Update to Cloak 2.10.0

.github/workflows/build.yml

@@ -7,11 +7,85 @@ jobs:
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-go@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
         with:
           go-version: '^1.22' # The Go version to download (if necessary) and use.
       - run: go test -race -coverprofile coverage.txt -coverpkg ./... -covermode atomic ./...
-      - uses: codecov/codecov-action@v1
+      - uses: codecov/codecov-action@v4
         with:
-          file: coverage.txt
+          files: coverage.txt
+          token: ${{ secrets.CODECOV_TOKEN }}
+
+  compat-test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        encryption-method: [ plain, chacha20-poly1305 ]
+        num-conn: [ 0, 1, 4 ]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '^1.22'
+      - name: Build Cloak
+        run: make
+      - name: Create configs
+        run: |
+          mkdir config
+          cat << EOF > config/ckclient.json
+            {
+              "Transport": "direct",
+              "ProxyMethod": "iperf",
+              "EncryptionMethod": "${{ matrix.encryption-method }}",
+              "UID": "Q4GAXHVgnDLXsdTpw6bmoQ==",
+              "PublicKey": "4dae/bF43FKGq+QbCc5P/E/MPM5qQeGIArjmJEHiZxc=",
+              "ServerName": "cloudflare.com",
+              "BrowserSig": "firefox",
+              "NumConn": ${{ matrix.num-conn }}
+            }
+          EOF
+          cat << EOF > config/ckserver.json
+            {
+              "ProxyBook": {
+                "iperf": [
+                  "tcp",
+                  "127.0.0.1:5201"
+                ]
+              },
+              "BindAddr": [
+                ":8443"
+              ],
+              "BypassUID": [
+                "Q4GAXHVgnDLXsdTpw6bmoQ=="
+              ],
+              "RedirAddr": "cloudflare.com",
+              "PrivateKey": "AAaskZJRPIAbiuaRLHsvZPvE6gzOeSjg+ZRg1ENau0Y="
+            }
+          EOF
+      - name: Start iperf3 server
+        run: docker run -d --name iperf-server --network host ajoergensen/iperf3:latest --server
+      - name: Test new client against old server
+        run: |
+          docker run -d --name old-cloak-server --network host -v $PWD/config:/go/Cloak/config cbeuw/cloak:latest build/ck-server -c config/ckserver.json --verbosity debug
+          build/ck-client -c config/ckclient.json -s 127.0.0.1 -p 8443 --verbosity debug | tee new-cloak-client.log &
+          docker run --network host ajoergensen/iperf3:latest --client 127.0.0.1 -p 1984
+          docker stop old-cloak-server
+      - name: Test old client against new server
+        run: |
+          build/ck-server -c config/ckserver.json --verbosity debug | tee new-cloak-server.log &
+          docker run -d --name old-cloak-client --network host -v $PWD/config:/go/Cloak/config cbeuw/cloak:latest build/ck-client -c config/ckclient.json -s 127.0.0.1 -p 8443 --verbosity debug
+          docker run --network host ajoergensen/iperf3:latest --client 127.0.0.1 -p 1984
+          docker stop old-cloak-client
+      - name: Dump docker logs
+        if: always()
+        run: |
+          docker container logs iperf-server > iperf-server.log
+          docker container logs old-cloak-server > old-cloak-server.log
+          docker container logs old-cloak-client > old-cloak-client.log
+      - name: Upload logs
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.encryption-method }}-${{ matrix.num-conn }}-conn-logs
+          path: ./*.log

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Build
         run: |
           export PATH=${PATH}:`go env GOPATH`/bin
@@ -19,4 +19,32 @@ jobs:
         with:
           files: release/*
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  build-docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            cbeuw/cloak
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -0,0 +1,5 @@
+FROM golang:latest
+
+RUN git clone https://github.com/cbeuw/Cloak.git
+WORKDIR Cloak
+RUN make

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/gorilla/mux v1.8.1
 	github.com/gorilla/websocket v1.5.1
 	github.com/juju/ratelimit v1.0.2
-	github.com/refraction-networking/utls v1.6.4
+	github.com/refraction-networking/utls v1.6.6
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.9.0
 	go.etcd.io/bbolt v1.3.9
@@ -23,7 +23,7 @@ require (
 	github.com/klauspost/compress v1.17.4 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/net v0.21.0 // indirect
+	golang.org/x/net v0.23.0 // indirect
 	golang.org/x/sys v0.19.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -25,6 +25,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/refraction-networking/utls v1.6.4 h1:aeynTroaYn7y+mFtqv8D0bQ4bw0y9nJHneGxJ7lvRDM=
 github.com/refraction-networking/utls v1.6.4/go.mod h1:2VL2xfiqgFAZtJKeUTlf+PSYFs3Eu7km0gCtXJ3m8zs=
+github.com/refraction-networking/utls v1.6.6 h1:igFsYBUJPYM8Rno9xUuDoM5GQrVEqY4llzEXOkL43Ig=
+github.com/refraction-networking/utls v1.6.6/go.mod h1:BC3O4vQzye5hqpmDTWUqi4P5DDhzJfkV1tdqtawQIH0=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
@@ -39,6 +41,8 @@ golang.org/x/crypto v0.22.0 h1:g1v0xeRhjcugydODzvb3mEM9SQ0HGp9s/nh3COQ/C30=
 golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
+golang.org/x/net v0.23.0 h1:7EYJ93RZ9vYSZAIb2x3lnuvqO5zneoD6IvWjuhfxjTs=
+golang.org/x/net v0.23.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
 golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
 golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

internal/multiplex/obfs.go

@@ -3,10 +3,10 @@ package multiplex
 import (
 	"crypto/aes"
 	"crypto/cipher"
+	"crypto/rand"
 	"encoding/binary"
 	"errors"
 	"fmt"
-
 	"github.com/cbeuw/Cloak/internal/common"
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/salsa20"
@@ -15,6 +15,14 @@ import (
 const frameHeaderLength = 14
 const salsa20NonceSize = 8
 
+// maxExtraLen equals the max length of padding + AEAD tag.
+// It is 255 bytes because the extra len field in frame header is only one byte.
+const maxExtraLen = 1<<8 - 1
+
+// padFirstNFrames specifies the number of initial frames to pad,
+// to avoid TLS-in-TLS detection
+const padFirstNFrames = 5
+
 const (
 	EncryptionMethodPlain = iota
 	EncryptionMethodAES256GCM
@@ -27,8 +35,6 @@ type Obfuscator struct {
 	payloadCipher cipher.AEAD
 
 	sessionKey [32]byte
-
-	maxOverhead int
 }
 
 // obfuscate adds multiplexing headers, encrypt and add TLS header
@@ -49,45 +55,34 @@ func (o *Obfuscator) obfuscate(f *Frame, buf []byte, payloadOffsetInBuf int) (in
 	// to be large enough that they may never happen in reasonable time frames. Of course, different sessions
 	// will produce the same combination of stream id and frame sequence, but they will have different session keys.
 	//
-	// Salsa20 is assumed to be given a unique nonce each time because we assume the tags produced by payloadCipher
-	// AEAD is unique each time, as payloadCipher itself is given a unique iv/nonce each time due to points made above.
-	// This is relatively a weak guarantee as we are assuming AEADs to produce different tags given different iv/nonces.
-	// This is almost certainly true but I cannot find a source that outright states this.
 	//
 	// Because the frame header, before it being encrypted, is fed into the AEAD, it is also authenticated.
 	// (rfc5116 s.2.1 "The nonce is authenticated internally to the algorithm").
 	//
 	// In case the user chooses to not encrypt the frame payload, payloadCipher will be nil. In this scenario,
-	// we pad the frame payload with random bytes until it reaches Salsa20's nonce size (8 bytes). Then we simply
-	// encrypt the frame header with the last 8 bytes of frame payload as nonce.
-	// If the payload provided by the user is greater than 8 bytes, then we use entirely the user input as nonce.
-	// We can't ensure its uniqueness ourselves, which is why plaintext mode must only be used when the user input
-	// is already random-like. For Cloak it would normally mean that the user is using a proxy protocol that sends
-	// encrypted data.
+	// we generate random bytes to be used as salsa20 nonce.
 	payloadLen := len(f.Payload)
 	if payloadLen == 0 {
 		return 0, errors.New("payload cannot be empty")
 	}
-	var extraLen int
-	if o.payloadCipher == nil {
-		extraLen = salsa20NonceSize - payloadLen
-		if extraLen < 0 {
-			// if our payload is already greater than 8 bytes
-			extraLen = 0
-		}
+	tagLen := 0
+	if o.payloadCipher != nil {
+		tagLen = o.payloadCipher.Overhead()
 	} else {
-		extraLen = o.payloadCipher.Overhead()
-		if extraLen < salsa20NonceSize {
-			return 0, errors.New("AEAD's Overhead cannot be fewer than 8 bytes")
-		}
+		tagLen = salsa20NonceSize
+	}
+	// Pad to avoid size side channel leak
+	padLen := 0
+	if f.Seq < padFirstNFrames {
+		padLen = common.RandInt(maxExtraLen - tagLen + 1)
 	}
 
-	usefulLen := frameHeaderLength + payloadLen + extraLen
+	usefulLen := frameHeaderLength + payloadLen + padLen + tagLen
 	if len(buf) < usefulLen {
 		return 0, errors.New("obfs buffer too small")
 	}
 	// we do as much in-place as possible to save allocation
-	payload := buf[frameHeaderLength : frameHeaderLength+payloadLen]
+	payload := buf[frameHeaderLength : frameHeaderLength+payloadLen+padLen]
 	if payloadOffsetInBuf != frameHeaderLength {
 		// if payload is not at the correct location in buffer
 		copy(payload, f.Payload)
@@ -97,14 +92,15 @@ func (o *Obfuscator) obfuscate(f *Frame, buf []byte, payloadOffsetInBuf int) (in
 	binary.BigEndian.PutUint32(header[0:4], f.StreamID)
 	binary.BigEndian.PutUint64(header[4:12], f.Seq)
 	header[12] = f.Closing
-	header[13] = byte(extraLen)
+	header[13] = byte(padLen + tagLen)
 
-	if o.payloadCipher == nil {
-		if extraLen != 0 { // read nonce
-			extra := buf[usefulLen-extraLen : usefulLen]
-			common.CryptoRandRead(extra)
-		}
-	} else {
+	// Random bytes for padding and nonce
+	_, err := rand.Read(buf[frameHeaderLength+payloadLen : usefulLen])
+	if err != nil {
+		return 0, fmt.Errorf("failed to pad random: %w", err)
+	}
+
+	if o.payloadCipher != nil {
 		o.payloadCipher.Seal(payload[:0], header[:o.payloadCipher.NonceSize()], payload, nil)
 	}
 
@@ -166,7 +162,6 @@ func MakeObfuscator(encryptionMethod byte, sessionKey [32]byte) (o Obfuscator, e
 	switch encryptionMethod {
 	case EncryptionMethodPlain:
 		o.payloadCipher = nil
-		o.maxOverhead = salsa20NonceSize
 	case EncryptionMethodAES256GCM:
 		var c cipher.Block
 		c, err = aes.NewCipher(sessionKey[:])
@@ -177,7 +172,6 @@ func MakeObfuscator(encryptionMethod byte, sessionKey [32]byte) (o Obfuscator, e
 		if err != nil {
 			return
 		}
-		o.maxOverhead = o.payloadCipher.Overhead()
 	case EncryptionMethodAES128GCM:
 		var c cipher.Block
 		c, err = aes.NewCipher(sessionKey[:16])
@@ -188,13 +182,11 @@ func MakeObfuscator(encryptionMethod byte, sessionKey [32]byte) (o Obfuscator, e
 		if err != nil {
 			return
 		}
-		o.maxOverhead = o.payloadCipher.Overhead()
 	case EncryptionMethodChaha20Poly1305:
 		o.payloadCipher, err = chacha20poly1305.New(sessionKey[:])
 		if err != nil {
 			return
 		}
-		o.maxOverhead = o.payloadCipher.Overhead()
 	default:
 		return o, fmt.Errorf("unknown encryption method valued %v", encryptionMethod)
 	}