CVE-2024-43830

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

leds: trigger: Unregister sysfs attributes before calling deactivate()

Triggers which have trigger specific sysfs attributes typically store related data in trigger-data allocated by the activate() callback and freed by the deactivate() callback.

Calling device_remove_groups() after calling deactivate() leaves a window where the sysfs attributes show/store functions could be called after deactivation and then operate on the just freed trigger-data.

Move the device_remove_groups() call to before deactivate() to close this race window.

This also makes the deactivation path properly do things in reverse order of the activation path which calls the activate() callback before calling device_add_groups().

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/0788a6f3523d3686a9eed5ea1e6fcce6841277b2
• https://git.kernel.org/stable/c/09c1583f0e10c918855d6e7540a79461a353e5d6
• https://git.kernel.org/stable/c/3fb6a9d67cfd812a547ac73ec02e1077c26c640d
• https://git.kernel.org/stable/c/734ba6437e80dfc780e9ee9d95f912392d12b5ea
• https://git.kernel.org/stable/c/c0dc9adf9474ecb7106e60e5472577375aedaed3
• https://git.kernel.org/stable/c/c3b7a650c8717aa89df318364609c86cbc040156
• https://git.kernel.org/stable/c/cb8aa9d2a4c8a15d6a43ccf901ef3d094aa60374
• https://git.kernel.org/stable/c/d1415125b701ef13370e2761f691ec632a5eb93a
• https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html