CVE-2024-50273

/// Technical description

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

btrfs: reinitialize delayed ref list after deleting it from the list

At insert_delayed_ref() if we need to update the action of an existing

ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's

ref_add_list using list_del(), which leaves the ref's add_list member

not reinitialized, as list_del() sets the next and prev members of the

list to LIST_POISON1 and LIST_POISON2, respectively.

If later we end up calling drop_delayed_ref() against the ref, which can

happen during merging or when destroying delayed refs due to a transaction

abort, we can trigger a crash since at drop_delayed_ref() we call

list_empty() against the ref's add_list, which returns false since

the list was not reinitialized after the list_del() and as a consequence

we call list_del() again at drop_delayed_ref(). This results in an

invalid list access since the next and prev members are set to poison

pointers, resulting in a splat if C

/// 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