[PATCH] support for context based audit filtering, part 2

This patch provides the ability to filter audit messages based on the
elements of the process' SELinux context (user, role, type, mls sensitivity,
and mls clearance).  It uses the new interfaces from selinux to opaquely
store information related to the selinux context and to filter based on that
information.  It also uses the callback mechanism provided by selinux to
refresh the information when a new policy is loaded.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8aca4ab..d3d97d2 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -58,6 +58,7 @@
 #include <linux/security.h>
 #include <linux/list.h>
 #include <linux/tty.h>
+#include <linux/selinux.h>
 
 #include "audit.h"
 
@@ -168,6 +169,9 @@
 			      enum audit_state *state)
 {
 	int i, j;
+	u32 sid;
+
+	selinux_task_ctxid(tsk, &sid);
 
 	for (i = 0; i < rule->field_count; i++) {
 		struct audit_field *f = &rule->fields[i];
@@ -257,6 +261,22 @@
 			if (ctx)
 				result = audit_comparator(ctx->loginuid, f->op, f->val);
 			break;
+		case AUDIT_SE_USER:
+		case AUDIT_SE_ROLE:
+		case AUDIT_SE_TYPE:
+		case AUDIT_SE_SEN:
+		case AUDIT_SE_CLR:
+			/* NOTE: this may return negative values indicating
+			   a temporary error.  We simply treat this as a
+			   match for now to avoid losing information that
+			   may be wanted.   An error message will also be
+			   logged upon error */
+			if (f->se_rule)
+				result = selinux_audit_rule_match(sid, f->type,
+				                                  f->op,
+				                                  f->se_rule,
+				                                  ctx);
+			break;
 		case AUDIT_ARG0:
 		case AUDIT_ARG1:
 		case AUDIT_ARG2: