4 files changed, 49 insertions, 15 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 98e4a63d72bb..b6030025f411 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4903,6 +4903,21 @@ int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
 	return ret;
 }
 
+static
+int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
+			void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct inet6_dev *idev = ctl->extra1;
+	int min_mtu = IPV6_MIN_MTU;
+	struct ctl_table lctl;
+
+	lctl = *ctl;
+	lctl.extra1 = &min_mtu;
+	lctl.extra2 = idev ? &idev->dev->mtu : NULL;
+
+	return proc_dointvec_minmax(&lctl, write, buffer, lenp, ppos);
+}
+
 static void dev_disable_change(struct inet6_dev *idev)
 {
 	struct netdev_notifier_info info;
@@ -5054,7 +5069,7 @@ static struct addrconf_sysctl_table
 			.data		= &ipv6_devconf.mtu6,
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
-			.proc_handler	= proc_dointvec,
+			.proc_handler	= addrconf_sysctl_mtu,
 		},
 		{
 			.procname	= "accept_ra",
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index c215be70cac0..ace8daca5c83 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -325,14 +325,34 @@ void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
 	kfree_skb(skb);
 }
 
-static void ip6_datagram_prepare_pktinfo_errqueue(struct sk_buff *skb)
+/* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL.
+ *
+ * At one point, excluding local errors was a quick test to identify icmp/icmp6
+ * errors. This is no longer true, but the test remained, so the v6 stack,
+ * unlike v4, also honors cmsg requests on all wifi and timestamp errors.
+ *
+ * Timestamp code paths do not initialize the fields expected by cmsg:
+ * the PKTINFO fields in skb->cb[]. Fill those in here.
+ */
+static bool ip6_datagram_support_cmsg(struct sk_buff *skb,
+				      struct sock_exterr_skb *serr)
 {
-	int ifindex = skb->dev ? skb->dev->ifindex : -1;
+	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
+	    serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)
+		return true;
+
+	if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)
+		return false;
+
+	if (!skb->dev)
+		return false;
 
 	if (skb->protocol == htons(ETH_P_IPV6))
-		IP6CB(skb)->iif = ifindex;
+		IP6CB(skb)->iif = skb->dev->ifindex;
 	else
-		PKTINFO_SKB_CB(skb)->ipi_ifindex = ifindex;
+		PKTINFO_SKB_CB(skb)->ipi_ifindex = skb->dev->ifindex;
+
+	return true;
 }
 
 /*
@@ -369,7 +389,7 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 
 	serr = SKB_EXT_ERR(skb);
 
-	if (sin && skb->len) {
+	if (sin && serr->port) {
 		const unsigned char *nh = skb_network_header(skb);
 		sin->sin6_family = AF_INET6;
 		sin->sin6_flowinfo = 0;
@@ -394,14 +414,11 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
 	sin = &errhdr.offender;
 	memset(sin, 0, sizeof(*sin));
-	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL && skb->len) {
+
+	if (ip6_datagram_support_cmsg(skb, serr)) {
 		sin->sin6_family = AF_INET6;
-		if (np->rxopt.all) {
-			if (serr->ee.ee_origin != SO_EE_ORIGIN_ICMP &&
-			    serr->ee.ee_origin != SO_EE_ORIGIN_ICMP6)
-				ip6_datagram_prepare_pktinfo_errqueue(skb);
+		if (np->rxopt.all)
 			ip6_datagram_recv_common_ctl(sk, msg, skb);
-		}
 		if (skb->protocol == htons(ETH_P_IPV6)) {
 			sin->sin6_addr = ipv6_hdr(skb)->saddr;
 			if (np->rxopt.all)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 7deebf102cba..0a04a37305d5 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1298,7 +1298,8 @@ emsgsize:
 	if (((length > mtu) ||
 	     (skb && skb_is_gso(skb))) &&
 	    (sk->sk_protocol == IPPROTO_UDP) &&
-	    (rt->dst.dev->features & NETIF_F_UFO)) {
+	    (rt->dst.dev->features & NETIF_F_UFO) &&
+	    (sk->sk_type == SOCK_DGRAM)) {
 		err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
 					  hh_len, fragheaderlen,
 					  transhdrlen, mtu, flags, rt);
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index bd46f736f61d..a2dfff6ff227 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -102,9 +102,10 @@ int ping_v6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
 	if (msg->msg_name) {
 		DECLARE_SOCKADDR(struct sockaddr_in6 *, u, msg->msg_name);
-		if (msg->msg_namelen < sizeof(struct sockaddr_in6) ||
-		    u->sin6_family != AF_INET6) {
+		if (msg->msg_namelen < sizeof(*u))
 			return -EINVAL;
+		if (u->sin6_family != AF_INET6) {
+			return -EAFNOSUPPORT;
 		}
 		if (sk->sk_bound_dev_if &&
 		    sk->sk_bound_dev_if != u->sin6_scope_id) {