[3.11.y.z extended stable] Patch "core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle errors" has been added to staging queue

[Luis Henriques]

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

    core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle errors

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From dcf5c994af851fa224b8af91929eefb3e128c1ca Mon Sep 17 00:00:00 2001
From: Zoltan Kiss <zoltan.kiss at citrix.com>
Date: Wed, 26 Mar 2014 22:37:45 +0000
Subject: core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle
 errors

commit 36d5fe6a000790f56039afe26834265db0a3ad4c upstream.

skb_zerocopy can copy elements of the frags array between skbs, but it doesn't
orphan them. Also, it doesn't handle errors, so this patch takes care of that
as well, and modify the callers accordingly. skb_tx_error() is also added to
the callers so they will signal the failed delivery towards the creator of the
skb.

Signed-off-by: Zoltan Kiss <zoltan.kiss at citrix.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Josh Boyer <jwboyer at fedoraproject.org>
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
[ luis: backported to 3.11: used 3.13 backport from Josh and Ben ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/netfilter/nfnetlink_queue_core.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index 8a703c3..39e8935 100644
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -235,22 +235,23 @@ nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data)
 	spin_unlock_bh(&queue->lock);
 }

-static void
-nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
+static int
+nfqnl_zcopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 {
 	int i, j = 0;
 	int plen = 0; /* length of skb->head fragment */
+	int ret;
 	struct page *page;
 	unsigned int offset;

 	/* dont bother with small payloads */
-	if (len <= skb_tailroom(to)) {
-		skb_copy_bits(from, 0, skb_put(to, len), len);
-		return;
-	}
+	if (len <= skb_tailroom(to))
+		return skb_copy_bits(from, 0, skb_put(to, len), len);

 	if (hlen) {
-		skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+		ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+		if (unlikely(ret))
+			return ret;
 		len -= hlen;
 	} else {
 		plen = min_t(int, skb_headlen(from), len);
@@ -268,6 +269,11 @@ nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
 	to->len += len + plen;
 	to->data_len += len + plen;

+	if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
+		skb_tx_error(from);
+		return -ENOMEM;
+	}
+
 	for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
 		if (!len)
 			break;
@@ -278,6 +284,8 @@ nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
 		j++;
 	}
 	skb_shinfo(to)->nr_frags = j;
+
+	return 0;
 }

 static int
@@ -374,13 +382,16 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,

 	skb = nfnetlink_alloc_skb(&init_net, size, queue->peer_portid,
 				  GFP_ATOMIC);
-	if (!skb)
+	if (!skb) {
+		skb_tx_error(entskb);
 		return NULL;
+	}

 	nlh = nlmsg_put(skb, 0, 0,
 			NFNL_SUBSYS_QUEUE << 8 | NFQNL_MSG_PACKET,
 			sizeof(struct nfgenmsg), 0);
 	if (!nlh) {
+		skb_tx_error(entskb);
 		kfree_skb(skb);
 		return NULL;
 	}
@@ -504,13 +515,15 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
 		nla->nla_type = NFQA_PAYLOAD;
 		nla->nla_len = nla_attr_size(data_len);

-		nfqnl_zcopy(skb, entskb, data_len, hlen);
+		if (nfqnl_zcopy(skb, entskb, data_len, hlen))
+			goto nla_put_failure;
 	}

 	nlh->nlmsg_len = skb->len;
 	return skb;

 nla_put_failure:
+	skb_tx_error(entskb);
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 	return NULL;
--
1.9.1