linux/net/sched
Al Viro 6d4c407744 net: sched: cls_u32: fix hnode refcounting
cls_u32.c misuses refcounts for struct tc_u_hnode - it counts references
via ->hlist and via ->tp_root together.  u32_destroy() drops the former
and, in case when there had been links, leaves the sucker on the list.
As the result, there's nothing to protect it from getting freed once links
are dropped.
That also makes the "is it busy" check incapable of catching the root
hnode - it *is* busy (there's a reference from tp), but we don't see it as
something separate.  "Is it our root?" check partially covers that, but
the problem exists for others' roots as well.

AFAICS, the minimal fix preserving the existing behaviour (where it doesn't
include oopsen, that is) would be this:
        * count tp->root and tp_c->hlist as separate references.  I.e.
have u32_init() set refcount to 2, not 1.
	* in u32_destroy() we always drop the former;
in u32_destroy_hnode() - the latter.

	That way we have *all* references contributing to refcount.  List
removal happens in u32_destroy_hnode() (called only when ->refcnt is 1)
an in u32_destroy() in case of tc_u_common going away, along with
everything reachable from it.  IOW, that way we know that
u32_destroy_key() won't free something still on the list (or pointed to by
someone's ->root).

Reproducer:

tc qdisc add dev eth0 ingress
tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: \
u32 divisor 1
tc filter add dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 801: offset at 0 mask 0f00 shift 6 \
plus 0 eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 200
tc filter change dev eth0 parent ffff: protocol ip prio 100 \
handle 1:0:11 u32 ht 1: link 0: offset at 0 mask 0f00 shift 6 plus 0 \
eat match ip protocol 6 ff
tc filter delete dev eth0 parent ffff: protocol ip prio 100

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-07 21:02:37 -07:00
..
act_api.c net: sched: null actions array pointer before releasing action 2018-09-03 21:47:33 -07:00
act_bpf.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_connmark.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_csum.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_gact.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_ife.c net: sched: action_ife: take reference to meta module 2018-09-04 12:20:21 -07:00
act_ipt.c net: sched: act_ipt: check for underflow in __tcf_ipt_init() 2018-10-01 22:34:14 -07:00
act_meta_mark.c net: remove duplicate includes 2017-12-13 13:18:46 -05:00
act_meta_skbprio.c net sched actions: change IFE modules alias names 2017-10-12 22:13:20 -07:00
act_meta_skbtcindex.c net: remove duplicate includes 2017-12-13 13:18:46 -05:00
act_mirred.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_nat.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_pedit.c net/sched: act_pedit: fix dump of extended layered op 2018-08-29 18:11:05 -07:00
act_police.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_sample.c net/sched: act_sample: fix NULL dereference in the data path 2018-09-14 08:46:28 -07:00
act_simple.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_skbedit.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_skbmod.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
act_tunnel_key.c net_sched: properly cancel netlink dump on failure 2018-09-07 23:05:07 -07:00
act_vlan.c net_sched: remove unnecessary ops->delete() 2018-08-21 12:45:44 -07:00
cls_api.c net_sched: notify filter deletion when deleting a chain 2018-09-13 09:07:40 -07:00
cls_basic.c sched: fix trailing whitespace 2018-07-24 14:10:42 -07:00
cls_bpf.c cls_bpf: Use kmemdup instead of duplicating it in cls_bpf_prog_from_ops 2018-07-29 13:19:49 -07:00
cls_cgroup.c net_sched: switch to rcu_work 2018-05-24 22:56:15 -04:00
cls_flow.c net_sched: switch to rcu_work 2018-05-24 22:56:15 -04:00
cls_flower.c net: sched: cls_flower: set correct offload data in fl_reoffload 2018-08-07 12:35:17 -07:00
cls_fw.c net_sched: switch to rcu_work 2018-05-24 22:56:15 -04:00
cls_matchall.c cls_matchall: fix tcf_unbind_filter missing 2018-08-16 12:08:26 -07:00
cls_route.c net_sched: switch to rcu_work 2018-05-24 22:56:15 -04:00
cls_rsvp6.c
cls_rsvp.c
cls_rsvp.h net_sched: switch to rcu_work 2018-05-24 22:56:15 -04:00
cls_tcindex.c net_sched: Fix missing res info when create new tc_index filter 2018-08-13 19:37:42 -07:00
cls_u32.c net: sched: cls_u32: fix hnode refcounting 2018-10-07 21:02:37 -07:00
em_canid.c
em_cmp.c
em_ipset.c netfilter: x_tables: move hook state into xt_action_param structure 2016-11-03 10:56:21 +01:00
em_ipt.c net: sched: add em_ipt ematch for calling xtables matches 2018-02-21 13:15:33 -05:00
em_meta.c net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
em_nbyte.c net: sched: em_nbyte: don't add the data offset twice 2018-01-24 14:52:40 -05:00
em_text.c net: Remove state argument from skb_find_text() 2015-02-22 15:59:54 -05:00
em_u32.c
ematch.c net: sched: ematch: obtain net pointer from blocks 2017-10-16 21:00:40 +01:00
Kconfig net/sched: add skbprio scheduler 2018-07-24 14:44:00 -07:00
Makefile net/sched: add skbprio scheduler 2018-07-24 14:44:00 -07:00
sch_api.c net: sched: Add policy validation for tc attributes 2018-10-05 14:26:44 -07:00
sch_atm.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_blackhole.c net_sched: blackhole: tell upper qdisc about dropped packets 2018-06-17 08:42:33 +09:00
sch_cake.c sch_cake: Fix TC filter flow override and expand it to hosts as well 2018-08-22 21:39:45 -07:00
sch_cbq.c net: sch: sch_cbq: add extack support 2017-12-21 12:32:51 -05:00
sch_cbs.c cbs: Add support for the graft function 2018-07-26 13:58:30 -07:00
sch_choke.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_codel.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_drr.c net: sch: sch_drr: add extack support 2017-12-21 12:32:51 -05:00
sch_dsmark.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_etf.c net/sched: Make etf report drops on error_queue 2018-07-04 22:30:28 +09:00
sch_fifo.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_fq_codel.c sch_fq_codel: zero q->flows_cnt when fq_codel_init fails 2018-07-12 12:32:09 -07:00
sch_fq.c net_sched: fq: take care of throttled flows before reuse 2018-05-02 16:37:38 -04:00
sch_generic.c net: remove bypassed check in sch_direct_xmit() 2018-05-31 13:26:19 -04:00
sch_gred.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_hfsc.c net_sched: remove a bogus warning in hfsc 2018-06-23 10:58:46 +09:00
sch_hhf.c treewide: kvzalloc() -> kvcalloc() 2018-06-12 16:19:22 -07:00
sch_htb.c net_sched: remove unused htb drop_list 2018-06-24 16:42:46 +09:00
sch_ingress.c net: sched: allow ingress and clsact qdiscs to share filter blocks 2018-01-17 14:53:57 -05:00
sch_mq.c net: sched: mq: request stats from offloads 2018-05-29 09:49:16 -04:00
sch_mqprio.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_multiq.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_netem.c netem: slotting with non-uniform distribution 2018-06-28 22:06:24 +09:00
sch_pie.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_plug.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_prio.c net: sch: prio: Add offload ability for grafting a child 2018-02-28 12:06:01 -05:00
sch_qfq.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_red.c net: sched: red: avoid hashing NULL child 2018-05-18 13:52:32 -04:00
sch_sfb.c net: sch: api: add extack support in qdisc_create_dflt 2017-12-21 12:32:51 -05:00
sch_sfq.c net: sch: api: add extack support in tcf_block_get 2017-12-21 12:32:51 -05:00
sch_skbprio.c net/sched: add skbprio scheduler 2018-07-24 14:44:00 -07:00
sch_tbf.c net: sched: red: avoid hashing NULL child 2018-05-18 13:52:32 -04:00
sch_teql.c net: sched: sch: add extack for init callback 2017-12-21 12:32:50 -05:00