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Subject[PATCH] Smack: domain transition protections (v3)
Date
Protections for domain transition:

- BPRM unsafe flags
- Secureexec
- Clear unsafe personality bits.
- Clear parent death signal

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
---
security/smack/smack_lsm.c | 59 +++++++++++++++++++++++++++++++++++--------
1 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 2e71c3f..f1ef41c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -5,12 +5,13 @@
*
* Authors:
* Casey Schaufler <casey@schaufler-ca.com>
- * Jarkko Sakkinen <ext-jarkko.2.sakkinen@nokia.com>
+ * Jarkko Sakkinen <jarkko.sakkinen@intel.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
* 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 +462,48 @@ 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;
+
+ bsp->smk_task = isp->smk_task;
+ bprm->per_clear |= PER_CLEAR_ON_SETID;

- if (dp->d_inode == NULL)
- return 0;
+ return 0;
+}

- isp = dp->d_inode->i_security;
+/**
+ * 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_task != bsp->smk_forked)
+ current->pdeath_signal = 0;
+}

- return 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_task != tsp->smk_forked))
+ ret = 1;
+
+ return ret;
}

/*
@@ -3452,6 +3487,8 @@ 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


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