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Message-Id: <20200420132940.21627-1-ap420073@gmail.com>
Date: Mon, 20 Apr 2020 13:29:40 +0000
From: Taehee Yoo <ap420073@...il.com>
To: davem@...emloft.net, kuba@...nel.org, dingtianhong@...wei.com,
netdev@...r.kernel.org
Cc: ap420073@...il.com
Subject: [PATCH net] macvlan: fix null dereference in macvlan_device_event()
In the macvlan_device_event(), the list_first_entry_or_null() is used.
This function could return null pointer if there is no node.
But, the macvlan module doesn't check the null pointer.
So, null-ptr-deref would occur.
bond0
|
+----+-----+
| |
macvlan0 macvlan1
| |
dummy0 dummy1
The problem scenario.
If dummy1 is removed,
1. ->dellink() of dummy1 is called.
2. NETDEV_UNREGISTER of dummy1 notification is sent to macvlan module.
3. ->dellink() of macvlan1 is called.
4. NETDEV_UNREGISTER of macvlan1 notification is sent to bond module.
5. __bond_release_one() is called and it internally calls
dev_set_mac_address().
6. dev_set_mac_address() calls the ->ndo_set_mac_address() of macvlan1,
which is macvlan_set_mac_address().
7. macvlan_set_mac_address() calls the dev_set_mac_address() with dummy1.
8. NETDEV_CHANGEADDR of dummy1 is sent to macvlan module.
9. In the macvlan_device_event(), it calls list_first_entry_or_null().
At this point, dummy1 and macvlan1 were removed.
So, list_first_entry_or_null() will return NULL.
Test commands:
ip netns add nst
ip netns exec nst ip link add bond0 type bond
for i in {0..10}
do
ip netns exec nst ip link add dummy$i type dummy
ip netns exec nst ip link add macvlan$i link dummy$i \
type macvlan mode passthru
ip netns exec nst ip link set macvlan$i master bond0
done
ip netns del nst
Splat looks like:
[ 40.585687][ T146] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEI
[ 40.587249][ T146] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 40.588342][ T146] CPU: 1 PID: 146 Comm: kworker/u8:2 Not tainted 5.7.0-rc1+ #532
[ 40.589299][ T146] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 40.590469][ T146] Workqueue: netns cleanup_net
[ 40.591045][ T146] RIP: 0010:macvlan_device_event+0x4e2/0x900 [macvlan]
[ 40.591905][ T146] Code: 00 00 00 00 00 fc ff df 80 3c 06 00 0f 85 45 02 00 00 48 89 da 48 b8 00 00 00 00 00 fc ff d2
[ 40.594126][ T146] RSP: 0018:ffff88806116f4a0 EFLAGS: 00010246
[ 40.594783][ T146] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 40.595653][ T146] RDX: 0000000000000000 RSI: ffff88806547ddd8 RDI: ffff8880540f1360
[ 40.596495][ T146] RBP: ffff88804011a808 R08: fffffbfff4fb8421 R09: fffffbfff4fb8421
[ 40.597377][ T146] R10: ffffffffa7dc2107 R11: 0000000000000000 R12: 0000000000000008
[ 40.598186][ T146] R13: ffff88804011a000 R14: ffff8880540f1000 R15: 1ffff1100c22de9a
[ 40.599012][ T146] FS: 0000000000000000(0000) GS:ffff888067800000(0000) knlGS:0000000000000000
[ 40.600004][ T146] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 40.600665][ T146] CR2: 00005572d3a807b8 CR3: 000000005fcf4003 CR4: 00000000000606e0
[ 40.601485][ T146] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 40.602461][ T146] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 40.603443][ T146] Call Trace:
[ 40.603871][ T146] ? nf_tables_dump_setelem+0xa0/0xa0 [nf_tables]
[ 40.604587][ T146] ? macvlan_uninit+0x100/0x100 [macvlan]
[ 40.605212][ T146] ? __module_text_address+0x13/0x140
[ 40.605842][ T146] notifier_call_chain+0x90/0x160
[ 40.606477][ T146] dev_set_mac_address+0x28e/0x3f0
[ 40.607117][ T146] ? netdev_notify_peers+0xc0/0xc0
[ 40.607762][ T146] ? __module_text_address+0x13/0x140
[ 40.608440][ T146] ? notifier_call_chain+0x90/0x160
[ 40.609097][ T146] ? dev_set_mac_address+0x1f0/0x3f0
[ 40.609758][ T146] dev_set_mac_address+0x1f0/0x3f0
[ 40.610402][ T146] ? __local_bh_enable_ip+0xe9/0x1b0
[ 40.611071][ T146] ? bond_hw_addr_flush+0x77/0x100 [bonding]
[ 40.611823][ T146] ? netdev_notify_peers+0xc0/0xc0
[ 40.612461][ T146] ? bond_hw_addr_flush+0x77/0x100 [bonding]
[ 40.613213][ T146] ? bond_hw_addr_flush+0x77/0x100 [bonding]
[ 40.613963][ T146] ? __local_bh_enable_ip+0xe9/0x1b0
[ 40.614631][ T146] ? bond_time_in_interval.isra.31+0x90/0x90 [bonding]
[ 40.615484][ T146] ? __bond_release_one+0x9f0/0x12c0 [bonding]
[ 40.616230][ T146] __bond_release_one+0x9f0/0x12c0 [bonding]
[ 40.616949][ T146] ? bond_enslave+0x47c0/0x47c0 [bonding]
[ 40.617642][ T146] ? lock_downgrade+0x730/0x730
[ 40.618218][ T146] ? check_flags.part.42+0x450/0x450
[ 40.618850][ T146] ? __mutex_unlock_slowpath+0xd0/0x670
[ 40.619519][ T146] ? trace_hardirqs_on+0x30/0x180
[ 40.620117][ T146] ? wait_for_completion+0x250/0x250
[ 40.620754][ T146] bond_netdev_event+0x822/0x970 [bonding]
[ 40.621460][ T146] ? __module_text_address+0x13/0x140
[ 40.622097][ T146] notifier_call_chain+0x90/0x160
[ 40.622806][ T146] rollback_registered_many+0x660/0xcf0
[ 40.623522][ T146] ? netif_set_real_num_tx_queues+0x780/0x780
[ 40.624290][ T146] ? notifier_call_chain+0x90/0x160
[ 40.624957][ T146] ? netdev_upper_dev_unlink+0x114/0x180
[ 40.625686][ T146] ? __netdev_adjacent_dev_unlink_neighbour+0x30/0x30
[ 40.626421][ T146] ? mutex_is_locked+0x13/0x50
[ 40.627016][ T146] ? unregister_netdevice_queue+0xf2/0x240
[ 40.627663][ T146] unregister_netdevice_many.part.134+0x13/0x1b0
[ 40.628362][ T146] default_device_exit_batch+0x2d9/0x390
[ 40.628987][ T146] ? unregister_netdevice_many+0x40/0x40
[ 40.629615][ T146] ? dev_change_net_namespace+0xcb0/0xcb0
[ 40.630279][ T146] ? prepare_to_wait_exclusive+0x2e0/0x2e0
[ 40.630943][ T146] ? ops_exit_list.isra.9+0x97/0x140
[ 40.631554][ T146] cleanup_net+0x441/0x890
[ ... ]
Fixes: e289fd28176b ("macvlan: fix the problem when mac address changes for passthru mode")
Reported-by: syzbot+5035b1f9dc7ea4558d5a@...kaller.appspotmail.com
Signed-off-by: Taehee Yoo <ap420073@...il.com>
---
drivers/net/macvlan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index e7289d67268f..0482adc9916b 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1704,7 +1704,7 @@ static int macvlan_device_event(struct notifier_block *unused,
struct macvlan_dev,
list);
- if (macvlan_sync_address(vlan->dev, dev->dev_addr))
+ if (vlan && macvlan_sync_address(vlan->dev, dev->dev_addr))
return NOTIFY_BAD;
break;
--
2.17.1
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