[PATCH 16/20] audit: allow GET, SET, USER MSG operations in audit namespace

[Gao feng]

1, remove the permission check of pid namespace. it's no reason
   to deny un-init pid namespace to operate audit subsystem.

2, only allow init user namespace and init audit namespace to
   operate list/add/del rule, tty set, trim, make equiv operations.

3, allow audit namespace to get/set audit configuration, send
   userspace audit message.

Signed-off-by: Gao feng <gaofeng at cn.fujitsu.com>
---
 kernel/audit.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 095f54d..c4d4291 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -573,11 +573,7 @@ out:
 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 {
 	int err = 0;
-
-	/* Only support the initial namespaces for now. */
-	if ((current_user_ns() != &init_user_ns) ||
-	    (task_active_pid_ns(current) != &init_pid_ns))
-		return -EPERM;
+	struct audit_namespace *ns = current->nsproxy->audit_ns;
 
 	switch (msg_type) {
 	case AUDIT_LIST:
@@ -586,6 +582,7 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 		return -EOPNOTSUPP;
 	case AUDIT_GET:
 	case AUDIT_SET:
+		break;
 	case AUDIT_LIST_RULES:
 	case AUDIT_ADD_RULE:
 	case AUDIT_DEL_RULE:
@@ -594,13 +591,15 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 	case AUDIT_TTY_SET:
 	case AUDIT_TRIM:
 	case AUDIT_MAKE_EQUIV:
-		if (!capable(CAP_AUDIT_CONTROL))
+		if ((current_user_ns() != &init_user_ns) ||
+		    (ns != &init_audit_ns) ||
+		    !capable(CAP_AUDIT_CONTROL))
 			err = -EPERM;
 		break;
 	case AUDIT_USER:
 	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
-		if (!capable(CAP_AUDIT_WRITE))
+		if (!ns_capable(ns->user_ns, CAP_AUDIT_WRITE))
 			err = -EPERM;
 		break;
 	default:  /* bad msg */
-- 
1.8.3.1