CVE-2024-53057

Summary

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(-)

Impact & exploitability

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products we track (1)

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/05df1b1dff8f197f1c275b57ccb2ca33021df552 ↗

Additional information

• NVD record
• https://git.kernel.org/stable/c/05df1b1dff8f197f1c275b57ccb2ca33021df552Patch
• https://git.kernel.org/stable/c/2e95c4384438adeaa772caa560244b1a2efef816Patch
• https://git.kernel.org/stable/c/580b3189c1972aff0f993837567d36392e9d981bPatch
• https://git.kernel.org/stable/c/597cf9748c3477bf61bc35f0634129f56764ad24Patch
• https://git.kernel.org/stable/c/9995909615c3431a5304c1210face5f268d24dbaPatch
• https://git.kernel.org/stable/c/ce691c814bc7a3c30c220ffb5b7422715458fd9bPatch
• https://git.kernel.org/stable/c/dbe778b08b5101df9e89bc06e0a3a7ecd2f4ef20Patch
• https://git.kernel.org/stable/c/e7f9a6f97eb067599a74f3bcb6761976b0ed303ePatch