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| author | Jamal Hadi Salim <jhs@mojatatu.com> | 2026-09-01 17:39:25 -0400 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-09-05 13:47:30 -0700 |
| commit | eb56a495f59baf6cad5ed80e3ffb9078098b1346 (patch) | |
| tree | aa7293245bce13a09f7a72e0b4aef9a78e625a51 /scripts/basic/split-include.c | |
| parent | fb9f88a33c516ea5c0bcd9a22ca288b246b34567 (diff) | |
| download | linux-eb56a495f59baf6cad5ed80e3ffb9078098b1346.tar.gz linux-eb56a495f59baf6cad5ed80e3ffb9078098b1346.zip | |
net/sched: hhf: clamp quantum in change and init paths
hhf_change() accepts any quantum 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, ...) in hhf_change() matching fq_codel_change(). Clamp
hhf_init() to [256, 1<<20] matching the siblings, and remove the old
fallback that only set quantum=256 on overflow.
Conditions to recreate the bug:
CONFIG_NET_SCH_HHF=y. Requires CAP_NET_ADMIN (namespace-local via
unshare -Urn suffices).
tc qdisc add dev dummy0 root hhf
tc qdisc change dev dummy0 root hhf quantum 1 stab data 32768 size_log 15 cell_log 0
Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
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.5
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'scripts/basic/split-include.c')
0 files changed, 0 insertions, 0 deletions