From patchwork Mon Jun 5 19:22:15 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 9767333 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 13E0E60353 for ; Mon, 5 Jun 2017 19:25:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 03C0124B5B for ; Mon, 5 Jun 2017 19:25:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EC76F27DCD; Mon, 5 Jun 2017 19:25:08 +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 24C6524B5B for ; Mon, 5 Jun 2017 19:25:07 +0000 (UTC) Received: (qmail 15383 invoked by uid 550); 5 Jun 2017 19:25:04 -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 14261 invoked from network); 5 Jun 2017 19:25:03 -0000 From: Igor Stoppa To: , , CC: , , , , , , , , , Igor Stoppa 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 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 Subject: [kernel-hardening] [PATCH 4/5] 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. 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 */