Explicit limit for number of results in a call

The parameter 'nresults' in 'lua_call' and similar functions has a
limit of 250. It already had an undocumented (and unchecked) limit of
SHRT_MAX, but it is seldom larger than 2.

1 files changed, 7 insertions, 2 deletions

diff --git a/lapi.c b/lapi.c
index f00bd53f..dbd291d7 100644
--- a/lapi.c
+++ b/lapi.c
@@ -1022,10 +1022,15 @@ LUA_API int lua_setiuservalue (lua_State *L, int idx, int n) {
 */
 
 
+#define MAXRESULTS      250
+
+
 #define checkresults(L,na,nr) \
-     api_check(L, (nr) == LUA_MULTRET \
+     (api_check(L, (nr) == LUA_MULTRET \
                || (L->ci->top.p - L->top.p >= (nr) - (na)), \
-        "results from function overflow current stack size")
+        "results from function overflow current stack size"), \
+      api_check(L, LUA_MULTRET <= (nr) && (nr) <= MAXRESULTS,  \
+                   "invalid number of results"))
 
 
 LUA_API void lua_callk (lua_State *L, int nargs, int nresults,