std_scan_complete(): Catch some errors to avoid segfaults.

Check some variables for NULL before dereference to avoid segfaults due
to buggy drivers (and show error messages so these issues are noticed early).

diff --git a/src/std.c b/src/std.c
index 4af3c6816266aa91ed097957f1583614c888a7a3..fa668a7c8eba8efc552dbdf28610641d9f440df9 100644 (file)
--- a/src/std.c
+++ b/src/std.c
@@ -378,18 +378,29 @@ SR_PRIV GSList *std_dev_list(const struct sr_dev_driver *di)
  * }
  * @endcode
  *
- * @param di The driver instance to use.
+ * @param di The driver instance to use. Must not be NULL.
  * @param devices List of newly discovered devices (struct sr_dev_inst).
  *
  * @return The @p devices list.
  */
 SR_PRIV GSList *std_scan_complete(struct sr_dev_driver *di, GSList *devices)
 {
-       struct drv_context *drvc = di->context;
+       struct drv_context *drvc;
        GSList *l;
 
+       if (!di) {
+               sr_err("Invalid driver instance (di), cannot complete scan.");
+               return NULL;
+       }
+
+       drvc = di->context;
+
        for (l = devices; l; l = l->next) {
                struct sr_dev_inst *sdi = l->data;
+               if (!sdi) {
+                       sr_err("Invalid driver instance, cannot complete scan.");
+                       return NULL;
+               }
                sdi->driver = di;
        }