1 files changed, 25 insertions, 7 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9409887fb664..8c97cd1048c2 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -477,6 +477,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 	int rel_msg = 0;
 	u8 rel_type = ICMPV6_DEST_UNREACH;
 	u8 rel_code = ICMPV6_ADDR_UNREACH;
+	u8 tproto;
 	__u32 rel_info = 0;
 	__u16 len;
 	int err = -ENOENT;
@@ -490,7 +491,8 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 					&ipv6h->saddr)) == NULL)
 		goto out;
 
-	if (t->parms.proto != ipproto && t->parms.proto != 0)
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if (tproto != ipproto && tproto != 0)
 		goto out;
 
 	err = 0;
@@ -791,6 +793,7 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 {
 	struct ip6_tnl *t;
 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	u8 tproto;
 	int err;
 
 	rcu_read_lock();
@@ -799,7 +802,8 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
 					&ipv6h->daddr)) != NULL) {
 		struct pcpu_sw_netstats *tstats;
 
-		if (t->parms.proto != ipproto && t->parms.proto != 0) {
+		tproto = ACCESS_ONCE(t->parms.proto);
+		if (tproto != ipproto && tproto != 0) {
 			rcu_read_unlock();
 			goto discard;
 		}
@@ -1078,9 +1082,11 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPIP && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t))
 		return -1;
 
@@ -1120,9 +1126,11 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct flowi6 fl6;
 	__u8 dsfield;
 	__u32 mtu;
+	u8 tproto;
 	int err;
 
-	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
 		return -1;
 
@@ -1285,6 +1293,14 @@ static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
 	return err;
 }
 
+static int ip6_tnl0_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
+{
+	/* for default tnl0 device allow to change only the proto */
+	t->parms.proto = p->proto;
+	netdev_state_change(t->dev);
+	return 0;
+}
+
 static void
 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
 {
@@ -1384,7 +1400,7 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 			break;
 		ip6_tnl_parm_from_user(&p1, &p);
 		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
-		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
+		if (cmd == SIOCCHGTUNNEL) {
 			if (t != NULL) {
 				if (t->dev != dev) {
 					err = -EEXIST;
@@ -1392,8 +1408,10 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 				}
 			} else
 				t = netdev_priv(dev);
-
-			err = ip6_tnl_update(t, &p1);
+			if (dev == ip6n->fb_tnl_dev)
+				err = ip6_tnl0_update(t, &p1);
+			else
+				err = ip6_tnl_update(t, &p1);
 		}
 		if (t) {
 			err = 0;