2 * Copyright (c) 1999-2002, 2008-2009 Robert N. M. Watson
3 * Copyright (c) 2001 Ilmar S. Habibulin
4 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
5 * Copyright (c) 2006 SPARTA, Inc.
6 * Copyright (c) 2008 Apple Inc.
9 * This software was developed by Robert Watson and Ilmar Habibulin for the
12 * This software was developed for the FreeBSD Project in part by Network
13 * Associates Laboratories, the Security Research Division of Network
14 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
15 * as part of the DARPA CHATS research program.
17 * This software was enhanced by SPARTA ISSO under SPAWAR contract
18 * N66001-04-C-6019 ("SEFOS").
20 * This software was developed at the University of Cambridge Computer
21 * Laboratory with support from a grant from Google, Inc.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
50 #include <sys/param.h>
51 #include <sys/condvar.h>
52 #include <sys/imgact.h>
53 #include <sys/kernel.h>
55 #include <sys/malloc.h>
58 #include <sys/rwlock.h>
61 #include <sys/systm.h>
62 #include <sys/vnode.h>
63 #include <sys/mount.h>
65 #include <sys/namei.h>
66 #include <sys/sysctl.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_object.h>
73 #include <security/mac/mac_framework.h>
74 #include <security/mac/mac_internal.h>
75 #include <security/mac/mac_policy.h>
77 static int mac_mmap_revocation = 1;
78 SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
79 &mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
82 static int mac_mmap_revocation_via_cow = 0;
83 SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
84 &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
85 "copy-on-write semantics, or by removing all write access");
87 static void mac_proc_vm_revoke_recurse(struct thread *td,
88 struct ucred *cred, struct vm_map *map);
91 mac_proc_label_alloc(void)
95 label = mac_labelzone_alloc(M_WAITOK);
96 MAC_POLICY_PERFORM(proc_init_label, label);
101 mac_proc_init(struct proc *p)
104 if (mac_labeled & MPC_OBJECT_PROC)
105 p->p_label = mac_proc_label_alloc();
111 mac_proc_label_free(struct label *label)
114 MAC_POLICY_PERFORM_NOSLEEP(proc_destroy_label, label);
115 mac_labelzone_free(label);
119 mac_proc_destroy(struct proc *p)
122 if (p->p_label != NULL) {
123 mac_proc_label_free(p->p_label);
129 mac_thread_userret(struct thread *td)
132 MAC_POLICY_PERFORM(thread_userret, td);
136 mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
146 if (!(mac_labeled & MPC_OBJECT_CRED))
149 error = copyin(mac_p, &mac, sizeof(mac));
153 error = mac_check_structmac_consistent(&mac);
157 buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
158 error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
160 free(buffer, M_MACTEMP);
164 label = mac_cred_label_alloc();
165 error = mac_cred_internalize_label(label, buffer);
166 free(buffer, M_MACTEMP);
168 mac_cred_label_free(label);
171 imgp->execlabel = label;
176 mac_execve_exit(struct image_params *imgp)
178 if (imgp->execlabel != NULL) {
179 mac_cred_label_free(imgp->execlabel);
180 imgp->execlabel = NULL;
185 mac_execve_interpreter_enter(struct vnode *interpvp,
186 struct label **interpvplabel)
189 if (mac_labeled & MPC_OBJECT_VNODE) {
190 *interpvplabel = mac_vnode_label_alloc();
191 mac_vnode_copy_label(interpvp->v_label, *interpvplabel);
193 *interpvplabel = NULL;
197 mac_execve_interpreter_exit(struct label *interpvplabel)
200 if (interpvplabel != NULL)
201 mac_vnode_label_free(interpvplabel);
205 * When relabeling a process, call out to the policies for the maximum
206 * permission allowed for each object type we know about in its memory space,
207 * and revoke access (in the least surprising ways we know) when necessary.
208 * The process lock is not held here.
211 mac_proc_vm_revoke(struct thread *td)
215 PROC_LOCK(td->td_proc);
216 cred = crhold(td->td_proc->p_ucred);
217 PROC_UNLOCK(td->td_proc);
219 /* XXX freeze all other threads */
220 mac_proc_vm_revoke_recurse(td, cred,
221 &td->td_proc->p_vmspace->vm_map);
222 /* XXX allow other threads to continue */
227 static __inline const char *
228 prot2str(vm_prot_t prot)
231 switch (prot & VM_PROT_ALL) {
234 case VM_PROT_READ | VM_PROT_WRITE:
236 case VM_PROT_READ | VM_PROT_EXECUTE:
238 case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
242 case VM_PROT_EXECUTE:
244 case VM_PROT_WRITE | VM_PROT_EXECUTE:
252 mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
255 vm_map_entry_t prev, vme;
257 vm_prot_t revokeperms;
258 vm_object_t backing_object, object;
263 if (!mac_mmap_revocation)
268 for (vme = vm_map_entry_first(map); vme != &map->header;
269 prev = vme, vme = vm_map_entry_succ(prev)) {
270 if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
271 mac_proc_vm_revoke_recurse(td, cred,
272 vme->object.sub_map);
276 * Skip over entries that obviously are not shared.
278 if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
279 !vme->max_protection)
282 * Drill down to the deepest backing object.
284 offset = vme->offset;
285 object = vme->object.vm_object;
288 VM_OBJECT_RLOCK(object);
289 while ((backing_object = object->backing_object) != NULL) {
290 VM_OBJECT_RLOCK(backing_object);
291 offset += object->backing_object_offset;
292 VM_OBJECT_RUNLOCK(object);
293 object = backing_object;
295 VM_OBJECT_RUNLOCK(object);
297 * At the moment, vm_maps and objects aren't considered by
298 * the MAC system, so only things with backing by a normal
299 * object (read: vnodes) are checked.
301 if (object->type != OBJT_VNODE)
303 vp = (struct vnode *)object->handle;
304 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
305 result = vme->max_protection;
306 mac_vnode_check_mmap_downgrade(cred, vp, &result);
309 * Find out what maximum protection we may be allowing now
310 * but a policy needs to get removed.
312 revokeperms = vme->max_protection & ~result;
315 printf("pid %ld: revoking %s perms from %#lx:%ld "
316 "(max %s/cur %s)\n", (long)td->td_proc->p_pid,
317 prot2str(revokeperms), (u_long)vme->start,
318 (long)(vme->end - vme->start),
319 prot2str(vme->max_protection), prot2str(vme->protection));
321 * This is the really simple case: if a map has more
322 * max_protection than is allowed, but it's not being
323 * actually used (that is, the current protection is still
324 * allowed), we can just wipe it out and do nothing more.
326 if ((vme->protection & revokeperms) == 0) {
327 vme->max_protection -= revokeperms;
329 if (revokeperms & VM_PROT_WRITE) {
331 * In the more complicated case, flush out all
332 * pending changes to the object then turn it
335 vm_object_reference(object);
336 (void) vn_start_write(vp, &mp, V_WAIT);
337 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
338 VM_OBJECT_WLOCK(object);
339 vm_object_page_clean(object, offset, offset +
340 vme->end - vme->start, OBJPC_SYNC);
341 VM_OBJECT_WUNLOCK(object);
343 vn_finished_write(mp);
344 vm_object_deallocate(object);
346 * Why bother if there's no read permissions
347 * anymore? For the rest, we need to leave
348 * the write permissions on for COW, or
349 * remove them entirely if configured to.
351 if (!mac_mmap_revocation_via_cow) {
352 vme->max_protection &= ~VM_PROT_WRITE;
353 vme->protection &= ~VM_PROT_WRITE;
354 } if ((revokeperms & VM_PROT_READ) == 0)
355 vme->eflags |= MAP_ENTRY_COW |
356 MAP_ENTRY_NEEDS_COPY;
358 if (revokeperms & VM_PROT_EXECUTE) {
359 vme->max_protection &= ~VM_PROT_EXECUTE;
360 vme->protection &= ~VM_PROT_EXECUTE;
362 if (revokeperms & VM_PROT_READ) {
363 vme->max_protection = 0;
366 pmap_protect(map->pmap, vme->start, vme->end,
367 vme->protection & ~revokeperms);
368 vm_map_try_merge_entries(map, prev, vme);
374 MAC_CHECK_PROBE_DEFINE2(proc_check_debug, "struct ucred *", "struct proc *");
377 mac_proc_check_debug(struct ucred *cred, struct proc *p)
381 PROC_LOCK_ASSERT(p, MA_OWNED);
383 MAC_POLICY_CHECK_NOSLEEP(proc_check_debug, cred, p);
384 MAC_CHECK_PROBE2(proc_check_debug, error, cred, p);
389 MAC_CHECK_PROBE_DEFINE2(proc_check_sched, "struct ucred *", "struct proc *");
392 mac_proc_check_sched(struct ucred *cred, struct proc *p)
396 PROC_LOCK_ASSERT(p, MA_OWNED);
398 MAC_POLICY_CHECK_NOSLEEP(proc_check_sched, cred, p);
399 MAC_CHECK_PROBE2(proc_check_sched, error, cred, p);
404 MAC_CHECK_PROBE_DEFINE3(proc_check_signal, "struct ucred *", "struct proc *",
408 mac_proc_check_signal(struct ucred *cred, struct proc *p, int signum)
412 PROC_LOCK_ASSERT(p, MA_OWNED);
414 MAC_POLICY_CHECK_NOSLEEP(proc_check_signal, cred, p, signum);
415 MAC_CHECK_PROBE3(proc_check_signal, error, cred, p, signum);
420 MAC_CHECK_PROBE_DEFINE2(proc_check_wait, "struct ucred *", "struct proc *");
423 mac_proc_check_wait(struct ucred *cred, struct proc *p)
427 PROC_LOCK_ASSERT(p, MA_OWNED);
429 MAC_POLICY_CHECK_NOSLEEP(proc_check_wait, cred, p);
430 MAC_CHECK_PROBE2(proc_check_wait, error, cred, p);