From 4b006b0c139e486773335f4c23b4d82348cfeb04 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 20 Mar 2019 15:00:10 +0100 Subject: [PATCH] net/sched: act_simple: validate the control action inside init() the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action simple sdata hello pass index 90 # tc actions replace action simple \ > sdata world goto chain 42 index 90 cookie c1a0c1a0 # tc action show action simple 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: Simple 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 800000006a6fb067 P4D 800000006a6fb067 PUD 6aed6067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 2 PID: 3241 Comm: kworker/2:0 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:ffffbe6781763ad0 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff9e59bdb80e00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9e59b4716738 RDI: ffff9e59ab12d140 RBP: ffffbe6781763b70 R08: 0000000000000234 R09: 0000000000aaaaaa R10: 0000000000000000 R11: ffff9e59b247cd50 R12: ffff9e59b112f100 R13: ffff9e59b112f108 R14: 0000000000000001 R15: ffff9e59ab12d0c0 FS: 0000000000000000(0000) GS:ffff9e59b4700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000006af92004 CR4: 00000000001606e0 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_simple veth ip6table_filter ip6_tables iptable_filter binfmt_misc crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ext4 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep mbcache snd_hda_core jbd2 snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd snd_timer glue_helper snd joydev virtio_balloon pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops virtio_net ttm net_failover virtio_console virtio_blk failover drm crc32c_intel serio_raw floppy ata_piix libata virtio_pci virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 Validating the control action within tcf_simple_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_simple.c | 52 ++++++++++++++----- .../tc-testing/tc-tests/actions/simple.json | 25 +++++++++ 2 files changed, 63 insertions(+), 14 deletions(-) diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c index 4916dc3e3668..23c8ca5615e5 100644 --- a/net/sched/act_simple.c +++ b/net/sched/act_simple.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -60,14 +61,26 @@ static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata) return 0; } -static void reset_policy(struct tcf_defact *d, const struct nlattr *defdata, - struct tc_defact *p) +static int reset_policy(struct tc_action *a, const struct nlattr *defdata, + struct tc_defact *p, struct tcf_proto *tp, + struct netlink_ext_ack *extack) { + struct tcf_chain *goto_ch = NULL; + struct tcf_defact *d; + int err; + + err = tcf_action_check_ctrlact(p->action, tp, &goto_ch, extack); + if (err < 0) + return err; + d = to_defact(a); spin_lock_bh(&d->tcf_lock); - d->tcf_action = p->action; + goto_ch = tcf_action_set_ctrlact(a, p->action, goto_ch); memset(d->tcfd_defdata, 0, SIMP_MAX_DATA); nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); spin_unlock_bh(&d->tcf_lock); + if (goto_ch) + tcf_chain_put_by_act(goto_ch); + return 0; } static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = { @@ -82,6 +95,7 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla, { struct tc_action_net *tn = net_generic(net, simp_net_id); struct nlattr *tb[TCA_DEF_MAX + 1]; + struct tcf_chain *goto_ch = NULL; struct tc_defact *parm; struct tcf_defact *d; bool exists = false; @@ -122,27 +136,37 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla, } d = to_defact(*a); - ret = alloc_defdata(d, tb[TCA_DEF_DATA]); - if (ret < 0) { - tcf_idr_release(*a, bind); - return ret; - } - d->tcf_action = parm->action; + err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, + extack); + if (err < 0) + goto release_idr; + + err = alloc_defdata(d, tb[TCA_DEF_DATA]); + if (err < 0) + goto put_chain; + + tcf_action_set_ctrlact(*a, parm->action, goto_ch); ret = ACT_P_CREATED; } else { - d = to_defact(*a); - if (!ovr) { - tcf_idr_release(*a, bind); - return -EEXIST; + err = -EEXIST; + goto release_idr; } - reset_policy(d, tb[TCA_DEF_DATA], parm); + err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack); + if (err) + goto release_idr; } 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 int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a, diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json b/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json index e89a7aa4012d..8e8c1ae12260 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json +++ b/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json @@ -126,5 +126,30 @@ "teardown": [ "" ] + }, + { + "id": "b776", + "name": "Replace simple action with invalid goto chain control", + "category": [ + "actions", + "simple" + ], + "setup": [ + [ + "$TC actions flush action simple", + 0, + 1, + 255 + ], + "$TC actions add action simple sdata \"hello\" pass index 90" + ], + "cmdUnderTest": "$TC actions replace action simple sdata \"world\" goto chain 42 index 90 cookie c1a0c1a0", + "expExitCode": "255", + "verifyCmd": "$TC actions list action simple", + "matchPattern": "action order [0-9]*: Simple .*index 90 ref", + "matchCount": "1", + "teardown": [ + "$TC actions flush action simple" + ] } ] -- 2.39.5