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 68D46ECAAA1 for ; Mon, 19 Sep 2022 17:35:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231238AbiISRfw (ORCPT ); Mon, 19 Sep 2022 13:35:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231392AbiISRfh (ORCPT ); Mon, 19 Sep 2022 13:35:37 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE7E742AD1 for ; Mon, 19 Sep 2022 10:35:36 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id b75so285678pfb.7 for ; Mon, 19 Sep 2022 10:35:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date; bh=HuIbR7/ykiRWb44NTEFpaX0ksPF00/slbuNRkuNnZs0=; b=XzXdG+HT7Z2Fcj1whEzjVz0+JJeYSqZ1o95SbEZqWj249JjKXuUsIv+t7ppf2Upe6G ZIVMB6MvQMApvcHiYBmD9jvNSuRVz18cD6UEu/gX4Xq303Pcr+/OrGvuggEQqzoX0Gjo JY/AZY6BsShLOECUkEh5Wgtp1/9t+ewXhrd3+8M4v3skdyRH/zwsd4yXb69TT7fxVsWU d5zOsR5Ess21X9npTOekfXDC0reuVYIJyMrSJ8FUZ+OcCKnNu9tzeMccFW3mbW66mnDh koAc6W8h9y3MC8qJU1PjX3R8yX1of/YpzSTtm01Ax66V0+RtR9R9iGCZNblHXtx3X1Ie QsIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date; bh=HuIbR7/ykiRWb44NTEFpaX0ksPF00/slbuNRkuNnZs0=; b=O+ssTtEfem820bBd5gCpbVzpH+TDT4SFe9IXftvcVHsFq1RcBg/R17//Lt9Fo6+/Bu smuYfQ7tXcjg3cYQ8SkH02RvZCNMqfXRocCB5kRY4AaROY7HesFwMj5iEuDkthCcr+9T f6S263LGH7Jsz00897q+A9mRuEI9UgXQ43oRK4Y7acRiPJgNNroCYGumt4HLJeDOusSU a5OuTh0xE6hrZQ9UD9/sYP+xLrmqoHQL2OnQqH5EzRA8ii99wHWaqfgirthoFLuJQnrz x0v95uKxcZ3T56RikOVwb26uE52JonYPy1yhf/ZXrcQ+IpNz7SaA1xc/TzhCS11298RF DVXA== X-Gm-Message-State: ACrzQf31YT3gRLOdrkGJ3xCNC9S3vK5Rtl1T4lXl3MgwyihB1D8Ns1Ho kDa9FUAoCf7WnLSekV21oe7MZ9N3BgnPfw== X-Google-Smtp-Source: AMsMyM5/h6Hb8n+oTsWerH7KYegujzSE+mS3NtqLVwtPpxf/59p9EJqAWNegoaW1ehRh+W81Txjq+g== X-Received: by 2002:a05:6a00:2402:b0:52c:81cf:8df2 with SMTP id z2-20020a056a00240200b0052c81cf8df2mr19569562pfh.40.1663608935977; Mon, 19 Sep 2022 10:35:35 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id j15-20020a170903024f00b00176d6ad3cd4sm20317667plh.100.2022.09.19.10.35.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Sep 2022 10:35:35 -0700 (PDT) Sender: Tejun Heo Date: Mon, 19 Sep 2022 07:35:34 -1000 From: Tejun Heo To: "Christian A. Ehrhardt" Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman Subject: Re: [PATCH v2] kernfs: fix use-after-free in __kernfs_remove Message-ID: References: <20220913121723.691454-1-lk@c--e.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220913121723.691454-1-lk@c--e.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 13, 2022 at 02:17:23PM +0200, Christian A. Ehrhardt wrote: > Syzkaller managed to trigger concurrent calls to > kernfs_remove_by_name_ns() for the same file resulting in > a KASAN detected use-after-free. The race occurs when the root > node is freed during kernfs_drain(). > > To prevent this acquire an additional reference for the root > of the tree that is removed before calling __kernfs_remove(). ... > cc: Greg Kroah-Hartman > cc: Tejun Heo > Signed-off-by: Christian A. Ehrhardt Acked-by: Tejun Heo Thanks. -- tejun