ice: ensure the copied buf is NUL terminated

Currently, we allocate a count-sized kernel buffer and copy count bytes
from userspace to that buffer. Later, we use sscanf on this buffer but we
don't ensure that the string is terminated inside the buffer, this can lead
to OOB read when using sscanf. Fix this issue by using memdup_user_nul
instead of memdup_user.

Fixes: 96a9a934 ("ice: configure FW logging")
Fixes: 73671c31 ("ice: enable FW logging")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://lore.kernel.org/r/20240424-fix-oob-read-v2-1-f1f1b53a10f4@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>