ksmbd: fix out of bounds read in smb2_sess_setup

mainline inclusion
from mainline-v6.5-rc1
commit 98422bdd
category: bugfix
bugzilla: 189112, https://gitee.com/openeuler/kernel/issues/I7SVRC
CVE: CVE-2023-3867

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8



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ksmbd does not consider the case of that smb2 session setup is
in compound request. If this is the second payload of the compound,
OOB read issue occurs while processing the first payload in
the smb2_sess_setup().

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21355
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Li Nan <linan122@huawei.com>