diff options
| -rw-r--r-- | internal/fusefrontend/file.go | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go index 5be0872..abb675c 100644 --- a/internal/fusefrontend/file.go +++ b/internal/fusefrontend/file.go @@ -277,6 +277,7 @@ func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) { // If the file ID is not cached, read it from disk if f.fileTableEntry.ID == nil { if err := f.LockSharedStorage(unix.F_WRLCK, 0, contentenc.HeaderLen); err != nil { + tlog.Warn.Printf("ino%d: LockSharedStorage(F_WRLCK, %d, %d)failed: %v", 0, f.qIno.Ino, contentenc.HeaderLen, err) return 0, fs.ToErrno(err) } var err error @@ -302,7 +303,19 @@ func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) { // Handle payload data dataBuf := bytes.NewBuffer(data) blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data))) + cOff, lkLen := blocks[0].JointCiphertextRange(blocks) toEncrypt := make([][]byte, len(blocks)) + + // As we must write complete ciphertext blocks (except at EOF), non-overlapping + // plaintext writes can overlap in the ciphertext. + // And because overlapping writes can turn the data into data soup (see + // TestPoCTornWrite) we serialize them using fcntl locking. + if err := f.LockSharedStorage(unix.F_WRLCK, int64(cOff), int64(lkLen)); err != nil { + tlog.Warn.Printf("ino%d: LockSharedStorage(F_WRLCK, %d, %d) failed: %v", f.qIno.Ino, cOff, int64(lkLen), err) + return 0, fs.ToErrno(err) + } + defer f.LockSharedStorage(unix.F_UNLCK, int64(cOff), int64(lkLen)) + for i, b := range blocks { blockData := dataBuf.Next(int(b.Length)) // Incomplete block -> Read-Modify-Write @@ -327,7 +340,6 @@ func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) { // Preallocate so we cannot run out of space in the middle of the write. // This prevents partially written (=corrupt) blocks. var err error - cOff := blocks[0].BlockCipherOff() // f.fd.WriteAt & syscallcompat.EnospcPrealloc take int64 offsets! if cOff > math.MaxInt64 { return 0, syscall.EFBIG |