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=-0.8 required=3.0 tests=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 BD9B2C11D00 for ; Thu, 20 Feb 2020 22:54:47 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 2038F206F4 for ; Thu, 20 Feb 2020 22:54:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2038F206F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17869-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 13874 invoked by uid 550); 20 Feb 2020 22:54:41 -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 13834 invoked from network); 20 Feb 2020 22:54:40 -0000 Date: Thu, 20 Feb 2020 22:54:20 +0000 From: Al Viro To: "Eric W. Biederman" Cc: Linus Torvalds , 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 Subject: Re: [PATCH 4/7] proc: Use d_invalidate in proc_prune_siblings_dcache Message-ID: <20200220225420.GR23230@ZenIV.linux.org.uk> References: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87blpt9e6m.fsf_-_@x220.int.ebiederm.org> Sender: Al Viro On Thu, Feb 20, 2020 at 02:49:53PM -0600, Eric W. Biederman wrote: > > The function d_prune_aliases has the problem that it will only prune > aliases thare are completely unused. It will not remove aliases for > the dcache or even think of removing mounts from the dcache. For that > behavior d_invalidate is needed. > > 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. s/no inode.*/it's a fucking directory inode./