1 /*- 2 * Copyright (c) 1999-2002, 2007-2008 Robert N. M. Watson 3 * Copyright (c) 2001-2005 Networks Associates Technology, Inc. 4 * Copyright (c) 2005 Tom Rhodes 5 * Copyright (c) 2006 SPARTA, Inc. 6 * All rights reserved. 7 * 8 * This software was developed by Robert Watson for the TrustedBSD Project. 9 * It was later enhanced by Tom Rhodes for the TrustedBSD Project. 10 * 11 * This software was developed for the FreeBSD Project in part by Network 12 * Associates Laboratories, the Security Research Division of Network 13 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 14 * as part of the DARPA CHATS research program. 15 * 16 * This software was enhanced by SPARTA ISSO under SPAWAR contract 17 * N66001-04-C-6019 ("SEFOS"). 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 */ 40 41 /* 42 * Developed by the TrustedBSD Project. 43 * 44 * "BSD Extended" MAC policy, allowing the administrator to impose mandatory 45 * firewall-like rules regarding users and file system objects. 46 */ 47 48 #include <sys/param.h> 49 #include <sys/acl.h> 50 #include <sys/kernel.h> 51 #include <sys/jail.h> 52 #include <sys/lock.h> 53 #include <sys/malloc.h> 54 #include <sys/module.h> 55 #include <sys/mount.h> 56 #include <sys/mutex.h> 57 #include <sys/priv.h> 58 #include <sys/proc.h> 59 #include <sys/systm.h> 60 #include <sys/vnode.h> 61 #include <sys/sysctl.h> 62 #include <sys/syslog.h> 63 #include <sys/stat.h> 64 65 #include <security/mac/mac_policy.h> 66 #include <security/mac_bsdextended/mac_bsdextended.h> 67 #include <security/mac_bsdextended/ugidfw_internal.h> 68 69 static struct mtx ugidfw_mtx; 70 71 SYSCTL_DECL(_security_mac); 72 73 static SYSCTL_NODE(_security_mac, OID_AUTO, bsdextended, 74 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 75 "TrustedBSD extended BSD MAC policy controls"); 76 77 static int ugidfw_enabled = 1; 78 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, enabled, CTLFLAG_RWTUN, 79 &ugidfw_enabled, 0, "Enforce extended BSD policy"); 80 81 static MALLOC_DEFINE(M_MACBSDEXTENDED, "mac_bsdextended", 82 "BSD Extended MAC rule"); 83 84 #define MAC_BSDEXTENDED_MAXRULES 250 85 static struct mac_bsdextended_rule *rules[MAC_BSDEXTENDED_MAXRULES]; 86 static int rule_count = 0; 87 static int rule_slots = 0; 88 static int rule_version = MB_VERSION; 89 90 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_count, CTLFLAG_RD, 91 &rule_count, 0, "Number of defined rules\n"); 92 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_slots, CTLFLAG_RD, 93 &rule_slots, 0, "Number of used rule slots\n"); 94 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, rule_version, CTLFLAG_RD, 95 &rule_version, 0, "Version number for API\n"); 96 97 /* 98 * This is just used for logging purposes, eventually we would like to log 99 * much more then failed requests. 100 */ 101 static int ugidfw_logging; 102 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, logging, CTLFLAG_RW, 103 &ugidfw_logging, 0, "Log failed authorization requests"); 104 105 /* 106 * This tunable is here for compatibility. It will allow the user to switch 107 * between the new mode (first rule matches) and the old functionality (all 108 * rules match). 109 */ 110 static int ugidfw_firstmatch_enabled; 111 SYSCTL_INT(_security_mac_bsdextended, OID_AUTO, firstmatch_enabled, 112 CTLFLAG_RW, &ugidfw_firstmatch_enabled, 1, 113 "Disable/enable match first rule functionality"); 114 115 static int 116 ugidfw_rule_valid(struct mac_bsdextended_rule *rule) 117 { 118 119 if ((rule->mbr_subject.mbs_flags | MBS_ALL_FLAGS) != MBS_ALL_FLAGS) 120 return (EINVAL); 121 if ((rule->mbr_subject.mbs_neg | MBS_ALL_FLAGS) != MBS_ALL_FLAGS) 122 return (EINVAL); 123 if ((rule->mbr_object.mbo_flags | MBO_ALL_FLAGS) != MBO_ALL_FLAGS) 124 return (EINVAL); 125 if ((rule->mbr_object.mbo_neg | MBO_ALL_FLAGS) != MBO_ALL_FLAGS) 126 return (EINVAL); 127 if (((rule->mbr_object.mbo_flags & MBO_TYPE_DEFINED) != 0) && 128 (rule->mbr_object.mbo_type | MBO_ALL_TYPE) != MBO_ALL_TYPE) 129 return (EINVAL); 130 if ((rule->mbr_mode | MBI_ALLPERM) != MBI_ALLPERM) 131 return (EINVAL); 132 return (0); 133 } 134 135 static int 136 sysctl_rule(SYSCTL_HANDLER_ARGS) 137 { 138 struct mac_bsdextended_rule temprule, *ruleptr; 139 u_int namelen; 140 int error, index, *name; 141 142 error = 0; 143 name = (int *)arg1; 144 namelen = arg2; 145 if (namelen != 1) 146 return (EINVAL); 147 index = name[0]; 148 if (index >= MAC_BSDEXTENDED_MAXRULES) 149 return (ENOENT); 150 151 ruleptr = NULL; 152 if (req->newptr && req->newlen != 0) { 153 error = SYSCTL_IN(req, &temprule, sizeof(temprule)); 154 if (error) 155 return (error); 156 ruleptr = malloc(sizeof(*ruleptr), M_MACBSDEXTENDED, 157 M_WAITOK | M_ZERO); 158 } 159 160 mtx_lock(&ugidfw_mtx); 161 if (req->oldptr) { 162 if (index < 0 || index > rule_slots + 1) { 163 error = ENOENT; 164 goto out; 165 } 166 if (rules[index] == NULL) { 167 error = ENOENT; 168 goto out; 169 } 170 temprule = *rules[index]; 171 } 172 if (req->newptr && req->newlen == 0) { 173 KASSERT(ruleptr == NULL, ("sysctl_rule: ruleptr != NULL")); 174 ruleptr = rules[index]; 175 if (ruleptr == NULL) { 176 error = ENOENT; 177 goto out; 178 } 179 rule_count--; 180 rules[index] = NULL; 181 } else if (req->newptr) { 182 error = ugidfw_rule_valid(&temprule); 183 if (error) 184 goto out; 185 if (rules[index] == NULL) { 186 *ruleptr = temprule; 187 rules[index] = ruleptr; 188 ruleptr = NULL; 189 if (index + 1 > rule_slots) 190 rule_slots = index + 1; 191 rule_count++; 192 } else 193 *rules[index] = temprule; 194 } 195 out: 196 mtx_unlock(&ugidfw_mtx); 197 if (ruleptr != NULL) 198 free(ruleptr, M_MACBSDEXTENDED); 199 if (req->oldptr && error == 0) 200 error = SYSCTL_OUT(req, &temprule, sizeof(temprule)); 201 return (error); 202 } 203 204 static SYSCTL_NODE(_security_mac_bsdextended, OID_AUTO, rules, 205 CTLFLAG_MPSAFE | CTLFLAG_RW, sysctl_rule, "BSD extended MAC rules"); 206 207 static void 208 ugidfw_init(struct mac_policy_conf *mpc) 209 { 210 211 mtx_init(&ugidfw_mtx, "mac_bsdextended lock", NULL, MTX_DEF); 212 } 213 214 static void 215 ugidfw_destroy(struct mac_policy_conf *mpc) 216 { 217 int i; 218 219 for (i = 0; i < MAC_BSDEXTENDED_MAXRULES; i++) { 220 if (rules[i] != NULL) 221 free(rules[i], M_MACBSDEXTENDED); 222 } 223 mtx_destroy(&ugidfw_mtx); 224 } 225 226 static int 227 ugidfw_rulecheck(struct mac_bsdextended_rule *rule, 228 struct ucred *cred, struct vnode *vp, struct vattr *vap, int acc_mode) 229 { 230 int mac_granted, match, priv_granted; 231 int i; 232 233 /* 234 * Is there a subject match? 235 */ 236 mtx_assert(&ugidfw_mtx, MA_OWNED); 237 if (rule->mbr_subject.mbs_flags & MBS_UID_DEFINED) { 238 match = ((cred->cr_uid <= rule->mbr_subject.mbs_uid_max && 239 cred->cr_uid >= rule->mbr_subject.mbs_uid_min) || 240 (cred->cr_ruid <= rule->mbr_subject.mbs_uid_max && 241 cred->cr_ruid >= rule->mbr_subject.mbs_uid_min) || 242 (cred->cr_svuid <= rule->mbr_subject.mbs_uid_max && 243 cred->cr_svuid >= rule->mbr_subject.mbs_uid_min)); 244 if (rule->mbr_subject.mbs_neg & MBS_UID_DEFINED) 245 match = !match; 246 if (!match) 247 return (0); 248 } 249 250 if (rule->mbr_subject.mbs_flags & MBS_GID_DEFINED) { 251 match = ((cred->cr_rgid <= rule->mbr_subject.mbs_gid_max && 252 cred->cr_rgid >= rule->mbr_subject.mbs_gid_min) || 253 (cred->cr_svgid <= rule->mbr_subject.mbs_gid_max && 254 cred->cr_svgid >= rule->mbr_subject.mbs_gid_min)); 255 if (!match) { 256 for (i = 0; i < cred->cr_ngroups; i++) { 257 if (cred->cr_groups[i] 258 <= rule->mbr_subject.mbs_gid_max && 259 cred->cr_groups[i] 260 >= rule->mbr_subject.mbs_gid_min) { 261 match = 1; 262 break; 263 } 264 } 265 } 266 if (rule->mbr_subject.mbs_neg & MBS_GID_DEFINED) 267 match = !match; 268 if (!match) 269 return (0); 270 } 271 272 if (rule->mbr_subject.mbs_flags & MBS_PRISON_DEFINED) { 273 match = 274 (cred->cr_prison->pr_id == rule->mbr_subject.mbs_prison); 275 if (rule->mbr_subject.mbs_neg & MBS_PRISON_DEFINED) 276 match = !match; 277 if (!match) 278 return (0); 279 } 280 281 /* 282 * Is there an object match? 283 */ 284 if (rule->mbr_object.mbo_flags & MBO_UID_DEFINED) { 285 match = (vap->va_uid <= rule->mbr_object.mbo_uid_max && 286 vap->va_uid >= rule->mbr_object.mbo_uid_min); 287 if (rule->mbr_object.mbo_neg & MBO_UID_DEFINED) 288 match = !match; 289 if (!match) 290 return (0); 291 } 292 293 if (rule->mbr_object.mbo_flags & MBO_GID_DEFINED) { 294 match = (vap->va_gid <= rule->mbr_object.mbo_gid_max && 295 vap->va_gid >= rule->mbr_object.mbo_gid_min); 296 if (rule->mbr_object.mbo_neg & MBO_GID_DEFINED) 297 match = !match; 298 if (!match) 299 return (0); 300 } 301 302 if (rule->mbr_object.mbo_flags & MBO_FSID_DEFINED) { 303 match = (fsidcmp(&vp->v_mount->mnt_stat.f_fsid, 304 &rule->mbr_object.mbo_fsid) == 0); 305 if (rule->mbr_object.mbo_neg & MBO_FSID_DEFINED) 306 match = !match; 307 if (!match) 308 return (0); 309 } 310 311 if (rule->mbr_object.mbo_flags & MBO_SUID) { 312 match = (vap->va_mode & S_ISUID); 313 if (rule->mbr_object.mbo_neg & MBO_SUID) 314 match = !match; 315 if (!match) 316 return (0); 317 } 318 319 if (rule->mbr_object.mbo_flags & MBO_SGID) { 320 match = (vap->va_mode & S_ISGID); 321 if (rule->mbr_object.mbo_neg & MBO_SGID) 322 match = !match; 323 if (!match) 324 return (0); 325 } 326 327 if (rule->mbr_object.mbo_flags & MBO_UID_SUBJECT) { 328 match = (vap->va_uid == cred->cr_uid || 329 vap->va_uid == cred->cr_ruid || 330 vap->va_uid == cred->cr_svuid); 331 if (rule->mbr_object.mbo_neg & MBO_UID_SUBJECT) 332 match = !match; 333 if (!match) 334 return (0); 335 } 336 337 if (rule->mbr_object.mbo_flags & MBO_GID_SUBJECT) { 338 match = (groupmember(vap->va_gid, cred) || 339 vap->va_gid == cred->cr_rgid || 340 vap->va_gid == cred->cr_svgid); 341 if (rule->mbr_object.mbo_neg & MBO_GID_SUBJECT) 342 match = !match; 343 if (!match) 344 return (0); 345 } 346 347 if (rule->mbr_object.mbo_flags & MBO_TYPE_DEFINED) { 348 switch (vap->va_type) { 349 case VREG: 350 match = (rule->mbr_object.mbo_type & MBO_TYPE_REG); 351 break; 352 case VDIR: 353 match = (rule->mbr_object.mbo_type & MBO_TYPE_DIR); 354 break; 355 case VBLK: 356 match = (rule->mbr_object.mbo_type & MBO_TYPE_BLK); 357 break; 358 case VCHR: 359 match = (rule->mbr_object.mbo_type & MBO_TYPE_CHR); 360 break; 361 case VLNK: 362 match = (rule->mbr_object.mbo_type & MBO_TYPE_LNK); 363 break; 364 case VSOCK: 365 match = (rule->mbr_object.mbo_type & MBO_TYPE_SOCK); 366 break; 367 case VFIFO: 368 match = (rule->mbr_object.mbo_type & MBO_TYPE_FIFO); 369 break; 370 default: 371 match = 0; 372 } 373 if (rule->mbr_object.mbo_neg & MBO_TYPE_DEFINED) 374 match = !match; 375 if (!match) 376 return (0); 377 } 378 379 /* 380 * MBI_APPEND should not be here as it should get converted to 381 * MBI_WRITE. 382 */ 383 priv_granted = 0; 384 mac_granted = rule->mbr_mode; 385 if ((acc_mode & MBI_ADMIN) && (mac_granted & MBI_ADMIN) == 0 && 386 priv_check_cred(cred, PRIV_VFS_ADMIN) == 0) 387 priv_granted |= MBI_ADMIN; 388 if ((acc_mode & MBI_EXEC) && (mac_granted & MBI_EXEC) == 0 && 389 priv_check_cred(cred, (vap->va_type == VDIR) ? PRIV_VFS_LOOKUP : PRIV_VFS_EXEC) == 0) 390 priv_granted |= MBI_EXEC; 391 if ((acc_mode & MBI_READ) && (mac_granted & MBI_READ) == 0 && 392 priv_check_cred(cred, PRIV_VFS_READ) == 0) 393 priv_granted |= MBI_READ; 394 if ((acc_mode & MBI_STAT) && (mac_granted & MBI_STAT) == 0 && 395 priv_check_cred(cred, PRIV_VFS_STAT) == 0) 396 priv_granted |= MBI_STAT; 397 if ((acc_mode & MBI_WRITE) && (mac_granted & MBI_WRITE) == 0 && 398 priv_check_cred(cred, PRIV_VFS_WRITE) == 0) 399 priv_granted |= MBI_WRITE; 400 /* 401 * Is the access permitted? 402 */ 403 if (((mac_granted | priv_granted) & acc_mode) != acc_mode) { 404 if (ugidfw_logging) 405 log(LOG_AUTHPRIV, "mac_bsdextended: %d:%d request %d" 406 " on %d:%d failed. \n", cred->cr_ruid, 407 cred->cr_rgid, acc_mode, vap->va_uid, 408 vap->va_gid); 409 return (EACCES); 410 } 411 412 /* 413 * If the rule matched, permits access, and first match is enabled, 414 * return success. 415 */ 416 if (ugidfw_firstmatch_enabled) 417 return (EJUSTRETURN); 418 else 419 return (0); 420 } 421 422 int 423 ugidfw_check(struct ucred *cred, struct vnode *vp, struct vattr *vap, 424 int acc_mode) 425 { 426 int error, i; 427 428 /* 429 * Since we do not separately handle append, map append to write. 430 */ 431 if (acc_mode & MBI_APPEND) { 432 acc_mode &= ~MBI_APPEND; 433 acc_mode |= MBI_WRITE; 434 } 435 mtx_lock(&ugidfw_mtx); 436 for (i = 0; i < rule_slots; i++) { 437 if (rules[i] == NULL) 438 continue; 439 error = ugidfw_rulecheck(rules[i], cred, 440 vp, vap, acc_mode); 441 if (error == EJUSTRETURN) 442 break; 443 if (error) { 444 mtx_unlock(&ugidfw_mtx); 445 return (error); 446 } 447 } 448 mtx_unlock(&ugidfw_mtx); 449 return (0); 450 } 451 452 int 453 ugidfw_check_vp(struct ucred *cred, struct vnode *vp, int acc_mode) 454 { 455 int error; 456 struct vattr vap; 457 458 if (!ugidfw_enabled) 459 return (0); 460 error = VOP_GETATTR(vp, &vap, cred); 461 if (error) 462 return (error); 463 return (ugidfw_check(cred, vp, &vap, acc_mode)); 464 } 465 466 int 467 ugidfw_accmode2mbi(accmode_t accmode) 468 { 469 int mbi; 470 471 mbi = 0; 472 if (accmode & VEXEC) 473 mbi |= MBI_EXEC; 474 if (accmode & VWRITE) 475 mbi |= MBI_WRITE; 476 if (accmode & VREAD) 477 mbi |= MBI_READ; 478 if (accmode & VADMIN_PERMS) 479 mbi |= MBI_ADMIN; 480 if (accmode & VSTAT_PERMS) 481 mbi |= MBI_STAT; 482 if (accmode & VAPPEND) 483 mbi |= MBI_APPEND; 484 return (mbi); 485 } 486 487 static struct mac_policy_ops ugidfw_ops = 488 { 489 .mpo_destroy = ugidfw_destroy, 490 .mpo_init = ugidfw_init, 491 .mpo_system_check_acct = ugidfw_system_check_acct, 492 .mpo_system_check_auditctl = ugidfw_system_check_auditctl, 493 .mpo_system_check_swapon = ugidfw_system_check_swapon, 494 .mpo_vnode_check_access = ugidfw_vnode_check_access, 495 .mpo_vnode_check_chdir = ugidfw_vnode_check_chdir, 496 .mpo_vnode_check_chroot = ugidfw_vnode_check_chroot, 497 .mpo_vnode_check_create = ugidfw_check_create_vnode, 498 .mpo_vnode_check_deleteacl = ugidfw_vnode_check_deleteacl, 499 .mpo_vnode_check_deleteextattr = ugidfw_vnode_check_deleteextattr, 500 .mpo_vnode_check_exec = ugidfw_vnode_check_exec, 501 .mpo_vnode_check_getacl = ugidfw_vnode_check_getacl, 502 .mpo_vnode_check_getextattr = ugidfw_vnode_check_getextattr, 503 .mpo_vnode_check_link = ugidfw_vnode_check_link, 504 .mpo_vnode_check_listextattr = ugidfw_vnode_check_listextattr, 505 .mpo_vnode_check_lookup = ugidfw_vnode_check_lookup, 506 .mpo_vnode_check_open = ugidfw_vnode_check_open, 507 .mpo_vnode_check_readdir = ugidfw_vnode_check_readdir, 508 .mpo_vnode_check_readlink = ugidfw_vnode_check_readdlink, 509 .mpo_vnode_check_rename_from = ugidfw_vnode_check_rename_from, 510 .mpo_vnode_check_rename_to = ugidfw_vnode_check_rename_to, 511 .mpo_vnode_check_revoke = ugidfw_vnode_check_revoke, 512 .mpo_vnode_check_setacl = ugidfw_check_setacl_vnode, 513 .mpo_vnode_check_setextattr = ugidfw_vnode_check_setextattr, 514 .mpo_vnode_check_setflags = ugidfw_vnode_check_setflags, 515 .mpo_vnode_check_setmode = ugidfw_vnode_check_setmode, 516 .mpo_vnode_check_setowner = ugidfw_vnode_check_setowner, 517 .mpo_vnode_check_setutimes = ugidfw_vnode_check_setutimes, 518 .mpo_vnode_check_stat = ugidfw_vnode_check_stat, 519 .mpo_vnode_check_unlink = ugidfw_vnode_check_unlink, 520 }; 521 522 MAC_POLICY_SET(&ugidfw_ops, mac_bsdextended, "TrustedBSD MAC/BSD Extended", 523 MPC_LOADTIME_FLAG_UNLOADOK, NULL); 524