security: allow Yama to be unconditionally stacked
Unconditionally call Yama when CONFIG_SECURITY_YAMA_STACKED is selected,
no matter what LSM module is primary.
Ubuntu and Chrome OS already carry patches to do this, and Fedora
has voiced interest in doing this as well. Instead of having multiple
distributions (or LSM authors) carrying these patches, just allow Yama
to be called unconditionally when selected by the new CONFIG.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index d51b7c7..9ca43c1 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -100,7 +100,7 @@
* yama_task_free - check for task_pid to remove from exception list
* @task: task being removed
*/
-static void yama_task_free(struct task_struct *task)
+void yama_task_free(struct task_struct *task)
{
yama_ptracer_del(task, task);
}
@@ -116,7 +116,7 @@
* Return 0 on success, -ve on error. -ENOSYS is returned when Yama
* does not handle the given option.
*/
-static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
+int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
int rc;
@@ -243,7 +243,7 @@
*
* Returns 0 if following the ptrace is allowed, -ve on error.
*/
-static int yama_ptrace_access_check(struct task_struct *child,
+int yama_ptrace_access_check(struct task_struct *child,
unsigned int mode)
{
int rc;
@@ -296,7 +296,7 @@
*
* Returns 0 if following the ptrace is allowed, -ve on error.
*/
-static int yama_ptrace_traceme(struct task_struct *parent)
+int yama_ptrace_traceme(struct task_struct *parent)
{
int rc;
@@ -330,6 +330,7 @@
return rc;
}
+#ifndef CONFIG_SECURITY_YAMA_STACKED
static struct security_operations yama_ops = {
.name = "yama",
@@ -338,6 +339,7 @@
.task_prctl = yama_task_prctl,
.task_free = yama_task_free,
};
+#endif
#ifdef CONFIG_SYSCTL
static int yama_dointvec_minmax(struct ctl_table *table, int write,
@@ -384,13 +386,17 @@
static __init int yama_init(void)
{
+#ifndef CONFIG_SECURITY_YAMA_STACKED
if (!security_module_enable(&yama_ops))
return 0;
+#endif
printk(KERN_INFO "Yama: becoming mindful.\n");
+#ifndef CONFIG_SECURITY_YAMA_STACKED
if (register_security(&yama_ops))
panic("Yama: kernel registration failed.\n");
+#endif
#ifdef CONFIG_SYSCTL
if (!register_sysctl_paths(yama_sysctl_path, yama_sysctl_table))
