[PATCH] audit signal recipients

When auditing syscalls that send signals, log the pid and security
context for each target process. Optimize the data collection by
adding a counter for signal-related rules, and avoiding allocating an
aux struct unless we have more than one target process. For process
groups, collect pid/context data in blocks of 16. Move the
audit_signal_info() hook up in check_kill_permission() so we audit
attempts where permission is denied.

Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/audit.h b/kernel/audit.h
index a337023..815d6f5 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -83,6 +83,7 @@
 	u32			field_count;
 	char			*filterkey; /* ties events to rules */
 	struct audit_field	*fields;
+	struct audit_field	*arch_f; /* quick access to arch field */
 	struct audit_field	*inode_f; /* quick access to an inode field */
 	struct audit_watch	*watch;	/* associated watch */
 	struct list_head	rlist;	/* entry in audit_watch.rules list */
@@ -131,17 +132,19 @@
 extern int selinux_audit_rule_update(void);
 
 #ifdef CONFIG_AUDITSYSCALL
-extern void __audit_signal_info(int sig, struct task_struct *t);
-static inline void audit_signal_info(int sig, struct task_struct *t)
+extern int __audit_signal_info(int sig, struct task_struct *t);
+static inline int audit_signal_info(int sig, struct task_struct *t)
 {
-	if (unlikely(audit_pid && t->tgid == audit_pid))
-		__audit_signal_info(sig, t);
+	if (unlikely((audit_pid && t->tgid == audit_pid) ||
+		     (audit_signals && !audit_dummy_context())))
+		return __audit_signal_info(sig, t);
+	return 0;
 }
 extern enum audit_state audit_filter_inodes(struct task_struct *,
 					    struct audit_context *);
 extern void audit_set_auditable(struct audit_context *);
 #else
-#define audit_signal_info(s,t)
+#define audit_signal_info(s,t) AUDIT_DISABLED
 #define audit_filter_inodes(t,c) AUDIT_DISABLED
 #define audit_set_auditable(c)
 #endif