From: Elena Reshetova <elena.reshetova@intel.com>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-rdma@vger.kernel.org,
linux-hams@vger.kernel.org, linux-ppp@vger.kernel.org,
ganeshgr@chelsio.com, nbd@openwrt.org, john@phrozen.org,
sean.wang@mediatek.com, matthias.bgg@gmail.com,
yishaih@mellanox.com, saeedm@mellanox.com, matanb@mellanox.com,
tariqt@mellanox.com, leonro@mellanox.com,
ajk@comnets.uni-bremen.de, paulus@samba.org, zbr@ioremap.net,
peterz@infradead.org, keescook@chromium.org,
Elena Reshetova <elena.reshetova@intel.com>
Subject: [PATCH 12/15] drivers, net, ppp: convert asyncppp.refcnt from atomic_t to refcount_t
Date: Fri, 20 Oct 2017 07:23:46 +0000 [thread overview]
Message-ID: <1508484229-19706-13-git-send-email-elena.reshetova@intel.com> (raw)
In-Reply-To: <1508484229-19706-1-git-send-email-elena.reshetova@intel.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable asyncppp.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
---
drivers/net/ppp/ppp_async.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ppp/ppp_async.c b/drivers/net/ppp/ppp_async.c
index 814fd8f..1b28e6e 100644
--- a/drivers/net/ppp/ppp_async.c
+++ b/drivers/net/ppp/ppp_async.c
@@ -69,7 +69,7 @@ struct asyncppp {
struct tasklet_struct tsk;
- atomic_t refcnt;
+ refcount_t refcnt;
struct semaphore dead_sem;
struct ppp_channel chan; /* interface to generic ppp layer */
unsigned char obuf[OBUFSIZE];
@@ -140,14 +140,14 @@ static struct asyncppp *ap_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 ap_put(struct asyncppp *ap)
{
- if (atomic_dec_and_test(&ap->refcnt))
+ if (refcount_dec_and_test(&ap->refcnt))
up(&ap->dead_sem);
}
@@ -185,7 +185,7 @@ ppp_asynctty_open(struct tty_struct *tty)
skb_queue_head_init(&ap->rqueue);
tasklet_init(&ap->tsk, ppp_async_process, (unsigned long) ap);
- atomic_set(&ap->refcnt, 1);
+ refcount_set(&ap->refcnt, 1);
sema_init(&ap->dead_sem, 0);
ap->chan.private = ap;
@@ -234,7 +234,7 @@ ppp_asynctty_close(struct tty_struct *tty)
* our channel ops (i.e. ppp_async_send/ioctl) are in progress
* by the time it returns.
*/
- if (!atomic_dec_and_test(&ap->refcnt))
+ if (!refcount_dec_and_test(&ap->refcnt))
down(&ap->dead_sem);
tasklet_kill(&ap->tsk);
--
2.7.4
next prev parent reply other threads:[~2017-10-20 7:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 7:23 [PATCH 00/15] networking drivers refcount_t conversions Elena Reshetova
2017-10-20 7:23 ` [PATCH 01/15] drivers, net, ethernet: convert clip_entry.refcnt from atomic_t to refcount_t Elena Reshetova
2017-10-20 7:23 ` [PATCH 02/15] drivers, net, ethernet: convert mtk_eth.dma_refcnt " Elena Reshetova
[not found] ` <1508484229-19706-3-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-10-20 8:08 ` Sean Wang
2017-10-20 10:37 ` Reshetova, Elena
2017-10-22 4:06 ` Sean Wang
2017-10-23 6:37 ` Reshetova, Elena
2017-10-20 7:23 ` [PATCH 03/15] drivers, net, mlx4: convert mlx4_cq.refcount " Elena Reshetova
[not found] ` <1508484229-19706-1-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-10-20 7:23 ` [PATCH 04/15] drivers, net, mlx4: convert mlx4_qp.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 05/15] drivers, net, mlx4: convert mlx4_srq.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 06/15] drivers, net, mlx5: convert mlx5_cq.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 07/15] drivers, net, mlx5: convert fs_node.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 08/15] drivers, net, hamradio: convert sixpack.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 09/15] drivers, net: convert masces_rx_sa.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 10/15] drivers, net: convert masces_rx_sc.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 11/15] drivers, net: convert masces_tx_sa.refcnt " Elena Reshetova
2017-10-20 7:23 ` Elena Reshetova [this message]
2017-10-20 7:23 ` [PATCH 13/15] drivers, net, ppp: convert ppp_file.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 14/15] drivers, net, ppp: convert syncppp.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 15/15] drivers, connector: convert cn_callback_entry.refcnt " Elena Reshetova
2017-10-22 1:31 ` [PATCH 00/15] networking drivers refcount_t conversions David Miller
2017-10-23 6:34 ` Reshetova, Elena
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