4.19-stable review patch. If anyone has any objections, please let me know.
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From: Ziyang Xuan william.xuanziyang@huawei.com
[ Upstream commit 492032760127251e5540a5716a70996bacf2a3fd ]
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... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/team/team.c | 10 +++++++++- include/linux/if_team.h | 2 ++ 2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c index 8b5e1ec6aabfb..08f9530fd5b15 100644 --- a/drivers/net/team/team.c +++ b/drivers/net/team/team.c @@ -2095,7 +2095,12 @@ static const struct ethtool_ops team_ethtool_ops = { 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; @@ -2142,8 +2147,11 @@ static int team_dev_type_check_change(struct net_device *dev,
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; diff --git a/include/linux/if_team.h b/include/linux/if_team.h index ac42da56f7a28..fd32538ae705e 100644 --- a/include/linux/if_team.h +++ b/include/linux/if_team.h @@ -196,6 +196,8 @@ 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 */
/*