4 files changed, 31 insertions, 19 deletions

diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 245ae078a07f..f4fd23de9b13 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -21,6 +21,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/slab.h>
 
+#include <net/sock.h>
 #include <net/inet_frag.h>
 
 static void inet_frag_secret_rebuild(unsigned long dummy)
@@ -277,6 +278,7 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
 	__releases(&f->lock)
 {
 	struct inet_frag_queue *q;
+	int depth = 0;
 
 	hlist_for_each_entry(q, &f->hash[hash], list) {
 		if (q->net == nf && f->match(q, key)) {
@@ -284,9 +286,25 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
 			read_unlock(&f->lock);
 			return q;
 		}
+		depth++;
 	}
 	read_unlock(&f->lock);
 
-	return inet_frag_create(nf, f, key);
+	if (depth <= INETFRAGS_MAXDEPTH)
+		return inet_frag_create(nf, f, key);
+	else
+		return ERR_PTR(-ENOBUFS);
 }
 EXPORT_SYMBOL(inet_frag_find);
+
+void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
+				   const char *prefix)
+{
+	static const char msg[] = "inet_frag_find: Fragment hash bucket"
+		" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
+		". Dropping fragment.\n";
+
+	if (PTR_ERR(q) == -ENOBUFS)
+		LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
+}
+EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index b6d30acb600c..a6445b843ef4 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -292,14 +292,11 @@ static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user)
 	hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol);
 
 	q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash);
-	if (q == NULL)
-		goto out_nomem;
-
+	if (IS_ERR_OR_NULL(q)) {
+		inet_frag_maybe_warn_overflow(q, pr_fmt());
+		return NULL;
+	}
 	return container_of(q, struct ipq, q);
-
-out_nomem:
-	LIMIT_NETDEBUG(KERN_ERR pr_fmt("ip_frag_create: no memory left !\n"));
-	return NULL;
 }
 
 /* Is the fragment too far ahead to be part of ipq? */
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d0ef0e674ec5..91d66dbde9c0 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -798,10 +798,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 
 	if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
 		gre_hlen = 0;
-		if (skb->protocol == htons(ETH_P_IP))
-			tiph = (const struct iphdr *)skb->data;
-		else
-			tiph = &tunnel->parms.iph;
+		tiph = (const struct iphdr *)skb->data;
 	} else {
 		gre_hlen = tunnel->hlen;
 		tiph = &tunnel->parms.iph;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4a8ec457310f..d09203c63264 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -274,13 +274,6 @@ static void tcp_v4_mtu_reduced(struct sock *sk)
 	struct inet_sock *inet = inet_sk(sk);
 	u32 mtu = tcp_sk(sk)->mtu_info;
 
-	/* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
-	 * send out by Linux are always <576bytes so they should go through
-	 * unfragmented).
-	 */
-	if (sk->sk_state == TCP_LISTEN)
-		return;
-
 	dst = inet_csk_update_pmtu(sk, mtu);
 	if (!dst)
 		return;
@@ -408,6 +401,13 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 			goto out;
 
 		if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
+			/* We are not interested in TCP_LISTEN and open_requests
+			 * (SYN-ACKs send out by Linux are always <576bytes so
+			 * they should go through unfragmented).
+			 */
+			if (sk->sk_state == TCP_LISTEN)
+				goto out;
+
 			tp->mtu_info = info;
 			if (!sock_owned_by_user(sk)) {
 				tcp_v4_mtu_reduced(sk);