Skip to content
Browse files

futex: Prevent overflow by strengthen input validation

UBSAN reports signed integer overflow in kernel/futex.c:

 UBSAN: Undefined behaviour in kernel/futex.c:2041:18
 signed integer overflow:
 0 - -2147483648 cannot be represented in type 'int'

Add a sanity check to catch negative values of nr_wake and nr_requeue.

Signed-off-by: Li Jinyue <>
Signed-off-by: Thomas Gleixner <>
  • Loading branch information...
LiJinyue authored and Thomas Gleixner committed Dec 14, 2017
1 parent c1e2f0e commit fbe0e839d1e22d88810f3ee3e2f1479be4c0aa4a
Showing with 3 additions and 0 deletions.
  1. +3 −0 kernel/futex.c
@@ -1878,6 +1878,9 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_q *this, *next;

if (nr_wake < 0 || nr_requeue < 0)
return -EINVAL;

* When PI not supported: return -ENOSYS if requeue_pi is true,
* consequently the compiler knows requeue_pi is always false past

0 comments on commit fbe0e83

Please sign in to comment.
You can’t perform that action at this time.