external/connectivity: Check for null string before strcmp

The strcmp function with null string causes a crash. This occurs
when an entry is added to routing table that has a null interface.

Change-Id: I919975c8ab114000c1ae67a0a867e15f9934e21a
CRs-fixed: 253597

1 files changed, 4 insertions, 1 deletions

diff --git a/cnd/src/cnd_iproute2.cpp b/cnd/src/cnd_iproute2.cpp
index 590bcdb..5fa750a 100755
--- a/cnd/src/cnd_iproute2.cpp
+++ b/cnd/src/cnd_iproute2.cpp
@@ -81,7 +81,10 @@ enum Cmd_line_actions
 struct routingTableMapComparator {
   bool operator() (const uint8_t *string1, const uint8_t *string2) const
   {
-    return (strcmp((char *)string1, (char *)string2) < 0);
+    if (string1 && string2) {
+        return (strcmp((char *)string1, (char *)string2) < 0);
+    }
+    return false;
   }
 };