概要

In the Linux kernel, the following vulnerability has been resolved:sch/netem: fix use after free in netem_dequeueIf netem_dequeue() enqueues packet to inner qdisc and that qdiscreturns __NET_XMIT_STOLEN. The packet is dropped butqdisc_tree_reduce_backlog() is not called to update the parent sq.qlen, leading to the similar use-after-free as Commite04991a48dbaf382 ( netem: fix return value if duplicate enqueuefails )Commands to trigger KASAN UaF:ip link add type dummyip link set lo upip link set dummy0 uptc qdisc add dev lo parent root handle 1: drrtc filter add dev lo parent 1: basic classid 1:1tc class add dev lo classid 1:1 drrtc qdisc add dev lo parent 1:1 handle 2: netemtc qdisc add dev lo parent 2: handle 3: drrtc filter add dev lo parent 3: basic classid 3:1 action mirred egressredirect dev dummy0tc class add dev lo classid 3:1 drrping -c1 -W0.01 localhost # Trigger bugtc class del dev lo classid 1:1tc class add dev lo classid 1:1 drrping -c1 -W0.01 localhost # UaF

CVSS v3 指标

安全公告

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