> On Fri, 20 Oct 2017 10:47:48 +0300 > Elena Reshetova <elena.reshetova@xxxxxxxxx> wrote: > > > atomic_t variables are currently used to implement reference > > counters with the following properties: > > - counter is initialized to 1 using atomic_set() > > - a resource is freed upon counter reaching zero > > - once counter reaches zero, its further > > increments aren't allowed > > - counter schema uses basic atomic operations > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > Such atomic variables should be converted to a newly provided > > refcount_t type and API that prevents accidental counter overflows > > and underflows. This is important since overflows and underflows > > can lead to use-after-free situation and be exploitable. > > > > The variable urdev.ref_count is used as pure reference counter. > > Convert it to refcount_t and fix up the operations. > > > > Suggested-by: Kees Cook <keescook@xxxxxxxxxxxx> > > Reviewed-by: David Windsor <dwindsor@xxxxxxxxx> > > Reviewed-by: Hans Liljestrand <ishkamiel@xxxxxxxxx> > > Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx> > > Added to s390/linux:features for the next merge window. Thanks. Thank you very much! Best Regards, Elena. > > -- > blue skies, > Martin. > > "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
