Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorWANG Cong <xiyou.wangcong@gmail.com>2016-07-05 22:12:36 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-06 11:16:17 +0100
commit7a2b4ee54b3f23668fa366a4b0e04d351f809bb0 (patch)
tree8d7d84a5a9abc7ec5bcaf89337917895247b9573
parent37de955c11b59050346e530143c20b10b4846527 (diff)
ppp: defer netns reference release for ppp channel
commit 205e1e255c479f3fd77446415706463b282f94e4 upstream. 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> Cc: bmajal222 <bmajal222@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/ppp/ppp_generic.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 174e06ec7c2f..e5bb870b5461 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -2390,8 +2390,6 @@ 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);
@@ -2984,6 +2982,9 @@ 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) {