From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757310Ab1I3Jqc (ORCPT ); Fri, 30 Sep 2011 05:46:32 -0400 Received: from mga10.intel.com ([192.55.52.92]:3225 "EHLO fmsmga102.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753940Ab1I3Jqa (ORCPT ); Fri, 30 Sep 2011 05:46:30 -0400 From: Jarkko Sakkinen To: Casey Schaufler Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Jarkko Sakkinen Subject: [PATCH] Smack: domain transition protections (v2) Date: Fri, 30 Sep 2011 12:46:15 +0300 Message-Id: <1317375975-13427-1-git-send-email-jarkko.sakkinen@intel.com> X-Mailer: git-send-email 1.7.4.1 Organization: Intel Finland Oy - BIC 0357606-4 - PL 281, 00181 Helsinki Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Protections for domain transition: - BPRM unsafe flags - Secureexec - Clear unsafe personality bits. - Clear parent death signal Signed-off-by: Jarkko Sakkinen --- security/smack/smack.h | 2 + security/smack/smack_lsm.c | 62 ++++++++++++++++++++++++++++++++++++-------- 2 files changed, 53 insertions(+), 11 deletions(-) diff --git a/security/smack/smack.h b/security/smack/smack.h index 174d3be..d377099 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -60,12 +60,14 @@ struct inode_smack { struct task_smack { char *smk_task; /* label for access control */ char *smk_forked; /* label when forked */ + int smk_flags; /* smack task flags */ struct list_head smk_rules; /* per task access rules */ struct mutex smk_rules_lock; /* lock for the rules */ }; #define SMK_INODE_INSTANT 0x01 /* inode is instantiated */ #define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */ +#define SMK_TASK_TRANSITION 0x01 /* task needs secureexec mode */ /* * A label access rule. diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 2e71c3f..78e0056 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -5,12 +5,13 @@ * * Authors: * Casey Schaufler - * Jarkko Sakkinen + * Jarkko Sakkinen * * Copyright (C) 2007 Casey Schaufler * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. * Paul Moore * Copyright (C) 2010 Nokia Corporation + * Copyright (C) 2011 Intel Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, @@ -441,11 +442,17 @@ static int smack_sb_umount(struct vfsmount *mnt, int flags) * BPRM hooks */ +/** + * smack_bprm_set_creds - Smack exec that handles the domain transfer. + * @bprm: binprm for exec + * + * Returns 0 on success. + */ static int smack_bprm_set_creds(struct linux_binprm *bprm) { - struct task_smack *tsp = bprm->cred->security; + struct inode *inode = bprm->file->f_path.dentry->d_inode; + struct task_smack *bsp = bprm->cred->security; struct inode_smack *isp; - struct dentry *dp; int rc; rc = cap_bprm_set_creds(bprm); @@ -455,20 +462,51 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (bprm->cred_prepared) return 0; - if (bprm->file == NULL || bprm->file->f_dentry == NULL) + isp = inode->i_security; + if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; - dp = bprm->file->f_dentry; + if (bprm->unsafe) + return -EPERM; - if (dp->d_inode == NULL) - return 0; + bsp->smk_task = isp->smk_task; + bsp->smk_flags = SMK_TASK_TRANSITION; + bprm->per_clear |= PER_CLEAR_ON_SETID; - isp = dp->d_inode->i_security; + return 0; +} + +/** + * smack_bprm_committing_creds - Prepare to install the new credentials + * from bprm. + * + * @bprm: binprm for exec + */ +static void smack_bprm_committing_creds(struct linux_binprm *bprm) +{ + struct task_smack *bsp = bprm->cred->security; - if (isp->smk_task != NULL) - tsp->smk_task = isp->smk_task; + if (!(bsp->smk_flags & SMK_TASK_TRANSITION)) + return; - return 0; + current->pdeath_signal = 0; +} + +/** + * smack_bprm_secureexec - Return the decision to use secureexec. + * @bprm: binprm for exec + * + * Returns 0 on success. + */ +static int smack_bprm_secureexec(struct linux_binprm *bprm) +{ + struct task_smack *tsp = current_security(); + int ret = cap_bprm_secureexec(bprm); + + if (!ret && (tsp->smk_flags & SMK_TASK_TRANSITION)) + ret = 1; + + return ret; } /* @@ -3452,6 +3490,8 @@ struct security_operations smack_ops = { .sb_umount = smack_sb_umount, .bprm_set_creds = smack_bprm_set_creds, + .bprm_committing_creds = smack_bprm_committing_creds, + .bprm_secureexec = smack_bprm_secureexec, .inode_alloc_security = smack_inode_alloc_security, .inode_free_security = smack_inode_free_security, -- 1.7.4.1