patch "USB: hub: fix SS hub-descriptor handling" added to usb-linus

patch "USB: hub: fix SS hub-descriptor handling" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: hub: fix SS hub-descriptor handling

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 2c25a2c818023df64463aac3288a9f969491e507 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 10 May 2017 18:18:27 +0200
Subject: 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>
---
 drivers/usb/core/hub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

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) {
-- 
2.13.0