CVE-2022-50220
Description
In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix linkwatch use-after-free on disconnect usbnet uses the work usbnet_deferred_kevent() to perform tasks which may sleep. On disconnect, completion of the work was originally awaited in ->ndo_stop(). But in 2003, that was moved to ->disconnect() by historic commit "[PATCH] USB: usbnet, prevent exotic rtnl deadlock": https://git.kernel.org/tglx/history/c/0f138bbfd83c The change was made because back then, the kernel's workqueue implementation did not allow waiting for a single work. One had to wait for completion of *all* work by calling flush_scheduled_work(), and that could deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex held in ->ndo_stop(). The commit solved one problem but created another: It causes a use-after-free in USB Ethernet drivers aqc111.c, asix_devices.c, ax88179_178a.c, ch9200.c and smsc75xx.c: * If the drivers receive a link change interrupt immediately before disconnect, they raise EVENT_LINK_RESET in their (non-sleepable) ->status() callback and schedule usbnet_deferred_kevent(). * usbnet_deferred_kevent() invokes the driver's ->link_reset() callback, which calls netif_carrier_{on,off}(). * That in turn schedules the work linkwatch_event(). Because usbnet_deferred_kevent() is awaited after unregister_netdev(), netif_carrier_{on,off}() may operate on an unregistered netdev and linkwatch_event() may run after free_netdev(), causing a use-after-free. In 2010, usbnet was changed to only wait for a single instance of usbnet_deferred_kevent() instead of *all* work by commit 23f333a2bfaf ("drivers/net: don't use flush_scheduled_work()"). Unfortunately the commit neglected to move the wait back to ->ndo_stop(). Rectify that omission at long last.
CVSS Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Threat Intelligence
Weaknesses 1
Affected Products 8
| Vendor | Product | Version | Range |
|---|---|---|---|
| linux | linux_kernel | * | ≥2.6.38 – <4.9.326 |
| linux | linux_kernel | * | ≥4.10 – <4.14.291 |
| linux | linux_kernel | * | ≥4.15 – <4.19.256 |
| linux | linux_kernel | * | ≥4.20 – <5.4.211 |
| linux | linux_kernel | * | ≥5.5 – <5.10.137 |
| linux | linux_kernel | * | ≥5.11 – <5.15.61 |
| linux | linux_kernel | * | ≥5.16 – <5.18.18 |
| linux | linux_kernel | * | ≥5.19 – <5.19.2 |
References 9
- git.kernel.org https://git.kernel.org/stable/c/135199a2edd459d2b123144efcd7f9bcd95128e4
- git.kernel.org https://git.kernel.org/stable/c/635fd8953e4309b54ca6a81bed1d4a87668694f4
- git.kernel.org https://git.kernel.org/stable/c/7f77dcbc030c2faa6d8e8a594985eeb34018409e
- git.kernel.org https://git.kernel.org/stable/c/8b4588b8b00b299be16a35be67b331d8fdba03f3
- git.kernel.org https://git.kernel.org/stable/c/a69e617e533edddf3fa3123149900f36e0a6dc74
- git.kernel.org https://git.kernel.org/stable/c/d2d6b530d89b0a912148018027386aa049f0a309
- git.kernel.org https://git.kernel.org/stable/c/d49bb8cf9bfaa06aa527eb30f1a52a071da2e32f
- git.kernel.org https://git.kernel.org/stable/c/db3b738ae5f726204876f4303c49cfdf4311403f
- git.kernel.org https://git.kernel.org/stable/c/e2a521a7dcc463c5017b4426ca0804e151faeff7
Remediation
- git.kernel.org https://git.kernel.org/stable/c/135199a2edd459d2b123144efcd7f9bcd95128e4
- git.kernel.org https://git.kernel.org/stable/c/635fd8953e4309b54ca6a81bed1d4a87668694f4
- git.kernel.org https://git.kernel.org/stable/c/7f77dcbc030c2faa6d8e8a594985eeb34018409e
- git.kernel.org https://git.kernel.org/stable/c/8b4588b8b00b299be16a35be67b331d8fdba03f3
- git.kernel.org https://git.kernel.org/stable/c/a69e617e533edddf3fa3123149900f36e0a6dc74
- git.kernel.org https://git.kernel.org/stable/c/d2d6b530d89b0a912148018027386aa049f0a309
- git.kernel.org https://git.kernel.org/stable/c/d49bb8cf9bfaa06aa527eb30f1a52a071da2e32f
- git.kernel.org https://git.kernel.org/stable/c/db3b738ae5f726204876f4303c49cfdf4311403f
- git.kernel.org https://git.kernel.org/stable/c/e2a521a7dcc463c5017b4426ca0804e151faeff7