mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-12-10 16:34:22 -05:00
56 lines
1.9 KiB
Diff
56 lines
1.9 KiB
Diff
From 205e1e255c479f3fd77446415706463b282f94e4 Mon Sep 17 00:00:00 2001
|
|
From: WANG Cong <xiyou.wangcong@gmail.com>
|
|
Date: Tue, 5 Jul 2016 22:12:36 -0700
|
|
Subject: ppp: defer netns reference release for ppp channel
|
|
|
|
Matt reported that we have a NULL pointer dereference
|
|
in ppp_pernet() from ppp_connect_channel(),
|
|
i.e. pch->chan_net is NULL.
|
|
|
|
This is due to that a parallel ppp_unregister_channel()
|
|
could happen while we are in ppp_connect_channel(), during
|
|
which pch->chan_net set to NULL. Since we need a reference
|
|
to net per channel, it makes sense to sync the refcnt
|
|
with the life time of the channel, therefore we should
|
|
release this reference when we destroy it.
|
|
|
|
Fixes: 1f461dcdd296 ("ppp: take reference on channels netns")
|
|
Reported-by: Matt Bennett <Matt.Bennett@alliedtelesis.co.nz>
|
|
Cc: Paul Mackerras <paulus@samba.org>
|
|
Cc: linux-ppp@vger.kernel.org
|
|
Cc: Guillaume Nault <g.nault@alphalink.fr>
|
|
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
|
|
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
|
|
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
---
|
|
drivers/net/ppp/ppp_generic.c | 5 +++--
|
|
1 file changed, 3 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
|
|
index 8dedafa..a30ee42 100644
|
|
--- a/drivers/net/ppp/ppp_generic.c
|
|
+++ b/drivers/net/ppp/ppp_generic.c
|
|
@@ -2601,8 +2601,6 @@ ppp_unregister_channel(struct ppp_channel *chan)
|
|
spin_lock_bh(&pn->all_channels_lock);
|
|
list_del(&pch->list);
|
|
spin_unlock_bh(&pn->all_channels_lock);
|
|
- put_net(pch->chan_net);
|
|
- pch->chan_net = NULL;
|
|
|
|
pch->file.dead = 1;
|
|
wake_up_interruptible(&pch->file.rwait);
|
|
@@ -3136,6 +3134,9 @@ ppp_disconnect_channel(struct channel *pch)
|
|
*/
|
|
static void ppp_destroy_channel(struct channel *pch)
|
|
{
|
|
+ put_net(pch->chan_net);
|
|
+ pch->chan_net = NULL;
|
|
+
|
|
atomic_dec(&channel_count);
|
|
|
|
if (!pch->file.dead) {
|
|
--
|
|
cgit v1.1
|
|
|