linux-stable.git/drivers/block, branch linux-5.18.y

xen-blkfront: Apply 'feature_persistent' parameter when connect

2022-08-17T12:42:33+00:00

commit 402c43ea6b34a1b371ffeed9adf907402569eaf5 upstream.

In some use cases[1], the backend is created while the frontend doesn't
support the persistent grants feature, but later the frontend can be
changed to support the feature and reconnect.  In the past, 'blkback'
enabled the persistent grants feature since it unconditionally checked
if frontend supports the persistent grants feature for every connect
('connect_ring()') and decided whether it should use persistent grans or
not.

However, commit aac8a70db24b ("xen-blkback: add a parameter for
disabling of persistent grants") has mistakenly changed the behavior.
It made the frontend feature support check to not be repeated once it
shown the 'feature_persistent' as 'false', or the frontend doesn't
support persistent grants.

Similar behavioral change has made on 'blkfront' by commit 74a852479c68
("xen-blkfront: add a parameter for disabling of persistent grants").
This commit changes the behavior of the parameter to make effect for
every connect, so that the previous behavior of 'blkfront' can be
restored.

[1] https://lore.kernel.org/xen-devel/CAJwUmVB6H3iTs-C+U=v-pwJB7-_ZRHPxHzKRJZ22xEPW7z8a=g@mail.gmail.com/

Fixes: 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants")
Cc:  # 5.10.x
Signed-off-by: SeongJae Park 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220715225108.193398-4-sj@kernel.org
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen-blkback: Apply 'feature_persistent' parameter when connect

2022-08-17T12:42:33+00:00

commit e94c6101e151b019b8babc518ac2a6ada644a5a1 upstream.

In some use cases[1], the backend is created while the frontend doesn't
support the persistent grants feature, but later the frontend can be
changed to support the feature and reconnect.  In the past, 'blkback'
enabled the persistent grants feature since it unconditionally checked
if frontend supports the persistent grants feature for every connect
('connect_ring()') and decided whether it should use persistent grans or
not.

However, commit aac8a70db24b ("xen-blkback: add a parameter for
disabling of persistent grants") has mistakenly changed the behavior.
It made the frontend feature support check to not be repeated once it
shown the 'feature_persistent' as 'false', or the frontend doesn't
support persistent grants.

This commit changes the behavior of the parameter to make effect for
every connect, so that the previous workflow can work again as expected.

[1] https://lore.kernel.org/xen-devel/CAJwUmVB6H3iTs-C+U=v-pwJB7-_ZRHPxHzKRJZ22xEPW7z8a=g@mail.gmail.com/

Reported-by: Andrii Chepurnyi 
Fixes: aac8a70db24b ("xen-blkback: add a parameter for disabling of persistent grants")
Cc:  # 5.10.x
Signed-off-by: Maximilian Heyne 
Signed-off-by: SeongJae Park 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220715225108.193398-3-sj@kernel.org
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen-blkback: fix persistent grants negotiation

2022-08-17T12:42:33+00:00

commit fc9be616bb8f3ed9cf560308f86904f5c06be205 upstream.

Persistent grants feature can be used only when both backend and the
frontend supports the feature.  The feature was always supported by
'blkback', but commit aac8a70db24b ("xen-blkback: add a parameter for
disabling of persistent grants") has introduced a parameter for
disabling it runtime.

To avoid the parameter be updated while being used by 'blkback', the
commit caches the parameter into 'vbd->feature_gnt_persistent' in
'xen_vbd_create()', and then check if the guest also supports the
feature and finally updates the field in 'connect_ring()'.

However, 'connect_ring()' could be called before 'xen_vbd_create()', so
later execution of 'xen_vbd_create()' can wrongly overwrite 'true' to
'vbd->feature_gnt_persistent'.  As a result, 'blkback' could try to use
'persistent grants' feature even if the guest doesn't support the
feature.

This commit fixes the issue by moving the parameter value caching to
'xen_blkif_alloc()', which allocates the 'blkif'.  Because the struct
embeds 'vbd' object, which will be used by 'connect_ring()' later, this
should be called before 'connect_ring()' and therefore this should be
the right and safe place to do the caching.

Fixes: aac8a70db24b ("xen-blkback: add a parameter for disabling of persistent grants")
Cc:  # 5.10.x
Signed-off-by: Maximilian Heyne 
Signed-off-by: SeongJae Park 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220715225108.193398-2-sj@kernel.org
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

null_blk: fix ida error handling in null_add_dev()

2022-08-17T12:41:56+00:00

[ Upstream commit ee452a8d984f94fa8e894f003a52e776e4572881 ]

There needs to be some error checking if ida_simple_get() fails.
Also call ida_free() if there are errors later.

Fixes: 94bc02e30fb8 ("nullb: use ida to manage index")
Signed-off-by: Dan Carpenter 
Link: https://lore.kernel.org/r/YtEhXsr6vJeoiYhd@kili
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block/rnbd-srv: Set keep_id to true after mutex_trylock

2022-08-17T12:41:56+00:00

[ Upstream commit 4bc14f3101364877dd59085f39e068a2a7ec9f2d ]

After setting keep_id if the mutex trylock fails, the keep_id stays set
for the rest of the sess_dev lifetime.

Therefore, set keep_id to true after mutex_trylock succeeds, so that a
failure of trylock does'nt touch keep_id.

Fixes: b168e1d85cf3 ("block/rnbd-srv: Prevent a deadlock generated by accessing sysfs in parallel")
Cc: gi-oh.kim@ionos.com
Signed-off-by: Md Haris Iqbal 
Signed-off-by: Jack Wang 
Link: https://lore.kernel.org/r/20220707143122.460362-2-haris.iqbal@ionos.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

xen/blkfront: force data bouncing when backend is untrusted

2022-07-07T15:55:00+00:00

commit 2400617da7eebf9167d71a46122828bc479d64c9 upstream.

Split the current bounce buffering logic used with persistent grants
into it's own option, and allow enabling it independently of
persistent grants.  This allows to reuse the same code paths to
perform the bounce buffering required to avoid leaking contiguous data
in shared pages not part of the request fragments.

Reporting whether the backend is to be trusted can be done using a
module parameter, or from the xenstore frontend path as set by the
toolstack when adding the device.

This is CVE-2022-33742, part of XSA-403.

Signed-off-by: Roger Pau Monné 
Reviewed-by: Juergen Gross 
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen/blkfront: fix leaking data in shared pages

2022-07-07T15:55:00+00:00

commit 2f446ffe9d737e9a844b97887919c4fda18246e7 upstream.

When allocating pages to be used for shared communication with the
backend always zero them, this avoids leaking unintended data present
on the pages.

This is CVE-2022-26365, part of XSA-403.

Signed-off-by: Roger Pau Monné 
Reviewed-by: Jan Beulich 
Reviewed-by: Juergen Gross 
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen-blkfront: Handle NULL gendisk

2022-06-29T07:04:33+00:00

[ Upstream commit f9710c357e5bbf64d7ce45ba0bc75a52222491c1 ]

When a VBD is not fully created and then closed, the kernel can have a
NULL pointer dereference:

The reproducer is trivial:

[user@dom0 ~]$ sudo xl block-attach work backend=sys-usb vdev=xvdi target=/dev/sdz
[user@dom0 ~]$ xl block-list work
Vdev  BE  handle state evt-ch ring-ref BE-path
51712 0   241    4     -1     -1       /local/domain/0/backend/vbd/241/51712
51728 0   241    4     -1     -1       /local/domain/0/backend/vbd/241/51728
51744 0   241    4     -1     -1       /local/domain/0/backend/vbd/241/51744
51760 0   241    4     -1     -1       /local/domain/0/backend/vbd/241/51760
51840 3   241    3     -1     -1       /local/domain/3/backend/vbd/241/51840
                 ^ note state, the /dev/sdz doesn't exist in the backend

[user@dom0 ~]$ sudo xl block-detach work xvdi
[user@dom0 ~]$ xl block-list work
Vdev  BE  handle state evt-ch ring-ref BE-path
work is an invalid domain identifier

And its console has:

BUG: kernel NULL pointer dereference, address: 0000000000000050
PGD 80000000edebb067 P4D 80000000edebb067 PUD edec2067 PMD 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 52 Comm: xenwatch Not tainted 5.16.18-2.43.fc32.qubes.x86_64 #1
RIP: 0010:blk_mq_stop_hw_queues+0x5/0x40
Code: 00 48 83 e0 fd 83 c3 01 48 89 85 a8 00 00 00 41 39 5c 24 50 77 c0 5b 5d 41 5c 41 5d c3 c3 0f 1f 80 00 00 00 00 0f 1f 44 00 00 <8b> 47 50 85 c0 74 32 41 54 49 89 fc 55 53 31 db 49 8b 44 24 48 48
RSP: 0018:ffffc90000bcfe98 EFLAGS: 00010293
RAX: ffffffffc0008370 RBX: 0000000000000005 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: ffff88800775f000 R08: 0000000000000001 R09: ffff888006e620b8
R10: ffff888006e620b0 R11: f000000000000000 R12: ffff8880bff39000
R13: ffff8880bff39000 R14: 0000000000000000 R15: ffff88800604be00
FS:  0000000000000000(0000) GS:ffff8880f3300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000050 CR3: 00000000e932e002 CR4: 00000000003706e0
Call Trace:
 
 blkback_changed+0x95/0x137 [xen_blkfront]
 ? read_reply+0x160/0x160
 xenwatch_thread+0xc0/0x1a0
 ? do_wait_intr_irq+0xa0/0xa0
 kthread+0x16b/0x190
 ? set_kthread_struct+0x40/0x40
 ret_from_fork+0x22/0x30
 
Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device snd_timer snd soundcore ipt_REJECT nf_reject_ipv4 xt_state xt_conntrack nft_counter nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_compat nf_tables nfnetlink intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel xen_netfront pcspkr xen_scsiback target_core_mod xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn ipmi_devintf ipmi_msghandler fuse bpf_preload ip_tables overlay xen_blkfront
CR2: 0000000000000050
---[ end trace 7bc9597fd06ae89d ]---
RIP: 0010:blk_mq_stop_hw_queues+0x5/0x40
Code: 00 48 83 e0 fd 83 c3 01 48 89 85 a8 00 00 00 41 39 5c 24 50 77 c0 5b 5d 41 5c 41 5d c3 c3 0f 1f 80 00 00 00 00 0f 1f 44 00 00 <8b> 47 50 85 c0 74 32 41 54 49 89 fc 55 53 31 db 49 8b 44 24 48 48
RSP: 0018:ffffc90000bcfe98 EFLAGS: 00010293
RAX: ffffffffc0008370 RBX: 0000000000000005 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: ffff88800775f000 R08: 0000000000000001 R09: ffff888006e620b8
R10: ffff888006e620b0 R11: f000000000000000 R12: ffff8880bff39000
R13: ffff8880bff39000 R14: 0000000000000000 R15: ffff88800604be00
FS:  0000000000000000(0000) GS:ffff8880f3300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000050 CR3: 00000000e932e002 CR4: 00000000003706e0
Kernel panic - not syncing: Fatal exception
Kernel Offset: disabled

info->rq and info->gd are only set in blkfront_connect(), which is
called for state 4 (XenbusStateConnected).  Guard against using NULL
variables in blkfront_closing() to avoid the issue.

The rest of blkfront_closing looks okay.  If info->nr_rings is 0, then
for_each_rinfo won't do anything.

blkfront_remove also needs to check for non-NULL pointers before
cleaning up the gendisk and request queue.

Fixes: 05d69d950d9d "xen-blkfront: sanitize the removal state machine"
Reported-by: Marek Marczykowski-Górecki 
Signed-off-by: Jason Andryuk 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220601195341.28581-1-jandryuk@gmail.com
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

nbd: fix io hung while disconnecting device

2022-06-14T16:45:14+00:00

[ Upstream commit 09dadb5985023e27d4740ebd17e6fea4640110e5 ]

In our tests, "qemu-nbd" triggers a io hung:

INFO: task qemu-nbd:11445 blocked for more than 368 seconds.
      Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:qemu-nbd        state:D stack:    0 pid:11445 ppid:     1 flags:0x00000000
Call Trace:
 
 __schedule+0x480/0x1050
 ? _raw_spin_lock_irqsave+0x3e/0xb0
 schedule+0x9c/0x1b0
 blk_mq_freeze_queue_wait+0x9d/0xf0
 ? ipi_rseq+0x70/0x70
 blk_mq_freeze_queue+0x2b/0x40
 nbd_add_socket+0x6b/0x270 [nbd]
 nbd_ioctl+0x383/0x510 [nbd]
 blkdev_ioctl+0x18e/0x3e0
 __x64_sys_ioctl+0xac/0x120
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd8ff706577
RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577
RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f
RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0
R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d
R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0

"qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following
message was found:

block nbd0: Send disconnect failed -32

Which indicate that something is wrong with the server. Then,
"qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear
requests after commit 2516ab1543fd("nbd: only clear the queue on device
teardown"). And in the meantime, request can't complete through timeout
because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which
means such request will never be completed in this situation.

Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't
complete multiple times, switch back to call nbd_clear_sock() in
nbd_clear_sock_ioctl(), so that inflight requests can be cleared.

Signed-off-by: Yu Kuai 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220521073749.3146892-5-yukuai3@huawei.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

nbd: fix race between nbd_alloc_config() and module removal

2022-06-14T16:45:14+00:00

[ Upstream commit c55b2b983b0fa012942c3eb16384b2b722caa810 ]

When nbd module is being removing, nbd_alloc_config() may be
called concurrently by nbd_genl_connect(), although try_module_get()
will return false, but nbd_alloc_config() doesn't handle it.

The race may lead to the leak of nbd_config and its related
resources (e.g, recv_workq) and oops in nbd_read_stat() due
to the unload of nbd module as shown below:

  BUG: kernel NULL pointer dereference, address: 0000000000000040
  Oops: 0000 [#1] SMP PTI
  CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
  Workqueue: knbd16-recv recv_work [nbd]
  RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd]
  Call Trace:
   recv_work+0x3b/0xb0 [nbd]
   process_one_work+0x1ed/0x390
   worker_thread+0x4a/0x3d0
   kthread+0x12a/0x150
   ret_from_fork+0x22/0x30

Fixing it by checking the return value of try_module_get()
in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV),
assign nbd->config only when nbd_alloc_config() succeeds to ensure
the value of nbd->config is binary (valid or NULL).

Also adding a debug message to check the reference counter
of nbd_config during module removal.

Signed-off-by: Hou Tao 
Signed-off-by: Yu Kuai 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220521073749.3146892-3-yukuai3@huawei.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin