[#2831] move null check closer to place of effect

diff --git a/src/lib/dns/nsec3hash.cc b/src/lib/dns/nsec3hash.cc
index 279a2bd562e2338bb02a10be001e779e4399ca9c..c5fbd81f58c5fe4d99b673bdfc66cda08da06b3e 100644 (file)
--- a/src/lib/dns/nsec3hash.cc
+++ b/src/lib/dns/nsec3hash.cc
@@ -68,11 +68,10 @@ public:
                       static_cast<unsigned int>(algorithm_));
         }
 
-        if (salt_data == NULL) {
-            isc_throw(isc::BadValue, "salt data is NULL");
-        }
-
         if (salt_length > 0) {
+            if (salt_data == NULL) {
+                isc_throw(isc::BadValue, "salt data is NULL");
+            }
             salt_data_ = static_cast<uint8_t*>(std::malloc(salt_length));
             if (salt_data_ == NULL) {
                 throw std::bad_alloc();