[PATCH v4 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change()

[Hans de Goede <hdegoede@xxxxxxxxxx>]

When ucsi_init() fails, ucsi->connector is NULL, yet in case of
ucsi_acpi we may still get events which cause the ucs_acpi code to call
ucsi_connector_change(), which then derefs the NULL ucsi->connector
pointer.

Fix this by not setting ucsi->ntfy inside ucsi_init() until ucsi_init()
has succeeded, so that ucsi_connector_change() ignores the events
because UCSI_ENABLE_NTFY_CONNECTOR_CHANGE is not set in the ntfy mask.

Fixes: bdc62f2bae8f ("usb: typec: ucsi: Simplified registration and I/O API")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217106
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
- Delay setting ucsi->ntfy in ucsi_init() instead of adding a NULL pointer
  check to ucsi_connector_change()

Changes in v3:
- Add Link tag to commitmsg
---
 drivers/usb/typec/ucsi/ucsi.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index f632350f6dcb..0623861c597b 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1329,7 +1329,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 static int ucsi_init(struct ucsi *ucsi)
 {
 	struct ucsi_connector *con;
-	u64 command;
+	u64 command, ntfy;
 	int ret;
 	int i;
 
@@ -1341,8 +1341,8 @@ static int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable basic notifications */
-	ucsi->ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
-	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
+	ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ntfy;
 	ret = ucsi_send_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_reset;
@@ -1374,12 +1374,13 @@ static int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable all notifications */
-	ucsi->ntfy = UCSI_ENABLE_NTFY_ALL;
-	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
+	ntfy = UCSI_ENABLE_NTFY_ALL;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ntfy;
 	ret = ucsi_send_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_unregister;
 
+	ucsi->ntfy = ntfy;
 	return 0;
 
 err_unregister:
-- 
2.39.1