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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) {
var key []byte
switch c2 := c.(type) {
case *StupidGCM:
c2.Wipe()
key = c2.key
case *stupidChacha20poly1305:
c2.Wipe()
key = c2.key
default:
t.Fatalf("BUG: unhandled type %t", c2)
}
if key != nil {
t.Fatal("key is not nil")
}
}
// 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
}
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