Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 7 Aug 2013 09:58:09 -0700 | Subject | Re: [PATCH 1/2] kernel/sys.c: return the current gid when error occurs |
| |
On Wed, Aug 7, 2013 at 9:21 AM, Oleg Nesterov <oleg@redhat.com> wrote: > On 08/06, Andy Lutomirski wrote: >> >> I assume that what the man page means is that the return value is >> whatever fsgid was prior to the call. On error, fsgid isn't changed, so >> the return value is still "current". > > Probably... Still > > On success, the previous value of fsuid is returned. > On error, the current value of fsuid is returned. > > looks confusing. sys_setfsuid() always returns the old value. > >> (FWIW, this behavior is awful and is probably the cause of a security >> bug or three, since success and failure are indistinguishable. > > At least this all looks strange. > > I dunno if we can change this old behaviour. I won't be surprized > if someone already uses setfsuid(-1) as getfsuid().
I suspect that changing this without introducing security or other bugs is impossible. If someone wanted to add new_setfsuid that returned an error when it failed, that would be a different story. (I'm not going to do that myself.)
> > And perhaps the man page should be changed. Add Michael.
Agreed. The text is a bit odd.
> > Oleg. >
-- Andy Lutomirski AMA Capital Management, LLC
| |