[RFC PATCH 2/4] audit: kernel generated netlink traffic should have a portid of 0

[Paul Moore <pmoore@redhat.com>]

From: Paul Moore <paul@paul-moore.com>

We were setting the portid incorrectly in the netlink message headers,
fix that to always be 0 (nlmsg_pid = 0).

Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 include/linux/audit.h |    3 +--
 kernel/audit.c        |   23 ++++++-----------------
 kernel/audit.h        |    3 +--
 kernel/auditfilter.c  |   14 ++++++--------
 4 files changed, 14 insertions(+), 29 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 504e784b7ffa..cc0497c39472 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -163,8 +163,7 @@ extern void audit_log_task_info(struct audit_buffer *ab,
 extern int		    audit_update_lsm_rules(void);
 
 				/* Private API (for audit.c only) */
-extern int audit_rule_change(int type, __u32 portid, int seq,
-				void *data, size_t datasz);
+extern int audit_rule_change(int type, int seq, void *data, size_t datasz);
 extern int audit_list_rules_send(struct sk_buff *request_skb, int seq);
 
 extern u32 audit_enabled;
diff --git a/kernel/audit.c b/kernel/audit.c
index 4037869b4b64..6cbf47a372e8 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -251,14 +251,6 @@ static struct sock *audit_get_sk(const struct net *net)
 	return aunet->sk;
 }
 
-static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
-{
-	if (ab) {
-		struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
-		nlh->nlmsg_pid = portid;
-	}
-}
-
 void audit_panic(const char *message)
 {
 	switch (audit_failure) {
@@ -819,7 +811,7 @@ int audit_send_list(void *_dest)
 	return 0;
 }
 
-struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
+struct sk_buff *audit_make_reply(int seq, int type, int done,
 				 int multi, const void *payload, int size)
 {
 	struct sk_buff	*skb;
@@ -832,7 +824,7 @@ struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
 	if (!skb)
 		return NULL;
 
-	nlh	= nlmsg_put(skb, portid, seq, t, size, flags);
+	nlh	= nlmsg_put(skb, 0, seq, t, size, flags);
 	if (!nlh)
 		goto out_kfree_skb;
 	data = nlmsg_data(nlh);
@@ -876,7 +868,6 @@ static int audit_send_reply_thread(void *arg)
 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
 			     int multi, const void *payload, int size)
 {
-	u32 portid = NETLINK_CB(request_skb).portid;
 	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
 	struct sk_buff *skb;
 	struct task_struct *tsk;
@@ -886,12 +877,12 @@ static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int
 	if (!reply)
 		return;
 
-	skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
+	skb = audit_make_reply(seq, type, done, multi, payload, size);
 	if (!skb)
 		goto out;
 
 	reply->net = get_net(net);
-	reply->portid = portid;
+	reply->portid = NETLINK_CB(request_skb).portid;
 	reply->skb = skb;
 
 	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
@@ -1075,7 +1066,7 @@ static int audit_replace(pid_t pid)
 {
 	struct sk_buff *skb;
 
-	skb = audit_make_reply(0, 0, AUDIT_REPLACE, 0, 0, &pid, sizeof(pid));
+	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pid, sizeof(pid));
 	if (!skb)
 		return -ENOMEM;
 	return auditd_send_unicast_skb(skb);
@@ -1245,7 +1236,6 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 					size--;
 				audit_log_n_untrustedstring(ab, data, size);
 			}
-			audit_set_portid(ab, NETLINK_CB(skb).portid);
 			audit_log_end(ab);
 		}
 		break;
@@ -1259,8 +1249,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			audit_log_end(ab);
 			return -EPERM;
 		}
-		err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
-					   seq, data, nlmsg_len(nlh));
+		err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
 		break;
 	case AUDIT_LIST_RULES:
 		err = audit_list_rules_send(skb, seq);
diff --git a/kernel/audit.h b/kernel/audit.h
index 0f1cf6d1878a..c21b74dd7ff2 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -237,8 +237,7 @@ extern int audit_uid_comparator(kuid_t left, u32 op, kuid_t right);
 extern int audit_gid_comparator(kgid_t left, u32 op, kgid_t right);
 extern int parent_len(const char *path);
 extern int audit_compare_dname_path(const char *dname, const char *path, int plen);
-extern struct sk_buff *audit_make_reply(__u32 portid, int seq, int type,
-					int done, int multi,
+extern struct sk_buff *audit_make_reply(int seq, int type, int done, int multi,
 					const void *payload, int size);
 extern void		    audit_panic(const char *message);
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 880519d6cf2a..81cdf8d8f319 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1033,7 +1033,7 @@ int audit_del_rule(struct audit_entry *entry)
 }
 
 /* List rules using struct audit_rule_data. */
-static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
+static void audit_list_rules(int seq, struct sk_buff_head *q)
 {
 	struct sk_buff *skb;
 	struct audit_krule *r;
@@ -1048,15 +1048,15 @@ static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
 			data = audit_krule_to_data(r);
 			if (unlikely(!data))
 				break;
-			skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
-					       0, 1, data,
+			skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
+					       data,
 					       sizeof(*data) + data->buflen);
 			if (skb)
 				skb_queue_tail(q, skb);
 			kfree(data);
 		}
 	}
-	skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
+	skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
 	if (skb)
 		skb_queue_tail(q, skb);
 }
@@ -1085,13 +1085,11 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 /**
  * audit_rule_change - apply all rules to the specified message type
  * @type: audit message type
- * @portid: target port id for netlink audit messages
  * @seq: netlink audit message sequence (serial) number
  * @data: payload data
  * @datasz: size of payload data
  */
-int audit_rule_change(int type, __u32 portid, int seq, void *data,
-			size_t datasz)
+int audit_rule_change(int type, int seq, void *data, size_t datasz)
 {
 	int err = 0;
 	struct audit_entry *entry;
@@ -1150,7 +1148,7 @@ int audit_list_rules_send(struct sk_buff *request_skb, int seq)
 	skb_queue_head_init(&dest->q);
 
 	mutex_lock(&audit_filter_mutex);
-	audit_list_rules(portid, seq, &dest->q);
+	audit_list_rules(seq, &dest->q);
 	mutex_unlock(&audit_filter_mutex);
 
 	tsk = kthread_run(audit_send_list, dest, "audit_send_list");