CVE-2024-53057

In the Linux kernel, the following vulnerability has been resolved: net/sched: stop qdisc_tree_reduce_backlog on TC_H_ROOT In qdisc_tree_reduce_backlog, Qdiscs with major handle ffff: are assumed to be either root or ingress. This assumption is bogus since it's valid to create egress qdiscs with major handle ffff: Budimir Markovic found that for qdiscs like DRR that maintain an active class list, it will cause a UAF with a dangling class pointer. In 066a3b5b2346, the concern was to avoid iterating over the ingress qdisc since its parent is itself. The proper fix is to stop when parent TC_H_ROOT is reached because the only way to retrieve ingress is when a hierarchy which does not contain a ffff: major handle call into qdisc_lookup with TC_H_MAJ(TC_H_ROOT). In the scenario where major ffff: is an egress qdisc in any of the tree levels, the updates will also propagate to TC_H_ROOT, which then the iteration must stop. net/sched/sch_api.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

• linux linux kernel (>= 2.6.25 < 4.19.323) • linux linux kernel (>= 4.20 < 5.4.285) • linux linux kernel (>= 5.5 < 5.10.229) • linux linux kernel (>= 5.11 < 5.15.171) • linux linux kernel (>= 5.16 < 6.1.116) • linux linux kernel (>= 6.2 < 6.6.60) • linux linux kernel (>= 6.7 < 6.11.7) • linux linux kernel 6.12