Drop deprecated "-emenames" option

The EMENames feature flag is already mandatory, dropping the command
line option is the final step.

Documentation/MANPAGE.md

@@ -46,11 +46,6 @@ user_allow_other is set in /etc/fuse.conf. This option is equivalent to
 **-d, -debug**
 :	Enable debug output
 
-**-emenames**
-:	Use EME filename encryption (default true), implies diriv.
-This flag is useful when recovering old gocryptfs filesystems using
-"-masterkey". It is ignored (stays at the default) otherwise.
-
 **-extpass string**
 :	Use an external program (like ssh-askpass) for the password prompt.
 The program should return the password on stdout, a trailing newline is

internal/fusefrontend/args.go

@@ -6,7 +6,6 @@ type Args struct {
 	Cipherdir      string
 	OpenSSL        bool
 	PlaintextNames bool
-	EMENames       bool
 	GCMIV128       bool
 	LongNames      bool
 }

internal/fusefrontend/fs.go

@@ -38,7 +38,7 @@ func NewFS(args Args) *FS {
 
 	cryptoCore := cryptocore.New(args.Masterkey, args.OpenSSL, args.GCMIV128)
 	contentEnc := contentenc.New(cryptoCore, contentenc.DefaultBS)
-	nameTransform := nametransform.New(cryptoCore, args.EMENames, args.LongNames)
+	nameTransform := nametransform.New(cryptoCore, args.LongNames)
 
 	return &FS{
 		FileSystem:    pathfs.NewLoopbackFileSystem(args.Cipherdir),

internal/nametransform/names.go

@@ -4,7 +4,6 @@ package nametransform
 
 import (
 	"crypto/aes"
-	"crypto/cipher"
 	"encoding/base64"
 	"fmt"
 
@@ -15,16 +14,14 @@ import (
 
 type NameTransform struct {
 	cryptoCore *cryptocore.CryptoCore
-	useEME     bool
 	longNames  bool
 	DirIVCache dirIVCache
 }
 
-func New(c *cryptocore.CryptoCore, useEME bool, longNames bool) *NameTransform {
+func New(c *cryptocore.CryptoCore, longNames bool) *NameTransform {
 	return &NameTransform{
 		cryptoCore: c,
 		longNames:  longNames,
-		useEME:     useEME,
 	}
 }
 
@@ -35,28 +32,18 @@ func New(c *cryptocore.CryptoCore, useEME bool, longNames 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 := 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))
 	}
-
-	if n.useEME {
-		bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionDecrypt)
-	} else {
-		cbc := cipher.NewCBCDecrypter(n.cryptoCore.BlockCipher, iv)
-		cbc.CryptBlocks(bin, bin)
-	}
-
+	bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionDecrypt)
 	bin, err = unPad16(bin)
 	if err != nil {
 		return "", err
 	}
-
 	plain := string(bin)
 	return plain, err
 }
@@ -68,17 +55,9 @@ func (n *NameTransform) DecryptName(cipherName string, iv []byte) (string, error
 // This function is exported because fusefrontend needs access to the full (not hashed)
 // name if longname is used. Otherwise you should use EncryptPathDirIV()
 func (n *NameTransform) EncryptName(plainName string, iv []byte) (cipherName64 string) {
-
 	bin := []byte(plainName)
 	bin = pad16(bin)
-
-	if n.useEME {
-		bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionEncrypt)
-	} else {
-		cbc := cipher.NewCBCEncrypter(n.cryptoCore.BlockCipher, iv)
-		cbc.CryptBlocks(bin, bin)
-	}
-
+	bin = eme.Transform(n.cryptoCore.BlockCipher, iv, bin, eme.DirectionEncrypt)
 	cipherName64 = base64.URLEncoding.EncodeToString(bin)
 	return cipherName64
 }

main.go

@@ -42,7 +42,7 @@ const (
 
 type argContainer struct {
 	debug, init, zerokey, fusedebug, openssl, passwd, foreground, version,
-	plaintextnames, quiet, emenames, gcmiv128, nosyslog, wpanic,
+	plaintextnames, quiet, gcmiv128, nosyslog, wpanic,
 	longnames, allow_other, ro bool
 	masterkey, mountpoint, cipherdir, cpuprofile, config, extpass,
 	memprofile string
@@ -174,7 +174,6 @@ func main() {
 	flagSet.BoolVar(&args.plaintextnames, "plaintextnames", false, "Do not encrypt file names")
 	flagSet.BoolVar(&args.quiet, "q", false, "")
 	flagSet.BoolVar(&args.quiet, "quiet", false, "Quiet - silence informational messages")
-	flagSet.BoolVar(&args.emenames, "emenames", true, "Use EME filename encryption. This option implies diriv.")
 	flagSet.BoolVar(&args.gcmiv128, "gcmiv128", true, "Use an 128-bit IV for GCM encryption instead of Go's default of 96 bits")
 	flagSet.BoolVar(&args.nosyslog, "nosyslog", false, "Do not redirect output to syslog when running in the background")
 	flagSet.BoolVar(&args.wpanic, "wpanic", false, "When encountering a warning, panic and exit immediately")
@@ -369,21 +368,15 @@ func initFuseFrontend(key []byte, args argContainer, confFile *configfile.ConfFi
 		Masterkey:      key,
 		OpenSSL:        args.openssl,
 		PlaintextNames: args.plaintextnames,
-		EMENames:       args.emenames,
 		GCMIV128:       args.gcmiv128,
 		LongNames:      args.longnames,
 	}
 	// confFile is nil when "-zerokey" or "-masterkey" was used
 	if confFile != nil {
 		// Settings from the config file override command line args
 		frontendArgs.PlaintextNames = confFile.IsFeatureFlagSet(configfile.FlagPlaintextNames)
-		frontendArgs.EMENames = confFile.IsFeatureFlagSet(configfile.FlagEMENames)
 		frontendArgs.GCMIV128 = confFile.IsFeatureFlagSet(configfile.FlagGCMIV128)
 	}
-	// PlainTexnames disables EMENames
-	if frontendArgs.PlaintextNames {
-		frontendArgs.EMENames = false
-	}
 	jsonBytes, _ := json.MarshalIndent(frontendArgs, "", "\t")
 	tlog.Debug.Printf("frontendArgs: %s", string(jsonBytes))
 

tests/example_filesystems/example_filesystems_test.go

@@ -104,24 +104,12 @@ func TestExampleFSv04(t *testing.T) {
 // Test example_filesystems/v0.5
 // with password mount and -masterkey mount
 func TestExampleFSv05(t *testing.T) {
-	pDir := test_helpers.TmpDir + "TestExampleFsV05/"
 	cDir := "v0.5"
-	err := os.Mkdir(pDir, 0777)
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = test_helpers.Mount(cDir, pDir, false, "-extpass", "echo test")
+	pDir := test_helpers.TmpDir + cDir
+	err := test_helpers.Mount(cDir, pDir, false, "-extpass", "echo test")
 	if err == nil {
 		t.Errorf("Mounting deprecated FS should fail")
 	}
-	test_helpers.MountOrFatal(t, cDir, pDir, "-masterkey", "199eae55-36bff4af-83b9a3a2-4fa16f65-"+
-		"1549ccdb-2d08d1f0-b1b26965-1b61f896", "-emenames=false", "-gcmiv128=false")
-	checkExampleFS(t, pDir, true)
-	test_helpers.Unmount(pDir)
-	err = os.Remove(pDir)
-	if err != nil {
-		t.Error(err)
-	}
 }
 
 // Test example_filesystems/v0.6