refactor(cli): rename operator command to tht

2026-08-15 21:56:40 +02:00
parent 460caa550c
commit aa8a2e9278
49 changed files with 303 additions and 261 deletions
@@ -0,0 +1,102 @@
+// Package safeio reads and writes local files without following symlinked path components.
+package safeio
+
+import (
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"unicode/utf8"
+)
+
+var ErrUnsafeFile = errors.New("unsafe file")
+
+// ValidateCanonicalPath rejects relative or lexically non-canonical paths before they are opened.
+func ValidateCanonicalPath(path string) error {
+	if !filepath.IsAbs(path) || filepath.Clean(path) != path || strings.Contains(path, string(filepath.Separator)+".."+string(filepath.Separator)) {
+		return ErrUnsafeFile
+	}
+	return nil
+}
+
+func readBoundedRegularFile(path string, file *os.File, maximum int64) ([]byte, error) {
+	if maximum < 0 || maximum == int64(^uint64(0)>>1) {
+		return nil, ErrUnsafeFile
+	}
+	info, err := file.Stat()
+	if err != nil || !info.Mode().IsRegular() || !hasSingleLink(info) {
+		return nil, ErrUnsafeFile
+	}
+	contents, err := io.ReadAll(io.LimitReader(file, maximum+1))
+	if err != nil || int64(len(contents)) > maximum {
+		return nil, ErrUnsafeFile
+	}
+	after, err := file.Stat()
+	if err != nil || !after.Mode().IsRegular() || !hasSingleLink(after) || !os.SameFile(info, after) {
+		return nil, ErrUnsafeFile
+	}
+	current, err := os.Stat(path)
+	if err != nil || !os.SameFile(info, current) {
+		return nil, ErrUnsafeFile
+	}
+	return contents, nil
+}
+
+func ReadCanonicalUTF8(path string, maximum int64) (string, error) {
+	contents, err := ReadCanonicalRegular(path, maximum)
+	if err != nil {
+		return "", err
+	}
+	if !utf8.Valid(contents) {
+		return "", ErrUnsafeFile
+	}
+	return string(contents), nil
+}
+
+func WriteCanonicalNewFile(path string, contents []byte, mode os.FileMode) error {
+	if err := ValidateCanonicalPath(path); err != nil {
+		return err
+	}
+	parent := filepath.Dir(path)
+	if err := requireCanonicalDirectory(parent); err != nil {
+		return err
+	}
+	if info, err := os.Lstat(path); err == nil {
+		if !info.Mode().IsRegular() || info.Mode()&os.ModeSymlink != 0 || info.Mode()&os.ModeType != 0 {
+			return ErrUnsafeFile
+		}
+		return ErrUnsafeFile
+	} else if !errors.Is(err, os.ErrNotExist) {
+		return ErrUnsafeFile
+	}
+	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, mode)
+	if err != nil {
+		return ErrUnsafeFile
+	}
+	defer file.Close()
+	if _, err := file.Write(contents); err != nil {
+		_ = os.Remove(path)
+		return ErrUnsafeFile
+	}
+	if err := file.Sync(); err != nil {
+		_ = os.Remove(path)
+		return ErrUnsafeFile
+	}
+	return nil
+}
+
+func requireCanonicalDirectory(path string) error {
+	if err := ValidateCanonicalPath(path); err != nil {
+		return err
+	}
+	resolved, err := filepath.EvalSymlinks(path)
+	if err != nil || resolved != path {
+		return ErrUnsafeFile
+	}
+	info, err := os.Stat(path)
+	if err != nil || !info.IsDir() {
+		return ErrUnsafeFile
+	}
+	return nil
+}