When user deletes a tcmu device via configFS, tcmu calls
uio_unregister_device(). During that call uio resets its pointer to struct
uio_info provided by tcmu. That means, after uio_unregister_device() uio
will no longer execute any of the callbacks tcmu had set in uio_info.

Especially, if userspace daemon still holds the corresponding uio device
open or mmap'ed while tcmu calls uio_unregister_device(), uio will not call
tcmu_release() when userspace finally closes and munmaps the uio device.

Since tcmu does refcounting for the tcmu device in tcmu_open() and
tcmu_release(), in the decribed case refcount does not drop to 0 and tcmu
does not free tcmu device's resources.  In extreme cases this can cause
memory leaking of up to 1 GB for a single tcmu device.

After uio_unregister_device(), uio will reject every open, read, write,
mmap from userspace with -EOI. But userspace daemon can still access the
mmap'ed command ring and data area. Therefore tcmu should wait until
userspace munmaps the uio device before it frees the resources, as we don't
want to cause SIGSEGV or SIGBUS to user space.

That said, current refcounting during tcmu_open and tcmu_release does not
work correctly, and refcounting better should be done in the open and close
callouts of the vm_operations_struct, which tcmu assigns to each mmap of
the uio device (because it wants its own page fault handler).

This patch fixes the memory leak by removing refcounting from tcmu_open and
tcmu_close, and instead adding new tcmu_vma_open() and tcmu_vma_close()
handlers that only do refcounting.

Link: https://lore.kernel.org/r/20210218175039.7829-3-bostroesser@gmail.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

This patch just moves one block of code containing some functions inside
target_core_user.c to avoid adding prototypes in next patch.

Link: https://lore.kernel.org/r/20210218175039.7829-2-bostroesser@gmail.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Commit a35129024e88 ("scsi: target: tcmu: Use priv pointer in se_cmd")
modified tcmu_free_cmd() to set NULL to priv pointer in se_cmd. However,
se_cmd can be already freed by work queue triggered in
target_complete_cmd(). This caused BUG KASAN use-after-free [1].

To fix the bug, do not touch priv pointer in tcmu_free_cmd(). Instead, set
NULL to priv pointer before target_complete_cmd() calls. Also, to avoid
unnecessary priv pointer change in tcmu_queue_cmd(), modify priv pointer in
the function only when tcmu_free_cmd() is not called.

[1]
BUG: KASAN: use-after-free in tcmu_handle_completions+0x1172/0x1770 [target_core_user]
Write of size 8 at addr ffff88814cf79a40 by task cmdproc-uio0/14842

CPU: 2 PID: 14842 Comm: cmdproc-uio0 Not tainted 5.11.0-rc2 #1
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 3.2 11/22/2019
Call Trace:
 dump_stack+0x9a/0xcc
 ? tcmu_handle_completions+0x1172/0x1770 [target_core_user]
 print_address_description.constprop.0+0x18/0x130
 ? tcmu_handle_completions+0x1172/0x1770 [target_core_user]
 ? tcmu_handle_completions+0x1172/0x1770 [target_core_user]
 kasan_report.cold+0x7f/0x10e
 ? tcmu_handle_completions+0x1172/0x1770 [target_core_user]
 tcmu_handle_completions+0x1172/0x1770 [target_core_user]
 ? queue_tmr_ring+0x5d0/0x5d0 [target_core_user]
 tcmu_irqcontrol+0x28/0x60 [target_core_user]
 uio_write+0x155/0x230
 ? uio_vma_fault+0x460/0x460
 ? security_file_permission+0x4f/0x440
 vfs_write+0x1ce/0x860
 ksys_write+0xe9/0x1b0
 ? __ia32_sys_read+0xb0/0xb0
 ? syscall_enter_from_user_mode+0x27/0x70
 ? trace_hardirqs_on+0x1c/0x110
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fcf8b61905f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 b9 fc ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 0c fd ff ff 48
RSP: 002b:00007fcf7b3e6c30 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcf8b61905f
RDX: 0000000000000004 RSI: 00007fcf7b3e6c78 RDI: 000000000000000c
RBP: 00007fcf7b3e6c80 R08: 0000000000000000 R09: 00007fcf7b3e6aa8
R10: 000000000b01c000 R11: 0000000000000293 R12: 00007ffe0c32a52e
R13: 00007ffe0c32a52f R14: 0000000000000000 R15: 00007fcf7b3e7640

Allocated by task 383:
 kasan_save_stack+0x1b/0x40
 ____kasan_kmalloc.constprop.0+0x84/0xa0
 kmem_cache_alloc+0x142/0x330
 tcm_loop_queuecommand+0x2a/0x4e0 [tcm_loop]
 scsi_queue_rq+0x12ec/0x2d20
 blk_mq_dispatch_rq_list+0x30a/0x1db0
 __blk_mq_do_dispatch_sched+0x326/0x830
 __blk_mq_sched_dispatch_requests+0x2c8/0x3f0
 blk_mq_sched_dispatch_requests+0xca/0x120
 __blk_mq_run_hw_queue+0x93/0xe0
 process_one_work+0x7b6/0x1290
 worker_thread+0x590/0xf80
 kthread+0x362/0x430
 ret_from_fork+0x22/0x30

Freed by task 11655:
 kasan_save_stack+0x1b/0x40
 kasan_set_track+0x1c/0x30
 kasan_set_free_info+0x20/0x30
 ____kasan_slab_free+0xec/0x120
 slab_free_freelist_hook+0x53/0x160
 kmem_cache_free+0xf4/0x5c0
 target_release_cmd_kref+0x3ea/0x9e0 [target_core_mod]
 transport_generic_free_cmd+0x28b/0x2f0 [target_core_mod]
 target_complete_ok_work+0x250/0xac0 [target_core_mod]
 process_one_work+0x7b6/0x1290
 worker_thread+0x590/0xf80
 kthread+0x362/0x430
 ret_from_fork+0x22/0x30

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40
 kasan_record_aux_stack+0xa3/0xb0
 insert_work+0x48/0x2e0
 __queue_work+0x4e8/0xdf0
 queue_work_on+0x78/0x80
 tcmu_handle_completions+0xad0/0x1770 [target_core_user]
 tcmu_irqcontrol+0x28/0x60 [target_core_user]
 uio_write+0x155/0x230
 vfs_write+0x1ce/0x860
 ksys_write+0xe9/0x1b0
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Second to last potentially related work creation:
 kasan_save_stack+0x1b/0x40
 kasan_record_aux_stack+0xa3/0xb0
 insert_work+0x48/0x2e0
 __queue_work+0x4e8/0xdf0
 queue_work_on+0x78/0x80
 tcm_loop_queuecommand+0x1c3/0x4e0 [tcm_loop]
 scsi_queue_rq+0x12ec/0x2d20
 blk_mq_dispatch_rq_list+0x30a/0x1db0
 __blk_mq_do_dispatch_sched+0x326/0x830
 __blk_mq_sched_dispatch_requests+0x2c8/0x3f0
 blk_mq_sched_dispatch_requests+0xca/0x120
 __blk_mq_run_hw_queue+0x93/0xe0
 process_one_work+0x7b6/0x1290
 worker_thread+0x590/0xf80
 kthread+0x362/0x430
 ret_from_fork+0x22/0x30

The buggy address belongs to the object at ffff88814cf79800 which belongs
to the cache tcm_loop_cmd_cache of size 896.

Link: https://lore.kernel.org/r/20210113024508.1264992-1-shinichiro.kawasaki@wdc.com
Fixes: a35129024e88 ("scsi: target: tcmu: Use priv pointer in se_cmd")
Cc: stable@vger.kernel.org # v5.9+
Acked-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Pull SCSI updates from James Bottomley:
 "This consists of the usual driver updates (ufs, qla2xxx, smartpqi,
  target, zfcp, fnic, mpt3sas, ibmvfc) plus a load of cleanups, a major
  power management rework and a load of assorted minor updates.

  There are a few core updates (formatting fixes being the big one) but
  nothing major this cycle"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (279 commits)
  scsi: mpt3sas: Update driver version to 36.100.00.00
  scsi: mpt3sas: Handle trigger page after firmware update
  scsi: mpt3sas: Add persistent MPI trigger page
  scsi: mpt3sas: Add persistent SCSI sense trigger page
  scsi: mpt3sas: Add persistent Event trigger page
  scsi: mpt3sas: Add persistent Master trigger page
  scsi: mpt3sas: Add persistent trigger pages support
  scsi: mpt3sas: Sync time periodically between driver and firmware
  scsi: qla2xxx: Update version to 10.02.00.104-k
  scsi: qla2xxx: Fix device loss on 4G and older HBAs
  scsi: qla2xxx: If fcport is undergoing deletion complete I/O with retry
  scsi: qla2xxx: Fix the call trace for flush workqueue
  scsi: qla2xxx: Fix flash update in 28XX adapters on big endian machines
  scsi: qla2xxx: Handle aborts correctly for port undergoing deletion
  scsi: qla2xxx: Fix N2N and NVMe connect retry failure
  scsi: qla2xxx: Fix FW initialization error on big endian machines
  scsi: qla2xxx: Fix crash during driver load on big endian machines
  scsi: qla2xxx: Fix compilation issue in PPC systems
  scsi: qla2xxx: Don't check for fw_started while posting NVMe command
  scsi: qla2xxx: Tear down session if FW say it is down
  ...

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

scatter_data_area() and gather_data_area() are not easy to understand since
data is copied in nested loops over sg_list and tcmu dbi list. Since sg
list can contain only partly filled pages, the loop has to be prepared to
handle sg pages not matching dbi pages one by one.

Existing implementation uses kmap_atomic()/kunmap_atomic() due to
performance reasons. But instead of using these calls strictly nested for
sg and dpi pages, the code holds the mappings in an overlapping way, which
indeed is a bug that would trigger on archs using highmem.

The scatterlist lib contains the sg_miter_start/_next/_stop functions which
can be used to simplify such complicated loops.

The new code now processes the dbi list in the outer loop, while sg list is
handled by the inner one. That way the code can take advantage of the
sg_miter_* family calls.

Calling sg_miter_stop() after the end of the inner loop enforces strict
nesting of atomic kmaps.

Since the nested loops in scatter_/gather_data_area were very similar, I
replaced them by the new helper function tcmu_copy_data().

Link: https://lore.kernel.org/r/20201019115118.11949-1-bostroesser@gmail.com
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Pull networking updates from Jakub Kicinski:

 - Add redirect_neigh() BPF packet redirect helper, allowing to limit
   stack traversal in common container configs and improving TCP
   back-pressure.

   Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.

 - Expand netlink policy support and improve policy export to user
   space. (Ge)netlink core performs request validation according to
   declared policies. Expand the expressiveness of those policies
   (min/max length and bitmasks). Allow dumping policies for particular
   commands. This is used for feature discovery by user space (instead
   of kernel version parsing or trial and error).

 - Support IGMPv3/MLDv2 multicast listener discovery protocols in
   bridge.

 - Allow more than 255 IPv4 multicast interfaces.

 - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
   packets of TCPv6.

 - In Multi-patch TCP (MPTCP) support concurrent transmission of data on
   multiple subflows in a load balancing scenario. Enhance advertising
   addresses via the RM_ADDR/ADD_ADDR options.

 - Support SMC-Dv2 version of SMC, which enables multi-subnet
   deployments.

 - Allow more calls to same peer in RxRPC.

 - Support two new Controller Area Network (CAN) protocols - CAN-FD and
   ISO 15765-2:2016.

 - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
   kernel problem.

 - Add TC actions for implementing MPLS L2 VPNs.

 - Improve nexthop code - e.g. handle various corner cases when nexthop
   objects are removed from groups better, skip unnecessary
   notifications and make it easier to offload nexthops into HW by
   converting to a blocking notifier.

 - Support adding and consuming TCP header options by BPF programs,
   opening the doors for easy experimental and deployment-specific TCP
   option use.

 - Reorganize TCP congestion control (CC) initialization to simplify
   life of TCP CC implemented in BPF.

 - Add support for shipping BPF programs with the kernel and loading
   them early on boot via the User Mode Driver mechanism, hence reusing
   all the user space infra we have.

 - Support sleepable BPF programs, initially targeting LSM and tracing.

 - Add bpf_d_path() helper for returning full path for given 'struct
   path'.

 - Make bpf_tail_call compatible with bpf-to-bpf calls.

 - Allow BPF programs to call map_update_elem on sockmaps.

 - Add BPF Type Format (BTF) support for type and enum discovery, as
   well as support for using BTF within the kernel itself (current use
   is for pretty printing structures).

 - Support listing and getting information about bpf_links via the bpf
   syscall.

 - Enhance kernel interfaces around NIC firmware update. Allow
   specifying overwrite mask to control if settings etc. are reset
   during update; report expected max time operation may take to users;
   support firmware activation without machine reboot incl. limits of
   how much impact reset may have (e.g. dropping link or not).

 - Extend ethtool configuration interface to report IEEE-standard
   counters, to limit the need for per-vendor logic in user space.

 - Adopt or extend devlink use for debug, monitoring, fw update in many
   drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx,
   dpaa2-eth).

 - In mlxsw expose critical and emergency SFP module temperature alarms.
   Refactor port buffer handling to make the defaults more suitable and
   support setting these values explicitly via the DCBNL interface.

 - Add XDP support for Intel's igb driver.

 - Support offloading TC flower classification and filtering rules to
   mscc_ocelot switches.

 - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
   fixed interval period pulse generator and one-step timestamping in
   dpaa-eth.

 - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
   offload.

 - Add Lynx PHY/PCS MDIO module, and convert various drivers which have
   this HW to use it. Convert mvpp2 to split PCS.

 - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
   7-port Mediatek MT7531 IP.

 - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
   and wcn3680 support in wcn36xx.

 - Improve performance for packets which don't require much offloads on
   recent Mellanox NICs by 20% by making multiple packets share a
   descriptor entry.

 - Move chelsio inline crypto drivers (for TLS and IPsec) from the
   crypto subtree to drivers/net. Move MDIO drivers out of the phy
   directory.

 - Clean up a lot of W=1 warnings, reportedly the actively developed
   subsections of networking drivers should now build W=1 warning free.

 - Make sure drivers don't use in_interrupt() to dynamically adapt their
   code. Convert tasklets to use new tasklet_setup API (sadly this
   conversion is not yet complete).

* tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits)
  Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH"
  net, sockmap: Don't call bpf_prog_put() on NULL pointer
  bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo
  bpf, sockmap: Add locking annotations to iterator
  netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements
  net: fix pos incrementment in ipv6_route_seq_next
  net/smc: fix invalid return code in smcd_new_buf_create()
  net/smc: fix valid DMBE buffer sizes
  net/smc: fix use-after-free of delayed events
  bpfilter: Fix build error with CONFIG_BPFILTER_UMH
  cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr
  net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
  bpf: Fix register equivalence tracking.
  rxrpc: Fix loss of final ack on shutdown
  rxrpc: Fix bundle counting for exclusive connections
  netfilter: restore NF_INET_NUMHOOKS
  ibmveth: Identify ingress large send packets.
  ibmveth: Switch order of ibmveth_helper calls.
  cxgb4: handle 4-tuple PEDIT to NAT mode translation
  selftests: Add VRF route leaking tests
  ...

Bulk of the genetlink users can use smaller ops, move them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Corrects drivers/target/target_core_user.c:688:6: warning: 'page' may be
used uninitialized.

Link: https://lore.kernel.org/r/20200924001920.43594-1-john.p.donnelly@oracle.com
Fixes: 3c58f737231e ("scsi: target: tcmu: Optimize use of flush_dcache_page")
Cc: Mike Christie <michael.christie@oracle.com>
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: John Donnelly <john.p.donnelly@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scatter_data_area() has two purposes:

 1) Create the iovs for the data area buffer of a SCSI cmd.

 2) If there is data in DMA_TO_DEVICE direction, copy
    the data from sg_list to data area buffer.

Both are done in a common loop.

In case of DMA_FROM_DEVICE data transfer, scatter_data_area() is called
with parameter copy_data = false. But this flag is just used to skip
memcpy() for data, while radix_tree_lookup still is called for every dbi of
the area area buffer, and kmap and kunmap are called for every page from
sg_list and data_area as well as flush_dcache_page() for the data area
pages.  Since the only thing to do with copy_data = false would be to set
up the iovs, this is a noticeable overhead.  Rework the iov creation in the
main loop of scatter_data_area() providing the new function
new_block_to_iov().  Based on this, create the short new function
tcmu_setup_iovs() that only writes the iovs with no overhead.  This new
function is now called instead of scatter_data_area() for bidi buffers and
for data buffers in those cases where memcpy() would have been skipped.

Link: https://lore.kernel.org/r/20200910155041.17654-4-bstroesser@ts.fujitsu.com
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>