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 782A2C25B6E for ; Tue, 24 Oct 2023 03:52:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232011AbjJXDwa (ORCPT ); Mon, 23 Oct 2023 23:52:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231982AbjJXDw3 (ORCPT ); Mon, 23 Oct 2023 23:52:29 -0400 Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2D59110 for ; Mon, 23 Oct 2023 20:52:24 -0700 (PDT) Received: by mail-qv1-xf35.google.com with SMTP id 6a1803df08f44-66cfef11a25so22055266d6.3 for ; Mon, 23 Oct 2023 20:52:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore.com; s=google; t=1698119544; x=1698724344; darn=vger.kernel.org; h=in-reply-to:references:subject:cc:to:from:message-id:date:from:to :cc:subject:date:message-id:reply-to; bh=tJ6cgsoW7aQH5On83YMhoiBwYYPuRYMOz8kgYTAfm70=; b=KAxMdUtDsdeg4dkTHCiRKRx2qzgP3I/YsfQWQAttZhThMMFHTachz+vuIDPFno0suJ cwCLtf0I2mh8lOvKs71uzJNM+UqepOh2T1+r/742NcxJSpobudmr+kgmqF/sBTNbUpKv FQAt2TGnMkJf3NGG5qHPee35ccZAwu8W/CS/pf2r/Jmnikc+QCq3ryUq9Ea9YBXLZZg2 lDo1fD7Tw4iV+XkbNYf9fj94VnCiNzMrlda2NMe7SY0HiT6fYAsNv47FuS48fdZQzIpy b5/TFB9Bsb1i6bGqfamWvXBThuTL0zClgBvKM/xReZdP4+8IIw5XqYWtn2rUrwHSwDME 2P/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698119544; x=1698724344; h=in-reply-to:references:subject:cc:to:from:message-id:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tJ6cgsoW7aQH5On83YMhoiBwYYPuRYMOz8kgYTAfm70=; b=JYkdpccqWQkb9vs/vGafj8iQGWhZlOShiKaRpSttl5OJan6tRm0/YWWqaglBM+AHai Ysh0BHJlcZVJlAzIsN8tzO85ADCK3NUxRXQDU91ITzrB2Grvpd9lAFb9XrkVu8WqqD2J avhINS+OBZe8fDLjqR/Z2zpliaqGw+SSd3Z6w3g9ipcoZjLThrByjiqnzi8nt8j9A3IY XDBPSVmrxenrHAwg7mVNHL0Phnf9RMn58yp2/n7w8pfASAtkPXGerKsIbRQu+uu0ML15 qhcXRussdLhhiActK14QGtvx8Wkj/YMQFm5qTB5nQeqm33zxKcaX9b2p2zGDb2ZwUzj9 HzOg== X-Gm-Message-State: AOJu0YzLFLpVE2i+ePwKiG+AIi/6t+C3kz4JzJf4xVXaQz/XIjpGBpcI QwL3T1weT1keX3p/ElLtmstR X-Google-Smtp-Source: AGHT+IEGJExcEmKWOA+GK4RiJy1dG9NUrijjKZKzwgQx3WaST0PHhoK9sXJHymPxgN5Fyv3kt+Yfmg== X-Received: by 2002:ad4:5cc2:0:b0:66d:169a:d41c with SMTP id iu2-20020ad45cc2000000b0066d169ad41cmr11857101qvb.19.1698119543857; Mon, 23 Oct 2023 20:52:23 -0700 (PDT) Received: from localhost ([70.22.175.108]) by smtp.gmail.com with ESMTPSA id i7-20020a37c207000000b0076db5b792basm3162304qkm.75.2023.10.23.20.52.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Oct 2023 20:52:23 -0700 (PDT) Date: Mon, 23 Oct 2023 23:52:22 -0400 Message-ID: From: Paul Moore To: Fan Wu , corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com, tytso@mit.edu, ebiggers@kernel.org, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org, eparis@redhat.com Cc: linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-block@vger.kernel.org, dm-devel@redhat.com, audit@vger.kernel.org, roberto.sassu@huawei.com, linux-kernel@vger.kernel.org, Deven Bowers , Fan Wu Subject: Re: [PATCH RFC v11 3/19] ipe: add evaluation loop References: <1696457386-3010-4-git-send-email-wufan@linux.microsoft.com> In-Reply-To: <1696457386-3010-4-git-send-email-wufan@linux.microsoft.com> Precedence: bulk List-ID: On Oct 4, 2023 Fan Wu wrote: > > IPE must have a centralized function to evaluate incoming callers > against IPE's policy. This iteration of the policy for against the rules > for that specific caller is known as the evaluation loop. > > Signed-off-by: Deven Bowers > Signed-off-by: Fan Wu > --- > v2: > + Split evaluation loop, access control hooks, and evaluation loop from policy parser and userspace interface to pass mailing list character limit > > v3: > + Move ipe_load_properties to patch 04. > + Remove useless 0-initializations Prefix extern variables with ipe_ > + Remove kernel module parameters, as these are exposed through sysctls. > + Add more prose to the IPE base config option help text. > + Use GFP_KERNEL for audit_log_start. > + Remove unnecessary caching system. > + Remove comments from headers > + Use rcu_access_pointer for rcu-pointer null check > + Remove usage of reqprot; use prot only. > +Move policy load and activation audit event to 03/12 > > v4: > + Remove sysctls in favor of securityfs nodes > + Re-add kernel module parameters, as these are now exposed through securityfs. > + Refactor property audit loop to a separate function. > > v5: > + fix minor grammatical errors > + do not group rule by curly-brace in audit record, > + reconstruct the exact rule. > > v6: > + No changes > > v7: > + Further split lsm creation into a separate commit from the evaluation loop and audit system, for easier review. > + Propagating changes to support the new ipe_context structure in the evaluation loop. > > v8: > + Remove ipe_hook enumeration; hooks can be correlated via syscall record. > > v9: > + Remove ipe_context related code and simplify the evaluation loop. > > v10: > + Split eval part and boot_verified part > > v11: > + Fix code style issues > --- > security/ipe/Makefile | 1 + > security/ipe/eval.c | 96 +++++++++++++++++++++++++++++++++++++++++++ > security/ipe/eval.h | 24 +++++++++++ > 3 files changed, 121 insertions(+) > create mode 100644 security/ipe/eval.c > create mode 100644 security/ipe/eval.h ... > diff --git a/security/ipe/eval.c b/security/ipe/eval.c > new file mode 100644 > index 000000000000..5533c359bbeb > --- /dev/null > +++ b/security/ipe/eval.c > @@ -0,0 +1,96 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) Microsoft Corporation. All rights reserved. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "ipe.h" > +#include "eval.h" > +#include "policy.h" > + > +struct ipe_policy __rcu *ipe_active_policy; > + > +/** > + * evaluate_property - Analyze @ctx against a property. > + * @ctx: Supplies a pointer to the context to be evaluated. > + * @p: Supplies a pointer to the property to be evaluated. > + * > + * Return: > + * * true - The current @ctx match the @p > + * * false - The current @ctx doesn't match the @p > + */ > +static bool evaluate_property(const struct ipe_eval_ctx *const ctx, > + struct ipe_prop *p) > +{ > + return false; > +} > + > +/** > + * ipe_evaluate_event - Analyze @ctx against the current active policy. > + * @ctx: Supplies a pointer to the context to be evaluated. > + * > + * This is the loop where all policy evaluation happens against IPE policy. > + * > + * Return: > + * * 0 - OK > + * * -EACCES - @ctx did not pass evaluation. > + * * !0 - Error > + */ > +int ipe_evaluate_event(const struct ipe_eval_ctx *const ctx) > +{ > + bool match = false; > + enum ipe_action_type action; > + struct ipe_policy *pol = NULL; > + const struct ipe_rule *rule = NULL; > + const struct ipe_op_table *rules = NULL; > + struct ipe_prop *prop = NULL; > + > + rcu_read_lock(); > + > + pol = rcu_dereference(ipe_active_policy); > + if (!pol) { > + rcu_read_unlock(); > + return 0; > + } > + > + if (ctx->op == IPE_OP_INVALID) { > + rcu_read_unlock(); > + if (pol->parsed->global_default_action == IPE_ACTION_DENY) > + return -EACCES; Assuming that the RCU lock protects @pol, shouldn't it be held until after the global_default_action comparison? > + return 0; > + } > + > + rules = &pol->parsed->rules[ctx->op]; > + > + list_for_each_entry(rule, &rules->rules, next) { > + match = true; > + > + list_for_each_entry(prop, &rule->props, next) { > + match = match && evaluate_property(ctx, prop); The @match variable will always be true on the right side above, or am I missing something? > + if (!match) > + break; > + } > + > + if (match) > + break; > + } > + > + if (match) > + action = rule->action; > + else if (rules->default_action != IPE_ACTION_INVALID) > + action = rules->default_action; > + else > + action = pol->parsed->global_default_action; > + > + rcu_read_unlock(); > + if (action == IPE_ACTION_DENY) > + return -EACCES; > + > + return 0; > +} -- paul-moore.com