From mboxrd@z Thu Jan 1 00:00:00 1970 From: Elena Reshetova Subject: [PATCH 10/17] net: convert in_device.refcnt from atomic_t to refcount_t Date: Wed, 28 Jun 2017 14:54:59 +0300 Message-ID: <1498650906-12907-11-git-send-email-elena.reshetova@intel.com> References: <1498650906-12907-1-git-send-email-elena.reshetova@intel.com> Cc: bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kuznet@ms2.inr.ac.ru, jmorris@namei.org, kaber@trash.net, stephen@networkplumber.org, peterz@infradead.org, keescook@chromium.org, Elena Reshetova , Hans Liljestrand , David Windsor To: netdev@vger.kernel.org Return-path: Received: from mga14.intel.com ([192.55.52.115]:5509 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751943AbdF1Lz6 (ORCPT ); Wed, 28 Jun 2017 07:55:58 -0400 In-Reply-To: <1498650906-12907-1-git-send-email-elena.reshetova@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- include/linux/inetdevice.h | 11 ++++++----- net/ipv4/devinet.c | 2 +- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h index a2e9d6e..4b9d135 100644 --- a/include/linux/inetdevice.h +++ b/include/linux/inetdevice.h @@ -11,6 +11,7 @@ #include #include #include +#include struct ipv4_devconf { void *sysctl; @@ -22,7 +23,7 @@ struct ipv4_devconf { struct in_device { struct net_device *dev; - atomic_t refcnt; + refcount_t refcnt; int dead; struct in_ifaddr *ifa_list; /* IP ifaddr chain */ @@ -212,7 +213,7 @@ static inline struct in_device *in_dev_get(const struct net_device *dev) rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (in_dev) - atomic_inc(&in_dev->refcnt); + refcount_inc(&in_dev->refcnt); rcu_read_unlock(); return in_dev; } @@ -233,12 +234,12 @@ void in_dev_finish_destroy(struct in_device *idev); static inline void in_dev_put(struct in_device *idev) { - if (atomic_dec_and_test(&idev->refcnt)) + if (refcount_dec_and_test(&idev->refcnt)) in_dev_finish_destroy(idev); } -#define __in_dev_put(idev) atomic_dec(&(idev)->refcnt) -#define in_dev_hold(idev) atomic_inc(&(idev)->refcnt) +#define __in_dev_put(idev) refcount_dec(&(idev)->refcnt) +#define in_dev_hold(idev) refcount_inc(&(idev)->refcnt) #endif /* __KERNEL__ */ diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index df14815..16c5e22 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -251,7 +251,7 @@ static struct in_device *inetdev_init(struct net_device *dev) /* Reference in_dev->dev */ dev_hold(dev); /* Account for reference dev->ip_ptr (below) */ - in_dev_hold(in_dev); + refcount_set(&in_dev->refcnt, 1); err = devinet_sysctl_register(in_dev); if (err) { -- 2.7.4