linux/drivers/thunderbolt/acpi.c
Mario Limonciello 4d395c5e74 thunderbolt: Fix possible NULL pointer dereference in tb_acpi_add_link()
When we walk up the device hierarchy in tb_acpi_add_link() make sure we
break the loop if the device has no parent. Otherwise we may crash the
kernel by dereferencing a NULL pointer.

Fixes: b2be2b05cf ("thunderbolt: Create device links from ACPI description")
Cc: stable@vger.kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2021-01-28 15:30:57 +03:00

118 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* ACPI support
*
* Copyright (C) 2020, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*/
#include <linux/acpi.h>
#include "tb.h"
static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
void **return_value)
{
struct fwnode_reference_args args;
struct fwnode_handle *fwnode;
struct tb_nhi *nhi = data;
struct acpi_device *adev;
struct pci_dev *pdev;
struct device *dev;
int ret;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
fwnode = acpi_fwnode_handle(adev);
ret = fwnode_property_get_reference_args(fwnode, "usb4-host-interface",
NULL, 0, 0, &args);
if (ret)
return AE_OK;
/* It needs to reference this NHI */
if (nhi->pdev->dev.fwnode != args.fwnode)
goto out_put;
/*
* Try to find physical device walking upwards to the hierarcy.
* We need to do this because the xHCI driver might not yet be
* bound so the USB3 SuperSpeed ports are not yet created.
*/
dev = acpi_get_first_physical_node(adev);
while (!dev) {
adev = adev->parent;
if (!adev)
break;
dev = acpi_get_first_physical_node(adev);
}
if (!dev)
goto out_put;
/*
* Check that the device is PCIe. This is because USB3
* SuperSpeed ports have this property and they are not power
* managed with the xHCI and the SuperSpeed hub so we create the
* link from xHCI instead.
*/
while (dev && !dev_is_pci(dev))
dev = dev->parent;
if (!dev)
goto out_put;
/*
* Check that this actually matches the type of device we
* expect. It should either be xHCI or PCIe root/downstream
* port.
*/
pdev = to_pci_dev(dev);
if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI ||
(pci_is_pcie(pdev) &&
(pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) {
const struct device_link *link;
link = device_link_add(&pdev->dev, &nhi->pdev->dev,
DL_FLAG_AUTOREMOVE_SUPPLIER |
DL_FLAG_PM_RUNTIME);
if (link) {
dev_dbg(&nhi->pdev->dev, "created link from %s\n",
dev_name(&pdev->dev));
} else {
dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n",
dev_name(&pdev->dev));
}
}
out_put:
fwnode_handle_put(args.fwnode);
return AE_OK;
}
/**
* tb_acpi_add_links() - Add device links based on ACPI description
* @nhi: Pointer to NHI
*
* Goes over ACPI namespace finding tunneled ports that reference to
* @nhi ACPI node. For each reference a device link is added. The link
* is automatically removed by the driver core.
*/
void tb_acpi_add_links(struct tb_nhi *nhi)
{
acpi_status status;
if (!has_acpi_companion(&nhi->pdev->dev))
return;
/*
* Find all devices that have usb4-host-controller interface
* property that references to this NHI.
*/
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 32,
tb_acpi_add_link, NULL, nhi, NULL);
if (ACPI_FAILURE(status))
dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
}