summaryrefslogtreecommitdiff
path: root/internal/stupidgcm/common_test.go
blob: cf555b05e283fa0d21f4e46dd67aea096e7f5f25 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
package stupidgcm

import (
	"bytes"
	"crypto/cipher"
	"crypto/rand"
	"encoding/hex"
	"log"
	"testing"
)

func testCiphers(t *testing.T, our cipher.AEAD, ref cipher.AEAD) {
	t.Run("testEncryptDecrypt", func(t *testing.T) { testEncryptDecrypt(t, our, ref) })
	t.Run("testInplaceSeal", func(t *testing.T) { testInplaceSeal(t, our, ref) })
	t.Run("testInplaceOpen", func(t *testing.T) { testInplaceOpen(t, our, ref) })
	t.Run("testCorruption_c1", func(t *testing.T) { testCorruption(t, our) })
	t.Run("testCorruption_c2", func(t *testing.T) { testCorruption(t, ref) })
	t.Run("testWipe", func(t *testing.T) { testWipe(t, our) })
}

// testEncryptDecrypt encrypts and decrypts using both stupidgcm and Go's built-in
// GCM implementation and verifies that the results are identical.
func testEncryptDecrypt(t *testing.T, c1 cipher.AEAD, c2 cipher.AEAD) {
	if c1.NonceSize() != c2.NonceSize() {
		t.Fatal("different NonceSize")
	}
	if c1.Overhead() != c2.Overhead() {
		t.Fatal("different Overhead")
	}

	authData := randBytes(24)
	iv := randBytes(c1.NonceSize())

	dst := make([]byte, 71) // 71 = arbitrary length

	// Check all block sizes from 1 to 5000
	for i := 1; i < 5000; i++ {
		in := make([]byte, i)

		c1out := c1.Seal(dst, iv, in, authData)
		c2out := c2.Seal(dst, iv, in, authData)

		// Ciphertext must be identical to Go GCM
		if !bytes.Equal(c1out, c2out) {
			t.Fatalf("Compare failed for encryption, size %d", i)
			t.Log("c1out:")
			t.Log("\n" + hex.Dump(c1out))
			t.Log("c2out:")
			t.Log("\n" + hex.Dump(c2out))
		}

		c1out2, sErr := c1.Open(dst, iv, c1out[len(dst):], authData)
		if sErr != nil {
			t.Fatal(sErr)
		}
		c2out2, gErr := c2.Open(dst, iv, c2out[len(dst):], authData)
		if gErr != nil {
			t.Fatal(gErr)
		}

		// Plaintext must be identical to Go GCM
		if !bytes.Equal(c1out2, c2out2) {
			t.Fatalf("Compare failed for decryption, size %d", i)
		}
	}
}

// Seal re-uses the "dst" buffer it is large enough.
// Check that this works correctly by testing different "dst" capacities from
// 5000 to 16 and "in" lengths from 1 to 5000.
func testInplaceSeal(t *testing.T, c1 cipher.AEAD, c2 cipher.AEAD) {
	authData := randBytes(24)
	iv := randBytes(c1.NonceSize())

	max := 5016
	// Check all block sizes from 1 to 5000
	for i := 1; i < max-16; i++ {
		in := make([]byte, i)
		dst := make([]byte, max-i)
		dst = dst[:16]

		c1out := c1.Seal(dst, iv, in, authData)
		dst2 := make([]byte, 16)
		c2out := c2.Seal(dst2, iv, in, authData)

		// Ciphertext must be identical to Go GCM
		if !bytes.Equal(c1out, c2out) {
			t.Fatalf("Compare failed for encryption, size %d", i)
			t.Log("sOut:")
			t.Log("\n" + hex.Dump(c1out))
			t.Log("gOut:")
			t.Log("\n" + hex.Dump(c2out))
		}
	}
}

// testInplaceOpen - Open re-uses the "dst" buffer it is large enough.
// Check that this works correctly by testing different "dst" capacities from
// 5000 to 16 and "in" lengths from 1 to 5000.
func testInplaceOpen(t *testing.T, c1 cipher.AEAD, c2 cipher.AEAD) {
	authData := randBytes(24)
	iv := randBytes(c1.NonceSize())

	max := 5016
	// Check all block sizes from 1 to 5000
	for i := 1; i < max-c1.NonceSize(); i++ {
		in := make([]byte, i)

		c2ciphertext := c2.Seal(iv, iv, in, authData)

		dst := make([]byte, max-i)
		// sPlaintext ... stupidgcm plaintext
		c1plaintext, err := c1.Open(dst[:0], iv, c2ciphertext[c1.NonceSize():], authData)
		if err != nil {
			t.Fatal(err)
		}

		// Plaintext must be identical to Go GCM
		if !bytes.Equal(in, c1plaintext) {
			t.Fatalf("Compare failed, i=%d", i)
		}
	}
}

// testCorruption verifies that changes in the ciphertext result in a decryption
// error
func testCorruption(t *testing.T, c cipher.AEAD) {
	authData := randBytes(24)
	iv := randBytes(c.NonceSize())

	in := make([]byte, 354)
	out := c.Seal(nil, iv, in, authData)
	out2, sErr := c.Open(nil, iv, out, authData)
	if sErr != nil {
		t.Fatal(sErr)
	}
	if !bytes.Equal(in, out2) {
		t.Fatalf("Compare failed")
	}

	// Corrupt first byte
	out[0]++
	out2, sErr = c.Open(nil, iv, out, authData)
	if sErr == nil || out2 != nil {
		t.Fatalf("Should have gotten error")
	}
	out[0]--

	// Corrupt last byte
	out[len(out)-1]++
	out2, sErr = c.Open(nil, iv, out, authData)
	if sErr == nil || out2 != nil {
		t.Fatalf("Should have gotten error")
	}
	out[len(out)-1]--

	// Append one byte
	out = append(out, 0)
	out2, sErr = c.Open(nil, iv, out, authData)
	if sErr == nil || out2 != nil {
		t.Fatalf("Should have gotten error")
	}
}

type Wiper interface {
	Wipe()
}

func testWipe(t *testing.T, c cipher.AEAD) {
	switch c2 := c.(type) {
	case *StupidGCM:
		c2.Wipe()
		if c2.key != nil {
			t.Fatal("key is not nil")
		}
	case *stupidChacha20poly1305:
		c2.Wipe()
		if !c2.wiped {
			t.Error("c2.wiped is not set")
		}
		for _, v := range c2.key {
			if v != 0 {
				t.Fatal("c2.key is not zeroed")
			}
		}
	default:
		t.Fatalf("BUG: unhandled type %t", c2)
	}
}

// Get "n" random bytes from /dev/urandom or panic
func randBytes(n int) []byte {
	b := make([]byte, n)
	_, err := rand.Read(b)
	if err != nil {
		log.Panic("Failed to read random bytes: " + err.Error())
	}
	return b
}