Add fuzz tests for ccm

pkg/crypto/ciphersuite/ccm_test.go

@@ -0,0 +1,106 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package ciphersuite
+
+import (
+	"crypto/aes"
+	"encoding/binary"
+	"testing"
+
+	"github.com/pion/dtls/v3/pkg/protocol"
+	"github.com/pion/dtls/v3/pkg/protocol/recordlayer"
+	"github.com/stretchr/testify/assert"
+)
+
+func FuzzCCM_EncryptDecrypt_RoundTrip(f *testing.F) {
+	f.Add(byte(8), []byte{1, 2, 3, 4, 5}, uint16(0), uint64(0))
+	f.Add(byte(16), []byte{}, uint16(1), uint64(7))
+	f.Add(byte(8), make([]byte, 64), uint16(3), uint64(42))
+
+	f.Fuzz(func(t *testing.T, tagLenByte byte, payload []byte, epoch uint16, seq uint64) {
+		tag := CCMTagLength8
+		if tagLenByte%2 == 0 {
+			tag = CCMTagLength
+		}
+
+		key := make([]byte, 16)
+		for i := range key {
+			var b byte
+
+			if i < len(payload) {
+				b = payload[i]
+			} else {
+				b = byte(i*31 + 7)
+			}
+
+			key[i] = b
+		}
+
+		var tmp8 [8]byte
+		x := seq ^ 0xA5A5A5A5A5A5A5A5
+		binary.BigEndian.PutUint64(tmp8[:], x)
+		iv := append([]byte(nil), tmp8[4:]...)
+
+		ccm, err := NewCCM(tag, key, iv, key, iv)
+		assert.NoError(t, err)
+
+		rl := &recordlayer.RecordLayer{
+			Header: recordlayer.Header{
+				ContentType:    protocol.ContentTypeApplicationData,
+				Version:        protocol.Version1_2,
+				Epoch:          epoch,
+				SequenceNumber: seq,
+			},
+			Content: &protocol.ApplicationData{
+				Data: append([]byte(nil), payload...),
+			},
+		}
+		raw, err := rl.Marshal()
+		assert.NoError(t, err)
+
+		enc, err := ccm.Encrypt(rl, raw)
+		assert.NoError(t, err)
+
+		var hdr recordlayer.Header
+		dec, err := ccm.Decrypt(hdr, enc)
+		assert.NoError(t, err)
+
+		var out recordlayer.RecordLayer
+		assert.NoError(t, out.Unmarshal(dec))
+
+		app, ok := out.Content.(*protocol.ApplicationData)
+		assert.True(t, ok)
+		assert.Equal(t, payload, app.Data)
+	})
+}
+
+func FuzzCCM_Decrypt(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+	f.Add([]byte{})
+
+	f.Fuzz(func(t *testing.T, body []byte) {
+		recordLayer := &recordlayer.RecordLayer{
+			Header: recordlayer.Header{
+				ContentType: protocol.ContentTypeChangeCipherSpec,
+				Version:     protocol.Version1_2,
+			},
+			Content: &protocol.ChangeCipherSpec{},
+		}
+
+		raw, err := recordLayer.Marshal()
+		assert.NoError(t, err)
+		raw = append(raw, body...) // arbitrary body after the header for fuzzing
+
+		key := make([]byte, 16)
+		_, err = aes.NewCipher(key)
+		assert.NoError(t, err)
+
+		ccmAEAD, err := NewCCM(CCMTagLength8, key, []byte{0, 0, 0, 0}, key, []byte{0, 0, 0, 0})
+		assert.NoError(t, err)
+
+		out, err := ccmAEAD.Decrypt(recordlayer.Header{}, raw)
+		assert.NoError(t, err)
+		assert.Equal(t, raw, out)
+	})
+}