Rename frontend to "cluefs_frontend"

Enables adding another frontend later

4 files changed, 409 insertions, 0 deletions

diff --git a/cluefs_frontend/fe_checks.go b/cluefs_frontend/fe_checks.go
new file mode 100644
index 0000000..c555436
--- /dev/null
+++ b/cluefs_frontend/fe_checks.go
@@ -0,0 +1,31 @@
+package cluefs_frontend
+
+import (
+	"bazil.org/fuse/fs"
+)
+
+// Compile-time interface checks.
+var _ fs.FS = (*FS)(nil)
+var _ fs.FSStatfser = (*FS)(nil)
+
+var _ fs.Node = (*Dir)(nil)
+var _ fs.NodeCreater = (*Dir)(nil)
+var _ fs.NodeMkdirer = (*Dir)(nil)
+var _ fs.NodeRemover = (*Dir)(nil)
+var _ fs.NodeRenamer = (*Dir)(nil)
+var _ fs.HandleReadDirAller = (*Dir)(nil)
+
+var _ fs.HandleReader = (*File)(nil)
+var _ fs.HandleWriter = (*File)(nil)
+var _ fs.Node = (*File)(nil)
+var _ fs.NodeOpener = (*File)(nil)
+var _ fs.NodeSetattrer = (*File)(nil)
+
+func foo(h fs.HandleReadDirAller) {
+
+}
+
+func init() {
+	var d Dir
+	foo(&d)
+}
diff --git a/cluefs_frontend/fe_dir.go b/cluefs_frontend/fe_dir.go
new file mode 100644
index 0000000..65d92f1
--- /dev/null
+++ b/cluefs_frontend/fe_dir.go
@@ -0,0 +1,180 @@
+package cluefs_frontend
+
+// frontend sits between FUSE and ClueFS
+// and uses cryptfs for all crypto operations
+//
+//          cryptfs
+//             ^
+//             |
+//             v
+// FUSE <-> frontend <-> ClueFS
+//
+// This file handles directories
+
+import (
+	"fmt"
+	"github.com/rfjakob/gocryptfs/cryptfs"
+	"github.com/rfjakob/cluefs/lib/cluefs"
+	"bazil.org/fuse"
+	fusefs "bazil.org/fuse/fs"
+	"golang.org/x/net/context"
+)
+
+type Dir struct {
+	*cluefs.Dir
+	crfs *cryptfs.CryptFS
+}
+
+func NewDir(parent string, name string, fs *FS) *Dir {
+	cryptfs.Debug.Printf("NewDir parent=%s name=%s\n", parent, name)
+	return &Dir {
+		Dir: cluefs.NewDir(parent, name, fs.ClueFS),
+		crfs: fs.CryptFS,
+	}
+}
+
+func (d *Dir) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fusefs.Handle, error) {
+	cryptfs.Debug.Printf("Open\n")
+	h, err := d.Dir.Open(ctx, req, resp)
+	if err != nil {
+		return nil, err
+	}
+	clueDir := h.(*cluefs.Dir)
+
+	return &Dir {
+		Dir: clueDir,
+		crfs: d.crfs,
+	}, nil
+}
+
+func (d *Dir) Lookup(ctx context.Context, req *fuse.LookupRequest, resp *fuse.LookupResponse) (fusefs.Node, error) {
+	cryptfs.Debug.Printf("Lookup %s\n", req.Name)
+	req.Name = d.crfs.EncryptPath(req.Name)
+	node, err := d.Dir.Lookup(ctx, req, resp)
+	if err != nil {
+		return nil, err
+	}
+	clueDir, ok := node.(*cluefs.Dir)
+	if ok {
+		return &Dir {
+			Dir: clueDir,
+			crfs: d.crfs,
+		}, nil
+	} else {
+		resp.Attr.Size = d.crfs.PlainSize(resp.Attr.Size)
+		clueFile := node.(*cluefs.File)
+		return &File {
+			File: clueFile,
+			crfs: d.crfs,
+		}, nil
+	}
+}
+
+func (d *Dir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
+	cryptfs.Debug.Printf("ReadDirAll\n")
+	entries, err := d.Dir.ReadDirAll(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var decrypted []fuse.Dirent
+	for _, e := range entries {
+		if e.Name == "." || e.Name == ".." {
+			decrypted = append(decrypted, e)
+			continue
+		}
+		newName, err := d.crfs.DecryptPath(e.Name)
+		if err != nil {
+			fmt.Printf("ReadDirAll: Error decoding \"%s\": %s\n", e.Name, err.Error())
+			continue
+		}
+		e.Name = newName
+		decrypted = append(decrypted, e)
+	}
+	return decrypted, nil
+}
+
+func (d *Dir) Mkdir(ctx context.Context, req *fuse.MkdirRequest) (fusefs.Node, error) {
+	cryptfs.Debug.Printf("Mkdir %s\n", req.Name)
+	req.Name = d.crfs.EncryptPath(req.Name)
+	n, err := d.Dir.Mkdir(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	clueDir := n.(*cluefs.Dir)
+	return &Dir {
+		Dir: clueDir,
+		crfs: d.crfs,
+	}, nil
+}
+
+func (d *Dir) Remove(ctx context.Context, req *fuse.RemoveRequest) error {
+	cryptfs.Debug.Printf("Remove\n")
+	req.Name = d.crfs.EncryptPath(req.Name)
+	return d.Dir.Remove(ctx, req)
+}
+
+func (d *Dir) Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse) (fusefs.Node, fusefs.Handle, error) {
+	cryptfs.Debug.Printf("Create\n")
+	req.Flags, _ = fixFlags(req.Flags)
+	req.Name = d.crfs.EncryptPath(req.Name)
+	n, _, err := d.Dir.Create(ctx, req, resp)
+	if err != nil {
+		return nil, nil, err
+	}
+	clueFile := n.(*cluefs.File)
+	cryptFile := &File {
+		File: clueFile,
+		crfs: d.crfs,
+	}
+	return cryptFile, cryptFile, nil
+}
+func (d *Dir) Symlink(ctx context.Context, req *fuse.SymlinkRequest) (fusefs.Node, error) {
+	req.Target = d.crfs.EncryptPath(req.Target)
+	req.NewName = d.crfs.EncryptPath(req.NewName)
+	node, err := d.Dir.Symlink(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	clueDir, ok := node.(*cluefs.Dir)
+	if ok {
+		return &Dir {
+			Dir: clueDir,
+			crfs: d.crfs,
+		}, nil
+	} else {
+		clueFile := node.(*cluefs.File)
+		return &File {
+			File: clueFile,
+			crfs: d.crfs,
+		}, nil
+	}
+}
+// We need to overwrite Readlink for both Dir and File. Do both right here to keep them in sync.
+func (d *Dir) Readlink(ctx context.Context, req *fuse.ReadlinkRequest) (string, error) {
+	dest, err := d.Dir.Readlink(ctx, req)
+	if err != nil {
+		return "", err
+	}
+	return d.crfs.DecryptPath(dest)
+}
+func (d *File) Readlink(ctx context.Context, req *fuse.ReadlinkRequest) (string, error) {
+	dest, err := d.File.Readlink(ctx, req)
+	if err != nil {
+		return "", err
+	}
+	return d.crfs.DecryptPath(dest)
+}
+// We need to overwrite Rename for both Dir and File. Do both right here to keep them in sync.
+func (d *Dir) Rename(ctx context.Context, req *fuse.RenameRequest, newDir fusefs.Node) error {
+	req.OldName = d.crfs.EncryptPath(req.OldName)
+	req.NewName = d.crfs.EncryptPath(req.NewName)
+	destDir := newDir.(*Dir)
+	return d.Dir.Rename(ctx, req, destDir.Dir)
+}
+func (d *File) Rename(ctx context.Context, req *fuse.RenameRequest, newDir fusefs.Node) error {
+	req.OldName = d.crfs.EncryptPath(req.OldName)
+	req.NewName = d.crfs.EncryptPath(req.NewName)
+	destDir := newDir.(*Dir)
+	return d.File.Rename(ctx, req, destDir.Dir)
+}
diff --git a/cluefs_frontend/fe_file.go b/cluefs_frontend/fe_file.go
new file mode 100644
index 0000000..4c4e38a
--- /dev/null
+++ b/cluefs_frontend/fe_file.go
@@ -0,0 +1,152 @@
+package cluefs_frontend
+
+// frontend sits between FUSE and ClueFS
+// and uses cryptfs for all crypto operations
+//
+//          cryptfs
+//             ^
+//             |
+//             v
+// FUSE <-> frontend <-> ClueFS
+//
+// This file handles files access
+
+import (
+	"fmt"
+	"github.com/rfjakob/gocryptfs/cryptfs"
+	"github.com/rfjakob/cluefs/lib/cluefs"
+
+	"bazil.org/fuse"
+	fusefs "bazil.org/fuse/fs"
+	"golang.org/x/net/context"
+)
+
+func fixFlags(flags fuse.OpenFlags) (fuse.OpenFlags, bool) {
+	cryptfs.Debug.Printf("fixFlags: Before: %s\n", flags.String())
+	var writeOnly bool
+	// We always need read access to do read-modify-write cycles
+	if flags & fuse.OpenWriteOnly > 0 {
+		flags = flags &^ fuse.OpenWriteOnly
+		flags = flags | fuse.OpenReadWrite
+		writeOnly = true
+	}
+	// We also cannot open the file in append mode, we need to seek back for RMW
+	flags = flags &^ fuse.OpenAppend
+	cryptfs.Debug.Printf("fixFlags: After: %s\n", flags.String())
+	return flags, writeOnly
+}
+
+func max(x int, y int) int {
+	if x > y {
+		return x
+	}
+	return y
+}
+
+type File struct {
+	*cluefs.File
+	crfs *cryptfs.CryptFS
+	// Remember if the file is supposed to be write-only
+	writeOnly bool
+}
+
+func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fusefs.Handle, error) {
+	cryptfs.Debug.Printf("File.Open\n")
+
+	req.Flags, f.writeOnly = fixFlags(req.Flags)
+
+	h, err := f.File.Open(ctx, req, resp)
+	if err != nil {
+		return nil, err
+	}
+	clueFile := h.(*cluefs.File)
+	return &File {
+		File: clueFile,
+		crfs: f.crfs,
+	}, nil
+}
+
+func (f *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
+
+	cryptfs.Debug.Printf("Read: o=%d l=%d\n", req.Offset, req.Size)
+
+	// Read the backing ciphertext in one go
+	iblocks := f.crfs.SplitRange(uint64(req.Offset), uint64(req.Size))
+	var cipherReq fuse.ReadRequest
+	var cipherResp fuse.ReadResponse
+	o, l := f.crfs.JoinCiphertextRange(iblocks)
+	cipherResp.Data = make([]byte, int(l))
+	cipherReq.Offset = int64(o)
+	cipherReq.Size = int(l)
+	cryptfs.Debug.Printf("Read: cipherReq o=%d l=%d\n", o, l)
+	err := f.File.Read(ctx, &cipherReq, &cipherResp)
+	if err != nil {
+		return err
+	}
+
+	// Decrypt it
+	plaintext, err := f.crfs.DecryptBlocks(cipherResp.Data)
+	if err != nil {
+		resp.Data = plaintext
+		return err
+	}
+	// Crop down to relevant part
+	resp.Data = f.crfs.CropPlaintext(plaintext, iblocks)
+
+	return nil
+}
+
+func (f *File) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error {
+	cryptfs.Debug.Printf("File.Write\n")
+	resp.Size = 0
+	iblocks := f.crfs.SplitRange(uint64(req.Offset), uint64(len(req.Data)))
+	var blockData []byte
+	for _, ib := range iblocks {
+		if ib.IsPartial() {
+			// RMW
+			cryptfs.Debug.Printf("RMW\n")
+			blockData = make([]byte, f.crfs.PlainBS())
+			var readReq fuse.ReadRequest
+			var readResp fuse.ReadResponse
+			o, l := ib.PlaintextRange()
+			readReq.Offset = int64(o)
+			readReq.Size = int(l)
+			err := f.Read(ctx, &readReq, &readResp)
+			if err != nil {
+				return err
+			}
+			copy(blockData, readResp.Data)
+			copy(blockData[ib.Offset:ib.Offset+ib.Length], req.Data)
+			blockLen := max(len(readResp.Data), int(ib.Offset+ib.Length))
+			blockData = blockData[0:blockLen]
+		} else {
+			blockData = req.Data[0:f.crfs.PlainBS()]
+		}
+		ciphertext := f.crfs.EncryptBlock(blockData)
+		var partReq fuse.WriteRequest
+		var partResp fuse.WriteResponse
+		o, _ := ib.CiphertextRange()
+		partReq.Data = ciphertext
+		partReq.Offset = int64(o)
+		err := f.File.Write(ctx, &partReq, &partResp)
+		if err != nil {
+			fmt.Printf("Write failure: %s\n", err.Error())
+			return err
+		}
+		// Remove written data from the front of the request
+		cryptfs.Debug.Printf("req.Data[%d:%d]\n", int(ib.Length), len(req.Data))
+		req.Data = req.Data[int(ib.Length):len(req.Data)]
+		resp.Size += int(ib.Length)
+	}
+	return nil
+}
+
+func (f *File) Attr(ctx context.Context, attr *fuse.Attr) error {
+	cryptfs.Debug.Printf("Attr\n")
+	err := f.File.Node.Attr(ctx, attr)
+	if err != nil {
+		return err
+	}
+	attr.Size = f.crfs.PlainSize(attr.Size)
+	return nil
+}
diff --git a/cluefs_frontend/fe_fs.go b/cluefs_frontend/fe_fs.go
new file mode 100644
index 0000000..2b12da6
--- /dev/null
+++ b/cluefs_frontend/fe_fs.go
@@ -0,0 +1,46 @@
+package cluefs_frontend
+
+// frontend sits between FUSE and ClueFS
+// and uses cryptfs for all crypto operations
+//
+//          cryptfs
+//             ^
+//             |
+//             v
+// FUSE <-> frontend <-> ClueFS
+//
+// This file handles just the root directory
+
+import (
+	"github.com/rfjakob/gocryptfs/cryptfs"
+	"github.com/rfjakob/cluefs/lib/cluefs"
+	fusefs "bazil.org/fuse/fs"
+)
+
+type FS struct {
+	*cryptfs.CryptFS
+	*cluefs.ClueFS
+	backing string
+}
+
+type nullTracer struct {}
+
+func (nullTracer) Trace(op cluefs.FsOperTracer) {}
+
+func NewFS(key [16]byte, backing string, useOpenssl bool) (*FS, error) {
+	var tracer nullTracer
+	clfs, err := cluefs.NewClueFS(backing, tracer)
+	if err != nil {
+		return nil, err
+	}
+	return &FS {
+		CryptFS: cryptfs.NewCryptFS(key, useOpenssl),
+		ClueFS: clfs,
+		backing: backing,
+	}, nil
+}
+
+func (fs *FS) Root() (fusefs.Node, error) {
+	cryptfs.Debug.Printf("Root\n")
+	return NewDir("", fs.backing, fs), nil
+}