plugeth/p2p/discover/udp_test.go
Felix Lange a98d1d67d6 p2p/discover, p2p/discv5: prevent relay of invalid IPs and low ports
The discovery DHT contains a number of hosts with LAN and loopback IPs.
These get relayed because some implementations do not perform any checks
on the IP.

go-ethereum already prevented relay in most cases because it verifies
that the host actually exists before adding it to the local table. But
this verification causes other issues. We have received several reports
where people's VPSs got shut down by hosting providers because sending
packets to random LAN hosts is indistinguishable from a slow port scan.

The new check prevents sending random packets to LAN by discarding LAN
IPs sent by Internet hosts (and loopback IPs from LAN and Internet
hosts). The new check also blacklists almost all currently registered
special-purpose networks assigned by IANA to avoid inciting random
responses from services in the LAN.

As another precaution against abuse of the DHT, ports below 1024 are now
considered invalid.
2016-11-22 22:21:18 +01:00

563 lines
20 KiB
Go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package discover
import (
"bytes"
"crypto/ecdsa"
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"io"
"math/rand"
"net"
"path/filepath"
"reflect"
"runtime"
"sync"
"testing"
"time"
"github.com/davecgh/go-spew/spew"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/rlp"
)
func init() {
spew.Config.DisableMethods = true
}
// shared test variables
var (
futureExp = uint64(time.Now().Add(10 * time.Hour).Unix())
testTarget = NodeID{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}
testRemote = rpcEndpoint{IP: net.ParseIP("1.1.1.1").To4(), UDP: 1, TCP: 2}
testLocalAnnounced = rpcEndpoint{IP: net.ParseIP("2.2.2.2").To4(), UDP: 3, TCP: 4}
testLocal = rpcEndpoint{IP: net.ParseIP("3.3.3.3").To4(), UDP: 5, TCP: 6}
)
type udpTest struct {
t *testing.T
pipe *dgramPipe
table *Table
udp *udp
sent [][]byte
localkey, remotekey *ecdsa.PrivateKey
remoteaddr *net.UDPAddr
}
func newUDPTest(t *testing.T) *udpTest {
test := &udpTest{
t: t,
pipe: newpipe(),
localkey: newkey(),
remotekey: newkey(),
remoteaddr: &net.UDPAddr{IP: net.IP{10, 0, 1, 99}, Port: 30303},
}
test.table, test.udp, _ = newUDP(test.localkey, test.pipe, nil, "")
return test
}
// handles a packet as if it had been sent to the transport.
func (test *udpTest) packetIn(wantError error, ptype byte, data packet) error {
enc, err := encodePacket(test.remotekey, ptype, data)
if err != nil {
return test.errorf("packet (%d) encode error: %v", ptype, err)
}
test.sent = append(test.sent, enc)
if err = test.udp.handlePacket(test.remoteaddr, enc); err != wantError {
return test.errorf("error mismatch: got %q, want %q", err, wantError)
}
return nil
}
// waits for a packet to be sent by the transport.
// validate should have type func(*udpTest, X) error, where X is a packet type.
func (test *udpTest) waitPacketOut(validate interface{}) error {
dgram := test.pipe.waitPacketOut()
p, _, _, err := decodePacket(dgram)
if err != nil {
return test.errorf("sent packet decode error: %v", err)
}
fn := reflect.ValueOf(validate)
exptype := fn.Type().In(0)
if reflect.TypeOf(p) != exptype {
return test.errorf("sent packet type mismatch, got: %v, want: %v", reflect.TypeOf(p), exptype)
}
fn.Call([]reflect.Value{reflect.ValueOf(p)})
return nil
}
func (test *udpTest) errorf(format string, args ...interface{}) error {
_, file, line, ok := runtime.Caller(2) // errorf + waitPacketOut
if ok {
file = filepath.Base(file)
} else {
file = "???"
line = 1
}
err := fmt.Errorf(format, args...)
fmt.Printf("\t%s:%d: %v\n", file, line, err)
test.t.Fail()
return err
}
func TestUDP_packetErrors(t *testing.T) {
test := newUDPTest(t)
defer test.table.Close()
test.packetIn(errExpired, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version})
test.packetIn(errUnsolicitedReply, pongPacket, &pong{ReplyTok: []byte{}, Expiration: futureExp})
test.packetIn(errUnknownNode, findnodePacket, &findnode{Expiration: futureExp})
test.packetIn(errUnsolicitedReply, neighborsPacket, &neighbors{Expiration: futureExp})
}
func TestUDP_pingTimeout(t *testing.T) {
t.Parallel()
test := newUDPTest(t)
defer test.table.Close()
toaddr := &net.UDPAddr{IP: net.ParseIP("1.2.3.4"), Port: 2222}
toid := NodeID{1, 2, 3, 4}
if err := test.udp.ping(toid, toaddr); err != errTimeout {
t.Error("expected timeout error, got", err)
}
}
func TestUDP_responseTimeouts(t *testing.T) {
t.Parallel()
test := newUDPTest(t)
defer test.table.Close()
rand.Seed(time.Now().UnixNano())
randomDuration := func(max time.Duration) time.Duration {
return time.Duration(rand.Int63n(int64(max)))
}
var (
nReqs = 200
nTimeouts = 0 // number of requests with ptype > 128
nilErr = make(chan error, nReqs) // for requests that get a reply
timeoutErr = make(chan error, nReqs) // for requests that time out
)
for i := 0; i < nReqs; i++ {
// Create a matcher for a random request in udp.loop. Requests
// with ptype <= 128 will not get a reply and should time out.
// For all other requests, a reply is scheduled to arrive
// within the timeout window.
p := &pending{
ptype: byte(rand.Intn(255)),
callback: func(interface{}) bool { return true },
}
binary.BigEndian.PutUint64(p.from[:], uint64(i))
if p.ptype <= 128 {
p.errc = timeoutErr
test.udp.addpending <- p
nTimeouts++
} else {
p.errc = nilErr
test.udp.addpending <- p
time.AfterFunc(randomDuration(60*time.Millisecond), func() {
if !test.udp.handleReply(p.from, p.ptype, nil) {
t.Logf("not matched: %v", p)
}
})
}
time.Sleep(randomDuration(30 * time.Millisecond))
}
// Check that all timeouts were delivered and that the rest got nil errors.
// The replies must be delivered.
var (
recvDeadline = time.After(20 * time.Second)
nTimeoutsRecv, nNil = 0, 0
)
for i := 0; i < nReqs; i++ {
select {
case err := <-timeoutErr:
if err != errTimeout {
t.Fatalf("got non-timeout error on timeoutErr %d: %v", i, err)
}
nTimeoutsRecv++
case err := <-nilErr:
if err != nil {
t.Fatalf("got non-nil error on nilErr %d: %v", i, err)
}
nNil++
case <-recvDeadline:
t.Fatalf("exceeded recv deadline")
}
}
if nTimeoutsRecv != nTimeouts {
t.Errorf("wrong number of timeout errors received: got %d, want %d", nTimeoutsRecv, nTimeouts)
}
if nNil != nReqs-nTimeouts {
t.Errorf("wrong number of successful replies: got %d, want %d", nNil, nReqs-nTimeouts)
}
}
func TestUDP_findnodeTimeout(t *testing.T) {
t.Parallel()
test := newUDPTest(t)
defer test.table.Close()
toaddr := &net.UDPAddr{IP: net.ParseIP("1.2.3.4"), Port: 2222}
toid := NodeID{1, 2, 3, 4}
target := NodeID{4, 5, 6, 7}
result, err := test.udp.findnode(toid, toaddr, target)
if err != errTimeout {
t.Error("expected timeout error, got", err)
}
if len(result) > 0 {
t.Error("expected empty result, got", result)
}
}
func TestUDP_findnode(t *testing.T) {
test := newUDPTest(t)
defer test.table.Close()
// put a few nodes into the table. their exact
// distribution shouldn't matter much, altough we need to
// take care not to overflow any bucket.
targetHash := crypto.Keccak256Hash(testTarget[:])
nodes := &nodesByDistance{target: targetHash}
for i := 0; i < bucketSize; i++ {
nodes.push(nodeAtDistance(test.table.self.sha, i+2), bucketSize)
}
test.table.stuff(nodes.entries)
// ensure there's a bond with the test node,
// findnode won't be accepted otherwise.
test.table.db.updateNode(NewNode(
PubkeyID(&test.remotekey.PublicKey),
test.remoteaddr.IP,
uint16(test.remoteaddr.Port),
99,
))
// check that closest neighbors are returned.
test.packetIn(nil, findnodePacket, &findnode{Target: testTarget, Expiration: futureExp})
expected := test.table.closest(targetHash, bucketSize)
waitNeighbors := func(want []*Node) {
test.waitPacketOut(func(p *neighbors) {
if len(p.Nodes) != len(want) {
t.Errorf("wrong number of results: got %d, want %d", len(p.Nodes), bucketSize)
}
for i := range p.Nodes {
if p.Nodes[i].ID != want[i].ID {
t.Errorf("result mismatch at %d:\n got: %v\n want: %v", i, p.Nodes[i], expected.entries[i])
}
}
})
}
waitNeighbors(expected.entries[:maxNeighbors])
waitNeighbors(expected.entries[maxNeighbors:])
}
func TestUDP_findnodeMultiReply(t *testing.T) {
test := newUDPTest(t)
defer test.table.Close()
// queue a pending findnode request
resultc, errc := make(chan []*Node), make(chan error)
go func() {
rid := PubkeyID(&test.remotekey.PublicKey)
ns, err := test.udp.findnode(rid, test.remoteaddr, testTarget)
if err != nil && len(ns) == 0 {
errc <- err
} else {
resultc <- ns
}
}()
// wait for the findnode to be sent.
// after it is sent, the transport is waiting for a reply
test.waitPacketOut(func(p *findnode) {
if p.Target != testTarget {
t.Errorf("wrong target: got %v, want %v", p.Target, testTarget)
}
})
// send the reply as two packets.
list := []*Node{
MustParseNode("enode://ba85011c70bcc5c04d8607d3a0ed29aa6179c092cbdda10d5d32684fb33ed01bd94f588ca8f91ac48318087dcb02eaf36773a7a453f0eedd6742af668097b29c@10.0.1.16:30303?discport=30304"),
MustParseNode("enode://81fa361d25f157cd421c60dcc28d8dac5ef6a89476633339c5df30287474520caca09627da18543d9079b5b288698b542d56167aa5c09111e55acdbbdf2ef799@10.0.1.16:30303"),
MustParseNode("enode://9bffefd833d53fac8e652415f4973bee289e8b1a5c6c4cbe70abf817ce8a64cee11b823b66a987f51aaa9fba0d6a91b3e6bf0d5a5d1042de8e9eeea057b217f8@10.0.1.36:30301?discport=17"),
MustParseNode("enode://1b5b4aa662d7cb44a7221bfba67302590b643028197a7d5214790f3bac7aaa4a3241be9e83c09cf1f6c69d007c634faae3dc1b1221793e8446c0b3a09de65960@10.0.1.16:30303"),
}
rpclist := make([]rpcNode, len(list))
for i := range list {
rpclist[i] = nodeToRPC(list[i])
}
test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[:2]})
test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[2:]})
// check that the sent neighbors are all returned by findnode
select {
case result := <-resultc:
want := append(list[:2], list[3:]...)
if !reflect.DeepEqual(result, want) {
t.Errorf("neighbors mismatch:\n got: %v\n want: %v", result, want)
}
case err := <-errc:
t.Errorf("findnode error: %v", err)
case <-time.After(5 * time.Second):
t.Error("findnode did not return within 5 seconds")
}
}
func TestUDP_successfulPing(t *testing.T) {
test := newUDPTest(t)
added := make(chan *Node, 1)
test.table.nodeAddedHook = func(n *Node) { added <- n }
defer test.table.Close()
// The remote side sends a ping packet to initiate the exchange.
go test.packetIn(nil, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version, Expiration: futureExp})
// the ping is replied to.
test.waitPacketOut(func(p *pong) {
pinghash := test.sent[0][:macSize]
if !bytes.Equal(p.ReplyTok, pinghash) {
t.Errorf("got pong.ReplyTok %x, want %x", p.ReplyTok, pinghash)
}
wantTo := rpcEndpoint{
// The mirrored UDP address is the UDP packet sender
IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
// The mirrored TCP port is the one from the ping packet
TCP: testRemote.TCP,
}
if !reflect.DeepEqual(p.To, wantTo) {
t.Errorf("got pong.To %v, want %v", p.To, wantTo)
}
})
// remote is unknown, the table pings back.
test.waitPacketOut(func(p *ping) error {
if !reflect.DeepEqual(p.From, test.udp.ourEndpoint) {
t.Errorf("got ping.From %v, want %v", p.From, test.udp.ourEndpoint)
}
wantTo := rpcEndpoint{
// The mirrored UDP address is the UDP packet sender.
IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
TCP: 0,
}
if !reflect.DeepEqual(p.To, wantTo) {
t.Errorf("got ping.To %v, want %v", p.To, wantTo)
}
return nil
})
test.packetIn(nil, pongPacket, &pong{Expiration: futureExp})
// the node should be added to the table shortly after getting the
// pong packet.
select {
case n := <-added:
rid := PubkeyID(&test.remotekey.PublicKey)
if n.ID != rid {
t.Errorf("node has wrong ID: got %v, want %v", n.ID, rid)
}
if !bytes.Equal(n.IP, test.remoteaddr.IP) {
t.Errorf("node has wrong IP: got %v, want: %v", n.IP, test.remoteaddr.IP)
}
if int(n.UDP) != test.remoteaddr.Port {
t.Errorf("node has wrong UDP port: got %v, want: %v", n.UDP, test.remoteaddr.Port)
}
if n.TCP != testRemote.TCP {
t.Errorf("node has wrong TCP port: got %v, want: %v", n.TCP, testRemote.TCP)
}
case <-time.After(2 * time.Second):
t.Errorf("node was not added within 2 seconds")
}
}
var testPackets = []struct {
input string
wantPacket interface{}
}{
{
input: "71dbda3a79554728d4f94411e42ee1f8b0d561c10e1e5f5893367948c6a7d70bb87b235fa28a77070271b6c164a2dce8c7e13a5739b53b5e96f2e5acb0e458a02902f5965d55ecbeb2ebb6cabb8b2b232896a36b737666c55265ad0a68412f250001ea04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a355",
wantPacket: &ping{
Version: 4,
From: rpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
To: rpcEndpoint{net.ParseIP("::1"), 2222, 3333},
Expiration: 1136239445,
Rest: []rlp.RawValue{},
},
},
{
input: "e9614ccfd9fc3e74360018522d30e1419a143407ffcce748de3e22116b7e8dc92ff74788c0b6663aaa3d67d641936511c8f8d6ad8698b820a7cf9e1be7155e9a241f556658c55428ec0563514365799a4be2be5a685a80971ddcfa80cb422cdd0101ec04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a3550102",
wantPacket: &ping{
Version: 4,
From: rpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
To: rpcEndpoint{net.ParseIP("::1"), 2222, 3333},
Expiration: 1136239445,
Rest: []rlp.RawValue{{0x01}, {0x02}},
},
},
{
input: "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",
wantPacket: &ping{
Version: 555,
From: rpcEndpoint{net.ParseIP("2001:db8:3c4d:15::abcd:ef12"), 3322, 5544},
To: rpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
Expiration: 1136239445,
Rest: []rlp.RawValue{{0xC5, 0x01, 0x02, 0x03, 0x04, 0x05}},
},
},
{
input: "09b2428d83348d27cdf7064ad9024f526cebc19e4958f0fdad87c15eb598dd61d08423e0bf66b2069869e1724125f820d851c136684082774f870e614d95a2855d000f05d1648b2d5945470bc187c2d2216fbe870f43ed0909009882e176a46b0102f846d79020010db885a308d313198a2e037073488208ae82823aa0fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c9548443b9a355c6010203c2040506a0c969a58f6f9095004c0177a6b47f451530cab38966a25cca5cb58f055542124e",
wantPacket: &pong{
To: rpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
ReplyTok: common.Hex2Bytes("fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c954"),
Expiration: 1136239445,
Rest: []rlp.RawValue{{0xC6, 0x01, 0x02, 0x03, 0xC2, 0x04, 0x05}, {0x06}},
},
},
{
input: "c7c44041b9f7c7e41934417ebac9a8e1a4c6298f74553f2fcfdcae6ed6fe53163eb3d2b52e39fe91831b8a927bf4fc222c3902202027e5e9eb812195f95d20061ef5cd31d502e47ecb61183f74a504fe04c51e73df81f25c4d506b26db4517490103f84eb840ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f8443b9a35582999983999999280dc62cc8255c73471e0a61da0c89acdc0e035e260add7fc0c04ad9ebf3919644c91cb247affc82b69bd2ca235c71eab8e49737c937a2c396",
wantPacket: &findnode{
Target: MustHexID("ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f"),
Expiration: 1136239445,
Rest: []rlp.RawValue{{0x82, 0x99, 0x99}, {0x83, 0x99, 0x99, 0x99}},
},
},
{
input: "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",
wantPacket: &neighbors{
Nodes: []rpcNode{
{
ID: MustHexID("3155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32"),
IP: net.ParseIP("99.33.22.55").To4(),
UDP: 4444,
TCP: 4445,
},
{
ID: MustHexID("312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069db"),
IP: net.ParseIP("1.2.3.4").To4(),
UDP: 1,
TCP: 1,
},
{
ID: MustHexID("38643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aac"),
IP: net.ParseIP("2001:db8:3c4d:15::abcd:ef12"),
UDP: 3333,
TCP: 3333,
},
{
ID: MustHexID("8dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df73"),
IP: net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"),
UDP: 999,
TCP: 1000,
},
},
Expiration: 1136239445,
Rest: []rlp.RawValue{{0x01}, {0x02}, {0x03}},
},
},
}
func TestForwardCompatibility(t *testing.T) {
testkey, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
wantNodeID := PubkeyID(&testkey.PublicKey)
for _, test := range testPackets {
input, err := hex.DecodeString(test.input)
if err != nil {
t.Fatalf("invalid hex: %s", test.input)
}
packet, nodeid, _, err := decodePacket(input)
if err != nil {
t.Errorf("did not accept packet %s\n%v", test.input, err)
continue
}
if !reflect.DeepEqual(packet, test.wantPacket) {
t.Errorf("got %s\nwant %s", spew.Sdump(packet), spew.Sdump(test.wantPacket))
}
if nodeid != wantNodeID {
t.Errorf("got id %v\nwant id %v", nodeid, wantNodeID)
}
}
}
// dgramPipe is a fake UDP socket. It queues all sent datagrams.
type dgramPipe struct {
mu *sync.Mutex
cond *sync.Cond
closing chan struct{}
closed bool
queue [][]byte
}
func newpipe() *dgramPipe {
mu := new(sync.Mutex)
return &dgramPipe{
closing: make(chan struct{}),
cond: &sync.Cond{L: mu},
mu: mu,
}
}
// WriteToUDP queues a datagram.
func (c *dgramPipe) WriteToUDP(b []byte, to *net.UDPAddr) (n int, err error) {
msg := make([]byte, len(b))
copy(msg, b)
c.mu.Lock()
defer c.mu.Unlock()
if c.closed {
return 0, errors.New("closed")
}
c.queue = append(c.queue, msg)
c.cond.Signal()
return len(b), nil
}
// ReadFromUDP just hangs until the pipe is closed.
func (c *dgramPipe) ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error) {
<-c.closing
return 0, nil, io.EOF
}
func (c *dgramPipe) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if !c.closed {
close(c.closing)
c.closed = true
}
return nil
}
func (c *dgramPipe) LocalAddr() net.Addr {
return &net.UDPAddr{IP: testLocal.IP, Port: int(testLocal.UDP)}
}
func (c *dgramPipe) waitPacketOut() []byte {
c.mu.Lock()
defer c.mu.Unlock()
for len(c.queue) == 0 {
c.cond.Wait()
}
p := c.queue[0]
copy(c.queue, c.queue[1:])
c.queue = c.queue[:len(c.queue)-1]
return p
}