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: ---truncated---

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

https://git.kernel.org/stable/c/093af62c023537f097d2ebdfaa0bc7c1a6e874e1

https://git.kernel.org/stable/c/28ddc1e0b898291323b62d770b1b931de131a528

https://git.kernel.org/stable/c/44481b244fcaa2b895a53081d6204c574720c38c

https://git.kernel.org/stable/c/ca0c4cc1d215dc22ab0e738c9f017c650f3183f5

https://git.kernel.org/stable/c/cd0e2bf7fb22fe9b989c59c42dca06367fd10e6b

https://git.kernel.org/stable/c/dac501397b9d81e4782232c39f94f4307b137452

https://git.kernel.org/stable/c/f7b2c7d9831af99369fe8ad9b2a68d78942f414e

https://git.kernel.org/stable/c/fd72ac9556a473fc7daf54efb6ca8a97180d621d

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_conne

Linux https://git.kernel.org/stable/c/093af62c023537f097d2ebdfaa0bc7c1a6e874e1 [No types assigned]

Linux https://git.kernel.org/stable/c/28ddc1e0b898291323b62d770b1b931de131a528 [No types assigned]

Linux https://git.kernel.org/stable/c/44481b244fcaa2b895a53081d6204c574720c38c [No types assigned]

Linux https://git.kernel.org/stable/c/ca0c4cc1d215dc22ab0e738c9f017c650f3183f5 [No types assigned]

Linux https://git.kernel.org/stable/c/cd0e2bf7fb22fe9b989c59c42dca06367fd10e6b [No types assigned]

Linux https://git.kernel.org/stable/c/dac501397b9d81e4782232c39f94f4307b137452 [No types assigned]

Linux https://git.kernel.org/stable/c/f7b2c7d9831af99369fe8ad9b2a68d78942f414e [No types assigned]

Linux https://git.kernel.org/stable/c/fd72ac9556a473fc7daf54efb6ca8a97180d621d [No types assigned]