1100894Srwatson/*- 2189503Srwatson * Copyright (c) 1999-2002, 2008-2009 Robert N. M. Watson 3100894Srwatson * Copyright (c) 2001 Ilmar S. Habibulin 4126097Srwatson * Copyright (c) 2001-2003 Networks Associates Technology, Inc. 5172930Srwatson * Copyright (c) 2006 SPARTA, Inc. 6182063Srwatson * Copyright (c) 2008 Apple Inc. 7100894Srwatson * All rights reserved. 8100894Srwatson * 9100894Srwatson * This software was developed by Robert Watson and Ilmar Habibulin for the 10100894Srwatson * TrustedBSD Project. 11100894Srwatson * 12106392Srwatson * This software was developed for the FreeBSD Project in part by Network 13106392Srwatson * Associates Laboratories, the Security Research Division of Network 14106392Srwatson * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 15106392Srwatson * as part of the DARPA CHATS research program. 16100894Srwatson * 17172930Srwatson * This software was enhanced by SPARTA ISSO under SPAWAR contract 18172930Srwatson * N66001-04-C-6019 ("SEFOS"). 19172930Srwatson * 20189503Srwatson * This software was developed at the University of Cambridge Computer 21189503Srwatson * Laboratory with support from a grant from Google, Inc. 22189503Srwatson * 23100894Srwatson * Redistribution and use in source and binary forms, with or without 24100894Srwatson * modification, are permitted provided that the following conditions 25100894Srwatson * are met: 26100894Srwatson * 1. Redistributions of source code must retain the above copyright 27100894Srwatson * notice, this list of conditions and the following disclaimer. 28100894Srwatson * 2. Redistributions in binary form must reproduce the above copyright 29100894Srwatson * notice, this list of conditions and the following disclaimer in the 30100894Srwatson * documentation and/or other materials provided with the distribution. 31100894Srwatson * 32100894Srwatson * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 33100894Srwatson * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34100894Srwatson * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35100894Srwatson * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 36100894Srwatson * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37100894Srwatson * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38100894Srwatson * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39100894Srwatson * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40100894Srwatson * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41100894Srwatson * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42100894Srwatson * SUCH DAMAGE. 43100894Srwatson */ 44116182Sobrien 45116182Sobrien#include <sys/cdefs.h> 46116182Sobrien__FBSDID("$FreeBSD$"); 47116182Sobrien 48189503Srwatson#include "opt_kdtrace.h" 49100894Srwatson#include "opt_mac.h" 50101173Srwatson 51100894Srwatson#include <sys/param.h> 52106856Srwatson#include <sys/condvar.h> 53106468Srwatson#include <sys/imgact.h> 54100979Srwatson#include <sys/kernel.h> 55100979Srwatson#include <sys/lock.h> 56102949Sbde#include <sys/malloc.h> 57100979Srwatson#include <sys/mutex.h> 58100979Srwatson#include <sys/mac.h> 59100979Srwatson#include <sys/proc.h> 60116701Srwatson#include <sys/sbuf.h> 61189503Srwatson#include <sys/sdt.h> 62100979Srwatson#include <sys/systm.h> 63100979Srwatson#include <sys/vnode.h> 64100979Srwatson#include <sys/mount.h> 65100979Srwatson#include <sys/file.h> 66100979Srwatson#include <sys/namei.h> 67100979Srwatson#include <sys/sysctl.h> 68100894Srwatson 69100979Srwatson#include <vm/vm.h> 70100979Srwatson#include <vm/pmap.h> 71100979Srwatson#include <vm/vm_map.h> 72100979Srwatson#include <vm/vm_object.h> 73100979Srwatson 74163606Srwatson#include <security/mac/mac_framework.h> 75121361Srwatson#include <security/mac/mac_internal.h> 76165469Srwatson#include <security/mac/mac_policy.h> 77100979Srwatson 78103136Srwatsonstatic int mac_mmap_revocation = 1; 79103136SrwatsonSYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW, 80103136Srwatson &mac_mmap_revocation, 0, "Revoke mmap access to files on subject " 81103136Srwatson "relabel"); 82121361Srwatson 83101892Srwatsonstatic int mac_mmap_revocation_via_cow = 0; 84100979SrwatsonSYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW, 85100979Srwatson &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via " 86100979Srwatson "copy-on-write semantics, or by removing all write access"); 87100979Srwatson 88184412Srwatsonstatic void mac_proc_vm_revoke_recurse(struct thread *td, 89100979Srwatson struct ucred *cred, struct vm_map *map); 90100979Srwatson 91122524Srwatsonstatic struct label * 92122524Srwatsonmac_proc_label_alloc(void) 93122524Srwatson{ 94122524Srwatson struct label *label; 95122524Srwatson 96122524Srwatson label = mac_labelzone_alloc(M_WAITOK); 97191731Srwatson MAC_POLICY_PERFORM(proc_init_label, label); 98122524Srwatson return (label); 99122524Srwatson} 100122524Srwatson 101105694Srwatsonvoid 102172930Srwatsonmac_proc_init(struct proc *p) 103107105Srwatson{ 104107105Srwatson 105182063Srwatson if (mac_labeled & MPC_OBJECT_PROC) 106182063Srwatson p->p_label = mac_proc_label_alloc(); 107182063Srwatson else 108182063Srwatson p->p_label = NULL; 109107105Srwatson} 110107105Srwatson 111122524Srwatsonstatic void 112122524Srwatsonmac_proc_label_free(struct label *label) 113122524Srwatson{ 114122524Srwatson 115191731Srwatson MAC_POLICY_PERFORM_NOSLEEP(proc_destroy_label, label); 116122524Srwatson mac_labelzone_free(label); 117122524Srwatson} 118122524Srwatson 119105694Srwatsonvoid 120172930Srwatsonmac_proc_destroy(struct proc *p) 121107105Srwatson{ 122107105Srwatson 123182063Srwatson if (p->p_label != NULL) { 124182063Srwatson mac_proc_label_free(p->p_label); 125182063Srwatson p->p_label = NULL; 126182063Srwatson } 127107105Srwatson} 128107105Srwatson 129184407Srwatsonvoid 130104522Srwatsonmac_thread_userret(struct thread *td) 131104522Srwatson{ 132104522Srwatson 133191731Srwatson MAC_POLICY_PERFORM(thread_userret, td); 134104522Srwatson} 135104522Srwatson 136105988Srwatsonint 137122524Srwatsonmac_execve_enter(struct image_params *imgp, struct mac *mac_p) 138106468Srwatson{ 139122524Srwatson struct label *label; 140106468Srwatson struct mac mac; 141106468Srwatson char *buffer; 142106468Srwatson int error; 143106468Srwatson 144106468Srwatson if (mac_p == NULL) 145106468Srwatson return (0); 146106468Srwatson 147182063Srwatson if (!(mac_labeled & MPC_OBJECT_CRED)) 148182063Srwatson return (EINVAL); 149182063Srwatson 150106468Srwatson error = copyin(mac_p, &mac, sizeof(mac)); 151106468Srwatson if (error) 152106468Srwatson return (error); 153106468Srwatson 154106468Srwatson error = mac_check_structmac_consistent(&mac); 155106468Srwatson if (error) 156106468Srwatson return (error); 157106468Srwatson 158111119Simp buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK); 159106468Srwatson error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL); 160106468Srwatson if (error) { 161106468Srwatson free(buffer, M_MACTEMP); 162106468Srwatson return (error); 163106468Srwatson } 164106468Srwatson 165122524Srwatson label = mac_cred_label_alloc(); 166172930Srwatson error = mac_cred_internalize_label(label, buffer); 167106468Srwatson free(buffer, M_MACTEMP); 168106468Srwatson if (error) { 169122524Srwatson mac_cred_label_free(label); 170106468Srwatson return (error); 171106468Srwatson } 172122524Srwatson imgp->execlabel = label; 173106468Srwatson return (0); 174106468Srwatson} 175106468Srwatson 176100979Srwatsonvoid 177106468Srwatsonmac_execve_exit(struct image_params *imgp) 178100979Srwatson{ 179122524Srwatson if (imgp->execlabel != NULL) { 180122524Srwatson mac_cred_label_free(imgp->execlabel); 181122524Srwatson imgp->execlabel = NULL; 182122524Srwatson } 183106468Srwatson} 184100979Srwatson 185182063Srwatsonvoid 186182063Srwatsonmac_execve_interpreter_enter(struct vnode *interpvp, 187182063Srwatson struct label **interpvplabel) 188182063Srwatson{ 189182063Srwatson 190182063Srwatson if (mac_labeled & MPC_OBJECT_VNODE) { 191182063Srwatson *interpvplabel = mac_vnode_label_alloc(); 192182063Srwatson mac_vnode_copy_label(interpvp->v_label, *interpvplabel); 193182063Srwatson } else 194182063Srwatson *interpvplabel = NULL; 195182063Srwatson} 196182063Srwatson 197182063Srwatsonvoid 198182063Srwatsonmac_execve_interpreter_exit(struct label *interpvplabel) 199182063Srwatson{ 200182063Srwatson 201182063Srwatson if (interpvplabel != NULL) 202182063Srwatson mac_vnode_label_free(interpvplabel); 203182063Srwatson} 204182063Srwatson 205100979Srwatson/* 206100979Srwatson * When relabeling a process, call out to the policies for the maximum 207165425Srwatson * permission allowed for each object type we know about in its memory space, 208165425Srwatson * and revoke access (in the least surprising ways we know) when necessary. 209165425Srwatson * The process lock is not held here. 210100979Srwatson */ 211107271Srwatsonvoid 212184412Srwatsonmac_proc_vm_revoke(struct thread *td) 213100979Srwatson{ 214184412Srwatson struct ucred *cred; 215100979Srwatson 216184412Srwatson PROC_LOCK(td->td_proc); 217184412Srwatson cred = crhold(td->td_proc->p_ucred); 218184412Srwatson PROC_UNLOCK(td->td_proc); 219184412Srwatson 220100979Srwatson /* XXX freeze all other threads */ 221184412Srwatson mac_proc_vm_revoke_recurse(td, cred, 222100979Srwatson &td->td_proc->p_vmspace->vm_map); 223100979Srwatson /* XXX allow other threads to continue */ 224184412Srwatson 225184412Srwatson crfree(cred); 226100979Srwatson} 227100979Srwatson 228100979Srwatsonstatic __inline const char * 229100979Srwatsonprot2str(vm_prot_t prot) 230100979Srwatson{ 231100979Srwatson 232100979Srwatson switch (prot & VM_PROT_ALL) { 233100979Srwatson case VM_PROT_READ: 234100979Srwatson return ("r--"); 235100979Srwatson case VM_PROT_READ | VM_PROT_WRITE: 236100979Srwatson return ("rw-"); 237100979Srwatson case VM_PROT_READ | VM_PROT_EXECUTE: 238100979Srwatson return ("r-x"); 239100979Srwatson case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE: 240100979Srwatson return ("rwx"); 241100979Srwatson case VM_PROT_WRITE: 242100979Srwatson return ("-w-"); 243100979Srwatson case VM_PROT_EXECUTE: 244100979Srwatson return ("--x"); 245100979Srwatson case VM_PROT_WRITE | VM_PROT_EXECUTE: 246100979Srwatson return ("-wx"); 247100979Srwatson default: 248100979Srwatson return ("---"); 249100979Srwatson } 250100979Srwatson} 251100979Srwatson 252100979Srwatsonstatic void 253184412Srwatsonmac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred, 254100979Srwatson struct vm_map *map) 255100979Srwatson{ 256189013Skib vm_map_entry_t vme; 257150913Scsjp int vfslocked, result; 258104546Srwatson vm_prot_t revokeperms; 259151115Scsjp vm_object_t backing_object, object; 260100979Srwatson vm_ooffset_t offset; 261100979Srwatson struct vnode *vp; 262156225Stegge struct mount *mp; 263100979Srwatson 264103136Srwatson if (!mac_mmap_revocation) 265103136Srwatson return; 266103136Srwatson 267186397Salc vm_map_lock(map); 268100979Srwatson for (vme = map->header.next; vme != &map->header; vme = vme->next) { 269100979Srwatson if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) { 270184412Srwatson mac_proc_vm_revoke_recurse(td, cred, 271100979Srwatson vme->object.sub_map); 272100979Srwatson continue; 273100979Srwatson } 274100979Srwatson /* 275100979Srwatson * Skip over entries that obviously are not shared. 276100979Srwatson */ 277100979Srwatson if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) || 278100979Srwatson !vme->max_protection) 279100979Srwatson continue; 280100979Srwatson /* 281100979Srwatson * Drill down to the deepest backing object. 282100979Srwatson */ 283100979Srwatson offset = vme->offset; 284100979Srwatson object = vme->object.vm_object; 285100979Srwatson if (object == NULL) 286100979Srwatson continue; 287151115Scsjp VM_OBJECT_LOCK(object); 288151115Scsjp while ((backing_object = object->backing_object) != NULL) { 289151115Scsjp VM_OBJECT_LOCK(backing_object); 290150923Scsjp offset += object->backing_object_offset; 291151115Scsjp VM_OBJECT_UNLOCK(object); 292151115Scsjp object = backing_object; 293100979Srwatson } 294151115Scsjp VM_OBJECT_UNLOCK(object); 295100979Srwatson /* 296165425Srwatson * At the moment, vm_maps and objects aren't considered by 297165425Srwatson * the MAC system, so only things with backing by a normal 298165425Srwatson * object (read: vnodes) are checked. 299100979Srwatson */ 300100979Srwatson if (object->type != OBJT_VNODE) 301100979Srwatson continue; 302100979Srwatson vp = (struct vnode *)object->handle; 303150913Scsjp vfslocked = VFS_LOCK_GIANT(vp->v_mount); 304175202Sattilio vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 305104546Srwatson result = vme->max_protection; 306172930Srwatson mac_vnode_check_mmap_downgrade(cred, vp, &result); 307175294Sattilio VOP_UNLOCK(vp, 0); 308100979Srwatson /* 309165425Srwatson * Find out what maximum protection we may be allowing now 310165425Srwatson * but a policy needs to get removed. 311100979Srwatson */ 312100979Srwatson revokeperms = vme->max_protection & ~result; 313150913Scsjp if (!revokeperms) { 314150913Scsjp VFS_UNLOCK_GIANT(vfslocked); 315100979Srwatson continue; 316150913Scsjp } 317102949Sbde printf("pid %ld: revoking %s perms from %#lx:%ld " 318102949Sbde "(max %s/cur %s)\n", (long)td->td_proc->p_pid, 319102949Sbde prot2str(revokeperms), (u_long)vme->start, 320102949Sbde (long)(vme->end - vme->start), 321100979Srwatson prot2str(vme->max_protection), prot2str(vme->protection)); 322100979Srwatson /* 323100979Srwatson * This is the really simple case: if a map has more 324100979Srwatson * max_protection than is allowed, but it's not being 325165425Srwatson * actually used (that is, the current protection is still 326165425Srwatson * allowed), we can just wipe it out and do nothing more. 327100979Srwatson */ 328100979Srwatson if ((vme->protection & revokeperms) == 0) { 329100979Srwatson vme->max_protection -= revokeperms; 330100979Srwatson } else { 331100979Srwatson if (revokeperms & VM_PROT_WRITE) { 332100979Srwatson /* 333100979Srwatson * In the more complicated case, flush out all 334100979Srwatson * pending changes to the object then turn it 335100979Srwatson * copy-on-write. 336100979Srwatson */ 337100979Srwatson vm_object_reference(object); 338156225Stegge (void) vn_start_write(vp, &mp, V_WAIT); 339175202Sattilio vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 340113955Salc VM_OBJECT_LOCK(object); 341218345Salc vm_object_page_clean(object, offset, offset + 342218345Salc vme->end - vme->start, OBJPC_SYNC); 343113955Salc VM_OBJECT_UNLOCK(object); 344175294Sattilio VOP_UNLOCK(vp, 0); 345156225Stegge vn_finished_write(mp); 346100979Srwatson vm_object_deallocate(object); 347100979Srwatson /* 348100979Srwatson * Why bother if there's no read permissions 349100979Srwatson * anymore? For the rest, we need to leave 350100979Srwatson * the write permissions on for COW, or 351100979Srwatson * remove them entirely if configured to. 352100979Srwatson */ 353100979Srwatson if (!mac_mmap_revocation_via_cow) { 354100979Srwatson vme->max_protection &= ~VM_PROT_WRITE; 355100979Srwatson vme->protection &= ~VM_PROT_WRITE; 356100979Srwatson } if ((revokeperms & VM_PROT_READ) == 0) 357100979Srwatson vme->eflags |= MAP_ENTRY_COW | 358100979Srwatson MAP_ENTRY_NEEDS_COPY; 359100979Srwatson } 360100979Srwatson if (revokeperms & VM_PROT_EXECUTE) { 361100979Srwatson vme->max_protection &= ~VM_PROT_EXECUTE; 362100979Srwatson vme->protection &= ~VM_PROT_EXECUTE; 363100979Srwatson } 364100979Srwatson if (revokeperms & VM_PROT_READ) { 365100979Srwatson vme->max_protection = 0; 366100979Srwatson vme->protection = 0; 367100979Srwatson } 368100979Srwatson pmap_protect(map->pmap, vme->start, vme->end, 369100979Srwatson vme->protection & ~revokeperms); 370100979Srwatson vm_map_simplify_entry(map, vme); 371100979Srwatson } 372150913Scsjp VFS_UNLOCK_GIANT(vfslocked); 373100979Srwatson } 374186397Salc vm_map_unlock(map); 375100979Srwatson} 376100979Srwatson 377189503SrwatsonMAC_CHECK_PROBE_DEFINE2(proc_check_debug, "struct ucred *", "struct proc *"); 378189503Srwatson 379100979Srwatsonint 380172930Srwatsonmac_proc_check_debug(struct ucred *cred, struct proc *p) 381100979Srwatson{ 382100979Srwatson int error; 383100979Srwatson 384168955Srwatson PROC_LOCK_ASSERT(p, MA_OWNED); 385102103Srwatson 386191731Srwatson MAC_POLICY_CHECK_NOSLEEP(proc_check_debug, cred, p); 387189503Srwatson MAC_CHECK_PROBE2(proc_check_debug, error, cred, p); 388100979Srwatson 389100979Srwatson return (error); 390100979Srwatson} 391100979Srwatson 392189503SrwatsonMAC_CHECK_PROBE_DEFINE2(proc_check_sched, "struct ucred *", "struct proc *"); 393189503Srwatson 394100979Srwatsonint 395172930Srwatsonmac_proc_check_sched(struct ucred *cred, struct proc *p) 396100979Srwatson{ 397100979Srwatson int error; 398100979Srwatson 399168955Srwatson PROC_LOCK_ASSERT(p, MA_OWNED); 400102103Srwatson 401191731Srwatson MAC_POLICY_CHECK_NOSLEEP(proc_check_sched, cred, p); 402189503Srwatson MAC_CHECK_PROBE2(proc_check_sched, error, cred, p); 403100979Srwatson 404100979Srwatson return (error); 405100979Srwatson} 406100979Srwatson 407189503SrwatsonMAC_CHECK_PROBE_DEFINE3(proc_check_signal, "struct ucred *", "struct proc *", 408189503Srwatson "int"); 409189503Srwatson 410100979Srwatsonint 411172930Srwatsonmac_proc_check_signal(struct ucred *cred, struct proc *p, int signum) 412100979Srwatson{ 413100979Srwatson int error; 414100979Srwatson 415168955Srwatson PROC_LOCK_ASSERT(p, MA_OWNED); 416102103Srwatson 417191731Srwatson MAC_POLICY_CHECK_NOSLEEP(proc_check_signal, cred, p, signum); 418189503Srwatson MAC_CHECK_PROBE3(proc_check_signal, error, cred, p, signum); 419100979Srwatson 420100979Srwatson return (error); 421100979Srwatson} 422145147Srwatson 423189503SrwatsonMAC_CHECK_PROBE_DEFINE2(proc_check_wait, "struct ucred *", "struct proc *"); 424189503Srwatson 425145234Srwatsonint 426172930Srwatsonmac_proc_check_wait(struct ucred *cred, struct proc *p) 427145234Srwatson{ 428145234Srwatson int error; 429145234Srwatson 430168955Srwatson PROC_LOCK_ASSERT(p, MA_OWNED); 431145234Srwatson 432191731Srwatson MAC_POLICY_CHECK_NOSLEEP(proc_check_wait, cred, p); 433189503Srwatson MAC_CHECK_PROBE2(proc_check_wait, error, cred, p); 434145234Srwatson 435145234Srwatson return (error); 436145234Srwatson} 437