Bugzilla – Bug 1224561
VUL-0: CVE-2024-35985: kernel: sched/eevdf: Prevent vlag from going out of bounds in reweight_eevdf()
Last modified: 2024-06-07 12:11:51 UTC
In the Linux kernel, the following vulnerability has been resolved: sched/eevdf: Prevent vlag from going out of bounds in reweight_eevdf() It was possible to have pick_eevdf() return NULL, which then causes a NULL-deref. This turned out to be due to entity_eligible() returning falsely negative because of a s64 multiplcation overflow. Specifically, reweight_eevdf() computes the vlag without considering the limit placed upon vlag as update_entity_lag() does, and then the scaling multiplication (remember that weight is 20bit fixed point) can overflow. This then leads to the new vruntime being weird which then causes the above entity_eligible() to go side-ways and claim nothing is eligible. Thus limit the range of vlag accordingly. All this was quite rare, but fatal when it does happen. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-35985 https://www.cve.org/CVERecord?id=CVE-2024-35985 https://git.kernel.org/stable/c/06f27e6d7bf0abf54488259ef36bbf0e1fccb35c https://git.kernel.org/stable/c/1560d1f6eb6b398bddd80c16676776c0325fe5fe https://git.kernel.org/stable/c/470d347b14b0ecffa9b39cf8f644fa2351db3efb https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-35985.mbox
All done, closing.