From 7658b36f1b3122c298213eed344f622e836b281b Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Fri, 30 Jun 2017 13:08:03 +0300 Subject: [PATCH] net: convert in_device.refcnt from atomic_t to refcount_t 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 Signed-off-by: David S. Miller --- 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 e7c04c4..fb3f809 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 */ @@ -219,7 +220,7 @@ 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; } @@ -240,12 +241,12 @@ 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 a7dd088..38d9af9 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -252,7 +252,7 @@ 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