mm, security: Add lsm hook for set_mempolicy_home_node(2)

In container environment, we don't want users to bind their memory to a
specific numa node, while we want to unit control memory resource with
kubelet. Therefore, add a new lsm hook for set_mempolicy_home_node(2), then
we can enforce fine-grained control over memory policy adjustment by the
tasks in a container.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>

include/linux/lsm_hook_defs.h

@@ -425,3 +425,5 @@ LSM_HOOK(int, 0, mbind, unsigned long start, unsigned long len,
 	 unsigned long maxnode, unsigned int flags)
 LSM_HOOK(int, 0, set_mempolicy, int mode, const unsigned long __user *nmask,
 	 unsigned long maxnode)
+LSM_HOOK(int, 0, set_mempolicy_home_node, unsigned long start, unsigned long len,
+	 unsigned long home_node, unsigned long flags)

include/linux/security.h

@@ -489,6 +489,8 @@ int security_mbind(unsigned long start, unsigned long len,
 		   unsigned long maxnode, unsigned int flags);
 int security_set_mempolicy(int mode, const unsigned long __user *nmask,
 			   unsigned long maxnode);
+int security_set_mempolicy_home_node(unsigned long start, unsigned long len,
+				     unsigned long home_node, unsigned long flags);
 #else /* CONFIG_SECURITY */
 
 static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
@@ -1413,6 +1415,12 @@ static inline int security_set_mempolicy(int mode, const unsigned long __user *n
 {
 	return 0;
 }
+
+static inline int security_set_mempolicy_home_node(unsigned long start, unsigned long len,
+						   unsigned long home_node, unsigned long flags)
+{
+	return 0;
+}
 #endif	/* CONFIG_SECURITY */
 
 #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)

mm/mempolicy.c

@@ -1523,6 +1523,11 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
 		return -EINVAL;
 	if (end == start)
 		return 0;
+
+	err = security_set_mempolicy_home_node(start, len, home_node, flags);
+	if (err)
+		return err;
+
 	mmap_write_lock(mm);
 	prev = vma_prev(&vmi);
 	for_each_vma_range(vmi, vma, end) {

security/security.c

@@ -5349,3 +5349,10 @@ int security_set_mempolicy(int mode, const unsigned long __user *nmask, unsigned
 {
 	return call_int_hook(set_mempolicy, 0, mode, nmask, maxnode);
 }
+
+int security_set_mempolicy_home_node(unsigned long start, unsigned long len,
+				     unsigned long home_node, unsigned long flags)
+{
+
+	return call_int_hook(set_mempolicy_home_node, 0, start, len, home_node, flags);
+}