the following script:
# tc qdisc add dev crash0 clsact
# tc filter add dev crash0 egress matchall \
> action connmark pass index 90
# tc actions replace action connmark \
> goto chain 42 index 90 cookie
c1a0c1a0
# tc actions show action connmark
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: connmark zone 0 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 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 302 Comm: kworker/0:2 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:
ffff9bea406c3ad0 EFLAGS:
00010246
RAX:
000000002000002a RBX:
ffff8c5dfc009f00 RCX:
0000000000000000
RDX:
0000000000000000 RSI:
ffff9bea406c3a80 RDI:
ffff8c5dfb9d6ec0
RBP:
ffff9bea406c3b70 R08:
ffff8c5dfda222a0 R09:
ffffffff90933c3c
R10:
0000000000000000 R11:
0000000092793f7d R12:
ffff8c5df48b3c00
R13:
ffff8c5df48b3c08 R14:
0000000000000001 R15:
ffff8c5dfb9d6e40
FS:
0000000000000000(0000) GS:
ffff8c5dfda00000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
0000000000000000 CR3:
0000000062e0e006 CR4:
00000000001606f0
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_connmark nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 crct10dif_pclmul mbcache crc32_pclmul jbd2 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 snd_timer crypto_simd cryptd snd glue_helper 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 virtio_net net_failover syscopyarea virtio_blk failover virtio_console sysfillrect sysimgblt fb_sys_fops ttm drm ata_piix crc32c_intel 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_connmark_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@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/act_api.h>
+#include <net/pkt_cls.h>
#include <uapi/linux/tc_act/tc_connmark.h>
#include <net/tc_act/tc_connmark.h>
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
struct nlattr *tb[TCA_CONNMARK_MAX + 1];
+ struct tcf_chain *goto_ch = NULL;
struct tcf_connmark_info *ci;
struct tc_connmark *parm;
- int ret = 0;
+ int ret = 0, err;
if (!nla)
return -EINVAL;
}
ci = to_connmark(*a);
- ci->tcf_action = parm->action;
+ err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
+ extack);
+ if (err < 0)
+ goto release_idr;
+ tcf_action_set_ctrlact(*a, parm->action, goto_ch);
ci->net = net;
ci->zone = parm->zone;
tcf_idr_release(*a, bind);
return -EEXIST;
}
+ err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
+ extack);
+ if (err < 0)
+ goto release_idr;
/* replacing action and zone */
spin_lock_bh(&ci->tcf_lock);
- ci->tcf_action = parm->action;
+ goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
ci->zone = parm->zone;
spin_unlock_bh(&ci->tcf_lock);
+ if (goto_ch)
+ tcf_chain_put_by_act(goto_ch);
ret = 0;
}
return ret;
+release_idr:
+ tcf_idr_release(*a, bind);
+ return err;
}
static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
"teardown": [
"$TC actions flush action connmark"
]
+ },
+ {
+ "id": "c506",
+ "name": "Replace connmark with invalid goto chain control",
+ "category": [
+ "actions",
+ "connmark"
+ ],
+ "setup": [
+ [
+ "$TC actions flush action connmark",
+ 0,
+ 1,
+ 255
+ ],
+ "$TC actions add action connmark pass index 90"
+ ],
+ "cmdUnderTest": "$TC actions replace action connmark goto chain 42 index 90 cookie c1a0c1a0",
+ "expExitCode": "255",
+ "verifyCmd": "$TC actions get action connmark index 90",
+ "matchPattern": "action order [0-9]+: connmark zone 0 pass.*index 90 ref",
+ "matchCount": "1",
+ "teardown": [
+ "$TC actions flush action connmark"
+ ]
}
]
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