Introduce two related changes to the TrustedBSD MAC Framework:

(1) Abstract interpreter vnode labeling in execve(2) and mac_execve(2)
    so that the general exec code isn't aware of the details of
    allocating, copying, and freeing labels, rather, simply passes in
    a void pointer to start and stop functions that will be used by
    the framework.  This change will be MFC'd.

(2) Introduce a new flags field to the MAC_POLICY_SET(9) interface
    allowing policies to declare which types of objects require label
    allocation, initialization, and destruction, and define a set of
    flags covering various supported object types (MPC_OBJECT_PROC,
    MPC_OBJECT_VNODE, MPC_OBJECT_INPCB, ...).  This change reduces the
    overhead of compiling the MAC Framework into the kernel if policies
    aren't loaded, or if policies require labels on only a small number
    or even no object types.  Each time a policy is loaded or unloaded,
    we recalculate a mask of labeled object types across all policies
    present in the system.  Eliminate MAC_ALWAYS_LABEL_MBUF option as it
    is no longer required.

MFC after:	1 week ((1) only)
Reviewed by:	csjp
Obtained from:	TrustedBSD Project
Sponsored by:	Apple, Inc.

1 files changed, 17 insertions, 6 deletions

diff --git a/sys/security/mac/mac_sysv_msg.c b/sys/security/mac/mac_sysv_msg.c
index 5db6270..2c5bbca 100644
--- a/sys/security/mac/mac_sysv_msg.c
+++ b/sys/security/mac/mac_sysv_msg.c
@@ -1,6 +1,7 @@
 /*-
  * Copyright (c) 2003-2004 Networks Associates Technology, Inc.
  * Copyright (c) 2006 SPARTA, Inc.
+ * Copyright (c) 2008 Apple Inc.
  * All rights reserved.
  *
  * This software was developed for the FreeBSD Project in part by Network
@@ -70,7 +71,10 @@ void
 mac_sysvmsg_init(struct msg *msgptr)
 {
 
-	msgptr->label = mac_sysv_msgmsg_label_alloc();
+	if (mac_labeled & MPC_OBJECT_SYSVMSG)
+		msgptr->label = mac_sysv_msgmsg_label_alloc();
+	else
+		msgptr->label = NULL;
 }
 
 static struct label *
@@ -87,7 +91,10 @@ void
 mac_sysvmsq_init(struct msqid_kernel *msqkptr)
 {
 
-	msqkptr->label = mac_sysv_msgqueue_label_alloc();
+	if (mac_labeled & MPC_OBJECT_SYSVMSQ)
+		msqkptr->label = mac_sysv_msgqueue_label_alloc();
+	else
+		msqkptr->label = NULL;
 }
 
 static void
@@ -102,8 +109,10 @@ void
 mac_sysvmsg_destroy(struct msg *msgptr)
 {
 
-	mac_sysv_msgmsg_label_free(msgptr->label);
-	msgptr->label = NULL;
+	if (msgptr->label != NULL) {
+		mac_sysv_msgmsg_label_free(msgptr->label);
+		msgptr->label = NULL;
+	}
 }
 
 static void
@@ -118,8 +127,10 @@ void
 mac_sysvmsq_destroy(struct msqid_kernel *msqkptr)
 {
 
-	mac_sysv_msgqueue_label_free(msqkptr->label);
-	msqkptr->label = NULL;
+	if (msqkptr->label != NULL) {
+		mac_sysv_msgqueue_label_free(msqkptr->label);
+		msqkptr->label = NULL;
+	}
 }
 
 void