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Message-Id: <6a2b33a90d699d12c3f8ea4d9b417341a8c0498c.1551288982.git.dcaratti@redhat.com>
Date: Wed, 27 Feb 2019 18:40:37 +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 09/16] net/sched: act_pedit: validate the control action inside init()
the following script:
# tc filter add dev crash0 egress matchall \
> action pedit ex munge ip ttl set 10 pass index 90
# tc actions replace action pedit \
> ex munge ip ttl set 10 goto chain 42 index 90 cookie c1a0c1a0
# tc actions show action pedit
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: pedit action goto chain 42 keys 1
index 90 ref 2 bind 1
key #0 at ipv4+8: val 0a000000 mask 00ffffff
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 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 0 Comm: swapper/2 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:ffff94a73db03be0 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff94a6ee4c0700 RCX: 000000000000000a
RDX: 0000000000000000 RSI: ffff94a6ed22c800 RDI: 0000000000000000
RBP: ffff94a73db03c80 R08: ffff94a7386fa4c8 R09: ffff94a73229ea20
R10: 0000000000000000 R11: 0000000000000000 R12: ffff94a6ed22cb00
R13: ffff94a6ed22cb08 R14: 0000000000000001 R15: ffff94a6ed22c800
FS: 0000000000000000(0000) GS:ffff94a73db00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007120e002 CR4: 00000000001606e0
Call Trace:
<IRQ>
tcf_classify+0x58/0x120
__dev_queue_xmit+0x40a/0x890
? ip6_finish_output2+0x369/0x590
ip6_finish_output2+0x369/0x590
? ip6_output+0x68/0x110
ip6_output+0x68/0x110
? nf_hook.constprop.35+0x79/0xc0
mld_sendpack+0x16f/0x220
mld_ifc_timer_expire+0x195/0x2c0
? igmp6_timer_handler+0x70/0x70
call_timer_fn+0x2b/0x130
run_timer_softirq+0x3e8/0x440
? tick_sched_timer+0x37/0x70
__do_softirq+0xe3/0x2f5
irq_exit+0xf0/0x100
smp_apic_timer_interrupt+0x6c/0x130
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:native_safe_halt+0x2/0x10
Code: 4e ff ff ff 7f f3 c3 65 48 8b 04 25 00 5c 01 00 f0 80 48 02 20 48 8b 00 a8 08 74 8b eb c1 90 90 90 90 90 90 90 90 90 90 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90
RSP: 0018:ffffab1740387eb8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffffb18184f0 RBX: 0000000000000002 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000087 RDI: 0000000000000002
RBP: 0000000000000002 R08: 000f168fa695f9a9 R09: 0000000000000020
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
? __sched_text_end+0x1/0x1
default_idle+0x1c/0x140
do_idle+0x1c4/0x280
cpu_startup_entry+0x19/0x20
start_secondary+0x1a7/0x200
secondary_startup_64+0xa4/0xb0
Modules linked in: act_pedit veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache jbd2 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep aesni_intel snd_hda_core crypto_simd snd_seq cryptd glue_helper snd_seq_device snd_pcm joydev snd_timer pcspkr virtio_balloon snd soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs qxl ata_generic pata_acpi drm_kms_helper virtio_net net_failover syscopyarea sysfillrect sysimgblt failover virtio_blk fb_sys_fops virtio_console ttm drm crc32c_intel serio_raw ata_piix virtio_pci libata virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000
Validating the control action within tcf_pedit_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_pedit.c | 17 ++++++-
.../tc-testing/tc-tests/actions/pedit.json | 51 +++++++++++++++++++
2 files changed, 66 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/tc-testing/tc-tests/actions/pedit.json
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 1c7a0db7b466..1eccd5053e70 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -23,6 +23,7 @@
#include <linux/tc_act/tc_pedit.h>
#include <net/tc_act/tc_pedit.h>
#include <uapi/linux/tc_act/tc_pedit.h>
+#include <net/pkt_cls.h>
static unsigned int pedit_net_id;
static struct tc_action_ops act_pedit_ops;
@@ -141,6 +142,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, pedit_net_id);
+ struct tcf_chain *newchain = NULL, *oldchain;
struct nlattr *tb[TCA_PEDIT_MAX + 1];
struct tc_pedit_key *keys = NULL;
struct tcf_pedit_key_ex *keys_ex;
@@ -205,6 +207,11 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
goto out_free;
}
+ err = tcf_action_check_ctrlact(parm->action, tp, &newchain, extack);
+ if (err) {
+ ret = err;
+ goto out_release;
+ }
p = to_pedit(*a);
spin_lock_bh(&p->tcf_lock);
@@ -214,7 +221,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
if (!keys) {
spin_unlock_bh(&p->tcf_lock);
ret = -ENOMEM;
- goto out_release;
+ goto put_chain;
}
kfree(p->tcfp_keys);
p->tcfp_keys = keys;
@@ -223,6 +230,8 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
memcpy(p->tcfp_keys, parm->keys, ksize);
p->tcfp_flags = parm->flags;
+ oldchain = p->tcf_goto_chain;
+ p->tcf_goto_chain = newchain;
p->tcf_action = parm->action;
kfree(p->tcfp_keys_ex);
@@ -231,14 +240,18 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
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;
+put_chain:
+ if (newchain)
+ tcf_chain_put_by_act(newchain);
out_release:
tcf_idr_release(*a, bind);
out_free:
kfree(keys_ex);
return ret;
-
}
static void tcf_pedit_cleanup(struct tc_action *a)
diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/pedit.json b/tools/testing/selftests/tc-testing/tc-tests/actions/pedit.json
new file mode 100644
index 000000000000..b73ceb9e28b1
--- /dev/null
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/pedit.json
@@ -0,0 +1,51 @@
+[
+ {
+ "id": "319a",
+ "name": "Add pedit action that mangles IP TTL",
+ "category": [
+ "actions",
+ "pedit"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action pedit",
+ 0,
+ 1,
+ 255
+ ]
+ ],
+ "cmdUnderTest": "$TC actions add action pedit ex munge ip ttl set 10",
+ "expExitCode": "0",
+ "verifyCmd": "$TC actions ls action pedit",
+ "matchPattern": "action order [0-9]+: pedit action pass keys 1.*index 1 ref.*key #0 at ipv4\\+8: val 0a000000 mask 00ffffff",
+ "matchCount": "1",
+ "teardown": [
+ "$TC actions flush action pedit"
+ ]
+ },
+ {
+ "id": "7e67",
+ "name": "Replace pedit action with invalid goto chain",
+ "category": [
+ "actions",
+ "pedit"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action pedit",
+ 0,
+ 1,
+ 255
+ ],
+ "$TC actions add action pedit ex munge ip ttl set 10 pass index 90"
+ ],
+ "cmdUnderTest": "$TC actions replace action pedit ex munge ip ttl set 10 goto chain 42 index 90 cookie c1a0c1a0",
+ "expExitCode": "255",
+ "verifyCmd": "$TC actions ls action pedit",
+ "matchPattern": "action order [0-9]+: pedit action pass keys 1.*index 90 ref.*key #0 at ipv4\\+8: val 0a000000 mask 00ffffff",
+ "matchCount": "1",
+ "teardown": [
+ "$TC actions flush action pedit"
+ ]
+ }
+]
--
2.20.1
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