Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: usbip: vudc: Fix use after free bug in vudc_remove due to race condition This patch follows up Zheng Wang's 2023 report of a use-after-free in vudc_remove(). The original thread stalled on Shuah Khan's request for runtime testing of the unplug/unbind path. This patch supplies that testing and keeps Zheng's original fix shape. In vudc_probe(), v_init_timer() binds udc->tr_timer.timer to v_timer(). usbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer(). vudc_remove() can then free the containing struct vudc while the timer is still pending or executing. KASAN confirms the race on an unpatched x86_64 QEMU guest with CONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop that repeatedly writes a socket fd to usbip_sockfd, closes the socket pair, and unbinds/rebinds usbip-vudc.0: BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0 Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239 Allocated by task 239: vudc_probe+0x4d/0xaa0 Freed by task 239: kfree+0x18f/0x520 device_release_driver_internal+0x388/0x540 unbind_store+0xd9/0x100 This lands in the timer core rather than v_timer() itself because the embedded timer_list is being walked after its containing struct vudc has already been freed. The underlying lifetime bug is the same one Zheng reported. With v_stop_timer() called from vudc_remove() and the timer deleted synchronously, the same harness completed 5000 bind/unbind iterations with no KASAN report.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected b6a0ca11186759ad7045d68a5447b1e89f658384 before 61704e5cf9cd7464b510eb606e7e2978b1160a64; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before dcc1c90b28b28b7c493547506297e78653f81952; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before 1036ac6148995feaf486014d32bf26bf993c06a9; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before a0638db2340ee053ab0450656a763fd111475e54; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before d07ed707467ce05ea9c03412d0c5ee9d0fe386a6; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before 88d459e5b5a46da1ef9fd6f52d9439343edeec88; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before 207bf80362df3fce8ebc9723351dcb1bc6d9ed0f; affected b6a0ca11186759ad7045d68a5447b1e89f658384 before d96209626a29ea64666be98c30b30ac82e5f1be6 |
| Linux / Linux | affected 4.7; unaffected 0 before 4.7; unaffected 5.10.259 through 5.10.*; unaffected 5.15.210 through 5.15.*; unaffected 6.1.176 through 6.1.*; unaffected 6.6.143 through 6.6.*; unaffected 6.12.93 through 6.12.*; unaffected 6.18.35 through 6.18.*; unaffected 7.0.12 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64
- https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952
- https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9
- https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54
- https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6
- https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88
- https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f
- https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6