From: Taehee Yoo ap420073@gmail.com
[ Upstream commit 4dee15b4fd0d61ec6bbd179238191e959d34cf7a ]
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@syzkaller.appspotmail.com Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 84767722065a8..d5d4d109ee106 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -1561,7 +1561,7 @@ 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;