From: Ziyang Xuan <william.xuanziyang@huawei.com>
Date: Mon, 18 Sep 2023 20:30:11 +0800
Subject: team: fix null-ptr-deref when team device type is changed
Patch-mainline: v6.6-rc3
Git-commit: 492032760127251e5540a5716a70996bacf2a3fd
References: bsc#1220870 CVE-2023-52574
Get a null-ptr-deref bug as follows with reproducer [1].
BUG: kernel NULL pointer dereference, address: 0000000000000228
...
RIP: 0010:vlan_dev_hard_header+0x35/0x140 [8021q]
...
Call Trace:
<TASK>
? __die+0x24/0x70
? page_fault_oops+0x82/0x150
? exc_page_fault+0x69/0x150
? asm_exc_page_fault+0x26/0x30
? vlan_dev_hard_header+0x35/0x140 [8021q]
? vlan_dev_hard_header+0x8e/0x140 [8021q]
neigh_connected_output+0xb2/0x100
ip6_finish_output2+0x1cb/0x520
? nf_hook_slow+0x43/0xc0
? ip6_mtu+0x46/0x80
ip6_finish_output+0x2a/0xb0
mld_sendpack+0x18f/0x250
mld_ifc_work+0x39/0x160
process_one_work+0x1e6/0x3f0
worker_thread+0x4d/0x2f0
? __pfx_worker_thread+0x10/0x10
kthread+0xe5/0x120
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
[1]
$ teamd -t team0 -d -c '{"runner": {"name": "loadbalance"}}'
$ ip link add name t-dummy type dummy
$ ip link add link t-dummy name t-dummy.100 type vlan id 100
$ ip link add name t-nlmon type nlmon
$ ip link set t-nlmon master team0
$ ip link set t-nlmon nomaster
$ ip link set t-dummy up
$ ip link set team0 up
$ ip link set t-dummy.100 down
$ ip link set t-dummy.100 master team0
When enslave a vlan device to team device and team device type is changed
from non-ether to ether, header_ops of team device is changed to
vlan_header_ops. That is incorrect and will trigger null-ptr-deref
for vlan->real_dev in vlan_dev_hard_header() because team device is not
a vlan device.
Cache eth_header_ops in team_setup(), then assign cached header_ops to
header_ops of team net device when its type is changed from non-ether
to ether to fix the bug.
Fixes: 1d76efe1577b ("team: add support for non-ethernet devices")
Suggested-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230918123011.1884401-1-william.xuanziyang@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/team/team.c | 10 +++++++++-
include/linux/if_team.h | 2 ++
2 files changed, 11 insertions(+), 1 deletion(-)
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -2085,7 +2085,12 @@ static const struct ethtool_ops team_eth
static void team_setup_by_port(struct net_device *dev,
struct net_device *port_dev)
{
- dev->header_ops = port_dev->header_ops;
+ struct team *team = netdev_priv(dev);
+
+ if (port_dev->type == ARPHRD_ETHER)
+ dev->header_ops = team->header_ops_cache;
+ else
+ dev->header_ops = port_dev->header_ops;
dev->type = port_dev->type;
dev->hard_header_len = port_dev->hard_header_len;
dev->needed_headroom = port_dev->needed_headroom;
@@ -2114,8 +2119,11 @@ static int team_dev_type_check_change(st
static void team_setup(struct net_device *dev)
{
+ struct team *team = netdev_priv(dev);
+
ether_setup(dev);
dev->max_mtu = ETH_MAX_MTU;
+ team->header_ops_cache = dev->header_ops;
dev->netdev_ops = &team_netdev_ops;
dev->ethtool_ops = &team_ethtool_ops;
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -178,6 +178,8 @@ struct team {
struct net_device *dev; /* associated netdevice */
struct team_pcpu_stats __percpu *pcpu_stats;
+ const struct header_ops *header_ops_cache;
+
struct mutex lock; /* used for overall locking, e.g. port lists write */
/*