From 11a94d7fd80f92325e7b8653290ad3d2cd67f119 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 20 Mar 2019 15:00:03 +0100 Subject: [PATCH] net/sched: act_ife: validate the control action inside init() the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action ife encode allow mark pass index 90 # tc actions replace action ife \ > encode allow mark goto chain 42 index 90 cookie c1a0c1a0 # tc action show action ife had the following output: IFE type 0xED3E IFE type 0xED3E Error: Failed to init TC action chain. We have an error talking to the kernel total acts 1 action order 0: ife encode action goto chain 42 type 0XED3E allow mark 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 800000007b4e7067 P4D 800000007b4e7067 PUD 7b4e6067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 2 PID: 164 Comm: kworker/2:1 Not tainted 5.0.0-rc4.gotochain_crash+ #533 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:ffffa6a7c0553ad0 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff9796ee1bbd00 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffa6a7c0553b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffff9797385bb038 R12: ffff9796ead9d700 R13: ffff9796ead9d708 R14: 0000000000000001 R15: ffff9796ead9d800 FS: 0000000000000000(0000) GS:ffff97973db00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007c41e006 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_gact act_meta_mark act_ife dummy veth ip6table_filter ip6_tables iptable_filter binfmt_misc snd_hda_codec_generic ext4 snd_hda_intel snd_hda_codec crct10dif_pclmul mbcache crc32_pclmul jbd2 snd_hwdep snd_hda_core ghash_clmulni_intel snd_seq snd_seq_device snd_pcm snd_timer aesni_intel crypto_simd snd cryptd glue_helper virtio_balloon joydev pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl virtio_net drm_kms_helper virtio_blk net_failover syscopyarea failover sysfillrect virtio_console sysimgblt fb_sys_fops ttm drm crc32c_intel serio_raw ata_piix virtio_pci virtio_ring libata virtio floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: act_ife] CR2: 0000000000000000 Validating the control action within tcf_ife_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_ife.c | 33 +++++++++++-------- .../tc-testing/tc-tests/actions/ife.json | 25 ++++++++++++++ 2 files changed, 45 insertions(+), 13 deletions(-) diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index c1ba74d5c1e38a..31c6ffb6abe7c6 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -474,6 +475,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, struct tc_action_net *tn = net_generic(net, ife_net_id); struct nlattr *tb[TCA_IFE_MAX + 1]; struct nlattr *tb2[IFE_META_MAX + 1]; + struct tcf_chain *goto_ch = NULL; struct tcf_ife_params *p; struct tcf_ife_info *ife; u16 ife_type = ETH_P_IFE; @@ -531,6 +533,10 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, } ife = to_ife(*a); + err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); + if (err < 0) + goto release_idr; + p->flags = parm->flags; if (parm->flags & IFE_ENCODE) { @@ -563,13 +569,8 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, if (tb[TCA_IFE_METALST]) { err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST], NULL, NULL); - if (err) { -metadata_parse_err: - tcf_idr_release(*a, bind); - kfree(p); - return err; - } - + if (err) + goto metadata_parse_err; err = populate_metalist(ife, tb2, exists, rtnl_held); if (err) goto metadata_parse_err; @@ -581,21 +582,20 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, * going to bail out */ err = use_all_metadata(ife, exists); - if (err) { - tcf_idr_release(*a, bind); - kfree(p); - return err; - } + if (err) + goto metadata_parse_err; } if (exists) spin_lock_bh(&ife->tcf_lock); - ife->tcf_action = parm->action; /* protected by tcf_lock when modifying existing action */ + goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); rcu_swap_protected(ife->params, p, 1); if (exists) spin_unlock_bh(&ife->tcf_lock); + if (goto_ch) + tcf_chain_put_by_act(goto_ch); if (p) kfree_rcu(p, rcu); @@ -603,6 +603,13 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, tcf_idr_insert(tn, *a); return ret; +metadata_parse_err: + if (goto_ch) + tcf_chain_put_by_act(goto_ch); +release_idr: + kfree(p); + tcf_idr_release(*a, bind); + return err; } static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind, diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/ife.json b/tools/testing/selftests/tc-testing/tc-tests/actions/ife.json index 0da3545cabdb62..c13a68b98fc775 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/actions/ife.json +++ b/tools/testing/selftests/tc-testing/tc-tests/actions/ife.json @@ -1060,5 +1060,30 @@ "matchPattern": "action order [0-9]*: ife encode action pipe.*allow prio.*index 4", "matchCount": "0", "teardown": [] + }, + { + "id": "a0e2", + "name": "Replace ife encode action with invalid goto chain control", + "category": [ + "actions", + "ife" + ], + "setup": [ + [ + "$TC actions flush action ife", + 0, + 1, + 255 + ], + "$TC actions add action ife encode allow mark pass index 90" + ], + "cmdUnderTest": "$TC actions replace action ife encode allow mark goto chain 42 index 90 cookie c1a0c1a0", + "expExitCode": "255", + "verifyCmd": "$TC actions get action ife index 90", + "matchPattern": "action order [0-9]*: ife encode action pass.*type 0[xX]ED3E .*allow mark.*index 90 ref", + "matchCount": "1", + "teardown": [ + "$TC actions flush action ife" + ] } ]