Subject: CVE-2021-47139: net: hns3: put off calling register_netdev() until client initialize complete

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

net: hns3: put off calling register_netdev() until client initialize complete

Currently, the netdevice is registered before client initializing
complete. So there is a timewindow between netdevice available
and usable. In this case, if user try to change the channel number
or ring param, it may cause the hns3_set_rx_cpu_rmap() being called
twice, and report bug.

[47199.416502] hns3 0000:35:00.0 eth1: set channels: tqp_num=1, rxfh=0
[47199.430340] hns3 0000:35:00.0 eth1: already uninitialized
[47199.438554] hns3 0000:35:00.0: rss changes from 4 to 1
[47199.511854] hns3 0000:35:00.0: Channels changed, rss_size from 4 to 1, tqps from 4 to 1
[47200.163524] ------------[ cut here ]------------
[47200.171674] kernel BUG at lib/cpu_rmap.c:142!
[47200.177847] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[47200.185259] Modules linked in: hclge(+) hns3(-) hns3_cae(O) hns_roce_hw_v2 hnae3 vfio_iommu_type1 vfio_pci vfio_virqfd vfio pv680_mii(O) [last unloaded: hclge]
[47200.205912] CPU: 1 PID: 8260 Comm: ethtool Tainted: G           O      5.11.0-rc3+ #1
[47200.215601] Hardware name:  , xxxxxx 02/04/2021
[47200.223052] pstate: 60400009 (nZCv daif +PAN -UAO -TCO BTYPE=--)
[47200.230188] pc : cpu_rmap_add+0x38/0x40
[47200.237472] lr : irq_cpu_rmap_add+0x84/0x140
[47200.243291] sp : ffff800010e93a30
[47200.247295] x29: ffff800010e93a30 x28: ffff082100584880
[47200.254155] x27: 0000000000000000 x26: 0000000000000000
[47200.260712] x25: 0000000000000000 x24: 0000000000000004
[47200.267241] x23: ffff08209ba03000 x22: ffff08209ba038c0
[47200.273789] x21: 000000000000003f x20: ffff0820e2bc1680
[47200.280400] x19: ffff0820c970ec80 x18: 00000000000000c0
[47200.286944] x17: 0000000000000000 x16: ffffb43debe4a0d0
[47200.293456] x15: fffffc2082990600 x14: dead000000000122
[47200.300059] x13: ffffffffffffffff x12: 000000000000003e
[47200.306606] x11: ffff0820815b8080 x10: ffff53e411988000
[47200.313171] x9 : 0000000000000000 x8 : ffff0820e2bc1700
[47200.319682] x7 : 0000000000000000 x6 : 000000000000003f
[47200.326170] x5 : 0000000000000040 x4 : ffff800010e93a20
[47200.332656] x3 : 0000000000000004 x2 : ffff0820c970ec80
[47200.339168] x1 : ffff0820e2bc1680 x0 : 0000000000000004
[47200.346058] Call trace:
[47200.349324]  cpu_rmap_add+0x38/0x40
[47200.354300]  hns3_set_rx_cpu_rmap+0x6c/0xe0 [hns3]
[47200.362294]  hns3_reset_notify_init_enet+0x1cc/0x340 [hns3]
[47200.370049]  hns3_change_channels+0x40/0xb0 [hns3]
[47200.376770]  hns3_set_channels+0x12c/0x2a0 [hns3]
[47200.383353]  ethtool_set_channels+0x140/0x250
[47200.389772]  dev_ethtool+0x714/0x23d0
[47200.394440]  dev_ioctl+0x4cc/0x640
[47200.399277]  sock_do_ioctl+0x100/0x2a0
[47200.404574]  sock_ioctl+0x28c/0x470
[47200.409079]  __arm64_sys_ioctl+0xb4/0x100
[47200.415217]  el0_svc_common.constprop.0+0x84/0x210
[47200.422088]  do_el0_svc+0x28/0x34
[47200.426387]  el0_svc+0x28/0x70
[47200.431308]  el0_sync_handler+0x1a4/0x1b0
[47200.436477]  el0_sync+0x174/0x180
[47200.441562] Code: 11000405 79000c45 f8247861 d65f03c0 (d4210000)
[47200.448869] ---[ end trace a01efe4ce42e5f34 ]---

The process is like below:
excuting hns3_client_init
|
register_netdev()
|                           hns3_set_channels()
|                           |
hns3_set_rx_cpu_rmap()      hns3_reset_notify_uninit_enet()
|                               |
|                            quit without calling function
|                            hns3_free_rx_cpu_rmap for flag
|                            HNS3_NIC_STATE_INITED is unset.
|                           |
|                           hns3_reset_notify_init_enet()
|                               |
set HNS3_NIC_STATE_INITED    call hns3_set_rx_cpu_rmap()-- crash

Fix it by calling register_netdev() at the end of function
hns3_client_init().

The Linux kernel CVE team has assigned CVE-2021-47139 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.6 with commit 08a100689d4b and fixed in 5.10.42 with commit a663c1e418a3
	Issue introduced in 5.6 with commit 08a100689d4b and fixed in 5.12.9 with commit 0921a0620b50
	Issue introduced in 5.6 with commit 08a100689d4b and fixed in 5.13 with commit a289a7e5c1d4

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47139
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/a663c1e418a3b5b8e8edfad4bc8e7278c312d6fc
	https://git.kernel.org/stable/c/0921a0620b5077796fddffb22a8e6bc635a4bb50
	https://git.kernel.org/stable/c/a289a7e5c1d49b7d47df9913c1cc81fb48fab613