CVE-2024-57986

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

HID: core: Fix assumption that Resolution Multipliers must be in Logical Collections

A report in 2019 by the syzbot fuzzer was found to be connected to two errors in the HID core associated with Resolution Multipliers. One of the errors was fixed by commit ea427a222d8b ("HID: core: Fix deadloop in hid_apply_multiplier."), but the other has not been fixed.

This error arises because hid_apply_multipler() assumes that every Resolution Multiplier control is contained in a Logical Collection, i.e., there's no way the routine can ever set multiplier_collection to NULL. This is in spite of the fact that the function starts with a big comment saying:

 * "The Resolution Multiplier control must be contained in the same
 * Logical Collection as the control(s) to which it is to be applied.
   ...
 *  If no Logical Collection is
 * defined, the Resolution Multiplier is associated with all
 * controls in the report."
 * HID Usage Table, v1.12, Section 4.3.1, p30
 *
 * Thus, search from the current collection upwards until we find a
 * logical collection...

The comment and the code overlook the possibility that none of the collections found may be a Logical Collection.

The fix is to set the multiplier_collection pointer to NULL if the collection found isn't a Logical Collection.

This vulnerability is rated as Moderate impact by Red Hat Product Security because triggering it requires local access or the ability to attach a physical or virtual Human Interface Device (HID). An attacker must supply a malformed HID report descriptor to induce a kernel crash during descriptor processing, resulting in a denial of service. The issue does not compromise data confidentiality or system integrity, and standard environments restricting physical access and privileged local interfaces have reduced exposure.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.