[PATCH 4.14 129/138] net/sched: fix NULL dereference in the error path of tunnel_key_init()

From: Greg Kroah-Hartman
Date: Tue Apr 10 2018 - 18:40:13 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Davide Caratti <dcaratti@xxxxxxxxxx>


[ Upstream commit abdadd3cfd3e7ea3da61ac774f84777d1f702058 ]

when the following command

# tc action add action tunnel_key unset index 100

is run for the first time, and tunnel_key_init() fails to allocate struct
tcf_tunnel_key_params, tunnel_key_release() dereferences NULL pointers.
This causes the following error:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: tunnel_key_release+0xd/0x40 [act_tunnel_key]
PGD 8000000033787067 P4D 8000000033787067 PUD 74646067 PMD 0
Oops: 0000 [#1] SMP PTI
Modules linked in: act_tunnel_key(E) act_csum ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache jbd2 crct10dif_pclmul crc32_pclmul snd_hda_codec_generic ghash_clmulni_intel snd_hda_intel pcbc snd_hda_codec snd_hda_core snd_hwdep snd_seq aesni_intel snd_seq_device crypto_simd glue_helper snd_pcm cryptd joydev snd_timer pcspkr virtio_balloon snd i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm virtio_net virtio_blk drm virtio_console crc32c_intel ata_piix serio_raw i2c_core virtio_pci libata virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
CPU: 2 PID: 3101 Comm: tc Tainted: G E 4.16.0-rc4.act_vlan.orig+ #403
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:tunnel_key_release+0xd/0x40 [act_tunnel_key]
RSP: 0018:ffffba46803b7768 EFLAGS: 00010286
RAX: ffffffffc09010a0 RBX: 0000000000000000 RCX: 0000000000000024
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff99ee336d7480
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
R10: 0000000000000220 R11: ffff99ee79d73131 R12: 0000000000000000
R13: ffff99ee32d67610 R14: ffff99ee7671dc38 R15: 00000000fffffff4
FS: 00007febcb2cd740(0000) GS:ffff99ee7fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 000000007c8e4005 CR4: 00000000001606e0
Call Trace:
__tcf_idr_release+0x79/0xf0
tunnel_key_init+0xd9/0x460 [act_tunnel_key]
tcf_action_init_1+0x2cc/0x430
tcf_action_init+0xd3/0x1b0
tc_ctl_action+0x18b/0x240
rtnetlink_rcv_msg+0x29c/0x310
? _cond_resched+0x15/0x30
? __kmalloc_node_track_caller+0x1b9/0x270
? rtnl_calcit.isra.28+0x100/0x100
netlink_rcv_skb+0xd2/0x110
netlink_unicast+0x17c/0x230
netlink_sendmsg+0x2cd/0x3c0
sock_sendmsg+0x30/0x40
___sys_sendmsg+0x27a/0x290
__sys_sendmsg+0x51/0x90
do_syscall_64+0x6e/0x1a0
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7febca6deba0
RSP: 002b:00007ffe7b0dd128 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffe7b0dd250 RCX: 00007febca6deba0
RDX: 0000000000000000 RSI: 00007ffe7b0dd1a0 RDI: 0000000000000003
RBP: 000000005aaa90cb R08: 0000000000000002 R09: 0000000000000000
R10: 00007ffe7b0dcba0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe7b0dd264 R14: 0000000000000001 R15: 0000000000669f60
Code: 44 00 00 8b 0d b5 23 00 00 48 8b 87 48 10 00 00 48 8b 3c c8 e9 a5 e5 d8 c3 0f 1f 44 00 00 0f 1f 44 00 00 53 48 8b 9f b0 00 00 00 <83> 7b 10 01 74 0b 48 89 df 31 f6 5b e9 f2 fa 7f c3 48 8b 7b 18
RIP: tunnel_key_release+0xd/0x40 [act_tunnel_key] RSP: ffffba46803b7768
CR2: 0000000000000010

Fix this in tunnel_key_release(), ensuring 'param' is not NULL before
dereferencing it.

Fixes: d0f6dd8a914f ("net/sched: Introduce act_tunnel_key")
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
Acked-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sched/act_tunnel_key.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -208,11 +208,12 @@ static void tunnel_key_release(struct tc
struct tcf_tunnel_key_params *params;

params = rcu_dereference_protected(t->params, 1);
+ if (params) {
+ if (params->tcft_action == TCA_TUNNEL_KEY_ACT_SET)
+ dst_release(&params->tcft_enc_metadata->dst);

- if (params->tcft_action == TCA_TUNNEL_KEY_ACT_SET)
- dst_release(&params->tcft_enc_metadata->dst);
-
- kfree_rcu(params, rcu);
+ kfree_rcu(params, rcu);
+ }
}

static int tunnel_key_dump_addresses(struct sk_buff *skb,