From: Philipp Stephani <phst@google.com>
Date: Mon, 16 Apr 2018 06:45:27 +0000 (-0700)
Subject: Avoid undefined behavior in 'defvar' (Bug#31072)
X-Git-Tag: emacs-27.0.90~5169
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=9f2d21ca536ea7ca1da98e7bd57ae535ab394997;p=emacs.git

Avoid undefined behavior in 'defvar' (Bug#31072)

* src/eval.c (Fdefvar): Check that first argument is a symbol.
* test/src/eval-tests.el (defvar/bug31072): New unit test.
---

diff --git a/src/eval.c b/src/eval.c
index a6e1d86c4ab..90d8c335185 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -737,6 +737,8 @@ usage: (defvar SYMBOL &optional INITVALUE DOCSTRING)  */)
   sym = XCAR (args);
   tail = XCDR (args);
 
+  CHECK_SYMBOL (sym);
+
   if (!NILP (tail))
     {
       if (!NILP (XCDR (tail)) && !NILP (XCDR (XCDR (tail))))
diff --git a/test/src/eval-tests.el b/test/src/eval-tests.el
index 59da6b7cc30..319dd91c86a 100644
--- a/test/src/eval-tests.el
+++ b/test/src/eval-tests.el
@@ -113,4 +113,8 @@ crash/abort/malloc assert failure on the next test."
         (signal-hook-function #'ignore))
     (should-error (eval-tests--exceed-specbind-limit))))
 
+(ert-deftest defvar/bug31072 ()
+  "Check that Bug#31072 is fixed."
+  (should-error (eval '(defvar 1) t) :type 'wrong-type-argument))
+
 ;;; eval-tests.el ends here