[tor-commits] [tor/master] Detect an unlikely integer overflow.

[nickm at torproject.org]

commit b058f64cc002b44e6dd48616ca3163a01c3f3e14
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Sep 27 16:30:02 2018 -0400

    Detect an unlikely integer overflow.
---
 src/feature/stats/geoip_stats.c | 5 ++++-
 src/lib/geoip/country.h         | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/feature/stats/geoip_stats.c b/src/feature/stats/geoip_stats.c
index 3e647bd46..1a4f8ddfb 100644
--- a/src/feature/stats/geoip_stats.c
+++ b/src/feature/stats/geoip_stats.c
@@ -265,7 +265,10 @@ geoip_note_client_seen(geoip_client_action_t action,
     int country_idx = geoip_get_country_by_addr(addr);
     if (country_idx < 0)
       country_idx = 0; /** unresolved requests are stored at index 0. */
-    increment_v3_ns_request(country_idx);
+    IF_BUG_ONCE(country_idx > COUNTRY_MAX) {
+      return;
+    }
+    increment_v3_ns_request((country_t) country_idx);
   }
 }
 
diff --git a/src/lib/geoip/country.h b/src/lib/geoip/country.h
index e4ad0752b..080c15602 100644
--- a/src/lib/geoip/country.h
+++ b/src/lib/geoip/country.h
@@ -11,4 +11,6 @@
 /** A signed integer representing a country code. */
 typedef int16_t country_t;
 
+#define COUNTRY_MAX INT16_MAX
+
 #endif