Modify the MAC Framework so that instead of embedding a (struct label)

in various kernel objects to represent security data, we embed a
(struct label *) pointer, which now references labels allocated using
a UMA zone (mac_label.c).  This allows the size and shape of struct
label to be varied without changing the size and shape of these kernel
objects, which become part of the frozen ABI with 5-STABLE.  This opens
the door for boot-time selection of the number of label slots, and hence
changes to the bound on the number of simultaneous labeled policies
at boot-time instead of compile-time.  This also makes it easier to
embed label references in new objects as required for locking/caching
with fine-grained network stack locking, such as inpcb structures.

This change also moves us further in the direction of hiding the
structure of kernel objects from MAC policy modules, not to mention
dramatically reducing the number of '&' symbols appearing in both the
MAC Framework and MAC policy modules, and improving readability.

While this results in minimal performance change with MAC enabled, it
will observably shrink the size of a number of critical kernel data
structures for the !MAC case, and should have a small (but measurable)
performance benefit (i.e., struct vnode, struct socket) do to memory
conservation and reduced cost of zeroing memory.

NOTE: Users of MAC must recompile their kernel and all MAC modules as a
result of this change.  Because this is an API change, third party
MAC modules will also need to be updated to make less use of the '&'
symbol.

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

1 files changed, 56 insertions, 56 deletions

diff --git a/sys/security/mac_lomac/mac_lomac.c b/sys/security/mac_lomac/mac_lomac.c
index c6261bf..be13a47 100644
--- a/sys/security/mac_lomac/mac_lomac.c
+++ b/sys/security/mac_lomac/mac_lomac.c
@@ -499,7 +499,7 @@ maybe_demote(struct mac_lomac *subjlabel, struct mac_lomac *objlabel,
 	struct proc *p;
 	pid_t pgid;
 
-	subj = PSLOT(&curthread->td_proc->p_label);
+	subj = PSLOT(curthread->td_proc->p_label);
 
 	p = curthread->td_proc;
 	mtx_lock(&subj->mtx);
@@ -941,7 +941,7 @@ mac_lomac_create_devfs_symlink(struct ucred *cred, struct mount *mp,
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(delabel);
 
 	mac_lomac_copy_single(source, dest);
@@ -953,7 +953,7 @@ mac_lomac_create_mount(struct ucred *cred, struct mount *mp,
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(mntlabel);
 	mac_lomac_copy_single(source, dest);
 	dest = SLOT(fslabel);
@@ -1082,7 +1082,7 @@ mac_lomac_create_vnode_extattr(struct ucred *cred, struct mount *mp,
 	buflen = sizeof(temp);
 	bzero(&temp, buflen);
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(vlabel);
 	dir = SLOT(dlabel);
 	if (dir->ml_flags & MAC_LOMAC_FLAG_AUX) {
@@ -1142,7 +1142,7 @@ mac_lomac_create_socket(struct ucred *cred, struct socket *socket,
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(socketlabel);
 
 	mac_lomac_copy_single(source, dest);
@@ -1154,7 +1154,7 @@ mac_lomac_create_pipe(struct ucred *cred, struct pipe *pipe,
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(pipelabel);
 
 	mac_lomac_copy_single(source, dest);
@@ -1231,7 +1231,7 @@ mac_lomac_create_bpfdesc(struct ucred *cred, struct bpf_d *bpf_d,
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred->cr_label);
+	source = SLOT(cred->cr_label);
 	dest = SLOT(bpflabel);
 
 	mac_lomac_copy_single(source, dest);
@@ -1453,8 +1453,8 @@ mac_lomac_create_cred(struct ucred *cred_parent, struct ucred *cred_child)
 {
 	struct mac_lomac *source, *dest;
 
-	source = SLOT(&cred_parent->cr_label);
-	dest = SLOT(&cred_child->cr_label);
+	source = SLOT(cred_parent->cr_label);
+	dest = SLOT(cred_child->cr_label);
 
 	mac_lomac_copy_single(source, dest);
 	mac_lomac_copy_range(source, dest);
@@ -1468,8 +1468,8 @@ mac_lomac_execve_transition(struct ucred *old, struct ucred *new,
 {
 	struct mac_lomac *source, *dest, *obj, *robj;
 
-	source = SLOT(&old->cr_label);
-	dest = SLOT(&new->cr_label);
+	source = SLOT(old->cr_label);
+	dest = SLOT(new->cr_label);
 	obj = SLOT(vnodelabel);
 	robj = interpvnodelabel != NULL ? SLOT(interpvnodelabel) : obj;
 
@@ -1507,7 +1507,7 @@ mac_lomac_execve_will_transition(struct ucred *old, struct vnode *vp,
 	if (!mac_lomac_enabled || !revocation_enabled)
 		return (0);
 
-	subj = SLOT(&old->cr_label);
+	subj = SLOT(old->cr_label);
 	obj = SLOT(vnodelabel);
 	robj = interpvnodelabel != NULL ? SLOT(interpvnodelabel) : obj;
 
@@ -1522,7 +1522,7 @@ mac_lomac_create_proc0(struct ucred *cred)
 {
 	struct mac_lomac *dest;
 
-	dest = SLOT(&cred->cr_label);
+	dest = SLOT(cred->cr_label);
 
 	mac_lomac_set_single(dest, MAC_LOMAC_TYPE_EQUAL, 0);
 	mac_lomac_set_range(dest, MAC_LOMAC_TYPE_LOW, 0, MAC_LOMAC_TYPE_HIGH,
@@ -1534,7 +1534,7 @@ mac_lomac_create_proc1(struct ucred *cred)
 {
 	struct mac_lomac *dest;
 
-	dest = SLOT(&cred->cr_label);
+	dest = SLOT(cred->cr_label);
 
 	mac_lomac_set_single(dest, MAC_LOMAC_TYPE_HIGH, 0);
 	mac_lomac_set_range(dest, MAC_LOMAC_TYPE_LOW, 0, MAC_LOMAC_TYPE_HIGH,
@@ -1547,7 +1547,7 @@ mac_lomac_relabel_cred(struct ucred *cred, struct label *newlabel)
 	struct mac_lomac *source, *dest;
 
 	source = SLOT(newlabel);
-	dest = SLOT(&cred->cr_label);
+	dest = SLOT(cred->cr_label);
 
 	try_relabel(source, dest);
 }
@@ -1578,7 +1578,7 @@ mac_lomac_check_cred_relabel(struct ucred *cred, struct label *newlabel)
 	struct mac_lomac *subj, *new;
 	int error;
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	new = SLOT(newlabel);
 
 	/*
@@ -1646,8 +1646,8 @@ mac_lomac_check_cred_visible(struct ucred *u1, struct ucred *u2)
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&u1->cr_label);
-	obj = SLOT(&u2->cr_label);
+	subj = SLOT(u1->cr_label);
+	obj = SLOT(u2->cr_label);
 
 	/* XXX: range */
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -1663,7 +1663,7 @@ mac_lomac_check_ifnet_relabel(struct ucred *cred, struct ifnet *ifnet,
 	struct mac_lomac *subj, *new;
 	int error;
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	new = SLOT(newlabel);
 
 	/*
@@ -1735,7 +1735,7 @@ mac_lomac_check_kld_load(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (mac_lomac_subject_privileged(subj))
@@ -1755,7 +1755,7 @@ mac_lomac_check_kld_unload(struct ucred *cred)
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 
 	if (mac_lomac_subject_privileged(subj))
 		return (EPERM);
@@ -1785,7 +1785,7 @@ mac_lomac_check_pipe_read(struct ucred *cred, struct pipe *pipe,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT((pipelabel));
 
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -1802,7 +1802,7 @@ mac_lomac_check_pipe_relabel(struct ucred *cred, struct pipe *pipe,
 	int error;
 
 	new = SLOT(newlabel);
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(pipelabel);
 
 	/*
@@ -1854,7 +1854,7 @@ mac_lomac_check_pipe_write(struct ucred *cred, struct pipe *pipe,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT((pipelabel));
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -1871,8 +1871,8 @@ mac_lomac_check_proc_debug(struct ucred *cred, struct proc *proc)
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
-	obj = SLOT(&proc->p_ucred->cr_label);
+	subj = SLOT(cred->cr_label);
+	obj = SLOT(proc->p_ucred->cr_label);
 
 	/* XXX: range checks */
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -1891,8 +1891,8 @@ mac_lomac_check_proc_sched(struct ucred *cred, struct proc *proc)
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
-	obj = SLOT(&proc->p_ucred->cr_label);
+	subj = SLOT(cred->cr_label);
+	obj = SLOT(proc->p_ucred->cr_label);
 
 	/* XXX: range checks */
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -1911,8 +1911,8 @@ mac_lomac_check_proc_signal(struct ucred *cred, struct proc *proc, int signum)
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
-	obj = SLOT(&proc->p_ucred->cr_label);
+	subj = SLOT(cred->cr_label);
+	obj = SLOT(proc->p_ucred->cr_label);
 
 	/* XXX: range checks */
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -1946,7 +1946,7 @@ mac_lomac_check_socket_relabel(struct ucred *cred, struct socket *socket,
 	int error;
 
 	new = SLOT(newlabel);
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(socketlabel);
 
 	/*
@@ -1998,7 +1998,7 @@ mac_lomac_check_socket_visible(struct ucred *cred, struct socket *socket,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(socketlabel);
 
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -2016,7 +2016,7 @@ mac_lomac_check_system_swapon(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (mac_lomac_subject_privileged(subj))
@@ -2037,7 +2037,7 @@ mac_lomac_check_system_sysctl(struct ucred *cred, int *name, u_int namelen,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 
 	/*
 	 * In general, treat sysctl variables as lomac/high, but also
@@ -2071,7 +2071,7 @@ mac_lomac_check_vnode_create(struct ucred *cred, struct vnode *dvp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(dlabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2093,7 +2093,7 @@ mac_lomac_check_vnode_delete(struct ucred *cred, struct vnode *dvp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(dlabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2116,7 +2116,7 @@ mac_lomac_check_vnode_deleteacl(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2135,7 +2135,7 @@ mac_lomac_check_vnode_link(struct ucred *cred, struct vnode *dvp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(dlabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2162,7 +2162,7 @@ mac_lomac_check_vnode_mmap(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (prot & VM_PROT_WRITE) {
@@ -2190,7 +2190,7 @@ mac_lomac_check_vnode_mprotect(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled || !revocation_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (prot & VM_PROT_WRITE) {
@@ -2218,7 +2218,7 @@ mac_lomac_check_vnode_mmap_downgrade(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled || !revocation_enabled)
 		return;
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2234,7 +2234,7 @@ mac_lomac_check_vnode_open(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	/* XXX privilege override for admin? */
@@ -2255,7 +2255,7 @@ mac_lomac_check_vnode_read(struct ucred *active_cred, struct ucred *file_cred,
 	if (!mac_lomac_enabled || !revocation_enabled)
 		return (0);
 
-	subj = SLOT(&active_cred->cr_label);
+	subj = SLOT(active_cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_dominate_single(obj, subj))
@@ -2273,7 +2273,7 @@ mac_lomac_check_vnode_relabel(struct ucred *cred, struct vnode *vp,
 
 	old = SLOT(vnodelabel);
 	new = SLOT(newlabel);
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 
 	/*
 	 * If there is a LOMAC label update for the vnode, it must be a
@@ -2350,7 +2350,7 @@ mac_lomac_check_vnode_rename_from(struct ucred *cred, struct vnode *dvp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(dlabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2374,7 +2374,7 @@ mac_lomac_check_vnode_rename_to(struct ucred *cred, struct vnode *dvp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(dlabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2399,7 +2399,7 @@ mac_lomac_check_vnode_revoke(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2417,7 +2417,7 @@ mac_lomac_check_vnode_setacl(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2436,7 +2436,7 @@ mac_lomac_check_vnode_setextattr(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2456,7 +2456,7 @@ mac_lomac_check_vnode_setflags(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2474,7 +2474,7 @@ mac_lomac_check_vnode_setmode(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2492,7 +2492,7 @@ mac_lomac_check_vnode_setowner(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2510,7 +2510,7 @@ mac_lomac_check_vnode_setutimes(struct ucred *cred, struct vnode *vp,
 	if (!mac_lomac_enabled)
 		return (0);
 
-	subj = SLOT(&cred->cr_label);
+	subj = SLOT(cred->cr_label);
 	obj = SLOT(vnodelabel);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2528,7 +2528,7 @@ mac_lomac_check_vnode_write(struct ucred *active_cred,
 	if (!mac_lomac_enabled || !revocation_enabled)
 		return (0);
 
-	subj = SLOT(&active_cred->cr_label);
+	subj = SLOT(active_cred->cr_label);
 	obj = SLOT(label);
 
 	if (!mac_lomac_subject_dominate(subj, obj))
@@ -2541,7 +2541,7 @@ static void
 mac_lomac_thread_userret(struct thread *td)
 {
 	struct proc *p = td->td_proc;
-	struct mac_lomac_proc *subj = PSLOT(&p->p_label);
+	struct mac_lomac_proc *subj = PSLOT(p->p_label);
 	struct ucred *newcred, *oldcred;
 	int dodrop;
 
@@ -2568,7 +2568,7 @@ mac_lomac_thread_userret(struct thread *td)
 		oldcred = p->p_ucred;
 		crcopy(newcred, oldcred);
 		crhold(newcred);
-		mac_lomac_copy(&subj->mac_lomac, SLOT(&newcred->cr_label));
+		mac_lomac_copy(&subj->mac_lomac, SLOT(newcred->cr_label));
 		p->p_ucred = newcred;
 		crfree(oldcred);
 		dodrop = 1;