udpapi: Don't keep UDP API key in ecbState

Also add test to check if ECB is indeed correctly implemented.

diff --git a/udp/aes.go b/udp/aes.go
index 51beac3f3b421f03386343ca7857d99e40d7a2bf..4bacdce3a5c439e38ce1419f051c73cd9ea35b00 100755 (executable)
--- a/udp/aes.go
+++ b/udp/aes.go
@@ -8,24 +8,27 @@ import (
 
 // Yes, AniDB works in ECB mode
 type ecbState struct {
-       udpKey string
-       aes    cipher.Block
+       cipher.Block
 }
 
 func newECBState(udpKey string, salt []byte) *ecbState {
-       ecb := &ecbState{udpKey: udpKey}
-       ecb.Init(salt)
+       ecb := &ecbState{}
+       ecb.Init(udpKey, salt)
        return ecb
 }
 
-func (ecb *ecbState) Init(salt []byte) {
+func (ecb *ecbState) Init(udpKey string, salt []byte) {
        h := md5.New()
-       h.Write([]byte(ecb.udpKey))
+       h.Write([]byte(udpKey))
        h.Write(salt)
 
        key := h.Sum(nil)
 
-       ecb.aes, _ = aes.NewCipher(key)
+       b, err := aes.NewCipher(key)
+       ecb.Block = b
+       if err != nil {
+               panic(err)
+       }
 }
 
 func (ecb *ecbState) BlockSize() int {
@@ -38,21 +41,22 @@ func (ecb *ecbState) Encrypt(p []byte) (c []byte) {
        }
 
        padded := pkcs7Pad(p, aes.BlockSize)
-       c = make([]byte, 0, len(padded))
+       c = make([]byte, len(padded))
 
        for i := 0; i < len(padded); i += aes.BlockSize {
-               ecb.aes.Encrypt(c[i:i+aes.BlockSize], padded[i:i+aes.BlockSize])
+               ecb.Block.Encrypt(c[i:i+aes.BlockSize], padded[i:i+aes.BlockSize])
        }
        return c
 }
 
-func (ecb *ecbState) Decrypt(c []byte) (p []byte) {
+func (ecb *ecbState) Decrypt(c []byte) []byte {
        if ecb == nil {
                return c
        }
 
-       for i := 0; i < len(c); i += ecb.aes.BlockSize() {
-               ecb.aes.Decrypt(p[i:], c[i:])
+       p := make([]byte, len(c))
+       for i := 0; i < len(c); i += aes.BlockSize {
+               ecb.Block.Decrypt(p[i:i+aes.BlockSize], c[i:i+aes.BlockSize])
        }
        return pkcs7Unpad(p, aes.BlockSize)
 }

diff --git a/udp/aes_test.go b/udp/aes_test.go
index 9b7dff23daffab40fa88ad56e8fdcfd615e1f379..ddd7c6a8e7102c0a46d72f7514a0a939857f1b14 100755 (executable)
--- a/udp/aes_test.go
+++ b/udp/aes_test.go
@@ -1,10 +1,41 @@
 package udpapi
 
 import (
+       "math/rand"
+       "reflect"
        "testing"
 )
 
+func TestECB(T *testing.T) {
+       T.Parallel()
+
+       rnd := rand.New(rand.NewSource(31415))
+
+       salt := make([]byte, rnd.Intn(64))
+       for i := range salt {
+               salt[i] = byte(rnd.Intn(255))
+       }
+       plain := make([]byte, 1200+rnd.Intn(200))
+       for i := range plain {
+               plain[i] = byte(rnd.Intn(255))
+       }
+
+       ecbState := newECBState("agaa", salt)
+
+       T.Log("Length of plaintext:", len(plain))
+       cipher := ecbState.Encrypt(plain)
+       T.Log("Length of ciphertext:", len(cipher))
+       plain2 := ecbState.Decrypt(cipher)
+       T.Log("Length of roundtrip plaintext:", len(plain2))
+
+       if !reflect.DeepEqual(plain, plain2) {
+               T.Error("Encoding roundtrip result doesn't match plaintext")
+       }
+}
+
 func TestPKCS7(T *testing.T) {
+       T.Parallel()
+
        blockSize := byte(4)
        vec := [][2]string{
                [2]string{"testing", "testing\x01"},