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| author | Jamal Hadi Salim <jhs@mojatatu.com> | 2026-09-01 17:39:23 -0400 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-09-05 13:47:29 -0700 |
| commit | 4864f58c53eb47257d55e01f47d4a9f355f7f970 (patch) | |
| tree | c4b30c24397d715b5092c15beae1f3b6727735dc /scripts/basic/split-include.c | |
| parent | 094cc07f98dfe70a34e2a1923af17fd29b8cf622 (diff) | |
| download | linux-4864f58c53eb47257d55e01f47d4a9f355f7f970.tar.gz linux-4864f58c53eb47257d55e01f47d4a9f355f7f970.zip | |
net/sched: fq_pie: clamp quantum in change path
fq_pie_change() accepts any quantum value from userspace, including 1.
With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1
makes the deficit-refill loop spin ~2^31 times under the qdisc lock
(a soft lockup / denial of service).
Add max(256U, ...) matching fq_codel_change().
Conditions to recreate the bug:
CONFIG_NET_SCH_FQ_PIE=y. Requires CAP_NET_ADMIN (namespace-local via
unshare -Urn suffices).
tc qdisc add dev dummy0 root fq_pie
tc qdisc change dev dummy0 root fq_pie quantum 1 stab data 32768 size_log 15 cell_log 0
Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler")
Reported-by: Vega <vega@nebusec.ai>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/QDISC-0CFC.v3.20260901204856@mojatatu.com.3
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'scripts/basic/split-include.c')
0 files changed, 0 insertions, 0 deletions