if thread A in smb2_write is using work-tcon, other thread B use
smb2_tree_disconnect free the tcon, then thread A will use free'd tcon.

                            Time
                             +
 Thread A                    | Thread A
 smb2_write                  | smb2_tree_disconnect
                             |
                             |
                             |   kfree(tree_conn)
                             |
  // UAF!                    |
  work->tcon->share_conf     |
                             +

This patch add state, reference count and lock for tree conn to fix race
condition issue.

Reported-by: luosili <rootlab@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

If smb2 request from client is invalid, The following kernel oops could
happen. The patch e2b76ab8b5c9: "ksmbd: add support for read compound"
leads this issue. When request is invalid, It doesn't set anything in
the response buffer. This patch add missing set invalid parameter error
response.

[  673.085542] ksmbd: cli req too short, len 184 not 142. cmd:5 mid:109
[  673.085580] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  673.085591] #PF: supervisor read access in kernel mode
[  673.085600] #PF: error_code(0x0000) - not-present page
[  673.085608] PGD 0 P4D 0
[  673.085620] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  673.085631] CPU: 3 PID: 1039 Comm: kworker/3:0 Not tainted 6.6.0-rc2-tmt #16
[  673.085643] Hardware name: AZW U59/U59, BIOS JTKT001 05/05/2022
[  673.085651] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd]
[  673.085719] RIP: 0010:ksmbd_conn_write+0x68/0xc0 [ksmbd]
[  673.085808] RAX: 0000000000000000 RBX: ffff88811ade4f00 RCX: 0000000000000000
[  673.085817] RDX: 0000000000000000 RSI: ffff88810c2a9780 RDI: ffff88810c2a9ac0
[  673.085826] RBP: ffffc900005e3e00 R08: 0000000000000000 R09: 0000000000000000
[  673.085834] R10: ffffffffa3168160 R11: 63203a64626d736b R12: ffff8881057c8800
[  673.085842] R13: ffff8881057c8820 R14: ffff8882781b2380 R15: ffff8881057c8800
[  673.085852] FS:  0000000000000000(0000) GS:ffff888278180000(0000) knlGS:0000000000000000
[  673.085864] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  673.085872] CR2: 0000000000000000 CR3: 000000015b63c000 CR4: 0000000000350ee0
[  673.085883] Call Trace:
[  673.085890]  <TASK>
[  673.085900]  ? show_regs+0x6a/0x80
[  673.085916]  ? __die+0x25/0x70
[  673.085926]  ? page_fault_oops+0x154/0x4b0
[  673.085938]  ? tick_nohz_tick_stopped+0x18/0x50
[  673.085954]  ? __irq_work_queue_local+0xba/0x140
[  673.085967]  ? do_user_addr_fault+0x30f/0x6c0
[  673.085979]  ? exc_page_fault+0x79/0x180
[  673.085992]  ? asm_exc_page_fault+0x27/0x30
[  673.086009]  ? ksmbd_conn_write+0x68/0xc0 [ksmbd]
[  673.086067]  ? ksmbd_conn_write+0x46/0xc0 [ksmbd]
[  673.086123]  handle_ksmbd_work+0x28d/0x4b0 [ksmbd]
[  673.086177]  process_one_work+0x178/0x350
[  673.086193]  ? __pfx_worker_thread+0x10/0x10
[  673.086202]  worker_thread+0x2f3/0x420
[  673.086210]  ? _raw_spin_unlock_irqrestore+0x27/0x50
[  673.086222]  ? __pfx_worker_thread+0x10/0x10
[  673.086230]  kthread+0x103/0x140
[  673.086242]  ? __pfx_kthread+0x10/0x10
[  673.086253]  ret_from_fork+0x39/0x60
[  673.086263]  ? __pfx_kthread+0x10/0x10
[  673.086274]  ret_from_fork_asm+0x1b/0x30

Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound")
Reported-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

ksmbd has made significant improvements over the past two
years and is regularly tested and used.  Remove the experimental
warning.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

MacOS sends a compound request including read to the server
(e.g. open-read-close). So far, ksmbd has not handled read as
a compound request. For compatibility between ksmbd and an OS that
supports SMB, This patch provides compound support for read requests.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

If client send smb2 negotiate request and then send smb1 negotiate
request, init_smb2_rsp_hdr is called for smb1 negotiate request since
need_neg is set to false. This patch ignore smb1 packets after ->need_neg
is set to false.

Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21541
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

This patch validate session id and tree id in compound request.
If first operation in the compound is SMB2 ECHO request, ksmbd bypass
session and tree validation. So work->sess and work->tcon could be NULL.
If secound request in the compound access work->sess or tcon, It cause
NULL pointer dereferecing error.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21165
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:

   fs/cifs --> fs/smb/client
   fs/ksmbd --> fs/smb/server
   fs/smbfs_common --> fs/smb/common

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>