This is a note to let you know that I've just added the patch titled
sit: fix use after free of fb_tunnel_dev
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sit-fix-use-after-free-of-fb_tunnel_dev.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Dec 5 16:16:39 PST 2013
From: Willem de Bruijn <willemb@xxxxxxxxxx>
Date: Wed, 13 Nov 2013 21:27:38 -0500
Subject: sit: fix use after free of fb_tunnel_dev
From: Willem de Bruijn <willemb@xxxxxxxxxx>
[ Upstream commit 9434266f2c645d4fcf62a03a8e36ad8075e37943 ]
Bug: The fallback device is created in sit_init_net and assumed to be
freed in sit_exit_net. First, it is dereferenced in that function, in
sit_destroy_tunnels:
struct net *net = dev_net(sitn->fb_tunnel_dev);
Prior to this, rtnl_unlink_register has removed all devices that match
rtnl_link_ops == sit_link_ops.
Commit 205983c43700 added the line
+ sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
which cases the fallback device to match here and be freed before it
is last dereferenced.
Fix: This commit adds an explicit .delllink callback to sit_link_ops
that skips deallocation at rtnl_unlink_register for the fallback
device. This mechanism is comparable to the one in ip_tunnel.
It also modifies sit_destroy_tunnels and its only caller sit_exit_net
to avoid the offending dereference in the first place. That double
lookup is more complicated than required.
Test: The bug is only triggered when CONFIG_NET_NS is enabled. It
causes a GPF only when CONFIG_DEBUG_SLAB is enabled. Verified that
this bug exists at the mentioned commit, at davem-net HEAD and at
3.11.y HEAD. Verified that it went away after applying this patch.
Fixes: 205983c43700 ("sit: allow to use rtnl ops on fb tunnel")
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Acked-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/sit.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1594,6 +1594,15 @@ static const struct nla_policy ipip6_pol
#endif
};
+static void ipip6_dellink(struct net_device *dev, struct list_head *head)
+{
+ struct net *net = dev_net(dev);
+ struct sit_net *sitn = net_generic(net, sit_net_id);
+
+ if (dev != sitn->fb_tunnel_dev)
+ unregister_netdevice_queue(dev, head);
+}
+
static struct rtnl_link_ops sit_link_ops __read_mostly = {
.kind = "sit",
.maxtype = IFLA_IPTUN_MAX,
@@ -1605,6 +1614,7 @@ static struct rtnl_link_ops sit_link_ops
.changelink = ipip6_changelink,
.get_size = ipip6_get_size,
.fill_info = ipip6_fill_info,
+ .dellink = ipip6_dellink,
};
static struct xfrm_tunnel sit_handler __read_mostly = {
@@ -1619,9 +1629,10 @@ static struct xfrm_tunnel ipip_handler _
.priority = 2,
};
-static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
+static void __net_exit sit_destroy_tunnels(struct net *net,
+ struct list_head *head)
{
- struct net *net = dev_net(sitn->fb_tunnel_dev);
+ struct sit_net *sitn = net_generic(net, sit_net_id);
struct net_device *dev, *aux;
int prio;
@@ -1696,11 +1707,10 @@ err_alloc_dev:
static void __net_exit sit_exit_net(struct net *net)
{
- struct sit_net *sitn = net_generic(net, sit_net_id);
LIST_HEAD(list);
rtnl_lock();
- sit_destroy_tunnels(sitn, &list);
+ sit_destroy_tunnels(net, &list);
unregister_netdevice_many(&list);
rtnl_unlock();
}
Patches currently in stable-queue which might be from willemb@xxxxxxxxxx are
queue-3.12/pkt_sched-fq-fix-pacing-for-small-frames.patch
queue-3.12/sit-fix-use-after-free-of-fb_tunnel_dev.patch
queue-3.12/af_packet-block-bh-in-prb_shutdown_retire_blk_timer.patch
queue-3.12/pkt_sched-fq-change-classification-of-control.patch
queue-3.12/ip6tnl-fix-use-after-free-of-fb_tnl_dev.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html