USB: hub: fix non-SS hub-descriptor handling

commit bec444cd1c94c48df409a35ad4e5b143c245c3f7 upstream.

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")
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>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3fe2609628eb86a3a0e0b4c8bca92afd1023a2a5..b627392ad52a1f9152b094be0420a5895d4a4e47 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -358,7 +358,8 @@ 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;
@@ -374,12 +375,16 @@ 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;
                }
        }
@@ -1299,7 +1304,7 @@ 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;