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 417A1C38142 for ; Sat, 28 Jan 2023 16:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234600AbjA1Qt6 (ORCPT ); Sat, 28 Jan 2023 11:49:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234595AbjA1Qt4 (ORCPT ); Sat, 28 Jan 2023 11:49:56 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 579262917D for ; Sat, 28 Jan 2023 08:49:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674924542; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vJMl8Ly6KyE2eDx8S+bXIL1Y4voAlHQIMFALhv1I/e8=; b=VGwyWLM8aowmU+qfcM9igXxgGUkmFfe4JSpDtEd1+KXllHR44CiYT2W37Qtz/Zy0lea0IR 0ZTJcdpwNu23wkqNW9xaknV9q3xmjGaF1MpJoBBf8X0UIsxS2edwmESzzNEpYOYDaOD7U1 1PuWjEVd3f8wW6xm+u9qV3LRVbv+gu0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-56-dXy7C1ExPIuFHXVj3GmBzg-1; Sat, 28 Jan 2023 11:48:57 -0500 X-MC-Unique: dXy7C1ExPIuFHXVj3GmBzg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CD1D62A59542; Sat, 28 Jan 2023 16:48:56 +0000 (UTC) Received: from x2.localnet (unknown [10.22.8.91]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4C5D514171BE; Sat, 28 Jan 2023 16:48:56 +0000 (UTC) From: Steve Grubb To: Jens Axboe , Paul Moore Cc: Richard Guy Briggs , Linux-Audit Mailing List , LKML , io-uring@vger.kernel.org, Eric Paris , Stefan Roesch , Christian Brauner , Pavel Begunkov Subject: Re: [PATCH v1 1/2] io_uring,audit: audit IORING_OP_FADVISE but not IORING_OP_MADVISE Date: Sat, 28 Jan 2023 11:48:55 -0500 Message-ID: <5911706.lOV4Wx5bFT@x2> Organization: Red Hat In-Reply-To: References: <6d3f76ae-9f86-a96e-d540-cfd45475e288@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Friday, January 27, 2023 5:57:30 PM EST Paul Moore wrote: > On Fri, Jan 27, 2023 at 5:45 PM Jens Axboe wrote: > > On 1/27/23 3:35?PM, Paul Moore wrote: > > > On Fri, Jan 27, 2023 at 12:24 PM Richard Guy Briggs wrote: > > >> Since FADVISE can truncate files and MADVISE operates on memory, > > >> reverse > > >> the audit_skip tags. > > >> > > >> Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit > > >> support to io_uring") Signed-off-by: Richard Guy Briggs > > >> > > >> --- > > >> > > >> io_uring/opdef.c | 2 +- > > >> 1 file changed, 1 insertion(+), 1 deletion(-) > > >> > > >> diff --git a/io_uring/opdef.c b/io_uring/opdef.c > > >> index 3aa0d65c50e3..a2bf53b4a38a 100644 > > >> --- a/io_uring/opdef.c > > >> +++ b/io_uring/opdef.c > > >> @@ -306,12 +306,12 @@ const struct io_op_def io_op_defs[] = { > > >> > > >> }, > > >> [IORING_OP_FADVISE] = { > > >> > > >> .needs_file = 1, > > >> > > >> - .audit_skip = 1, > > >> > > >> .name = "FADVISE", > > >> .prep = io_fadvise_prep, > > >> .issue = io_fadvise, > > >> > > >> }, > > > > > > I've never used posix_fadvise() or the associated fadvise64*() > > > syscalls, but from quickly reading the manpages and the > > > generic_fadvise() function in the kernel I'm missing where the fadvise > > > family of functions could be used to truncate a file, can you show me > > > where this happens? The closest I can see is the manipulation of the > > > page cache, but that shouldn't actually modify the file ... right? > > > > Yeah, honestly not sure where that came from. Maybe it's being mixed up > > with fallocate? > > That was my thought too when I was looking at it. Oh. Yeah. fallocate is the one that truncates. fadvise can be skipped. -Steve > > All fadvise (or madvise, for that matter) does is > > provide hints on the caching or access pattern. On second thought, both > > of these should be able to set audit_skip as far as I can tell. > > Agreed on the fadvise side, and probably the madvise side too, > although the latter has more options/code to sift through so I'm > curious to hear what analysis Richard has done on that one.