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