From 8c5f2f24c7d7da0a2fceaf32aaa9e80d0b3b7c86 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Tue, 4 Sep 2018 16:30:50 +0200
Subject: [PATCH] Don't allow setting a property when the prototype's property
 is read-only.

---
 jsrun.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/jsrun.c b/jsrun.c
index b77e641..9fb256a 100644
--- a/jsrun.c
+++ b/jsrun.c
@@ -610,6 +610,8 @@ static void jsR_setproperty(js_State *J, js_Object *obj, const char *name)
 			if (J->strict)
 				if (ref->getter)
 					js_typeerror(J, "setting property '%s' that only has a getter", name);
+			if (ref->atts & JS_READONLY)
+				goto readonly;
 		}
 	}