netdev - [PATCH 3.13.y] nfqueue: Orphan frags in nfqnl

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Message-ID: <20140328142914.GB25962@hansolo.jdub.homelinux.org>
Date:	Fri, 28 Mar 2014 10:29:14 -0400
From:	Josh Boyer <jwboyer@...oraproject.org>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	Zoltan Kiss <zoltan.kiss@...rix.com>, Thomas Graf <tgraf@...g.ch>,
	netdev@...r.kernel.org
Subject: [PATCH 3.13.y] nfqueue: Orphan frags in nfqnl_zcopy and handle errors

Backport of upstream commit 36d5fe6a0007 to 3.13.y

nfqnl_zcopy 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 caller accordingly.  skb_tx_error() is also added to
the callers so they will signal the failed delivery towards the creator of the
skb.

Fixes CVE-2014-2568.

Signed-off-by: Zoltan Kiss <zoltan.kiss@...rix.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Josh Boyer <jwboyer@...oraproject.org>
---
 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 21258cf..b241654 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 net *net, struct nfqnl_instance *queue,
 
 	skb = nfnetlink_alloc_skb(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 net *net, 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;
-- 
1.8.5.3

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