From 092f66fb0590f543ee5c45156ddabaddc7222a92 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 20 Jul 2020 15:55:18 -0300
Subject: Fixed bug: invalid mode can crash 'io.popen'

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

(limited to 'liolib.c')

diff --git a/liolib.c b/liolib.c
index 8a9e75cd..027d4bd0 100644
--- a/liolib.c
+++ b/liolib.c
@@ -277,6 +277,8 @@ static int io_popen (lua_State *L) {
   const char *filename = luaL_checkstring(L, 1);
   const char *mode = luaL_optstring(L, 2, "r");
   LStream *p = newprefile(L);
+  luaL_argcheck(L, ((mode[0] == 'r' || mode[0] == 'w') && mode[1] == '\0'),
+                   2, "invalid mode");
   p->f = l_popen(L, filename, mode);
   p->closef = &io_pclose;
   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
-- 
cgit v1.2.3-55-g6feb