CVE-2024-53057

A flaw was found in the packet scheduler API in the Linux kernel. An invalid assumption about qdiscs with major handle ffff allows qdiscs, such as DRR, that maintain an active class list to cause a use-after-free with a dangling class pointer.

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(-)

Ziming Zhang discovered that the DRM driver for VMware Virtual GPU did not properly handle certain error conditions, leading to a NULL pointer dereference. A local attacker could possibly trigger this vulnerability to cause a denial of service. Ye Zhang and Nicolas Wu discovered that the io_uring subsystem in the Linux kernel did not properly handle locking for rings with IOPOLL, leading to a double-free vulnerability. A local attacker could use this to cause a denial of service or possibly execute arbitrary code.