Merge release-20201019.0-115-gdf88f223b (automated)

2 files changed, 12 insertions, 1 deletions

diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go
index 09cb153b1..4e7e5f76a 100644
--- a/pkg/tcpip/header/ipv6.go
+++ b/pkg/tcpip/header/ipv6.go
@@ -375,6 +375,12 @@ func IsV6LinkLocalAddress(addr tcpip.Address) bool {
 	return addr[0] == 0xfe && (addr[1]&0xc0) == 0x80
 }
 
+// IsV6LoopbackAddress determines if the provided address is an IPv6 loopback
+// address.
+func IsV6LoopbackAddress(addr tcpip.Address) bool {
+	return addr == IPv6Loopback
+}
+
 // IsV6LinkLocalMulticastAddress determines if the provided address is an IPv6
 // link-local multicast address.
 func IsV6LinkLocalMulticastAddress(addr tcpip.Address) bool {
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 25ea6b459..ba0e1a7ec 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1210,7 +1210,9 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 
 	isLocalBroadcast := remoteAddr == header.IPv4Broadcast
 	isMulticast := header.IsV4MulticastAddress(remoteAddr) || header.IsV6MulticastAddress(remoteAddr)
-	needRoute := !(isLocalBroadcast || isMulticast || header.IsV6LinkLocalAddress(remoteAddr))
+	isLinkLocal := header.IsV6LinkLocalAddress(remoteAddr) || header.IsV6LinkLocalMulticastAddress(remoteAddr)
+	IsLoopback := header.IsV4LoopbackAddress(remoteAddr) || header.IsV6LoopbackAddress(remoteAddr)
+	needRoute := !(isLocalBroadcast || isMulticast || isLinkLocal || IsLoopback)
 	if id != 0 && !needRoute {
 		if nic, ok := s.nics[id]; ok && nic.Enabled() {
 			if addressEndpoint := s.getAddressEP(nic, localAddr, remoteAddr, netProto); addressEndpoint != nil {
@@ -1246,6 +1248,9 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 	}
 
 	if !needRoute {
+		if IsLoopback {
+			return Route{}, tcpip.ErrBadLocalAddress
+		}
 		return Route{}, tcpip.ErrNetworkUnreachable
 	}