libgocryptfs/internal/stupidgcm/stupidgcm_test.go
Jakob Unterwurzacher ccf1a84e41 macos: make testing without openssl work properly
On MacOS, building and testing without openssl is much easier.
The tests should skip tests that fail because of missing openssl
instead of aborting.

Fixes https://github.com/rfjakob/gocryptfs/issues/123
2017-07-14 23:22:15 +02:00

196 lines
4.6 KiB
Go

// +build !without_openssl
// We compare against Go's built-in GCM implementation. Since stupidgcm only
// supports 128-bit IVs and Go only supports that from 1.5 onward, we cannot
// run these tests on older Go versions.
package stupidgcm
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/hex"
"log"
"testing"
)
// 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
}
// TestEncryptDecrypt encrypts and decrypts using both stupidgcm and Go's built-in
// GCM implemenatation and verifies that the results are identical.
func TestEncryptDecrypt(t *testing.T) {
key := randBytes(32)
sGCM := New(key, false)
authData := randBytes(24)
iv := randBytes(16)
dst := make([]byte, 71) // 71 = random length
gAES, err := aes.NewCipher(key)
if err != nil {
t.Fatal(err)
}
gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
if err != nil {
t.Fatal(err)
}
// Check all block sizes from 1 to 5000
for i := 1; i < 5000; i++ {
in := make([]byte, i)
sOut := sGCM.Seal(dst, iv, in, authData)
gOut := gGCM.Seal(dst, iv, in, authData)
// Ciphertext must be identical to Go GCM
if !bytes.Equal(sOut, gOut) {
t.Fatalf("Compare failed for encryption, size %d", i)
t.Log("sOut:")
t.Log("\n" + hex.Dump(sOut))
t.Log("gOut:")
t.Log("\n" + hex.Dump(gOut))
}
sOut2, sErr := sGCM.Open(dst, iv, sOut[len(dst):], authData)
if sErr != nil {
t.Fatal(sErr)
}
gOut2, gErr := gGCM.Open(dst, iv, gOut[len(dst):], authData)
if gErr != nil {
t.Fatal(gErr)
}
// Plaintext must be identical to Go GCM
if !bytes.Equal(sOut2, gOut2) {
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) {
key := randBytes(32)
sGCM := New(key, false)
authData := randBytes(24)
iv := randBytes(16)
gAES, err := aes.NewCipher(key)
if err != nil {
t.Fatal(err)
}
gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
if err != nil {
t.Fatal(err)
}
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]
sOut := sGCM.Seal(dst, iv, in, authData)
dst2 := make([]byte, 16)
gOut := gGCM.Seal(dst2, iv, in, authData)
// Ciphertext must be identical to Go GCM
if !bytes.Equal(sOut, gOut) {
t.Fatalf("Compare failed for encryption, size %d", i)
t.Log("sOut:")
t.Log("\n" + hex.Dump(sOut))
t.Log("gOut:")
t.Log("\n" + hex.Dump(gOut))
}
}
}
// 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) {
key := randBytes(32)
sGCM := New(key, false)
authData := randBytes(24)
iv := randBytes(16)
gAES, err := aes.NewCipher(key)
if err != nil {
t.Fatal(err)
}
gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
if err != nil {
t.Fatal(err)
}
max := 5016
// Check all block sizes from 1 to 5000
for i := 1; i < max-16; i++ {
in := make([]byte, i)
gCiphertext := gGCM.Seal(iv, iv, in, authData)
dst := make([]byte, max-i)
// sPlaintext ... stupidgcm plaintext
sPlaintext, err := sGCM.Open(dst[:0], iv, gCiphertext[16:], authData)
if err != nil {
t.Fatal(err)
}
// Plaintext must be identical to Go GCM
if !bytes.Equal(in, sPlaintext) {
t.Fatalf("Compare failed, i=%d", i)
}
}
}
// TestCorruption verifies that changes in the ciphertext result in a decryption
// error
func TestCorruption(t *testing.T) {
key := randBytes(32)
sGCM := New(key, false)
authData := randBytes(24)
iv := randBytes(16)
in := make([]byte, 354)
sOut := sGCM.Seal(nil, iv, in, authData)
sOut2, sErr := sGCM.Open(nil, iv, sOut, authData)
if sErr != nil {
t.Fatal(sErr)
}
if !bytes.Equal(in, sOut2) {
t.Fatalf("Compare failed")
}
// Corrupt first byte
sOut[0]++
sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
if sErr == nil || sOut2 != nil {
t.Fatalf("Should have gotten error")
}
sOut[0]--
// Corrupt last byte
sOut[len(sOut)-1]++
sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
if sErr == nil || sOut2 != nil {
t.Fatalf("Should have gotten error")
}
sOut[len(sOut)-1]--
// Append one byte
sOut = append(sOut, 0)
sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
if sErr == nil || sOut2 != nil {
t.Fatalf("Should have gotten error")
}
}