As we know in some target's checkentry it may dereference par.entryinfo
to check entry stuff inside. But when sched action calls xt_check_target,
par.entryinfo is set with NULL. It would cause kernel panic when calling
some targets.
It can be reproduce with:
# tc qd add dev eth1 ingress handle ffff:
# tc filter add dev eth1 parent ffff: u32 match u32 0 0 action xt \
-j ECN --ecn-tcp-remove
It could also crash kernel when using target CLUSTERIP or TPROXY.
By now there's no proper value for par.entryinfo in ipt_init_target,
but it can not be set with NULL. This patch is to void all these
panics by setting it with an ipt_entry obj with all members 0.
Signed-off-by: Xin Long <lucien....@gmail.com>
---
net/sched/act_ipt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 7c4816b..0f09f70 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -41,6 +41,7 @@ static int ipt_init_target(struct net *net, struct
xt_entry_target *t,
{
struct xt_tgchk_param par;
struct xt_target *target;
+ struct ipt_entry e;
int ret = 0;
target = xt_request_find_target(AF_INET, t->u.user.name,
@@ -48,10 +49,11 @@ static int ipt_init_target(struct net *net, struct
xt_entry_target *t,
if (IS_ERR(target))
return PTR_ERR(target);
+ memset(&e, 0, sizeof(e));
t->u.kernel.target = target;
par.net = net;
par.table = table;
- par.entryinfo = NULL;
+ par.entryinfo = &e;
par.target = target;
par.targinfo = t->data;
par.hook_mask = hook;
--
2.1.0
