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net: convert netpoll_info.refcnt from atomic_t to refcount_t

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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Reshetova, Elena 2017-06-30 13:08:04 +03:00 committed by David S. Miller
parent 7658b36f1b
commit 433cea4d9b
2 changed files with 5 additions and 4 deletions
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3
include/linux/netpoll.h
View file

@ -11,6 +11,7 @@
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/refcount.h>
union inet_addr { union inet_addr {
__u32 all[4]; __u32 all[4];
@ -34,7 +35,7 @@ struct netpoll {
}; };
struct netpoll_info { struct netpoll_info {
atomic_t refcnt; refcount_t refcnt;
struct semaphore dev_lock; struct semaphore dev_lock;

6
net/core/netpoll.c
View file

@ -632,7 +632,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
skb_queue_head_init(&npinfo->txq); skb_queue_head_init(&npinfo->txq);
INIT_DELAYED_WORK(&npinfo->tx_work, queue_process); INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
atomic_set(&npinfo->refcnt, 1); refcount_set(&npinfo->refcnt, 1);
ops = np->dev->netdev_ops; ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_setup) { if (ops->ndo_netpoll_setup) {
@ -642,7 +642,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
} }
} else { } else {
npinfo = rtnl_dereference(ndev->npinfo); npinfo = rtnl_dereference(ndev->npinfo);
atomic_inc(&npinfo->refcnt); refcount_inc(&npinfo->refcnt);
} }
npinfo->netpoll = np; npinfo->netpoll = np;
@ -821,7 +821,7 @@ void __netpoll_cleanup(struct netpoll *np)
synchronize_srcu(&netpoll_srcu); synchronize_srcu(&netpoll_srcu);
if (atomic_dec_and_test(&npinfo->refcnt)) { if (refcount_dec_and_test(&npinfo->refcnt)) {
const struct net_device_ops *ops; const struct net_device_ops *ops;
ops = np->dev->netdev_ops; ops = np->dev->netdev_ops;