CVE-2024-40913

A vulnerability was found in the Linux kernel's cachefiles component, regarding the handling of anonymous file descriptors. This issue occurs when an anonymous fd is exposed to userland before confirming the success of the copy_to_user() operation, which can lead to a use-after-free condition.

In the Linux kernel, the following vulnerability has been resolved: cachefiles: defer exposing anon_fd until after copy_to_user() succeeds After installing the anonymous fd, we can now see it in userland and close it. However, at this point we may not have gotten the reference count of the cache, but we will put it during colse fd, so this may cause a cache UAF. So grab the cache reference count before fd_install(). In addition, by kernel convention, fd is taken over by the user land after fd_install(), and the kernel should not call close_fd() after that, i.e., it should call fd_install() after everything is ready, thus fd_install() is called after copy_to_user() succeeds.

Chenyuan Yang discovered that the CEC driver driver in the Linux kernel contained a use-after-free vulnerability. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. It was discovered that the JFS file system contained an out-of-bounds read vulnerability when printing xattr debug information. A local attacker could use this to cause a denial of service.