[PATCH v12 8/9] LSM: Multiple concurrent LSMs

Casey Schaufler
2013-01-08T02:09:31Z

Subject: [PATCH v12 8/9] LSM: Multiple concurrent LSMs

Change the infrastructure for Linux Security Modules (LSM)s
from a single vector of hook handlers to a list based method
for handling multiple concurrent modules.

Abstract access to security blobs.
Remove commoncap calls.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

---
security/tomoyo/common.h | 6 +++--
security/tomoyo/domain.c | 2 +-
security/tomoyo/securityfs_if.c | 9 +++++---
security/tomoyo/tomoyo.c | 47 ++++++++++++++++++++++-----------------
4 files changed, 38 insertions(+), 26 deletions(-)

diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index d4f166b..ef0cdcc 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -28,6 +28,7 @@
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/un.h>
+#include <linux/lsm.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/ip.h>
@@ -1079,6 +1080,7 @@ extern struct list_head tomoyo_domain_list;
extern struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
extern struct list_head tomoyo_namespace_list;
extern struct mutex tomoyo_policy_lock;
+extern struct security_operations tomoyo_security_ops;
extern struct srcu_struct tomoyo_ss;
extern struct tomoyo_domain_info tomoyo_kernel_domain;
extern struct tomoyo_policy_namespace tomoyo_kernel_namespace;
@@ -1202,7 +1204,7 @@ static inline void tomoyo_put_group(struct tomoyo_group *group)
*/
static inline struct tomoyo_domain_info *tomoyo_domain(void)
{
- return current_cred()->security;
+ return lsm_get_cred(current_cred(), &tomoyo_security_ops);
}

/**
@@ -1215,7 +1217,7 @@ static inline struct tomoyo_domain_info *tomoyo_domain(void)
static inline struct tomoyo_domain_info *tomoyo_real_domain(struct task_struct
*task)
{
- return task_cred_xxx(task, security);
+ return lsm_get_cred(__task_cred(task), &tomoyo_security_ops);
}

/**
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 3865145..15042e7 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -840,7 +840,7 @@ force_jump_domain:
domain = old_domain;
/* Update reference count on "struct tomoyo_domain_info". */
atomic_inc(&domain->users);
- bprm->cred->security = domain;
+ lsm_set_cred(bprm->cred, domain, &tomoyo_security_ops);
kfree(exename.name);
if (!retval) {
ee->r.domain = domain;
diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c
index 8592f2fc..37feaf5 100644
--- a/security/tomoyo/securityfs_if.c
+++ b/security/tomoyo/securityfs_if.c
@@ -75,8 +75,10 @@ static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
error = -ENOMEM;
} else {
struct tomoyo_domain_info *old_domain =
- cred->security;
- cred->security = new_domain;
+ lsm_get_cred(cred,
+ &tomoyo_security_ops);
+ lsm_set_cred(cred, new_domain,
+ &tomoyo_security_ops);
atomic_inc(&new_domain->users);
atomic_dec(&old_domain->users);
commit_creds(cred);
@@ -242,7 +244,8 @@ static int __init tomoyo_initerface_init(void)
struct dentry *tomoyo_dir;

/* Don't create securityfs entries unless registered. */
- if (current_cred()->security != &tomoyo_kernel_domain)
+ if (lsm_get_cred(current_cred(), &tomoyo_security_ops) !=
+ &tomoyo_kernel_domain)
return 0;

tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index a2ee362..b2a58ae 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -17,7 +17,7 @@
*/
static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
{
- new->security = NULL;
+ lsm_set_cred(new, NULL, &tomoyo_security_ops);
return 0;
}

@@ -33,8 +33,10 @@ static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
gfp_t gfp)
{
- struct tomoyo_domain_info *domain = old->security;
- new->security = domain;
+ struct tomoyo_domain_info *domain;
+
+ domain = lsm_get_cred(old, &tomoyo_security_ops);
+ lsm_set_cred(new, domain, &tomoyo_security_ops);
if (domain)
atomic_inc(&domain->users);
return 0;
@@ -58,9 +60,13 @@ static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
*/
static void tomoyo_cred_free(struct cred *cred)
{
- struct tomoyo_domain_info *domain = cred->security;
- if (domain)
+ struct tomoyo_domain_info *domain;
+
+ domain = lsm_get_cred(cred, &tomoyo_security_ops);
+ if (domain) {
atomic_dec(&domain->users);
+ lsm_set_cred(cred, NULL, &tomoyo_security_ops);
+ }
}

/**
@@ -72,12 +78,6 @@ static void tomoyo_cred_free(struct cred *cred)
*/
static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
- int rc;
-
- rc = cap_bprm_set_creds(bprm);
- if (rc)
- return rc;
-
/*
* Do only if this function is called for the first time of an execve
* operation.
@@ -98,13 +98,13 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
* stored inside "bprm->cred->security" will be acquired later inside
* tomoyo_find_next_domain().
*/
- atomic_dec(&((struct tomoyo_domain_info *)
- bprm->cred->security)->users);
+ atomic_dec(&((struct tomoyo_domain_info *)lsm_get_cred(bprm->cred,
+ &tomoyo_security_ops))->users);
/*
* Tell tomoyo_bprm_check_security() is called for the first time of an
* execve operation.
*/
- bprm->cred->security = NULL;
+ lsm_set_cred(bprm->cred, NULL, &tomoyo_security_ops);
return 0;
}

@@ -117,8 +117,9 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
*/
static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
- struct tomoyo_domain_info *domain = bprm->cred->security;
+ struct tomoyo_domain_info *domain;

+ domain = lsm_get_cred(bprm->cred, &tomoyo_security_ops);
/*
* Execute permission is checked against pathname passed to do_execve()
* using current domain.
@@ -503,7 +504,7 @@ static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
* tomoyo_security_ops is a "struct security_operations" which is used for
* registering TOMOYO.
*/
-static struct security_operations tomoyo_security_ops = {
+struct security_operations tomoyo_security_ops = {
.name = "tomoyo",
.cred_alloc_blank = tomoyo_cred_alloc_blank,
.cred_prepare = tomoyo_cred_prepare,
@@ -545,16 +546,22 @@ struct srcu_struct tomoyo_ss;
*/
static int __init tomoyo_init(void)
{
+ int rc;
struct cred *cred = (struct cred *) current_cred();

+ /* register ourselves with the security framework */
if (!security_module_enable(&tomoyo_security_ops))
return 0;
- /* register ourselves with the security framework */
- if (register_security(&tomoyo_security_ops) ||
- init_srcu_struct(&tomoyo_ss))
+
+ if (init_srcu_struct(&tomoyo_ss))
panic("Failure registering TOMOYO Linux");
printk(KERN_INFO "TOMOYO Linux initialized\n");
- cred->security = &tomoyo_kernel_domain;
+
+ rc = lsm_set_init_cred(cred, &tomoyo_kernel_domain,
+ &tomoyo_security_ops);
+ if (rc)
+ panic("Failure allocating credential for TOMOYO Linux");
+
tomoyo_mm_init();
return 0;
}