[PATCH 5.6 149/177] xfrm interface: fix oops when deleting a x-netns interface

From: Greg Kroah-Hartman
Date: Mon Jun 01 2020 - 14:19:37 EST


From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>

commit c95c5f58b35ef995f66cb55547eee6093ab5fcb8 upstream.

Here is the steps to reproduce the problem:
ip netns add foo
ip netns add bar
ip -n foo link add xfrmi0 type xfrm dev lo if_id 42
ip -n foo link set xfrmi0 netns bar
ip netns del foo
ip netns del bar

Which results to:
[ 186.686395] general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6bd3: 0000 [#1] SMP PTI
[ 186.687665] CPU: 7 PID: 232 Comm: kworker/u16:2 Not tainted 5.6.0+ #1
[ 186.688430] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 186.689420] Workqueue: netns cleanup_net
[ 186.689903] RIP: 0010:xfrmi_dev_uninit+0x1b/0x4b [xfrm_interface]
[ 186.690657] Code: 44 f6 ff ff 31 c0 5b 5d 41 5c 41 5d 41 5e c3 48 8d 8f c0 08 00 00 8b 05 ce 14 00 00 48 8b 97 d0 08 00 00 48 8b 92 c0 0e 00 00 <48> 8b 14 c2 48 8b 02 48 85 c0 74 19 48 39 c1 75 0c 48 8b 87 c0 08
[ 186.692838] RSP: 0018:ffffc900003b7d68 EFLAGS: 00010286
[ 186.693435] RAX: 000000000000000d RBX: ffff8881b0f31000 RCX: ffff8881b0f318c0
[ 186.694334] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000246 RDI: ffff8881b0f31000
[ 186.695190] RBP: ffffc900003b7df0 R08: ffff888236c07740 R09: 0000000000000040
[ 186.696024] R10: ffffffff81fce1b8 R11: 0000000000000002 R12: ffffc900003b7d80
[ 186.696859] R13: ffff8881edcc6a40 R14: ffff8881a1b6e780 R15: ffffffff81ed47c8
[ 186.697738] FS: 0000000000000000(0000) GS:ffff888237dc0000(0000) knlGS:0000000000000000
[ 186.698705] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 186.699408] CR2: 00007f2129e93148 CR3: 0000000001e0a000 CR4: 00000000000006e0
[ 186.700221] Call Trace:
[ 186.700508] rollback_registered_many+0x32b/0x3fd
[ 186.701058] ? __rtnl_unlock+0x20/0x3d
[ 186.701494] ? arch_local_irq_save+0x11/0x17
[ 186.702012] unregister_netdevice_many+0x12/0x55
[ 186.702594] default_device_exit_batch+0x12b/0x150
[ 186.703160] ? prepare_to_wait_exclusive+0x60/0x60
[ 186.703719] cleanup_net+0x17d/0x234
[ 186.704138] process_one_work+0x196/0x2e8
[ 186.704652] worker_thread+0x1a4/0x249
[ 186.705087] ? cancel_delayed_work+0x92/0x92
[ 186.705620] kthread+0x105/0x10f
[ 186.706000] ? __kthread_bind_mask+0x57/0x57
[ 186.706501] ret_from_fork+0x35/0x40
[ 186.706978] Modules linked in: xfrm_interface nfsv3 nfs_acl auth_rpcgss nfsv4 nfs lockd grace fscache sunrpc button parport_pc parport serio_raw evdev pcspkr loop ext4 crc16 mbcache jbd2 crc32c_generic 8139too ide_cd_mod cdrom ide_gd_mod ata_generic ata_piix libata scsi_mod piix psmouse i2c_piix4 ide_core 8139cp i2c_core mii floppy
[ 186.710423] ---[ end trace 463bba18105537e5 ]---

The problem is that x-netns xfrm interface are not removed when the link
netns is removed. This causes later this oops when thoses interfaces are
removed.

Let's add a handler to remove all interfaces related to a netns when this
netns is removed.

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Reported-by: Christophe Gouault <christophe.gouault@xxxxxxxxx>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/xfrm/xfrm_interface.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -750,7 +750,28 @@ static struct rtnl_link_ops xfrmi_link_o
.get_link_net = xfrmi_get_link_net,
};

+static void __net_exit xfrmi_exit_batch_net(struct list_head *net_exit_list)
+{
+ struct net *net;
+ LIST_HEAD(list);
+
+ rtnl_lock();
+ list_for_each_entry(net, net_exit_list, exit_list) {
+ struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
+ struct xfrm_if __rcu **xip;
+ struct xfrm_if *xi;
+
+ for (xip = &xfrmn->xfrmi[0];
+ (xi = rtnl_dereference(*xip)) != NULL;
+ xip = &xi->next)
+ unregister_netdevice_queue(xi->dev, &list);
+ }
+ unregister_netdevice_many(&list);
+ rtnl_unlock();
+}
+
static struct pernet_operations xfrmi_net_ops = {
+ .exit_batch = xfrmi_exit_batch_net,
.id = &xfrmi_net_id,
.size = sizeof(struct xfrmi_net),
};