From 5c905229641c62a1f1fe3df223c8e3ba63105880 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 27 Feb 2019 18:40:38 +0100 Subject: [PATCH] net/sched: act_police: validate the control action inside init() the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action police rate 3mbit burst 250k pass index 90 # tc actions replace action police \ > rate 3mbit burst 250k goto chain 42 index 90 cookie c1a0c1a0 # tc actions show action police rate 3mbit burst 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: police 0x5a rate 3Mbit burst 250Kb mtu 2Kb action goto chain 42 overhead 0b ref 2 bind 1 cookie c1a0c1a0 Then, when crash0 starts transmitting more than 3Mbit/s, the following kernel crash is observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] PGD 800000007a779067 P4D 800000007a779067 PUD 2ad96067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 3 PID: 5032 Comm: netperf Not tainted 5.0.0-rc4.gotochain_crash+ #533 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 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:ffffb0e04064fa60 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff93bb3322cce0 RCX: 0000000000000005 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff93bb3322cce0 RBP: ffffb0e04064fb00 R08: 0000000000000022 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff93bb3beed300 R13: ffff93bb3beed308 R14: 0000000000000001 R15: ffff93bb3b64d000 FS: 00007f0bc6be5740(0000) GS:ffff93bb3db80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000746a8001 CR4: 00000000001606e0 Call Trace: tcf_classify+0x58/0x120 __dev_queue_xmit+0x40a/0x890 ? ipt_do_table+0x31c/0x420 [ip_tables] ? ip_finish_output2+0x16f/0x430 ip_finish_output2+0x16f/0x430 ? ip_output+0x69/0xe0 ip_output+0x69/0xe0 ? ip_forward_options+0x1a0/0x1a0 __tcp_transmit_skb+0x563/0xa40 tcp_write_xmit+0x243/0xfa0 __tcp_push_pending_frames+0x32/0xf0 tcp_sendmsg_locked+0x404/0xd30 tcp_sendmsg+0x27/0x40 sock_sendmsg+0x36/0x40 __sys_sendto+0x10e/0x140 ? __sys_connect+0x87/0xf0 ? syscall_trace_enter+0x1df/0x2e0 ? __audit_syscall_exit+0x216/0x260 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f0bc5ffbafd Code: 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 8b 05 ae c4 2c 00 85 c0 75 2d 45 31 c9 45 31 c0 4c 63 d1 48 63 ff b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 63 63 2c 00 f7 d8 64 89 02 48 RSP: 002b:00007fffef94b7f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000004000 RCX: 00007f0bc5ffbafd RDX: 0000000000004000 RSI: 00000000017e5420 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 00000000017e51d0 R14: 0000000000000010 R15: 0000000000000006 Modules linked in: act_police veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 snd_hda_codec_generic mbcache crct10dif_pclmul jbd2 crc32_pclmul ghash_clmulni_intel snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd glue_helper snd_timer snd joydev pcspkr virtio_balloon 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 ttm drm virtio_blk virtio_net virtio_console net_failover failover crc32c_intel ata_piix libata serio_raw virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 Validating the control action within tcf_police_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 --- net/sched/act_police.c | 12 +++++++++ .../tc-testing/tc-tests/actions/police.json | 25 +++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/net/sched/act_police.c b/net/sched/act_police.c index a444dd78a24402..1f7b30b645e71a 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -21,6 +21,7 @@ #include #include #include +#include struct tcf_police_params { int tcfp_result; @@ -87,6 +88,7 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, struct netlink_ext_ack *extack) { int ret = 0, tcfp_result = TC_ACT_OK, err, size; + struct tcf_chain *newchain = NULL, *oldchain; struct nlattr *tb[TCA_POLICE_MAX + 1]; struct tc_police *parm; struct tcf_police *police; @@ -129,6 +131,9 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, tcf_idr_release(*a, bind); return -EEXIST; } + err = tcf_action_check_ctrlact(parm->action, tp, &newchain, extack); + if (err) + goto release_idr; police = to_police(*a); if (parm->rate.rate) { @@ -214,6 +219,8 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, if (new->peak_present) police->tcfp_ptoks = new->tcfp_mtu_ptoks; spin_unlock_bh(&police->tcfp_lock); + oldchain = police->tcf_goto_chain; + police->tcf_goto_chain = newchain; police->tcf_action = parm->action; rcu_swap_protected(police->params, new, @@ -225,11 +232,16 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a); + if (oldchain) + tcf_chain_put_by_act(oldchain); return ret; failure: qdisc_put_rtab(P_tab); qdisc_put_rtab(R_tab); + if (newchain) + tcf_chain_put_by_act(newchain); +release_idr: tcf_idr_release(*a, bind); return err; } diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/police.json b/tools/testing/selftests/tc-testing/tc-tests/actions/police.json index 4086a50a670ecb..b8268da5adaaa7 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/actions/police.json +++ b/tools/testing/selftests/tc-testing/tc-tests/actions/police.json @@ -739,5 +739,30 @@ "teardown": [ "$TC actions flush action police" ] + }, + { + "id": "689e", + "name": "Replace police action with invalid goto chain control", + "category": [ + "actions", + "police" + ], + "setup": [ + [ + "$TC actions flush action police", + 0, + 1, + 255 + ], + "$TC actions add action police rate 3mbit burst 250k drop index 90" + ], + "cmdUnderTest": "$TC actions replace action police rate 3mbit burst 250k goto chain 42 index 90 cookie c1a0c1a0", + "expExitCode": "255", + "verifyCmd": "$TC actions get action police index 90", + "matchPattern": "action order [0-9]*: police 0x5a rate 3Mbit burst 250Kb mtu 2Kb action drop", + "matchCount": "1", + "teardown": [ + "$TC actions flush action police" + ] } ]