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net: convert in_device.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 13:08:03 +03:00 committed by David S. Miller
parent 8851ab5267
commit 7658b36f1b
2 changed files with 7 additions and 6 deletions
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11
include/linux/inetdevice.h
View file

@ -11,6 +11,7 @@
#include <linux/timer.h> #include <linux/timer.h>
#include <linux/sysctl.h> #include <linux/sysctl.h>
#include <linux/rtnetlink.h> #include <linux/rtnetlink.h>
#include <linux/refcount.h>
struct ipv4_devconf { struct ipv4_devconf {
void *sysctl; void *sysctl;
@ -22,7 +23,7 @@ struct ipv4_devconf {
struct in_device { struct in_device {
struct net_device *dev; struct net_device *dev;
atomic_t refcnt; refcount_t refcnt;
int dead; int dead;
struct in_ifaddr *ifa_list; /* IP ifaddr chain */ 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(); rcu_read_lock();
in_dev = __in_dev_get_rcu(dev); in_dev = __in_dev_get_rcu(dev);
if (in_dev) if (in_dev)
atomic_inc(&in_dev->refcnt); refcount_inc(&in_dev->refcnt);
rcu_read_unlock(); rcu_read_unlock();
return in_dev; 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) 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); in_dev_finish_destroy(idev);
} }
#define __in_dev_put(idev) atomic_dec(&(idev)->refcnt) #define __in_dev_put(idev) refcount_dec(&(idev)->refcnt)
#define in_dev_hold(idev) atomic_inc(&(idev)->refcnt) #define in_dev_hold(idev) refcount_inc(&(idev)->refcnt)
#endif /* __KERNEL__ */ #endif /* __KERNEL__ */

2
net/ipv4/devinet.c
View file

@ -252,7 +252,7 @@ static struct in_device *inetdev_init(struct net_device *dev)
/* Reference in_dev->dev */ /* Reference in_dev->dev */
dev_hold(dev); dev_hold(dev);
/* Account for reference dev->ip_ptr (below) */ /* Account for reference dev->ip_ptr (below) */
in_dev_hold(in_dev); refcount_set(&in_dev->refcnt, 1);
err = devinet_sysctl_register(in_dev); err = devinet_sysctl_register(in_dev);
if (err) { if (err) {