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 #if CONFIG_AUDIT
  78
  79 /* The zone allocator is initialized in mac_base.c. */
  80 zone_t mac_audit_data_zone;
  81
  82 int
  83 mac_system_check_audit(struct ucred *cred, void *record, int length)
  84 {
  85         int error;
  86
  87         MAC_CHECK(system_check_audit, cred, record, length);
  88
  89         return (error);
  90 }
  91
  92 int
  93 mac_system_check_auditon(struct ucred *cred, int cmd)
  94 {
  95         int error;
  96
  97         MAC_CHECK(system_check_auditon, cred, cmd);
  98
  99         return (error);
 100 }
 101
 102 int
 103 mac_system_check_auditctl(struct ucred *cred, struct vnode *vp)
 104 {
 105         int error;
 106         struct label *vl = vp ? vp->v_label : NULL;
 107
 108         MAC_CHECK(system_check_auditctl, cred, vp, vl);
 109
 110         return (error);
 111 }
 112
 113 int
 114 mac_proc_check_getauid(struct proc *curp)
 115 {
 116         kauth_cred_t cred;
 117         int error;
 118
 119 #if SECURITY_MAC_CHECK_ENFORCE
 120     /* 21167099 - only check if we allow write */
 121     if (!mac_proc_enforce)
 122         return 0;
 123 #endif
 124
 125         if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 126                 return 0;
 127
 128         cred = kauth_cred_proc_ref(curp);
 129         MAC_CHECK(proc_check_getauid, cred);
 130         kauth_cred_unref(&cred);
 131
 132         return (error);
 133 }
 134
 135 int
 136 mac_proc_check_setauid(struct proc *curp, uid_t auid)
 137 {
 138         kauth_cred_t cred;
 139         int error;
 140
 141 #if SECURITY_MAC_CHECK_ENFORCE
 142     /* 21167099 - only check if we allow write */
 143     if (!mac_proc_enforce)
 144         return 0;
 145 #endif
 146     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 147         return 0;
 148
 149         cred = kauth_cred_proc_ref(curp);
 150         MAC_CHECK(proc_check_setauid, cred, auid);
 151         kauth_cred_unref(&cred);
 152
 153         return (error);
 154 }
 155
 156 int
 157 mac_proc_check_getaudit(struct proc *curp)
 158 {
 159         kauth_cred_t cred;
 160         int error;
 161
 162 #if SECURITY_MAC_CHECK_ENFORCE
 163     /* 21167099 - only check if we allow write */
 164     if (!mac_proc_enforce)
 165         return 0;
 166 #endif
 167     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 168         return 0;
 169
 170         cred = kauth_cred_proc_ref(curp);
 171         MAC_CHECK(proc_check_getaudit, cred);
 172         kauth_cred_unref(&cred);
 173
 174         return (error);
 175 }
 176
 177 int
 178 mac_proc_check_setaudit(struct proc *curp, struct auditinfo_addr *ai)
 179 {
 180         kauth_cred_t cred;
 181         int error;
 182
 183 #if SECURITY_MAC_CHECK_ENFORCE
 184     /* 21167099 - only check if we allow write */
 185     if (!mac_proc_enforce)
 186         return 0;
 187 #endif
 188     if (!mac_proc_check_enforce(curp, MAC_PROC_ENFORCE))
 189         return 0;
 190
 191         cred = kauth_cred_proc_ref(curp);
 192         MAC_CHECK(proc_check_setaudit, cred, ai);
 193         kauth_cred_unref(&cred);
 194
 195         return (error);
 196 }
 197
 198 #if 0
 199 /*
 200  * This is the framework entry point for MAC policies to use to add
 201  * arbitrary data to the current audit record.
 202  * (Currently not supported, as no existing audit viewers would
 203  * display this format)
 204  *
 205  */
 206 int
 207 mac_audit_data(int len, u_char *data, mac_policy_handle_t handle)
 208 {
 209         char *sanitized;
 210
 211         if ((len <= 0) || (len > MAC_AUDIT_DATA_LIMIT))
 212                 return (EINVAL);
 213
 214         sanitized = (char *)zalloc(mac_audit_data_zone);
 215
 216         bcopy(data, sanitized, len);
 217         return (audit_mac_data(MAC_AUDIT_DATA_TYPE, len, sanitized));
 218 }
 219 #endif
 220
 221 /*
 222  * This is the entry point a MAC policy will call to add NULL-
 223  * terminated ASCII text to the current audit record.
 224  */
 225 int
 226 mac_audit_text(char *text, mac_policy_handle_t handle)
 227 {
 228         char *sanitized;
 229         const char *name;
 230         int i, size, plen, len;
 231
 232         name = mac_get_mpc(handle)->mpc_name;
 233         len = strlen(text);
 234         plen = 2 + strlen(name);
 235         if (plen + len >= MAC_AUDIT_DATA_LIMIT)
 236                 return (EINVAL);
 237
 238         /*
 239          * Make sure the text is only composed of only ASCII printable
 240          * characters.
 241          */
 242         for (i=0; i < len; i++)
 243                 if (text[i] < (char) 32 || text[i] > (char) 126)
 244                         return (EINVAL);
 245
 246         size = len + plen + 1;
 247         sanitized = (char *)zalloc(mac_audit_data_zone);
 248
 249         strlcpy(sanitized, name, MAC_AUDIT_DATA_LIMIT);
 250         strncat(sanitized, ": ", MAC_AUDIT_DATA_LIMIT - plen + 2);
 251         strncat(sanitized, text, MAC_AUDIT_DATA_LIMIT - plen);
 252
 253         return (audit_mac_data(MAC_AUDIT_TEXT_TYPE, size, (u_char *)sanitized));
 254 }
 255
 256 int
 257 mac_audit_check_preselect(struct ucred *cred, unsigned short syscode, void *args)
 258 {
 259         struct mac_policy_conf *mpc;
 260         int ret, error;
 261         u_int i;
 262
 263         ret = MAC_AUDIT_DEFAULT;
 264         for (i = 0; i < mac_policy_list.staticmax; i++) {
 265                 mpc = mac_policy_list.entries[i].mpc;
 266                 if (mpc == NULL)
 267                         continue;
 268
 269                 if (mpc->mpc_ops->mpo_audit_check_preselect != NULL) {
 270                         error = mpc->mpc_ops->mpo_audit_check_preselect(cred,
 271                             syscode, args);
 272                         ret = (ret > error ? ret : error);
 273                 }
 274         }
 275         if (mac_policy_list_conditional_busy() != 0) {
 276                 for (; i <= mac_policy_list.maxindex; i++) {
 277                         mpc = mac_policy_list.entries[i].mpc;
 278                         if (mpc == NULL)
 279                                 continue;
 280
 281                         if (mpc->mpc_ops->mpo_audit_check_preselect != NULL) {
 282                                 error = mpc->mpc_ops->mpo_audit_check_preselect(cred,
 283                                     syscode, args);
 284                                 ret = (ret > error ? ret : error);
 285                         }
 286                 }
 287                 mac_policy_list_unbusy();
 288         }
 289
 290         return (ret);
 291 }
 292
 293 int
 294 mac_audit_check_postselect(struct ucred *cred, unsigned short syscode,
 295     void *args, int error, int retval, int mac_forced)
 296 {
 297         struct mac_policy_conf *mpc;
 298         int ret, mac_error;
 299         u_int i;
 300
 301         /*
 302          * If the audit was forced by a MAC policy by mac_audit_check_preselect(),
 303          * echo that.
 304          */
 305         if (mac_forced)
 306                 return (MAC_AUDIT_YES);
 307
 308         ret = MAC_AUDIT_DEFAULT;
 309         for (i = 0; i < mac_policy_list.staticmax; i++) {
 310                 mpc = mac_policy_list.entries[i].mpc;
 311                 if (mpc == NULL)
 312                         continue;
 313
 314                 if (mpc->mpc_ops->mpo_audit_check_postselect != NULL) {
 315                         mac_error = mpc->mpc_ops->mpo_audit_check_postselect(cred,
 316                             syscode, args, error, retval);
 317                         ret = (ret > mac_error ? ret : mac_error);
 318                 }
 319         }
 320         if (mac_policy_list_conditional_busy() != 0) {
 321                 for (; i <= mac_policy_list.maxindex; i++) {
 322                         mpc = mac_policy_list.entries[i].mpc;
 323                         if (mpc == NULL)
 324                                 continue;
 325
 326                         if (mpc->mpc_ops->mpo_audit_check_postselect != NULL) {
 327                                 mac_error = mpc->mpc_ops->mpo_audit_check_postselect(cred,
 328                                     syscode, args, error, retval);
 329                                 ret = (ret > mac_error ? ret : mac_error);
 330                         }
 331                 }
 332                 mac_policy_list_unbusy();
 333         }
 334
 335         return (ret);
 336 }
 337
 338 #else   /* !CONFIG_AUDIT */
 339
 340 /*
 341  * Function stubs for when AUDIT isn't defined.
 342  */
 343
 344 int
 345 mac_system_check_audit(__unused struct ucred *cred, __unused void *record, __unused int length)
 346 {
 347
 348         return (0);
 349 }
 350
 351 int
 352 mac_system_check_auditon(__unused struct ucred *cred, __unused int cmd)
 353 {
 354
 355         return (0);
 356 }
 357
 358 int
 359 mac_system_check_auditctl(__unused struct ucred *cred, __unused struct vnode *vp)
 360 {
 361
 362         return (0);
 363 }
 364
 365 int
 366 mac_proc_check_getauid(__unused struct proc *curp)
 367 {
 368
 369         return (0);
 370 }
 371
 372 int
 373 mac_proc_check_setauid(__unused struct proc *curp, __unused uid_t auid)
 374 {
 375
 376         return (0);
 377 }
 378
 379 int
 380 mac_proc_check_getaudit(__unused struct proc *curp)
 381 {
 382
 383         return (0);
 384 }
 385
 386 int
 387 mac_proc_check_setaudit(__unused struct proc *curp,
 388     __unused struct auditinfo_addr *ai)
 389 {
 390
 391         return (0);
 392 }
 393
 394 int
 395 mac_audit_check_preselect(__unused struct ucred *cred, __unused unsigned short syscode,
 396     __unused void *args)
 397 {
 398
 399         return (MAC_AUDIT_DEFAULT);
 400 }
 401
 402 int
 403 mac_audit_check_postselect(__unused struct ucred *cred, __unused unsigned short syscode,
 404     __unused void *args, __unused int error, __unused int retval, __unused int mac_forced)
 405 {
 406
 407         return (MAC_AUDIT_DEFAULT);
 408 }
 409
 410 int
 411 mac_audit_text(__unused char *text, __unused mac_policy_handle_t handle)
 412 {
 413         return (0);
 414 }
 415 #endif  /* !CONFIG_AUDIT */