From eaf6ab76430881c30695a9195ce37d6b11b04997 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 20 Oct 2017 10:23:35 +0300 Subject: drivers, net, ethernet: convert clip_entry.refcnt from atomic_t to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable clip_entry.refcnt is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: David S. Miller --- drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h') diff --git a/drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h b/drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h index 35eb43c6bcbb..a0e0ae19649f 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h +++ b/drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h @@ -10,9 +10,11 @@ * release for licensing terms and conditions. */ +#include + struct clip_entry { spinlock_t lock; /* Hold while modifying clip reference */ - atomic_t refcnt; + refcount_t refcnt; struct list_head list; union { struct sockaddr_in addr; -- cgit v1.2.3-59-g8ed1b