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Message-Id: <8841253383de9c7230282f98c3081b96a729897f.1551288982.git.dcaratti@redhat.com>
Date: Wed, 27 Feb 2019 18:40:30 +0100
From: Davide Caratti <dcaratti@...hat.com>
To: "David S. Miller" <davem@...emloft.net>,
Jamal Hadi Salim <jhs@...atatu.com>,
Cong Wang <xiyou.wangcong@...il.com>,
Jiri Pirko <jiri@...nulli.us>,
Vlad Buslov <vladbu@...lanox.com>
Cc: pabeni@...hat.com, netdev@...r.kernel.org
Subject: [PATCH net 02/16] net/sched: act_bpf: validate the control action inside init()
the following script:
# tc filter add dev crash0 egress matchall \
> action bpf bytecode '1,6 0 0 4294967295' pass index 90
# tc actions replace action bpf \
> bytecode '1,6 0 0 4294967295' goto chain 42 index 90 cookie c1a0c1a0
# tc action show action bpf
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: bpf bytecode '1,6 0 0 4294967295' default-action goto chain 42
index 90 ref 2 bind 1
cookie c1a0c1a0
Then, the first packet transmitted by crash0 made the kernel crash:
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:ffffb3a0803dfa90 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff942b347ada00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffb3a08034d038 RDI: ffff942b347ada00
RBP: ffffb3a0803dfb30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffb3a0803dfb0c R12: ffff942b3b682b00
R13: ffff942b3b682b08 R14: 0000000000000001 R15: ffff942b3b682f00
FS: 00007f6160a72740(0000) GS:ffff942b3da80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000795a4002 CR4: 00000000001606e0
Call Trace:
tcf_classify+0x58/0x120
__dev_queue_xmit+0x40a/0x890
? ip_finish_output2+0x16f/0x430
ip_finish_output2+0x16f/0x430
? ip_output+0x69/0xe0
ip_output+0x69/0xe0
? ip_forward_options+0x1a0/0x1a0
ip_send_skb+0x15/0x40
raw_sendmsg+0x8e1/0xbd0
? sched_clock+0x5/0x10
? sched_clock_cpu+0xc/0xa0
? try_to_wake_up+0x54/0x480
? ldsem_down_read+0x3f/0x280
? _cond_resched+0x15/0x40
? down_read+0xe/0x30
? copy_termios+0x1e/0x70
? tty_mode_ioctl+0x1b6/0x4c0
? sock_sendmsg+0x36/0x40
sock_sendmsg+0x36/0x40
__sys_sendto+0x10e/0x140
? do_vfs_ioctl+0xa4/0x640
? handle_mm_fault+0xdc/0x210
? 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: 0033:0x7f615f7e3c03
Code: 48 8b 0d 90 62 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 9d c3 2c 00 00 75 13 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 4b cc 00 00 48 89 04 24
RSP: 002b:00007ffee5d8cc28 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055a4f28f1700 RCX: 00007f615f7e3c03
RDX: 0000000000000040 RSI: 000055a4f28f1700 RDI: 0000000000000003
RBP: 00007ffee5d8e340 R08: 000055a4f28ee510 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040
R13: 000055a4f28f16c0 R14: 000055a4f28ef69c R15: 0000000000000080
Modules linked in: act_bpf veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache crct10dif_pclmul jbd2 crc32_pclmul snd_hda_codec_generic 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 pcspkr joydev virtio_balloon snd_timer snd i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper virtio_blk virtio_net virtio_console net_failover failover syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crc32c_intel ata_piix serio_raw libata virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000
Validating the control action within tcf_bpf_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 <dcaratti@...hat.com>
---
net/sched/act_bpf.c | 13 ++++++++++
.../tc-testing/tc-tests/actions/bpf.json | 25 +++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 88a729bdab25..9aa24decffc4 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -17,6 +17,7 @@
#include <net/netlink.h>
#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
#include <linux/tc_act/tc_bpf.h>
#include <net/tc_act/tc_bpf.h>
@@ -281,6 +282,7 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, bpf_net_id);
+ struct tcf_chain *newchain = NULL, *oldchain;
struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
struct tcf_bpf_cfg cfg, old;
struct tc_act_bpf *parm;
@@ -323,6 +325,10 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
return ret;
}
+ ret = tcf_action_check_ctrlact(parm->action, tp, &newchain, extack);
+ if (ret < 0)
+ goto release_idr;
+
is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
is_ebpf = tb[TCA_ACT_BPF_FD];
@@ -350,6 +356,8 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
if (cfg.bpf_num_ops)
prog->bpf_num_ops = cfg.bpf_num_ops;
+ oldchain = prog->tcf_goto_chain;
+ prog->tcf_goto_chain = newchain;
prog->tcf_action = parm->action;
rcu_assign_pointer(prog->filter, cfg.filter);
spin_unlock_bh(&prog->tcf_lock);
@@ -361,9 +369,14 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
synchronize_rcu();
tcf_bpf_cfg_cleanup(&old);
}
+ if (oldchain)
+ tcf_chain_put_by_act(oldchain);
return res;
out:
+ if (newchain)
+ tcf_chain_put_by_act(newchain);
+release_idr:
tcf_idr_release(*act, bind);
return ret;
diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/bpf.json b/tools/testing/selftests/tc-testing/tc-tests/actions/bpf.json
index 5970cee6d05f..b074ea9b6fe8 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/bpf.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/bpf.json
@@ -286,5 +286,30 @@
"teardown": [
"$TC action flush action bpf"
]
+ },
+ {
+ "id": "b8a1",
+ "name": "Replace bpf action with invalid goto_chain control",
+ "category": [
+ "actions",
+ "bpf"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action bpf",
+ 0,
+ 1,
+ 255
+ ],
+ "$TC action add action bpf bytecode '1,6 0 0 4294967295' pass index 90"
+ ],
+ "cmdUnderTest": "$TC action replace action bpf bytecode '1,6 0 0 4294967295' goto chain 42 index 90 cookie c1a0c1a0",
+ "expExitCode": "255",
+ "verifyCmd": "$TC action list action bpf",
+ "matchPattern": "action order [0-9]*: bpf.* default-action pass.*index 90",
+ "matchCount": "1",
+ "teardown": [
+ "$TC action flush action bpf"
+ ]
}
]
--
2.20.1
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