hardcoresushi/libgocryptfs
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fusefrontend: write: consolidate and move encryption to contentenc

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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
This commit is contained in:
Jakob Unterwurzacher 2017-06-01 21:39:47 +02:00
parent 53b7c17261
commit a24faa3ba5
2 changed files with 27 additions and 21 deletions
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18
internal/contentenc/content.go
View File

@ -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.

30
internal/fusefrontend/file.go
View File

@ -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)