scsi: lpfc: Prevent lpfc_debugfs_lockstat_write() buffer overflow

stable inclusion
from stable-v5.10.181
commit e0e7faee3a7dd6f51350cda64997116a247eb045
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7ZCDZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.197&id=e0e7faee3a7dd6f51350cda64997116a247eb045

--------------------------------

[ Upstream commit c6087b82 ]

A static code analysis tool flagged the possibility of buffer overflow when
using copy_from_user() for a debugfs entry.

Currently, it is possible that copy_from_user() copies more bytes than what
would fit in the mybuf char array.  Add a min() restriction check between
sizeof(mybuf) - 1 and nbytes passed from the userspace buffer to protect
against buffer overflow.

Link: https://lore.kernel.org/r/20230301231626.9621-2-justintee8345@gmail.com


Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yong Hu <yong.hu@windriver.com>