From fa3b126a23f42134e6c9cc1ae2ba9f8d2df97967 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 19 Apr 2013 18:05:04 -0300
Subject: BUG: stack overflow in vararg functions with many fixed parameters
called with few arguments
---
ldo.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/ldo.c b/ldo.c
index bbdffbac..47e80f8a 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.c,v 2.107 2012/08/28 18:30:45 roberto Exp roberto $
+** $Id: ldo.c,v 2.108.1.2 2013/04/19 21:03:23 roberto Exp $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -260,6 +260,7 @@ static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
StkId base, fixed;
lua_assert(actual >= nfixargs);
/* move fixed parameters to final position */
+ luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */
fixed = L->top - actual; /* first fixed argument */
base = L->top; /* final position of first argument */
for (i=0; i<nfixargs; i++) {
@@ -324,12 +325,18 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
case LUA_TLCL: { /* Lua function: prepare its call */
StkId base;
Proto *p = clLvalue(func)->p;
- luaD_checkstack(L, p->maxstacksize);
- func = restorestack(L, funcr);
n = cast_int(L->top - func) - 1; /* number of real arguments */
+ luaD_checkstack(L, p->maxstacksize);
for (; n < p->numparams; n++)
setnilvalue(L->top++); /* complete missing arguments */
- base = (!p->is_vararg) ? func + 1 : adjust_varargs(L, p, n);
+ if (!p->is_vararg) {
+ func = restorestack(L, funcr);
+ base = func + 1;
+ }
+ else {
+ base = adjust_varargs(L, p, n);
+ func = restorestack(L, funcr); /* previous call can change stack */
+ }
ci = next_ci(L); /* now 'enter' new function */
ci->nresults = nresults;
ci->func = func;
--
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