This is a note to let you know that I've just added the patch titled
net: sched: fix NULL pointer dereference when action calls some targets
to the 4.4-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:
net-sched-fix-null-pointer-dereference-when-action-calls-some-targets.patch
and it can be found in the queue-4.4 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 Aug 24 17:48:38 PDT 2017
From: Xin Long <lucien.xin@xxxxxxxxx>
Date: Fri, 18 Aug 2017 11:01:36 +0800
Subject: net: sched: fix NULL pointer dereference when action calls some targets
From: Xin Long <lucien.xin@xxxxxxxxx>
[ Upstream commit 4f8a881acc9d1adaf1e552349a0b1df28933a04c ]
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.
Note that this issue has been there since the very beginning.
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sched/act_ipt.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -34,6 +34,7 @@ static int ipt_init_target(struct xt_ent
{
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,
@@ -44,6 +45,7 @@ static int ipt_init_target(struct xt_ent
t->u.kernel.target = target;
memset(&par, 0, sizeof(par));
par.table = table;
+ par.entryinfo = &e;
par.target = target;
par.targinfo = t->data;
par.hook_mask = hook;
Patches currently in stable-queue which might be from lucien.xin@xxxxxxxxx are
queue-4.4/net-sched-fix-null-pointer-dereference-when-action-calls-some-targets.patch
queue-4.4/sctp-fully-initialize-the-ipv6-address-in-sctp_v6_to_addr.patch