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From:   Christian Eggers <ceggers@arri.de>
To:     <linux-bluetooth@vger.kernel.org>
CC:     Christian Eggers <ceggers@arri.de>
Subject: [PATCH BlueZ v2 7/9] client/gatt: proxy_property_changed: check for NULL iterator
Date:   Fri, 23 Sep 2022 16:58:12 +0200
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The passed iterator can be NULL as in
gdbus/client.c::properties_changed():
...
   proxy->prop_func(..., ..., iter=NULL, ...)
   +--client/gatt.c::proxy_property_changed(..., ..., iter, ...);
      +--dbus_message_iter_get_arg_type(iter);
...
---
 client/gatt.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/client/gatt.c b/client/gatt.c
index efd736b2359a..e945b524b071 100644
--- a/client/gatt.c
+++ b/client/gatt.c
@@ -3003,17 +3003,20 @@ static void proxy_property_changed(GDBusProxy *proxy, const char *name,
 			chrc->path, bt_uuidstr_to_str(chrc->uuid), name);
 
 	if (!strcmp(name, "Value")) {
-		DBusMessageIter array;
-		uint8_t *value;
-		int len;
+		uint8_t *value = "";  /*don't pass NULL to write_value() */
+		int len = 0;
+
+		if (iter && dbus_message_iter_get_arg_type(iter) ==
+				DBUS_TYPE_ARRAY) {
+			DBusMessageIter array;
 
-		if (dbus_message_iter_get_arg_type(iter) == DBUS_TYPE_ARRAY) {
 			dbus_message_iter_recurse(iter, &array);
 			dbus_message_iter_get_fixed_array(&array, &value, &len);
-			write_value(&chrc->value_len, &chrc->value, value, len,
-					0, chrc->max_val_len);
-			bt_shell_hexdump(value, len);
 		}
+
+		write_value(&chrc->value_len, &chrc->value, value, len,
+				0, chrc->max_val_len);
+		bt_shell_hexdump(value, len);
 	}
 
 	g_dbus_emit_property_changed(conn, chrc->path, CHRC_INTERFACE, name);
-- 
2.35.3