From: Mattias Engdegård <mattiase@acm.org>
Date: Thu, 7 Feb 2019 18:05:06 +0000 (+0100)
Subject: Check validity of rx submatch-n number
X-Git-Tag: emacs-27.0.90~2295
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2eafb4af55cc835694a0e747835b88145d20a94d;p=emacs.git

Check validity of rx submatch-n number

* lisp/emacs-lisp/rx.el (rx-submatch): Type and range check (Bug#34373).
---

diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index 8ef78fd69e6..2130e3e1aea 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -725,6 +725,8 @@ FORM is either `(repeat N FORM1)' or `(repeat N M FORMS...)'."
 (defun rx-submatch-n (form)
   "Parse and produce code from FORM, which is `(submatch-n N ...)'."
   (let ((n (nth 1 form)))
+    (unless (and (integerp n) (> n 0))
+      (error "rx `submatch-n' argument must be positive"))
     (concat "\\(?" (number-to-string n) ":"
 	    (if (= 3 (length form))
 		;; Only one sub-form.