secmodel_securelevel.c revision 1.2
1 /* $NetBSD: secmodel_securelevel.c,v 1.2 2007/11/24 20:47:14 elad Exp $ */ 2 /*- 3 * Copyright (c) 2006 Elad Efrat <elad (at) NetBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * This file contains kauth(9) listeners needed to implement the traditional 31 * NetBSD securelevel. 32 * 33 * The securelevel is a system-global indication on what operations are 34 * allowed or not. It affects all users, including root. 35 */ 36 37 #include <sys/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: secmodel_securelevel.c,v 1.2 2007/11/24 20:47:14 elad Exp $"); 39 40 #ifdef _KERNEL_OPT 41 #include "opt_insecure.h" 42 #endif /* _KERNEL_OPT */ 43 44 #include <sys/types.h> 45 #include <sys/param.h> 46 #include <sys/kauth.h> 47 48 #include <sys/conf.h> 49 #include <sys/mount.h> 50 #include <sys/sysctl.h> 51 #include <sys/vnode.h> 52 53 #include <miscfs/specfs/specdev.h> 54 55 #include <secmodel/securelevel/securelevel.h> 56 57 static int securelevel; 58 59 static kauth_listener_t l_system, l_process, l_network, l_machdep, l_device; 60 61 /* 62 * sysctl helper routine for securelevel. ensures that the value 63 * only rises unless the caller has pid 1 (assumed to be init). 64 */ 65 int 66 secmodel_securelevel_sysctl(SYSCTLFN_ARGS) 67 { 68 int newsecurelevel, error; 69 struct sysctlnode node; 70 71 newsecurelevel = securelevel; 72 node = *rnode; 73 node.sysctl_data = &newsecurelevel; 74 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 75 if (error || newp == NULL) 76 return (error); 77 78 if (newsecurelevel < securelevel && l && l->l_proc->p_pid != 1) 79 return (EPERM); 80 81 securelevel = newsecurelevel; 82 83 return (error); 84 } 85 86 void 87 secmodel_securelevel_init(void) 88 { 89 #ifdef INSECURE 90 securelevel = -1; 91 #else 92 securelevel = 0; 93 #endif /* INSECURE */ 94 } 95 96 SYSCTL_SETUP(sysctl_security_securelevel_setup, 97 "sysctl security securelevel setup") 98 { 99 /* 100 * For compatibility, we create a kern.securelevel variable. 101 */ 102 sysctl_createv(clog, 0, NULL, NULL, 103 CTLFLAG_PERMANENT, 104 CTLTYPE_NODE, "kern", NULL, 105 NULL, 0, NULL, 0, 106 CTL_KERN, CTL_EOL); 107 108 sysctl_createv(clog, 0, NULL, NULL, 109 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 110 CTLTYPE_INT, "securelevel", 111 SYSCTL_DESCR("System security level"), 112 secmodel_securelevel_sysctl, 0, NULL, 0, 113 CTL_KERN, KERN_SECURELVL, CTL_EOL); 114 } 115 116 void 117 secmodel_securelevel_start(void) 118 { 119 l_system = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 120 secmodel_securelevel_system_cb, NULL); 121 l_process = kauth_listen_scope(KAUTH_SCOPE_PROCESS, 122 secmodel_securelevel_process_cb, NULL); 123 l_network = kauth_listen_scope(KAUTH_SCOPE_NETWORK, 124 secmodel_securelevel_network_cb, NULL); 125 l_machdep = kauth_listen_scope(KAUTH_SCOPE_MACHDEP, 126 secmodel_securelevel_machdep_cb, NULL); 127 l_device = kauth_listen_scope(KAUTH_SCOPE_DEVICE, 128 secmodel_securelevel_device_cb, NULL); 129 } 130 131 #if defined(_LKM) 132 void 133 secmodel_securelevel_stop(void) 134 { 135 kauth_unlisten_scope(l_system); 136 kauth_unlisten_scope(l_process); 137 kauth_unlisten_scope(l_network); 138 kauth_unlisten_scope(l_machdep); 139 kauth_unlisten_scope(l_device); 140 } 141 #endif /* _LKM */ 142 143 /* 144 * kauth(9) listener 145 * 146 * Security model: Traditional NetBSD 147 * Scope: System 148 * Responsibility: Securelevel 149 */ 150 int 151 secmodel_securelevel_system_cb(kauth_cred_t cred, 152 kauth_action_t action, void *cookie, void *arg0, void *arg1, 153 void *arg2, void *arg3) 154 { 155 int result; 156 enum kauth_system_req req; 157 158 result = KAUTH_RESULT_DEFER; 159 req = (enum kauth_system_req)arg0; 160 161 switch (action) { 162 case KAUTH_SYSTEM_CHSYSFLAGS: 163 if (securelevel > 0) 164 result = KAUTH_RESULT_DENY; 165 break; 166 167 case KAUTH_SYSTEM_TIME: 168 switch (req) { 169 case KAUTH_REQ_SYSTEM_TIME_BACKWARDS: 170 if (securelevel > 1) 171 result = KAUTH_RESULT_DENY; 172 break; 173 174 case KAUTH_REQ_SYSTEM_TIME_RTCOFFSET: 175 if (securelevel > 0) 176 result = KAUTH_RESULT_DENY; 177 break; 178 179 default: 180 break; 181 } 182 break; 183 184 case KAUTH_SYSTEM_LKM: 185 if (securelevel > 0) 186 result = KAUTH_RESULT_DENY; 187 break; 188 189 case KAUTH_SYSTEM_MOUNT: 190 switch (req) { 191 case KAUTH_REQ_SYSTEM_MOUNT_NEW: 192 if (securelevel > 1) 193 result = KAUTH_RESULT_DENY; 194 195 break; 196 197 case KAUTH_REQ_SYSTEM_MOUNT_UPDATE: 198 if (securelevel > 1) { 199 struct mount *mp = arg1; 200 u_long flags = (u_long)arg2; 201 202 /* Can only degrade from read/write to read-only. */ 203 if (flags != (mp->mnt_flag | MNT_RDONLY | MNT_RELOAD | 204 MNT_FORCE | MNT_UPDATE)) 205 result = KAUTH_RESULT_DENY; 206 } 207 208 break; 209 210 default: 211 break; 212 } 213 214 break; 215 216 case KAUTH_SYSTEM_SYSCTL: 217 switch (req) { 218 case KAUTH_REQ_SYSTEM_SYSCTL_ADD: 219 case KAUTH_REQ_SYSTEM_SYSCTL_DELETE: 220 case KAUTH_REQ_SYSTEM_SYSCTL_DESC: 221 if (securelevel > 0) 222 result = KAUTH_RESULT_DENY; 223 break; 224 225 default: 226 break; 227 } 228 break; 229 230 case KAUTH_SYSTEM_SETIDCORE: 231 if (securelevel > 0) 232 result = KAUTH_RESULT_DENY; 233 break; 234 235 case KAUTH_SYSTEM_DEBUG: 236 switch (req) { 237 case KAUTH_REQ_SYSTEM_DEBUG_IPKDB: 238 if (securelevel > 0) 239 result = KAUTH_RESULT_DENY; 240 break; 241 242 default: 243 break; 244 } 245 break; 246 } 247 248 return (result); 249 } 250 251 /* 252 * kauth(9) listener 253 * 254 * Security model: Traditional NetBSD 255 * Scope: Process 256 * Responsibility: Securelevel 257 */ 258 int 259 secmodel_securelevel_process_cb(kauth_cred_t cred, 260 kauth_action_t action, void *cookie, void *arg0, 261 void *arg1, void *arg2, void *arg3) 262 { 263 struct proc *p; 264 int result; 265 266 result = KAUTH_RESULT_DEFER; 267 p = arg0; 268 269 switch (action) { 270 case KAUTH_PROCESS_CANPROCFS: { 271 enum kauth_process_req req; 272 273 req = (enum kauth_process_req)arg2; 274 switch (req) { 275 case KAUTH_REQ_PROCESS_CANPROCFS_READ: 276 break; 277 278 case KAUTH_REQ_PROCESS_CANPROCFS_RW: 279 case KAUTH_REQ_PROCESS_CANPROCFS_WRITE: 280 if ((p == initproc) && (securelevel > -1)) 281 result = KAUTH_RESULT_DENY; 282 283 break; 284 285 default: 286 break; 287 } 288 289 break; 290 } 291 292 case KAUTH_PROCESS_CANPTRACE: 293 case KAUTH_PROCESS_CANSYSTRACE: 294 if ((p == initproc) && (securelevel >= 0)) 295 result = KAUTH_RESULT_DENY; 296 297 break; 298 299 case KAUTH_PROCESS_CORENAME: 300 if (securelevel > 1) 301 result = KAUTH_RESULT_DENY; 302 break; 303 } 304 305 return (result); 306 } 307 308 /* 309 * kauth(9) listener 310 * 311 * Security model: Traditional NetBSD 312 * Scope: Network 313 * Responsibility: Securelevel 314 */ 315 int 316 secmodel_securelevel_network_cb(kauth_cred_t cred, 317 kauth_action_t action, void *cookie, void *arg0, 318 void *arg1, void *arg2, void *arg3) 319 { 320 int result; 321 enum kauth_network_req req; 322 323 result = KAUTH_RESULT_DEFER; 324 req = (enum kauth_network_req)arg0; 325 326 switch (action) { 327 case KAUTH_NETWORK_FIREWALL: 328 switch (req) { 329 case KAUTH_REQ_NETWORK_FIREWALL_FW: 330 case KAUTH_REQ_NETWORK_FIREWALL_NAT: 331 if (securelevel > 1) 332 result = KAUTH_RESULT_DENY; 333 break; 334 335 default: 336 break; 337 } 338 break; 339 340 case KAUTH_NETWORK_FORWSRCRT: 341 if (securelevel > 0) 342 result = KAUTH_RESULT_DENY; 343 break; 344 } 345 346 return (result); 347 } 348 349 /* 350 * kauth(9) listener 351 * 352 * Security model: Traditional NetBSD 353 * Scope: Machdep 354 * Responsibility: Securelevel 355 */ 356 int 357 secmodel_securelevel_machdep_cb(kauth_cred_t cred, 358 kauth_action_t action, void *cookie, void *arg0, 359 void *arg1, void *arg2, void *arg3) 360 { 361 int result; 362 363 result = KAUTH_RESULT_DEFER; 364 365 switch (action) { 366 case KAUTH_MACHDEP_IOPERM_SET: 367 case KAUTH_MACHDEP_IOPL: 368 if (securelevel > 0) 369 result = KAUTH_RESULT_DENY; 370 break; 371 372 case KAUTH_MACHDEP_UNMANAGEDMEM: 373 if (securelevel > 0) 374 result = KAUTH_RESULT_DENY; 375 break; 376 } 377 378 return (result); 379 } 380 381 /* 382 * kauth(9) listener 383 * 384 * Security model: Traditional NetBSD 385 * Scope: Device 386 * Responsibility: Securelevel 387 */ 388 int 389 secmodel_securelevel_device_cb(kauth_cred_t cred, 390 kauth_action_t action, void *cookie, void *arg0, 391 void *arg1, void *arg2, void *arg3) 392 { 393 int result; 394 395 result = KAUTH_RESULT_DEFER; 396 397 switch (action) { 398 case KAUTH_DEVICE_RAWIO_SPEC: { 399 struct vnode *vp, *bvp; 400 enum kauth_device_req req; 401 dev_t dev; 402 int d_type; 403 404 req = (enum kauth_device_req)arg0; 405 vp = arg1; 406 407 KASSERT(vp != NULL); 408 409 dev = vp->v_un.vu_specinfo->si_rdev; 410 d_type = D_OTHER; 411 bvp = NULL; 412 413 /* Handle /dev/mem and /dev/kmem. */ 414 if ((vp->v_type == VCHR) && iskmemdev(dev)) { 415 switch (req) { 416 case KAUTH_REQ_DEVICE_RAWIO_SPEC_READ: 417 break; 418 419 case KAUTH_REQ_DEVICE_RAWIO_SPEC_WRITE: 420 case KAUTH_REQ_DEVICE_RAWIO_SPEC_RW: 421 if (securelevel > 0) 422 result = KAUTH_RESULT_DENY; 423 break; 424 } 425 426 break; 427 } 428 429 switch (req) { 430 case KAUTH_REQ_DEVICE_RAWIO_SPEC_READ: 431 break; 432 433 case KAUTH_REQ_DEVICE_RAWIO_SPEC_WRITE: 434 case KAUTH_REQ_DEVICE_RAWIO_SPEC_RW: 435 switch (vp->v_type) { 436 case VCHR: { 437 const struct cdevsw *cdev; 438 439 cdev = cdevsw_lookup(dev); 440 if (cdev != NULL) { 441 dev_t blkdev; 442 443 blkdev = devsw_chr2blk(dev); 444 if (blkdev != NODEV) { 445 vfinddev(blkdev, VBLK, &bvp); 446 if (bvp != NULL) 447 d_type = (cdev->d_flag 448 & D_TYPEMASK); 449 } 450 } 451 452 break; 453 } 454 case VBLK: { 455 const struct bdevsw *bdev; 456 457 bdev = bdevsw_lookup(dev); 458 if (bdev != NULL) 459 d_type = (bdev->d_flag & D_TYPEMASK); 460 461 bvp = vp; 462 463 break; 464 } 465 466 default: 467 break; 468 } 469 470 if (d_type != D_DISK) 471 break; 472 473 /* 474 * XXX: This is bogus. We should be failing the request 475 * XXX: not only if this specific slice is mounted, but 476 * XXX: if it's on a disk with any other mounted slice. 477 */ 478 if (vfs_mountedon(bvp) && (securelevel > 0)) 479 break; 480 481 if (securelevel > 1) 482 result = KAUTH_RESULT_DENY; 483 484 break; 485 } 486 487 break; 488 } 489 490 case KAUTH_DEVICE_RAWIO_PASSTHRU: 491 if (securelevel > 0) { 492 u_long bits; 493 494 bits = (u_long)arg0; 495 496 KASSERT(bits != 0); 497 KASSERT((bits & ~KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_ALL) == 0); 498 499 if (bits & ~KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_READCONF) 500 result = KAUTH_RESULT_DENY; 501 } 502 503 break; 504 } 505 506 return (result); 507 } 508
Indexes created Tue Sep 23 07:09:52 GMT 2025