Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751501AbdFETYx (ORCPT ); Mon, 5 Jun 2017 15:24:53 -0400 Received: from lhrrgout.huawei.com ([194.213.3.17]:28041 "EHLO lhrrgout.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751077AbdFETYv (ORCPT ); Mon, 5 Jun 2017 15:24:51 -0400 From: Igor Stoppa To: , , CC: , , , , , , , , , Igor Stoppa Subject: [PATCH 4/5] Make LSM Writable Hooks a command line option Date: Mon, 5 Jun 2017 22:22:15 +0300 Message-ID: <20170605192216.21596-5-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170605192216.21596-1-igor.stoppa@huawei.com> References: <20170605192216.21596-1-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.5935AFE8.023F,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: 2794e6790e21df5aa093cdd7552cbdc1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2909 Lines: 104 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. Signed-off-by: Igor Stoppa CC: Tetsuo Handa --- init/main.c | 2 ++ security/security.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/init/main.c b/init/main.c index f866510..7850887 100644 --- a/init/main.c +++ b/init/main.c @@ -485,6 +485,7 @@ static void __init mm_init(void) ioremap_huge_init(); } +extern int __init pmalloc_init(void); asmlinkage __visible void __init start_kernel(void) { char *command_line; @@ -653,6 +654,7 @@ asmlinkage __visible void __init start_kernel(void) proc_caches_init(); buffer_init(); key_init(); + pmalloc_init(); security_init(); dbg_late_init(); vfs_caches_init(); diff --git a/security/security.c b/security/security.c index c492f68..4285545 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 security_debug; + +static __init int set_security_debug(char *str) +{ + get_option(&str, &security_debug); + return 0; +} +early_param("security_debug", set_security_debug); + +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 +69,13 @@ int __init security_init(void) { enum security_hook_index i; + sec_pool = pmalloc_create_pool("security"); + if (!sec_pool) + goto error_pool; + hook_heads = pmalloc(sizeof(struct list_head) * LSM_MAX_HOOK_INDEX, + sec_pool); + if (!hook_heads) + goto error_heads; for (i = 0; i < LSM_MAX_HOOK_INDEX; i++) INIT_LIST_HEAD(&hook_heads[i]); pr_info("Security Framework initialized\n"); @@ -74,8 +91,14 @@ int __init security_init(void) * Load all the remaining security modules. */ do_security_initcalls(); - + if (!security_debug) + pmalloc_protect_pool(sec_pool); return 0; + +error_heads: + pmalloc_destroy_pool(sec_pool); +error_pool: + return -ENOMEM; } /* Save user chosen LSM */ -- 2.9.3