From e8c87c643ef3603c6e63bdecb67b03d794648493 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 20 Mar 2019 15:00:09 +0100 Subject: net/sched: act_sample: validate the control action inside init() the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action sample rate 1024 group 4 pass index 90 # tc actions replace action sample \ > rate 1024 group 4 goto chain 42 index 90 cookie c1a0c1a0 # tc actions show action sample had the following output: Error: Failed to init TC action chain. We have an error talking to the kernel total acts 1 action order 0: sample rate 1/1024 group 4 goto chain 42 index 90 ref 2 bind 1 cookie c1a0c1a0 Then, the first packet transmitted by crash0 made the kernel crash: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] PGD 8000000079966067 P4D 8000000079966067 PUD 7987b067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.0.0-rc4.gotochain_crash+ #536 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:tcf_action_exec+0xb8/0x100 Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 RSP: 0018:ffffbee60033fad0 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff99d7ae6e3b00 RCX: 00000000e555df9b RDX: 0000000000000000 RSI: 00000000b0352718 RDI: ffff99d7fda1fcf0 RBP: ffffbee60033fb70 R08: 0000000070731ab1 R09: 0000000000000400 R10: 0000000000000000 R11: ffff99d7ac733838 R12: ffff99d7f3c2be00 R13: ffff99d7f3c2be08 R14: 0000000000000001 R15: ffff99d7f3c2b600 FS: 0000000000000000(0000) GS:ffff99d7fda00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000797de006 CR4: 00000000001606f0 Call Trace: tcf_classify+0x58/0x120 __dev_queue_xmit+0x40a/0x890 ? ndisc_next_option+0x50/0x50 ? ___neigh_create+0x4d5/0x680 ? ip6_finish_output2+0x1b5/0x590 ip6_finish_output2+0x1b5/0x590 ? ip6_output+0x68/0x110 ip6_output+0x68/0x110 ? nf_hook.constprop.28+0x79/0xc0 ndisc_send_skb+0x248/0x2e0 ndisc_send_ns+0xf8/0x200 ? addrconf_dad_work+0x389/0x4b0 addrconf_dad_work+0x389/0x4b0 ? __switch_to_asm+0x34/0x70 ? process_one_work+0x195/0x380 ? addrconf_dad_completed+0x370/0x370 process_one_work+0x195/0x380 worker_thread+0x30/0x390 ? process_one_work+0x380/0x380 kthread+0x113/0x130 ? kthread_park+0x90/0x90 ret_from_fork+0x35/0x40 Modules linked in: act_sample psample veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel mbcache jbd2 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device aesni_intel crypto_simd snd_pcm cryptd glue_helper snd_timer joydev snd pcspkr virtio_balloon i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect virtio_net sysimgblt fb_sys_fops net_failover ttm failover virtio_blk virtio_console drm ata_piix serio_raw crc32c_intel libata virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 Validating the control action within tcf_sample_init() proved to fix the above issue. A TDC selftest is added to verify the correct behavior. Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain") Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values") Signed-off-by: Davide Caratti Signed-off-by: David S. Miller --- net/sched/act_sample.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c index 36b8adbe935d..4060b0955c97 100644 --- a/net/sched/act_sample.c +++ b/net/sched/act_sample.c @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -43,6 +44,7 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla, struct tc_action_net *tn = net_generic(net, sample_net_id); struct nlattr *tb[TCA_SAMPLE_MAX + 1]; struct psample_group *psample_group; + struct tcf_chain *goto_ch = NULL; struct tc_sample *parm; u32 psample_group_num; struct tcf_sample *s; @@ -79,18 +81,21 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla, tcf_idr_release(*a, bind); return -EEXIST; } + err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); + if (err < 0) + goto release_idr; psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); psample_group = psample_group_get(net, psample_group_num); if (!psample_group) { - tcf_idr_release(*a, bind); - return -ENOMEM; + err = -ENOMEM; + goto put_chain; } s = to_sample(*a); spin_lock_bh(&s->tcf_lock); - s->tcf_action = parm->action; + goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); s->psample_group_num = psample_group_num; RCU_INIT_POINTER(s->psample_group, psample_group); @@ -100,10 +105,18 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla, s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); } spin_unlock_bh(&s->tcf_lock); + if (goto_ch) + tcf_chain_put_by_act(goto_ch); if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a); return ret; +put_chain: + if (goto_ch) + tcf_chain_put_by_act(goto_ch); +release_idr: + tcf_idr_release(*a, bind); + return err; } static void tcf_sample_cleanup(struct tc_action *a) -- cgit v1.2.3