[PATCH 1/2] audit: log binding and unbinding to netlink multicast socket

[Steve Grubb <sgrubb@redhat.com>]

The audit subsystem could use a function that logs the commonly needed
fields for a typical audit event. This logs less that audit_log_task_info
and reduces the need to hand code individual fields.

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
---
 include/linux/audit.h |  5 +++++
 kernel/audit.c        | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index c2e7e3a..2620847 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -484,6 +484,8 @@ static inline void	    audit_log_secctx(struct audit_buffer *ab, u32 secid)
 extern int audit_log_task_context(struct audit_buffer *ab);
 extern void audit_log_task_info(struct audit_buffer *ab,
 				struct task_struct *tsk);
+extern void audit_log_task_simple(struct audit_buffer *ab,
+				struct task_struct *tsk);
 
 extern int		    audit_update_lsm_rules(void);
 
@@ -540,6 +542,9 @@ static inline int audit_log_task_context(struct audit_buffer *ab)
 static inline void audit_log_task_info(struct audit_buffer *ab,
 				       struct task_struct *tsk)
 { }
+static inline void audit_log_task_simple(struct audit_buffer *ab,
+				       struct task_struct *tsk)
+{ }
 #define audit_enabled 0
 #endif /* CONFIG_AUDIT */
 static inline void audit_log_string(struct audit_buffer *ab, const char *buf)
diff --git a/kernel/audit.c b/kernel/audit.c
index 1c13e42..29fb38b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1100,6 +1100,41 @@ static void audit_receive(struct sk_buff  *skb)
 	mutex_unlock(&audit_cmd_mutex);
 }
 
+/* This function logs the essential information needed to understand
+ * what or who is causing the event */
+void audit_log_task_simple(struct audit_buffer *ab, struct task_struct *tsk)
+{
+	const struct cred *cred;
+	char comm[sizeof(tsk->comm)];
+	char *tty;
+
+	if (!ab)
+		return;
+
+	/* tsk == current */
+	cred = current_cred();
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
+		tty = tsk->signal->tty->name;
+	else
+		tty = "(none)";
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
+			 task_pid_nr(tsk),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
+			 tty, audit_get_sessionid(tsk));
+
+	audit_log_task_context(ab); /* subj= */
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
+
+	audit_log_d_path_exe(ab, tsk->mm); /* exe= */
+}
+EXPORT_SYMBOL(audit_log_task_simple);
+
 /* Run custom bind function on netlink socket group connect or bind requests. */
 static int audit_bind(struct net *net, int group)
 {
-- 
2.4.3