Prevent monotime overflow

src/lib/time/compat_time.c

@@ -73,6 +73,7 @@ tor_sleep_msec(int msec)
 }
 #endif /* defined(TOR_UNIT_TESTS) */
 
+#define TEN_THOUSAND ((int64_t) (10 * 1000))
 #define ONE_MILLION ((int64_t) (1000 * 1000))
 #define ONE_BILLION ((int64_t) (1000 * 1000 * 1000))
 
@@ -522,6 +523,12 @@ monotime_init_internal(void)
   tor_assert(n <= INT64_MAX);
   tor_assert(d <= INT64_MAX);
 
+  while (d > TEN_THOUSAND) {
+    n /= 10;
+    d /= 10;
+  }
+  simplify_fraction64(&n, &d);
+
   nsec_per_tick_numer = (int64_t) n;
   nsec_per_tick_denom = (int64_t) d;