Fix crashes when assigning timeouts as floats. New NSE utility function nseU_checkinteger

nse_nsock.cc

@@ -44,7 +44,7 @@ extern NmapOps o;
 typedef struct nse_nsock_udata
 {
   nsock_iod nsiod;
-  unsigned timeout;
+  int timeout;
 
   lua_State *thread;
 
@@ -739,9 +739,10 @@ static int l_get_info (lua_State *L)
 static int l_set_timeout (lua_State *L)
 {
   nse_nsock_udata *nu = check_nsock_udata(L, 1, false);
-  nu->timeout = luaL_checkinteger(L, 2);
-  if ((int) nu->timeout < -1) /* -1 is no timeout */
-    return luaL_error(L, "Negative timeout: %d", nu->timeout);
+  int timeout = nseU_checkinteger(L, 2);
+  if (timeout < -1) /* -1 is no timeout */
+    return luaL_error(L, "Negative timeout: %f", timeout);
+  nu->timeout = timeout;
   return nseU_success(L);
 }
 

nse_utility.cc

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <stdarg.h>
+#include <math.h>
 
 #include "Target.h"
 #include "portlist.h"
@@ -7,6 +8,16 @@
 #include "nse_main.h"
 #include "nse_utility.h"
 
+int nseU_checkinteger (lua_State *L, int arg)
+{
+  lua_Number n = luaL_checknumber(L, arg);
+  int i;
+  if (!lua_numbertointeger(floor(n), &i)) {
+    return luaL_error(L, "Number cannot be converted to an integer");
+  }
+  return i;
+}
+
 int nseU_traceback (lua_State *L)
 {
   if (lua_isstring(L, 1))

nse_utility.h

@@ -8,6 +8,12 @@ class Target;
 #include <stdint.h>
 #endif
 
+/* int nseU_checkinteger (lua_State *L, int arg)
+ *
+ * Replacement for luaL_checkinteger that does a floor operation first
+ */
+int nseU_checkinteger (lua_State *L, int arg);
+
 /* int nseU_traceback (lua_State *L)
  *
  * Traceback C Lua function.