[PATCH 4.12 08/17] net: sched: set xt_tgchk_param par.net properly in ipt_init_target

From: Greg Kroah-Hartman
Date: Fri Aug 11 2017 - 18:15:48 EST


4.12-stable review patch. If anyone has any objections, please let me know.

------------------

From: Xin Long <lucien.xin@xxxxxxxxx>


[ Upstream commit ec0acb09313074ba1a4976945791d9c6815f39fb ]

Now xt_tgchk_param par in ipt_init_target is a local varibale,
par.net is not initialized there. Later when xt_check_target
calls target's checkentry in which it may access par.net, it
would cause kernel panic.

Jaroslav found this panic when running:

# ip link add TestIface type dummy
# tc qd add dev TestIface ingress handle ffff:
# tc filter add dev TestIface parent ffff: u32 match u32 0 0 \
action xt -j CONNMARK --set-mark 4

This patch is to pass net param into ipt_init_target and set
par.net with it properly in there.

v1->v2:
As Wang Cong pointed, I missed ipt_net_id != xt_net_id, so fix
it by also passing net_id to __tcf_ipt_init.
v2->v3:
Missed the fixes tag, so add it.

Fixes: ecb2421b5ddf ("netfilter: add and use nf_ct_netns_get/put")
Reported-by: Jaroslav Aster <jaster@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sched/act_ipt.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -36,8 +36,8 @@ static struct tc_action_ops act_ipt_ops;
static unsigned int xt_net_id;
static struct tc_action_ops act_xt_ops;

-static int ipt_init_target(struct xt_entry_target *t, char *table,
- unsigned int hook)
+static int ipt_init_target(struct net *net, struct xt_entry_target *t,
+ char *table, unsigned int hook)
{
struct xt_tgchk_param par;
struct xt_target *target;
@@ -49,6 +49,7 @@ static int ipt_init_target(struct xt_ent
return PTR_ERR(target);

t->u.kernel.target = target;
+ par.net = net;
par.table = table;
par.entryinfo = NULL;
par.target = target;
@@ -91,10 +92,11 @@ static const struct nla_policy ipt_polic
[TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) },
};

-static int __tcf_ipt_init(struct tc_action_net *tn, struct nlattr *nla,
+static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
struct nlattr *est, struct tc_action **a,
const struct tc_action_ops *ops, int ovr, int bind)
{
+ struct tc_action_net *tn = net_generic(net, id);
struct nlattr *tb[TCA_IPT_MAX + 1];
struct tcf_ipt *ipt;
struct xt_entry_target *td, *t;
@@ -159,7 +161,7 @@ static int __tcf_ipt_init(struct tc_acti
if (unlikely(!t))
goto err2;

- err = ipt_init_target(t, tname, hook);
+ err = ipt_init_target(net, t, tname, hook);
if (err < 0)
goto err3;

@@ -193,18 +195,16 @@ static int tcf_ipt_init(struct net *net,
struct nlattr *est, struct tc_action **a, int ovr,
int bind)
{
- struct tc_action_net *tn = net_generic(net, ipt_net_id);
-
- return __tcf_ipt_init(tn, nla, est, a, &act_ipt_ops, ovr, bind);
+ return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
+ bind);
}

static int tcf_xt_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a, int ovr,
int bind)
{
- struct tc_action_net *tn = net_generic(net, xt_net_id);
-
- return __tcf_ipt_init(tn, nla, est, a, &act_xt_ops, ovr, bind);
+ return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
+ bind);
}

static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,