whisper: filter id type changed to enhance security

cmd/wnode/main.go

@@ -66,7 +66,7 @@ var (
 	asymKey    *ecdsa.PrivateKey
 	nodeid     *ecdsa.PrivateKey
 	topic      whisper.TopicType
-	filterID   uint32
+	filterID   string
 	symPass    string
 	msPassword string
 )

whisper/whisperv5/api.go

@@ -151,9 +151,9 @@ func (api *PublicWhisperAPI) DeleteSymKey(name string) error {
 
 // NewWhisperFilter creates and registers a new message filter to watch for inbound whisper messages.
 // Returns the ID of the newly created Filter.
-func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (uint32, error) {
+func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (string, error) {
 	if api.whisper == nil {
-		return 0, whisperOffLineErr
+		return "", whisperOffLineErr
 	}
 
 	filter := Filter{
@@ -171,25 +171,25 @@ func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (uint32, error) {
 	if len(args.Topics) == 0 {
 		info := "NewFilter: at least one topic must be specified"
 		glog.V(logger.Error).Infof(info)
-		return 0, errors.New(info)
+		return "", errors.New(info)
 	}
 
 	if len(args.KeyName) != 0 && len(filter.KeySym) == 0 {
 		info := "NewFilter: key was not found by name: " + args.KeyName
 		glog.V(logger.Error).Infof(info)
-		return 0, errors.New(info)
+		return "", errors.New(info)
 	}
 
 	if len(args.To) == 0 && len(filter.KeySym) == 0 {
 		info := "NewFilter: filter must contain either symmetric or asymmetric key"
 		glog.V(logger.Error).Infof(info)
-		return 0, errors.New(info)
+		return "", errors.New(info)
 	}
 
 	if len(args.To) != 0 && len(filter.KeySym) != 0 {
 		info := "NewFilter: filter must not contain both symmetric and asymmetric key"
 		glog.V(logger.Error).Infof(info)
-		return 0, errors.New(info)
+		return "", errors.New(info)
 	}
 
 	if len(args.To) > 0 {
@@ -197,13 +197,13 @@ func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (uint32, error) {
 		if !ValidatePublicKey(dst) {
 			info := "NewFilter: Invalid 'To' address"
 			glog.V(logger.Error).Infof(info)
-			return 0, errors.New(info)
+			return "", errors.New(info)
 		}
 		filter.KeyAsym = api.whisper.GetIdentity(string(args.To))
 		if filter.KeyAsym == nil {
 			info := "NewFilter: non-existent identity provided"
 			glog.V(logger.Error).Infof(info)
-			return 0, errors.New(info)
+			return "", errors.New(info)
 		}
 	}
 
@@ -211,7 +211,7 @@ func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (uint32, error) {
 		if !ValidatePublicKey(filter.Src) {
 			info := "NewFilter: Invalid 'From' address"
 			glog.V(logger.Error).Infof(info)
-			return 0, errors.New(info)
+			return "", errors.New(info)
 		}
 	}
 
@@ -220,12 +220,12 @@ func (api *PublicWhisperAPI) NewFilter(args WhisperFilterArgs) (uint32, error) {
 }
 
 // UninstallFilter disables and removes an existing filter.
-func (api *PublicWhisperAPI) UninstallFilter(filterId uint32) {
+func (api *PublicWhisperAPI) UninstallFilter(filterId string) {
 	api.whisper.Unwatch(filterId)
 }
 
 // GetFilterChanges retrieves all the new messages matched by a filter since the last retrieval.
-func (api *PublicWhisperAPI) GetFilterChanges(filterId uint32) []*WhisperMessage {
+func (api *PublicWhisperAPI) GetFilterChanges(filterId string) []*WhisperMessage {
 	f := api.whisper.GetFilter(filterId)
 	if f != nil {
 		newMail := f.Retrieve()
@@ -235,7 +235,7 @@ func (api *PublicWhisperAPI) GetFilterChanges(filterId uint32) []*WhisperMessage
 }
 
 // GetMessages retrieves all the known messages that match a specific filter.
-func (api *PublicWhisperAPI) GetMessages(filterId uint32) []*WhisperMessage {
+func (api *PublicWhisperAPI) GetMessages(filterId string) []*WhisperMessage {
 	all := api.whisper.Messages(filterId)
 	return toWhisperMessages(all)
 }
@@ -282,7 +282,7 @@ func (api *PublicWhisperAPI) Post(args PostArgs) error {
 	}
 
 	filter := api.whisper.GetFilter(args.FilterID)
-	if filter == nil && args.FilterID > 0 {
+	if filter == nil && len(args.FilterID) > 0 {
 		info := fmt.Sprintf("Post: wrong filter id %d", args.FilterID)
 		glog.V(logger.Error).Infof(info)
 		return errors.New(info)
@@ -374,7 +374,7 @@ type PostArgs struct {
 	Payload  hexutil.Bytes `json:"payload"`
 	WorkTime uint32        `json:"worktime"`
 	PoW      float64       `json:"pow"`
-	FilterID uint32        `json:"filterID"`
+	FilterID string        `json:"filterID"`
 	PeerID   hexutil.Bytes `json:"peerID"`
 }
 

whisper/whisperv5/api_test.go

@@ -42,7 +42,7 @@ func TestBasic(t *testing.T) {
 		t.Fatalf("wrong version: %d.", ver)
 	}
 
-	mail := api.GetFilterChanges(1)
+	mail := api.GetFilterChanges("non-existent-id")
 	if len(mail) != 0 {
 		t.Fatalf("failed GetFilterChanges: premature result")
 	}
@@ -212,7 +212,7 @@ func TestUnmarshalPostArgs(t *testing.T) {
 	"payload":"0x7061796C6F61642073686F756C642062652070736575646F72616E646F6D",
 	"worktime":777,
 	"pow":3.1416,
-	"filterID":64,
+	"filterID":"test-filter-id",
 	"peerID":"0xf26e7779"
 	}`)
 
@@ -249,7 +249,7 @@ func TestUnmarshalPostArgs(t *testing.T) {
 	if a.PoW != 3.1416 {
 		t.Fatalf("wrong pow: %f.", a.PoW)
 	}
-	if a.FilterID != 64 {
+	if a.FilterID != "test-filter-id" {
 		t.Fatalf("wrong FilterID: %d.", a.FilterID)
 	}
 	if !bytes.Equal(a.PeerID[:], a.Topic[:]) {
@@ -257,7 +257,7 @@ func TestUnmarshalPostArgs(t *testing.T) {
 	}
 }
 
-func waitForMessage(api *PublicWhisperAPI, id uint32, target int) bool {
+func waitForMessage(api *PublicWhisperAPI, id string, target int) bool {
 	for i := 0; i < 64; i++ {
 		all := api.GetMessages(id)
 		if len(all) >= target {

whisper/whisperv5/filter.go

@@ -18,6 +18,8 @@ package whisperv5
 
 import (
 	"crypto/ecdsa"
+	crand "crypto/rand"
+	"fmt"
 	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -39,20 +41,45 @@ type Filter struct {
 }
 
 type Filters struct {
-	id       uint32 // can contain any value except zero
-	watchers map[uint32]*Filter
+	watchers map[string]*Filter
 	whisper  *Whisper
 	mutex    sync.RWMutex
 }
 
 func NewFilters(w *Whisper) *Filters {
 	return &Filters{
-		watchers: make(map[uint32]*Filter),
+		watchers: make(map[string]*Filter),
 		whisper:  w,
 	}
 }
 
-func (fs *Filters) Install(watcher *Filter) uint32 {
+func (fs *Filters) generateRandomID() (id string) {
+	var err error
+	buf := make([]byte, 20)
+	for i := 0; i < 3; i++ {
+		_, err = crand.Read(buf)
+		if err != nil {
+			continue
+		}
+		if !validateSymmetricKey(buf) {
+			err = fmt.Errorf("error in generateRandomID: crypto/rand failed to generate random data")
+			continue
+		}
+		id = common.Bytes2Hex(buf)
+		if fs.watchers[id] != nil {
+			err = fmt.Errorf("error in generateRandomID: generated same ID twice")
+			continue
+		}
+		return id
+	}
+
+	// at this point all the attempts to generate the random ID failed.
+	// this poses a serious danger, since whisper very much relies
+	// on random numbers. the program must be terminated.
+	panic(err)
+}
+
+func (fs *Filters) Install(watcher *Filter) string {
 	if watcher.Messages == nil {
 		watcher.Messages = make(map[common.Hash]*ReceivedMessage)
 	}
@@ -60,21 +87,21 @@ func (fs *Filters) Install(watcher *Filter) uint32 {
 	fs.mutex.Lock()
 	defer fs.mutex.Unlock()
 
-	fs.id++
-	fs.watchers[fs.id] = watcher
-	return fs.id
+	id := fs.generateRandomID()
+	fs.watchers[id] = watcher
+	return id
 }
 
-func (fs *Filters) Uninstall(id uint32) {
+func (fs *Filters) Uninstall(id string) {
 	fs.mutex.Lock()
 	defer fs.mutex.Unlock()
 	delete(fs.watchers, id)
 }
 
-func (fs *Filters) Get(i uint32) *Filter {
+func (fs *Filters) Get(id string) *Filter {
 	fs.mutex.RLock()
 	defer fs.mutex.RUnlock()
-	return fs.watchers[i]
+	return fs.watchers[id]
 }
 
 func (fs *Filters) NotifyWatchers(env *Envelope, p2pMessage bool) {

whisper/whisperv5/filter_test.go

@@ -43,7 +43,7 @@ func InitDebugTest(i int64) {
 
 type FilterTestCase struct {
 	f      *Filter
-	id     uint32
+	id     string
 	alive  bool
 	msgCnt int
 }
@@ -100,14 +100,13 @@ func TestInstallFilters(t *testing.T) {
 	filters := NewFilters(w)
 	tst := generateTestCases(t, SizeTestFilters)
 
-	var j uint32
+	var j string
 	for i := 0; i < SizeTestFilters; i++ {
 		j = filters.Install(tst[i].f)
 		tst[i].id = j
-	}
-
-	if j < SizeTestFilters-1 {
-		t.Fatalf("seed %d: wrong index %d", seed, j)
+		if len(j) != 40 {
+			t.Fatalf("seed %d: wrong filter id size [%d]", seed, len(j))
+		}
 	}
 
 	for _, testCase := range tst {
@@ -519,17 +518,21 @@ func TestWatchers(t *testing.T) {
 	var i int
 	var j uint32
 	var e *Envelope
+	var x, firstID string
 
 	w := New()
 	filters := NewFilters(w)
 	tst := generateTestCases(t, NumFilters)
 	for i = 0; i < NumFilters; i++ {
 		tst[i].f.Src = nil
-		j = filters.Install(tst[i].f)
-		tst[i].id = j
+		x = filters.Install(tst[i].f)
+		tst[i].id = x
+		if len(firstID) == 0 {
+			firstID = x
+		}
 	}
 
-	last := j
+	lastID := x
 
 	var envelopes [NumMessages]*Envelope
 	for i = 0; i < NumMessages; i++ {
@@ -571,9 +574,9 @@ func TestWatchers(t *testing.T) {
 	// another round with a cloned filter
 
 	clone := cloneFilter(tst[0].f)
-	filters.Uninstall(last)
+	filters.Uninstall(lastID)
 	total = 0
-	last = NumFilters - 1
+	last := NumFilters - 1
 	tst[last].f = clone
 	filters.Install(clone)
 	for i = 0; i < NumFilters; i++ {
@@ -640,7 +643,7 @@ func TestWatchers(t *testing.T) {
 		t.Fatalf("failed with seed %d: total: got %d, want 0.", seed, total)
 	}
 
-	f := filters.Get(1)
+	f := filters.Get(firstID)
 	if f == nil {
 		t.Fatalf("failed to get the filter with seed %d.", seed)
 	}

whisper/whisperv5/peer_test.go

@@ -79,7 +79,7 @@ type TestNode struct {
 	shh     *Whisper
 	id      *ecdsa.PrivateKey
 	server  *p2p.Server
-	filerId uint32
+	filerId string
 }
 
 var result TestData

whisper/whisperv5/whisper.go

@@ -272,16 +272,16 @@ func (w *Whisper) GetSymKey(name string) []byte {
 
 // Watch installs a new message handler to run in case a matching packet arrives
 // from the whisper network.
-func (w *Whisper) Watch(f *Filter) uint32 {
+func (w *Whisper) Watch(f *Filter) string {
 	return w.filters.Install(f)
 }
 
-func (w *Whisper) GetFilter(id uint32) *Filter {
+func (w *Whisper) GetFilter(id string) *Filter {
 	return w.filters.Get(id)
 }
 
 // Unwatch removes an installed message handler.
-func (w *Whisper) Unwatch(id uint32) {
+func (w *Whisper) Unwatch(id string) {
 	w.filters.Uninstall(id)
 }
 
@@ -575,7 +575,7 @@ func (w *Whisper) Envelopes() []*Envelope {
 }
 
 // Messages retrieves all the decrypted messages matching a filter id.
-func (w *Whisper) Messages(id uint32) []*ReceivedMessage {
+func (w *Whisper) Messages(id string) []*ReceivedMessage {
 	result := make([]*ReceivedMessage, 0)
 	w.poolMu.RLock()
 	defer w.poolMu.RUnlock()

whisper/whisperv5/whisper_test.go

@@ -44,7 +44,7 @@ func TestWhisperBasic(t *testing.T) {
 	if uint64(w.Version()) != ProtocolVersion {
 		t.Fatalf("failed whisper Version: %v.", shh.Version)
 	}
-	if w.GetFilter(0) != nil {
+	if w.GetFilter("non-existent") != nil {
 		t.Fatalf("failed GetFilter.")
 	}
 
@@ -69,7 +69,7 @@ func TestWhisperBasic(t *testing.T) {
 	if len(mail) != 0 {
 		t.Fatalf("failed w.Envelopes().")
 	}
-	m := w.Messages(0)
+	m := w.Messages("non-existent")
 	if len(m) != 0 {
 		t.Fatalf("failed w.Messages.")
 	}