From: Meng Xu <[email protected]> `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 <[email protected]> --- 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
