From patchwork Tue Jun 27 17:33:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 9812863 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5BA5160351 for ; Tue, 27 Jun 2017 17:36:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 45AAE26E98 for ; Tue, 27 Jun 2017 17:36:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3A69C28179; Tue, 27 Jun 2017 17:36:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 97580274A3 for ; Tue, 27 Jun 2017 17:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803AbdF0Rg2 (ORCPT ); Tue, 27 Jun 2017 13:36:28 -0400 Received: from lhrrgout.huawei.com ([194.213.3.17]:29383 "EHLO lhrrgout.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752396AbdF0Rg1 (ORCPT ); Tue, 27 Jun 2017 13:36:27 -0400 Received: from 172.18.7.190 (EHLO LHREML712-CAH.china.huawei.com) ([172.18.7.190]) by lhrrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DJH25988; Tue, 27 Jun 2017 17:36:22 +0000 (GMT) Received: from localhost.localdomain (10.122.225.51) by smtpsuk.huawei.com (10.201.108.35) with Microsoft SMTP Server (TLS) id 14.3.301.0; Tue, 27 Jun 2017 18:36:12 +0100 From: Igor Stoppa To: , , CC: , , , , , , , , , , Igor Stoppa , Igor Stoppa Subject: [PATCH 3/3] Make LSM Writable Hooks a command line option Date: Tue, 27 Jun 2017 20:33:23 +0300 Message-ID: <20170627173323.11287-4-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170627173323.11287-1-igor.stoppa@huawei.com> References: <20170627173323.11287-1-igor.stoppa@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.59529798.018A, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: d451244ec20565f07ffb4fc9c9289434 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Igor Stoppa This patch shows how it is possible to take advantage of pmalloc: instead of using the build-time option __lsm_ro_after_init, to decide if it is possible to keep the hooks modifiable, now this becomes a boot-time decision, based on the kernel command line. This patch relies on: "Convert security_hook_heads into explicit array of struct list_head" Author: Tetsuo Handa to break free from the static constraint imposed by the previous hardening model, based on __ro_after_init. The default value is disabled, unless SE Linux debugging is turned on. Signed-off-by: Igor Stoppa CC: Tetsuo Handa --- security/security.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/security/security.c b/security/security.c index 44c47b6..c7b4670 100644 --- a/security/security.c +++ b/security/security.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #define MAX_LSM_EVM_XATTR 2 @@ -34,10 +35,19 @@ /* Maximum number of letters for an LSM name string */ #define SECURITY_NAME_MAX 10 -static struct list_head hook_heads[LSM_MAX_HOOK_INDEX] - __lsm_ro_after_init; static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain); +static int dynamic_lsm = IS_ENABLED(CONFIG_SECURITY_SELINUX_DISABLE); + +static __init int set_dynamic_lsm(char *str) +{ + get_option(&str, &dynamic_lsm); + return 0; +} +early_param("dynamic_lsm", set_dynamic_lsm); + +static struct list_head *hook_heads; +static struct gen_pool *sec_pool; char *lsm_names; /* Boot-time LSM user choice */ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = @@ -62,6 +72,11 @@ int __init security_init(void) { enum security_hook_index i; + sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER); + BUG_ON(!sec_pool); + hook_heads = pmalloc(sec_pool, + sizeof(struct list_head) * LSM_MAX_HOOK_INDEX); + BUG_ON(!hook_heads); for (i = 0; i < LSM_MAX_HOOK_INDEX; i++) INIT_LIST_HEAD(&hook_heads[i]); pr_info("Security Framework initialized\n"); @@ -77,7 +92,8 @@ int __init security_init(void) * Load all the remaining security modules. */ do_security_initcalls(); - + if (!dynamic_lsm) + pmalloc_protect_pool(sec_pool); return 0; }