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Message-Id: <b7d4c2881256b3f771d66b956eb7ba2d4c4318e8.1551288982.git.dcaratti@redhat.com>
Date: Wed, 27 Feb 2019 18:40:36 +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 08/16] net/sched: act_nat: validate the control action inside init()
the following script:
# tc qdisc add dev crash0 clsact
# tc filter add dev crash0 egress matchall \
> action nat ingress 1.18.1.1 1.18.2.2 pass index 90
# tc actions replace action nat \
> ingress 1.18.1.1 1.18.2.2 goto chain 42 index 90 cookie c1a0c1a0
# tc actions show action nat
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: nat ingress 1.18.1.1/32 1.18.2.2 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 800000002d180067 P4D 800000002d180067 PUD 7cb8b067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 164 Comm: kworker/3:1 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:ffffae4500e2fad0 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff9fa52e28c800 RCX: 0000000001011201
RDX: 0000000000000000 RSI: 0000000000000056 RDI: ffff9fa52ca12800
RBP: ffffae4500e2fb70 R08: 0000000000000022 R09: 000000000000000e
R10: 00000000ffffffff R11: 0000000001011201 R12: ffff9fa52cbc9c00
R13: ffff9fa52cbc9c08 R14: 0000000000000001 R15: ffff9fa52ca12780
FS: 0000000000000000(0000) GS:ffff9fa57db80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000073f8c004 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_nat 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 snd_pcm aesni_intel crypto_simd cryptd glue_helper snd_timer snd joydev virtio_balloon pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs qxl ata_generic pata_acpi drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm virtio_net virtio_blk net_failover failover virtio_console drm crc32c_intel floppy ata_piix libata virtio_pci virtio_ring virtio serio_raw dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000
Validating the control action within tcf_nat_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_nat.c | 12 +++++++++
.../tc-testing/tc-tests/actions/nat.json | 25 +++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 526c4c99bcce..97aa55b4b268 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -21,6 +21,7 @@
#include <linux/string.h>
#include <linux/tc_act/tc_nat.h>
#include <net/act_api.h>
+#include <net/pkt_cls.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/netlink.h>
@@ -42,6 +43,7 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, nat_net_id);
+ struct tcf_chain *newchain = NULL, *oldchain;
struct nlattr *tb[TCA_NAT_MAX + 1];
struct tc_nat *parm;
int ret = 0, err;
@@ -77,6 +79,9 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
} else {
return err;
}
+ err = tcf_action_check_ctrlact(parm->action, tp, &newchain, extack);
+ if (err)
+ goto release_idr;
p = to_tcf_nat(*a);
spin_lock_bh(&p->tcf_lock);
@@ -85,13 +90,20 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
p->mask = parm->mask;
p->flags = parm->flags;
+ oldchain = p->tcf_goto_chain;
+ p->tcf_goto_chain = newchain;
p->tcf_action = parm->action;
spin_unlock_bh(&p->tcf_lock);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
+ if (oldchain)
+ tcf_chain_put_by_act(oldchain);
return ret;
+release_idr:
+ tcf_idr_release(*a, bind);
+ return err;
}
static int tcf_nat_act(struct sk_buff *skb, const struct tc_action *a,
diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/nat.json b/tools/testing/selftests/tc-testing/tc-tests/actions/nat.json
index 0080dc2fd41c..bc12c1ccad30 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/nat.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/nat.json
@@ -589,5 +589,30 @@
"teardown": [
"$TC actions flush action nat"
]
+ },
+ {
+ "id": "4b12",
+ "name": "Replace nat action with invalid goto chain control",
+ "category": [
+ "actions",
+ "nat"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action nat",
+ 0,
+ 1,
+ 255
+ ],
+ "$TC actions add action nat ingress 1.18.1.1 1.18.2.2 drop index 90"
+ ],
+ "cmdUnderTest": "$TC actions replace action nat ingress 1.18.1.1 1.18.2.2 goto chain 42 index 90 cookie c1a0c1a0",
+ "expExitCode": "255",
+ "verifyCmd": "$TC actions get action nat index 90",
+ "matchPattern": "action order [0-9]+: nat ingress 1.18.1.1/32 1.18.2.2 drop.*index 90 ref",
+ "matchCount": "1",
+ "teardown": [
+ "$TC actions flush action nat"
+ ]
}
]
--
2.20.1
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