In the Linux kernel, the following vulnerability has been resolved:
net/sched: sfq: clamp quantum in change path
sfq_change() accepts any non-negative quantum (only rejects
(int)ctl->quantum 1<<20
with -EINVAL, matching fq_codel_change() and the init clamp.
Conditions to recreate the bug:
CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via
unshare -Urn suffices).
tc qdisc add dev dummy0 root sfq
tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0
