From c6dacd6f913b4c6eb7a8917af49190dce32db108 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Tue, 8 Dec 2015 16:13:29 +0100
Subject: Add EME filename encryption & enable it by default

---
 cryptfs/cryptfs_names.go | 156 -----------------------------------------------
 1 file changed, 156 deletions(-)
 delete mode 100644 cryptfs/cryptfs_names.go

(limited to 'cryptfs/cryptfs_names.go')

diff --git a/cryptfs/cryptfs_names.go b/cryptfs/cryptfs_names.go
deleted file mode 100644
index 8f8486b..0000000
--- a/cryptfs/cryptfs_names.go
+++ /dev/null
@@ -1,156 +0,0 @@
-package cryptfs
-
-// Filename encryption / decryption function
-
-import (
-	"crypto/aes"
-	"crypto/cipher"
-	"encoding/base64"
-	"errors"
-	"fmt"
-	"strings"
-)
-
-const (
-	OpEncrypt = iota
-	OpDecrypt
-)
-
-// DecryptName - decrypt base64-encoded encrypted filename "cipherName"
-func (be *CryptFS) DecryptName(cipherName string, iv []byte) (string, error) {
-
-	// Make sure relative symlinks still work after encryption
-	// by passing these through unchanged
-	if cipherName == "." || cipherName == ".." {
-		return cipherName, nil
-	}
-
-	bin, err := base64.URLEncoding.DecodeString(cipherName)
-	if err != nil {
-		return "", err
-	}
-
-	if len(bin)%aes.BlockSize != 0 {
-		return "", fmt.Errorf("Decoded length %d is not a multiple of the AES block size", len(bin))
-	}
-
-	cbc := cipher.NewCBCDecrypter(be.blockCipher, iv)
-	cbc.CryptBlocks(bin, bin)
-
-	bin, err = be.unPad16(bin)
-	if err != nil {
-		return "", err
-	}
-
-	plain := string(bin)
-	return plain, err
-}
-
-// EncryptName - encrypt filename
-func (be *CryptFS) encryptName(plainName string, iv []byte) string {
-
-	// Make sure relative symlinks still work after encryption
-	// by passing these trough unchanged
-	if plainName == "." || plainName == ".." {
-		return plainName
-	}
-
-	bin := []byte(plainName)
-	bin = be.pad16(bin)
-
-	cbc := cipher.NewCBCEncrypter(be.blockCipher, iv)
-	cbc.CryptBlocks(bin, bin)
-
-	cipherName64 := base64.URLEncoding.EncodeToString(bin)
-	return cipherName64
-}
-
-// TranslatePathZeroIV - encrypt or decrypt path using CBC with a constant all-zero IV.
-// Just splits the string on "/" and hands the parts to encryptName() / decryptName()
-func (be *CryptFS) TranslatePathZeroIV(path string, op int) (string, error) {
-	var err error
-
-	// Empty string means root directory
-	if path == "" {
-		return path, err
-	}
-
-	zeroIV := make([]byte, DIRIV_LEN)
-
-	// Run operation on each path component
-	var translatedParts []string
-	parts := strings.Split(path, "/")
-	for _, part := range parts {
-		if part == "" {
-			// This happens on "/foo/bar/" on the front and on the end.
-			// Don't panic.
-			translatedParts = append(translatedParts, "")
-			continue
-		}
-		var newPart string
-		if op == OpEncrypt {
-			newPart = be.encryptName(part, zeroIV)
-		} else {
-			newPart, err = be.DecryptName(part, zeroIV)
-			if err != nil {
-				return "", err
-			}
-		}
-		translatedParts = append(translatedParts, newPart)
-	}
-
-	return strings.Join(translatedParts, "/"), err
-}
-
-// pad16 - pad filename to 16 byte blocks using standard PKCS#7 padding
-// https://tools.ietf.org/html/rfc5652#section-6.3
-func (be *CryptFS) pad16(orig []byte) (padded []byte) {
-	oldLen := len(orig)
-	if oldLen == 0 {
-		panic("Padding zero-length string makes no sense")
-	}
-	padLen := aes.BlockSize - oldLen%aes.BlockSize
-	if padLen == 0 {
-		padLen = aes.BlockSize
-	}
-	newLen := oldLen + padLen
-	padded = make([]byte, newLen)
-	copy(padded, orig)
-	padByte := byte(padLen)
-	for i := oldLen; i < newLen; i++ {
-		padded[i] = padByte
-	}
-	return padded
-}
-
-// unPad16 - remove padding
-func (be *CryptFS) unPad16(orig []byte) ([]byte, error) {
-	oldLen := len(orig)
-	if oldLen%aes.BlockSize != 0 {
-		return nil, errors.New("Unaligned size")
-	}
-	// The last byte is always a padding byte
-	padByte := orig[oldLen-1]
-	// The padding byte's value is the padding length
-	padLen := int(padByte)
-	// Padding must be at least 1 byte
-	if padLen <= 0 {
-		return nil, errors.New("Padding cannot be zero-length")
-	}
-	// Larger paddings make no sense
-	if padLen > aes.BlockSize {
-		return nil, errors.New("Padding cannot be larger than 16")
-	}
-	// All padding bytes must be identical
-	for i := oldLen - padLen; i < oldLen; i++ {
-		if orig[i] != padByte {
-			return nil, errors.New(fmt.Sprintf("Padding byte at i=%d is invalid", i))
-		}
-	}
-	newLen := oldLen - padLen
-	// Padding an empty string makes no sense
-	if newLen == 0 {
-		return nil, errors.New("Unpadded length is zero")
-	}
-	return orig[0:newLen], nil
-}
-- 
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