[Bug-tar] ACL entries contain comments which may break compatibility

[Michał Górny]

Hi,

Thanks for fixing the previous bug I reported.  Sadly, I just managed to
accidentally find another one.  When ACL mask restricts effective ACL
entries, getfacl(1) reports the effective permissions as a comment,
e.g.:

user:nobody:rw-                 #effective:r--

It seems that GNU tar writes that comment as part of the pax header,
and e.g. libarchive does not restore the ACL correctly.

To reproduce:

touch input.txt
setfacl -m nobody:rw input.txt 
setfacl -m m:r input.txt 
tar --format=pax --acls -cf test.tar input.txt

The resulting pax attributes contain:

95 SCHILY.acl.access=user::rw-
user:nobody:rw- #effective:r--
group::r--
mask::r--
other::r--

Now extract e.g. with bsdtar (from libarchive):

$ bsdtar -xf test.tar --acls

And the u:nobody ACL is gone.

-- 
Best regards,
Michał Górny

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