net, atm: convert atm_dev.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 <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 2017-07-04 15:53:01 +03:00 committed by David S. Miller
parent e0542dd518
commit 458bc30cec
3 changed files with 6 additions and 5 deletions

View File

@ -11,6 +11,7 @@
#include <linux/uio.h>
#include <net/sock.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <uapi/linux/atmdev.h>
#ifdef CONFIG_PROC_FS
@ -158,7 +159,7 @@ struct atm_dev {
struct k_atm_dev_stats stats; /* statistics */
char signal; /* signal status (ATM_PHY_SIG_*) */
int link_rate; /* link rate (default: OC3) */
atomic_t refcnt; /* reference count */
refcount_t refcnt; /* reference count */
spinlock_t lock; /* protect internal members */
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *proc_entry; /* proc entry */
@ -261,13 +262,13 @@ static inline int atm_may_send(struct atm_vcc *vcc,unsigned int size)
static inline void atm_dev_hold(struct atm_dev *dev)
{
atomic_inc(&dev->refcnt);
refcount_inc(&dev->refcnt);
}
static inline void atm_dev_put(struct atm_dev *dev)
{
if (atomic_dec_and_test(&dev->refcnt)) {
if (refcount_dec_and_test(&dev->refcnt)) {
BUG_ON(!test_bit(ATM_DF_REMOVED, &dev->flags));
if (dev->ops->dev_close)
dev->ops->dev_close(dev);

View File

@ -61,7 +61,7 @@ static void atm_dev_info(struct seq_file *seq, const struct atm_dev *dev)
add_stats(seq, "0", &dev->stats.aal0);
seq_puts(seq, " ");
add_stats(seq, "5", &dev->stats.aal5);
seq_printf(seq, "\t[%d]", atomic_read(&dev->refcnt));
seq_printf(seq, "\t[%d]", refcount_read(&dev->refcnt));
seq_putc(seq, '\n');
}

View File

@ -109,7 +109,7 @@ struct atm_dev *atm_dev_register(const char *type, struct device *parent,
else
memset(&dev->flags, 0, sizeof(dev->flags));
memset(&dev->stats, 0, sizeof(dev->stats));
atomic_set(&dev->refcnt, 1);
refcount_set(&dev->refcnt, 1);
if (atm_proc_dev_register(dev) < 0) {
pr_err("atm_proc_dev_register failed for dev %s\n", type);