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package cryptfs
import (
"fmt"
"io/ioutil"
"path/filepath"
"strings"
)
// readDirIV - read the "gocryptfs.diriv" file from "dir" (absolute path)
func (be *CryptFS) readDirIV(dir string) (iv []byte, err error) {
ivfile := filepath.Join(dir, DIRIV_FILENAME)
iv, err = ioutil.ReadFile(ivfile)
if err != nil {
Warn.Printf("readDirIV: %v\n", err)
return nil, err
}
if len(iv) != DIRIV_LEN {
return nil, fmt.Errorf("readDirIV: Invalid length %d\n", len(iv))
}
return iv, nil
}
// WriteDirIV - create diriv file inside "dir" (absolute path)
// This function is exported because it is used from pathfs_frontend
func (be *CryptFS) WriteDirIV(dir string) error {
iv := RandBytes(DIRIV_LEN)
file := filepath.Join(dir, DIRIV_FILENAME)
// 0444 permissions: the file is not secret but should not be written to
return ioutil.WriteFile(file, iv, 0444)
}
// EncryptPathDirIV - encrypt path using CBC with DirIV
func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string) (string, error) {
if be.plaintextNames {
return plainPath, nil
}
// Empty string means root directory
if plainPath == "" {
return plainPath, nil
}
var wd = rootDir
var encryptedNames []string
plainNames := strings.Split(plainPath, "/")
for _, plainName := range plainNames {
iv, err := be.readDirIV(wd)
if err != nil {
return "", err
}
encryptedName := be.encryptName(plainName, iv)
encryptedNames = append(encryptedNames, encryptedName)
wd = filepath.Join(wd, encryptedName)
}
return filepath.Join(encryptedNames...), nil
}
// DecryptPathDirIV - encrypt path using CBC with DirIV
func (be *CryptFS) DecryptPathDirIV(encryptedPath string, rootDir string) (string, error) {
if be.plaintextNames {
return encryptedPath, nil
}
var wd = rootDir
var plainNames []string
encryptedNames := strings.Split(encryptedPath, "/")
for _, encryptedName := range encryptedNames {
iv, err := be.readDirIV(wd)
if err != nil {
return "", err
}
plainName, err := be.decryptName(encryptedName, iv)
if err != nil {
return "", err
}
plainNames = append(plainNames, plainName)
wd = filepath.Join(wd, encryptedName)
}
return filepath.Join(plainNames...), nil
}
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