CVE-2024-43891

/// Technical description

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

tracing: Have format file honor EVENT_FILE_FL_FREED

When eventfs was introduced, special care had to be done to coordinate the

freeing of the file meta data with the files that are exposed to user

space. The file meta data would have a ref count that is set when the file

is created and would be decremented and freed after the last user that

opened the file closed it. When the file meta data was to be freed, it

would set a flag (EVENT_FILE_FL_FREED) to denote that the file is freed,

and any new references made (like new opens or reads) would fail as it is

marked freed. This allowed other meta data to be freed after this flag was

set (under the event_mutex).

All the files that were dynamically created in the events directory had a

pointer to the file meta data and would call event_release() when the last

reference to the user space file was closed. This would be the time that it

is safe to free the file meta data.

A

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References