hardcoresushi
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libgocryptfs
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Add pathfs frontend (uses go-fuse instead of bazil-fuse), part I 

Currently fails main_test.go, will be fixed in part II
This commit is contained in:
Jakob Unterwurzacher 2015-09-08 00:54:24 +02:00
parent b65882985d
commit 889ae90081
7 changed files with 509 additions and 19 deletions
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7
.gitignore vendored
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@ -1,2 +1,9 @@
# Binary
/gocryptfs
# Manual test mounts
/cipherdir
/mountpoint
# main_test.go temporary files
/main_test_tmp

39
cryptfs/cryptfs_content.go
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@ -77,7 +77,7 @@ func (be *CryptFS) EncryptBlock(plaintext []byte) []byte {
return ciphertext
}
// Split a plaintext byte range into (possible partial) blocks
// Split a plaintext byte range into (possibly partial) blocks
func (be *CryptFS) SplitRange(offset uint64, length uint64) []intraBlock {
var b intraBlock
var parts []intraBlock
@ -113,6 +113,22 @@ func (be *CryptFS) minu64(x uint64, y uint64) uint64 {
return y
}
// CiphertextRange - Get byte range in backing ciphertext corresponding
// to plaintext range. Returns a range aligned to ciphertext blocks.
func (be *CryptFS) CiphertextRange(offset uint64, length uint64) (uint64, uint64, int) {
// Decrypting the ciphertext will yield too many plaintext bytes. Skip this number
// of bytes from the front.
skip := offset % be.plainBS
firstBlockNo := offset / be.plainBS
lastBlockNo := ( offset + length - 1 ) / be.plainBS
alignedOffset := firstBlockNo * be.cipherBS
alignedLength := (lastBlockNo - firstBlockNo + 1) * be.cipherBS
return alignedOffset, alignedLength, int(skip)
}
// Get the byte range in the ciphertext corresponding to blocks
// (full blocks!)
func (be *CryptFS) JoinCiphertextRange(blocks []intraBlock) (uint64, uint64) {
@ -138,3 +154,24 @@ func (be *CryptFS) CropPlaintext(plaintext []byte, blocks []intraBlock) []byte {
}
return cropped
}
// MergeBlocks - Merge newData into oldData at offset
// New block may be bigger than both newData and oldData
func (be *CryptFS) MergeBlocks(oldData []byte, newData []byte, offset int) []byte {
// Make block of maximum size
out := make([]byte, be.plainBS)
// Copy old and new data into it
copy(out, oldData)
l := len(newData)
copy(out[offset:offset + l], newData)
// Crop to length
outLen := len(oldData)
newLen := offset + len(newData)
if outLen < newLen {
outLen = newLen
}
return out[0:outLen]
}

2
cryptfs/log.go
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@ -15,5 +15,5 @@ func (l logChannel) Printf(format string, args ...interface{}) {
}
var Debug = logChannel{false}
var Debug = logChannel{true}
var Warn = logChannel{true}

77
main.go
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@ -1,18 +1,29 @@
package main
import (
"bazil.org/fuse"
fusefs "bazil.org/fuse/fs"
"flag"
"fmt"
frontend "github.com/rfjakob/gocryptfs/cluefs_frontend"
"os"
"path/filepath"
"time"
"github.com/rfjakob/gocryptfs/cluefs_frontend"
"github.com/rfjakob/gocryptfs/pathfs_frontend"
bazilfuse "bazil.org/fuse"
bazilfusefs "bazil.org/fuse/fs"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/hanwen/go-fuse/fuse/pathfs"
)
const (
USE_CLUEFS = false
USE_OPENSSL = false
PATHFS_DEBUG = false
PROGRAM_NAME = "gocryptfs"
USE_OPENSSL = true
ERREXIT_USAGE = 1
ERREXIT_NEWFS = 2
@ -29,27 +40,34 @@ func main() {
fmt.Printf("usage: %s CIPHERDIR MOUNTPOINT\n", PROGRAM_NAME)
os.Exit(ERREXIT_USAGE)
}
cipherdir, _ := filepath.Abs(flag.Arg(0))
mountpoint, err := filepath.Abs(flag.Arg(1))
mountpoint, _ := filepath.Abs(flag.Arg(1))
// Create the file system object
var key [16]byte
cfs, err := frontend.NewFS(key, cipherdir, USE_OPENSSL)
if USE_CLUEFS {
cluefsFrontend(key, cipherdir, mountpoint)
} else {
pathfsFrontend(key, cipherdir, mountpoint)
}
}
func cluefsFrontend(key [16]byte, cipherdir string, mountpoint string) {
cfs, err := cluefs_frontend.NewFS(key, cipherdir, USE_OPENSSL)
if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_NEWFS)
}
// Mount the file system
mountOpts := []fuse.MountOption{
fuse.FSName(PROGRAM_NAME),
fuse.Subtype(PROGRAM_NAME),
fuse.VolumeName(PROGRAM_NAME),
fuse.LocalVolume(),
fuse.MaxReadahead(1024 * 1024),
mountOpts := []bazilfuse.MountOption{
bazilfuse.FSName(PROGRAM_NAME),
bazilfuse.Subtype(PROGRAM_NAME),
bazilfuse.VolumeName(PROGRAM_NAME),
bazilfuse.LocalVolume(),
bazilfuse.MaxReadahead(1024 * 1024),
}
conn, err := fuse.Mount(mountpoint, mountOpts...)
conn, err := bazilfuse.Mount(mountpoint, mountOpts...)
if err != nil {
fmt.Println(err)
os.Exit(ERREXIT_MOUNT)
@ -57,7 +75,7 @@ func main() {
defer conn.Close()
// Start serving requests
if err = fusefs.Serve(conn, cfs); err != nil {
if err = bazilfusefs.Serve(conn, cfs); err != nil {
fmt.Println(err)
os.Exit(ERREXIT_SERVE)
}
@ -72,3 +90,30 @@ func main() {
// We are done
os.Exit(0)
}
func pathfsFrontend(key [16]byte, cipherdir string, mountpoint string){
finalFs := pathfs_frontend.NewFS(key, cipherdir, USE_OPENSSL)
opts := &nodefs.Options{
// These options are to be compatible with libfuse defaults,
// making benchmarking easier.
NegativeTimeout: time.Second,
AttrTimeout: time.Second,
EntryTimeout: time.Second,
}
pathFs := pathfs.NewPathNodeFs(finalFs, nil)
conn := nodefs.NewFileSystemConnector(pathFs.Root(), opts)
mOpts := &fuse.MountOptions{
AllowOther: false,
}
state, err := fuse.NewServer(conn.RawFS(), mountpoint, mOpts)
if err != nil {
fmt.Printf("Mount fail: %v\n", err)
os.Exit(1)
}
state.SetDebug(PATHFS_DEBUG)
fmt.Println("Mounted!")
state.Serve()
}

2
main_test.go
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@ -12,7 +12,7 @@ import (
"time"
)
const tmpDir = "test_tmp_dir/"
const tmpDir = "main_test_tmp/"
const plainDir = tmpDir + "plain/"
const cipherDir = tmpDir + "cipher/"

235
pathfs_frontend/file.go Normal file
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@ -0,0 +1,235 @@
package pathfs_frontend
import (
"io"
"bytes"
"fmt"
"os"
"sync"
"syscall"
"time"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/rfjakob/gocryptfs/cryptfs"
)
// File - based on loopbackFile in go-fuse/fuse/nodefs/files.go
type file struct {
fd *os.File
// os.File is not threadsafe. Although fd themselves are
// constant during the lifetime of an open file, the OS may
// reuse the fd number after it is closed. When open races
// with another close, they may lead to confusion as which
// file gets written in the end.
lock sync.Mutex
// Was the file opened O_WRONLY?
writeOnly bool
// Parent CryptFS
cfs *cryptfs.CryptFS
}
func NewFile(fd *os.File, writeOnly bool, cfs *cryptfs.CryptFS) nodefs.File {
return &file{
fd: fd,
writeOnly: writeOnly,
cfs: cfs,
}
}
func (f *file) InnerFile() nodefs.File {
return nil
}
func (f *file) SetInode(n *nodefs.Inode) {
}
func (f *file) String() string {
return fmt.Sprintf("cryptFile(%s)", f.fd.Name())
}
// Read - FUSE call
func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fuse.Status) {
cryptfs.Debug.Printf("\n\nGot read request: len=%d off=%d\n", len(buf), off)
if f.writeOnly {
return nil, fuse.EBADF
}
// Read the backing ciphertext in one go
alignedOffset, alignedLength, skip := f.cfs.CiphertextRange(uint64(off), uint64(len(buf)))
ciphertext := make([]byte, int(alignedLength))
_, err := f.fd.ReadAt(ciphertext, int64(alignedOffset))
if err != nil && err != io.EOF {
cryptfs.Warn.Printf("Read error: %s\n", err.Error())
return nil, fuse.ToStatus(err)
}
// Decrypt it
plaintext, err := f.cfs.DecryptBlocks(ciphertext)
if err != nil {
cryptfs.Warn.Printf("Decryption error: %s\n", err.Error())
return nil, fuse.EIO
}
// Crop down to the relevant part
var out []byte
lenHave := len(plaintext)
lenWant := skip + len(buf)
if lenHave > lenWant {
out = plaintext[skip:skip + len(buf)]
} else if lenHave > skip {
out = plaintext[skip:lenHave]
}
// else: out stays empty
fmt.Printf("Read: returning %d bytes\n", len(plaintext))
return fuse.ReadResultData(out), fuse.OK
}
// Write - FUSE call
func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) {
var written uint32
var status fuse.Status
dataBuf := bytes.NewBuffer(data)
blocks := f.cfs.SplitRange(uint64(off), uint64(len(data)))
for _, b := range(blocks) {
blockData := dataBuf.Next(int(b.Length))
// Incomplete block -> Read-Modify-Write
if b.IsPartial() {
// Read
oldData := make([]byte, f.cfs.PlainBS())
o, _ := b.PlaintextRange()
res, status := f.Read(oldData, int64(o))
oldData, _ = res.Bytes(oldData)
if status != fuse.OK {
return written, status
}
// Modify
blockData = f.cfs.MergeBlocks(oldData, blockData, int(b.Offset))
}
// Write
blockOffset, _ := b.CiphertextRange()
blockData = f.cfs.EncryptBlock(blockData)
_, err := f.fd.WriteAt(blockData, int64(blockOffset))
if err != nil {
cryptfs.Warn.Printf("Write failed: %s\n", err.Error())
status = fuse.ToStatus(err)
break
}
written += uint32(b.Length)
}
return written, status
}
// Release - FUSE call, forget file
func (f *file) Release() {
f.lock.Lock()
f.fd.Close()
f.lock.Unlock()
}
// Flush - FUSE call
func (f *file) Flush() fuse.Status {
f.lock.Lock()
// Since Flush() may be called for each dup'd fd, we don't
// want to really close the file, we just want to flush. This
// is achieved by closing a dup'd fd.
newFd, err := syscall.Dup(int(f.fd.Fd()))
f.lock.Unlock()
if err != nil {
return fuse.ToStatus(err)
}
err = syscall.Close(newFd)
return fuse.ToStatus(err)
}
func (f *file) Fsync(flags int) (code fuse.Status) {
f.lock.Lock()
r := fuse.ToStatus(syscall.Fsync(int(f.fd.Fd())))
f.lock.Unlock()
return r
}
func (f *file) Truncate(size uint64) fuse.Status {
f.lock.Lock()
r := fuse.ToStatus(syscall.Ftruncate(int(f.fd.Fd()), int64(size)))
f.lock.Unlock()
return r
}
func (f *file) Chmod(mode uint32) fuse.Status {
f.lock.Lock()
r := fuse.ToStatus(f.fd.Chmod(os.FileMode(mode)))
f.lock.Unlock()
return r
}
func (f *file) Chown(uid uint32, gid uint32) fuse.Status {
f.lock.Lock()
r := fuse.ToStatus(f.fd.Chown(int(uid), int(gid)))
f.lock.Unlock()
return r
}
func (f *file) GetAttr(a *fuse.Attr) fuse.Status {
st := syscall.Stat_t{}
f.lock.Lock()
err := syscall.Fstat(int(f.fd.Fd()), &st)
f.lock.Unlock()
if err != nil {
return fuse.ToStatus(err)
}
a.FromStat(&st)
return fuse.OK
}
func (f *file) Allocate(off uint64, sz uint64, mode uint32) fuse.Status {
f.lock.Lock()
err := syscall.Fallocate(int(f.fd.Fd()), mode, int64(off), int64(sz))
f.lock.Unlock()
if err != nil {
return fuse.ToStatus(err)
}
return fuse.OK
}
const _UTIME_NOW = ((1 << 30) - 1)
const _UTIME_OMIT = ((1 << 30) - 2)
func (f *file) Utimens(a *time.Time, m *time.Time) fuse.Status {
tv := make([]syscall.Timeval, 2)
if a == nil {
tv[0].Usec = _UTIME_OMIT
} else {
n := a.UnixNano()
tv[0] = syscall.NsecToTimeval(n)
}
if m == nil {
tv[1].Usec = _UTIME_OMIT
} else {
n := a.UnixNano()
tv[1] = syscall.NsecToTimeval(n)
}
f.lock.Lock()
err := syscall.Futimes(int(f.fd.Fd()), tv)
f.lock.Unlock()
return fuse.ToStatus(err)
}

166
pathfs_frontend/fs.go Normal file
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@ -0,0 +1,166 @@
package pathfs_frontend
import (
"os"
"path/filepath"
"time"
"fmt"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/hanwen/go-fuse/fuse/pathfs"
"github.com/rfjakob/gocryptfs/cryptfs"
)
type FS struct {
*cryptfs.CryptFS
pathfs.FileSystem // loopbackFileSystem
backing string // Backing directory
}
// Encrypted FUSE overlay filesystem
func NewFS(key [16]byte, backing string, useOpenssl bool) *FS {
return &FS{
CryptFS: cryptfs.NewCryptFS(key, useOpenssl),
FileSystem: pathfs.NewLoopbackFileSystem(backing),
backing: backing,
}
}
// GetPath - get the absolute path of the backing file
func (fs *FS) GetPath(relPath string) string {
return filepath.Join(fs.backing, fs.EncryptPath(relPath))
}
func (fs *FS) GetAttr(name string, context *fuse.Context) (*fuse.Attr, fuse.Status) {
a, status := fs.FileSystem.GetAttr(fs.EncryptPath(name), context)
if a == nil {
return a, status
}
a.Size = fs.PlainSize(a.Size)
return a, status
}
func (fs *FS) OpenDir(name string, context *fuse.Context) ([]fuse.DirEntry, fuse.Status) {
cipherEntries, status := fs.FileSystem.OpenDir(fs.EncryptPath(name), context);
var plain []fuse.DirEntry
var skipped int
if cipherEntries != nil {
for i := range cipherEntries {
n, err := fs.DecryptPath(cipherEntries[i].Name)
if err != nil {
fmt.Printf("Skipping invalid filename \"%s\": %s\n", cipherEntries[i].Name, err)
skipped++
continue
}
cipherEntries[i].Name = n
plain = append(plain, cipherEntries[i])
}
}
return plain, status
}
// We always need read access to do read-modify-write cycles
func (fs *FS) mangleOpenFlags(flags uint32) (newFlags int, writeOnly bool) {
newFlags = int(flags)
if newFlags & os.O_WRONLY > 0 {
writeOnly = true
newFlags = newFlags ^ os.O_WRONLY | os.O_RDWR
}
// We also cannot open the file in append mode, we need to seek back for RMW
newFlags = newFlags &^ os.O_APPEND
return newFlags, writeOnly
}
func (fs *FS) Open(name string, flags uint32, context *fuse.Context) (fuseFile nodefs.File, status fuse.Status) {
cryptfs.Debug.Printf("Open(%s)\n", name)
iflags, writeOnly := fs.mangleOpenFlags(flags)
f, err := os.OpenFile(fs.GetPath(name), iflags, 0666)
if err != nil {
return nil, fuse.ToStatus(err)
}
return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
}
func (fs *FS) Create(path string, flags uint32, mode uint32, context *fuse.Context) (fuseFile nodefs.File, code fuse.Status) {
iflags, writeOnly := fs.mangleOpenFlags(flags)
f, err := os.OpenFile(fs.GetPath(path), iflags|os.O_CREATE, os.FileMode(mode))
if err != nil {
return nil, fuse.ToStatus(err)
}
return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
}
func (fs *FS) Chmod(path string, mode uint32, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Chmod(fs.EncryptPath(path), mode, context)
}
func (fs *FS) Chown(path string, uid uint32, gid uint32, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Chmod(fs.EncryptPath(path), gid, context)
}
func (fs *FS) Truncate(path string, offset uint64, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Truncate(fs.EncryptPath(path), offset, context)
}
func (fs *FS) Utimens(path string, Atime *time.Time, Mtime *time.Time, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Utimens(fs.EncryptPath(path), Atime, Mtime, context)
}
func (fs *FS) Readlink(name string, context *fuse.Context) (out string, code fuse.Status) {
return fs.FileSystem.Readlink(fs.EncryptPath(name), context)
}
func (fs *FS) Mknod(name string, mode uint32, dev uint32, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Mknod(fs.EncryptPath(name), mode, dev, context)
}
func (fs *FS) Mkdir(path string, mode uint32, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Mkdir(fs.EncryptPath(path), mode, context)
}
func (fs *FS) Unlink(name string, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Unlink(fs.EncryptPath(name), context)
}
func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Rmdir(fs.EncryptPath(name), context)
}
func (fs *FS) Symlink(pointedTo string, linkName string, context *fuse.Context) (code fuse.Status) {
// TODO symlink encryption
return fs.FileSystem.Symlink(fs.EncryptPath(pointedTo), fs.EncryptPath(linkName), context)
}
func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (codee fuse.Status) {
return fs.FileSystem.Rename(fs.EncryptPath(oldPath), fs.EncryptPath(newPath), context)
}
func (fs *FS) Link(orig string, newName string, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Link(fs.EncryptPath(orig), fs.EncryptPath(newName), context)
}
func (fs *FS) Access(name string, mode uint32, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Access(fs.EncryptPath(name), mode, context)
}
func (fs *FS) GetXAttr(name string, attr string, context *fuse.Context) ([]byte, fuse.Status) {
return nil, fuse.ENOSYS
}
func (fs *FS) SetXAttr(name string, attr string, data []byte, flags int, context *fuse.Context) fuse.Status {
return fuse.ENOSYS
}
func (fs *FS) ListXAttr(name string, context *fuse.Context) ([]string, fuse.Status) {
return nil, fuse.ENOSYS
}
func (fs *FS) RemoveXAttr(name string, attr string, context *fuse.Context) fuse.Status {
return fuse.ENOSYS
}