In use after free situations, it is possible for one thread to write to
memory that has just been reallocated to a new user. This could open up
potential security issues.
Close off those potential security holes by terminating the current
thread when kref encounters such a race condition or underflow.
Signed-off-by: Mateusz Guzik <mgu...@redhat.com>
Cc: Rik van Riel <r...@redhat.com>
---
include/linux/kref.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/linux/kref.h b/include/linux/kref.h
index 484604d..c3f8a0a 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -43,8 +43,10 @@ static inline void kref_get(struct kref *kref)
/* If refcount was 0 before incrementing then we have a race
* condition when this kref is freeing by some other thread right now.
* In this case one should use kref_get_unless_zero()
+ *
+ * Terminate the current thread to stop potential security exploits.
*/
- WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2);
+ BUG_ON(atomic_inc_return(&kref->refcount) < 2);
}
/**
--
1.8.3.1
--
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