Add wpabuf_clear_free() to allow clearing of freed memory

This can be useful when a wpabuf is used to store private data that
should not be left in heap after use.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/utils/wpabuf.c

@@ -205,6 +205,15 @@ void wpabuf_free(struct wpabuf *buf)
 }
 
 
+void wpabuf_clear_free(struct wpabuf *buf)
+{
+	if (buf) {
+		os_memset(wpabuf_mhead(buf), 0, wpabuf_len(buf));
+		wpabuf_free(buf);
+	}
+}
+
+
 void * wpabuf_put(struct wpabuf *buf, size_t len)
 {
 	void *tmp = wpabuf_mhead_u8(buf) + wpabuf_len(buf);

src/utils/wpabuf.h

@@ -32,6 +32,7 @@ struct wpabuf * wpabuf_alloc_ext_data(u8 *data, size_t len);
 struct wpabuf * wpabuf_alloc_copy(const void *data, size_t len);
 struct wpabuf * wpabuf_dup(const struct wpabuf *src);
 void wpabuf_free(struct wpabuf *buf);
+void wpabuf_clear_free(struct wpabuf *buf);
 void * wpabuf_put(struct wpabuf *buf, size_t len);
 struct wpabuf * wpabuf_concat(struct wpabuf *a, struct wpabuf *b);
 struct wpabuf * wpabuf_zeropad(struct wpabuf *buf, size_t len);