From patchwork Sat Jun 13 02:41:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11602449 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 75D25913 for ; Sat, 13 Jun 2020 02:41:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A46F2074B for ; Sat, 13 Jun 2020 02:41:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="SI8Fof/0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726290AbgFMClp (ORCPT ); Fri, 12 Jun 2020 22:41:45 -0400 Received: from linux.microsoft.com ([13.77.154.182]:54148 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726401AbgFMCli (ORCPT ); Fri, 12 Jun 2020 22:41:38 -0400 Received: from localhost.localdomain (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 1B5AA20B4783; Fri, 12 Jun 2020 19:41:37 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1B5AA20B4783 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1592016097; bh=9/oXutbjuzQ/I6R6w3F6z0lqsxijqgXEqgpbX21P2Gg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SI8Fof/01+jriFe6mbCZvsCy7DRxgq0daX7KNERJA0B7gG8NkhFxziMU1CQDJs8L+ Nwt+Vxz+YqUrlJcAOj9IE8pmD5AsR1FpNPHiGBuXBukB3rKJRMPc9sjh5krlzp7Z0i dPzpW8tS88pVhO90ZbSLIDX0WQnJfrGKHqzFsy1w= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, stephen.smalley@gmail.com, casey@schaufler-ca.com Cc: jmorris@namei.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/5] LSM: Define SELinux function to measure security state Date: Fri, 12 Jun 2020 19:41:29 -0700 Message-Id: <20200613024130.3356-5-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200613024130.3356-1-nramas@linux.microsoft.com> References: <20200613024130.3356-1-nramas@linux.microsoft.com> MIME-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org SELinux needs to implement the interface function, security_state(), for the LSM to gather SELinux data for measuring. Define the security_state() function in SELinux. The security modules should be able to notify the LSM when there is a change in the module's data. Define a function namely security_state_change() in the LSM that the security modules can call to provide the updated data for measurement. Call security_state_change() function from SELinux to report data when SELinux's state is updated. Signed-off-by: Lakshmi Ramasubramanian --- include/linux/lsm_hooks.h | 3 ++ security/security.c | 5 ++++ security/selinux/hooks.c | 43 +++++++++++++++++++++++++++++ security/selinux/include/security.h | 2 ++ security/selinux/selinuxfs.c | 1 + 5 files changed, 54 insertions(+) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index da248c3fd4ac..a63de046139e 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1572,6 +1572,9 @@ struct lsm_info { int *state_len); /*Optional */ }; +/* Called by LSMs to notify security state change */ +extern void security_state_change(char *lsm_name, void *state, int state_len); + extern struct lsm_info __start_lsm_info[], __end_lsm_info[]; extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[]; diff --git a/security/security.c b/security/security.c index a6e2d1cd95af..e7175db5a093 100644 --- a/security/security.c +++ b/security/security.c @@ -238,6 +238,11 @@ static void __init initialize_lsm(struct lsm_info *lsm) } } +void security_state_change(char *lsm_name, void *state, int state_len) +{ + ima_lsm_state(lsm_name, state, state_len); +} + static int measure_security_state(struct lsm_info *lsm) { char *lsm_name = NULL; diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 7e954b555be6..bbc908a1fcd1 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7225,6 +7225,47 @@ static __init int selinux_init(void) return 0; } +static int selinux_security_state(char **lsm_name, void **state, + int *state_len) +{ + int rc = 0; + char *new_state; + static char *security_state_string = "enabled=%d;enforcing=%d"; + + *lsm_name = kstrdup("selinux", GFP_KERNEL); + if (!*lsm_name) + return -ENOMEM; + + new_state = kzalloc(strlen(security_state_string) + 1, GFP_KERNEL); + if (!new_state) { + kfree(*lsm_name); + *lsm_name = NULL; + rc = -ENOMEM; + goto out; + } + + *state_len = sprintf(new_state, security_state_string, + !selinux_disabled(&selinux_state), + enforcing_enabled(&selinux_state)); + *state = new_state; + +out: + return rc; +} + +void notify_security_state_change(void) +{ + char *lsm_name = NULL; + void *state = NULL; + int state_len = 0; + + if (!selinux_security_state(&lsm_name, &state, &state_len)) { + security_state_change(lsm_name, state, state_len); + kfree(state); + kfree(lsm_name); + } +} + static void delayed_superblock_init(struct super_block *sb, void *unused) { selinux_set_mnt_opts(sb, NULL, 0, NULL); @@ -7247,6 +7288,7 @@ DEFINE_LSM(selinux) = { .enabled = &selinux_enabled_boot, .blobs = &selinux_blob_sizes, .init = selinux_init, + .security_state = selinux_security_state, }; #if defined(CONFIG_NETFILTER) @@ -7357,6 +7399,7 @@ int selinux_disable(struct selinux_state *state) } selinux_mark_disabled(state); + notify_security_state_change(); pr_info("SELinux: Disabled at runtime.\n"); diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index b0e02cfe3ce1..83c6ada45c7c 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -232,6 +232,8 @@ size_t security_policydb_len(struct selinux_state *state); int security_policycap_supported(struct selinux_state *state, unsigned int req_cap); +void notify_security_state_change(void); + #define SEL_VEC_MAX 32 struct av_decision { u32 allowed; diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 4781314c2510..8a5ba32a7775 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -173,6 +173,7 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf, from_kuid(&init_user_ns, audit_get_loginuid(current)), audit_get_sessionid(current)); enforcing_set(state, new_value); + notify_security_state_change(); if (new_value) avc_ss_reset(state->avc, 0); selnl_notify_setenforce(new_value);