1// Copyright 2017 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package crypto
6
7import (
8	"crypto/aes"
9	"crypto/cipher"
10	"crypto/rc4"
11	"testing"
12)
13
14func TestRC4OutOfBoundsWrite(t *testing.T) {
15	// This cipherText is encrypted "0123456789"
16	cipherText := []byte{238, 41, 187, 114, 151, 2, 107, 13, 178, 63}
17	cipher, err := rc4.NewCipher([]byte{0})
18	if err != nil {
19		panic(err)
20	}
21	test(t, "RC4", cipherText, cipher.XORKeyStream)
22}
23func TestCTROutOfBoundsWrite(t *testing.T) {
24	testBlock(t, "CTR", cipher.NewCTR)
25}
26func TestOFBOutOfBoundsWrite(t *testing.T) {
27	testBlock(t, "OFB", cipher.NewOFB)
28}
29func TestCFBEncryptOutOfBoundsWrite(t *testing.T) {
30	testBlock(t, "CFB Encrypt", cipher.NewCFBEncrypter)
31}
32func TestCFBDecryptOutOfBoundsWrite(t *testing.T) {
33	testBlock(t, "CFB Decrypt", cipher.NewCFBDecrypter)
34}
35func testBlock(t *testing.T, name string, newCipher func(cipher.Block, []byte) cipher.Stream) {
36	// This cipherText is encrypted "0123456789"
37	cipherText := []byte{86, 216, 121, 231, 219, 191, 26, 12, 176, 117}
38	var iv, key [16]byte
39	block, err := aes.NewCipher(key[:])
40	if err != nil {
41		panic(err)
42	}
43	stream := newCipher(block, iv[:])
44	test(t, name, cipherText, stream.XORKeyStream)
45}
46func test(t *testing.T, name string, cipherText []byte, xor func([]byte, []byte)) {
47	want := "abcdefghij"
48	plainText := []byte(want)
49	shorterLen := len(cipherText) / 2
50	defer func() {
51		err := recover()
52		if err == nil {
53			t.Errorf("%v XORKeyStream expected to panic on len(dst) < len(src), but didn't", name)
54		}
55		const plain = "0123456789"
56		if plainText[shorterLen] == plain[shorterLen] {
57			t.Errorf("%v XORKeyStream did out of bounds write, want %v, got %v", name, want, string(plainText))
58		}
59	}()
60	xor(plainText[:shorterLen], cipherText)
61}
62