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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 BB396C468BE for ; Mon, 10 Jun 2019 01:51:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A675206E0 for ; Mon, 10 Jun 2019 01:51:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730293AbfFJBvy (ORCPT ); Sun, 9 Jun 2019 21:51:54 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:50881 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729703AbfFJBvy (ORCPT ); Sun, 9 Jun 2019 21:51:54 -0400 Received: from callcc.thunk.org ([66.31.38.53]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x5A1pjIR002876 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 9 Jun 2019 21:51:46 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id C99A2420481; Sun, 9 Jun 2019 21:51:45 -0400 (EDT) Date: Sun, 9 Jun 2019 21:51:45 -0400 From: "Theodore Ts'o" To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/8] mm/fs: don't allow writes to immutable files Message-ID: <20190610015145.GB3266@mit.edu> References: <155552786671.20411.6442426840435740050.stgit@magnolia> <155552787330.20411.11893581890744963309.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <155552787330.20411.11893581890744963309.stgit@magnolia> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Apr 17, 2019 at 12:04:33PM -0700, Darrick J. Wong wrote: > diff --git a/mm/memory.c b/mm/memory.c > index ab650c21bccd..dfd5eba278d6 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2149,6 +2149,9 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) > > vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; > > + if (vmf->vma->vm_file && IS_IMMUTABLE(file_inode(vmf->vma->vm_file))) > + return VM_FAULT_SIGBUS; > + > ret = vmf->vma->vm_ops->page_mkwrite(vmf); > /* Restore original flags so that caller is not surprised */ > vmf->flags = old_flags; Shouldn't this check be moved before the modification of vmf->flags? It looks like do_page_mkwrite() isn't supposed to be returning with vmf->flags modified, lest "the caller gets surprised". - Ted