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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21593C433B4 for ; Tue, 11 May 2021 16:41:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3A0C61182 for ; Tue, 11 May 2021 16:41:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231645AbhEKQmq (ORCPT ); Tue, 11 May 2021 12:42:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230484AbhEKQmn (ORCPT ); Tue, 11 May 2021 12:42:43 -0400 Received: from mail-io1-xd32.google.com (mail-io1-xd32.google.com [IPv6:2607:f8b0:4864:20::d32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41876C061574; Tue, 11 May 2021 09:41:37 -0700 (PDT) Received: by mail-io1-xd32.google.com with SMTP id z24so18802173ioj.7; Tue, 11 May 2021 09:41:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=NAcAMBeXB+UzEqIBR9PQ8N01qh7SBVFQTz/pGB60gzc=; b=tfUP4XE3SfvyUX5EtSsWF9b+hMkqCy3qdlYKBIthHo/JF+Rapwovp/kPe4/efexjVj 79sEFyVzFwaIpAlCTYOX1tSl3wS8MJjb6s7pyReU39zWctZPRS8Vy0nTtjFbPGqgkMCu 5zpfUJpsSxqIvg4QUTBeHXX4eHmKhoIHFbP//of+9ymErtN3FwY/jGlrnq0VJOMGsL6l od+K1bx8MkSdRGd8D/VV07Jwd5st98ciKHG7NZkeIIiNMvW8cA4C9sEH0DGoNvrFxTEF KkwFYZOjynPXoRpMAJvlNnv1wleCPPuRt8oJ1ma6J86usj1IuZSOEHpu8OQysa0rGABX K8pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=NAcAMBeXB+UzEqIBR9PQ8N01qh7SBVFQTz/pGB60gzc=; b=dBAYVlgz90J5hJh9MaWUL0G675KkR3jMtVx6o2+ACdz9LRIW5vrH5T8Bn0FacjVXu/ 9JJKYts9cAmzS/irhbFAoDaVzS/XfxUVZ84R8DaU+EY3EUJK5fHvec2JZ5wb+nXuSfRC VNub53/CpY4FsawQKCjYwqXcKDX8lDXcSrRU0of48Tsic7Y6tfABOX6Kansw5TY0o3vo 2Db+rrgJkqoDXcyKMBdyRnfi12CZ7vCGItest4GIvEnDGtRt0SMzJYSNhEedk7UIziGn qqhWeqIPhO+whhie7NdJTspH2PMMd7gJrbLaX0cLMn5WVwsD7l8dtxQ25WAsOjtmahIt kNXA== X-Gm-Message-State: AOAM533URzvUlBfy5vT9wHhXPfvLXHxJlf015hqGQ+YgGY5mWrvcIp9o Xo/pUhsEqrJsTHki94JrJd8IpTU1JkqQzAda20k= X-Google-Smtp-Source: ABdhPJwQ8hOvK6/ojNkBTIZdILBedIs7PGErIHw1yqu5tVcZrYFKExLBT7TX/WkPQHh47ORMFginvAzSWDYfuGNGy/E= X-Received: by 2002:a05:6638:3013:: with SMTP id r19mr28198356jak.36.1620751296655; Tue, 11 May 2021 09:41:36 -0700 (PDT) MIME-Version: 1.0 References: <20210509215416.950337-1-ztong0001@gmail.com> In-Reply-To: From: Tong Zhang Date: Tue, 11 May 2021 09:41:26 -0700 Message-ID: Subject: Re: [PATCH] memstick: rtsx_usb_ms: fix UAF To: Ulf Hansson Cc: Maxim Levitsky , Alex Dubov , linux-mmc , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 11, 2021 at 3:40 AM Ulf Hansson wrote: > > On Sun, 9 May 2021 at 23:54, Tong Zhang wrote: > > > > This patch fixes the following issues: > > 1. memstick_free_host() will free the host, so the use of ms_dev(host) after > > it will be a problem. To fix this, move memstick_free_host() after when we > > are done with ms_dev(host). > > 2. if something bad happens in memstick_add_host() and we end up taking > > err_out in rtsx_usb_ms_drv_probe(), we'd better avoid running rtsx_usb_ms_drv_remove() > > If the ->probe() function returns a negative error code, the driver > core will not invoke the corresponding ->remove() callback. > > Looks like you may want to double check that ->probe() doesn't return > 0, even in case of failure. > > > 3. In rtsx_usb_ms_drv_remove(), pm need to be disabled before we remove > > and free host otherwise memstick_check will be called and UAF will > > happen. > > > > [ 11.351173] BUG: KASAN: use-after-free in rtsx_usb_ms_drv_remove+0x94/0x140 [rtsx_usb_ms] > > [ 11.357077] rtsx_usb_ms_drv_remove+0x94/0x140 [rtsx_usb_ms] > > [ 11.357376] platform_remove+0x2a/0x50 > > [ 11.367531] Freed by task 298: > > [ 11.368537] kfree+0xa4/0x2a0 > > [ 11.368711] device_release+0x51/0xe0 > > [ 11.368905] kobject_put+0xa2/0x120 > > [ 11.369090] rtsx_usb_ms_drv_remove+0x8c/0x140 [rtsx_usb_ms] > > [ 11.369386] platform_remove+0x2a/0x50 > > > > [ 12.038408] BUG: KASAN: use-after-free in __mutex_lock.isra.0+0x3ec/0x7c0 > > [ 12.045432] mutex_lock+0xc9/0xd0 > > [ 12.046080] memstick_check+0x6a/0x578 [memstick] > > [ 12.046509] process_one_work+0x46d/0x750 > > [ 12.052107] Freed by task 297: > > [ 12.053115] kfree+0xa4/0x2a0 > > [ 12.053272] device_release+0x51/0xe0 > > [ 12.053463] kobject_put+0xa2/0x120 > > [ 12.053647] rtsx_usb_ms_drv_remove+0xc4/0x140 [rtsx_usb_ms] > > [ 12.053939] platform_remove+0x2a/0x50 > > > > Signed-off-by: Tong Zhang > > --- > > drivers/memstick/host/rtsx_usb_ms.c | 13 +++++++------ > > 1 file changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c > > index 102dbb8080da..851643d007b7 100644 > > --- a/drivers/memstick/host/rtsx_usb_ms.c > > +++ b/drivers/memstick/host/rtsx_usb_ms.c > > @@ -799,9 +799,10 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev) > > > > return 0; > > err_out: > > - memstick_free_host(msh); > > pm_runtime_disable(ms_dev(host)); > > pm_runtime_put_noidle(ms_dev(host)); > > + memstick_free_host(msh); > > + platform_set_drvdata(pdev, NULL); > > return err; > > } > > > > @@ -811,6 +812,8 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) > > struct memstick_host *msh = host->msh; > > int err; > > > > + if (!host) > > + return 0; > > According to my comment above. You should not reach this point, unless > ->probe() was successful and returned 0. > > > host->eject = true; > > cancel_work_sync(&host->handle_req); > > > > @@ -828,9 +831,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) > > } > > mutex_unlock(&host->host_mutex); > > > > - memstick_remove_host(msh); > > - memstick_free_host(msh); > > - > > /* Balance possible unbalanced usage count > > * e.g. unconditional module removal > > */ > > @@ -838,10 +838,11 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) > > pm_runtime_put(ms_dev(host)); > > > > pm_runtime_disable(ms_dev(host)); > > - platform_set_drvdata(pdev, NULL); > > - > > + memstick_remove_host(msh); > > dev_dbg(ms_dev(host), > > ": Realtek USB Memstick controller has been removed\n"); > > + memstick_free_host(msh); > > + platform_set_drvdata(pdev, NULL); > > > > return 0; > > } > > -- > > 2.25.1 > > > > Besides the above, the change looks reasonable to me. > > Kind regards > Uffe Thanks Uffe! I modified the patch as suggested and sent as v2. Best, - Tong