[PATCH net 0/2] net_sched: Fix two tc_index filter init issues

[PATCH net 0/2] net_sched: Fix two tc_index filter init issues

[Hangbin Liu]

These two patches fix two tc_index filter init issues. The first one fixes
missing exts info in new filter, which will cause NULL pointer dereference
when delete tcindex filter. The second one fixes missing res info when create
new filter, which will make filter unbind failed.

Hangbin Liu (2):
  net_sched: fix NULL pointer dereference when delete tcindex filter
  net_sched: Fix missing res info when create new filter

 net/sched/cls_tcindex.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

-- 
2.5.5

[PATCH net 1/2] net_sched: fix NULL pointer dereference when delete tcindex filter

[Hangbin Liu]

Li Shuang reported the following crash:

[   71.267724] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
[   71.276456] PGD 800000085d9bd067 P4D 800000085d9bd067 PUD 859a0b067 PMD 0
[   71.284127] Oops: 0000 [#1] SMP PTI
[   71.288015] CPU: 12 PID: 2386 Comm: tc Not tainted 4.18.0-rc8.latest+ #131
[   71.295686] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.1.5 04/11/2016
[   71.304037] RIP: 0010:tcindex_delete+0x72/0x280 [cls_tcindex]
[   71.310446] Code: 00 31 f6 48 87 75 20 48 85 f6 74 11 48 8b 47 18 48 8b 40 08 48 8b 40 50 e8 fb a6 f8 fc 48 85 db 0f 84 dc 00 00 00 48 8b 73 18 <8b> 56 04 48 8d 7e 04 85 d2 0f 84 7b 01 00
[   71.331517] RSP: 0018:ffffb45207b3f898 EFLAGS: 00010282
[   71.337345] RAX: ffff8ad3d72d6360 RBX: ffff8acc84393680 RCX: 000000000000002e
[   71.345306] RDX: ffff8ad3d72c8570 RSI: 0000000000000000 RDI: ffff8ad847a45800
[   71.353277] RBP: ffff8acc84393688 R08: ffff8ad3d72c8400 R09: 0000000000000000
[   71.361238] R10: ffff8ad3de786e00 R11: 0000000000000000 R12: ffffb45207b3f8c7
[   71.369199] R13: ffff8ad3d93bd2a0 R14: 000000000000002e R15: ffff8ad3d72c9600
[   71.377161] FS:  00007f9d3ec3e740(0000) GS:ffff8ad3df980000(0000) knlGS:0000000000000000
[   71.386188] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   71.392597] CR2: 0000000000000004 CR3: 0000000852f06003 CR4: 00000000001606e0
[   71.400558] Call Trace:
[   71.403299]  tcindex_destroy_element+0x25/0x40 [cls_tcindex]
[   71.409611]  tcindex_walk+0xbb/0x110 [cls_tcindex]
[   71.414953]  tcindex_destroy+0x44/0x90 [cls_tcindex]
[   71.420492]  ? tcindex_delete+0x280/0x280 [cls_tcindex]
[   71.426323]  tcf_proto_destroy+0x16/0x40
[   71.430696]  tcf_chain_flush+0x51/0x70
[   71.434876]  tcf_block_put_ext.part.30+0x8f/0x1b0
[   71.440122]  tcf_block_put+0x4d/0x70
[   71.444108]  cbq_destroy+0x4d/0xd0 [sch_cbq]
[   71.448869]  qdisc_destroy+0x62/0x130
[   71.452951]  dsmark_destroy+0x2a/0x70 [sch_dsmark]
[   71.458300]  qdisc_destroy+0x62/0x130
[   71.462373]  qdisc_graft+0x3ba/0x470
[   71.466359]  tc_get_qdisc+0x2a6/0x2c0
[   71.470443]  ? cred_has_capability+0x7d/0x130
[   71.475307]  rtnetlink_rcv_msg+0x263/0x2d0
[   71.479875]  ? rtnl_calcit.isra.30+0x110/0x110
[   71.484832]  netlink_rcv_skb+0x4d/0x130
[   71.489109]  netlink_unicast+0x1a3/0x250
[   71.493482]  netlink_sendmsg+0x2ae/0x3a0
[   71.497859]  sock_sendmsg+0x36/0x40
[   71.501748]  ___sys_sendmsg+0x26f/0x2d0
[   71.506029]  ? handle_pte_fault+0x586/0xdf0
[   71.510694]  ? __handle_mm_fault+0x389/0x500
[   71.515457]  ? __sys_sendmsg+0x5e/0xa0
[   71.519636]  __sys_sendmsg+0x5e/0xa0
[   71.523626]  do_syscall_64+0x5b/0x180
[   71.527711]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   71.533345] RIP: 0033:0x7f9d3e257f10
[   71.537331] Code: c3 48 8b 05 82 6f 2c 00 f7 db 64 89 18 48 83 cb ff eb dd 0f 1f 80 00 00 00 00 83 3d 8d d0 2c 00 00 75 10 b8 2e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8
[   71.558401] RSP: 002b:00007fff6f893398 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   71.566848] RAX: ffffffffffffffda RBX: 000000005b71274d RCX: 00007f9d3e257f10
[   71.574810] RDX: 0000000000000000 RSI: 00007fff6f8933e0 RDI: 0000000000000003
[   71.582770] RBP: 00007fff6f8933e0 R08: 000000000000ffff R09: 0000000000000003
[   71.590729] R10: 00007fff6f892e20 R11: 0000000000000246 R12: 0000000000000000
[   71.598689] R13: 0000000000662ee0 R14: 0000000000000000 R15: 0000000000000000
[   71.606651] Modules linked in: sch_cbq cls_tcindex sch_dsmark xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_coni
[   71.685425]  libahci i2c_algo_bit i2c_core i40e libata dca mdio megaraid_sas dm_mirror dm_region_hash dm_log dm_mod
[   71.697075] CR2: 0000000000000004
[   71.700792] ---[ end trace f604eb1acacd978b ]---

Reproducer:
tc qdisc add dev lo handle 1:0 root dsmark indices 64 set_tc_index
tc filter add dev lo parent 1:0 protocol ip prio 1 tcindex mask 0xfc shift 2
tc qdisc add dev lo parent 1:0 handle 2:0 cbq bandwidth 10Mbit cell 8 avpkt 1000 mpu 64
tc class add dev lo parent 2:0 classid 2:1 cbq bandwidth 10Mbit rate 1500Kbit avpkt 1000 prio 1 bounded isolated allot 1514 weight 1 maxburst 10
tc filter add dev lo parent 2:0 protocol ip prio 1 handle 0x2e tcindex classid 2:1 pass_on
tc qdisc add dev lo parent 2:1 pfifo limit 5
tc qdisc del dev lo root

This is because in tcindex_set_parms, when there is no old_r, we set new
exts to cr.exts. And we didn't set it to filter when r == &new_filter_result.

Then in tcindex_delete() -> tcf_exts_get_net(), we will get NULL pointer
dereference as we didn't init exts.

Fix it by moving tcf_exts_change() after "if (old_r && old_r != r)" check.
Then we don't need "cr" as there is no errout after that.

Fixes: bf63ac73b3e13 ("net_sched: fix an oops in tcindex filter")
Reported-by: Li Shuang <shuali@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 net/sched/cls_tcindex.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 32f4bbd..ddaa4e6 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -447,11 +447,6 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		tcf_bind_filter(tp, &cr.res, base);
 	}
 
-	if (old_r)
-		tcf_exts_change(&r->exts, &e);
-	else
-		tcf_exts_change(&cr.exts, &e);
-
 	if (old_r && old_r != r) {
 		err = tcindex_filter_result_init(old_r);
 		if (err < 0) {
@@ -462,6 +457,8 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 
 	oldp = p;
 	r->res = cr.res;
+	tcf_exts_change(&r->exts, &e);
+
 	rcu_assign_pointer(tp->root, cp);
 
 	if (r == &new_filter_result) {
-- 
2.5.5

[PATCH net 2/2] net_sched: Fix missing res info when create new tc_index filter

[Hangbin Liu]

Li Shuang reported the following warn:

[  733.484610] WARNING: CPU: 6 PID: 21123 at net/sched/sch_cbq.c:1418 cbq_destroy_class+0x5d/0x70 [sch_cbq]
[  733.495190] Modules linked in: sch_cbq cls_tcindex sch_dsmark rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat l
[  733.574155]  syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm igb ixgbe ahci libahci i2c_algo_bit libata i40e i2c_core dca mdio megaraid_sas dm_mirror dm_region_hash dm_log dm_mod
[  733.592500] CPU: 6 PID: 21123 Comm: tc Not tainted 4.18.0-rc8.latest+ #131
[  733.600169] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.1.5 04/11/2016
[  733.608518] RIP: 0010:cbq_destroy_class+0x5d/0x70 [sch_cbq]
[  733.614734] Code: e7 d9 d2 48 8b 7b 48 e8 61 05 da d2 48 8d bb f8 00 00 00 e8 75 ae d5 d2 48 39 eb 74 0a 48 89 df 5b 5d e9 16 6c 94 d2 5b 5d c3 <0f> 0b eb b6 0f 1f 44 00 00 66 2e 0f 1f 84
[  733.635798] RSP: 0018:ffffbfbb066bb9d8 EFLAGS: 00010202
[  733.641627] RAX: 0000000000000001 RBX: ffff9cdd17392800 RCX: 000000008010000f
[  733.649588] RDX: ffff9cdd1df547e0 RSI: ffff9cdd17392800 RDI: ffff9cdd0f84c800
[  733.657547] RBP: ffff9cdd0f84c800 R08: 0000000000000001 R09: 0000000000000000
[  733.665508] R10: ffff9cdd0f84d000 R11: 0000000000000001 R12: 0000000000000001
[  733.673469] R13: 0000000000000000 R14: 0000000000000001 R15: ffff9cdd17392200
[  733.681430] FS:  00007f911890a740(0000) GS:ffff9cdd1f8c0000(0000) knlGS:0000000000000000
[  733.690456] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  733.696864] CR2: 0000000000b5544c CR3: 0000000859374002 CR4: 00000000001606e0
[  733.704826] Call Trace:
[  733.707554]  cbq_destroy+0xa1/0xd0 [sch_cbq]
[  733.712318]  qdisc_destroy+0x62/0x130
[  733.716401]  dsmark_destroy+0x2a/0x70 [sch_dsmark]
[  733.721745]  qdisc_destroy+0x62/0x130
[  733.725829]  qdisc_graft+0x3ba/0x470
[  733.729817]  tc_get_qdisc+0x2a6/0x2c0
[  733.733901]  ? cred_has_capability+0x7d/0x130
[  733.738761]  rtnetlink_rcv_msg+0x263/0x2d0
[  733.743330]  ? rtnl_calcit.isra.30+0x110/0x110
[  733.748287]  netlink_rcv_skb+0x4d/0x130
[  733.752576]  netlink_unicast+0x1a3/0x250
[  733.756949]  netlink_sendmsg+0x2ae/0x3a0
[  733.761324]  sock_sendmsg+0x36/0x40
[  733.765213]  ___sys_sendmsg+0x26f/0x2d0
[  733.769493]  ? handle_pte_fault+0x586/0xdf0
[  733.774158]  ? __handle_mm_fault+0x389/0x500
[  733.778919]  ? __sys_sendmsg+0x5e/0xa0
[  733.783099]  __sys_sendmsg+0x5e/0xa0
[  733.787087]  do_syscall_64+0x5b/0x180
[  733.791171]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  733.796805] RIP: 0033:0x7f9117f23f10
[  733.800791] Code: c3 48 8b 05 82 6f 2c 00 f7 db 64 89 18 48 83 cb ff eb dd 0f 1f 80 00 00 00 00 83 3d 8d d0 2c 00 00 75 10 b8 2e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8
[  733.821873] RSP: 002b:00007ffe96818398 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  733.830319] RAX: ffffffffffffffda RBX: 000000005b71244c RCX: 00007f9117f23f10
[  733.838280] RDX: 0000000000000000 RSI: 00007ffe968183e0 RDI: 0000000000000003
[  733.846241] RBP: 00007ffe968183e0 R08: 000000000000ffff R09: 0000000000000003
[  733.854202] R10: 00007ffe96817e20 R11: 0000000000000246 R12: 0000000000000000
[  733.862161] R13: 0000000000662ee0 R14: 0000000000000000 R15: 0000000000000000
[  733.870121] ---[ end trace 28edd4aad712ddca ]---

This is because we didn't update f->result.res when create new filter. Then in
tcindex_delete() -> tcf_unbind_filter(), we will failed to find out the res
and unbind filter, which will trigger the WARN_ON() in cbq_destroy_class().

Fix it by updating f->result.res when create new filter.

Fixes: 6e0565697a106 ("net_sched: fix another crash in cls_tcindex")
Reported-by: Li Shuang <shuali@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 net/sched/cls_tcindex.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index ddaa4e6..9ccc93f 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -465,6 +465,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		struct tcindex_filter *nfp;
 		struct tcindex_filter __rcu **fp;
 
+		f->result.res = r->res;
 		tcf_exts_change(&f->result.exts, &r->exts);
 
 		fp = cp->h + (handle % cp->hash);
-- 
2.5.5

Re: [PATCH net 1/2] net_sched: fix NULL pointer dereference when delete tcindex filter

[Cong Wang]

On Mon, Aug 13, 2018 at 3:44 AM Hangbin Liu <liuhangbin@gmail.com> wrote:
>
> This is because in tcindex_set_parms, when there is no old_r, we set new
> exts to cr.exts. And we didn't set it to filter when r == &new_filter_result.
>
> Then in tcindex_delete() -> tcf_exts_get_net(), we will get NULL pointer
> dereference as we didn't init exts.
>
> Fix it by moving tcf_exts_change() after "if (old_r && old_r != r)" check.
> Then we don't need "cr" as there is no errout after that.

Acked-by: Cong Wang <xiyou.wangcong@gmail.com>

Re: [PATCH net 2/2] net_sched: Fix missing res info when create new tc_index filter

[Cong Wang]

On Mon, Aug 13, 2018 at 3:44 AM Hangbin Liu <liuhangbin@gmail.com> wrote:
> This is because we didn't update f->result.res when create new filter. Then in
> tcindex_delete() -> tcf_unbind_filter(), we will failed to find out the res
> and unbind filter, which will trigger the WARN_ON() in cbq_destroy_class().
>
> Fix it by updating f->result.res when create new filter.
>
> Fixes: 6e0565697a106 ("net_sched: fix another crash in cls_tcindex")
> Reported-by: Li Shuang <shuali@redhat.com>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

Acked-by: Cong Wang <xiyou.wangcong@gmail.com>

Re: [PATCH net 0/2] net_sched: Fix two tc_index filter init issues

[David Miller]

From: Hangbin Liu <liuhangbin@gmail.com>
Date: Mon, 13 Aug 2018 18:44:02 +0800

> These two patches fix two tc_index filter init issues. The first one fixes
> missing exts info in new filter, which will cause NULL pointer dereference
> when delete tcindex filter. The second one fixes missing res info when create
> new filter, which will make filter unbind failed.

Series applied and queued up for -stable, thanks.