linux-stable.git/drivers/block/nbd.c, branch v6.7

nbd: pass nbd_sock to nbd_read_reply() instead of index

2023-11-21T14:42:04+00:00

If a socket is processing ioctl 'NBD_SET_SOCK', config->socks might be
krealloc in nbd_add_socket(), and a garbage request is received now, a UAF
may occurs.

  T1
  nbd_ioctl
   __nbd_ioctl
    nbd_add_socket
     blk_mq_freeze_queue
				T2
  				recv_work
  				 nbd_read_reply
  				  sock_xmit
     krealloc config->socks
				   def config->socks

Pass nbd_sock to nbd_read_reply(). And introduce a new function
sock_xmit_recv(), which differs from sock_xmit only in the way it get
socket.

==================================================================
BUG: KASAN: use-after-free in sock_xmit+0x525/0x550
Read of size 8 at addr ffff8880188ec428 by task kworker/u12:1/18779

Workqueue: knbd4-recv recv_work
Call Trace:
 __dump_stack
 dump_stack+0xbe/0xfd
 print_address_description.constprop.0+0x19/0x170
 __kasan_report.cold+0x6c/0x84
 kasan_report+0x3a/0x50
 sock_xmit+0x525/0x550
 nbd_read_reply+0xfe/0x2c0
 recv_work+0x1c2/0x750
 process_one_work+0x6b6/0xf10
 worker_thread+0xdd/0xd80
 kthread+0x30a/0x410
 ret_from_fork+0x22/0x30

Allocated by task 18784:
 kasan_save_stack+0x1b/0x40
 kasan_set_track
 set_alloc_info
 __kasan_kmalloc
 __kasan_kmalloc.constprop.0+0xf0/0x130
 slab_post_alloc_hook
 slab_alloc_node
 slab_alloc
 __kmalloc_track_caller+0x157/0x550
 __do_krealloc
 krealloc+0x37/0xb0
 nbd_add_socket
 +0x2d3/0x880
 __nbd_ioctl
 nbd_ioctl+0x584/0x8e0
 __blkdev_driver_ioctl
 blkdev_ioctl+0x2a0/0x6e0
 block_ioctl+0xee/0x130
 vfs_ioctl
 __do_sys_ioctl
 __se_sys_ioctl+0x138/0x190
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Freed by task 18784:
 kasan_save_stack+0x1b/0x40
 kasan_set_track+0x1c/0x30
 kasan_set_free_info+0x20/0x40
 __kasan_slab_free.part.0+0x13f/0x1b0
 slab_free_hook
 slab_free_freelist_hook
 slab_free
 kfree+0xcb/0x6c0
 krealloc+0x56/0xb0
 nbd_add_socket+0x2d3/0x880
 __nbd_ioctl
 nbd_ioctl+0x584/0x8e0
 __blkdev_driver_ioctl
 blkdev_ioctl+0x2a0/0x6e0
 block_ioctl+0xee/0x130
 vfs_ioctl
 __do_sys_ioctl
 __se_sys_ioctl+0x138/0x190
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Signed-off-by: Li Nan 
Reviewed-by: Yu Kuai 
Reviewed-by: Ming Lei 
Link: https://lore.kernel.org/r/20230911023308.3467802-1-linan666@huaweicloud.com
Signed-off-by: Jens Axboe

nbd: fix null-ptr-dereference while accessing 'nbd->config'

2023-11-20T17:16:44+00:00

Memory reordering may occur in nbd_genl_connect(), causing config_refs
to be set to 1 while nbd->config is still empty. Opening nbd at this
time will cause null-ptr-dereference.

   T1                      T2
   nbd_open
    nbd_get_config_unlocked
                 	   nbd_genl_connect
                 	    nbd_alloc_and_init_config
                 	     //memory reordered
                  	     refcount_set(&nbd->config_refs, 1)  // 2
     nbd->config
      ->null point
			     nbd->config = config  // 1

Fix it by adding smp barrier to guarantee the execution sequence.

Signed-off-by: Li Nan 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20231116162316.1740402-4-linan666@huaweicloud.com
Signed-off-by: Jens Axboe

nbd: factor out a helper to get nbd_config without holding 'config_lock'

2023-11-20T17:16:44+00:00

There are no functional changes, just to make code cleaner and prepare
to fix null-ptr-dereference while accessing 'nbd->config'.

Signed-off-by: Li Nan 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20231116162316.1740402-3-linan666@huaweicloud.com
Signed-off-by: Jens Axboe

nbd: fold nbd config initialization into nbd_alloc_config()

2023-11-20T17:16:44+00:00

There are no functional changes, make the code cleaner and prepare to
fix null-ptr-dereference while accessing 'nbd->config'.

Signed-off-by: Li Nan 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20231116162316.1740402-2-linan666@huaweicloud.com
Signed-off-by: Jens Axboe

nbd: fix uaf in nbd_open

2023-11-07T15:14:57+00:00

Commit 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and
blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set
disk->private_data as NULL as before. UAF may be triggered in nbd_open()
if someone tries to open nbd device right after nbd_put() since nbd has
been free in nbd_dev_remove().

Fix this by implementing ->free_disk and free private data in it.

Fixes: 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk")
Signed-off-by: Li Lingfeng 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20231107103435.2074904-1-lilingfeng@huaweicloud.com
Signed-off-by: Jens Axboe

nbd: don't call blk_mark_disk_dead nbd_clear_sock_ioctl

2023-10-04T00:27:44+00:00

blk_mark_disk_dead is the proper interface to shut down a block
device, but it also makes the disk unusable forever.

nbd_clear_sock_ioctl on the other hand wants to shut down the file
system, but allow the block device to be used again when when connected
to another socket.  Switch nbd to use disk_force_media_change and
nbd_bdev_reset to go back to a behavior of the old __invalidate_device
call, with the added benefit of incrementing the device generation
as there is no guarantee the old content comes back when the device
is reconnected.

Reported-by: Samuel Holland 
Reported-by: Shinichiro Kawasaki 
Fixes: 0c1c9a27ce90 ("nbd: call blk_mark_disk_dead in nbd_clear_sock_ioctl")
Signed-off-by: Christoph Hellwig 
Tested-by: Samuel Holland 
Link: https://lore.kernel.org/r/20231003153106.1331363-1-hch@lst.de
Signed-off-by: Jens Axboe

Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux

2023-08-30T03:21:42+00:00

Pull block updates from Jens Axboe:
 "Pretty quiet round for this release. This contains:

   - Add support for zoned storage to ublk (Andreas, Ming)

   - Series improving performance for drivers that mark themselves as
     needing a blocking context for issue (Bart)

   - Cleanup the flush logic (Chengming)

   - sed opal keyring support (Greg)

   - Fixes and improvements to the integrity support (Jinyoung)

   - Add some exports for bcachefs that we can hopefully delete again in
     the future (Kent)

   - deadline throttling fix (Zhiguo)

   - Series allowing building the kernel without buffer_head support
     (Christoph)

   - Sanitize the bio page adding flow (Christoph)

   - Write back cache fixes (Christoph)

   - MD updates via Song:
      - Fix perf regression for raid0 large sequential writes (Jan)
      - Fix split bio iostat for raid0 (David)
      - Various raid1 fixes (Heinz, Xueshi)
      - raid6test build fixes (WANG)
      - Deprecate bitmap file support (Christoph)
      - Fix deadlock with md sync thread (Yu)
      - Refactor md io accounting (Yu)
      - Various non-urgent fixes (Li, Yu, Jack)

   - Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li,
     Ming, Nitesh, Ruan, Tejun, Thomas, Xu)"

* tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits)
  block: use strscpy() to instead of strncpy()
  block: sed-opal: keyring support for SED keys
  block: sed-opal: Implement IOC_OPAL_REVERT_LSP
  block: sed-opal: Implement IOC_OPAL_DISCOVERY
  blk-mq: prealloc tags when increase tagset nr_hw_queues
  blk-mq: delete redundant tagset map update when fallback
  blk-mq: fix tags leak when shrink nr_hw_queues
  ublk: zoned: support REQ_OP_ZONE_RESET_ALL
  md: raid0: account for split bio in iostat accounting
  md/raid0: Fix performance regression for large sequential writes
  md/raid0: Factor out helper for mapping and submitting a bio
  md raid1: allow writebehind to work on any leg device set WriteMostly
  md/raid1: hold the barrier until handle_read_error() finishes
  md/raid1: free the r1bio before waiting for blocked rdev
  md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io()
  blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init
  drivers/rnbd: restore sysfs interface to rnbd-client
  md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid()
  raid6: test: only check for Altivec if building on powerpc hosts
  raid6: test: make sure all intermediate and artifact files are .gitignored
  ...

nbd: call blk_mark_disk_dead in nbd_clear_sock_ioctl

2023-08-21T12:35:30+00:00

nbd_clear_sock_ioctl kills the socket and with that the block
device.  Instead of just invalidating file system buffers,
mark the device as dead, which will also invalidate the buffers
as part of the proper shutdown sequence.  This also includes
invalidating partitions if there are any.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Josef Bacik 
Message-Id: <20230811100828.1897174-8-hch@lst.de>
Signed-off-by: Christian Brauner

nbd: automatically load module on genl access

2023-07-17T14:18:17+00:00

Add a module alias to nbd.ko that allows the generic netlink core to
automatically load the module when netlink messages for nbd are
received.

This frees the user from manually having to load the module before using
nbd functionality via netlink.
If the system policy allows it this can even be used to load the nbd
module from containers which would otherwise not have access to the
necessary module files to do a normal "modprobe nbd".

For example this avoids the following error when using nbd-client:

$ nbd-client localhost 10809 /dev/nbd0
...
Error: Couldn't resolve the nbd netlink family, make sure the nbd module is loaded and your nbd driver supports the netlink interface.

Signed-off-by: Thomas Weißschuh 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20230713-b4-nbd-genl-v3-1-226cbddba04b@weissschuh.net
Signed-off-by: Jens Axboe

block: replace fmode_t with a block-specific type for block open flags

2023-06-12T14:04:05+00:00

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE.  Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig 
Acked-by: Jack Wang 		[rnbd]
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christian Brauner 
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe