"uattr->size" is copied in from user space and checked. However, it is
copied in again after the security check. A malicious user may race to
change it. The fix sets uattr->size to be the checked size.
Signed-off-by: Kangjie Lu <k...@umn.edu>
---
kernel/sched/core.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6fedf3a98581..e868cc25ac2a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4499,6 +4499,9 @@ static int sched_copy_attr(struct sched_attr __user
*uattr, struct sched_attr *a
if (ret)
return -EFAULT;
+ /* In case attr->size was changed in the user space */
+ 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?
--
2.17.1
