From patchwork Wed Jun 7 12:35:05 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 9771491 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 91D3260364 for ; Wed, 7 Jun 2017 12:39:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7E936284A8 for ; Wed, 7 Jun 2017 12:39:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 733CA284CF; Wed, 7 Jun 2017 12:39:03 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 79915284A8 for ; Wed, 7 Jun 2017 12:39:02 +0000 (UTC) Received: (qmail 32051 invoked by uid 550); 7 Jun 2017 12:39:00 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 32017 invoked from network); 7 Jun 2017 12:39:00 -0000 From: Igor Stoppa To: , , CC: , , , , , , , , , , Igor Stoppa Date: Wed, 7 Jun 2017 15:35:05 +0300 Message-ID: <20170607123505.16629-5-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170607123505.16629-1-igor.stoppa@huawei.com> References: <20170607123505.16629-1-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=0001.0A020201.5937F3CE.012D, 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: 26c0726b44bddf297296ab50ab076386 Subject: [kernel-hardening] [PATCH 4/4] Make LSM Writable Hooks a command line option X-Virus-Scanned: ClamAV using ClamSMTP 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 c492f68..9b8b478 100644 --- a/security/security.c +++ b/security/security.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #define MAX_LSM_EVM_XATTR 2 @@ -33,8 +34,17 @@ /* 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 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 pmalloc_pool *sec_pool; char *lsm_names; /* Boot-time LSM user choice */ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = @@ -59,6 +69,11 @@ int __init security_init(void) { enum security_hook_index i; + sec_pool = pmalloc_create_pool("security"); + BUG_ON(!sec_pool); + hook_heads = pmalloc(sizeof(struct list_head) * LSM_MAX_HOOK_INDEX, + sec_pool); + 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"); @@ -74,7 +89,8 @@ int __init security_init(void) * Load all the remaining security modules. */ do_security_initcalls(); - + if (!dynamic_lsm) + pmalloc_protect_pool(sec_pool); return 0; }