From c537f79ccce9315d9438a2b1e182186941b57070 Mon Sep 17 00:00:00 2001
From: eater <=@eater.me>
Date: Sun, 11 Aug 2019 15:14:20 +0200
Subject: [PATCH] Add padding processing

---
 crypto.go | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/crypto.go b/crypto.go
index 0b08bcc..0b24f7a 100644
--- a/crypto.go
+++ b/crypto.go
@@ -43,7 +43,7 @@ func DecryptAndVerify(input []byte, key *rsa.PrivateKey, pub *rsa.PublicKey, sig
 	body := make([]byte, len(encBody))
 	dec := cipher2.NewCBCDecrypter(cipher, iv)
 	dec.CryptBlocks(body, encBody)
-	err = json.Unmarshal(body, v)
+	err = json.Unmarshal(unpad(body), v)
 
 	if err != nil {
 		return err
@@ -111,7 +111,54 @@ func EncryptAndSign(v interface{}, key *rsa.PrivateKey, pub *rsa.PublicKey, sign
 	encBody := make([]byte, len(body))
 	enc := cipher2.NewCBCEncrypter(cipher, iv)
 	enc.CryptBlocks(encBody, body)
+
+	copy(pad(encBody), encBody[len(encBody):])
 	writer.Write([]byte(hex.EncodeToString(encBody)))
 
 	return nil
 }
+
+func pad(body []byte) []byte {
+	rest := len(body) % 8
+	if rest == 0 {
+		padLen := getPad(body)
+		if padLen != 0 {
+			return []byte{8, 8, 8, 8, 8, 8, 8, 8}
+		}
+
+		return []byte{}
+	}
+
+	pad := make([]byte, rest)
+
+	for i := 0; i < rest; i++ {
+		pad[i] = byte(rest)
+	}
+
+	return pad
+}
+
+func getPad(body []byte) int {
+	lastIndex := len(body) - 1
+	padLen := body[lastIndex]
+	if 1 < padLen && padLen < 9 {
+		isPadding := true
+
+		for i := byte(0); i < padLen; i++ {
+			if body[-i] != padLen {
+				isPadding = false
+				break
+			}
+		}
+
+		if isPadding {
+			return int(padLen)
+		}
+	}
+
+	return 0
+}
+
+func unpad(body []byte) []byte {
+	return body[:len(body)-getPad(body)]
+}