[PATCH 3.13.y-ckt 025/121] usb: Do not allow usb_alloc_streams on unconfigured devices

From: Kamal Mostafa
Date: Tue Dec 02 2014 - 14:35:26 EST


3.13.11-ckt12 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@xxxxxxxxxx>

commit 90a646c770c50cc206ceba0d7b50453c46c13c36 upstream.

This commit fixes the following oops:

[10238.622067] scsi host3: uas_eh_bus_reset_handler start
[10240.766164] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10245.779365] usb 3-4: device descriptor read/8, error -110
[10245.883331] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10250.897603] usb 3-4: device descriptor read/8, error -110
[10251.058200] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
[10251.058244] IP: [<ffffffff815ac6e1>] xhci_check_streams_endpoint+0x91/0x140
<snip>
[10251.059473] Call Trace:
[10251.059487] [<ffffffff815aca6c>] xhci_calculate_streams_and_bitmask+0xbc/0x130
[10251.059520] [<ffffffff815aeb5f>] xhci_alloc_streams+0x10f/0x5a0
[10251.059548] [<ffffffff810a4685>] ? check_preempt_curr+0x75/0xa0
[10251.059575] [<ffffffff810a46dc>] ? ttwu_do_wakeup+0x2c/0x100
[10251.059601] [<ffffffff810a49e6>] ? ttwu_do_activate.constprop.111+0x66/0x70
[10251.059635] [<ffffffff815779ab>] usb_alloc_streams+0xab/0xf0
[10251.059662] [<ffffffffc0616b48>] uas_configure_endpoints+0x128/0x150 [uas]
[10251.059694] [<ffffffffc0616bac>] uas_post_reset+0x3c/0xb0 [uas]
[10251.059722] [<ffffffff815727d9>] usb_reset_device+0x1b9/0x2a0
[10251.059749] [<ffffffffc0616f42>] uas_eh_bus_reset_handler+0xb2/0x190 [uas]
[10251.059781] [<ffffffff81514293>] scsi_try_bus_reset+0x53/0x110
[10251.059808] [<ffffffff815163b7>] scsi_eh_bus_reset+0xf7/0x270
<snip>

The problem is the following call sequence (simplified):

1) usb_reset_device
2) usb_reset_and_verify_device
2) hub_port_init
3) hub_port_finish_reset
3) xhci_discover_or_reset_device
This frees xhci->devs[slot_id]->eps[ep_index].ring for all eps but 0
4) usb_get_device_descriptor
This fails
5) hub_port_init fails
6) usb_reset_and_verify_device fails, does not restore device config
7) uas_post_reset
8) xhci_alloc_streams
NULL deref on the free-ed ring

This commit fixes this by not allowing usb_alloc_streams to continue if
the device is not configured.

Note that we do allow usb_free_streams to continue after a (logical)
disconnect, as it is necessary to explicitly free the streams at the xhci
controller level.

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/usb/core/hcd.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index d39106c..4a4dae5 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2056,6 +2056,8 @@ int usb_alloc_streams(struct usb_interface *interface,
return -EINVAL;
if (dev->speed != USB_SPEED_SUPER)
return -EINVAL;
+ if (dev->state < USB_STATE_CONFIGURED)
+ return -ENODEV;

/* Streams only apply to bulk endpoints. */
for (i = 0; i < num_eps; i++)
--
1.9.1

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