CVE-2024-38580 Information

Description

In the Linux kernel the following vulnerability has been resolved:

epoll: be better about file lifetimes

epoll can call out to vfs_poll() with a file pointer that may race with the last ‘fput()’. That would make f_count go down to zero and while the ep->mtx locking means that the resulting file pointer tear-down will be blocked until the poll returns it means that f_count is already dead and any use of it won’t actually get a reference to the file any more: it’s dead regardless.

Make sure we have a valid ref on the file pointer before we call down to vfs_poll() from the epoll routines.

Reference

https://git.kernel.org/stable/c/cbfd1088e24ec4c1199756a37cb8e4cd0a4b016e https://git.kernel.org/stable/c/559214eb4e5c3d05e69428af2fae2691ba1eb784 https://git.kernel.org/stable/c/4f65f4defe4e23659275ce5153541cd4f76ce2d2 https://git.kernel.org/stable/c/16e3182f6322575eb7c12e728ad3c7986a189d5d https://git.kernel.org/stable/c/4efaa5acf0a1d2b5947f98abb3acf8bfd966422b