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Diffstat (limited to 'internal')
-rw-r--r--internal/fusefrontend/file.go14
1 files changed, 13 insertions, 1 deletions
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 9bd05e6..277a844 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