diff --git a/lib/StaticAnalyzer/Checkers/CStringChecker.cpp b/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
index 4eb189e..bd40337 100644
--- a/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -1033,6 +1033,21 @@
   if (stateNonZeroSize) {
     state = stateNonZeroSize;
 
+    // Ensure the destination is not null. If it is NULL there will be a
+    // NULL pointer dereference.
+    state = checkNonNull(C, state, Dest, destVal);
+    if (!state)
+      return;
+
+    // Get the value of the Src.
+    SVal srcVal = state->getSVal(Source, LCtx);
+
+    // Ensure the source is not null. If it is NULL there will be a
+    // NULL pointer dereference.
+    state = checkNonNull(C, state, Source, srcVal);
+    if (!state)
+      return;
+
     // Ensure the accesses are valid and that the buffers do not overlap.
     const char * const writeWarning =
       "Memory copy function overflows destination buffer";
@@ -2018,6 +2033,12 @@
     return;
   }
 
+  // Ensure the memory area is not null.
+  // If it is NULL there will be a NULL pointer dereference.
+  State = checkNonNull(C, StateNonZeroSize, Mem, MemVal);
+  if (!State)
+    return;
+
   State = CheckBufferAccess(C, State, Size, Mem);
   if (!State)
     return;