During ice_sriov_configure, if num_vfs is 0, we are being asked by the
kernel to remove all VFs.

The driver first de-initializes the snapshot before freeing all the VFs.
This results in a use-after-free BUG detected by KASAN. The bug occurs
because the snapshot can still be accessed until all VFs are removed.

Fix this by freeing all the VFs first before calling
ice_mbx_deinit_snapshot.

[  +0.032591] ==================================================================
[  +0.000021] BUG: KASAN: use-after-free in ice_mbx_vf_state_handler+0x1c3/0x410 [ice]
[  +0.000315] Write of size 28 at addr ffff889908eb6f28 by task kworker/55:2/1530996

[  +0.000029] CPU: 55 PID: 1530996 Comm: kworker/55:2 Kdump: loaded Tainted: G S        I       5.17.0-dirty #1
[  +0.000022] Hardware name: Dell Inc. PowerEdge R740/0923K0, BIOS 1.6.13 12/17/2018
[  +0.000013] Workqueue: ice ice_service_task [ice]
[  +0.000279] Call Trace:
[  +0.000012]  <TASK>
[  +0.000011]  dump_stack_lvl+0x33/0x42
[  +0.000030]  print_report.cold.13+0xb2/0x6b3
[  +0.000028]  ? ice_mbx_vf_state_handler+0x1c3/0x410 [ice]
[  +0.000295]  kasan_report+0xa5/0x120
[  +0.000026]  ? __switch_to_asm+0x21/0x70
[  +0.000024]  ? ice_mbx_vf_state_handler+0x1c3/0x410 [ice]
[  +0.000298]  kasan_check_range+0x183/0x1e0
[  +0.000019]  memset+0x1f/0x40
[  +0.000018]  ice_mbx_vf_state_handler+0x1c3/0x410 [ice]
[  +0.000304]  ? ice_conv_link_speed_to_virtchnl+0x160/0x160 [ice]
[  +0.000297]  ? ice_vsi_dis_spoofchk+0x40/0x40 [ice]
[  +0.000305]  ice_is_malicious_vf+0x1aa/0x250 [ice]
[  +0.000303]  ? ice_restore_all_vfs_msi_state+0x160/0x160 [ice]
[  +0.000297]  ? __mutex_unlock_slowpath.isra.15+0x410/0x410
[  +0.000022]  ? ice_debug_cq+0xb7/0x230 [ice]
[  +0.000273]  ? __kasan_slab_alloc+0x2f/0x90
[  +0.000022]  ? memset+0x1f/0x40
[  +0.000017]  ? do_raw_spin_lock+0x119/0x1d0
[  +0.000022]  ? rwlock_bug.part.2+0x60/0x60
[  +0.000024]  __ice_clean_ctrlq+0x3a6/0xd60 [ice]
[  +0.000273]  ? newidle_balance+0x5b1/0x700
[  +0.000026]  ? ice_print_link_msg+0x2f0/0x2f0 [ice]
[  +0.000271]  ? update_cfs_group+0x1b/0x140
[  +0.000018]  ? load_balance+0x1260/0x1260
[  +0.000022]  ? ice_process_vflr_event+0x27/0x130 [ice]
[  +0.000301]  ice_service_task+0x136e/0x1470 [ice]
[  +0.000281]  process_one_work+0x3b4/0x6c0
[  +0.000030]  worker_thread+0x65/0x660
[  +0.000023]  ? __kthread_parkme+0xe4/0x100
[  +0.000021]  ? process_one_work+0x6c0/0x6c0
[  +0.000020]  kthread+0x179/0x1b0
[  +0.000018]  ? kthread_complete_and_exit+0x20/0x20
[  +0.000022]  ret_from_fork+0x22/0x30
[  +0.000026]  </TASK>

[  +0.000018] Allocated by task 10742:
[  +0.000013]  kasan_save_stack+0x1c/0x40
[  +0.000018]  __kasan_kmalloc+0x84/0xa0
[  +0.000016]  kmem_cache_alloc_trace+0x16c/0x2e0
[  +0.000015]  intel_iommu_probe_device+0xeb/0x860
[  +0.000015]  __iommu_probe_device+0x9a/0x2f0
[  +0.000016]  iommu_probe_device+0x43/0x270
[  +0.000015]  iommu_bus_notifier+0xa7/0xd0
[  +0.000015]  blocking_notifier_call_chain+0x90/0xc0
[  +0.000017]  device_add+0x5f3/0xd70
[  +0.000014]  pci_device_add+0x404/0xa40
[  +0.000015]  pci_iov_add_virtfn+0x3b0/0x550
[  +0.000016]  sriov_enable+0x3bb/0x600
[  +0.000013]  ice_ena_vfs+0x113/0xa79 [ice]
[  +0.000293]  ice_sriov_configure.cold.17+0x21/0xe0 [ice]
[  +0.000291]  sriov_numvfs_store+0x160/0x200
[  +0.000015]  kernfs_fop_write_iter+0x1db/0x270
[  +0.000018]  new_sync_write+0x21d/0x330
[  +0.000013]  vfs_write+0x376/0x410
[  +0.000013]  ksys_write+0xba/0x150
[  +0.000012]  do_syscall_64+0x3a/0x80
[  +0.000012]  entry_SYSCALL_64_after_hwframe+0x44/0xae

[  +0.000028] Freed by task 10742:
[  +0.000011]  kasan_save_stack+0x1c/0x40
[  +0.000015]  kasan_set_track+0x21/0x30
[  +0.000016]  kasan_set_free_info+0x20/0x30
[  +0.000012]  __kasan_slab_free+0x104/0x170
[  +0.000016]  kfree+0x9b/0x470
[  +0.000013]  devres_destroy+0x1c/0x20
[  +0.000015]  devm_kfree+0x33/0x40
[  +0.000012]  ice_mbx_deinit_snapshot+0x39/0x70 [ice]
[  +0.000295]  ice_sriov_configure+0xb0/0x260 [ice]
[  +0.000295]  sriov_numvfs_store+0x1bc/0x200
[  +0.000015]  kernfs_fop_write_iter+0x1db/0x270
[  +0.000016]  new_sync_write+0x21d/0x330
[  +0.000012]  vfs_write+0x376/0x410
[  +0.000012]  ksys_write+0xba/0x150
[  +0.000012]  do_syscall_64+0x3a/0x80
[  +0.000012]  entry_SYSCALL_64_after_hwframe+0x44/0xae

[  +0.000024] Last potentially related work creation:
[  +0.000010]  kasan_save_stack+0x1c/0x40
[  +0.000016]  __kasan_record_aux_stack+0x98/0xa0
[  +0.000013]  insert_work+0x34/0x160
[  +0.000015]  __queue_work+0x20e/0x650
[  +0.000016]  queue_work_on+0x4c/0x60
[  +0.000015]  nf_nat_masq_schedule+0x297/0x2e0 [nf_nat]
[  +0.000034]  masq_device_event+0x5a/0x60 [nf_nat]
[  +0.000031]  raw_notifier_call_chain+0x5f/0x80
[  +0.000017]  dev_close_many+0x1d6/0x2c0
[  +0.000015]  unregister_netdevice_many+0x4e3/0xa30
[  +0.000015]  unregister_netdevice_queue+0x192/0x1d0
[  +0.000014]  iavf_remove+0x8f9/0x930 [iavf]
[  +0.000058]  pci_device_remove+0x65/0x110
[  +0.000015]  device_release_driver_internal+0xf8/0x190
[  +0.000017]  pci_stop_bus_device+0xb5/0xf0
[  +0.000014]  pci_stop_and_remove_bus_device+0xe/0x20
[  +0.000016]  pci_iov_remove_virtfn+0x19c/0x230
[  +0.000015]  sriov_disable+0x4f/0x170
[  +0.000014]  ice_free_vfs+0x9a/0x490 [ice]
[  +0.000306]  ice_sriov_configure+0xb8/0x260 [ice]
[  +0.000294]  sriov_numvfs_store+0x1bc/0x200
[  +0.000015]  kernfs_fop_write_iter+0x1db/0x270
[  +0.000016]  new_sync_write+0x21d/0x330
[  +0.000012]  vfs_write+0x376/0x410
[  +0.000012]  ksys_write+0xba/0x150
[  +0.000012]  do_syscall_64+0x3a/0x80
[  +0.000012]  entry_SYSCALL_64_after_hwframe+0x44/0xae

[  +0.000025] The buggy address belongs to the object at ffff889908eb6f00
               which belongs to the cache kmalloc-96 of size 96
[  +0.000016] The buggy address is located 40 bytes inside of
               96-byte region [ffff889908eb6f00, ffff889908eb6f60)

[  +0.000026] The buggy address belongs to the physical page:
[  +0.000010] page:00000000b7e99a2e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1908eb6
[  +0.000016] flags: 0x57ffffc0000200(slab|node=1|zone=2|lastcpupid=0x1fffff)
[  +0.000024] raw: 0057ffffc0000200 ffffea0069d9fd80 dead000000000002 ffff88810004c780
[  +0.000015] raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
[  +0.000009] page dumped because: kasan: bad access detected

[  +0.000016] Memory state around the buggy address:
[  +0.000012]  ffff889908eb6e00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[  +0.000014]  ffff889908eb6e80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[  +0.000014] >ffff889908eb6f00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[  +0.000011]                                   ^
[  +0.000013]  ffff889908eb6f80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[  +0.000013]  ffff889908eb7000: fa fb fb fb fb fb fb fb fc fc fc fc fa fb fb fb
[  +0.000012] ==================================================================

Fixes: 0891c896 ("ice: warn about potentially malicious VFs")
Reported-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>