ksmbd: fix slab-use-after-free in smb3_preauth_hash_rsp

commit b8fc56fbca7482c1e5c0e3351c6ae78982e25ada upstream.

ksmbd_user_session_put should be called under smb3_preauth_hash_rsp().
It will avoid freeing session before calling smb3_preauth_hash_rsp().

Cc: stable@vger.kernel.org # v5.15+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c
index f098dd17ae9a5a8d02e487b0e4bbf5ddedbc000c..b6e0b71c281dcf8bd464e0f0e8a1bde30af8095e 100644 (file)
--- a/fs/smb/server/server.c
+++ b/fs/smb/server/server.c
@@ -238,11 +238,11 @@ static void __handle_ksmbd_work(struct ksmbd_work *work,
        } while (is_chained == true);
 
 send:
-       if (work->sess)
-               ksmbd_user_session_put(work->sess);
        if (work->tcon)
                ksmbd_tree_connect_put(work->tcon);
        smb3_preauth_hash_rsp(work);
+       if (work->sess)
+               ksmbd_user_session_put(work->sess);
        if (work->sess && work->sess->enc && work->encrypted &&
            conn->ops->encrypt_resp) {
                rc = conn->ops->encrypt_resp(work);