On Sat, Sep 23, 2017 at 10:05:56PM -0400, Meng Xu wrote: > Hi Peter and Ingo, > > As a reminder, this is a very similar issue to perf_copy_attr (see following > patch) > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=f12f42acdbb577a12eecfcebbbec41c81505c4dc > > <https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=f12f42acdbb577a12eecfcebbbec41c81505c4dc> > > Will it be fixed as well?
If someone were to actually send me the patch.. probably. > > On Aug 29, 2017, at 3:10 PM, Meng Xu <meng...@gatech.edu> wrote: > > > > From: Meng Xu <mengxu.gat...@gmail.com> > > > > `attr->size` after the second fetch `copy_from_user(attr, uattr, size)`, > > can be different from what is initially fetched in and checked > > `get_user(size, &uattr->size)` by racing condition in the userspace. > > > > The issue and the patch are both similar to commit f12f42a > > (in kernel/events/core.c). > > > > Signed-off-by: Meng Xu <mengxu.gat...@gmail.com> > > --- > > kernel/sched/core.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 0869b20..c22d2b4 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -4349,6 +4349,8 @@ static int sched_copy_attr(struct sched_attr __user > > *uattr, struct sched_attr *a > > if (ret) > > return -EFAULT; > > > > + attr->size = size; > > + > > /* > > * XXX: Do we want to be lenient like existing syscalls; or do we want > > * to be strict and return an error on out-of-bounds values? > > -- > > 2.7.4 > > >
