From: pk on
Jonathan de Boyne Pollard wrote:

>> So in the hypothetical case at hand, where the file owner is allowed
>> to change ownership of the file, would a "chown" process started by
>> that user be classified as "having appropriate privileges" or not?
>>
> There are two common models:
>
>[snip good stuff]

Ok, I guess the "appropriate privileges to preserve the SxID bits" (as
opposed to "appropriate privileges to call chown()") is what I was missing.
Thanks all for the explanations.