106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
package fusefrontend
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import (
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"fmt"
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"path"
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"path/filepath"
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"strings"
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"syscall"
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"github.com/rfjakob/gocryptfs/internal/ctlsock"
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"github.com/rfjakob/gocryptfs/internal/nametransform"
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"github.com/rfjakob/gocryptfs/internal/syscallcompat"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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var _ ctlsock.Interface = &FS{} // Verify that interface is implemented.
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// EncryptPath implements ctlsock.Backend
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//
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// Symlink-safe through openBackingDir().
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func (fs *FS) EncryptPath(plainPath string) (string, error) {
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if plainPath == "" {
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// Empty string gets encrypted as empty string
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return plainPath, nil
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}
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if fs.args.PlaintextNames {
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return plainPath, nil
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}
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// Encrypt path level by level using openBackingDir. Pretty inefficient,
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// but does not matter here.
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parts := strings.Split(plainPath, "/")
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wd := ""
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cPath := ""
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for _, part := range parts {
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wd = filepath.Join(wd, part)
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dirfd, cName, err := fs.openBackingDir(wd)
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if err != nil {
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return "", err
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}
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syscall.Close(dirfd)
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cPath = filepath.Join(cPath, cName)
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}
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tlog.Debug.Printf("encryptPath '%s' -> '%s'", plainPath, cPath)
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return cPath, nil
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}
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// DecryptPath implements ctlsock.Backend
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//
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// DecryptPath is symlink-safe because openBackingDir() and decryptPathAt()
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// are symlink-safe.
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func (fs *FS) DecryptPath(cipherPath string) (plainPath string, err error) {
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dirfd, _, err := fs.openBackingDir("")
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if err != nil {
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return "", err
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}
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defer syscall.Close(dirfd)
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return fs.decryptPathAt(dirfd, cipherPath)
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}
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// decryptPathAt decrypts a ciphertext path relative to dirfd.
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//
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// Symlink-safe through ReadDirIVAt() and ReadLongNameAt().
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func (fs *FS) decryptPathAt(dirfd int, cipherPath string) (plainPath string, err error) {
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if fs.args.PlaintextNames || cipherPath == "" {
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return cipherPath, nil
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}
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parts := strings.Split(cipherPath, "/")
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wd := dirfd
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for i, part := range parts {
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dirIV, err := nametransform.ReadDirIVAt(wd)
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if err != nil {
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fmt.Printf("ReadDirIV: %v\n", err)
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return "", err
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}
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longPart := part
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if nametransform.IsLongContent(part) {
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longPart, err = nametransform.ReadLongNameAt(wd, part)
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if err != nil {
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fmt.Printf("ReadLongName: %v\n", err)
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return "", err
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}
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}
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name, err := fs.nameTransform.DecryptName(longPart, dirIV)
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if err != nil {
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fmt.Printf("DecryptName: %v\n", err)
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return "", err
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}
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plainPath = path.Join(plainPath, name)
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// Last path component? We are done.
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if i == len(parts)-1 {
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break
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}
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// Descend into next directory
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wd, err = syscallcompat.Openat(wd, part, syscall.O_NOFOLLOW|syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
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if err != nil {
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return "", err
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}
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// Yes this is somewhat wasteful in terms of used file descriptors:
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// we keep them all open until the function returns. But it is simple
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// and reliable.
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defer syscall.Close(wd)
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}
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return plainPath, nil
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}
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