CVE Published: 19/11/2024 |
CVE Updated: 19/11/2024 |
CVE Year: 2024 Source: Linux |
Vendor: Linux |
Product: Linux Status : PUBLISHED
CVE-2024-53057 Description
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(-)