Skip to content

fix: validate embedded app paths with filepath.IsLocal #2721

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
dunglas wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

fix: validate embedded app paths with filepath.IsLocal #2721

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
48 changes: 3 additions & 45 deletions embed.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,10 +10,8 @@ import (
"io/fs"
"log"
"os"
"path"
"path/filepath"
"runtime"
"strings"
"time"
)

Expand Down Expand Up @@ -75,11 +73,10 @@ func untar(dir string) (err error) {
// Ignore it.
continue
}
rel, err := nativeRelPath(f.Name)
if err != nil {
return fmt.Errorf("tar file contained invalid name %q: %v", f.Name, err)
if !filepath.IsLocal(f.Name) {
return fmt.Errorf("tar file contained invalid name %q", f.Name)
}
abs := filepath.Join(dir, rel)
abs := filepath.Join(dir, f.Name)

fi := f.FileInfo()
mode := fi.Mode()
Expand Down Expand Up @@ -155,42 +152,3 @@ func untar(dir string) (err error) {
}
return nil
}

// nativeRelPath verifies that p is a non-empty relative path
// using either slashes or the buildlet's native path separator,
// and returns it canonicalized to the native path separator.
func nativeRelPath(p string) (string, error) {
if p == "" {
return "", errors.New("path not provided")
}

if filepath.Separator != '/' && strings.Contains(p, string(filepath.Separator)) {
clean := filepath.Clean(p)
if filepath.IsAbs(clean) {
return "", fmt.Errorf("path %q is not relative", p)
}
if clean == ".." || strings.HasPrefix(clean, ".."+string(filepath.Separator)) {
return "", fmt.Errorf("path %q refers to a parent directory", p)
}
if strings.HasPrefix(p, string(filepath.Separator)) || filepath.VolumeName(clean) != "" {
// On Windows, this catches semi-relative paths like "C:" (meaning “the
// current working directory on volume C:”) and "\windows" (meaning “the
// windows subdirectory of the current drive letter”).
return "", fmt.Errorf("path %q is relative to volume", p)
}
return p, nil
}

clean := path.Clean(p)
if path.IsAbs(clean) {
return "", fmt.Errorf("path %q is not relative", p)
}
if clean == ".." || strings.HasPrefix(clean, "../") {
return "", fmt.Errorf("path %q refers to a parent directory", p)
}
canon := filepath.FromSlash(p)
if filepath.VolumeName(canon) != "" {
return "", fmt.Errorf("path %q begins with a native volume name", p)
}
return canon, nil
}
Loading