ksmbd: fix use-after-free in ksmbd_session_rpc_open

ksmbd: fix use-after-free in ksmbd_session_rpc_open

[ Upstream commit a1f46c99d9ea411f9bf30025b912d881d36fc709 ]

A UAF issue can occur due to a race condition between
ksmbd_session_rpc_open() and __session_rpc_close().
Add rpc_lock to the session to protect it.

Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
[ KSMBD_DEFAULT_GFP is introduced by commit 0066f623bce8 ("ksmbd: use __GFP_RETRY_MAYFAIL")
 after linux-6.13. Here we still use GFP_KERNEL. ]
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>