plan 8: fuzz decoders; fold ẞ and invalid UTF-8 correctly, refuse non-UTF-8 paths in krino new

1 files changed, 6 insertions, 0 deletions

diff --git a/internal/config/skel.go b/internal/config/skel.go
index 65d9f95..ca914e3 100644
--- a/internal/config/skel.go
+++ b/internal/config/skel.go
@@ -10,6 +10,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"unicode/utf8"
 
 	"krino/internal/sexp"
 	"krino/internal/xdg"
@@ -66,6 +67,11 @@ func NewDir(mainFile, name, path string) (string, error) {
 	if err != nil {
 		return "", err
 	}
+	// The path is written into the new file, and config files are UTF-8
+	// text (the reader refuses anything else).
+	if !utf8.ValidString(abs) {
+		return "", fmt.Errorf("%q is not valid UTF-8; krino's config is UTF-8 text, so rename the directory first", abs)
+	}
 	if fi, err := os.Stat(abs); err != nil || !fi.IsDir() {
 		return "", fmt.Errorf("%s is not a directory", abs)
 	}