Patch "netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()

to the 3.14-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:
netfilter-zero-the-tuple-in-nfnl_cthelper_parse_tuple.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ian Wilson <[email protected]>
Date: Thu, 12 Mar 2015 09:37:58 +0000
Subject: netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()

From: Ian Wilson <[email protected]>

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.

---
 net/netfilter/nfnetlink_cthelper.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -77,6 +77,9 @@ nfnl_cthelper_parse_tuple(struct nf_conn
 	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]);
 

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/netfilter-zero-the-tuple-in-nfnl_cthelper_parse_tuple.patch