1 files changed, 27 insertions, 10 deletions

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 9b0158fa431f..867be8f7f1fa 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -346,10 +346,10 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
 	struct rb_node **rbn, *parent;
 	struct sk_buff *skb1, *prev_tail;
+	int ihl, end, skb1_run_end;
 	struct net_device *dev;
 	unsigned int fragsize;
 	int flags, offset;
-	int ihl, end;
 	int err = -ENOENT;
 	u8 ecn;
 
@@ -419,7 +419,9 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 	 *   overlapping fragment, the entire datagram (and any constituent
 	 *   fragments) MUST be silently discarded.
 	 *
-	 * We do the same here for IPv4 (and increment an snmp counter).
+	 * We do the same here for IPv4 (and increment an snmp counter) but
+	 * we do not want to drop the whole queue in response to a duplicate
+	 * fragment.
 	 */
 
 	err = -EINVAL;
@@ -444,13 +446,17 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
 		do {
 			parent = *rbn;
 			skb1 = rb_to_skb(parent);
+			skb1_run_end = skb1->ip_defrag_offset +
+				       FRAG_CB(skb1)->frag_run_len;
 			if (end <= skb1->ip_defrag_offset)
 				rbn = &parent->rb_left;
-			else if (offset >= skb1->ip_defrag_offset +
-						FRAG_CB(skb1)->frag_run_len)
+			else if (offset >= skb1_run_end)
 				rbn = &parent->rb_right;
-			else /* Found an overlap with skb1. */
-				goto overlap;
+			else if (offset >= skb1->ip_defrag_offset &&
+				 end <= skb1_run_end)
+				goto err; /* No new data, potential duplicate */
+			else
+				goto overlap; /* Found an overlap */
 		} while (*rbn);
 		/* Here we have parent properly set, and rbn pointing to
 		 * one of its NULL left/right children. Insert skb.
@@ -515,6 +521,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
 	struct rb_node *rbn;
 	int len;
 	int ihlen;
+	int delta;
 	int err;
 	u8 ecn;
 
@@ -556,10 +563,16 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
 	if (len > 65535)
 		goto out_oversize;
 
+	delta = - head->truesize;
+
 	/* Head of list must not be cloned. */
 	if (skb_unclone(head, GFP_ATOMIC))
 		goto out_nomem;
 
+	delta += head->truesize;
+	if (delta)
+		add_frag_mem_limit(qp->q.net, delta);
+
 	/* If the first fragment is fragmented itself, we split
 	 * it to two chunks: the first with data and paged part
 	 * and the second, holding only fragments. */
@@ -722,10 +735,14 @@ struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 	if (ip_is_fragment(&iph)) {
 		skb = skb_share_check(skb, GFP_ATOMIC);
 		if (skb) {
-			if (!pskb_may_pull(skb, netoff + iph.ihl * 4))
-				return skb;
-			if (pskb_trim_rcsum(skb, netoff + len))
-				return skb;
+			if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) {
+				kfree_skb(skb);
+				return NULL;
+			}
+			if (pskb_trim_rcsum(skb, netoff + len)) {
+				kfree_skb(skb);
+				return NULL;
+			}
 			memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
 			if (ip_defrag(net, skb, user))
 				return NULL;