Message-ID: <2024022921-CVE-2023-52478-c0a1@gregkh>
Date: Thu, 29 Feb 2024 06:43:21 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: gregkh@...nel.org
Subject: CVE-2023-52478: HID: logitech-hidpp: Fix kernel crash on receiver USB disconnect

From: gregkh@...nel.org

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

HID: logitech-hidpp: Fix kernel crash on receiver USB disconnect

hidpp_connect_event() has *four* time-of-check vs time-of-use (TOCTOU)
races when it races with itself.

hidpp_connect_event() primarily runs from a workqueue but it also runs
on probe() and if a "device-connected" packet is received by the hw
when the thread running hidpp_connect_event() from probe() is waiting on
the hw, then a second thread running hidpp_connect_event() will be
started from the workqueue.

This opens the following races (note the below code is simplified):

1. Retrieving + printing the protocol (harmless race):

	if (!hidpp->protocol_major) {
		hidpp_root_get_protocol_version()
		hidpp->protocol_major = response.rap.params[0];
	}

We can actually see this race hit in the dmesg in the abrt output
attached to rhbz#2227968:

[ 3064.624215] logitech-hidpp-device 0003:046D:4071.0049: HID++ 4.5 device connected.
[ 3064.658184] logitech-hidpp-device 0003:046D:4071.0049: HID++ 4.5 device connected.

Testing with extra logging added has shown that after this the 2 threads
take turn grabbing the hw access mutex (send_mutex) so they ping-pong
through all the other TOCTOU cases managing to hit all of them:

2. Updating the name to the HIDPP name (harmless race):

	if (hidpp->name == hdev->name) {
		...
		hidpp->name = new_name;
	}

3. Initializing the power_supply class for the battery (problematic!):

hidpp_initialize_battery()
{
        if (hidpp->battery.ps)
                return 0;

	probe_battery(); /* Blocks, threads take turns executing this */

	hidpp->battery.desc.properties =
		devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);

	hidpp->battery.ps =
		devm_power_supply_register(&hidpp->hid_dev->dev,
					   &hidpp->battery.desc, cfg);
}

4. Creating delayed input_device (potentially problematic):

	if (hidpp->delayed_input)
		return;

	hidpp->delayed_input = hidpp_allocate_input(hdev);

The really big problem here is 3. Hitting the race leads to the following
sequence:

	hidpp->battery.desc.properties =
		devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);

	hidpp->battery.ps =
		devm_power_supply_register(&hidpp->hid_dev->dev,
					   &hidpp->battery.desc, cfg);

	...

	hidpp->battery.desc.properties =
		devm_kmemdup(dev, hidpp_battery_props, cnt, GFP_KERNEL);

	hidpp->battery.ps =
		devm_power_supply_register(&hidpp->hid_dev->dev,
					   &hidpp->battery.desc, cfg);

So now we have registered 2 power supplies for the same battery,
which looks a bit weird from userspace's pov but this is not even
the really big problem.

Notice how:

1. This is all devm-maganaged
2. The hidpp->battery.desc struct is shared between the 2 power supplies
3. hidpp->battery.desc.properties points to the result from the second
   devm_kmemdup()

This causes a use after free scenario on USB disconnect of the receiver:
1. The last registered power supply class device gets unregistered
2. The memory from the last devm_kmemdup() call gets freed,
   hidpp->battery.desc.properties now points to freed memory
3. The first registered power supply class device gets unregistered,
   this involves sending a remove uevent to userspace which invokes
   power_supply_uevent() to fill the uevent data
4. power_supply_uevent() uses hidpp->battery.desc.properties which
   now points to freed memory leading to backtraces like this one:

Sep 22 20:01:35 eric kernel: BUG: unable to handle page fault for address: ffffb2140e017f08
..
Sep 22 20:01:35 eric kernel: Workqueue: usb_hub_wq hub_event
Sep 22 20:01:35 eric kernel: RIP: 0010:power_supply_uevent+0xee/0x1d0
..
Sep 22 20:01:35 eric kernel:  ? asm_exc_page_fault+0x26/0x30
Sep 22 20:01:35 eric kernel:  ? power_supply_uevent+0xee/0x1d0
Sep 22 20:01:35 eric kernel:  ? power_supply_uevent+0x10d/0x1d0
Sep 22 20:01:35 eric kernel:  dev_uevent+0x10f/0x2d0
Sep 22 20:01:35 eric kernel:  kobject_uevent_env+0x291/0x680
Sep 22 20:01:35 eric kernel:  power_supply_unregister+0x8e/0xa0
Sep 22 20:01:35 eric kernel:  release_nodes+0x3d/0xb0
Sep 22 20:01:35 eric kernel:  devres_release_group+0xfc/0x130
Sep 22 20:01:35 eric kernel:  hid_device_remove+0x56/0xa0
Sep 22 20:01:35 eric kernel:  device_release_driver_internal+0x19f/0x200
Sep 22 20:01:35 eric kernel:  bus_remove_device+0xc6/0x130
Sep 22 20:01:35 eric kernel:  device_del+0x15c/0x3f0
Sep 22 20:01:35 eric kernel:  ? __queue_work+0x1df/0x440
Sep 22 20:01:35 eric kernel:  hid_destroy_device+0x4b/0x60
Sep 22 20:01:35 eric kernel:  logi_dj_remove+0x9a/0x100 [hid_logitech_dj 5c91534a0ead2b65e04dd799a0437e3b99b21bc4]
Sep 22 20:01:35 eric kernel:  hid_device_remove+0x44/0xa0
Sep 22 20:01:35 eric kernel:  device_release_driver_internal+0x19f/0x200
Sep 22 20:01:35 eric kernel:  bus_remove_device+0xc6/0x130
Sep 22 20:01:35 eric kernel:  device_del+0x15c/0x3f0
Sep 22 20:01:35 eric kernel:  ? __queue_work+0x1df/0x440
Sep 22 20:01:35 eric kernel:  hid_destroy_device+0x4b/0x60
Sep 22 20:01:35 eric kernel:  usbhid_disconnect+0x47/0x60 [usbhid 727dcc1c0b94e6b4418727a468398ac3bca492f3]
Sep 22 20:01:35 eric kernel:  usb_unbind_interface+0x90/0x270
Sep 22 20:01:35 eric kernel:  device_release_driver_internal+0x19f/0x200
Sep 22 20:01:35 eric kernel:  bus_remove_device+0xc6/0x130
Sep 22 20:01:35 eric kernel:  device_del+0x15c/0x3f0
Sep 22 20:01:35 eric kernel:  ? kobject_put+0xa0/0x1d0
Sep 22 20:01:35 eric kernel:  usb_disable_device+0xcd/0x1e0
Sep 22 20:01:35 eric kernel:  usb_disconnect+0xde/0x2c0
Sep 22 20:01:35 eric kernel:  usb_disconnect+0xc3/0x2c0
Sep 22 20:01:35 eric kernel:  hub_event+0xe80/0x1c10

There have been quite a few bug reports (see Link tags) about this crash.

Fix all the TOCTOU issues, including the really bad power-supply related
system crash on USB disconnect, by making probe() use the workqueue for
running hidpp_connect_event() too, so that it can never run more then once.

The Linux kernel CVE team has assigned CVE-2023-52478 to this issue.


Affected and fixed versions
===========================

	Fixed in 4.14.328 with commit ca0c4cc1d215
	Fixed in 4.19.297 with commit 44481b244fca
	Fixed in 5.4.259 with commit cd0e2bf7fb22
	Fixed in 5.10.199 with commit 093af62c0235
	Fixed in 5.15.136 with commit 28ddc1e0b898
	Fixed in 6.1.59 with commit fd72ac9556a4
	Fixed in 6.5.8 with commit f7b2c7d9831a
	Fixed in 6.6 with commit dac501397b9d

Please see https://www.kernel.org or a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-52478
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/hid/hid-logitech-hidpp.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/ca0c4cc1d215dc22ab0e738c9f017c650f3183f5
	https://git.kernel.org/stable/c/44481b244fcaa2b895a53081d6204c574720c38c
	https://git.kernel.org/stable/c/cd0e2bf7fb22fe9b989c59c42dca06367fd10e6b
	https://git.kernel.org/stable/c/093af62c023537f097d2ebdfaa0bc7c1a6e874e1
	https://git.kernel.org/stable/c/28ddc1e0b898291323b62d770b1b931de131a528
	https://git.kernel.org/stable/c/fd72ac9556a473fc7daf54efb6ca8a97180d621d
	https://git.kernel.org/stable/c/f7b2c7d9831af99369fe8ad9b2a68d78942f414e
	https://git.kernel.org/stable/c/dac501397b9d81e4782232c39f94f4307b137452

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