On Wed 27 Feb 2019 at 17:40, Davide Caratti <dcara...@redhat.com> wrote:
> 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 <dcara...@redhat.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);
>
oldchain is not released before return.
> 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"
> + ]
> }
> ]
