From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A9E5C433FE for ; Wed, 23 Nov 2022 07:41:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235866AbiKWHlj (ORCPT ); Wed, 23 Nov 2022 02:41:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235819AbiKWHli (ORCPT ); Wed, 23 Nov 2022 02:41:38 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B22CBF6082 for ; Tue, 22 Nov 2022 23:41:34 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 410CBB81ECD for ; Wed, 23 Nov 2022 07:41:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00E48C433D6; Wed, 23 Nov 2022 07:41:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669189292; bh=Qva04oLyBFng31pmDphEPFtjB3P1zGwSDSsZvlND0x0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=a+XR8/34wc2lNYYkx6Ts9f9yfEpGcZXewHpAxkFhuQteBFc7v+x++K8Yz6jk5mnaH YQ59mM211p+Hnitpvg7XqtZ77hmEuMMligL6hCxgQ9aOrGGumofrTJdiCTij5qs5q8 a7uBL4XUzdtOgFh2sD0uKiIL6kQ23vaJb6Oi51SOLs509VeimUZrefTGbUJFW2H9Fq k/Mny/VHV4zXzYFwWAkitLC30di/dThu7Ew+3woaNU3mMU2O7TUkGfEYyLD8ib4393 8Jt2L9Ac0QhSD964O74AJdgihD4GNverYeZ8k20Q8bERNLKwF2H2VjMVw1x/v4Spbn EYcol5Ck0poog== Date: Wed, 23 Nov 2022 09:41:24 +0200 From: Leon Romanovsky To: Yang Yingliang Cc: Jakub Kicinski , netdev@vger.kernel.org, jiri@nvidia.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com Subject: Re: [PATCH net] net: devlink: fix UAF in devlink_compat_running_version() Message-ID: References: <20221122121048.776643-1-yangyingliang@huawei.com> <20221122122740.4b10d67d@kernel.org> <405f703b-b97e-afdd-8d5f-48b8f99d045d@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <405f703b-b97e-afdd-8d5f-48b8f99d045d@huawei.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Nov 23, 2022 at 02:40:24PM +0800, Yang Yingliang wrote: > > On 2022/11/23 4:27, Jakub Kicinski wrote: > > On Tue, 22 Nov 2022 21:04:29 +0200 Leon Romanovsky wrote: > > > > > Please fix nsim instead of devlink. > > > > I think if devlink is not registered, it can not be get and used, but there > > > > is no API for driver to check this, can I introduce a new helper name > > > > devlink_is_registered() for driver using. > > > There is no need in such API as driver calls to devlink_register() and > > > as such it knows when devlink is registered. > > > > > > This UAF is nsim specific issue. Real devices have single .probe() > > > routine with serialized registration flow. None of them will use > > > devlink_is_registered() call. > > Agreed, the fix is to move the register call back. > > Something along the lines of the untested patch below? > > Yang Yingliang would you be able to turn that into a real patch? > > > > diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c > > index e14686594a71..26602d5fe0a2 100644 > > --- a/drivers/net/netdevsim/dev.c > > +++ b/drivers/net/netdevsim/dev.c > > @@ -1566,12 +1566,15 @@ int nsim_drv_probe(struct nsim_bus_dev *nsim_bus_dev) > > err = devlink_params_register(devlink, nsim_devlink_params, > > ARRAY_SIZE(nsim_devlink_params)); > > if (err) > > - goto err_dl_unregister; > > + goto err_resource_unregister; > > nsim_devlink_set_params_init_values(nsim_dev, devlink); > > + /* here, because params API still expect devlink to be unregistered */ > > + devl_register(devlink); > > + > devlink_set_features() called at last in probe() also needs devlink is not > registered. > > err = nsim_dev_dummy_region_init(nsim_dev, devlink); > > if (err) > > - goto err_params_unregister; > > + goto err_dl_unregister; > > err = nsim_dev_traps_init(devlink); > > if (err) > > @@ -1610,7 +1613,6 @@ int nsim_drv_probe(struct nsim_bus_dev *nsim_bus_dev) > > nsim_dev->esw_mode = DEVLINK_ESWITCH_MODE_LEGACY; > > devlink_set_features(devlink, DEVLINK_F_RELOAD); > > devl_unlock(devlink); > > - devlink_register(devlink); > > return 0; > > err_hwstats_exit: > > @@ -1629,10 +1631,11 @@ int nsim_drv_probe(struct nsim_bus_dev *nsim_bus_dev) > > nsim_dev_traps_exit(devlink); > > err_dummy_region_exit: > > nsim_dev_dummy_region_exit(nsim_dev); > > -err_params_unregister: > > +err_dl_unregister: > > + devl_unregister(devlink); > It races with dev_ethtool(): > dev_ethtool >   devlink_try_get() >                                 nsim_drv_probe >                                 devl_lock() >     devl_lock() >                                 devlink_unregister() >                                   devlink_put() >                                   wait_for_completion() <- the refcount is > got in dev_ethtool, it causes ABBA deadlock But all these races are nsim specific ones. Can you please explain why devlink.[c|h] MUST be changed and nsim can't be fixed? Thanks