diff options
Diffstat (limited to 'cluefs_frontend/fe_file.go')
-rw-r--r-- | cluefs_frontend/fe_file.go | 152 |
1 files changed, 0 insertions, 152 deletions
diff --git a/cluefs_frontend/fe_file.go b/cluefs_frontend/fe_file.go deleted file mode 100644 index 58ab0dc..0000000 --- a/cluefs_frontend/fe_file.go +++ /dev/null @@ -1,152 +0,0 @@ -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.Skip:ib.Skip+ib.Length], req.Data) - blockLen := max(len(readResp.Data), int(ib.Skip+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 -} |