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authorJakob Unterwurzacher2017-06-01 21:39:47 +0200
committerJakob Unterwurzacher2017-06-01 22:19:27 +0200
commita24faa3ba52c66dfc1707da5c8d001f2adff9ccc (patch)
treea07a03444a1689a3c1c0fb97a18f245cacf289d7
parent53b7c17261dbf0aeb46ebb448f7c97d5c9fad986 (diff)
fusefrontend: write: consolidate and move encryption to contentenc
Collect all the plaintext and pass everything to contentenc in one call. This will allow easier parallization of the encryption. https://github.com/rfjakob/gocryptfs/issues/116
-rw-r--r--internal/contentenc/content.go18
-rw-r--r--internal/fusefrontend/file.go30
2 files changed, 27 insertions, 21 deletions
diff --git a/internal/contentenc/content.go b/internal/contentenc/content.go
index 524296f..80bcf54 100644
--- a/internal/contentenc/content.go
+++ b/internal/contentenc/content.go
@@ -149,6 +149,24 @@ func (be *ContentEnc) DecryptBlock(ciphertext []byte, blockNo uint64, fileID []b
return plaintext, nil
}
+// EncryptBlocks is like EncryptBlock but takes multiple plaintext blocks.
+func (be *ContentEnc) EncryptBlocks(plaintextBlocks [][]byte, firstBlockNo uint64, fileID []byte) []byte {
+ // Encrypt piecewise.
+ ciphertextBlocks := make([][]byte, len(plaintextBlocks))
+ for i, v := range plaintextBlocks {
+ ciphertextBlocks[i] = be.EncryptBlock(v, firstBlockNo+uint64(i), fileID)
+ }
+ // Concatenate ciphertext into a single byte array.
+ // Size the output buffer for the maximum possible size (all blocks complete)
+ // to allocations in out.Write()
+ tmp := make([]byte, len(plaintextBlocks)*int(be.CipherBS()))
+ out := bytes.NewBuffer(tmp[:0])
+ for _, v := range ciphertextBlocks {
+ out.Write(v)
+ }
+ return out.Bytes()
+}
+
// EncryptBlock - Encrypt plaintext using a random nonce.
// blockNo and fileID are used as associated data.
// The output is nonce + ciphertext + tag.
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 57ec9ba..ca1798b 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -272,22 +272,17 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
// re-read it after the RLock().
f.fileTableEntry.HeaderLock.RLock()
}
- fileID := f.fileTableEntry.ID
defer f.fileTableEntry.HeaderLock.RUnlock()
// Handle payload data
- status := fuse.OK
dataBuf := bytes.NewBuffer(data)
blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data)))
- writeChain := make([][]byte, len(blocks))
- var numOutBytes int
+ toEncrypt := make([][]byte, len(blocks))
for i, b := range blocks {
blockData := dataBuf.Next(int(b.Length))
// Incomplete block -> Read-Modify-Write
if b.IsPartial() {
// Read
- o := b.BlockPlainOff()
- var oldData []byte
- oldData, status = f.doRead(o, f.contentEnc.PlainBS())
+ oldData, status := f.doRead(b.BlockPlainOff(), f.contentEnc.PlainBS())
if status != fuse.OK {
tlog.Warn.Printf("ino%d fh%d: RMW read failed: %s", f.qIno.Ino, f.intFd(), status.String())
return 0, status
@@ -296,33 +291,26 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
blockData = f.contentEnc.MergeBlocks(oldData, blockData, int(b.Skip))
tlog.Debug.Printf("len(oldData)=%d len(blockData)=%d", len(oldData), len(blockData))
}
- // Encrypt
- blockData = f.contentEnc.EncryptBlock(blockData, b.BlockNo, fileID)
tlog.Debug.Printf("ino%d: Writing %d bytes to block #%d",
f.qIno.Ino, uint64(len(blockData))-f.contentEnc.BlockOverhead(), b.BlockNo)
- // Store output data in the writeChain
- writeChain[i] = blockData
- numOutBytes += len(blockData)
- }
- // Concatenenate all elements in the writeChain into one contiguous buffer
- tmp := make([]byte, numOutBytes)
- writeBuf := bytes.NewBuffer(tmp[:0])
- for _, w := range writeChain {
- writeBuf.Write(w)
+ // Write into the to-encrypt list
+ toEncrypt[i] = blockData
}
+ // Encrypt all blocks
+ ciphertext := f.contentEnc.EncryptBlocks(toEncrypt, blocks[0].BlockNo, f.fileTableEntry.ID)
// 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()
+ cOff := int64(blocks[0].BlockCipherOff())
if !f.fs.args.NoPrealloc {
- err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), int64(cOff), int64(writeBuf.Len()))
+ err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), cOff, int64(len(ciphertext)))
if err != nil {
tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.qIno.Ino, f.intFd(), err.Error())
return 0, fuse.ToStatus(err)
}
}
// Write
- _, err = f.fd.WriteAt(writeBuf.Bytes(), int64(cOff))
+ _, err = f.fd.WriteAt(ciphertext, cOff)
if err != nil {
tlog.Warn.Printf("doWrite: Write failed: %s", err.Error())
return 0, fuse.ToStatus(err)