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Message-Id: <1db930565d2ff547eecefb5418effabed65660ab.1551288982.git.dcaratti@redhat.com>
Date: Wed, 27 Feb 2019 18:40:40 +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 12/16] net/sched: act_simple: validate the control action inside init()
the following script:
# tc qdisc add dev crash0 clsact
# tc filter add dev crash0 egress matchall \
> action simple sdata hello pass index 90
# tc actions replace action simple \
> sdata world goto chain 42 index 90 cookie c1a0c1a0
# tc action show action simple
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: Simple <world>
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 800000006a6fb067 P4D 800000006a6fb067 PUD 6aed6067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 3241 Comm: kworker/2:0 Not tainted 5.0.0-rc4.gotochain_crash+ #536
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:ffffbe6781763ad0 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff9e59bdb80e00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff9e59b4716738 RDI: ffff9e59ab12d140
RBP: ffffbe6781763b70 R08: 0000000000000234 R09: 0000000000aaaaaa
R10: 0000000000000000 R11: ffff9e59b247cd50 R12: ffff9e59b112f100
R13: ffff9e59b112f108 R14: 0000000000000001 R15: ffff9e59ab12d0c0
FS: 0000000000000000(0000) GS:ffff9e59b4700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000006af92004 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_simple veth ip6table_filter ip6_tables iptable_filter binfmt_misc crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ext4 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep mbcache snd_hda_core jbd2 snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd snd_timer glue_helper snd joydev virtio_balloon pcspkr 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 virtio_net ttm net_failover virtio_console virtio_blk failover drm crc32c_intel serio_raw floppy ata_piix libata virtio_pci virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000
Validating the control action within tcf_simple_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_simple.c | 50 +++++++++++++++----
.../tc-testing/tc-tests/actions/simple.json | 25 ++++++++++
2 files changed, 65 insertions(+), 10 deletions(-)
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 640ee5b785dc..ca8ef8378c33 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -18,6 +18,7 @@
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
#define TCA_ACT_SIMP 22
@@ -62,14 +63,28 @@ static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)
return 0;
}
-static void reset_policy(struct tcf_defact *d, const struct nlattr *defdata,
- struct tc_defact *p)
+static int reset_policy(struct tcf_defact *d, const struct nlattr *defdata,
+ struct tc_defact *p, struct tcf_proto *tp,
+ struct netlink_ext_ack *extack)
{
+ struct tcf_chain *newchain = NULL, *oldchain;
+ int err;
+
+ err = tcf_action_check_ctrlact(p->action, tp, &newchain, extack);
+ if (err)
+ return err;
+
spin_lock_bh(&d->tcf_lock);
+ oldchain = d->tcf_goto_chain;
+ d->tcf_goto_chain = newchain;
d->tcf_action = p->action;
memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
spin_unlock_bh(&d->tcf_lock);
+
+ if (oldchain)
+ tcf_chain_put_by_act(oldchain);
+ return err;
}
static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
@@ -83,6 +98,7 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, simp_net_id);
+ struct tcf_chain *newchain = NULL, *oldchain;
struct nlattr *tb[TCA_DEF_MAX + 1];
struct tc_defact *parm;
struct tcf_defact *d;
@@ -124,27 +140,41 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
}
d = to_defact(*a);
- ret = alloc_defdata(d, tb[TCA_DEF_DATA]);
- if (ret < 0) {
- tcf_idr_release(*a, bind);
- return ret;
- }
+ err = tcf_action_check_ctrlact(parm->action, tp, &newchain,
+ extack);
+ if (err < 0)
+ goto release_idr;
+
+ err = alloc_defdata(d, tb[TCA_DEF_DATA]);
+ if (err < 0)
+ goto release_idr;
+
+ oldchain = d->tcf_goto_chain;
+ d->tcf_goto_chain = newchain;
d->tcf_action = parm->action;
+ if (oldchain)
+ tcf_chain_put_by_act(oldchain);
ret = ACT_P_CREATED;
} else {
d = to_defact(*a);
if (!ovr) {
- tcf_idr_release(*a, bind);
- return -EEXIST;
+ err = -EEXIST;
+ goto release_idr;
}
- reset_policy(d, tb[TCA_DEF_DATA], parm);
+ err = reset_policy(d, tb[TCA_DEF_DATA], parm, tp, extack);
+ if (err)
+ goto release_idr;
}
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
return ret;
+
+release_idr:
+ tcf_idr_release(*a, bind);
+ return err;
}
static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json b/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json
index e89a7aa4012d..8e8c1ae12260 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/simple.json
@@ -126,5 +126,30 @@
"teardown": [
""
]
+ },
+ {
+ "id": "b776",
+ "name": "Replace simple action with invalid goto chain control",
+ "category": [
+ "actions",
+ "simple"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action simple",
+ 0,
+ 1,
+ 255
+ ],
+ "$TC actions add action simple sdata \"hello\" pass index 90"
+ ],
+ "cmdUnderTest": "$TC actions replace action simple sdata \"world\" goto chain 42 index 90 cookie c1a0c1a0",
+ "expExitCode": "255",
+ "verifyCmd": "$TC actions list action simple",
+ "matchPattern": "action order [0-9]*: Simple <hello>.*index 90 ref",
+ "matchCount": "1",
+ "teardown": [
+ "$TC actions flush action simple"
+ ]
}
]
--
2.20.1
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