From mboxrd@z Thu Jan 1 00:00:00 1970 From: Elena Reshetova Date: Tue, 28 Mar 2017 08:56:41 +0000 Subject: [PATCH 14/16] drivers, net, ppp: convert syncppp.refcnt from atomic_t to refcount_t Message-Id: <1490691403-4016-15-git-send-email-elena.reshetova@intel.com> List-Id: References: <1490691403-4016-1-git-send-email-elena.reshetova@intel.com> In-Reply-To: <1490691403-4016-1-git-send-email-elena.reshetova@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Cc: peterz@infradead.org, matanb@mellanox.com, paulus@samba.org, Elena Reshetova , nbd@openwrt.org, linux-rdma@vger.kernel.org, saeedm@mellanox.com, ganeshgr@chelsio.com, Hans Liljestrand , David Windsor , keescook@chromium.org, j@w1.fi, ajk@comnets.uni-bremen.de, leonro@mellanox.com, matthias.bgg@gmail.com, linux-hams@vger.kernel.org, kvalo@codeaurora.org, blogic@openwrt.org, linux-arm-kernel@lists.infradead.org, linux-ppp@vger.kernel.org, yishaih@mellanox.com, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org 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 --- drivers/net/ppp/ppp_synctty.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c index 9ae5398..4a643f8 100644 --- a/drivers/net/ppp/ppp_synctty.c +++ b/drivers/net/ppp/ppp_synctty.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -72,7 +73,7 @@ struct syncppp { struct tasklet_struct tsk; - atomic_t refcnt; + refcount_t refcnt; struct completion dead_cmp; struct ppp_channel chan; /* interface to generic ppp layer */ }; @@ -141,14 +142,14 @@ static struct syncppp *sp_get(struct tty_struct *tty) read_lock(&disc_data_lock); ap = tty->disc_data; if (ap != NULL) - atomic_inc(&ap->refcnt); + refcount_inc(&ap->refcnt); read_unlock(&disc_data_lock); return ap; } static void sp_put(struct syncppp *ap) { - if (atomic_dec_and_test(&ap->refcnt)) + if (refcount_dec_and_test(&ap->refcnt)) complete(&ap->dead_cmp); } @@ -182,7 +183,7 @@ ppp_sync_open(struct tty_struct *tty) skb_queue_head_init(&ap->rqueue); tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); - atomic_set(&ap->refcnt, 1); + refcount_set(&ap->refcnt, 1); init_completion(&ap->dead_cmp); ap->chan.private = ap; @@ -232,7 +233,7 @@ ppp_sync_close(struct tty_struct *tty) * our channel ops (i.e. ppp_sync_send/ioctl) are in progress * by the time it returns. */ - if (!atomic_dec_and_test(&ap->refcnt)) + if (!refcount_dec_and_test(&ap->refcnt)) wait_for_completion(&ap->dead_cmp); tasklet_kill(&ap->tsk); -- 2.7.4