Clear wpa_supplicant configuration keys explicitly

Use an explicit memset call to clear any wpa_supplicant configuration
parameter that contains private information like keys or identity. This
brings in an additional layer of protection by reducing the length of
time this type of private data is kept in memory.

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

src/utils/common.h

@@ -535,6 +535,10 @@ void int_array_add_unique(int **res, int a);
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
 
+void str_clear_free(char *str);
+void bin_clear_free(void *bin, size_t len);
+
+
 /*
  * gcc 4.4 ends up generating strict-aliasing warnings about some very common
  * networking socket uses that do not really result in a real problem and