Re: [Acl-devel] typo in acl_get_perm?

[Corinna Vinschen]

On Dec 26 17:58, Mike Frysinger wrote:
> On 26 Dec 2015 16:08, Corinna Vinschen wrote:
> > On Dec 26 15:46, Andreas Grünbacher wrote:
> > > 2015-12-26 14:34 GMT+01:00 Corinna Vinschen <address@hidden>:
> > > > On Dec 26 11:57, Andreas Grünbacher wrote:
> > > >> 2015-12-25 15:36 GMT+01:00 Corinna Vinschen <address@hidden>:
> > > > [...]
> > > > The man page doesn't make it clear that only a single permission bit is
> > > > allowed as input.
> > > 
> > > "The [...] function tests if the permission [...] is contained in the
> > > [...] set."
> > > 
> > > So again, what's unclear about that?
> > 
> > Not trying to put too fine a point on it, but isn't the fact that I
> > misunderstood an indicator that, perhaps, more than a single person
> > might misunderstand it?  I'm not the only dumb person out there ;)
> 
> he asked what's unclear in the quoted statement.  what's unclear about that ? 
> ;)
> -mike

Ok, sorry if my mail was unclear on that point.  Let me try again:

Perm is an acl_perm_t, which consists of any combination of ACL_READ|
ACL_WRITE|ACL_EXECUTE.  It's not clear from the man page that only a
single permission bit is allowed here, rather than an arbitrary
combination of the above bits.

And then the code neither actually tests that only a single bit is set,
returning EINVAL if not, nor would its behaviour match the behaviour of
acl_add_perm and acl_delete_perm, both of which allow any combination of
valid acl_perm_t bits.

Alternatively, if a bit combination is allowed as in acl_add_perm and
acl_delete_perm, the test in the code is ok, but the evaluation of the
return value is not (a&b!=0 vs. ~a&b==0).


Corinna

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