From: Johan Hovold <johan@kernel.org>
Date: Wed, 10 May 2017 16:18:27 +0000 (+0200)
Subject: USB: hub: fix SS hub-descriptor handling
X-Git-Tag: MMI-PSA29.97-13-9~5558^2~14
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2c25a2c818023df64463aac3288a9f969491e507;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

USB: hub: fix SS hub-descriptor handling

A SuperSpeed hub descriptor does not have any variable-length fields so
bail out when reading a short descriptor.

This avoids parsing and leaking two bytes of uninitialised slab data
through sysfs removable-attributes.

Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
Cc: stable <stable@vger.kernel.org>     # 2.6.39
Cc: John Youn <John.Youn@synopsys.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9dca59ef18b3..3ff1e9f89f2d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -380,8 +380,12 @@ static int get_hub_descriptor(struct usb_device *hdev, void *data)
 			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
 			dtype << 8, 0, data, size,
 			USB_CTRL_GET_TIMEOUT);
-		if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2))
+		if (hub_is_superspeed(hdev)) {
+			if (ret == size)
+				return ret;
+		} else if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2)) {
 			return ret;
+		}
 	}
 	return -EINVAL;
 }
@@ -1321,7 +1325,7 @@ static int hub_configure(struct usb_hub *hub,
 
 	/* Request the entire hub descriptor.
 	 * hub->descriptor can handle USB_MAXCHILDREN ports,
-	 * but the hub can/will return fewer bytes here.
+	 * but a (non-SS) hub can/will return fewer bytes here.
 	 */
 	ret = get_hub_descriptor(hdev, hub->descriptor);
 	if (ret < 0) {