audit: refactor audit_receive_msg() to clarify AUDIT_*_RULE* cases

audit_receive_msg() needlessly contained a fallthrough case that called
audit_receive_filter(), containing no common code between the cases.  Separate
them to make the logic clearer.  Refactor AUDIT_LIST_RULES, AUDIT_ADD_RULE,
AUDIT_DEL_RULE cases to create audit_rule_change(), audit_list_rules_send()
functions.  This should not functionally change the logic.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

2 files changed, 45 insertions, 33 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index fdb8528ceca3..c460f33c2801 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -903,11 +903,12 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                         audit_log_end(ab);
                         return -EPERM;
                 }
-                /* fallthrough */
-        case AUDIT_LIST_RULES:
-                err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid,
+                err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
                                            seq, data, nlmsg_len(nlh));
                 break;
+        case AUDIT_LIST_RULES:
+                err = audit_list_rules_send(NETLINK_CB(skb).portid, seq);
+                break;
         case AUDIT_TRIM:
                 audit_trim_trees();
                 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index d085cfbe416e..6cc8240b7aaf 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1023,47 +1023,20 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 }
 
 /**
- * audit_receive_filter - apply all rules to the specified message type
+ * 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_receive_filter(int type, __u32 portid, int seq, void *data,
-                         size_t datasz)
+int audit_rule_change(int type, __u32 portid, int seq, void *data,
+                        size_t datasz)
 {
-        struct task_struct *tsk;
-        struct audit_netlink_list *dest;
         int err = 0;
         struct audit_entry *entry;
 
         switch (type) {
-        case AUDIT_LIST_RULES:
-                /* We can't just spew out the rules here because we might fill
-                 * the available socket buffer space and deadlock waiting for
-                 * auditctl to read from it... which isn't ever going to
-                 * happen if we're actually running in the context of auditctl
-                 * trying to _send_ the stuff */
-
-                dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
-                if (!dest)
-                        return -ENOMEM;
-                dest->portid = portid;
-                dest->pid = task_pid_vnr(current);
-                skb_queue_head_init(&dest->q);
-
-                mutex_lock(&audit_filter_mutex);
-                audit_list_rules(portid, seq, &dest->q);
-                mutex_unlock(&audit_filter_mutex);
-
-                tsk = kthread_run(audit_send_list, dest, "audit_send_list");
-                if (IS_ERR(tsk)) {
-                        skb_queue_purge(&dest->q);
-                        kfree(dest);
-                        err = PTR_ERR(tsk);
-                }
-                break;
         case AUDIT_ADD_RULE:
                 entry = audit_data_to_entry(data, datasz);
                 if (IS_ERR(entry))
@@ -1090,6 +1063,44 @@ int audit_receive_filter(int type, __u32 portid, int seq, void *data,
         return err;
 }
 
+/**
+ * audit_list_rules_send - list the audit rules
+ * @portid: target portid for netlink audit messages
+ * @seq: netlink audit message sequence (serial) number
+ */
+int audit_list_rules_send(__u32 portid, int seq)
+{
+        struct task_struct *tsk;
+        struct audit_netlink_list *dest;
+        int err = 0;
+
+        /* We can't just spew out the rules here because we might fill
+         * the available socket buffer space and deadlock waiting for
+         * auditctl to read from it... which isn't ever going to
+         * happen if we're actually running in the context of auditctl
+         * trying to _send_ the stuff */
+
+        dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
+        if (!dest)
+                return -ENOMEM;
+        dest->portid = portid;
+        dest->pid = task_pid_vnr(current);
+        skb_queue_head_init(&dest->q);
+
+        mutex_lock(&audit_filter_mutex);
+        audit_list_rules(portid, seq, &dest->q);
+        mutex_unlock(&audit_filter_mutex);
+
+        tsk = kthread_run(audit_send_list, dest, "audit_send_list");
+        if (IS_ERR(tsk)) {
+                skb_queue_purge(&dest->q);
+                kfree(dest);
+                err = PTR_ERR(tsk);
+        }
+
+        return err;
+}
+
 int audit_comparator(u32 left, u32 op, u32 right)
 {
         switch (op) {