CVE-2024-40909 Information

Description

In the Linux kernel the following vulnerability has been resolved:

bpf: Fix a potential use-after-free in bpf_link_free()

After commit 1a80dbcb2dba bpf_link can be freed by link->ops->dealloc_deferred but the code still tests and uses link->ops->dealloc afterward which leads to a use-after-free as reported by syzbot. Actually one of them should be sufficient so just call one of them instead of both. Also add a WARN_ON() in case of any problematic implementation.

Reference

https://git.kernel.org/stable/c/91cff53136daeff50816b0baeafd38a6976f6209 https://git.kernel.org/stable/c/fa97b8fed9896f1e89cb657513e483a152d4c382 https://git.kernel.org/stable/c/2884dc7d08d98a89d8d65121524bb7533183a63a