4 files changed, 162 insertions, 0 deletions
diff --git a/vendor/github.com/Philipp15b/go-steam/cryptoutil/cryptoutil.go b/vendor/github.com/Philipp15b/go-steam/cryptoutil/cryptoutil.go
new file mode 100644
index 00000000..b44f8d26
--- /dev/null
+++ b/vendor/github.com/Philipp15b/go-steam/cryptoutil/cryptoutil.go
@@ -0,0 +1,38 @@
+package cryptoutil
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+)
+
+// Performs an encryption using AES/CBC/PKCS7
+// with a random IV prepended using AES/ECB/None.
+func SymmetricEncrypt(ciph cipher.Block, src []byte) []byte {
+	// get a random IV and ECB encrypt it
+	iv := make([]byte, aes.BlockSize, aes.BlockSize)
+	_, err := rand.Read(iv)
+	if err != nil {
+		panic(err)
+	}
+	encryptedIv := make([]byte, aes.BlockSize, aes.BlockSize)
+	newECBEncrypter(ciph).CryptBlocks(encryptedIv, iv)
+
+	// pad it, copy the IV to the first 16 bytes and encrypt the rest with CBC
+	encrypted := padPKCS7WithIV(src)
+	copy(encrypted, encryptedIv)
+	cipher.NewCBCEncrypter(ciph, iv).CryptBlocks(encrypted[aes.BlockSize:], encrypted[aes.BlockSize:])
+	return encrypted
+}
+
+// Decrypts data from the reader using AES/CBC/PKCS7 with an IV
+// prepended using AES/ECB/None. The src slice may not be used anymore.
+func SymmetricDecrypt(ciph cipher.Block, src []byte) []byte {
+	iv := src[:aes.BlockSize]
+	newECBDecrypter(ciph).CryptBlocks(iv, iv)
+
+	data := src[aes.BlockSize:]
+	cipher.NewCBCDecrypter(ciph, iv).CryptBlocks(data, data)
+
+	return unpadPKCS7(data)
+}
diff --git a/vendor/github.com/Philipp15b/go-steam/cryptoutil/ecb.go b/vendor/github.com/Philipp15b/go-steam/cryptoutil/ecb.go
new file mode 100644
index 00000000..4298686f
--- /dev/null
+++ b/vendor/github.com/Philipp15b/go-steam/cryptoutil/ecb.go
@@ -0,0 +1,68 @@
+package cryptoutil
+
+import (
+	"crypto/cipher"
+)
+
+// From this code review: https://codereview.appspot.com/7860047/
+// by fasmat for the Go crypto/cipher package
+
+type ecb struct {
+	b         cipher.Block
+	blockSize int
+}
+
+func newECB(b cipher.Block) *ecb {
+	return &ecb{
+		b:         b,
+		blockSize: b.BlockSize(),
+	}
+}
+
+type ecbEncrypter ecb
+
+// NewECBEncrypter returns a BlockMode which encrypts in electronic code book
+// mode, using the given Block.
+func newECBEncrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbEncrypter)(newECB(b))
+}
+
+func (x *ecbEncrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("cryptoutil/ecb: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("cryptoutil/ecb: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Encrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+type ecbDecrypter ecb
+
+// newECBDecrypter returns a BlockMode which decrypts in electronic code book
+// mode, using the given Block.
+func newECBDecrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbDecrypter)(newECB(b))
+}
+
+func (x *ecbDecrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("cryptoutil/ecb: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("cryptoutil/ecb: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Decrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
diff --git a/vendor/github.com/Philipp15b/go-steam/cryptoutil/pkcs7.go b/vendor/github.com/Philipp15b/go-steam/cryptoutil/pkcs7.go
new file mode 100644
index 00000000..8200fb94
--- /dev/null
+++ b/vendor/github.com/Philipp15b/go-steam/cryptoutil/pkcs7.go
@@ -0,0 +1,25 @@
+package cryptoutil
+
+import (
+	"crypto/aes"
+)
+
+// Returns a new byte array padded with PKCS7 and prepended
+// with empty space of the AES block size (16 bytes) for the IV.
+func padPKCS7WithIV(src []byte) []byte {
+	missing := aes.BlockSize - (len(src) % aes.BlockSize)
+	newSize := len(src) + aes.BlockSize + missing
+	dest := make([]byte, newSize, newSize)
+	copy(dest[aes.BlockSize:], src)
+
+	padding := byte(missing)
+	for i := newSize - missing; i < newSize; i++ {
+		dest[i] = padding
+	}
+	return dest
+}
+
+func unpadPKCS7(src []byte) []byte {
+	padLen := src[len(src)-1]
+	return src[:len(src)-int(padLen)]
+}
diff --git a/vendor/github.com/Philipp15b/go-steam/cryptoutil/rsa.go b/vendor/github.com/Philipp15b/go-steam/cryptoutil/rsa.go
new file mode 100644
index 00000000..78cd954a
--- /dev/null
+++ b/vendor/github.com/Philipp15b/go-steam/cryptoutil/rsa.go
@@ -0,0 +1,31 @@
+package cryptoutil
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha1"
+	"crypto/x509"
+	"errors"
+)
+
+// Parses a DER encoded RSA public key
+func ParseASN1RSAPublicKey(derBytes []byte) (*rsa.PublicKey, error) {
+	key, err := x509.ParsePKIXPublicKey(derBytes)
+	if err != nil {
+		return nil, err
+	}
+	pubKey, ok := key.(*rsa.PublicKey)
+	if !ok {
+		return nil, errors.New("not an RSA public key")
+	}
+	return pubKey, nil
+}
+
+// Encrypts a message with the given public key using RSA-OAEP and the sha1 hash function.
+func RSAEncrypt(pub *rsa.PublicKey, msg []byte) []byte {
+	b, err := rsa.EncryptOAEP(sha1.New(), rand.Reader, pub, msg, nil)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}