[3.16.y-ckt stable] Patch "netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 9aa16680903ed6a4786ddb2f1519fa5726d41918 Mon Sep 17 00:00:00 2001
From: Ian Wilson <iwilson at brocade.com>
Date: Thu, 12 Mar 2015 09:37:58 +0000
Subject: netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()

commit 78146572b9cd20452da47951812f35b1ad4906be upstream.

nfnl_cthelper_parse_tuple() is called from nfnl_cthelper_new(),
nfnl_cthelper_get() and nfnl_cthelper_del().  In each case they pass
a pointer to an nf_conntrack_tuple data structure local variable:

    struct nf_conntrack_tuple tuple;
    ...
    ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);

The problem is that this local variable is not initialized, and
nfnl_cthelper_parse_tuple() only initializes two fields: src.l3num and
dst.protonum.  This leaves all other fields with undefined values
based on whatever is on the stack:

    tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
    tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);

The symptom observed was that when the rpc and tns helpers were added
then traffic to port 1536 was being sent to user-space.

Signed-off-by: Ian Wilson <iwilson at brocade.com>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/netfilter/nfnetlink_cthelper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c
index 9e287cb56a04..7f035f0772ee 100644
--- a/net/netfilter/nfnetlink_cthelper.c
+++ b/net/netfilter/nfnetlink_cthelper.c
@@ -77,6 +77,9 @@ nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
 	if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
 		return -EINVAL;

+	/* Not all fields are initialized so first zero the tuple */
+	memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
+
 	tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
 	tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);