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

patch "USB: hub: fix non-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 non-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 bec444cd1c94c48df409a35ad4e5b143c245c3f7 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 10 May 2017 18:18:28 +0200
Subject: USB: hub: fix non-SS hub-descriptor handling

Add missing sanity check on the non-SuperSpeed hub-descriptor length in
order to avoid parsing and leaking two bytes of uninitialised slab data
through sysfs removable-attributes (or a compound-device debug
statement).

Note that we only make sure that the DeviceRemovable field is always
present (and specifically ignore the unused PortPwrCtrlMask field) in
order to continue support any hubs with non-compliant descriptors. As a
further safeguard, the descriptor buffer is also cleared.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/core/hub.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3ff1e9f89f2d..f77a4ebde7d5 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -362,7 +362,8 @@ static void usb_set_lpm_parameters(struct usb_device *udev)
 }
 
 /* USB 2.0 spec Section 11.24.4.5 */
-static int get_hub_descriptor(struct usb_device *hdev, void *data)
+static int get_hub_descriptor(struct usb_device *hdev,
+		struct usb_hub_descriptor *desc)
 {
 	int i, ret, size;
 	unsigned dtype;
@@ -378,12 +379,16 @@ static int get_hub_descriptor(struct usb_device *hdev, void *data)
 	for (i = 0; i < 3; i++) {
 		ret = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
 			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
-			dtype << 8, 0, data, size,
+			dtype << 8, 0, desc, size,
 			USB_CTRL_GET_TIMEOUT);
 		if (hub_is_superspeed(hdev)) {
 			if (ret == size)
 				return ret;
-		} else if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2)) {
+		} else if (ret >= USB_DT_HUB_NONVAR_SIZE + 2) {
+			/* Make sure we have the DeviceRemovable field. */
+			size = USB_DT_HUB_NONVAR_SIZE + desc->bNbrPorts / 8 + 1;
+			if (ret < size)
+				return -EMSGSIZE;
 			return ret;
 		}
 	}
@@ -1317,7 +1322,7 @@ static int hub_configure(struct usb_hub *hub,
 	}
 	mutex_init(&hub->status_mutex);
 
-	hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
+	hub->descriptor = kzalloc(sizeof(*hub->descriptor), GFP_KERNEL);
 	if (!hub->descriptor) {
 		ret = -ENOMEM;
 		goto fail;
-- 
2.13.0