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 13/15] drivers, net, ppp: convert ppp_file.refcnt from atomic_t to refcount_t
Date: Fri, 20 Oct 2017 07:23:47 +0000 [thread overview]
Message-ID: <1508484229-19706-14-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 ppp_file.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_generic.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index e365866..6566107 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -51,6 +51,7 @@
#include <asm/unaligned.h>
#include <net/slhc_vj.h>
#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
@@ -84,7 +85,7 @@ struct ppp_file {
struct sk_buff_head xq; /* pppd transmit queue */
struct sk_buff_head rq; /* receive queue for pppd */
wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
- atomic_t refcnt; /* # refs (incl /dev/ppp attached) */
+ refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
int hdrlen; /* space to leave for headers */
int index; /* interface unit / channel number */
int dead; /* unit/channel has been shut down */
@@ -408,7 +409,7 @@ static int ppp_release(struct inode *unused, struct file *file)
unregister_netdevice(ppp->dev);
rtnl_unlock();
}
- if (atomic_dec_and_test(&pf->refcnt)) {
+ if (refcount_dec_and_test(&pf->refcnt)) {
switch (pf->kind) {
case INTERFACE:
ppp_destroy_interface(PF_TO_PPP(pf));
@@ -881,7 +882,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
mutex_lock(&pn->all_ppp_mutex);
ppp = ppp_find_unit(pn, unit);
if (ppp) {
- atomic_inc(&ppp->file.refcnt);
+ refcount_inc(&ppp->file.refcnt);
file->private_data = &ppp->file;
err = 0;
}
@@ -896,7 +897,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
spin_lock_bh(&pn->all_channels_lock);
chan = ppp_find_channel(pn, unit);
if (chan) {
- atomic_inc(&chan->file.refcnt);
+ refcount_inc(&chan->file.refcnt);
file->private_data = &chan->file;
err = 0;
}
@@ -1348,7 +1349,7 @@ static int ppp_dev_init(struct net_device *dev)
* that ppp_destroy_interface() won't run before the device gets
* unregistered.
*/
- atomic_inc(&ppp->file.refcnt);
+ refcount_inc(&ppp->file.refcnt);
return 0;
}
@@ -1377,7 +1378,7 @@ static void ppp_dev_priv_destructor(struct net_device *dev)
struct ppp *ppp;
ppp = netdev_priv(dev);
- if (atomic_dec_and_test(&ppp->file.refcnt))
+ if (refcount_dec_and_test(&ppp->file.refcnt))
ppp_destroy_interface(ppp);
}
@@ -2676,7 +2677,7 @@ ppp_unregister_channel(struct ppp_channel *chan)
pch->file.dead = 1;
wake_up_interruptible(&pch->file.rwait);
- if (atomic_dec_and_test(&pch->file.refcnt))
+ if (refcount_dec_and_test(&pch->file.refcnt))
ppp_destroy_channel(pch);
}
@@ -3046,7 +3047,7 @@ init_ppp_file(struct ppp_file *pf, int kind)
pf->kind = kind;
skb_queue_head_init(&pf->xq);
skb_queue_head_init(&pf->rq);
- atomic_set(&pf->refcnt, 1);
+ refcount_set(&pf->refcnt, 1);
init_waitqueue_head(&pf->rwait);
}
@@ -3164,7 +3165,7 @@ ppp_connect_channel(struct channel *pch, int unit)
list_add_tail(&pch->clist, &ppp->channels);
++ppp->n_channels;
pch->ppp = ppp;
- atomic_inc(&ppp->file.refcnt);
+ refcount_inc(&ppp->file.refcnt);
ppp_unlock(ppp);
ret = 0;
@@ -3195,7 +3196,7 @@ ppp_disconnect_channel(struct channel *pch)
if (--ppp->n_channels = 0)
wake_up_interruptible(&ppp->file.rwait);
ppp_unlock(ppp);
- if (atomic_dec_and_test(&ppp->file.refcnt))
+ if (refcount_dec_and_test(&ppp->file.refcnt))
ppp_destroy_interface(ppp);
err = 0;
}
--
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 ` [PATCH 12/15] drivers, net, ppp: convert asyncppp.refcnt " Elena Reshetova
2017-10-20 7:23 ` Elena Reshetova [this message]
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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