tar -t -vv --acls -f acl-test5.tar
   ...
   drwxrwxr-x+ gruenbacher/assis 0 2001-11-04 04:43 default/dir2/
     a: user::rwx,user:joe:rwx:503,group::r-x,mask::rwx,other::r-x
   ...
   $ tar -xf --acls -f acl-test5.tar
   ...
   tar: default/dir2: Warning: Cannot acl_from_text: Invalid argument
   ...

I did not notice this so far, since we don't add the fourth numeric
argument to the SCHILY.acl.access header;  neither star does that (on
Linux at least, despite the claim in manual page).

I'm curious whether we should think about fixing this in acl_from_text()
function directly, or whether this should be handled solely in archivers.

Pavel