ksmbd: fix UAF issue in ksmbd_tcp_new_connection()

The race is between the handling of a new TCP connection and
its disconnection. It leads to UAF on `struct tcp_transport` in
ksmbd_tcp_new_connection() function.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-22991
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

ksmbd: Add missing set_freezable() for freezable kthread

The kernel thread function ksmbd_conn_handler_loop() invokes
the try_to_freeze() in its loop. But all the kernel threads are
non-freezable by default. So if we want to make a kernel thread to be
freezable, we have to invoke set_freezable() explicitly.

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

ksmbd: no need to wait for binded connection termination at logoff

The connection could be binded to the existing session for Multichannel.
session will be destroyed when binded connections are released.
So no need to wait for that's connection at logoff.

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

ksmbd: fix race condition between session lookup and expire

Thread A + Thread B
ksmbd_session_lookup | smb2_sess_setup
sess = xa_load |
|
| xa_erase(&conn->sessions, sess->id);
|
| ksmbd_session_destroy(sess) --> kfree(sess)
|
// UAF! |
sess->last_active = jiffies |
+

This patch add rwsem to fix race condition between ksmbd_session_lookup
and ksmbd_expire_session.

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

ksmbd: check iov vector index in ksmbd_conn_write()

If ->iov_idx is zero, This means that the iov vector for the response
was not added during the request process. In other words, it means that
there is a problem in generating a response, So this patch return as
an error to avoid NULL pointer dereferencing problem.

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

ksmbd: add support for read compound

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>

ksmbd: validate smb request protocol id

This patch add the validation for smb request protocol id.
If it is not one of the four ids(SMB1_PROTO_NUMBER, SMB2_PROTO_NUMBER,
SMB2_TRANSFORM_PROTO_NUM, SMB2_COMPRESSION_TRANSFORM_ID), don't allow
processing the request. And this will fix the following KASAN warning
also.

[ 13.905265] BUG: KASAN: slab-out-of-bounds in init_smb2_rsp_hdr+0x1b9/0x1f0
[ 13.905900] Read of size 16 at addr ffff888005fd2f34 by task kworker/0:2/44
...
[ 13.908553] Call Trace:
[ 13.908793] <TASK>
[ 13.908995] dump_stack_lvl+0x33/0x50
[ 13.909369] print_report+0xcc/0x620
[ 13.910870] kasan_report+0xae/0xe0
[ 13.911519] kasan_check_range+0x35/0x1b0
[ 13.911796] init_smb2_rsp_hdr+0x1b9/0x1f0
[ 13.912492] handle_ksmbd_work+0xe5/0x820

Cc: stable@vger.kernel.org
Reported-by: Chih-Yen Chang <cc85nod@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

ksmbd: check the validation of pdu_size in ksmbd_conn_handler_loop

The length field of netbios header must be greater than the SMB header
sizes(smb1 or smb2 header), otherwise the packet is an invalid SMB packet.

If `pdu_size` is 0, ksmbd allocates a 4 bytes chunk to `conn->request_buf`.
In the function `get_smb2_cmd_val` ksmbd will read cmd from
`rcv_hdr->Command`, which is `conn->request_buf + 12`, causing the KASAN
detector to print the following error message:

[ 7.205018] BUG: KASAN: slab-out-of-bounds in get_smb2_cmd_val+0x45/0x60
[ 7.205423] Read of size 2 at addr ffff8880062d8b50 by task ksmbd:42632/248
...
[ 7.207125] <TASK>
[ 7.209191] get_smb2_cmd_val+0x45/0x60
[ 7.209426] ksmbd_conn_enqueue_request+0x3a/0x100
[ 7.209712] ksmbd_server_process_request+0x72/0x160
[ 7.210295] ksmbd_conn_handler_loop+0x30c/0x550
[ 7.212280] kthread+0x160/0x190
[ 7.212762] ret_from_fork+0x1f/0x30
[ 7.212981] </TASK>

Cc: stable@vger.kernel.org
Reported-by: Chih-Yen Chang <cc85nod@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: move client and server files to common directory fs/smb

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>