Merge pull request #3325 from fjl/p2p-netrestrict

Prevent relay of invalid IPs, add --netrestrict

1 files changed, 30 insertions, 20 deletions

diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
index 74758b6fd..e09c63ffb 100644
--- a/p2p/discover/udp.go
+++ b/p2p/discover/udp.go
@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/p2p/nat"
+	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
@@ -126,8 +127,16 @@ func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
 	return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
 }
 
-func nodeFromRPC(rn rpcNode) (*Node, error) {
-	// TODO: don't accept localhost, LAN addresses from internet hosts
+func (t *udp) nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*Node, error) {
+	if rn.UDP <= 1024 {
+		return nil, errors.New("low port")
+	}
+	if err := netutil.CheckRelayIP(sender.IP, rn.IP); err != nil {
+		return nil, err
+	}
+	if t.netrestrict != nil && !t.netrestrict.Contains(rn.IP) {
+		return nil, errors.New("not contained in netrestrict whitelist")
+	}
 	n := NewNode(rn.ID, rn.IP, rn.UDP, rn.TCP)
 	err := n.validateComplete()
 	return n, err
@@ -151,6 +160,7 @@ type conn interface {
 // udp implements the RPC protocol.
 type udp struct {
 	conn        conn
+	netrestrict *netutil.Netlist
 	priv        *ecdsa.PrivateKey
 	ourEndpoint rpcEndpoint
 
@@ -201,7 +211,7 @@ type reply struct {
 }
 
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBPath string) (*Table, error) {
+func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, error) {
 	addr, err := net.ResolveUDPAddr("udp", laddr)
 	if err != nil {
 		return nil, err
@@ -210,7 +220,7 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBP
 	if err != nil {
 		return nil, err
 	}
-	tab, _, err := newUDP(priv, conn, natm, nodeDBPath)
+	tab, _, err := newUDP(priv, conn, natm, nodeDBPath, netrestrict)
 	if err != nil {
 		return nil, err
 	}
@@ -218,13 +228,14 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBP
 	return tab, nil
 }
 
-func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath string) (*Table, *udp, error) {
+func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, *udp, error) {
 	udp := &udp{
-		conn:       c,
-		priv:       priv,
-		closing:    make(chan struct{}),
-		gotreply:   make(chan reply),
-		addpending: make(chan *pending),
+		conn:        c,
+		priv:        priv,
+		netrestrict: netrestrict,
+		closing:     make(chan struct{}),
+		gotreply:    make(chan reply),
+		addpending:  make(chan *pending),
 	}
 	realaddr := c.LocalAddr().(*net.UDPAddr)
 	if natm != nil {
@@ -281,9 +292,12 @@ func (t *udp) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node
 		reply := r.(*neighbors)
 		for _, rn := range reply.Nodes {
 			nreceived++
-			if n, err := nodeFromRPC(rn); err == nil {
-				nodes = append(nodes, n)
+			n, err := t.nodeFromRPC(toaddr, rn)
+			if err != nil {
+				glog.V(logger.Detail).Infof("invalid neighbor node (%v) from %v: %v", rn.IP, toaddr, err)
+				continue
 			}
+			nodes = append(nodes, n)
 		}
 		return nreceived >= bucketSize
 	})
@@ -479,13 +493,6 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) ([]byte,
 	return packet, nil
 }
 
-func isTemporaryError(err error) bool {
-	tempErr, ok := err.(interface {
-		Temporary() bool
-	})
-	return ok && tempErr.Temporary() || isPacketTooBig(err)
-}
-
 // readLoop runs in its own goroutine. it handles incoming UDP packets.
 func (t *udp) readLoop() {
 	defer t.conn.Close()
@@ -495,7 +502,7 @@ func (t *udp) readLoop() {
 	buf := make([]byte, 1280)
 	for {
 		nbytes, from, err := t.conn.ReadFromUDP(buf)
-		if isTemporaryError(err) {
+		if netutil.IsTemporaryError(err) {
 			// Ignore temporary read errors.
 			glog.V(logger.Debug).Infof("Temporary read error: %v", err)
 			continue
@@ -602,6 +609,9 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 	// Send neighbors in chunks with at most maxNeighbors per packet
 	// to stay below the 1280 byte limit.
 	for i, n := range closest {
+		if netutil.CheckRelayIP(from.IP, n.IP) != nil {
+			continue
+		}
 		p.Nodes = append(p.Nodes, nodeToRPC(n))
 		if len(p.Nodes) == maxNeighbors || i == len(closest)-1 {
 			t.send(from, neighborsPacket, p)