Permit MAC policies to instrument the access control decisions for

system accounting configuration and for nfsd server thread attach.
Policies might use this to protect the integrity or confidentiality
of accounting data, limit the ability to turn on or off accounting,
as well as to prevent inappropriately labeled threads from becoming nfs
server threads.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories

sys/kern/kern_acct.c

@@ -40,12 +40,15 @@
  * $FreeBSD$
  */
 
+#include "opt_mac.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/sysproto.h>
 #include <sys/proc.h>
+#include <sys/mac.h>
 #include <sys/mount.h>
 #include <sys/vnode.h>
 #include <sys/fcntl.h>
@@ -144,12 +147,25 @@ acct(td, uap)
 		if (error)
 			goto done2;
 		NDFREE(&nd, NDF_ONLY_PNBUF);
+#ifdef MAC
+		error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
+		if (error) {
+			vn_close(nd.ni_vp, flags, td->td_ucred, td);
+			goto done2;
+		}
+#endif
 		VOP_UNLOCK(nd.ni_vp, 0, td);
 		if (nd.ni_vp->v_type != VREG) {
 			vn_close(nd.ni_vp, flags, td->td_ucred, td);
 			error = EACCES;
 			goto done2;
 		}
+#ifdef MAC
+	} else {
+		error = mac_check_system_acct(td->td_ucred, NULL);
+		if (error)
+			goto done2;
+#endif
 	}
 
 	/*

sys/kern/kern_mac.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/modules/nfsserver/Makefile

@@ -5,6 +5,7 @@ KMOD=	nfsserver
 SRCS=	vnode_if.h \
 	nfs_serv.c nfs_srvsock.c nfs_srvcache.c nfs_srvsubs.c nfs_syscalls.c \
 	nfs_common.c \
+	opt_mac.h \
 	opt_nfs.h
 SRCS+=	opt_inet6.h
 NFS_INET6?=	1	# 0/1 - requires INET6 to be configured in kernel

sys/nfsserver/nfs_syscalls.c

@@ -41,6 +41,7 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_inet6.h"
+#include "opt_mac.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -50,6 +51,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/file.h>
 #include <sys/filedesc.h>
 #include <sys/vnode.h>
+#include <sys/mac.h>
 #include <sys/malloc.h>
 #include <sys/mount.h>
 #include <sys/proc.h>
@@ -137,10 +139,15 @@ nfssvc(struct thread *td, struct nfssvc_args *uap)
 	struct nfsd_args nfsdarg;
 	int error;
 
-	mtx_lock(&Giant);
+#ifdef MAC
+	error = mac_check_system_nfsd(td->td_ucred);
+	if (error)
+		return (error);
+#endif
 	error = suser(td);
 	if (error)
-		goto done2;
+		return (error);
+	mtx_lock(&Giant);
 	while (nfssvc_sockhead_flag & SLP_INIT) {
 		 nfssvc_sockhead_flag |= SLP_WANTINIT;
 		(void) tsleep((caddr_t)&nfssvc_sockhead, PSOCK, "nfsd init", 0);

sys/security/mac/mac_framework.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_framework.h

@@ -251,6 +251,8 @@ int	mac_check_socket_listen(struct ucred *cred, struct socket *so);
 int	mac_check_socket_receive(struct ucred *cred, struct socket *so);
 int	mac_check_socket_send(struct ucred *cred, struct socket *so);
 int	mac_check_socket_visible(struct ucred *cred, struct socket *so);
+int	mac_check_system_acct(struct ucred *cred, struct vnode *vp);
+int	mac_check_system_nfsd(struct ucred *cred);
 int	mac_check_system_reboot(struct ucred *cred, int howto);
 int	mac_check_system_settime(struct ucred *cred);
 int	mac_check_system_swapon(struct ucred *cred, struct vnode *vp);

sys/security/mac/mac_internal.h

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_net.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_pipe.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_policy.h

@@ -312,6 +312,9 @@ struct mac_policy_ops {
 		    struct socket *so, struct label *socketlabel);
 	int	(*mpo_check_socket_visible)(struct ucred *cred,
 		    struct socket *so, struct label *socketlabel);
+	int	(*mpo_check_system_acct)(struct ucred *cred,
+		    struct vnode *vp, struct label *vlabel);
+	int	(*mpo_check_system_nfsd)(struct ucred *cred);
 	int	(*mpo_check_system_reboot)(struct ucred *cred, int howto);
 	int	(*mpo_check_system_settime)(struct ucred *cred);
 	int	(*mpo_check_system_swapon)(struct ucred *cred,

sys/security/mac/mac_process.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_syscalls.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_system.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/security/mac/mac_vfs.c

@@ -2469,6 +2469,37 @@ mac_check_socket_visible(struct ucred *cred, struct socket *socket)
 	return (error);
 }
 
+int
+mac_check_system_acct(struct ucred *cred, struct vnode *vp)
+{
+	int error;
+
+	if (vp != NULL) {
+		ASSERT_VOP_LOCKED(vp, "mac_check_system_acct");
+	}
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_acct, cred, vp,
+	    vp != NULL ? &vp->v_label : NULL);
+
+	return (error);
+}
+
+int
+mac_check_system_nfsd(struct ucred *cred)
+{
+	int error;
+
+	if (!mac_enforce_system)
+		return (0);
+
+	MAC_CHECK(check_system_nfsd, cred);
+
+	return (error);
+}
+
 int
 mac_check_system_reboot(struct ucred *cred, int howto)
 {

sys/sys/mac.h

@@ -251,6 +251,8 @@ int	mac_check_socket_listen(struct ucred *cred, struct socket *so);
 int	mac_check_socket_receive(struct ucred *cred, struct socket *so);
 int	mac_check_socket_send(struct ucred *cred, struct socket *so);
 int	mac_check_socket_visible(struct ucred *cred, struct socket *so);
+int	mac_check_system_acct(struct ucred *cred, struct vnode *vp);
+int	mac_check_system_nfsd(struct ucred *cred);
 int	mac_check_system_reboot(struct ucred *cred, int howto);
 int	mac_check_system_settime(struct ucred *cred);
 int	mac_check_system_swapon(struct ucred *cred, struct vnode *vp);

sys/sys/mac_policy.h

@@ -312,6 +312,9 @@ struct mac_policy_ops {
 		    struct socket *so, struct label *socketlabel);
 	int	(*mpo_check_socket_visible)(struct ucred *cred,
 		    struct socket *so, struct label *socketlabel);
+	int	(*mpo_check_system_acct)(struct ucred *cred,
+		    struct vnode *vp, struct label *vlabel);
+	int	(*mpo_check_system_nfsd)(struct ucred *cred);
 	int	(*mpo_check_system_reboot)(struct ucred *cred, int howto);
 	int	(*mpo_check_system_settime)(struct ucred *cred);
 	int	(*mpo_check_system_swapon)(struct ucred *cred,