2015-09-21 21:24 GMT+02:00 J. Bruce Fields <bfields@xxxxxxxxxxxx>:
> On Fri, Sep 18, 2015 at 05:56:11PM -0400, bfields wrote:
>> On Sat, Sep 05, 2015 at 12:27:17PM +0200, Andreas Gruenbacher wrote:
>> > + /*
>> > + * If the owner mask contains permissions which are not in the group
>> > + * mask, the group mask contains permissions which are not in the other
>> > + * mask, or the owner class contains permissions which are not in the
>>
>> s/owner class/owner mask?
>>
>> > + * other mask, we may need to propagate permissions up from the
>> > + * everyone@ allow ace. The third condition is implied by the first
>> > + * two.
>> > + */
>> > + if (!((acl->a_owner_mask & ~acl->a_group_mask) ||
>> > + (acl->a_group_mask & ~acl->a_other_mask)))
>> > + return 0;
>>
>> The code looks right, but I don't understand the preceding comment.
>>
>> For example,
>>
>> owner mask: rw
>> group mask: wx
>> other mask: rw
>>
>> satisfies the first two conditions, but not the third.
>>
>> Also, I don't understand why the first condition would imply that we
>> might need to propagate permissions.
>
> OK, maybe I get the part about the owner mask containing permissions
> not in the group mask: we'll need to insert a deny ace for the bits in
> the other mask but not in the group mask, and then we'll need an allow
> ace for the owner to get those bits back. I think?
That is indeed the reason, and it also seems clear that this wasn't
documented well enough. Let me remove the offending comment and tiny
optimization, and add better comments instead.
>> > + if (richace_is_allow(ace) || richace_is_deny(ace)) {
>
> The v4 spec allows aces other than allow and deny aces (audit and
> alarm), but I didn't think you were implementing those.
Right, I don't see that happening. I'll remove that as well.
Thanks,
Andreas
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