Merge pull request #34 from dvsekhvalnov/issue-33-deflate-limit

Issue 33 deflate limit

.github/workflows/go.yml

@@ -0,0 +1,32 @@
+name: Build and test jose2go project 
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+
+  build-and-test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-latest, macos-latest]
+        version: ['1.20', '1.21', '1.22']
+    steps:
+    - name: Checkout library sources
+      uses: actions/checkout@v3
+
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version: ${{ matrix.version }}
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test ./...
+

README.md

@@ -15,6 +15,8 @@ Extensively unit tested and cross tested (100+ tests) for compatibility with [jo
 Used in production. GA ready. Current version is 1.6.
 
 ## Important
+v1.7 introduced deflate decompression memory limits to avoid denial-of-service attacks aka 'deflate-bomb'. See [Customizing compression](#customizing-compression) section for details.
+
 v1.6 security tuning options
 
 v1.5 bug fix release
@@ -997,7 +999,21 @@ test, headers, err := Decode(token, func(headers map[string]interface{}, payload
 })
 ```
 
+### Customizing compression
+There were denial-of-service attacks reported on JWT libraries that supports deflate compression by constructing malicious payload that explodes in terms of RAM on decompression. See for details: [#33](https://github.com/dvsekhvalnov/jose2go/issues/33)
+
+As of v1.7.0 `jose2go` limits decompression buffer to 250Kb to limit memory consumption and additionaly provides a way to adjust the limit according to specific scenarios:
+
+```Go
+    // Override compression alg with new limits (10Kb example)
+    jose.RegisterJwc(RegisterJwc(NewDeflate(10240)))
+```
+
 ## Changelog
+### 1.7
+- 250Kb limit on decompression buffer
+- ability to register deflate compressor with custom limits
+
 ### 1.6
 - ability to deregister specific algorithms
 - configurable min/max restrictions for PBES2-HS256+A128KW, PBES2-HS384+A192KW, PBES2-HS512+A256KW

deflate.go

@@ -3,37 +3,71 @@ package jose
 import (
 	"bytes"
 	"compress/flate"
-	"io/ioutil"
+	"errors"
+	"io"
 )
 
+var ErrSizeExceeded = errors.New("Deflate stream size exceeded limit.")
+
 func init() {
-	RegisterJwc(new(Deflate))
+	// 250Kb limited decompression buffer
+	RegisterJwc(NewDeflate(250 * 1024))
 }
 
 // Deflate compression algorithm implementation
-type Deflate struct {}
+type Deflate struct {
+	maxBufferSizeBytes int64
+}
+
+func NewDeflate(maxBufferSizeBytes int64) JwcAlgorithm {
+	return &Deflate{
+		maxBufferSizeBytes: maxBufferSizeBytes,
+	}
+}
 
 func (alg *Deflate) Name() string {
 	return DEF
 }
 
 func (alg *Deflate) Compress(plainText []byte) []byte {
 	var buf bytes.Buffer
-	deflate,_ := flate.NewWriter(&buf, 8) //level=DEFLATED
-	
+	deflate, _ := flate.NewWriter(&buf, 8) //level=DEFLATED
+
 	deflate.Write(plainText)
 	deflate.Close()
-	
+
 	return buf.Bytes()
 }
 
-func (alg *Deflate) Decompress(compressedText []byte) []byte {	
-
-	enflated,_ := ioutil.ReadAll(
-					flate.NewReader(
-						bytes.NewReader(compressedText)))
-	
-	return enflated
+func (alg *Deflate) Decompress(compressedText []byte) ([]byte, error) {
+	enflated, err := io.ReadAll(
+		newMaxBytesReader(alg.maxBufferSizeBytes,
+			flate.NewReader(
+				bytes.NewReader(compressedText))))
+
+	return enflated, err
 }
 
+// Max bytes reader
+type maxBytesReader struct {
+	reader io.Reader
+	limit  int64
+}
+
+func newMaxBytesReader(limit int64, r io.Reader) io.Reader {
+	return &maxBytesReader{reader: r, limit: limit}
+}
 
+func (mbr *maxBytesReader) Read(p []byte) (n int, err error) {
+	if mbr.limit <= 0 {
+		return 0, ErrSizeExceeded
+	}
+
+	if int64(len(p)) > mbr.limit {
+		p = p[0:mbr.limit]
+	}
+
+	n, err = mbr.reader.Read(p)
+	mbr.limit -= int64(n)
+	return
+}

jose.go

@@ -140,7 +140,7 @@ type JwsAlgorithm interface {
 // JwcAlgorithm is a contract for implementing compression algorithm
 type JwcAlgorithm interface {
 	Compress(plainText []byte) []byte
-	Decompress(compressedText []byte) []byte
+	Decompress(compressedText []byte) ([]byte, error)
 	Name() string
 }
 
@@ -427,7 +427,9 @@ func decrypt(parts [][]byte, key interface{}) (plainText []byte, headers map[str
 							return nil, nil, errors.New(fmt.Sprintf("jwt.decrypt(): Unknown compression algorithm '%v'", zip))
 						}
 
-						plainBytes = zipAlg.Decompress(plainBytes)
+						if plainBytes, err = zipAlg.Decompress(plainBytes); err != nil {
+							return nil, nil, err
+						}
 					}
 
 					return plainBytes, jwtHeader, nil

sec_test/security_vulnerabilities_test.go

@@ -2,12 +2,18 @@ package sec_test
 
 import (
 	"crypto/ecdsa"
+	"crypto/rsa"
+	"encoding/json"
 	"fmt"
-	"github.com/dvsekhvalnov/jose2go"
+	"strings"
+	"testing"
+	"time"
+
+	jose "github.com/dvsekhvalnov/jose2go"
 	"github.com/dvsekhvalnov/jose2go/arrays"
 	"github.com/dvsekhvalnov/jose2go/keys/ecc"
+	Rsa "github.com/dvsekhvalnov/jose2go/keys/rsa"
 	. "gopkg.in/check.v1"
-	"testing"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -93,8 +99,89 @@ func (s *SecurityTestSuite) Test_AAD_IntegerOverflow(c *C) {
 	c.Assert(test, IsNil)
 }
 
+func (s *SecurityTestSuite) Test_DeflateBomb(c *C) {
+	strU := strings.Repeat("U", 400000000)
+	strUU := strings.Repeat("U", 100000000)
+
+	payloadMap := map[string]string{
+		"U":  strU,
+		"UU": strUU,
+	}
+
+	payloadBytes, _ := json.Marshal(payloadMap)
+
+	fmt.Println("Uncompressed payload length", len(payloadBytes))
+	test, _ := jose.Encrypt(string(payloadBytes), jose.RSA_OAEP, jose.A256GCM, PubKey(), jose.Zip(jose.DEF))
+	fmt.Println("Encoded & Compressed token length", len(test))
+
+	start := time.Now()
+	payload, headers, err := jose.Decode(test, PrivKey())
+	timeElapsed := time.Since(start)
+	fmt.Printf("The `decode` took %s\n", timeElapsed)
+
+	c.Assert(payload, Equals, "")
+	c.Assert(headers, IsNil)
+	c.Assert(err, Equals, jose.ErrSizeExceeded)
+}
+
 func Ecc256() *ecdsa.PrivateKey {
 	return ecc.NewPrivate([]byte{193, 227, 73, 203, 97, 236, 112, 36, 140, 232, 1, 3, 76, 56, 52, 225, 184, 142, 190, 17, 97, 203, 37, 175, 56, 116, 31, 120, 95, 207, 196, 196},
 		[]byte{123, 201, 103, 8, 239, 128, 149, 43, 83, 248, 210, 85, 95, 231, 43, 132, 30, 208, 69, 136, 98, 139, 29, 55, 138, 89, 73, 57, 80, 14, 201, 201},
 		[]byte{84, 73, 131, 102, 144, 215, 92, 175, 41, 240, 221, 2, 157, 219, 49, 179, 221, 184, 171, 169, 210, 213, 21, 197, 1, 36, 101, 232, 23, 212, 169, 220})
 }
+
+func PubKey() *rsa.PublicKey {
+	key, _ := Rsa.ReadPublic([]byte(pubKey))
+	return key
+}
+
+func PrivKey() *rsa.PrivateKey {
+	key, _ := Rsa.ReadPrivate([]byte(privKey))
+	return key
+}
+
+var pubKey = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+var privKey = `-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`