diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2018-05-14 11:57:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 07:42:56 -0800 |
| commit | 52f305530ab6e5915b5e5ee0cb9525df42f2b691 (patch) | |
| tree | 9239e8e65967d7c86aaabf82129b95ccdfd947ef /drivers/usb/host/xhci-hub.c | |
| parent | 97d34e8ea0719828c723e333d97918e9a4590cb2 (diff) | |
xhci: Fix USB3 NULL pointer dereference at logical disconnect.
[ Upstream commit 2278446e2b7cd33ad894b32e7eb63afc7db6c86e ]
Hub driver will try to disable a USB3 device twice at logical disconnect,
racing with xhci_free_dev() callback from the first port disable.
This can be triggered with "udisksctl power-off --block-device <disk>"
or by writing "1" to the "remove" sysfs file for a USB3 device
in 4.17-rc4.
USB3 devices don't have a similar disabled link state as USB2 devices,
and use a U3 suspended link state instead. In this state the port
is still enabled and connected.
hub_port_connect() first disconnects the device, then later it notices
that device is still enabled (due to U3 states) it will try to disable
the port again (set to U3).
The xhci_free_dev() called during device disable is async, so checking
for existing xhci->devs[i] when setting link state to U3 the second time
was successful, even if device was being freed.
The regression was caused by, and whole thing revealed by,
Commit 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device")
which sets xhci->devs[i]->udev to NULL before xhci_virt_dev() returned.
and causes a NULL pointer dereference the second time we try to set U3.
Fix this by checking xhci->devs[i]->udev exists before setting link state.
The original patch went to stable so this fix needs to be applied there as
well.
Fixes: 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device")
Cc: <stable@vger.kernel.org>
Reported-by: Jordan Glover <Golden_Miller83@protonmail.ch>
Tested-by: Jordan Glover <Golden_Miller83@protonmail.ch>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/usb/host/xhci-hub.c')
| -rw-r--r-- | drivers/usb/host/xhci-hub.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 45a03eff4db1..0f09ab5399f4 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -366,7 +366,7 @@ int xhci_find_slot_id_by_port(struct usb_hcd *hcd, struct xhci_hcd *xhci, slot_id = 0; for (i = 0; i < MAX_HC_SLOTS; i++) { - if (!xhci->devs[i]) + if (!xhci->devs[i] || !xhci->devs[i]->udev) continue; speed = xhci->devs[i]->udev->speed; if (((speed >= USB_SPEED_SUPER) == (hcd->speed >= HCD_USB3)) |