diff options
| -rw-r--r-- | cryptfs/cryptfile.go | 18 | ||||
| -rw-r--r-- | cryptfs/cryptfs.go | 4 | ||||
| -rw-r--r-- | frontend/dir.go | 3 | ||||
| -rw-r--r-- | frontend/file.go | 75 |
4 files changed, 91 insertions, 9 deletions
diff --git a/cryptfs/cryptfile.go b/cryptfs/cryptfile.go index 0cd11da..98b6d12 100644 --- a/cryptfs/cryptfile.go +++ b/cryptfs/cryptfile.go @@ -115,14 +115,26 @@ func (ib *intraBlock) IsPartial() bool { return false } -// ciphertextRange - get byte range in ciphertext file corresponding to BlockNo +// CiphertextRange - get byte range in ciphertext file corresponding to BlockNo +// (complete block) func (ib *intraBlock) CiphertextRange() (offset int64, length int64) { return ib.BlockNo * ib.fs.cipherBS, ib.fs.cipherBS } -// CropBlock - crop a full plaintext block down to the relevant part +// PlaintextRange - get byte range in plaintext corresponding to BlockNo +// (complete block) +func (ib *intraBlock) PlaintextRange() (offset int64, length int64) { + return ib.BlockNo * ib.fs.plainBS, ib.fs.plainBS +} + +// CropBlock - crop a potentially larger plaintext block down to the relevant part func (ib *intraBlock) CropBlock(d []byte) []byte{ - return d[ib.Offset:ib.Offset+ib.Length] + lenHave := len(d) + lenWant := int(ib.Offset+ib.Length) + if lenHave < lenWant { + return d[ib.Offset:lenHave] + } + return d[ib.Offset:lenWant] } // Split a plaintext byte range into (possible partial) blocks diff --git a/cryptfs/cryptfs.go b/cryptfs/cryptfs.go index f5781e2..72eea61 100644 --- a/cryptfs/cryptfs.go +++ b/cryptfs/cryptfs.go @@ -55,6 +55,10 @@ func (fs *CryptFS) NewFile(f *os.File) *CryptFile { } } +func (be *CryptFS) PlainBS() int64 { + return be.plainBS +} + // DecryptName - decrypt filename func (be *CryptFS) decryptName(cipherName string) (string, error) { diff --git a/frontend/dir.go b/frontend/dir.go index ce64a5a..46be0db 100644 --- a/frontend/dir.go +++ b/frontend/dir.go @@ -103,6 +103,9 @@ func (d *Dir) Remove(ctx context.Context, req *fuse.RemoveRequest) error { func (d *Dir) Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse) (fusefs.Node, fusefs.Handle, error) { fmt.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 { diff --git a/frontend/file.go b/frontend/file.go index c5a02be..8014753 100644 --- a/frontend/file.go +++ b/frontend/file.go @@ -10,13 +10,40 @@ import ( "golang.org/x/net/context" ) +func fixFlags(flags fuse.OpenFlags) (fuse.OpenFlags, bool) { + fmt.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 + fmt.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) { - fmt.Printf("File.Open: f.crfs=%p\n", f.crfs) + fmt.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 @@ -29,32 +56,68 @@ func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenR } func (f *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error { - fmt.Printf("File.Read: f.crfs=%p\n", f.crfs) iblocks := f.crfs.SplitRange(req.Offset, int64(req.Size)) for _, ib := range iblocks { var partReq fuse.ReadRequest var partResp fuse.ReadResponse o, l := ib.CiphertextRange() + partReq.Offset = o partReq.Size = int(l) partResp.Data = make([]byte, int(l)) - partReq.Offset = o err := f.File.Read(ctx, &partReq, &partResp) if err != nil { return err } plaintext, err := f.crfs.DecryptBlock(partResp.Data) if err != nil { - fmt.Printf("Read: Block %d: %s\n", ib.BlockNo, err.Error()) + fmt.Printf("Read: Error reading block %d: %s\n", ib.BlockNo, err.Error()) return err } - plaintext = ib.CropBlock(partResp.Data) + plaintext = ib.CropBlock(plaintext) resp.Data = append(resp.Data, plaintext...) } return nil } func (f *File) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error { + fmt.Printf("File.Write\n") + resp.Size = 0 iblocks := f.crfs.SplitRange(req.Offset, int64(len(req.Data))) - iblocks = iblocks + var blockData []byte + for _, ib := range iblocks { + if ib.IsPartial() { + // RMW + blockData = make([]byte, f.crfs.PlainBS()) + var readReq fuse.ReadRequest + var readResp fuse.ReadResponse + o, l := ib.PlaintextRange() + readReq.Offset = 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 = 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 + req.Data = req.Data[len(blockData):len(req.Data)] + resp.Size += len(blockData) + } return nil } |