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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 F06C8C47080 for ; Sun, 23 May 2021 20:26:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0BE46044F for ; Sun, 23 May 2021 20:26:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231939AbhEWU17 (ORCPT ); Sun, 23 May 2021 16:27:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231933AbhEWU16 (ORCPT ); Sun, 23 May 2021 16:27:58 -0400 Received: from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com [IPv6:2a00:1450:4864:20::32c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9558CC061574; Sun, 23 May 2021 13:26:31 -0700 (PDT) Received: by mail-wm1-x32c.google.com with SMTP id n17-20020a7bc5d10000b0290169edfadac9so430293wmk.1; Sun, 23 May 2021 13:26:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:references:from:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=PygufLx+GftT6TS2etBhgc6+uuLN9BWMi/zqgHpQvsY=; b=esrTniYlKVIz1qwncB0fA1f6EoaGdXdv9Byf2wrzoXpJoI8ojdqkT7UMYtQ9tQdySr dSSenwaL0uFN0kSScz4CSe6aF58av5EQOYX0crNgBe7TucIZqRPeRPClZzCZd7yi8vWW O8nk+31pXBR9ihIKwxvRsCSxf62JDvRBeSK/GiTZ2dw/RpQpabwMEsy6xgjhQ8CbfoP5 QLmJcJBTT4BYTPrUanoQCVObQvlzPbKoVnKLRz+H90+AnrvDsodYtO/tWjJExz5Adju5 /lQx48WoVzuaUsfWYwEcjGsVXZwjY1oR64OEuEmYacUMdOdrwAbXifj7z1hl61xv6RDW +kLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=PygufLx+GftT6TS2etBhgc6+uuLN9BWMi/zqgHpQvsY=; b=gLXj6Ac2l8Z0G8Ix7wJnc9AgD1h16l/ooQAG8LPDBLhJRKDmTde+2jT9rWquNdmVn3 Md7APd2kH4SdX6St8WqxD7yMXx9Iten6ufr0VHC0WGQkIyW5Ak8f8C/uoMhZzmaR2tiB 6JItb7srFisF6oH6TE6C7ItzXHlE/OdaVqhaw3IEYSOHnGDQu757ijliAYkJ2JSsU2xn uzHPjXOKYNo0Ze9KarabMK5jOFoIqx0ksVb8ZB3eby68thNsFxg8Ca0W+8cEWMduPzWi /4EBFZBbJnzbXuwgOftwH1hB7GwDjzgecb4o8aXEi+yc+eu1LziUfp1TvNfE/Dpeviem txuA== X-Gm-Message-State: AOAM530hZhyBzj4zpbyxDDarbQ2COhHDISIQ/FtVtmVQ8RfG+EpucDLj GXs5F+cF11eqJSCVw6prF00F51Z0/rE0jefX X-Google-Smtp-Source: ABdhPJwHSQNM+a1cD2dybYGpeqrMJbBTrEBwBzdhWHyWUNWiVsmNBtsEauiH5obSA1GKRpi7NeXYOw== X-Received: by 2002:a1c:4b13:: with SMTP id y19mr17332089wma.102.1621801590115; Sun, 23 May 2021 13:26:30 -0700 (PDT) Received: from [192.168.8.197] ([185.69.145.65]) by smtp.gmail.com with ESMTPSA id 11sm5855772wmo.24.2021.05.23.13.26.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 23 May 2021 13:26:29 -0700 (PDT) To: Paul Moore Cc: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-audit@redhat.com, io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Kumar Kartikeya Dwivedi , Jens Axboe , Alexander Viro References: <162163367115.8379.8459012634106035341.stgit@sifl> <162163379461.8379.9691291608621179559.stgit@sifl> From: Pavel Begunkov Subject: Re: [RFC PATCH 2/9] audit,io_uring,io-wq: add some basic audit support to io_uring Message-ID: <162219f9-7844-0c78-388f-9b5c06557d06@gmail.com> Date: Sun, 23 May 2021 21:26:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 5/22/21 3:36 AM, Paul Moore wrote: > On Fri, May 21, 2021 at 8:22 PM Pavel Begunkov wrote: >> On 5/21/21 10:49 PM, Paul Moore wrote: [...] >>> >>> + if (req->opcode < IORING_OP_LAST) >> >> always true at this point > > I placed the opcode check before the audit call because the switch > statement below which handles the operation dispatching has a 'ret = > -EINVAL' for the default case, implying that there are some paths > where an invalid opcode could be passed into the function. Obviously > if that is not the case and you can guarantee that req->opcode will > always be valid we can easily drop the check prior to the audit call. It is always true at this point, would be completely broken otherwise >>> + audit_uring_entry(req->opcode); >> >> So, it adds two if's with memory loads (i.e. current->audit_context) >> per request in one of the hottest functions here... No way, nack >> >> Maybe, if it's dynamically compiled into like kprobes if it's >> _really_ used. > > I'm open to suggestions on how to tweak the io_uring/audit > integration, if you don't like what I've proposed in this patchset, > lets try to come up with a solution that is more palatable. If you > were going to add audit support for these io_uring operations, how > would you propose we do it? Not being able to properly audit io_uring > operations is going to be a significant issue for a chunk of users, if > it isn't already, we need to work to find a solution to this problem. Who knows. First of all, seems CONFIG_AUDIT is enabled by default for many popular distributions, so I assume that is not compiled out. What are use cases for audit? Always running I guess? Putting aside compatibility problems, it sounds that with the amount of overhead it adds there is no much profit in using io_uring in the first place. Is that so? __audit_uring_exit() -> audit_filter_syscall() -> for (audit_list) if (...) audit_filter_rules() -> ... -> audit_filter_inodes() -> ... > Unfortunately I don't think dynamically inserting audit calls is > something that would meet the needs of the audit community (I fear it > would run afoul of the various security certifications), and it > definitely isn't something that we support at present. I see -- Pavel Begunkov