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- /*-
- * Copyright (c) 1999-2002, 2008-2009 Robert N. M. Watson
- * Copyright (c) 2001 Ilmar S. Habibulin
- * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
- * Copyright (c) 2006 SPARTA, Inc.
- * Copyright (c) 2008 Apple Inc.
- * All rights reserved.
- *
- * This software was developed by Robert Watson and Ilmar Habibulin for the
- * TrustedBSD Project.
- *
- * This software was developed for the FreeBSD Project in part by Network
- * Associates Laboratories, the Security Research Division of Network
- * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
- * as part of the DARPA CHATS research program.
- *
- * This software was enhanced by SPARTA ISSO under SPAWAR contract
- * N66001-04-C-6019 ("SEFOS").
- *
- * This software was developed at the University of Cambridge Computer
- * Laboratory with support from a grant from Google, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #include <sys/cdefs.h>
- #include "opt_mac.h"
- #include <sys/param.h>
- #include <sys/condvar.h>
- #include <sys/imgact.h>
- #include <sys/kernel.h>
- #include <sys/lock.h>
- #include <sys/malloc.h>
- #include <sys/mac.h>
- #include <sys/proc.h>
- #include <sys/rwlock.h>
- #include <sys/sbuf.h>
- #include <sys/sdt.h>
- #include <sys/systm.h>
- #include <sys/vnode.h>
- #include <sys/mount.h>
- #include <sys/file.h>
- #include <sys/namei.h>
- #include <sys/sysctl.h>
- #include <vm/vm.h>
- #include <vm/pmap.h>
- #include <vm/vm_map.h>
- #include <vm/vm_object.h>
- #include <security/mac/mac_framework.h>
- #include <security/mac/mac_internal.h>
- #include <security/mac/mac_policy.h>
- static int mac_mmap_revocation = 1;
- SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
- &mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
- "relabel");
- static int mac_mmap_revocation_via_cow = 0;
- SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
- &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
- "copy-on-write semantics, or by removing all write access");
- static void mac_proc_vm_revoke_recurse(struct thread *td,
- struct ucred *cred, struct vm_map *map);
- static struct label *
- mac_proc_label_alloc(void)
- {
- struct label *label;
- label = mac_labelzone_alloc(M_WAITOK);
- MAC_POLICY_PERFORM(proc_init_label, label);
- return (label);
- }
- void
- mac_proc_init(struct proc *p)
- {
- if (mac_labeled & MPC_OBJECT_PROC)
- p->p_label = mac_proc_label_alloc();
- else
- p->p_label = NULL;
- }
- static void
- mac_proc_label_free(struct label *label)
- {
- MAC_POLICY_PERFORM_NOSLEEP(proc_destroy_label, label);
- mac_labelzone_free(label);
- }
- void
- mac_proc_destroy(struct proc *p)
- {
- if (p->p_label != NULL) {
- mac_proc_label_free(p->p_label);
- p->p_label = NULL;
- }
- }
- void
- mac_thread_userret(struct thread *td)
- {
- MAC_POLICY_PERFORM(thread_userret, td);
- }
- int
- mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
- {
- struct label *label;
- struct mac mac;
- char *buffer;
- int error;
- if (mac_p == NULL)
- return (0);
- if (!(mac_labeled & MPC_OBJECT_CRED))
- return (EINVAL);
- error = copyin(mac_p, &mac, sizeof(mac));
- if (error)
- return (error);
- error = mac_check_structmac_consistent(&mac);
- if (error)
- return (error);
- buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
- error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
- if (error) {
- free(buffer, M_MACTEMP);
- return (error);
- }
- label = mac_cred_label_alloc();
- error = mac_cred_internalize_label(label, buffer);
- free(buffer, M_MACTEMP);
- if (error) {
- mac_cred_label_free(label);
- return (error);
- }
- imgp->execlabel = label;
- return (0);
- }
- void
- mac_execve_exit(struct image_params *imgp)
- {
- if (imgp->execlabel != NULL) {
- mac_cred_label_free(imgp->execlabel);
- imgp->execlabel = NULL;
- }
- }
- void
- mac_execve_interpreter_enter(struct vnode *interpvp,
- struct label **interpvplabel)
- {
- if (mac_labeled & MPC_OBJECT_VNODE) {
- *interpvplabel = mac_vnode_label_alloc();
- mac_vnode_copy_label(interpvp->v_label, *interpvplabel);
- } else
- *interpvplabel = NULL;
- }
- void
- mac_execve_interpreter_exit(struct label *interpvplabel)
- {
- if (interpvplabel != NULL)
- mac_vnode_label_free(interpvplabel);
- }
- /*
- * When relabeling a process, call out to the policies for the maximum
- * permission allowed for each object type we know about in its memory space,
- * and revoke access (in the least surprising ways we know) when necessary.
- * The process lock is not held here.
- */
- void
- mac_proc_vm_revoke(struct thread *td)
- {
- struct ucred *cred;
- PROC_LOCK(td->td_proc);
- cred = crhold(td->td_proc->p_ucred);
- PROC_UNLOCK(td->td_proc);
- /* XXX freeze all other threads */
- mac_proc_vm_revoke_recurse(td, cred,
- &td->td_proc->p_vmspace->vm_map);
- /* XXX allow other threads to continue */
- crfree(cred);
- }
- static __inline const char *
- prot2str(vm_prot_t prot)
- {
- switch (prot & VM_PROT_ALL) {
- case VM_PROT_READ:
- return ("r--");
- case VM_PROT_READ | VM_PROT_WRITE:
- return ("rw-");
- case VM_PROT_READ | VM_PROT_EXECUTE:
- return ("r-x");
- case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
- return ("rwx");
- case VM_PROT_WRITE:
- return ("-w-");
- case VM_PROT_EXECUTE:
- return ("--x");
- case VM_PROT_WRITE | VM_PROT_EXECUTE:
- return ("-wx");
- default:
- return ("---");
- }
- }
- static void
- mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
- struct vm_map *map)
- {
- vm_map_entry_t prev, vme;
- int result;
- vm_prot_t revokeperms;
- vm_object_t backing_object, object;
- vm_ooffset_t offset;
- struct vnode *vp;
- struct mount *mp;
- if (!mac_mmap_revocation)
- return;
- prev = &map->header;
- vm_map_lock(map);
- for (vme = vm_map_entry_first(map); vme != &map->header;
- prev = vme, vme = vm_map_entry_succ(prev)) {
- if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
- mac_proc_vm_revoke_recurse(td, cred,
- vme->object.sub_map);
- continue;
- }
- /*
- * Skip over entries that obviously are not shared.
- */
- if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
- !vme->max_protection)
- continue;
- /*
- * Drill down to the deepest backing object.
- */
- offset = vme->offset;
- object = vme->object.vm_object;
- if (object == NULL)
- continue;
- VM_OBJECT_RLOCK(object);
- while ((backing_object = object->backing_object) != NULL) {
- VM_OBJECT_RLOCK(backing_object);
- offset += object->backing_object_offset;
- VM_OBJECT_RUNLOCK(object);
- object = backing_object;
- }
- VM_OBJECT_RUNLOCK(object);
- /*
- * At the moment, vm_maps and objects aren't considered by
- * the MAC system, so only things with backing by a normal
- * object (read: vnodes) are checked.
- */
- if (object->type != OBJT_VNODE)
- continue;
- vp = (struct vnode *)object->handle;
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- result = vme->max_protection;
- mac_vnode_check_mmap_downgrade(cred, vp, &result);
- VOP_UNLOCK(vp);
- /*
- * Find out what maximum protection we may be allowing now
- * but a policy needs to get removed.
- */
- revokeperms = vme->max_protection & ~result;
- if (!revokeperms)
- continue;
- printf("pid %ld: revoking %s perms from %#lx:%ld "
- "(max %s/cur %s)\n", (long)td->td_proc->p_pid,
- prot2str(revokeperms), (u_long)vme->start,
- (long)(vme->end - vme->start),
- prot2str(vme->max_protection), prot2str(vme->protection));
- /*
- * This is the really simple case: if a map has more
- * max_protection than is allowed, but it's not being
- * actually used (that is, the current protection is still
- * allowed), we can just wipe it out and do nothing more.
- */
- if ((vme->protection & revokeperms) == 0) {
- vme->max_protection -= revokeperms;
- } else {
- if (revokeperms & VM_PROT_WRITE) {
- /*
- * In the more complicated case, flush out all
- * pending changes to the object then turn it
- * copy-on-write.
- */
- vm_object_reference(object);
- (void) vn_start_write(vp, &mp, V_WAIT);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- VM_OBJECT_WLOCK(object);
- vm_object_page_clean(object, offset, offset +
- vme->end - vme->start, OBJPC_SYNC);
- VM_OBJECT_WUNLOCK(object);
- VOP_UNLOCK(vp);
- vn_finished_write(mp);
- vm_object_deallocate(object);
- /*
- * Why bother if there's no read permissions
- * anymore? For the rest, we need to leave
- * the write permissions on for COW, or
- * remove them entirely if configured to.
- */
- if (!mac_mmap_revocation_via_cow) {
- vme->max_protection &= ~VM_PROT_WRITE;
- vme->protection &= ~VM_PROT_WRITE;
- } if ((revokeperms & VM_PROT_READ) == 0)
- vme->eflags |= MAP_ENTRY_COW |
- MAP_ENTRY_NEEDS_COPY;
- }
- if (revokeperms & VM_PROT_EXECUTE) {
- vme->max_protection &= ~VM_PROT_EXECUTE;
- vme->protection &= ~VM_PROT_EXECUTE;
- }
- if (revokeperms & VM_PROT_READ) {
- vme->max_protection = 0;
- vme->protection = 0;
- }
- pmap_protect(map->pmap, vme->start, vme->end,
- vme->protection & ~revokeperms);
- vm_map_try_merge_entries(map, prev, vme);
- }
- }
- vm_map_unlock(map);
- }
- MAC_CHECK_PROBE_DEFINE2(proc_check_debug, "struct ucred *", "struct proc *");
- int
- mac_proc_check_debug(struct ucred *cred, struct proc *p)
- {
- int error;
- PROC_LOCK_ASSERT(p, MA_OWNED);
- MAC_POLICY_CHECK_NOSLEEP(proc_check_debug, cred, p);
- MAC_CHECK_PROBE2(proc_check_debug, error, cred, p);
- return (error);
- }
- MAC_CHECK_PROBE_DEFINE2(proc_check_sched, "struct ucred *", "struct proc *");
- int
- mac_proc_check_sched(struct ucred *cred, struct proc *p)
- {
- int error;
- PROC_LOCK_ASSERT(p, MA_OWNED);
- MAC_POLICY_CHECK_NOSLEEP(proc_check_sched, cred, p);
- MAC_CHECK_PROBE2(proc_check_sched, error, cred, p);
- return (error);
- }
- MAC_CHECK_PROBE_DEFINE3(proc_check_signal, "struct ucred *", "struct proc *",
- "int");
- int
- mac_proc_check_signal(struct ucred *cred, struct proc *p, int signum)
- {
- int error;
- PROC_LOCK_ASSERT(p, MA_OWNED);
- MAC_POLICY_CHECK_NOSLEEP(proc_check_signal, cred, p, signum);
- MAC_CHECK_PROBE3(proc_check_signal, error, cred, p, signum);
- return (error);
- }
- MAC_CHECK_PROBE_DEFINE2(proc_check_wait, "struct ucred *", "struct proc *");
- int
- mac_proc_check_wait(struct ucred *cred, struct proc *p)
- {
- int error;
- PROC_LOCK_ASSERT(p, MA_OWNED);
- MAC_POLICY_CHECK_NOSLEEP(proc_check_wait, cred, p);
- MAC_CHECK_PROBE2(proc_check_wait, error, cred, p);
- return (error);
- }
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