From patchwork Wed Oct 4 22:09:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fan Wu X-Patchwork-Id: 13409538 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 DFEF1E936F6 for ; Wed, 4 Oct 2023 22:10:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235054AbjJDWKF (ORCPT ); Wed, 4 Oct 2023 18:10:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231594AbjJDWJz (ORCPT ); Wed, 4 Oct 2023 18:09:55 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F3E82DD; Wed, 4 Oct 2023 15:09:50 -0700 (PDT) Received: by linux.microsoft.com (Postfix, from userid 1052) id 4ECF020B74C6; Wed, 4 Oct 2023 15:09:50 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4ECF020B74C6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1696457390; bh=jGkhEn3ZFwR/GgtoddxjP0SkUVW+MWODAqAxLOOgeiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nuhx3tGLEpT1yj9wFPQtNUAp58mBUdu6GBUGTyQanRtHBOjkklh16yYhfT9aY0gZ6 huOxUMcbhYESb6WW6vXHU/8mSbvsqk89Rk2fl2wtXbNFAmFLSjD1JGmX36qdulk0db U3zyyXu0wECnsvsnkjfsa1e7L/jMxHR89VyWuDh0= From: Fan Wu To: 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, paul@paul-moore.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: [RFC PATCH v11 03/19] ipe: add evaluation loop Date: Wed, 4 Oct 2023 15:09:30 -0700 Message-Id: <1696457386-3010-4-git-send-email-wufan@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1696457386-3010-1-git-send-email-wufan@linux.microsoft.com> References: <1696457386-3010-1-git-send-email-wufan@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Deven Bowers 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/Makefile b/security/ipe/Makefile index c09aec4904f2..57fe922cf1fc 100644 --- a/security/ipe/Makefile +++ b/security/ipe/Makefile @@ -6,6 +6,7 @@ # obj-$(CONFIG_SECURITY_IPE) += \ + eval.o \ ipe.o \ policy.o \ policy_parser.o \ 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; + 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); + 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; +} diff --git a/security/ipe/eval.h b/security/ipe/eval.h new file mode 100644 index 000000000000..6b434515968f --- /dev/null +++ b/security/ipe/eval.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_EVAL_H +#define _IPE_EVAL_H + +#include +#include + +#include "policy.h" + +extern struct ipe_policy __rcu *ipe_active_policy; + +struct ipe_eval_ctx { + enum ipe_op_type op; + + const struct file *file; +}; + +int ipe_evaluate_event(const struct ipe_eval_ctx *const ctx); + +#endif /* _IPE_EVAL_H */