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Bluetooth: convert rfcomm_dlc.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: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Elena Reshetova 2017-03-17 13:12:46 +02:00 committed by Marcel Holtmann
parent 9232259913
commit dab6b5daee
2 changed files with 7 additions and 5 deletions
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8
include/net/bluetooth/rfcomm.h
View File

@ -21,6 +21,8 @@
SOFTWARE IS DISCLAIMED.
*/
#include <linux/refcount.h>
#ifndef __RFCOMM_H
#define __RFCOMM_H
@ -174,7 +176,7 @@ struct rfcomm_dlc {
struct mutex lock;
unsigned long state;
unsigned long flags;
atomic_t refcnt;
refcount_t refcnt;
u8 dlci;
u8 addr;
u8 priority;
@ -247,12 +249,12 @@ struct rfcomm_dlc *rfcomm_dlc_exists(bdaddr_t *src, bdaddr_t *dst, u8 channel);
static inline void rfcomm_dlc_hold(struct rfcomm_dlc *d)
{
atomic_inc(&d->refcnt);
refcount_inc(&d->refcnt);
}
static inline void rfcomm_dlc_put(struct rfcomm_dlc *d)
{
if (atomic_dec_and_test(&d->refcnt))
if (refcount_dec_and_test(&d->refcnt))
rfcomm_dlc_free(d);
}

4
net/bluetooth/rfcomm/core.c
View File

@ -311,7 +311,7 @@ struct rfcomm_dlc *rfcomm_dlc_alloc(gfp_t prio)
skb_queue_head_init(&d->tx_queue);
mutex_init(&d->lock);
atomic_set(&d->refcnt, 1);
refcount_set(&d->refcnt, 1);
rfcomm_dlc_clear_state(d);
@ -342,7 +342,7 @@ static void rfcomm_dlc_unlink(struct rfcomm_dlc *d)
{
struct rfcomm_session *s = d->session;
BT_DBG("dlc %p refcnt %d session %p", d, atomic_read(&d->refcnt), s);
BT_DBG("dlc %p refcnt %d session %p", d, refcount_read(&d->refcnt), s);
list_del(&d->list);
d->session = NULL;