hardcoresushi/libgocryptfs
1
0
Fork 0
Code Issues Pull Requests Releases Activity

pathiv: move derivedIVContainer into the package

Browse Source 
...under the new name "FileIVs".

This will also be used by forward mode.
This commit is contained in:
Jakob Unterwurzacher 2017-05-28 18:33:05 +02:00
parent 857507e8b1
commit d202a456f5
2 changed files with 29 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
internal/fusefrontend_reverse/rfile.go
View File

@ -33,11 +33,6 @@ type reverseFile struct {
var inodeTable syncmap.Map
type derivedIVContainer struct {
id []byte
block0IV []byte
}
func (rfs *ReverseFS) newFile(relPath string, flags uint32) (nodefs.File, fuse.Status) {
absPath, err := rfs.abs(rfs.decryptPath(relPath))
if err != nil {
@ -55,14 +50,13 @@ func (rfs *ReverseFS) newFile(relPath string, flags uint32) (nodefs.File, fuse.S
}
// See if we have that inode number already in the table
// (even if Nlink has dropped to 1)
var derivedIVs derivedIVContainer
var derivedIVs pathiv.FileIVs
v, found := inodeTable.Load(st.Ino)
if found {
tlog.Debug.Printf("ino%d: newFile: found in the inode table", st.Ino)
derivedIVs = v.(derivedIVContainer)
derivedIVs = v.(pathiv.FileIVs)
} else {
derivedIVs.id = pathiv.Derive(relPath, pathiv.PurposeFileID)
derivedIVs.block0IV = pathiv.Derive(relPath, pathiv.PurposeBlock0IV)
derivedIVs = pathiv.DeriveFile(relPath)
// Nlink > 1 means there is more than one path to this file.
// Store the derived values so we always return the same data,
// regardless of the path that is used to access the file.
@ -71,7 +65,7 @@ func (rfs *ReverseFS) newFile(relPath string, flags uint32) (nodefs.File, fuse.S
v, found = inodeTable.LoadOrStore(st.Ino, derivedIVs)
if found {
// Another thread has stored a different value before we could.
derivedIVs = v.(derivedIVContainer)
derivedIVs = v.(pathiv.FileIVs)
} else {
tlog.Debug.Printf("ino%d: newFile: Nlink=%d, stored in the inode table", st.Ino, st.Nlink)
}
@ -79,13 +73,13 @@ func (rfs *ReverseFS) newFile(relPath string, flags uint32) (nodefs.File, fuse.S
}
header := contentenc.FileHeader{
Version: contentenc.CurrentVersion,
ID: derivedIVs.id,
ID: derivedIVs.ID,
}
return &reverseFile{
File: nodefs.NewDefaultFile(),
fd: fd,
header: header,
block0IV: derivedIVs.block0IV,
block0IV: derivedIVs.Block0IV,
contentEnc: rfs.contentEnc,
}, fuse.OK
}

26
internal/pathiv/pathiv.go
View File

@ -6,13 +6,19 @@ import (
"github.com/rfjakob/gocryptfs/internal/nametransform"
)
// Purpose identifies for which purpose the IV will be used. This is mixed into the
// derivation.
type Purpose string
const (
PurposeDirIV Purpose = "DIRIV"
PurposeFileID Purpose = "FILEID"
// PurposeDirIV means the value will be used as a directory IV
PurposeDirIV Purpose = "DIRIV"
// PurposeFileID means the value will be used as the file ID in the file header
PurposeFileID Purpose = "FILEID"
// PurposeSymlinkIV means the value will be used as the IV for symlink encryption
PurposeSymlinkIV Purpose = "SYMLINKIV"
PurposeBlock0IV Purpose = "BLOCK0IV"
// PurposeBlock0IV means the value will be used as the IV of ciphertext block #0.
PurposeBlock0IV Purpose = "BLOCK0IV"
)
// Derive derives an IV from an encrypted path by hashing it with sha256
@ -22,3 +28,17 @@ func Derive(path string, purpose Purpose) []byte {
hash := sha256.Sum256(extended)
return hash[:nametransform.DirIVLen]
}
// FileIVs contains both IVs that are needed to create a file.
type FileIVs struct {
ID []byte
Block0IV []byte
}
// DeriveFile derives both IVs that are needed to create a file and returns them
// in a container struct.
func DeriveFile(path string) (fileIVs FileIVs) {
fileIVs.ID = Derive(path, PurposeFileID)
fileIVs.Block0IV = Derive(path, PurposeBlock0IV)
return fileIVs
}