security/mac_process.c

   1 /*
   2  * Copyright (c) 2007-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*-
  30  * Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
  31  * Copyright (c) 2001 Ilmar S. Habibulin
  32  * Copyright (c) 2001, 2002, 2003, 2004 Networks Associates Technology, Inc.
  33  *
  34  * This software was developed by Robert Watson and Ilmar Habibulin for the
  35  * TrustedBSD Project.
  36  *
  37  * This software was developed for the FreeBSD Project in part by Network
  38  * Associates Laboratories, the Security Research Division of Network
  39  * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
  40  * as part of the DARPA CHATS research program.
  41  *
  42  * Redistribution and use in source and binary forms, with or without
  43  * modification, are permitted provided that the following conditions
  44  * are met:
  45  * 1. Redistributions of source code must retain the above copyright
  46  *    notice, this list of conditions and the following disclaimer.
  47  * 2. Redistributions in binary form must reproduce the above copyright
  48  *    notice, this list of conditions and the following disclaimer in the
  49  *    documentation and/or other materials provided with the distribution.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  */
  64
  65 #include <string.h>
  66 #include <sys/param.h>
  67 #include <sys/ucred.h>
  68 #include <sys/malloc.h>
  69 #include <sys/sbuf.h>
  70 #include <sys/vnode.h>
  71 #include <sys/proc.h>
  72 #include <sys/proc_internal.h>
  73 #include <sys/kauth.h>
  74 #include <sys/imgact.h>
  75 #include <mach/mach_types.h>
  76 #include <kern/task.h>
  77
  78 #include <security/mac_internal.h>
  79 #include <security/mac_mach_internal.h>
  80
  81 #include <bsd/security/audit/audit.h>
  82
  83 struct label *
  84 mac_cred_label_alloc(void)
  85 {
  86         struct label *label;
  87
  88         label = mac_labelzone_alloc(MAC_WAITOK);
  89         if (label == NULL)
  90                 return (NULL);
  91         MAC_PERFORM(cred_label_init, label);
  92         return (label);
  93 }
  94
  95 void
  96 mac_cred_label_init(struct ucred *cred)
  97 {
  98         cred->cr_label = mac_cred_label_alloc();
  99 }
 100
 101 void
 102 mac_cred_label_free(struct label *label)
 103 {
 104         MAC_PERFORM(cred_label_destroy, label);
 105         mac_labelzone_free(label);
 106 }
 107
 108 int
 109 mac_cred_label_compare(struct label *a, struct label *b)
 110 {
 111         return (bcmp(a, b, sizeof (*a)) == 0);
 112 }
 113
 114 int
 115 mac_cred_label_externalize_audit(struct proc *p, struct mac *mac)
 116 {
 117         kauth_cred_t cr;
 118         int error;
 119
 120         cr = kauth_cred_proc_ref(p);
 121
 122         error = MAC_EXTERNALIZE_AUDIT(cred, cr->cr_label,
 123             mac->m_string, mac->m_buflen);
 124
 125         kauth_cred_unref(&cr);
 126         return (error);
 127 }
 128
 129 void
 130 mac_cred_label_destroy(kauth_cred_t cred)
 131 {
 132
 133         mac_cred_label_free(cred->cr_label);
 134         cred->cr_label = NULL;
 135 }
 136
 137 int
 138 mac_cred_label_externalize(struct label *label, char *elements,
 139     char *outbuf, size_t outbuflen, int flags __unused)
 140 {
 141         int error = 0;
 142
 143         error = MAC_EXTERNALIZE(cred, label, elements, outbuf, outbuflen);
 144
 145         return (error);
 146 }
 147
 148 int
 149 mac_cred_label_internalize(struct label *label, char *string)
 150 {
 151         int error;
 152
 153         error = MAC_INTERNALIZE(cred, label, string);
 154
 155         return (error);
 156 }
 157
 158 /*
 159  * By default, fork just adds a reference to the parent
 160  * credential.  Policies may need to know about this reference
 161  * if they are tracking exit calls to know when to free the
 162  * label.
 163  */
 164 void
 165 mac_cred_label_associate_fork(kauth_cred_t cred, proc_t proc)
 166 {
 167         MAC_PERFORM(cred_label_associate_fork, cred, proc);
 168 }
 169
 170 /*
 171  * Initialize MAC label for the first kernel process, from which other
 172  * kernel processes and threads are spawned.
 173  */
 174 void
 175 mac_cred_label_associate_kernel(kauth_cred_t cred)
 176 {
 177
 178         MAC_PERFORM(cred_label_associate_kernel, cred);
 179 }
 180
 181 /*
 182  * Initialize MAC label for the first userland process, from which other
 183  * userland processes and threads are spawned.
 184  */
 185 void
 186 mac_cred_label_associate_user(kauth_cred_t cred)
 187 {
 188
 189         MAC_PERFORM(cred_label_associate_user, cred);
 190 }
 191
 192 /*
 193  * When a new process is created, its label must be initialized.  Generally,
 194  * this involves inheritence from the parent process, modulo possible
 195  * deltas.  This function allows that processing to take place.
 196  */
 197 void
 198 mac_cred_label_associate(struct ucred *parent_cred, struct ucred *child_cred)
 199 {
 200
 201         MAC_PERFORM(cred_label_associate, parent_cred, child_cred);
 202 }
 203
 204 int
 205 mac_execve_enter(user_addr_t mac_p, struct image_params *imgp)
 206 {
 207         struct user_mac mac;
 208         struct label *execlabel;
 209         char *buffer;
 210         int error;
 211         size_t ulen;
 212
 213         if (mac_p == USER_ADDR_NULL)
 214                 return (0);
 215
 216         if (IS_64BIT_PROCESS(current_proc())) {
 217                 struct user64_mac mac64;
 218                 error = copyin(mac_p, &mac64, sizeof(mac64));
 219                 mac.m_buflen = mac64.m_buflen;
 220                 mac.m_string = mac64.m_string;
 221         } else {
 222                 struct user32_mac mac32;
 223                 error = copyin(mac_p, &mac32, sizeof(mac32));
 224                 mac.m_buflen = mac32.m_buflen;
 225                 mac.m_string = mac32.m_string;
 226         }
 227         if (error)
 228                 return (error);
 229
 230         error = mac_check_structmac_consistent(&mac);
 231         if (error)
 232                 return (error);
 233
 234         execlabel = mac_cred_label_alloc();
 235         MALLOC(buffer, char *, mac.m_buflen, M_MACTEMP, M_WAITOK);
 236         error = copyinstr(CAST_USER_ADDR_T(mac.m_string), buffer, mac.m_buflen, &ulen);
 237         if (error)
 238                 goto out;
 239         AUDIT_ARG(mac_string, buffer);
 240
 241         error = mac_cred_label_internalize(execlabel, buffer);
 242 out:
 243         if (error) {
 244                 mac_cred_label_free(execlabel);
 245                 execlabel = NULL;
 246         }
 247         imgp->ip_execlabelp = execlabel;
 248         FREE(buffer, M_MACTEMP);
 249         return (error);
 250 }
 251
 252 /*
 253  * When the subject's label changes, it may require revocation of privilege
 254  * to mapped objects.  This can't be done on-the-fly later with a unified
 255  * buffer cache.
 256  *
 257  * XXX:         CRF_MAC_ENFORCE should be in a kauth_cred_t field, rather
 258  * XXX:         than a posix_cred_t field.
 259  */
 260 void
 261 mac_cred_label_update(kauth_cred_t cred, struct label *newlabel)
 262 {
 263         posix_cred_t pcred = posix_cred_get(cred);
 264
 265         /* force label to be part of "matching" for credential */
 266         pcred->cr_flags |= CRF_MAC_ENFORCE;
 267
 268         /* inform the policies of the update */
 269         MAC_PERFORM(cred_label_update, cred, newlabel);
 270 }
 271
 272 int
 273 mac_cred_check_label_update(kauth_cred_t cred, struct label *newlabel)
 274 {
 275         int error;
 276
 277 #if SECURITY_MAC_CHECK_ENFORCE
 278     /* 21167099 - only check if we allow write */
 279     if (!mac_proc_enforce)
 280         return 0;
 281 #endif
 282
 283         MAC_CHECK(cred_check_label_update, cred, newlabel);
 284
 285         return (error);
 286 }
 287
 288 int
 289 mac_cred_check_visible(kauth_cred_t u1, kauth_cred_t u2)
 290 {
 291         int error;
 292
 293 #if SECURITY_MAC_CHECK_ENFORCE
 294     /* 21167099 - only check if we allow write */
 295     if (!mac_proc_enforce)
 296         return 0;
 297 #endif
 298
 299         MAC_CHECK(cred_check_visible, u1, u2);
 300
 301
 302         return (error);
 303 }
 304
 305 /*
 306  * called with process locked.
 307  */
 308 void mac_proc_set_enforce(proc_t p, int enforce_flags)
 309 {
 310         p->p_mac_enforce |= enforce_flags;
 311 }
 312
 313 int
 314 mac_proc_check_debug(proc_t curp, struct proc *proc)
 315 {
 316         kauth_cred_t cred;
 317         int error;
 318
 319 #if SECURITY_MAC_CHECK_ENFORCE
 320     /* 21167099 - only check if we allow write */
 321     if (!mac_proc_enforce)
 322         return 0;
 323 #endif
 324
 325     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 326         return 0;
 327
 328         cred = kauth_cred_proc_ref(curp);
 329         MAC_CHECK(proc_check_debug, cred, proc);
 330         kauth_cred_unref(&cred);
 331
 332         return (error);
 333 }
 334
 335 int
 336 mac_proc_check_fork(proc_t curp)
 337 {
 338         kauth_cred_t cred;
 339         int error;
 340
 341 #if SECURITY_MAC_CHECK_ENFORCE
 342     /* 21167099 - only check if we allow write */
 343     if (!mac_proc_enforce)
 344         return 0;
 345 #endif
 346
 347     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 348         return 0;
 349
 350         cred = kauth_cred_proc_ref(curp);
 351         MAC_CHECK(proc_check_fork, cred, curp);
 352         kauth_cred_unref(&cred);
 353
 354         return (error);
 355 }
 356
 357 int
 358 mac_proc_check_get_task_name(struct ucred *cred, struct proc *p)
 359 {
 360         int error;
 361
 362         MAC_CHECK(proc_check_get_task_name, cred, p);
 363
 364         return (error);
 365 }
 366
 367 int
 368 mac_proc_check_get_task(struct ucred *cred, struct proc *p)
 369 {
 370         int error;
 371
 372         MAC_CHECK(proc_check_get_task, cred, p);
 373
 374         return (error);
 375 }
 376
 377 int
 378 mac_proc_check_expose_task(struct ucred *cred, struct proc *p)
 379 {
 380         int error;
 381
 382         MAC_CHECK(proc_check_expose_task, cred, p);
 383
 384         return (error);
 385 }
 386
 387 int
 388 mac_proc_check_inherit_ipc_ports(struct proc *p, struct vnode *cur_vp, off_t cur_offset, struct vnode *img_vp, off_t img_offset, struct vnode *scriptvp)
 389 {
 390         int error;
 391
 392         MAC_CHECK(proc_check_inherit_ipc_ports, p, cur_vp, cur_offset, img_vp, img_offset, scriptvp);
 393
 394         return (error);
 395 }
 396
 397 /*
 398  * The type of maxprot in proc_check_map_anon must be equivalent to vm_prot_t
 399  * (defined in <mach/vm_prot.h>). mac_policy.h does not include any header
 400  * files, so cannot use the typedef itself.
 401  */
 402 int
 403 mac_proc_check_map_anon(proc_t proc, user_addr_t u_addr,
 404     user_size_t u_size, int prot, int flags, int *maxprot)
 405 {
 406         kauth_cred_t cred;
 407         int error;
 408
 409 #if SECURITY_MAC_CHECK_ENFORCE
 410     /* 21167099 - only check if we allow write */
 411     if (!mac_vm_enforce)
 412         return 0;
 413 #endif
 414         if (!mac_proc_check_enforce(proc, MAC_VM_ENFORCE))
 415                 return (0);
 416
 417         cred = kauth_cred_proc_ref(proc);
 418         MAC_CHECK(proc_check_map_anon, proc, cred, u_addr, u_size, prot, flags, maxprot);
 419         kauth_cred_unref(&cred);
 420
 421         return (error);
 422 }
 423
 424 int
 425 mac_proc_check_mprotect(proc_t proc,
 426     user_addr_t addr, user_size_t size, int prot)
 427 {
 428         kauth_cred_t cred;
 429         int error;
 430
 431 #if SECURITY_MAC_CHECK_ENFORCE
 432     /* 21167099 - only check if we allow write */
 433     if (!mac_vm_enforce)
 434         return 0;
 435 #endif
 436     if (!mac_proc_check_enforce(proc, MAC_VM_ENFORCE))
 437         return (0);
 438
 439         cred = kauth_cred_proc_ref(proc);
 440         MAC_CHECK(proc_check_mprotect, cred, proc, addr, size, prot);
 441         kauth_cred_unref(&cred);
 442
 443         return (error);
 444 }
 445
 446 int
 447 mac_proc_check_run_cs_invalid(proc_t proc)
 448 {
 449         int error;
 450
 451 #if SECURITY_MAC_CHECK_ENFORCE
 452     /* 21167099 - only check if we allow write */
 453     if (!mac_vm_enforce)
 454         return 0;
 455 #endif
 456
 457         MAC_CHECK(proc_check_run_cs_invalid, proc);
 458
 459         return (error);
 460 }
 461
 462 int
 463 mac_proc_check_sched(proc_t curp, struct proc *proc)
 464 {
 465         kauth_cred_t cred;
 466         int error;
 467
 468 #if SECURITY_MAC_CHECK_ENFORCE
 469     /* 21167099 - only check if we allow write */
 470     if (!mac_proc_enforce)
 471         return 0;
 472 #endif
 473
 474     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 475         return 0;
 476
 477         cred = kauth_cred_proc_ref(curp);
 478         MAC_CHECK(proc_check_sched, cred, proc);
 479         kauth_cred_unref(&cred);
 480
 481         return (error);
 482 }
 483
 484 int
 485 mac_proc_check_signal(proc_t curp, struct proc *proc, int signum)
 486 {
 487         kauth_cred_t cred;
 488         int error;
 489
 490 #if SECURITY_MAC_CHECK_ENFORCE
 491     /* 21167099 - only check if we allow write */
 492     if (!mac_proc_enforce)
 493         return 0;
 494 #endif
 495
 496     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 497         return 0;
 498
 499         cred = kauth_cred_proc_ref(curp);
 500         MAC_CHECK(proc_check_signal, cred, proc, signum);
 501         kauth_cred_unref(&cred);
 502
 503         return (error);
 504 }
 505
 506 int
 507 mac_proc_check_wait(proc_t curp, struct proc *proc)
 508 {
 509         kauth_cred_t cred;
 510         int error;
 511
 512 #if SECURITY_MAC_CHECK_ENFORCE
 513     /* 21167099 - only check if we allow write */
 514     if (!mac_proc_enforce)
 515         return 0;
 516 #endif
 517     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 518         return 0;
 519
 520         cred = kauth_cred_proc_ref(curp);
 521         MAC_CHECK(proc_check_wait, cred, proc);
 522         kauth_cred_unref(&cred);
 523
 524         return (error);
 525 }
 526
 527 int
 528 mac_proc_check_suspend_resume(proc_t curp, int sr)
 529 {
 530         kauth_cred_t cred;
 531         int error;
 532
 533 #if SECURITY_MAC_CHECK_ENFORCE
 534     /* 21167099 - only check if we allow write */
 535     if (!mac_proc_enforce)
 536         return 0;
 537 #endif
 538     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 539         return 0;
 540
 541         cred = kauth_cred_proc_ref(curp);
 542         MAC_CHECK(proc_check_suspend_resume, cred, curp, sr);
 543         kauth_cred_unref(&cred);
 544
 545         return (error);
 546 }
 547
 548 int
 549 mac_proc_check_ledger(proc_t curp, proc_t proc, int ledger_op)
 550 {
 551         kauth_cred_t cred;
 552         int error = 0;
 553
 554 #if SECURITY_MAC_CHECK_ENFORCE
 555     /* 21167099 - only check if we allow write */
 556     if (!mac_proc_enforce)
 557         return 0;
 558 #endif
 559     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 560         return 0;
 561
 562         cred = kauth_cred_proc_ref(curp);
 563         MAC_CHECK(proc_check_ledger, cred, proc, ledger_op);
 564         kauth_cred_unref(&cred);
 565
 566         return (error);
 567 }
 568
 569 int
 570 mac_proc_check_cpumon(proc_t curp)
 571 {
 572         kauth_cred_t cred;
 573         int error = 0;
 574
 575 #if SECURITY_MAC_CHECK_ENFORCE
 576     /* 21167099 - only check if we allow write */
 577     if (!mac_proc_enforce)
 578         return 0;
 579 #endif
 580     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 581         return 0;
 582
 583         cred = kauth_cred_proc_ref(curp);
 584         MAC_CHECK(proc_check_cpumon, cred);
 585         kauth_cred_unref(&cred);
 586
 587         return (error);
 588 }
 589
 590 int
 591 mac_proc_check_proc_info(proc_t curp, proc_t target, int callnum, int flavor)
 592 {
 593         kauth_cred_t cred;
 594         int error = 0;
 595
 596 #if SECURITY_MAC_CHECK_ENFORCE
 597     /* 21167099 - only check if we allow write */
 598     if (!mac_proc_enforce)
 599         return 0;
 600 #endif
 601     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 602         return 0;
 603
 604         cred = kauth_cred_proc_ref(curp);
 605         MAC_CHECK(proc_check_proc_info, cred, target, callnum, flavor);
 606         kauth_cred_unref(&cred);
 607
 608         return (error);
 609 }
 610