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Message-Id: <a51604fe9879237dad3f2417bec2b7c12061dba7.1551288982.git.dcaratti@redhat.com>
Date: Wed, 27 Feb 2019 18:40:33 +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 05/16] 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 <dcaratti@...hat.com>
---
net/sched/act_ife.c | 32 ++++++++++++-------
.../tc-testing/tc-tests/actions/ife.json | 25 +++++++++++++++
2 files changed, 45 insertions(+), 12 deletions(-)
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 9b2eb941e093..4480edb386d7 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -29,6 +29,7 @@
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
#include <uapi/linux/tc_act/tc_ife.h>
#include <net/tc_act/tc_ife.h>
#include <linux/etherdevice.h>
@@ -472,6 +473,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, ife_net_id);
+ struct tcf_chain *newchain = NULL, *oldchain;
struct nlattr *tb[TCA_IFE_MAX + 1];
struct nlattr *tb2[IFE_META_MAX + 1];
struct tcf_ife_params *p;
@@ -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, &newchain, extack);
+ if (err)
+ 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;
@@ -581,15 +582,14 @@ 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);
+ oldchain = ife->tcf_goto_chain;
+ ife->tcf_goto_chain = newchain;
ife->tcf_action = parm->action;
/* protected by tcf_lock when modifying existing action */
rcu_swap_protected(ife->params, p, 1);
@@ -603,6 +603,14 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
tcf_idr_insert(tn, *a);
return ret;
+
+metadata_parse_err:
+ if (newchain)
+ tcf_chain_put_by_act(newchain);
+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 0da3545cabdb..c13a68b98fc7 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"
+ ]
}
]
--
2.20.1
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