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

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>

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c
index 9670c97f14b3ef745a063b538881c4ec60d950ed..e7f14f8df943e22901fe42be164eb7650270ff4d 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);