libgocryptfs/internal/fusefrontend/ctlsock_interface.go
Jakob Unterwurzacher c09bf1f228 fusefrontend: make DecryptPath() symlink-safe
DecryptPath is now symlink-safe through the use of *at()
functions.
2019-01-01 16:24:09 +01:00

76 lines
1.9 KiB
Go

package fusefrontend
import (
"fmt"
"path"
"strings"
"syscall"
"github.com/rfjakob/gocryptfs/internal/ctlsock"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
)
var _ ctlsock.Interface = &FS{} // Verify that interface is implemented.
// EncryptPath implements ctlsock.Backend
func (fs *FS) EncryptPath(plainPath string) (string, error) {
return fs.encryptPath(plainPath)
}
// DecryptPath implements ctlsock.Backend
func (fs *FS) DecryptPath(cipherPath string) (plainPath string, err error) {
dirfd, err := syscall.Open(fs.args.Cipherdir, syscall.O_RDONLY, 0)
if err != nil {
return "", err
}
defer syscall.Close(dirfd)
return fs.decryptPathAt(dirfd, cipherPath)
}
// decryptPathAt decrypts a ciphertext path relative to dirfd.
func (fs *FS) decryptPathAt(dirfd int, cipherPath string) (plainPath string, err error) {
if fs.args.PlaintextNames || cipherPath == "" {
return cipherPath, nil
}
parts := strings.Split(cipherPath, "/")
wd := dirfd
for i, part := range parts {
dirIV, err := nametransform.ReadDirIVAt(wd)
if err != nil {
fmt.Printf("ReadDirIV: %v\n", err)
return "", err
}
longPart := part
if nametransform.IsLongContent(part) {
longPart, err = nametransform.ReadLongNameAt(wd, part)
if err != nil {
fmt.Printf("ReadLongName: %v\n", err)
return "", err
}
}
name, err := fs.nameTransform.DecryptName(longPart, dirIV)
if err != nil {
fmt.Printf("DecryptName: %v\n", err)
return "", err
}
plainPath = path.Join(plainPath, name)
// Last path component? We are done.
if i == len(parts)-1 {
break
}
// Descend into next directory
oldWd := wd
wd, err = syscallcompat.Openat(wd, part, syscall.O_NOFOLLOW, 0)
if err != nil {
return "", err
}
// Unless we are in the first iteration, where dirfd is our wd, close
// the old working directory.
if i > 0 {
syscall.Close(oldWd)
}
}
return plainPath, nil
}