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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 274FCC11D00 for ; Thu, 20 Feb 2020 22:44:14 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 77442207FD for ; Thu, 20 Feb 2020 22:44:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HocGqZaP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77442207FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17868-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 5985 invoked by uid 550); 20 Feb 2020 22:44:08 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 5962 invoked from network); 20 Feb 2020 22:44:07 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=IsBAqEZQag0ypHqg0PyTqrCBxrLtLK/vf3m5Pbo+Q1I=; b=HocGqZaPvPbj2Rc3tHfIsXtvsU9ZExNqDhyGTd1FkLfg2CixXSIhWg+lhtFLFy7LH5 Ll9ajjeSCLGyVGJFCP3pr8MzRIUlhdaSf4zT2trYK3NmUY7kfmF8q56qyO7AFc70i6vi mx1gRvncgXwtZTQp0OujHwfoGsQovufSXPaY4= 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=IsBAqEZQag0ypHqg0PyTqrCBxrLtLK/vf3m5Pbo+Q1I=; b=ADw3aab4yuJs/tIXKodda9CG6YIJ3HJZGpaTP2qgpcVzgMh3ciqD9/ErWc2OYJlik3 fnfhJcsoIIpV+prjfub48iu4lOBBkCJE4rpdv6fEgXDzfWR2ey+MH8mklm5AeypPtBaQ sMChkPEhPng8UMMQs7zpVP0pDjhYURUb4Q7d2/FeuC9/ehR2dRZKhCRMJADvFgKOo4vR c5+FP/1doMa1vnAz70iGRinfzk2tcOkGf54IlJAodUctMuewB3WUXfRc83wUM/mNiNt7 luT2tcxS0N7S9L6ent86Kgrafwk38OEjpJyWQYI+Zydu25fB0UWeMPySHu6HuPaMuMDy OSAA== X-Gm-Message-State: APjAAAW6B+w4MKOJYww9IdtkDoNuKnQIaaLEpzZ+fKZ/XvNFDEy7kUZt cq/N2nU1rRfvvueAcvrwT/RaH/EWBbQ= X-Google-Smtp-Source: APXvYqzeODsYUSUEi5juXEbc+W82/i/md/9CARls1oEpBp5nZAP8ZtRFcDBWL7gMVzSWSYd8VKga1g== X-Received: by 2002:a05:6512:31c3:: with SMTP id j3mr2575724lfe.144.1582238635354; Thu, 20 Feb 2020 14:43:55 -0800 (PST) X-Received: by 2002:a2e:88c5:: with SMTP id a5mr20465844ljk.201.1582238633679; Thu, 20 Feb 2020 14:43:53 -0800 (PST) MIME-Version: 1.0 References: <20200210150519.538333-8-gladkov.alexey@gmail.com> <87v9odlxbr.fsf@x220.int.ebiederm.org> <20200212144921.sykucj4mekcziicz@comp-core-i7-2640m-0182e6> <87tv3vkg1a.fsf@x220.int.ebiederm.org> <87v9obipk9.fsf@x220.int.ebiederm.org> <20200212200335.GO23230@ZenIV.linux.org.uk> <20200212203833.GQ23230@ZenIV.linux.org.uk> <20200212204124.GR23230@ZenIV.linux.org.uk> <87lfp7h422.fsf@x220.int.ebiederm.org> <87pnejf6fz.fsf@x220.int.ebiederm.org> <871rqpaswu.fsf_-_@x220.int.ebiederm.org> <87blpt9e6m.fsf_-_@x220.int.ebiederm.org> In-Reply-To: <87blpt9e6m.fsf_-_@x220.int.ebiederm.org> From: Linus Torvalds Date: Thu, 20 Feb 2020 14:43:38 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 4/7] proc: Use d_invalidate in proc_prune_siblings_dcache To: "Eric W. Biederman" Cc: Al Viro , LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module , Akinobu Mita , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Oleg Nesterov , Solar Designer Content-Type: text/plain; charset="UTF-8" On Thu, Feb 20, 2020 at 12:51 PM Eric W. Biederman wrote: > > To use d_invalidate replace d_prune_aliases with d_find_alias > followed by d_invalidate and dput. This is safe and complete > because no inode in proc has any hardlinks or aliases. Are you sure you can't create them some way? This makes em go "what if we had multiple dentries associated with that inode?" Then the code would just invalidate the first one. I guess we don't have export_operations or anything like that, but this makes me worry... Linus