[PATCH 2/2] audit: log failed attempts to change audit_pid configuration

[Richard Guy Briggs]

Failed attempts to change the audit_pid configuration are not presently
logged.  One case is an attempt to starve an old auditd by starting up a
new auditd when the old one is still alive and active.  The other case
is an attempt to orphan a new auditd when an old auditd shuts down.

Log both as AUDIT_CONFIG_CHANGE messages with failure result.

Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
---
 kernel/audit.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 3399ab2..65dcd45 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -883,12 +883,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			pid_t requesting_pid = task_tgid_vnr(current);
 			u32 portid = NETLINK_CB(skb).portid;
 
-			if ((!new_pid) && (requesting_pid != audit_pid))
+			if ((!new_pid) && (requesting_pid != audit_pid)) {
+				audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
 				return -EACCES;
+			}
 			if (audit_pid && new_pid &&
 			    audit_ping(requesting_pid, nlmsg_hdr(skb)->nlmsg_seq, portid) !=
-			    -ECONNREFUSED)
+			    -ECONNREFUSED) {
+				audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
 				return -EEXIST;
+			}
 			if (audit_enabled != AUDIT_OFF)
 				audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
 			audit_pid = new_pid;
-- 
1.7.1