mirror of
https://gitlab.com/pulsechaincom/go-pulse.git
synced 2024-12-25 12:57:17 +00:00
de7af720d6
This a fix for an attack vector where the discovery protocol could be used to amplify traffic in a DDOS attack. A malicious actor would send a findnode request with the IP address and UDP port of the target as the source address. The recipient of the findnode packet would then send a neighbors packet (which is 16x the size of findnode) to the victim. Our solution is to require a 'bond' with the sender of findnode. If no bond exists, the findnode packet is not processed. A bond between nodes α and β is created when α replies to a ping from β. This (initial) version of the bonding implementation might still be vulnerable against replay attacks during the expiration time window. We will add stricter source address validation later.
282 lines
7.4 KiB
Go
282 lines
7.4 KiB
Go
package discover
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import (
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"crypto/ecdsa"
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"fmt"
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"math/rand"
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"net"
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"reflect"
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"testing"
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"testing/quick"
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"github.com/ethereum/go-ethereum/crypto"
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)
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func TestTable_pingReplace(t *testing.T) {
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doit := func(newNodeIsResponding, lastInBucketIsResponding bool) {
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transport := newPingRecorder()
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tab := newTable(transport, NodeID{}, &net.UDPAddr{})
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last := fillBucket(tab, 200)
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pingSender := randomID(tab.self.ID, 200)
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// this gotPing should replace the last node
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// if the last node is not responding.
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transport.responding[last.ID] = lastInBucketIsResponding
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transport.responding[pingSender] = newNodeIsResponding
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tab.bond(true, pingSender, &net.UDPAddr{}, 0)
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// first ping goes to sender (bonding pingback)
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if !transport.pinged[pingSender] {
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t.Error("table did not ping back sender")
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}
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if newNodeIsResponding {
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// second ping goes to oldest node in bucket
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// to see whether it is still alive.
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if !transport.pinged[last.ID] {
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t.Error("table did not ping last node in bucket")
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}
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}
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tab.mutex.Lock()
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defer tab.mutex.Unlock()
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if l := len(tab.buckets[200].entries); l != bucketSize {
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t.Errorf("wrong bucket size after gotPing: got %d, want %d", bucketSize, l)
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}
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if lastInBucketIsResponding || !newNodeIsResponding {
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if !contains(tab.buckets[200].entries, last.ID) {
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t.Error("last entry was removed")
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}
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if contains(tab.buckets[200].entries, pingSender) {
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t.Error("new entry was added")
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}
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} else {
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if contains(tab.buckets[200].entries, last.ID) {
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t.Error("last entry was not removed")
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}
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if !contains(tab.buckets[200].entries, pingSender) {
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t.Error("new entry was not added")
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}
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}
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}
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doit(true, true)
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doit(false, true)
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doit(false, true)
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doit(false, false)
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}
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func fillBucket(tab *Table, ld int) (last *Node) {
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b := tab.buckets[ld]
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for len(b.entries) < bucketSize {
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b.entries = append(b.entries, &Node{ID: randomID(tab.self.ID, ld)})
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}
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return b.entries[bucketSize-1]
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}
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type pingRecorder struct{ responding, pinged map[NodeID]bool }
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func newPingRecorder() *pingRecorder {
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return &pingRecorder{make(map[NodeID]bool), make(map[NodeID]bool)}
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}
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func (t *pingRecorder) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
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panic("findnode called on pingRecorder")
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}
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func (t *pingRecorder) close() {
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panic("close called on pingRecorder")
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}
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func (t *pingRecorder) waitping(from NodeID) error {
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return nil // remote always pings
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}
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func (t *pingRecorder) ping(toid NodeID, toaddr *net.UDPAddr) error {
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t.pinged[toid] = true
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if t.responding[toid] {
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return nil
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} else {
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return errTimeout
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}
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}
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func TestTable_closest(t *testing.T) {
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t.Parallel()
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test := func(test *closeTest) bool {
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// for any node table, Target and N
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tab := newTable(nil, test.Self, &net.UDPAddr{})
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tab.add(test.All)
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// check that doClosest(Target, N) returns nodes
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result := tab.closest(test.Target, test.N).entries
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if hasDuplicates(result) {
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t.Errorf("result contains duplicates")
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return false
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}
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if !sortedByDistanceTo(test.Target, result) {
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t.Errorf("result is not sorted by distance to target")
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return false
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}
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// check that the number of results is min(N, tablen)
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wantN := test.N
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if tlen := tab.len(); tlen < test.N {
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wantN = tlen
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}
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if len(result) != wantN {
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t.Errorf("wrong number of nodes: got %d, want %d", len(result), wantN)
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return false
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} else if len(result) == 0 {
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return true // no need to check distance
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}
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// check that the result nodes have minimum distance to target.
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for _, b := range tab.buckets {
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for _, n := range b.entries {
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if contains(result, n.ID) {
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continue // don't run the check below for nodes in result
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}
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farthestResult := result[len(result)-1].ID
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if distcmp(test.Target, n.ID, farthestResult) < 0 {
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t.Errorf("table contains node that is closer to target but it's not in result")
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t.Logf(" Target: %v", test.Target)
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t.Logf(" Farthest Result: %v", farthestResult)
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t.Logf(" ID: %v", n.ID)
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return false
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}
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}
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}
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return true
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}
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if err := quick.Check(test, quickcfg); err != nil {
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t.Error(err)
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}
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}
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type closeTest struct {
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Self NodeID
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Target NodeID
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All []*Node
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N int
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}
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func (*closeTest) Generate(rand *rand.Rand, size int) reflect.Value {
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t := &closeTest{
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Self: gen(NodeID{}, rand).(NodeID),
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Target: gen(NodeID{}, rand).(NodeID),
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N: rand.Intn(bucketSize),
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}
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for _, id := range gen([]NodeID{}, rand).([]NodeID) {
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t.All = append(t.All, &Node{ID: id})
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}
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return reflect.ValueOf(t)
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}
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func TestTable_Lookup(t *testing.T) {
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self := gen(NodeID{}, quickrand).(NodeID)
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target := randomID(self, 200)
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transport := findnodeOracle{t, target}
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tab := newTable(transport, self, &net.UDPAddr{})
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// lookup on empty table returns no nodes
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if results := tab.Lookup(target); len(results) > 0 {
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t.Fatalf("lookup on empty table returned %d results: %#v", len(results), results)
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}
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// seed table with initial node (otherwise lookup will terminate immediately)
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tab.add([]*Node{newNode(randomID(target, 200), &net.UDPAddr{Port: 200})})
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results := tab.Lookup(target)
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t.Logf("results:")
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for _, e := range results {
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t.Logf(" ld=%d, %v", logdist(target, e.ID), e.ID)
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}
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if len(results) != bucketSize {
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t.Errorf("wrong number of results: got %d, want %d", len(results), bucketSize)
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}
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if hasDuplicates(results) {
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t.Errorf("result set contains duplicate entries")
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}
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if !sortedByDistanceTo(target, results) {
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t.Errorf("result set not sorted by distance to target")
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}
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if !contains(results, target) {
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t.Errorf("result set does not contain target")
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}
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}
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// findnode on this transport always returns at least one node
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// that is one bucket closer to the target.
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type findnodeOracle struct {
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t *testing.T
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target NodeID
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}
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func (t findnodeOracle) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
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t.t.Logf("findnode query at dist %d", toaddr.Port)
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// current log distance is encoded in port number
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var result []*Node
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switch toaddr.Port {
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case 0:
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panic("query to node at distance 0")
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default:
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// TODO: add more randomness to distances
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next := toaddr.Port - 1
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for i := 0; i < bucketSize; i++ {
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result = append(result, &Node{ID: randomID(t.target, next), DiscPort: next})
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}
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}
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return result, nil
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}
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func (t findnodeOracle) close() {}
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func (t findnodeOracle) waitping(from NodeID) error { return nil }
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func (t findnodeOracle) ping(toid NodeID, toaddr *net.UDPAddr) error { return nil }
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func hasDuplicates(slice []*Node) bool {
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seen := make(map[NodeID]bool)
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for _, e := range slice {
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if seen[e.ID] {
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return true
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}
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seen[e.ID] = true
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}
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return false
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}
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func sortedByDistanceTo(distbase NodeID, slice []*Node) bool {
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var last NodeID
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for i, e := range slice {
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if i > 0 && distcmp(distbase, e.ID, last) < 0 {
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return false
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}
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last = e.ID
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}
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return true
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}
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func contains(ns []*Node, id NodeID) bool {
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for _, n := range ns {
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if n.ID == id {
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return true
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}
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}
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return false
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}
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// gen wraps quick.Value so it's easier to use.
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// it generates a random value of the given value's type.
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func gen(typ interface{}, rand *rand.Rand) interface{} {
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v, ok := quick.Value(reflect.TypeOf(typ), rand)
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if !ok {
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panic(fmt.Sprintf("couldn't generate random value of type %T", typ))
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}
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return v.Interface()
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}
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func newkey() *ecdsa.PrivateKey {
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key, err := crypto.GenerateKey()
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if err != nil {
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panic("couldn't generate key: " + err.Error())
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}
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return key
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}
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