118 lines
2.3 KiB
Go
118 lines
2.3 KiB
Go
// Copyright (C) 2022 Marius Schellenberger
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package crypto
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import (
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"cachefs/pkg/provider"
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osp "cachefs/pkg/provider/os"
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"encoding/base64"
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"errors"
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"io/fs"
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"os"
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"path/filepath"
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"strings"
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)
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var _ provider.FS = (*FS)(nil)
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type FS struct {
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fs provider.FS
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cbc *aesCbc
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key []byte
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}
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func NewFS(fs provider.FS, key []byte) (*FS, error) {
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if len(key) != 32 {
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return nil, errors.New("encryption key length must be 32 bytes")
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}
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cbc, err := newAesCbc(key)
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if err != nil {
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return nil, err
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}
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return &FS{
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fs: fs,
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cbc: cbc,
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key: key,
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}, nil
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}
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func (fs *FS) encPath(path string) string {
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parts := strings.Split(path, "/")
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cparts := make([]string, len(parts))
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for i, p := range parts {
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if p == "" {
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continue
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}
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cparts[i] = base64.RawURLEncoding.EncodeToString(
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fs.cbc.encrypt([]byte(p)),
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)
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}
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return filepath.Join(cparts...)
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}
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func (fs *FS) decPath(path string) (string, error) {
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parts := strings.Split(path, "/")
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pparts := make([]string, len(parts))
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for i, p := range parts {
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b, err := base64.RawURLEncoding.DecodeString(p)
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if err != nil {
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return "", err
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}
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pparts[i] = string(fs.cbc.decrypt(b))
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}
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return filepath.Join(pparts...), nil
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}
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func (fs *FS) name(p string) string {
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return filepath.Join(fs.Root(), p)
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}
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func (fs *FS) Stat(p string) (fs.FileInfo, error) {
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fi, err := fs.fs.Stat(fs.encPath(p))
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return stat{FileInfo: fi, name: fs.name(p)}, err
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}
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func (fs *FS) Remove(p string) error {
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return fs.fs.Remove(fs.encPath(p))
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}
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func (fs *FS) Open(p string) (provider.File, error) {
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c := fs.encPath(p)
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fi, err := fs.fs.Stat(c)
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if err != nil {
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return nil, err
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}
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f, err := fs.fs.Open(c)
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if err != nil {
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return nil, err
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}
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return newFile(fs.key, p, fs, f, fi.IsDir())
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}
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func (fs *FS) OpenFile(p string, flags int, mode os.FileMode) (provider.File, error) {
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f, err := fs.fs.OpenFile(fs.encPath(p), flags, mode)
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if err != nil {
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return nil, err
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}
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return newFile(fs.key, p, fs, f, false)
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}
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func (fs *FS) MkdirAll(p string, mode os.FileMode) error {
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return fs.fs.MkdirAll(fs.encPath(p), mode)
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}
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func (fs *FS) Root() string {
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return fs.fs.Root()
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}
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func (fs *FS) Fstat(fd uintptr) (int64, error) {
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osp, ok := fs.fs.(*osp.FS)
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if ok {
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return osp.Fstat(fd)
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}
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return 0, provider.ErrFstat
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}
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func (fs *FS) Close() error {
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return nil
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}
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