nametransform: fix Raw64 not affecting symlink targets

The symlink functions incorrectly hardcoded the padded
base64 variant.

internal/fusefrontend/fs.go

@@ -4,7 +4,6 @@ package fusefrontend
 // FUSE operations on paths
 
 import (
-	"encoding/base64"
 	"os"
 	"path/filepath"
 	"sync"
@@ -298,7 +297,7 @@ func (fs *FS) Readlink(path string, context *fuse.Context) (out string, status f
 		return cTarget, fuse.OK
 	}
 	// Symlinks are encrypted like file contents (GCM) and base64-encoded
-	cBinTarget, err := base64.URLEncoding.DecodeString(cTarget)
+	cBinTarget, err := fs.nameTransform.B64.DecodeString(cTarget)
 	if err != nil {
 		tlog.Warn.Printf("Readlink: %v", err)
 		return "", fuse.EIO
@@ -362,7 +361,7 @@ func (fs *FS) Symlink(target string, linkName string, context *fuse.Context) (co
 	}
 	// Symlinks are encrypted like file contents (GCM) and base64-encoded
 	cBinTarget := fs.contentEnc.EncryptBlock([]byte(target), 0, nil)
-	cTarget := base64.URLEncoding.EncodeToString(cBinTarget)
+	cTarget := fs.nameTransform.B64.EncodeToString(cBinTarget)
 	// Handle long file name
 	cName := filepath.Base(cPath)
 	if nametransform.IsLongContent(cName) {

internal/fusefrontend_reverse/rfs.go

@@ -1,7 +1,6 @@
 package fusefrontend_reverse
 
 import (
-	"encoding/base64"
 	"fmt"
 	"log"
 	"os"
@@ -355,6 +354,6 @@ func (rfs *ReverseFS) Readlink(cipherPath string, context *fuse.Context) (string
 	nonce := derivePathIV(cipherPath, ivPurposeSymlinkIV)
 	// Symlinks are encrypted like file contents and base64-encoded
 	cBinTarget := rfs.contentEnc.EncryptBlockNonce([]byte(plainTarget), 0, nil, nonce)
-	cTarget := base64.URLEncoding.EncodeToString(cBinTarget)
+	cTarget := rfs.nameTransform.B64.EncodeToString(cBinTarget)
 	return cTarget, fuse.OK
 }

internal/nametransform/longnames.go

@@ -25,7 +25,7 @@ const (
 // "gocryptfs.longname.[sha256]"
 func (n *NameTransform) HashLongName(name string) string {
 	hashBin := sha256.Sum256([]byte(name))
-	hashBase64 := n.b64.EncodeToString(hashBin[:])
+	hashBase64 := n.B64.EncodeToString(hashBin[:])
 	return longNamePrefix + hashBase64
 }
 

internal/nametransform/names.go

@@ -16,8 +16,9 @@ type NameTransform struct {
 	emeCipher  *eme.EMECipher
 	longNames  bool
 	DirIVCache dirIVCache
-	// b64 = either base64.URLEncoding or base64.RawURLEncoding
-	b64 *base64.Encoding
+	// B64 = either base64.URLEncoding or base64.RawURLEncoding, depeding
+	// on the Raw64 feature flag
+	B64 *base64.Encoding
 }
 
 // New returns a new NameTransform instance.
@@ -29,7 +30,7 @@ func New(e *eme.EMECipher, longNames bool, raw64 bool) *NameTransform {
 	return &NameTransform{
 		emeCipher: e,
 		longNames: longNames,
-		b64:       b64,
+		B64:       b64,
 	}
 }
 
@@ -38,7 +39,7 @@ func New(e *eme.EMECipher, longNames bool, raw64 bool) *NameTransform {
 // This function is exported because it allows for a very efficient readdir
 // implementation (read IV once, decrypt all names using this function).
 func (n *NameTransform) DecryptName(cipherName string, iv []byte) (string, error) {
-	bin, err := n.b64.DecodeString(cipherName)
+	bin, err := n.B64.DecodeString(cipherName)
 	if err != nil {
 		return "", err
 	}
@@ -69,6 +70,6 @@ func (n *NameTransform) EncryptName(plainName string, iv []byte) (cipherName64 s
 	bin := []byte(plainName)
 	bin = pad16(bin)
 	bin = n.emeCipher.Encrypt(iv, bin)
-	cipherName64 = n.b64.EncodeToString(bin)
+	cipherName64 = n.B64.EncodeToString(bin)
 	return cipherName64
 }