diff --git a/tracks.c b/tracks.c
index 516fbef..674be4a 100644
--- a/tracks.c
+++ b/tracks.c
@@ -20,6 +20,7 @@
 #include <string.h>
 #include <assert.h>
 #include <ctype.h>
+#include <limits.h>
 #include <math.h>
 
 #include "puzzles.h"
@@ -196,6 +197,8 @@ static const char *validate_params(const game_params *params, bool full)
      */
     if (params->w < 4 || params->h < 4)
         return "Width and height must both be at least four";
+    if (params->w > INT_MAX / params->h)
+        return "Width times height must not be unreasonably large";
     return NULL;
 }