support aggressive mode in auth reader

common/crypto/auth.go

@@ -158,8 +158,14 @@ func (v *AuthenticationReader) Read(b []byte) (int, error) {
 		return 0, err
 	}
 
-	nBytes := v.CopyChunk(b)
-	return nBytes, nil
+	totalBytes := v.CopyChunk(b)
+	for v.aggressive {
+		if err := v.NextChunk(); err != nil {
+			break
+		}
+		totalBytes += v.CopyChunk(b[totalBytes:])
+	}
+	return totalBytes, nil
 }
 
 type AuthenticationWriter struct {

common/crypto/auth_test.go

@@ -57,7 +57,60 @@ func TestAuthenticationReaderWriter(t *testing.T) {
 	nBytes, err = reader.Read(actualPayload)
 	assert.Error(err).IsNil()
 	assert.Int(nBytes).Equals(len(payload))
-	//assert.Bytes(actualPayload[:nBytes]).Equals(payload)
+	assert.Bytes(actualPayload[:nBytes]).Equals(payload)
+
+	_, err = reader.Read(actualPayload)
+	assert.Error(err).Equals(io.EOF)
+}
+
+func TestAuthenticationReaderWriterAggressive(t *testing.T) {
+	assert := assert.On(t)
+
+	key := make([]byte, 16)
+	rand.Read(key)
+	block, err := aes.NewCipher(key)
+	assert.Error(err).IsNil()
+
+	aead, err := cipher.NewGCM(block)
+	assert.Error(err).IsNil()
+
+	payload := make([]byte, 7*1024)
+	rand.Read(payload)
+
+	cache := buf.NewLocal(16 * 1024)
+	iv := make([]byte, 12)
+	rand.Read(iv)
+
+	writer := NewAuthenticationWriter(&AEADAuthenticator{
+		AEAD: aead,
+		NonceGenerator: &StaticBytesGenerator{
+			Content: iv,
+		},
+		AdditionalDataGenerator: &NoOpBytesGenerator{},
+	}, cache)
+
+	nBytes, err := writer.Write(payload)
+	assert.Error(err).IsNil()
+	assert.Int(nBytes).Equals(len(payload))
+	assert.Int(cache.Len()).GreaterThan(0)
+	_, err = writer.Write(payload)
+	assert.Error(err).IsNil()
+	assert.Int(nBytes).Equals(len(payload))
+	_, err = writer.Write([]byte{})
+	assert.Error(err).IsNil()
+
+	reader := NewAuthenticationReader(&AEADAuthenticator{
+		AEAD: aead,
+		NonceGenerator: &StaticBytesGenerator{
+			Content: iv,
+		},
+		AdditionalDataGenerator: &NoOpBytesGenerator{},
+	}, cache, true)
+
+	actualPayload := make([]byte, 16*1024)
+	nBytes, err = reader.Read(actualPayload)
+	assert.Error(err).IsNil()
+	assert.Int(nBytes).Equals(len(payload) * 2)
 
 	_, err = reader.Read(actualPayload)
 	assert.Error(err).Equals(io.EOF)