linux-yocto/net/sched
Pedro Tammela 2f2190ce4c net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
commit ac9fe7dd8e730a103ae4481147395cc73492d786 upstream.

Savino says:
    "We are writing to report that this recent patch
    (141d34391abbb315d68556b7c67ad97885407547) [1]
    can be bypassed, and a UAF can still occur when HFSC is utilized with
    NETEM.

    The patch only checks the cl->cl_nactive field to determine whether
    it is the first insertion or not [2], but this field is only
    incremented by init_vf [3].

    By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the
    check and insert the class twice in the eltree.
    Under normal conditions, this would lead to an infinite loop in
    hfsc_dequeue for the reasons we already explained in this report [5].

    However, if TBF is added as root qdisc and it is configured with a
    very low rate,
    it can be utilized to prevent packets from being dequeued.
    This behavior can be exploited to perform subsequent insertions in the
    HFSC eltree and cause a UAF."

To fix both the UAF and the infinite loop, with netem as an hfsc child,
check explicitly in hfsc_enqueue whether the class is already in the eltree
whenever the HFSC_RSC flag is set.

[1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547
[2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572
[3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677
[4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574
[5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u

Fixes: 37d9cf1a3c ("sched: Fix detection of empty queues in child qdiscs")
Reported-by: Savino Dicanosa <savy@syst3mfailure.io>
Reported-by: William Liu <will@willsroot.io>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Link: https://patch.msgid.link/20250522181448.1439717-2-pctammela@mojatatu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04 14:43:51 +02:00
..
act_api.c net/sched: act_api: deny mismatched skip_sw/skip_hw flags for actions created by classifiers 2024-10-23 11:31:27 +02:00
act_bpf.c net: Rename mono_delivery_time to tstamp_type for scalabilty 2024-05-23 14:14:23 -07:00
act_connmark.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_csum.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_ct.c sched: act_ct: avoid -Wflex-array-member-not-at-end warning 2024-08-12 17:54:24 -07:00
act_ctinfo.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_gact.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_gate.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_ife.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_meta_mark.c
act_meta_skbprio.c
act_meta_skbtcindex.c
act_mirred.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-02-22 15:29:26 -08:00
act_mpls.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_nat.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_pedit.c net: sched: Annotate struct tc_pedit with __counted_by 2024-02-19 10:58:24 +00:00
act_police.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_sample.c net: sched: act_sample: add action cookie to sample 2024-07-05 17:45:47 -07:00
act_simple.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_skbedit.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
act_skbmod.c net/sched: act_skbmod: convert comma to semicolon 2024-07-11 17:12:15 -07:00
act_tunnel_key.c net: fix geneve_opt length integer overflow 2025-04-10 14:39:34 +02:00
act_vlan.c tc: adjust network header after 2nd vlan push 2024-08-27 11:37:42 +02:00
cls_api.c tc: Ensure we have enough buffer space when sending filter netlink notifications 2025-04-20 10:15:07 +02:00
cls_basic.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_bpf.c net: sched: refine software bypass handling in tc_run 2025-02-08 09:57:25 +01:00
cls_cgroup.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_flow.c net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute 2025-01-17 13:40:37 +01:00
cls_flower.c net: fix geneve_opt length integer overflow 2025-04-10 14:39:34 +02:00
cls_fw.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_matchall.c net: sched: refine software bypass handling in tc_run 2025-02-08 09:57:25 +01:00
cls_route.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
cls_u32.c net: sched: refine software bypass handling in tc_run 2025-02-08 09:57:25 +01:00
em_canid.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_cmp.c move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
em_ipset.c
em_ipt.c
em_meta.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_nbyte.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_text.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
em_u32.c net: fill in MODULE_DESCRIPTION()s for net/sched 2024-02-09 14:12:02 -08:00
ematch.c net_sched: reject TCF_EM_SIMPLE case for complex ematch module 2022-12-19 09:43:18 +00:00
Kconfig net: sched: Remove NET_ACT_IPT from Kconfig 2024-02-13 11:24:35 +01:00
Makefile net/sched: Retire ipt action 2024-01-02 12:41:16 +00:00
sch_api.c net_sched: Prevent creation of classes with TC_H_ROOT 2025-03-22 12:54:13 -07:00
sch_blackhole.c
sch_cake.c sched: sch_cake: add bounds checks to host bulk flow fairness counts 2025-01-17 13:40:41 +01:00
sch_cbs.c net/sched: cbs: Fix integer overflow in cbs_set_port_rate() 2024-12-14 20:03:47 +01:00
sch_choke.c net: sched: fix ordering of qlen adjustment 2024-12-27 14:01:57 +01:00
sch_codel.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_drr.c sch_drr: make drr_qlen_notify() idempotent 2025-05-09 09:50:50 +02:00
sch_etf.c net_sched: sch_tfs: implement lockless etf_dump() 2024-04-19 11:34:07 +01:00
sch_ets.c sch_ets: make est_qlen_notify() idempotent 2025-05-09 09:50:51 +02:00
sch_fifo.c pfifo_tail_enqueue: Drop new packet when sch->limit == 0 2025-02-17 10:05:01 +01:00
sch_fq_codel.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_fq_pie.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_fq.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_frag.c net: dst: remove unnecessary input parameter in dst_alloc and dst_init 2023-09-12 11:42:25 +02:00
sch_generic.c ptr_ring: do not block hard interrupts in ptr_ring_resize_multiple() 2025-02-08 09:57:07 +01:00
sch_gred.c sched: address a potential NULL pointer dereference in the GRED scheduler. 2025-03-22 12:54:10 -07:00
sch_hfsc.c net_sched: hfsc: Address reentrant enqueue adding class to eltree twice 2025-06-04 14:43:51 +02:00
sch_hhf.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_htb.c sch_htb: make htb_deactivate() idempotent 2025-05-18 08:24:47 +02:00
sch_ingress.c bpf: Fix too early release of tcx_entry 2024-07-08 14:07:31 -07:00
sch_mq.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_mqprio_lib.c net: sched: Fill in missing MODULE_DESCRIPTION for qdiscs 2023-11-01 21:49:09 -07:00
sch_mqprio_lib.h net/sched: mqprio: allow per-TC user input of FP adminStatus 2023-04-13 22:22:10 -07:00
sch_mqprio.c netlink: introduce type-checking attribute iteration 2024-03-29 15:06:02 -07:00
sch_multiq.c net: sched: sch_multiq: fix possible OOB write in multiq_tune() 2024-06-05 10:50:19 +01:00
sch_netem.c netem: Update sch->q.qlen before qdisc_tree_reduce_backlog() 2025-02-17 10:05:01 +01:00
sch_pie.c net_sched: Flush gso_skb list too during ->change() 2025-05-22 14:29:39 +02:00
sch_plug.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
sch_prio.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
sch_qfq.c sch_qfq: make qfq_qlen_notify() idempotent 2025-05-09 09:50:50 +02:00
sch_red.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
sch_sfb.c net/sched: Add module aliases for cls_,sch_,act_ modules 2024-02-02 10:57:55 -08:00
sch_sfq.c net_sched: sch_sfq: move the limit validation 2025-04-20 10:15:08 +02:00
sch_skbprio.c net_sched: skbprio: Remove overly strict queue assertions 2025-04-10 14:39:33 +02:00
sch_taprio.c net: sched: use RCU read-side critical section in taprio_dump() 2024-10-23 13:26:15 +02:00
sch_tbf.c net/sched: tbf: correct backlog statistic for GSO packets 2024-12-14 20:03:03 +01:00
sch_teql.c net: annotate writes on dev->mtu from ndo_change_mtu() 2024-05-07 16:19:14 -07:00