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: db50514f9a ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f4 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Davide Caratti
David S. Miller
parent
0da2dbd602
commit
11a94d7fd8
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@ -29,6 +29,7 @@
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#include <net/net_namespace.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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#include <uapi/linux/tc_act/tc_ife.h>
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#include <net/tc_act/tc_ife.h>
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#include <linux/etherdevice.h>
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@ -474,6 +475,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
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struct tc_action_net *tn = net_generic(net, ife_net_id);
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struct nlattr *tb[TCA_IFE_MAX + 1];
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struct nlattr *tb2[IFE_META_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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struct tcf_ife_params *p;
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struct tcf_ife_info *ife;
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u16 ife_type = ETH_P_IFE;
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@ -531,6 +533,10 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
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}
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ife = to_ife(*a);
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err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
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if (err < 0)
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goto release_idr;
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p->flags = parm->flags;
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if (parm->flags & IFE_ENCODE) {
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@ -563,13 +569,8 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
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if (tb[TCA_IFE_METALST]) {
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err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
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NULL, NULL);
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if (err) {
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metadata_parse_err:
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tcf_idr_release(*a, bind);
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kfree(p);
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return err;
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}
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if (err)
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goto metadata_parse_err;
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err = populate_metalist(ife, tb2, exists, rtnl_held);
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if (err)
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goto metadata_parse_err;
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@ -581,21 +582,20 @@ metadata_parse_err:
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* going to bail out
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*/
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err = use_all_metadata(ife, exists);
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if (err) {
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tcf_idr_release(*a, bind);
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kfree(p);
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return err;
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}
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if (err)
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goto metadata_parse_err;
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}
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if (exists)
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spin_lock_bh(&ife->tcf_lock);
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ife->tcf_action = parm->action;
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/* protected by tcf_lock when modifying existing action */
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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rcu_swap_protected(ife->params, p, 1);
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if (exists)
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spin_unlock_bh(&ife->tcf_lock);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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if (p)
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kfree_rcu(p, rcu);
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@ -603,6 +603,13 @@ metadata_parse_err:
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tcf_idr_insert(tn, *a);
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return ret;
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metadata_parse_err:
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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release_idr:
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kfree(p);
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tcf_idr_release(*a, bind);
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return err;
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}
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static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
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@ -1060,5 +1060,30 @@
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"matchPattern": "action order [0-9]*: ife encode action pipe.*allow prio.*index 4",
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"matchCount": "0",
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"teardown": []
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},
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{
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"id": "a0e2",
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"name": "Replace ife encode action with invalid goto chain control",
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"category": [
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"actions",
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"ife"
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],
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"setup": [
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[
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"$TC actions flush action ife",
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0,
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1,
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255
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],
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"$TC actions add action ife encode allow mark pass index 90"
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],
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"cmdUnderTest": "$TC actions replace action ife encode allow mark goto chain 42 index 90 cookie c1a0c1a0",
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"expExitCode": "255",
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"verifyCmd": "$TC actions get action ife index 90",
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"matchPattern": "action order [0-9]*: ife encode action pass.*type 0[xX]ED3E .*allow mark.*index 90 ref",
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"matchCount": "1",
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"teardown": [
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"$TC actions flush action ife"
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]
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}
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]
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