libgocryptfs/internal/fusefrontend_reverse/diriv.go
Jakob Unterwurzacher be9dfe3a89 reverse: implement dynamic diriv
Introduce a unique per-directory diriv that is generated
by hashing the encrypted directory path.
2016-09-25 16:43:17 +02:00

43 lines
1023 B
Go

package fusefrontend_reverse
import (
"crypto/sha256"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/rfjakob/gocryptfs/internal/nametransform"
)
// deriveDirIV derives the DirIV from the directory path by simply hashing it
func deriveDirIV(dirPath string) []byte {
hash := sha256.Sum256([]byte(dirPath))
return hash[:nametransform.DirIVLen]
}
type dirIVFile struct {
// Embed nodefs.defaultFile for a ENOSYS implementation of all methods
nodefs.File
// file content
content []byte
}
func NewDirIVFile(dirPath string) (nodefs.File, fuse.Status) {
return &dirIVFile{
File: nodefs.NewDefaultFile(),
content: deriveDirIV(dirPath),
}, fuse.OK
}
// Read - FUSE call
func (f *dirIVFile) Read(buf []byte, off int64) (resultData fuse.ReadResult, status fuse.Status) {
if off >= int64(len(f.content)) {
return nil, fuse.OK
}
end := int(off) + len(buf)
if end > len(f.content) {
end = len(f.content)
}
return fuse.ReadResultData(f.content[off:end]), fuse.OK
}