base64: Use secure buffers

Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/base64.c

@@ -78,6 +78,8 @@ ssh_buffer base64_to_bin(const char *source) {
   }
 
   buffer = ssh_buffer_new();
+  /* base64 buffer often used to contain sensitive data */
+  ssh_buffer_set_secure(buffer);
   if (buffer == NULL) {
     SAFE_FREE(base64);
     return NULL;