CPP: Add a test case involving the std::string constructor.

cpp/ql/test/query-tests/Security/CWE/CWE-131/semmle/NoSpaceForZeroTerminator/NoSpaceForZeroTerminator.expected

@@ -1,3 +1,4 @@
+| test2.cpp:35:28:35:33 | call to malloc | This allocation does not include space to null-terminate the string. |
 | test.c:16:20:16:25 | call to malloc | This allocation does not include space to null-terminate the string. |
 | test.c:32:20:32:25 | call to malloc | This allocation does not include space to null-terminate the string. |
 | test.c:49:20:49:25 | call to malloc | This allocation does not include space to null-terminate the string. |

cpp/ql/test/query-tests/Security/CWE/CWE-131/semmle/NoSpaceForZeroTerminator/test2.cpp

@@ -0,0 +1,38 @@
+
+///// Library functions //////
+
+typedef unsigned long size_t;
+
+void *malloc(size_t size);
+void free(void *ptr);
+size_t strlen(const char *s);
+
+namespace std
+{
+	template<class charT> struct char_traits;
+
+	template <class T> class allocator {
+	public:
+		allocator() throw();
+	};
+	
+	template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+	class basic_string {
+	public:
+		explicit basic_string(const Allocator& a = Allocator());
+		basic_string(const charT* s, const Allocator& a = Allocator());
+
+		const charT* c_str() const;
+	};
+
+	typedef basic_string<char> string;
+}
+
+//// Test code /////
+
+void bad1(char *str) {
+    // BAD -- Not allocating space for '\0' terminator
+    char *buffer = (char *)malloc(strlen(str));
+    std::string str2(buffer);
+    free(buffer);
+}