3 files changed, 43 insertions, 15 deletions
diff --git a/internal/nametransform/longnames.go b/internal/nametransform/longnames.go
index e442b64..dad269b 100644
--- a/internal/nametransform/longnames.go
+++ b/internal/nametransform/longnames.go
@@ -1,12 +1,12 @@
 package nametransform
 
 import (
-	"syscall"
-	"path/filepath"
-	"io/ioutil"
 	"crypto/sha256"
 	"encoding/base64"
+	"io/ioutil"
+	"path/filepath"
 	"strings"
+	"syscall"
 
 	"github.com/rfjakob/gocryptfs/internal/toggledlog"
 )
@@ -39,28 +39,47 @@ func IsLongName(cName string) int {
 	return 1
 }
 
-// ReadLongName - read "path".name
+// ReadLongName - read path.name
 func ReadLongName(path string) (string, error) {
-	content, err := ioutil.ReadFile(path+longNameSuffix)
+	content, err := ioutil.ReadFile(path + longNameSuffix)
 	if err != nil {
 		toggledlog.Warn.Printf("ReadLongName: %v", err)
 	}
 	return string(content), err
 }
 
-// WriteLongName -
-func (n *NameTransform) WriteLongName(cDir string, hashedName string, plainName string) (err error) {
-	if len(plainName) > syscall.NAME_MAX {
-		return syscall.ENAMETOOLONG
+// DeleteLongName - if cPath ends in "gocryptfs.longname.[sha256]",
+// delete the "gocryptfs.longname.[sha256].name" file
+func DeleteLongName(cPath string) error {
+	if IsLongName(filepath.Base(cPath)) == 1 {
+		err := syscall.Unlink(cPath + longNameSuffix)
+		if err != nil {
+			toggledlog.Warn.Printf("DeleteLongName: %v", err)
+		}
+		return err
 	}
+	return nil
+}
 
+// WriteLongName - if cPath ends in "gocryptfs.longname.[sha256]", write the
+// "gocryptfs.longname.[sha256].name" file
+func (n *NameTransform) WriteLongName(cPath string, plainPath string) (err error) {
+	cHashedName := filepath.Base(cPath)
+	if IsLongName(cHashedName) != 1 {
+		// This is not a hashed file name, nothing to do
+		return nil
+	}
+	// Encrypt (but do not hash) the plaintext name
+	cDir := filepath.Dir(cPath)
 	dirIV, err := ReadDirIV(cDir)
 	if err != nil {
 		toggledlog.Warn.Printf("WriteLongName: %v", err)
 		return err
 	}
+	plainName := filepath.Base(plainPath)
 	cName := n.EncryptName(plainName, dirIV)
-	err = ioutil.WriteFile(filepath.Join(cDir, hashedName + longNameSuffix), []byte(cName), 0600)
+	// Write the encrypted name into gocryptfs.longname.[sha256].name
+	err = ioutil.WriteFile(filepath.Join(cDir, cHashedName+longNameSuffix), []byte(cName), 0600)
 	if err != nil {
 		toggledlog.Warn.Printf("WriteLongName: %v", err)
 	}
diff --git a/internal/nametransform/name_api.go b/internal/nametransform/name_api.go
index 391a5ce..7ac7d26 100644
--- a/internal/nametransform/name_api.go
+++ b/internal/nametransform/name_api.go
@@ -12,7 +12,7 @@ type NameTransform struct {
 func New(c *cryptocore.CryptoCore, useEME bool, longNames bool) *NameTransform {
 	return &NameTransform{
 		cryptoCore: c,
-		longNames: longNames,
+		longNames:  longNames,
 		useEME:     useEME,
 	}
 }
diff --git a/internal/nametransform/names_diriv.go b/internal/nametransform/names_diriv.go
index d45f91b..9336f5d 100644
--- a/internal/nametransform/names_diriv.go
+++ b/internal/nametransform/names_diriv.go
@@ -1,12 +1,12 @@
 package nametransform
 
 import (
-	"syscall"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
+	"syscall"
 
 	"github.com/rfjakob/gocryptfs/internal/cryptocore"
 	"github.com/rfjakob/gocryptfs/internal/toggledlog"
@@ -54,17 +54,23 @@ func WriteDirIV(dir string) error {
 	return ioutil.WriteFile(file, iv, 0444)
 }
 
-// EncryptPathDirIV - encrypt path using EME with DirIV
+// EncryptPathDirIV - encrypt relative plaintext path using EME with DirIV.
+// Components that are longer than 255 bytes are hashed.
 func (be *NameTransform) EncryptPathDirIV(plainPath string, rootDir string) (cipherPath string, err error) {
 	// Empty string means root directory
 	if plainPath == "" {
 		return plainPath, nil
 	}
+	// Reject names longer than 255 bytes already here. This relieves everybody
+	// who uses hashed long names from checking for that later.
+	baseName := filepath.Base(plainPath)
+	if len(baseName) > syscall.NAME_MAX {
+		return "", syscall.ENAMETOOLONG
+	}
 	// Check if the DirIV is cached
 	parentDir := filepath.Dir(plainPath)
 	found, iv, cParentDir := be.DirIVCache.lookup(parentDir)
 	if found {
-		baseName := filepath.Base(plainPath)
 		cBaseName := be.EncryptName(baseName, iv)
 		if be.longNames && len(cBaseName) > syscall.NAME_MAX {
 			cBaseName = HashLongName(cBaseName)
@@ -72,7 +78,7 @@ func (be *NameTransform) EncryptPathDirIV(plainPath string, rootDir string) (cip
 		cipherPath = cParentDir + "/" + cBaseName
 		return cipherPath, nil
 	}
-	// Walk the directory tree
+	// Not cached - walk the directory tree
 	var wd = rootDir
 	var encryptedNames []string
 	plainNames := strings.Split(plainPath, "/")
@@ -96,6 +102,9 @@ func (be *NameTransform) EncryptPathDirIV(plainPath string, rootDir string) (cip
 }
 
 // DecryptPathDirIV - decrypt path using EME with DirIV
+//
+// TODO This has only a single user, Readlink(), and only for compatability with
+// gocryptfs v0.5. Drop?
 func (be *NameTransform) DecryptPathDirIV(encryptedPath string, rootDir string) (string, error) {
 	var wd = rootDir
 	var plainNames []string