1 /* 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 */ 9 10 #include <sys/cdefs.h> 11 __FBSDID("$FreeBSD$"); 12 13 #include "opt_mac.h" 14 15 #include <sys/param.h> 16 #include <sys/types.h> 17 #include <sys/kernel.h> 18 #include <sys/systm.h> 19 #include <sys/errno.h> 20 #include <sys/sysproto.h> 21 #include <sys/mac.h> 22 #include <sys/malloc.h> 23 #include <sys/proc.h> 24 #include <sys/taskqueue.h> 25 #include <sys/jail.h> 26 #include <sys/lock.h> 27 #include <sys/mutex.h> 28 #include <sys/namei.h> 29 #include <sys/queue.h> 30 #include <sys/socket.h> 31 #include <sys/syscallsubr.h> 32 #include <sys/sysctl.h> 33 #include <sys/vnode.h> 34 #include <net/if.h> 35 #include <netinet/in.h> 36 37 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures"); 38 39 SYSCTL_DECL(_security); 40 SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0, 41 "Jail rules"); 42 43 mp_fixme("these variables need a lock") 44 45 int jail_set_hostname_allowed = 1; 46 SYSCTL_INT(_security_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW, 47 &jail_set_hostname_allowed, 0, 48 "Processes in jail can set their hostnames"); 49 50 int jail_socket_unixiproute_only = 1; 51 SYSCTL_INT(_security_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW, 52 &jail_socket_unixiproute_only, 0, 53 "Processes in jail are limited to creating UNIX/IPv4/route sockets only"); 54 55 int jail_sysvipc_allowed = 0; 56 SYSCTL_INT(_security_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW, 57 &jail_sysvipc_allowed, 0, 58 "Processes in jail can use System V IPC primitives"); 59 60 int jail_getfsstatroot_only = 1; 61 SYSCTL_INT(_security_jail, OID_AUTO, getfsstatroot_only, CTLFLAG_RW, 62 &jail_getfsstatroot_only, 0, 63 "Processes see only their root file system in getfsstat()"); 64 65 int jail_allow_raw_sockets = 0; 66 SYSCTL_INT(_security_jail, OID_AUTO, allow_raw_sockets, CTLFLAG_RW, 67 &jail_allow_raw_sockets, 0, 68 "Prison root can create raw sockets"); 69 70 /* allprison, lastprid, and prisoncount are protected by allprison_mtx. */ 71 struct prisonlist allprison; 72 struct mtx allprison_mtx; 73 int lastprid = 0; 74 int prisoncount = 0; 75 76 static void init_prison(void *); 77 static void prison_complete(void *context, int pending); 78 static struct prison *prison_find(int); 79 static int sysctl_jail_list(SYSCTL_HANDLER_ARGS); 80 81 static void 82 init_prison(void *data __unused) 83 { 84 85 mtx_init(&allprison_mtx, "allprison", NULL, MTX_DEF); 86 LIST_INIT(&allprison); 87 } 88 89 SYSINIT(prison, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_prison, NULL); 90 91 /* 92 * MPSAFE 93 * 94 * struct jail_args { 95 * struct jail *jail; 96 * }; 97 */ 98 int 99 jail(struct thread *td, struct jail_args *uap) 100 { 101 struct nameidata nd; 102 struct prison *pr, *tpr; 103 struct jail j; 104 struct jail_attach_args jaa; 105 int error, tryprid; 106 107 error = copyin(uap->jail, &j, sizeof(j)); 108 if (error) 109 return (error); 110 if (j.version != 0) 111 return (EINVAL); 112 113 MALLOC(pr, struct prison *, sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO); 114 mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF); 115 pr->pr_ref = 1; 116 error = copyinstr(j.path, &pr->pr_path, sizeof(pr->pr_path), 0); 117 if (error) 118 goto e_killmtx; 119 mtx_lock(&Giant); 120 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, pr->pr_path, td); 121 error = namei(&nd); 122 if (error) { 123 mtx_unlock(&Giant); 124 goto e_killmtx; 125 } 126 pr->pr_root = nd.ni_vp; 127 VOP_UNLOCK(nd.ni_vp, 0, td); 128 NDFREE(&nd, NDF_ONLY_PNBUF); 129 mtx_unlock(&Giant); 130 error = copyinstr(j.hostname, &pr->pr_host, sizeof(pr->pr_host), 0); 131 if (error) 132 goto e_dropvnref; 133 pr->pr_ip = j.ip_number; 134 pr->pr_linux = NULL; 135 pr->pr_securelevel = securelevel; 136 137 /* Determine next pr_id and add prison to allprison list. */ 138 mtx_lock(&allprison_mtx); 139 tryprid = lastprid + 1; 140 if (tryprid == JAIL_MAX) 141 tryprid = 1; 142 next: 143 LIST_FOREACH(tpr, &allprison, pr_list) { 144 if (tpr->pr_id == tryprid) { 145 tryprid++; 146 if (tryprid == JAIL_MAX) { 147 mtx_unlock(&allprison_mtx); 148 error = EAGAIN; 149 goto e_dropvnref; 150 } 151 goto next; 152 } 153 } 154 pr->pr_id = jaa.jid = lastprid = tryprid; 155 LIST_INSERT_HEAD(&allprison, pr, pr_list); 156 prisoncount++; 157 mtx_unlock(&allprison_mtx); 158 159 error = jail_attach(td, &jaa); 160 if (error) 161 goto e_dropprref; 162 mtx_lock(&pr->pr_mtx); 163 pr->pr_ref--; 164 mtx_unlock(&pr->pr_mtx); 165 td->td_retval[0] = jaa.jid; 166 return (0); 167 e_dropprref: 168 mtx_lock(&allprison_mtx); 169 LIST_REMOVE(pr, pr_list); 170 prisoncount--; 171 mtx_unlock(&allprison_mtx); 172 e_dropvnref: 173 mtx_lock(&Giant); 174 vrele(pr->pr_root); 175 mtx_unlock(&Giant); 176 e_killmtx: 177 mtx_destroy(&pr->pr_mtx); 178 FREE(pr, M_PRISON); 179 return (error); 180 } 181 182 /* 183 * MPSAFE 184 * 185 * struct jail_attach_args { 186 * int jid; 187 * }; 188 */ 189 int 190 jail_attach(struct thread *td, struct jail_attach_args *uap) 191 { 192 struct proc *p; 193 struct ucred *newcred, *oldcred; 194 struct prison *pr; 195 int error; 196 197 /* 198 * XXX: Note that there is a slight race here if two threads 199 * in the same privileged process attempt to attach to two 200 * different jails at the same time. It is important for 201 * user processes not to do this, or they might end up with 202 * a process root from one prison, but attached to the jail 203 * of another. 204 */ 205 error = suser(td); 206 if (error) 207 return (error); 208 209 p = td->td_proc; 210 mtx_lock(&allprison_mtx); 211 pr = prison_find(uap->jid); 212 if (pr == NULL) { 213 mtx_unlock(&allprison_mtx); 214 return (EINVAL); 215 } 216 pr->pr_ref++; 217 mtx_unlock(&pr->pr_mtx); 218 mtx_unlock(&allprison_mtx); 219 220 mtx_lock(&Giant); 221 vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY, td); 222 if ((error = change_dir(pr->pr_root, td)) != 0) 223 goto e_unlock; 224 #ifdef MAC 225 if ((error = mac_check_vnode_chroot(td->td_ucred, pr->pr_root))) 226 goto e_unlock; 227 #endif 228 VOP_UNLOCK(pr->pr_root, 0, td); 229 change_root(pr->pr_root, td); 230 mtx_unlock(&Giant); 231 232 newcred = crget(); 233 PROC_LOCK(p); 234 oldcred = p->p_ucred; 235 setsugid(p); 236 crcopy(newcred, oldcred); 237 newcred->cr_prison = pr; 238 p->p_ucred = newcred; 239 PROC_UNLOCK(p); 240 crfree(oldcred); 241 return (0); 242 e_unlock: 243 VOP_UNLOCK(pr->pr_root, 0, td); 244 mtx_unlock(&Giant); 245 mtx_lock(&pr->pr_mtx); 246 pr->pr_ref--; 247 mtx_unlock(&pr->pr_mtx); 248 return (error); 249 } 250 251 /* 252 * Returns a locked prison instance, or NULL on failure. 253 */ 254 static struct prison * 255 prison_find(int prid) 256 { 257 struct prison *pr; 258 259 mtx_assert(&allprison_mtx, MA_OWNED); 260 LIST_FOREACH(pr, &allprison, pr_list) { 261 if (pr->pr_id == prid) { 262 mtx_lock(&pr->pr_mtx); 263 return (pr); 264 } 265 } 266 return (NULL); 267 } 268 269 void 270 prison_free(struct prison *pr) 271 { 272 273 mtx_lock(&allprison_mtx); 274 mtx_lock(&pr->pr_mtx); 275 pr->pr_ref--; 276 if (pr->pr_ref == 0) { 277 LIST_REMOVE(pr, pr_list); 278 mtx_unlock(&pr->pr_mtx); 279 prisoncount--; 280 mtx_unlock(&allprison_mtx); 281 282 TASK_INIT(&pr->pr_task, 0, prison_complete, pr); 283 taskqueue_enqueue(taskqueue_swi, &pr->pr_task); 284 return; 285 } 286 mtx_unlock(&pr->pr_mtx); 287 mtx_unlock(&allprison_mtx); 288 } 289 290 static void 291 prison_complete(void *context, int pending) 292 { 293 struct prison *pr; 294 295 pr = (struct prison *)context; 296 297 mtx_lock(&Giant); 298 vrele(pr->pr_root); 299 mtx_unlock(&Giant); 300 301 mtx_destroy(&pr->pr_mtx); 302 if (pr->pr_linux != NULL) 303 FREE(pr->pr_linux, M_PRISON); 304 FREE(pr, M_PRISON); 305 } 306 307 void 308 prison_hold(struct prison *pr) 309 { 310 311 mtx_lock(&pr->pr_mtx); 312 pr->pr_ref++; 313 mtx_unlock(&pr->pr_mtx); 314 } 315 316 u_int32_t 317 prison_getip(struct ucred *cred) 318 { 319 320 return (cred->cr_prison->pr_ip); 321 } 322 323 int 324 prison_ip(struct ucred *cred, int flag, u_int32_t *ip) 325 { 326 u_int32_t tmp; 327 328 if (!jailed(cred)) 329 return (0); 330 if (flag) 331 tmp = *ip; 332 else 333 tmp = ntohl(*ip); 334 if (tmp == INADDR_ANY) { 335 if (flag) 336 *ip = cred->cr_prison->pr_ip; 337 else 338 *ip = htonl(cred->cr_prison->pr_ip); 339 return (0); 340 } 341 if (tmp == INADDR_LOOPBACK) { 342 if (flag) 343 *ip = cred->cr_prison->pr_ip; 344 else 345 *ip = htonl(cred->cr_prison->pr_ip); 346 return (0); 347 } 348 if (cred->cr_prison->pr_ip != tmp) 349 return (1); 350 return (0); 351 } 352 353 void 354 prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip) 355 { 356 u_int32_t tmp; 357 358 if (!jailed(cred)) 359 return; 360 if (flag) 361 tmp = *ip; 362 else 363 tmp = ntohl(*ip); 364 if (tmp == INADDR_LOOPBACK) { 365 if (flag) 366 *ip = cred->cr_prison->pr_ip; 367 else 368 *ip = htonl(cred->cr_prison->pr_ip); 369 return; 370 } 371 return; 372 } 373 374 int 375 prison_if(struct ucred *cred, struct sockaddr *sa) 376 { 377 struct sockaddr_in *sai; 378 int ok; 379 380 sai = (struct sockaddr_in *)sa; 381 if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only) 382 ok = 1; 383 else if (sai->sin_family != AF_INET) 384 ok = 0; 385 else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr)) 386 ok = 1; 387 else 388 ok = 0; 389 return (ok); 390 } 391 392 /* 393 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH. 394 */ 395 int 396 prison_check(struct ucred *cred1, struct ucred *cred2) 397 { 398 399 if (jailed(cred1)) { 400 if (!jailed(cred2)) 401 return (ESRCH); 402 if (cred2->cr_prison != cred1->cr_prison) 403 return (ESRCH); 404 } 405 406 return (0); 407 } 408 409 /* 410 * Return 1 if the passed credential is in a jail, otherwise 0. 411 */ 412 int 413 jailed(struct ucred *cred) 414 { 415 416 return (cred->cr_prison != NULL); 417 } 418 419 /* 420 * Return the correct hostname for the passed credential. 421 */ 422 void 423 getcredhostname(struct ucred *cred, char *buf, size_t size) 424 { 425 426 if (jailed(cred)) { 427 mtx_lock(&cred->cr_prison->pr_mtx); 428 strlcpy(buf, cred->cr_prison->pr_host, size); 429 mtx_unlock(&cred->cr_prison->pr_mtx); 430 } else 431 strlcpy(buf, hostname, size); 432 } 433 434 /* 435 * Return 1 if the passed credential can "see" the passed mountpoint 436 * when performing a getfsstat(); otherwise, 0. 437 */ 438 int 439 prison_check_mount(struct ucred *cred, struct mount *mp) 440 { 441 442 if (jail_getfsstatroot_only && cred->cr_prison != NULL) { 443 if (cred->cr_prison->pr_root->v_mount != mp) 444 return (0); 445 } 446 return (1); 447 } 448 449 static int 450 sysctl_jail_list(SYSCTL_HANDLER_ARGS) 451 { 452 struct xprison *xp, *sxp; 453 struct prison *pr; 454 int count, error; 455 456 mtx_assert(&Giant, MA_OWNED); 457 if (jailed(req->td->td_ucred)) 458 return (0); 459 retry: 460 mtx_lock(&allprison_mtx); 461 count = prisoncount; 462 mtx_unlock(&allprison_mtx); 463 464 if (count == 0) 465 return (0); 466 467 sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO); 468 mtx_lock(&allprison_mtx); 469 if (count != prisoncount) { 470 mtx_unlock(&allprison_mtx); 471 free(sxp, M_TEMP); 472 goto retry; 473 } 474 475 LIST_FOREACH(pr, &allprison, pr_list) { 476 mtx_lock(&pr->pr_mtx); 477 xp->pr_version = XPRISON_VERSION; 478 xp->pr_id = pr->pr_id; 479 strlcpy(xp->pr_path, pr->pr_path, sizeof(xp->pr_path)); 480 strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host)); 481 xp->pr_ip = pr->pr_ip; 482 mtx_unlock(&pr->pr_mtx); 483 xp++; 484 } 485 mtx_unlock(&allprison_mtx); 486 487 error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count); 488 free(sxp, M_TEMP); 489 if (error) 490 return (error); 491 return (0); 492 } 493 494 SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD, 495 NULL, 0, sysctl_jail_list, "S", "List of active jails"); 496 497 static int 498 sysctl_jail_jailed(SYSCTL_HANDLER_ARGS) 499 { 500 int error, injail; 501 502 injail = jailed(req->td->td_ucred); 503 error = SYSCTL_OUT(req, &injail, sizeof(injail)); 504 505 return (error); 506 } 507 SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD, 508 NULL, 0, sysctl_jail_jailed, "I", "Process in jail?"); 509