[PATCH ghak90 V7 16/21] audit: add support for contid set/get by netlink

[Richard Guy Briggs <rgb@xxxxxxxxxx>]

Add the ability to get and set the audit container identifier using an
audit netlink message using message types AUDIT_SET_CONTID 1023 and
AUDIT_GET_CONTID 1022 in addition to using the proc filesystem.  The
message format includes the data structure:

struct audit_contid_status {
       pid_t   pid;
       u64     id;
};

Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
 include/uapi/linux/audit.h |  2 ++
 kernel/audit.c             | 40 ++++++++++++++++++++++++++++++++++++++++
 kernel/audit.h             |  5 +++++
 3 files changed, 47 insertions(+)

diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index f34108759e8f..e26729fc9943 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -73,6 +73,8 @@
 #define AUDIT_GET_FEATURE	1019	/* Get which features are enabled */
 #define AUDIT_CONTAINER_OP	1020	/* Define the container id and info */
 #define AUDIT_SIGNAL_INFO2	1021	/* Get info auditd signal sender */
+#define AUDIT_GET_CONTID	1022	/* Get contid of a task */
+#define AUDIT_SET_CONTID	1023	/* Set contid of a task */
 
 #define AUDIT_FIRST_USER_MSG	1100	/* Userspace messages mostly uninteresting to kernel */
 #define AUDIT_USER_AVC		1107	/* We filter this differently */
diff --git a/kernel/audit.c b/kernel/audit.c
index 4fe7678304dd..df92de20ed73 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1216,6 +1216,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 	case AUDIT_TTY_SET:
 	case AUDIT_TRIM:
 	case AUDIT_MAKE_EQUIV:
+	case AUDIT_GET_CONTID:
+	case AUDIT_SET_CONTID:
 		/* Only support auditd and auditctl in initial pid namespace
 		 * for now. */
 		if (task_active_pid_ns(current) != &init_pid_ns)
@@ -1273,6 +1275,23 @@ static int audit_get_feature(struct sk_buff *skb)
 	return 0;
 }
 
+static int audit_get_contid_status(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+	u32 seq = nlh->nlmsg_seq;
+	void *data = nlmsg_data(nlh);
+	struct audit_contid_status cs;
+
+	cs.pid = ((struct audit_contid_status *)data)->pid;
+	if (!cs.pid)
+		cs.pid = task_tgid_nr(current);
+	rcu_read_lock();
+	cs.id = audit_get_contid(find_task_by_vpid(cs.pid));
+	rcu_read_unlock();
+	audit_send_reply(skb, seq, AUDIT_GET_CONTID, 0, 0, &cs, sizeof(cs));
+	return 0;
+}
+
 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
 				     u32 old_lock, u32 new_lock, int res)
 {
@@ -1700,6 +1719,27 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		audit_log_end(ab);
 		break;
 	}
+	case AUDIT_SET_CONTID: {
+		struct audit_contid_status *s = data;
+		struct task_struct *tsk;
+
+		/* check if new data is valid */
+		if (nlmsg_len(nlh) < sizeof(*s))
+			return -EINVAL;
+		tsk = find_get_task_by_vpid(s->pid);
+		if (!tsk)
+			return -EINVAL;
+
+		err = audit_set_contid(tsk, s->id);
+		put_task_struct(tsk);
+		return err;
+		break;
+	}
+	case AUDIT_GET_CONTID:
+		err = audit_get_contid_status(skb);
+		if (err)
+			return err;
+		break;
 	default:
 		err = -EINVAL;
 		break;
diff --git a/kernel/audit.h b/kernel/audit.h
index c9b73abfd6a0..25732fbc47a4 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -224,6 +224,11 @@ static inline int audit_hash_contid(u64 contid)
 
 #define AUDIT_CONTID_COUNT	1 << 16
 
+struct audit_contid_status {
+	pid_t	pid;
+	u64	id;
+};
+
 /* Indicates that audit should log the full pathname. */
 #define AUDIT_NAME_FULL -1
 
-- 
1.8.3.1