Opening plaintext names volumes

app/build.gradle

@@ -15,8 +15,8 @@ android {
         applicationId "sushi.hardcore.droidfs"
         minSdkVersion 21
         targetSdkVersion 29
-        versionCode 9
+        versionCode 10
-        versionName "1.4.1"
+        versionName "1.4.2"
 
         ndk {
             abiFilters 'x86_64', 'armeabi-v7a', 'arm64-v8a'
@@ -56,11 +56,11 @@ dependencies {
     implementation "com.github.bumptech.glide:glide:4.11.0"
     implementation "com.google.android.exoplayer:exoplayer-core:2.11.7"
     implementation "com.google.android.exoplayer:exoplayer-ui:2.11.7"
-    implementation "androidx.biometric:biometric:1.0.1"
+    implementation "androidx.biometric:biometric:1.1.0"
 
-    def camerax_version = "1.0.0-rc01"
+    def camerax_version = "1.1.0-alpha01"
     implementation "androidx.camera:camera-camera2:$camerax_version"
     implementation "androidx.camera:camera-lifecycle:$camerax_version"
-    implementation "androidx.camera:camera-view:1.0.0-alpha20"
+    implementation "androidx.camera:camera-view:1.0.0-alpha21"
-    implementation "androidx.camera:camera-extensions:1.0.0-alpha20"
+    implementation "androidx.camera:camera-extensions:1.0.0-alpha21"
 }

app/libgocryptfs/main.go

@@ -2,25 +2,25 @@ package main
 
 import (
 	"C"
-  "crypto/cipher"
-  "crypto/aes"
-  "syscall"
-  "strings"
 	"bytes"
-  "unsafe"
+	"crypto/aes"
-  "os"
+	"crypto/cipher"
-  "io"
 	"fmt"
-  "path/filepath"
 	"golang.org/x/sys/unix"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"unsafe"
 
 	"./gocryptfs_internal/cryptocore"
-  "./gocryptfs_internal/stupidgcm"
 	"./gocryptfs_internal/eme"
 	"./gocryptfs_internal/nametransform"
-  "./rewrites/syscallcompat"
+	"./gocryptfs_internal/stupidgcm"
 	"./rewrites/configfile"
 	"./rewrites/contentenc"
+	"./rewrites/syscallcompat"
 )
 
 const (
@@ -40,6 +40,7 @@ type File struct {
 
 type SessionVars struct {
 	root_cipher_dir string
+	plainTextNames  bool
 	nameTransform   *nametransform.NameTransform
 	cryptoCore      *cryptocore.CryptoCore
 	contentEnc      *contentenc.ContentEnc
@@ -72,6 +73,16 @@ func clear_dirCache(sessionID int) {
 
 func openBackingDir(sessionID int, relPath string) (dirfd int, cName string, err error) {
 	dirRelPath := nametransform.Dir(relPath)
+	// With PlaintextNames, we don't need to read DirIVs. Easy.
+	if sessions[sessionID].plainTextNames {
+		dirfd, err = syscallcompat.OpenDirNofollow(sessions[sessionID].root_cipher_dir, dirRelPath)
+		if err != nil {
+			return -1, "", err
+		}
+		// If relPath is empty, cName is ".".
+		cName = filepath.Base(relPath)
+		return dirfd, cName, nil
+	}
 	dir, ok := sessions[sessionID].dirCache[dirRelPath]
 	if ok {
 		// If relPath is empty, cName is ".".
@@ -487,6 +498,9 @@ func init_new_session(root_cipher_dir string, masterkey []byte, cf *configfile.C
 	}
 	if err == nil {
 		var new_session SessionVars
+
+		new_session.plainTextNames = cf.IsFeatureFlagSet(configfile.FlagPlaintextNames)
+
 		emeCipher = eme.New(emeBlockCipher)
 		new_session.nameTransform = nametransform.New(emeCipher, true, true)
 
@@ -524,7 +538,7 @@ func init_new_session(root_cipher_dir string, masterkey []byte, cf *configfile.C
 		if sessions == nil {
 			sessions = make(map[int]SessionVars)
 		}
-    sessions[sessionID] = new_session;
+		sessions[sessionID] = new_session
 		return sessionID
 	}
 	return -1
@@ -614,11 +628,13 @@ func gcf_list_dir(sessionID int, dirName string) (*C.char, *C.int, C.int) {
 	}
 	// Get DirIV (stays nil if PlaintextNames is used)
 	var cachedIV []byte
+	if !sessions[sessionID].plainTextNames {
 		// Read the DirIV from disk
 		cachedIV, err = nametransform.ReadDirIVAt(fd)
 		if err != nil {
 			return nil, nil, 0
 		}
+	}
 	// Decrypted directory entries
 	var plain strings.Builder
 	var modes []uint32
@@ -629,6 +645,11 @@ func gcf_list_dir(sessionID int, dirName string) (*C.char, *C.int, C.int) {
 			// silently ignore "gocryptfs.conf" in the top level dir
 			continue
 		}
+		if sessions[sessionID].plainTextNames {
+			plain.WriteString(cipherEntries[i].Name + "\x00")
+			modes = append(modes, cipherEntries[i].Mode)
+			continue
+		}
 		if cName == nametransform.DirIVFilename {
 			// silently ignore "gocryptfs.diriv" everywhere if dirIV is enabled
 			continue
@@ -670,6 +691,18 @@ func gcf_mkdir(sessionID int, newPath string) bool {
 		return false
 	}
 	defer syscall.Close(dirfd)
+
+	if sessions[sessionID].plainTextNames {
+		err = syscallcompat.Mkdirat(dirfd, cName, folder_mode)
+		if err != nil {
+			return false
+		}
+		var ust unix.Stat_t
+		err = syscallcompat.Fstatat(dirfd, cName, &ust, unix.AT_SYMLINK_NOFOLLOW)
+		if err != nil {
+			return false
+		}
+	} else {
 		// We need write and execute permissions to create gocryptfs.diriv.
 		// Also, we need read permissions to open the directory (to avoid
 		// race-conditions between getting and setting the mode).
@@ -718,6 +751,7 @@ func gcf_mkdir(sessionID int, newPath string) bool {
 				return false
 			}
 		}
+	}
 	return true
 }
 
@@ -729,6 +763,11 @@ func gcf_rmdir(sessionID int, relPath string) bool {
 		return false
 	}
 	defer syscall.Close(parentDirFd)
+	if sessions[sessionID].plainTextNames {
+		// Unlinkat with AT_REMOVEDIR is equivalent to Rmdir
+		err = unix.Unlinkat(parentDirFd, cName, unix.AT_REMOVEDIR)
+		return err_to_bool(err)
+	}
 	dirfd, err := syscallcompat.Openat(parentDirFd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NOFOLLOW, 0)
 	if err != nil {
 		return false
@@ -797,7 +836,7 @@ func gcf_open_write_mode(sessionID int, path string) int {
 	defer syscall.Close(dirfd)
 	fd := -1
 	// Handle long file name
-	if nametransform.IsLongContent(cName) {
+	if !sessions[sessionID].plainTextNames && nametransform.IsLongContent(cName) {
 		// Create ".name"
 		err = sessions[sessionID].nameTransform.WriteLongNameAt(dirfd, cName, path)
 		if err != nil {
@@ -851,7 +890,7 @@ func gcf_close_file(sessionID, handleID int){
 func gcf_read_file(sessionID, handleID int, offset uint64, dst_buff []byte) uint32 {
 	length := uint64(len(dst_buff))
 	if length > contentenc.MAX_KERNEL_WRITE {
-    return 0;
+		return 0
 	}
 
 	out, _ := doRead(sessionID, handleID, dst_buff[:0], offset, length)
@@ -863,7 +902,7 @@ func gcf_read_file(sessionID, handleID int, offset uint64, dst_buff []byte) uint
 func gcf_write_file(sessionID, handleID int, offset uint64, data []byte) uint32 {
 	length := uint64(len(data))
 	if length > contentenc.MAX_KERNEL_WRITE {
-    return 0;
+		return 0
 	}
 
 	written, _ := doWrite(sessionID, handleID, data, offset)
@@ -899,6 +938,11 @@ func gcf_rename(sessionID int, oldPath string, newPath string) bool {
 		return false
 	}
 	defer syscall.Close(newDirfd)
+
+	// Easy case.
+	if sessions[sessionID].plainTextNames {
+		return err_to_bool(syscallcompat.Renameat(oldDirfd, oldCName, newDirfd, newCName))
+	}
 	// Long destination file name: create .name file
 	nameFileAlreadyThere := false
 	if nametransform.IsLongContent(newCName) {
@@ -950,7 +994,7 @@ func gcf_remove_file(sessionID int, path string) bool {
 		return false
 	}
 	// Delete ".name" file
-	if nametransform.IsLongContent(cName) {
+	if !sessions[sessionID].plainTextNames && nametransform.IsLongContent(cName) {
 		err = nametransform.DeleteLongNameAt(dirfd, cName)
 	}
 	return err_to_bool(err)