linux/net/sched
Matteo Croce 25426043ec cls_matchall: avoid panic when receiving a packet before filter set
When a matchall classifier is added, there is a small time interval in
which tp->root is NULL. If we receive a packet in this small time slice
a NULL pointer dereference will happen, leading to a kernel panic:

    # tc qdisc replace dev eth0 ingress
    # tc filter add dev eth0 parent ffff: matchall action gact drop
    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000034
    Mem abort info:
      ESR = 0x96000005
      Exception class = DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
    Data abort info:
      ISV = 0, ISS = 0x00000005
      CM = 0, WnR = 0
    user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000a623d530
    [0000000000000034] pgd=0000000000000000, pud=0000000000000000
    Internal error: Oops: 96000005 [#1] SMP
    Modules linked in: cls_matchall sch_ingress nls_iso8859_1 nls_cp437 vfat fat m25p80 spi_nor mtd xhci_plat_hcd xhci_hcd phy_generic sfp mdio_i2c usbcore i2c_mv64xxx marvell10g mvpp2 usb_common spi_orion mvmdio i2c_core sbsa_gwdt phylink ip_tables x_tables autofs4
    Process ksoftirqd/0 (pid: 9, stack limit = 0x0000000009de7d62)
    CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.1.0-rc6 #21
    Hardware name: Marvell 8040 MACCHIATOBin Double-shot (DT)
    pstate: 40000005 (nZcv daif -PAN -UAO)
    pc : mall_classify+0x28/0x78 [cls_matchall]
    lr : tcf_classify+0x78/0x138
    sp : ffffff80109db9d0
    x29: ffffff80109db9d0 x28: ffffffc426058800
    x27: 0000000000000000 x26: ffffffc425b0dd00
    x25: 0000000020000000 x24: 0000000000000000
    x23: ffffff80109dbac0 x22: 0000000000000001
    x21: ffffffc428ab5100 x20: ffffffc425b0dd00
    x19: ffffff80109dbac0 x18: 0000000000000000
    x17: 0000000000000000 x16: 0000000000000000
    x15: 0000000000000000 x14: 0000000000000000
    x13: ffffffbf108ad288 x12: dead000000000200
    x11: 00000000f0000000 x10: 0000000000000001
    x9 : ffffffbf1089a220 x8 : 0000000000000001
    x7 : ffffffbebffaa950 x6 : 0000000000000000
    x5 : 000000442d6ba000 x4 : 0000000000000000
    x3 : ffffff8008735ad8 x2 : ffffff80109dbac0
    x1 : ffffffc425b0dd00 x0 : ffffff8010592078
    Call trace:
     mall_classify+0x28/0x78 [cls_matchall]
     tcf_classify+0x78/0x138
     __netif_receive_skb_core+0x29c/0xa20
     __netif_receive_skb_one_core+0x34/0x60
     __netif_receive_skb+0x28/0x78
     netif_receive_skb_internal+0x2c/0xc0
     napi_gro_receive+0x1a0/0x1d8
     mvpp2_poll+0x928/0xb18 [mvpp2]
     net_rx_action+0x108/0x378
     __do_softirq+0x128/0x320
     run_ksoftirqd+0x44/0x60
     smpboot_thread_fn+0x168/0x1b0
     kthread+0x12c/0x130
     ret_from_fork+0x10/0x1c
    Code: aa0203f3 aa1e03e0 d503201f f9400684 (b9403480)
    ---[ end trace fc71e2ef7b8ab5a5 ]---
    Kernel panic - not syncing: Fatal exception in interrupt
    SMP: stopping secondary CPUs
    Kernel Offset: disabled
    CPU features: 0x002,00002000
    Memory Limit: none
    Rebooting in 1 seconds..

Fix this by adding a NULL check in mall_classify().

Fixes: ed76f5edcc ("net: sched: protect filter_chain list with filter_chain_lock mutex")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-04 00:57:48 -04:00
..
act_api.c net/sched: let actions use RCU to access 'goto_chain' 2019-03-21 13:26:42 -07:00
act_bpf.c net/sched: act_bpf: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_connmark.c net/sched: act_connmark: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_csum.c net/sched: act_csum: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_gact.c net/sched: act_gact: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_ife.c net/sched: act_ife: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_ipt.c net/sched: prepare TC actions to properly validate the control action 2019-03-21 13:26:41 -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: fix cleanup NULL pointer exception in act_mirr 2019-03-23 21:36:04 -04:00
act_nat.c net/sched: act_nat: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_pedit.c net/sched: act_pedit: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_police.c net/sched: act_police: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_sample.c net/sched: act_sample: fix divide by zero in the traffic path 2019-04-04 10:46:33 -07:00
act_simple.c net/sched: act_simple: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_skbedit.c net/sched: act_skbedit: validate the control action inside init() 2019-03-21 13:26:41 -07:00
act_skbmod.c net/sched: act_skbmod: validate the control action inside init() 2019-03-21 13:26:42 -07:00
act_tunnel_key.c net/sched: act_tunnel_key: validate the control action inside init() 2019-03-21 13:26:42 -07:00
act_vlan.c net/sched: act_vlan: validate the control action inside init() 2019-03-21 13:26:42 -07:00
cls_api.c net/sched: let actions use RCU to access 'goto_chain' 2019-03-21 13:26:42 -07:00
cls_basic.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_bpf.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_cgroup.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_flow.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_flower.c net: sched: flower: insert new filter to idr after setting its mask 2019-03-06 10:52:16 -08:00
cls_fw.c Revert "net: sched: fw: don't set arg->stop in fw_walk() when empty" 2019-02-27 10:12:19 -08:00
cls_matchall.c cls_matchall: avoid panic when receiving a packet before filter set 2019-05-04 00:57:48 -04:00
cls_route.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_rsvp6.c
cls_rsvp.c
cls_rsvp.h net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_tcindex.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
cls_u32.c net_sched: initialize net pointer inside tcf_exts_init() 2019-02-22 15:26:51 -08:00
em_canid.c
em_cmp.c
em_ipset.c
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
em_u32.c
ematch.c net: sched: ematch: obtain net pointer from blocks 2017-10-16 21:00:40 +01:00
Kconfig net: sched: Kconfig: update reference link for PIE 2019-03-26 11:17:09 -07:00
Makefile tc: Add support for configuring the taprio scheduler 2018-10-04 13:52:23 -07:00
sch_api.c net_sched: return correct value for *notify* functions 2019-03-13 13:48:27 -07:00
sch_atm.c net: sched: rename qdisc_destroy() to qdisc_put() 2018-09-25 20:17:35 -07:00
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: Make sure we can write the IP header before changing DSCP bits 2019-04-04 10:55:59 -07:00
sch_cbq.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_cbs.c sched: Avoid dereferencing skb pointer after child enqueue 2019-01-15 20:12:00 -08:00
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: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_dsmark.c sched: Avoid dereferencing skb pointer after child enqueue 2019-01-15 20:12:00 -08:00
sch_etf.c etf: Drop all expired packets 2018-11-16 20:39:34 -08:00
sch_fifo.c net: sched: rename qdisc_destroy() to qdisc_put() 2018-09-25 20:17:35 -07:00
sch_fq_codel.c net: Add and use skb_mark_not_on_list(). 2018-09-10 10:06:54 -07:00
sch_fq.c net_sched: sch_fq: avoid calling ktime_get_ns() if not needed 2018-11-20 09:51:32 -08:00
sch_generic.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-04 13:26:15 -08:00
sch_gred.c net: sched: gred: support reporting stats from offloads 2018-11-19 18:53:46 -08:00
sch_hfsc.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_hhf.c net: Add and use skb_mark_not_on_list(). 2018-09-10 10:06:54 -07:00
sch_htb.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
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: introduce and use qstats read helpers 2019-04-01 14:50:13 -07:00
sch_mqprio.c net: sched: introduce and use qstats read helpers 2019-04-01 14:50:13 -07:00
sch_multiq.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_netem.c net: netem: fix skb length BUG_ON in __skb_to_sgvec 2019-02-28 10:31:31 -08:00
sch_pie.c net: sched: pie: avoid slow division in drop probability decay 2019-02-28 10:35:41 -08:00
sch_plug.c net: sched: sch: add extack for change qdisc ops 2017-12-21 12:32:50 -05:00
sch_prio.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_qfq.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_red.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_sfb.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
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_taprio.c net: sched: introduce and use qstats read helpers 2019-04-01 14:50:13 -07:00
sch_tbf.c net: sched: introduce and use qdisc tree flush/purge helpers 2019-04-01 14:50:13 -07:00
sch_teql.c net: sched: sch: add extack for init callback 2017-12-21 12:32:50 -05:00