Break contents of kern_mac.c out into two files following a repo-copy:

mac_framework.c   Contains basic MAC Framework functions, policy
                  registration, sysinits, etc.

mac_syscalls.c    Contains implementations of various MAC system calls,
                  including ENOSYS stubs when compiling without options
                  MAC.

Obtained from:	TrustedBSD Project

1 files changed, 0 insertions, 537 deletions

diff --git a/sys/security/mac/mac_syscalls.c b/sys/security/mac/mac_syscalls.c
index 7047db1..d5aa2b8 100644
--- a/sys/security/mac/mac_syscalls.c
+++ b/sys/security/mac/mac_syscalls.c
@@ -38,30 +38,6 @@
  * SUCH DAMAGE.
  */
 
-/*-
- * Framework for extensible kernel access control.  This file contains core
- * kernel infrastructure for the TrustedBSD MAC Framework, including policy
- * registration, versioning, locking, error composition operator, and system
- * calls.
- *
- * The MAC Framework implements three programming interfaces:
- *
- * - The kernel MAC interface, defined in mac_framework.h, and invoked
- *   throughout the kernel to request security decisions, notify of security
- *   related events, etc.
- *
- * - The MAC policy module interface, defined in mac_policy.h, which is
- *   implemented by MAC policy modules and invoked by the MAC Framework to
- *   forward kernel security requests and notifications to policy modules.
- *
- * - The user MAC API, defined in mac.h, which allows user programs to query
- *   and set label state on objects.
- *
- * The majority of the MAC Framework implementation may be found in
- * src/sys/security/mac.  Sample policy modules may be found in
- * src/sys/security/mac_*.
- */
-
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
@@ -112,516 +88,6 @@ __FBSDID("$FreeBSD$");
 #ifdef MAC
 
 /*
- * Root sysctl node for all MAC and MAC policy controls.
- */
-SYSCTL_NODE(_security, OID_AUTO, mac, CTLFLAG_RW, 0,
-    "TrustedBSD MAC policy controls");
-
-/*
- * Declare that the kernel provides MAC support, version 3 (FreeBSD 7.x).
- * This permits modules to refuse to be loaded if the necessary support isn't
- * present, even if it's pre-boot.
- */
-#define	MAC_VERSION	3
-static unsigned int	mac_version = MAC_VERSION;
-
-MODULE_VERSION(kernel_mac_support, MAC_VERSION);
-SYSCTL_UINT(_security_mac, OID_AUTO, version, CTLFLAG_RD, &mac_version, 0,
-    "");
-
-/*
- * Labels consist of a indexed set of "slots", which are allocated policies
- * as required.  The MAC Framework maintains a bitmask of slots allocated so
- * far to prevent reuse.  Slots cannot be reused, as the MAC Framework
- * guarantees that newly allocated slots in labels will be NULL unless
- * otherwise initialized, and because we do not have a mechanism to garbage
- * collect slots on policy unload.  As labeled policies tend to be statically
- * loaded during boot, and not frequently unloaded and reloaded, this is not
- * generally an issue.
- */
-#if MAC_MAX_SLOTS > 32
-#error "MAC_MAX_SLOTS too large"
-#endif
-
-static unsigned int mac_max_slots = MAC_MAX_SLOTS;
-static unsigned int mac_slot_offsets_free = (1 << MAC_MAX_SLOTS) - 1;
-SYSCTL_UINT(_security_mac, OID_AUTO, max_slots, CTLFLAG_RD, &mac_max_slots,
-    0, "");
-
-/*
- * Has the kernel started generating labeled objects yet?  All read/write
- * access to this variable is serialized during the boot process.  Following
- * the end of serialization, we don't update this flag; no locking.
- */
-int	mac_late = 0;
-
-/*
- * Flag to indicate whether or not we should allocate label storage for new
- * mbufs.  Since most dynamic policies we currently work with don't rely on
- * mbuf labeling, try to avoid paying the cost of mtag allocation unless
- * specifically notified of interest.  One result of this is that if a
- * dynamically loaded policy requests mbuf labels, it must be able to deal
- * with a NULL label being returned on any mbufs that were already in flight
- * when the policy was loaded.  Since the policy already has to deal with
- * uninitialized labels, this probably won't be a problem.  Note: currently
- * no locking.  Will this be a problem?
- *
- * In the future, we may want to allow objects to request labeling on a per-
- * object type basis, rather than globally for all objects.
- */
-#ifndef MAC_ALWAYS_LABEL_MBUF
-int	mac_labelmbufs = 0;
-#endif
-
-static int	mac_policy_register(struct mac_policy_conf *mpc);
-static int	mac_policy_unregister(struct mac_policy_conf *mpc);
-
-MALLOC_DEFINE(M_MACTEMP, "mactemp", "MAC temporary label storage");
-
-/*
- * mac_static_policy_list holds a list of policy modules that are not loaded
- * while the system is "live", and cannot be unloaded.  These policies can be
- * invoked without holding the busy count.
- *
- * mac_policy_list stores the list of dynamic policies.  A busy count is
- * maintained for the list, stored in mac_policy_busy.  The busy count is
- * protected by mac_policy_mtx; the list may be modified only while the busy
- * count is 0, requiring that the lock be held to prevent new references to
- * the list from being acquired.  For almost all operations, incrementing the
- * busy count is sufficient to guarantee consistency, as the list cannot be
- * modified while the busy count is elevated.  For a few special operations
- * involving a change to the list of active policies, the mtx itself must be
- * held.  A condition variable, mac_policy_cv, is used to signal potential
- * exclusive consumers that they should try to acquire the lock if a first
- * attempt at exclusive access fails.
- *
- * This design intentionally avoids fairness, and may starve attempts to
- * acquire an exclusive lock on a busy system.  This is required because we
- * do not ever want acquiring a read reference to perform an unbounded length
- * sleep.  Read references are acquired in ithreads, network isrs, etc, and
- * any unbounded blocking could lead quickly to deadlock.
- *
- * Another reason for never blocking on read references is that the MAC
- * Framework may recurse: if a policy calls a VOP, for example, this might
- * lead to vnode life cycle operations (such as init/destroy).
- *
- * If the kernel option MAC_STATIC has been compiled in, all locking becomes
- * a no-op, and the global list of policies is not allowed to change after
- * early boot.
- */
-#ifndef MAC_STATIC
-static struct mtx mac_policy_mtx;
-static struct cv mac_policy_cv;
-static int mac_policy_count;
-#endif
-struct mac_policy_list_head mac_policy_list;
-struct mac_policy_list_head mac_static_policy_list;
-
-/*
- * We manually invoke WITNESS_WARN() to allow Witness to generate warnings
- * even if we don't end up ever triggering the wait at run-time.  The
- * consumer of the exclusive interface must not hold any locks (other than
- * potentially Giant) since we may sleep for long (potentially indefinite)
- * periods of time waiting for the framework to become quiescent so that a
- * policy list change may be made.
- */
-void
-mac_policy_grab_exclusive(void)
-{
-
-#ifndef MAC_STATIC
-	if (!mac_late)
-		return;
-
-	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
- 	    "mac_policy_grab_exclusive() at %s:%d", __FILE__, __LINE__);
-	mtx_lock(&mac_policy_mtx);
-	while (mac_policy_count != 0)
-		cv_wait(&mac_policy_cv, &mac_policy_mtx);
-#endif
-}
-
-void
-mac_policy_assert_exclusive(void)
-{
-
-#ifndef MAC_STATIC
-	if (!mac_late)
-		return;
-
-	mtx_assert(&mac_policy_mtx, MA_OWNED);
-	KASSERT(mac_policy_count == 0,
-	    ("mac_policy_assert_exclusive(): not exclusive"));
-#endif
-}
-
-void
-mac_policy_release_exclusive(void)
-{
-
-#ifndef MAC_STATIC
-	if (!mac_late)
-		return;
-
-	KASSERT(mac_policy_count == 0,
-	    ("mac_policy_release_exclusive(): not exclusive"));
-	mtx_unlock(&mac_policy_mtx);
-	cv_signal(&mac_policy_cv);
-#endif
-}
-
-void
-mac_policy_list_busy(void)
-{
-
-#ifndef MAC_STATIC
-	if (!mac_late)
-		return;
-
-	mtx_lock(&mac_policy_mtx);
-	mac_policy_count++;
-	mtx_unlock(&mac_policy_mtx);
-#endif
-}
-
-int
-mac_policy_list_conditional_busy(void)
-{
-#ifndef MAC_STATIC
-	int ret;
-
-	if (!mac_late)
-		return (1);
-
-	mtx_lock(&mac_policy_mtx);
-	if (!LIST_EMPTY(&mac_policy_list)) {
-		mac_policy_count++;
-		ret = 1;
-	} else
-		ret = 0;
-	mtx_unlock(&mac_policy_mtx);
-	return (ret);
-#else
-	if (!mac_late)
-		return (1);
-
-	return (1);
-#endif
-}
-
-void
-mac_policy_list_unbusy(void)
-{
-
-#ifndef MAC_STATIC
-	if (!mac_late)
-		return;
-
-	mtx_lock(&mac_policy_mtx);
-	mac_policy_count--;
-	KASSERT(mac_policy_count >= 0, ("MAC_POLICY_LIST_LOCK"));
-	if (mac_policy_count == 0)
-		cv_signal(&mac_policy_cv);
-	mtx_unlock(&mac_policy_mtx);
-#endif
-}
-
-/*
- * Initialize the MAC subsystem, including appropriate SMP locks.
- */
-static void
-mac_init(void)
-{
-
-	LIST_INIT(&mac_static_policy_list);
-	LIST_INIT(&mac_policy_list);
-	mac_labelzone_init();
-
-#ifndef MAC_STATIC
-	mtx_init(&mac_policy_mtx, "mac_policy_mtx", NULL, MTX_DEF);
-	cv_init(&mac_policy_cv, "mac_policy_cv");
-#endif
-}
-
-/*
- * For the purposes of modules that want to know if they were loaded "early",
- * set the mac_late flag once we've processed modules either linked into the
- * kernel, or loaded before the kernel startup.
- */
-static void
-mac_late_init(void)
-{
-
-	mac_late = 1;
-}
-
-/*
- * After the policy list has changed, walk the list to update any global
- * flags.  Currently, we support only one flag, and it's conditionally
- * defined; as a result, the entire function is conditional.  Eventually, the
- * #else case might also iterate across the policies.
- */
-static void
-mac_policy_updateflags(void)
-{
-#ifndef MAC_ALWAYS_LABEL_MBUF
-	struct mac_policy_conf *tmpc;
-	int labelmbufs;
-
-	mac_policy_assert_exclusive();
-
-	labelmbufs = 0;
-	LIST_FOREACH(tmpc, &mac_static_policy_list, mpc_list) {
-		if (tmpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_LABELMBUFS)
-			labelmbufs++;
-	}
-	LIST_FOREACH(tmpc, &mac_policy_list, mpc_list) {
-		if (tmpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_LABELMBUFS)
-			labelmbufs++;
-	}
-	mac_labelmbufs = (labelmbufs != 0);
-#endif
-}
-
-/*
- * Allow MAC policy modules to register during boot, etc.
- */
-int
-mac_policy_modevent(module_t mod, int type, void *data)
-{
-	struct mac_policy_conf *mpc;
-	int error;
-
-	error = 0;
-	mpc = (struct mac_policy_conf *) data;
-
-#ifdef MAC_STATIC
-	if (mac_late) {
-		printf("mac_policy_modevent: MAC_STATIC and late\n");
-		return (EBUSY);
-	}
-#endif
-
-	switch (type) {
-	case MOD_LOAD:
-		if (mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_NOTLATE &&
-		    mac_late) {
-			printf("mac_policy_modevent: can't load %s policy "
-			    "after booting\n", mpc->mpc_name);
-			error = EBUSY;
-			break;
-		}
-		error = mac_policy_register(mpc);
-		break;
-	case MOD_UNLOAD:
-		/* Don't unregister the module if it was never registered. */
-		if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED)
-		    != 0)
-			error = mac_policy_unregister(mpc);
-		else
-			error = 0;
-		break;
-	default:
-		error = EOPNOTSUPP;
-		break;
-	}
-
-	return (error);
-}
-
-static int
-mac_policy_register(struct mac_policy_conf *mpc)
-{
-	struct mac_policy_conf *tmpc;
-	int error, slot, static_entry;
-
-	error = 0;
-
-	/*
-	 * We don't technically need exclusive access while !mac_late, but
-	 * hold it for assertion consistency.
-	 */
-	mac_policy_grab_exclusive();
-
-	/*
-	 * If the module can potentially be unloaded, or we're loading late,
-	 * we have to stick it in the non-static list and pay an extra
-	 * performance overhead.  Otherwise, we can pay a light locking cost
-	 * and stick it in the static list.
-	 */
-	static_entry = (!mac_late &&
-	    !(mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK));
-
-	if (static_entry) {
-		LIST_FOREACH(tmpc, &mac_static_policy_list, mpc_list) {
-			if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) {
-				error = EEXIST;
-				goto out;
-			}
-		}
-	} else {
-		LIST_FOREACH(tmpc, &mac_policy_list, mpc_list) {
-			if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) {
-				error = EEXIST;
-				goto out;
-			}
-		}
-	}
-	if (mpc->mpc_field_off != NULL) {
-		slot = ffs(mac_slot_offsets_free);
-		if (slot == 0) {
-			error = ENOMEM;
-			goto out;
-		}
-		slot--;
-		mac_slot_offsets_free &= ~(1 << slot);
-		*mpc->mpc_field_off = slot;
-	}
-	mpc->mpc_runtime_flags |= MPC_RUNTIME_FLAG_REGISTERED;
-
-	/*
-	 * If we're loading a MAC module after the framework has initialized,
-	 * it has to go into the dynamic list.  If we're loading it before
-	 * we've finished initializing, it can go into the static list with
-	 * weaker locker requirements.
-	 */
-	if (static_entry)
-		LIST_INSERT_HEAD(&mac_static_policy_list, mpc, mpc_list);
-	else
-		LIST_INSERT_HEAD(&mac_policy_list, mpc, mpc_list);
-
-	/*
-	 * Per-policy initialization.  Currently, this takes place under the
-	 * exclusive lock, so policies must not sleep in their init method.
-	 * In the future, we may want to separate "init" from "start", with
-	 * "init" occuring without the lock held.  Likewise, on tear-down,
-	 * breaking out "stop" from "destroy".
-	 */
-	if (mpc->mpc_ops->mpo_init != NULL)
-		(*(mpc->mpc_ops->mpo_init))(mpc);
-	mac_policy_updateflags();
-
-	printf("Security policy loaded: %s (%s)\n", mpc->mpc_fullname,
-	    mpc->mpc_name);
-
-out:
-	mac_policy_release_exclusive();
-	return (error);
-}
-
-static int
-mac_policy_unregister(struct mac_policy_conf *mpc)
-{
-
-	/*
-	 * If we fail the load, we may get a request to unload.  Check to see
-	 * if we did the run-time registration, and if not, silently succeed.
-	 */
-	mac_policy_grab_exclusive();
-	if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) == 0) {
-		mac_policy_release_exclusive();
-		return (0);
-	}
-#if 0
-	/*
-	 * Don't allow unloading modules with private data.
-	 */
-	if (mpc->mpc_field_off != NULL) {
-		MAC_POLICY_LIST_UNLOCK();
-		return (EBUSY);
-	}
-#endif
-	/*
-	 * Only allow the unload to proceed if the module is unloadable by
-	 * its own definition.
-	 */
-	if ((mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK) == 0) {
-		mac_policy_release_exclusive();
-		return (EBUSY);
-	}
-	if (mpc->mpc_ops->mpo_destroy != NULL)
-		(*(mpc->mpc_ops->mpo_destroy))(mpc);
-
-	LIST_REMOVE(mpc, mpc_list);
-	mpc->mpc_runtime_flags &= ~MPC_RUNTIME_FLAG_REGISTERED;
-	mac_policy_updateflags();
-
-	mac_policy_release_exclusive();
-
-	printf("Security policy unload: %s (%s)\n", mpc->mpc_fullname,
-	    mpc->mpc_name);
-
-	return (0);
-}
-
-/*
- * Define an error value precedence, and given two arguments, selects the
- * value with the higher precedence.
- */
-int
-mac_error_select(int error1, int error2)
-{
-
-	/* Certain decision-making errors take top priority. */
-	if (error1 == EDEADLK || error2 == EDEADLK)
-		return (EDEADLK);
-
-	/* Invalid arguments should be reported where possible. */
-	if (error1 == EINVAL || error2 == EINVAL)
-		return (EINVAL);
-
-	/* Precedence goes to "visibility", with both process and file. */
-	if (error1 == ESRCH || error2 == ESRCH)
-		return (ESRCH);
-
-	if (error1 == ENOENT || error2 == ENOENT)
-		return (ENOENT);
-
-	/* Precedence goes to DAC/MAC protections. */
-	if (error1 == EACCES || error2 == EACCES)
-		return (EACCES);
-
-	/* Precedence goes to privilege. */
-	if (error1 == EPERM || error2 == EPERM)
-		return (EPERM);
-
-	/* Precedence goes to error over success; otherwise, arbitrary. */
-	if (error1 != 0)
-		return (error1);
-	return (error2);
-}
-
-void
-mac_init_label(struct label *label)
-{
-
-	bzero(label, sizeof(*label));
-	label->l_flags = MAC_FLAG_INITIALIZED;
-}
-
-void
-mac_destroy_label(struct label *label)
-{
-
-	KASSERT(label->l_flags & MAC_FLAG_INITIALIZED,
-	    ("destroying uninitialized label"));
-
-	bzero(label, sizeof(*label));
-	/* implicit: label->l_flags &= ~MAC_FLAG_INITIALIZED; */
-}
-
-int
-mac_check_structmac_consistent(struct mac *mac)
-{
-
-	if (mac->m_buflen < 0 ||
-	    mac->m_buflen > MAC_MAX_LABEL_BUF_LEN)
-		return (EINVAL);
-
-	return (0);
-}
-
-/*
  * MPSAFE
  */
 int
@@ -1215,9 +681,6 @@ out:
 	return (error);
 }
 
-SYSINIT(mac, SI_SUB_MAC, SI_ORDER_FIRST, mac_init, NULL);
-SYSINIT(mac_late, SI_SUB_MAC_LATE, SI_ORDER_FIRST, mac_late_init, NULL);
-
 #else /* !MAC */
 
 int