Re: [RFC v6 08/40] richacl: Compute maximum file masks from an acl

[Andreas Gruenbacher <agruenba@redhat.com>]

2015-09-02 21:54 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>:
>> +     richacl_for_each_entry_reverse(ace, acl) {
>> +             if (richace_is_inherit_only(ace))
>> +                     continue;
>> +
>> +             if (richace_is_owner(ace) ||
>> +                 (richace_is_unix_user(ace) &&
>> +                  uid_eq(ace->e_id.uid, owner))) {
>> +                     if (richace_is_allow(ace))
>> +                             acl->a_owner_mask |= ace->e_mask;
>> +                     else if (richace_is_deny(ace))
>> +                             acl->a_owner_mask &= ~ace->e_mask;
>> +             } else if (richace_is_everyone(ace)) {
>> +                     if (richace_is_allow(ace)) {
>> +                             acl->a_owner_mask |= ace->e_mask;
>> +                             acl->a_group_mask |= ace->e_mask & gmask;
>> +                             acl->a_other_mask |= ace->e_mask;
>> +                     } else if (richace_is_deny(ace)) {
>> +                             acl->a_owner_mask &= ~ace->e_mask;
>> +                             acl->a_group_mask &= ~ace->e_mask;
>> +                             acl->a_other_mask &= ~ace->e_mask;
>> +                     }
>> +             } else {
>> +                     if (richace_is_allow(ace)) {
>> +                             acl->a_owner_mask |= ace->e_mask & gmask;
>> +                             acl->a_group_mask |= ace->e_mask & gmask;
>
> I think we do that because we don't (we can't) know whether the owner
> might match this ace, so we assume that it will match, as that's what
> gives us the maximum.

Yes.

> But on first glance this is a little counterintuitive and maybe worth a
> comment.

I agree.

Thanks,
Andreas