security/mac_audit.c

   1 /*
   2  * Copyright (c) 2006-2007 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  * Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
  30  * Copyright (c) 2001 Ilmar S. Habibulin
  31  * Copyright (c) 2001, 2002, 2003, 2004 Networks Associates Technology, Inc.
  32  *
  33  * This software was developed by Robert Watson and Ilmar Habibulin for the
  34  * TrustedBSD Project.
  35  *
  36  * This software was developed for the FreeBSD Project in part by Network
  37  * Associates Laboratories, the Security Research Division of Network
  38  * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
  39  * as part of the DARPA CHATS research program.
  40  *
  41  * Redistribution and use in source and binary forms, with or without
  42  * modification, are permitted provided that the following conditions
  43  * are met:
  44  * 1. Redistributions of source code must retain the above copyright
  45  *    notice, this list of conditions and the following disclaimer.
  46  * 2. Redistributions in binary form must reproduce the above copyright
  47  *    notice, this list of conditions and the following disclaimer in the
  48  *    documentation and/or other materials provided with the distribution.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  *
  62  */
  63 #include <sys/param.h>
  64 #include <sys/types.h>
  65 #include <sys/vnode.h>
  66 #include <sys/vnode_internal.h>
  67 #include <sys/kauth.h>
  68 #include <sys/queue.h>
  69 #include <security/mac_internal.h>
  70 #include <bsd/bsm/audit.h>
  71 #include <bsd/security/audit/audit.h>
  72 #include <bsd/sys/malloc.h>
  73 #include <vm/vm_kern.h>
  74 #include <kern/kalloc.h>
  75 #include <kern/zalloc.h>
  76
  77
  78 int mac_audit(__unused int len, __unused u_char *data);
  79
  80
  81 #if CONFIG_AUDIT
  82
  83 /* The zone allocator is initialized in mac_base.c. */
  84 zone_t mac_audit_data_zone;
  85
  86 int
  87 mac_system_check_audit(struct ucred *cred, void *record, int length)
  88 {
  89         int error;
  90
  91         MAC_CHECK(system_check_audit, cred, record, length);
  92
  93         return (error);
  94 }
  95
  96 int
  97 mac_system_check_auditon(struct ucred *cred, int cmd)
  98 {
  99         int error;
 100
 101         MAC_CHECK(system_check_auditon, cred, cmd);
 102
 103         return (error);
 104 }
 105
 106 int
 107 mac_system_check_auditctl(struct ucred *cred, struct vnode *vp)
 108 {
 109         int error;
 110         struct label *vl = vp ? vp->v_label : NULL;
 111
 112         MAC_CHECK(system_check_auditctl, cred, vp, vl);
 113
 114         return (error);
 115 }
 116
 117 int
 118 mac_proc_check_getauid(struct proc *curp)
 119 {
 120         kauth_cred_t cred;
 121         int error;
 122
 123         if (!mac_proc_enforce ||
 124             !mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 125                 return 0;
 126
 127         cred = kauth_cred_proc_ref(curp);
 128         MAC_CHECK(proc_check_getauid, cred);
 129         kauth_cred_unref(&cred);
 130
 131         return (error);
 132 }
 133
 134 int
 135 mac_proc_check_setauid(struct proc *curp, uid_t auid)
 136 {
 137         kauth_cred_t cred;
 138         int error;
 139
 140         if (!mac_proc_enforce ||
 141             !mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 142                 return 0;
 143
 144         cred = kauth_cred_proc_ref(curp);
 145         MAC_CHECK(proc_check_setauid, cred, auid);
 146         kauth_cred_unref(&cred);
 147
 148         return (error);
 149 }
 150
 151 int
 152 mac_proc_check_getaudit(struct proc *curp)
 153 {
 154         kauth_cred_t cred;
 155         int error;
 156
 157         if (!mac_proc_enforce ||
 158             !mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 159                 return 0;
 160
 161         cred = kauth_cred_proc_ref(curp);
 162         MAC_CHECK(proc_check_getaudit, cred);
 163         kauth_cred_unref(&cred);
 164
 165         return (error);
 166 }
 167
 168 int
 169 mac_proc_check_setaudit(struct proc *curp, struct auditinfo_addr *ai)
 170 {
 171         kauth_cred_t cred;
 172         int error;
 173
 174         if (!mac_proc_enforce ||
 175             !mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 176                 return 0;
 177
 178         cred = kauth_cred_proc_ref(curp);
 179         MAC_CHECK(proc_check_setaudit, cred, ai);
 180         kauth_cred_unref(&cred);
 181
 182         return (error);
 183 }
 184
 185 #if 0
 186 /*
 187  * This is the framework entry point for MAC policies to use to add
 188  * arbitrary data to the current audit record.
 189  * (Currently not supported, as no existing audit viewers would
 190  * display this format)
 191  *
 192  */
 193 int
 194 mac_audit_data(int len, u_char *data, mac_policy_handle_t handle)
 195 {
 196         char *sanitized;
 197
 198         if ((len <= 0) || (len > MAC_AUDIT_DATA_LIMIT))
 199                 return (EINVAL);
 200
 201         sanitized = (char *)zalloc(mac_audit_data_zone);
 202
 203         bcopy(data, sanitized, len);
 204         return (audit_mac_data(MAC_AUDIT_DATA_TYPE, len, sanitized));
 205 }
 206 #endif
 207
 208 /*
 209  * This is the entry point a MAC policy will call to add NULL-
 210  * terminated ASCII text to the current audit record.
 211  */
 212 int
 213 mac_audit_text(char *text, mac_policy_handle_t handle)
 214 {
 215         char *sanitized;
 216         const char *name;
 217         int i, size, plen, len;
 218
 219         name = mac_get_mpc(handle)->mpc_name;
 220         len = strlen(text);
 221         plen = 2 + strlen(name);
 222         if (plen + len >= MAC_AUDIT_DATA_LIMIT)
 223                 return (EINVAL);
 224
 225         /*
 226          * Make sure the text is only composed of only ASCII printable
 227          * characters.
 228          */
 229         for (i=0; i < len; i++)
 230                 if (text[i] < (char) 32 || text[i] > (char) 126)
 231                         return (EINVAL);
 232
 233         size = len + plen + 1;
 234         sanitized = (char *)zalloc(mac_audit_data_zone);
 235
 236         strlcpy(sanitized, name, MAC_AUDIT_DATA_LIMIT);
 237         strncat(sanitized, ": ", MAC_AUDIT_DATA_LIMIT - plen + 2);
 238         strncat(sanitized, text, MAC_AUDIT_DATA_LIMIT - plen);
 239
 240         return (audit_mac_data(MAC_AUDIT_TEXT_TYPE, size, (u_char *)sanitized));
 241 }
 242
 243 int
 244 mac_audit_check_preselect(struct ucred *cred, unsigned short syscode, void *args)
 245 {
 246         struct mac_policy_conf *mpc;
 247         int ret, error;
 248         u_int i;
 249
 250         ret = MAC_AUDIT_DEFAULT;
 251         for (i = 0; i < mac_policy_list.staticmax; i++) {
 252                 mpc = mac_policy_list.entries[i].mpc;
 253                 if (mpc == NULL)
 254                         continue;
 255
 256                 if (mpc->mpc_ops->mpo_audit_check_preselect != NULL) {
 257                         error = mpc->mpc_ops->mpo_audit_check_preselect(cred,
 258                             syscode, args);
 259                         ret = (ret > error ? ret : error);
 260                 }
 261         }
 262         if (mac_policy_list_conditional_busy() != 0) {
 263                 for (; i <= mac_policy_list.maxindex; i++) {
 264                         mpc = mac_policy_list.entries[i].mpc;
 265                         if (mpc == NULL)
 266                                 continue;
 267
 268                         if (mpc->mpc_ops->mpo_audit_check_preselect != NULL) {
 269                                 error = mpc->mpc_ops->mpo_audit_check_preselect(cred,
 270                                     syscode, args);
 271                                 ret = (ret > error ? ret : error);
 272                         }
 273                 }
 274                 mac_policy_list_unbusy();
 275         }
 276
 277         return (ret);
 278 }
 279
 280 int
 281 mac_audit_check_postselect(struct ucred *cred, unsigned short syscode,
 282     void *args, int error, int retval, int mac_forced)
 283 {
 284         struct mac_policy_conf *mpc;
 285         int ret, mac_error;
 286         u_int i;
 287
 288         /*
 289          * If the audit was forced by a MAC policy by mac_audit_check_preselect(),
 290          * echo that.
 291          */
 292         if (mac_forced)
 293                 return (MAC_AUDIT_YES);
 294
 295         ret = MAC_AUDIT_DEFAULT;
 296         for (i = 0; i < mac_policy_list.staticmax; i++) {
 297                 mpc = mac_policy_list.entries[i].mpc;
 298                 if (mpc == NULL)
 299                         continue;
 300
 301                 if (mpc->mpc_ops->mpo_audit_check_postselect != NULL) {
 302                         mac_error = mpc->mpc_ops->mpo_audit_check_postselect(cred,
 303                             syscode, args, error, retval);
 304                         ret = (ret > mac_error ? ret : mac_error);
 305                 }
 306         }
 307         if (mac_policy_list_conditional_busy() != 0) {
 308                 for (; i <= mac_policy_list.maxindex; i++) {
 309                         mpc = mac_policy_list.entries[i].mpc;
 310                         if (mpc == NULL)
 311                                 continue;
 312
 313                         if (mpc->mpc_ops->mpo_audit_check_postselect != NULL) {
 314                                 mac_error = mpc->mpc_ops->mpo_audit_check_postselect(cred,
 315                                     syscode, args, error, retval);
 316                                 ret = (ret > mac_error ? ret : mac_error);
 317                         }
 318                 }
 319                 mac_policy_list_unbusy();
 320         }
 321
 322         return (ret);
 323 }
 324
 325 #else   /* !CONFIG_AUDIT */
 326
 327 /*
 328  * Function stubs for when AUDIT isn't defined.
 329  */
 330
 331 int
 332 mac_system_check_audit(__unused struct ucred *cred, __unused void *record, __unused int length)
 333 {
 334
 335         return (0);
 336 }
 337
 338 int
 339 mac_system_check_auditon(__unused struct ucred *cred, __unused int cmd)
 340 {
 341
 342         return (0);
 343 }
 344
 345 int
 346 mac_system_check_auditctl(__unused struct ucred *cred, __unused struct vnode *vp)
 347 {
 348
 349         return (0);
 350 }
 351
 352 int
 353 mac_proc_check_getauid(__unused struct proc *curp)
 354 {
 355
 356         return (0);
 357 }
 358
 359 int
 360 mac_proc_check_setauid(__unused struct proc *curp, __unused uid_t auid)
 361 {
 362
 363         return (0);
 364 }
 365
 366 int
 367 mac_proc_check_getaudit(__unused struct proc *curp)
 368 {
 369
 370         return (0);
 371 }
 372
 373 int
 374 mac_proc_check_setaudit(__unused struct proc *curp,
 375     __unused struct auditinfo_addr *ai)
 376 {
 377
 378         return (0);
 379 }
 380
 381 int
 382 mac_audit_check_preselect(__unused struct ucred *cred, __unused unsigned short syscode,
 383     __unused void *args)
 384 {
 385
 386         return (MAC_AUDIT_DEFAULT);
 387 }
 388
 389 int
 390 mac_audit_check_postselect(__unused struct ucred *cred, __unused unsigned short syscode,
 391     __unused void *args, __unused int error, __unused int retval, __unused int mac_forced)
 392 {
 393
 394         return (MAC_AUDIT_DEFAULT);
 395 }
 396
 397 int
 398 mac_audit(__unused int len, __unused u_char *data)
 399 {
 400
 401         return (0);
 402 }
 403
 404 int
 405 mac_audit_text(__unused char *text, __unused mac_policy_handle_t handle)
 406 {
 407         return (0);
 408 }
 409 #endif  /* !CONFIG_AUDIT */