sys/kern/kern_jail.c

   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 /*-
  11  * Copyright (c) 2006 Victor Balada Diaz <victor@bsdes.net>
  12  * All rights reserved.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36
  37 /*
  38  * $FreeBSD: src/sys/kern/kern_jail.c,v 1.6.2.3 2001/08/17 01:00:26 rwatson Exp $
  39  * $DragonFly: src/sys/kern/kern_jail.c,v 1.18 2007/02/16 23:41:02 victor Exp $
  40  */
  41
  42 #include "opt_inet6.h"
  43
  44 #include <sys/param.h>
  45 #include <sys/types.h>
  46 #include <sys/kernel.h>
  47 #include <sys/systm.h>
  48 #include <sys/errno.h>
  49 #include <sys/sysproto.h>
  50 #include <sys/malloc.h>
  51 #include <sys/nlookup.h>
  52 #include <sys/namecache.h>
  53 #include <sys/proc.h>
  54 #include <sys/jail.h>
  55 #include <sys/socket.h>
  56 #include <sys/sysctl.h>
  57 #include <sys/kern_syscall.h>
  58 #include <net/if.h>
  59 #include <netinet/in.h>
  60 #include <netinet6/in6_var.h>
  61
  62 static struct prison    *prison_find(int);
  63 static void             prison_ipcache_init(struct prison *);
  64
  65 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
  66
  67 SYSCTL_NODE(, OID_AUTO, jail, CTLFLAG_RW, 0,
  68     "Jail rules");
  69
  70 int     jail_set_hostname_allowed = 1;
  71 SYSCTL_INT(_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
  72     &jail_set_hostname_allowed, 0,
  73     "Processes in jail can set their hostnames");
  74
  75 int     jail_socket_unixiproute_only = 1;
  76 SYSCTL_INT(_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
  77     &jail_socket_unixiproute_only, 0,
  78     "Processes in jail are limited to creating UNIX/IPv[46]/route sockets only");
  79
  80 int     jail_sysvipc_allowed = 0;
  81 SYSCTL_INT(_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
  82     &jail_sysvipc_allowed, 0,
  83     "Processes in jail can use System V IPC primitives");
  84
  85 int    jail_chflags_allowed = 0;
  86 SYSCTL_INT(_jail, OID_AUTO, chflags_allowed, CTLFLAG_RW,
  87     &jail_chflags_allowed, 0,
  88     "Process in jail can set chflags(1)");
  89
  90 int     lastprid = 0;
  91 int     prisoncount = 0;
  92
  93 LIST_HEAD(prisonlist, prison);
  94 struct  prisonlist allprison = LIST_HEAD_INITIALIZER(&allprison);
  95
  96 static int
  97 kern_jail_attach(int jid)
  98 {
  99         struct proc *p = curthread->td_proc;
 100         struct prison *pr;
 101         int error;
 102
 103         pr = prison_find(jid);
 104         if (pr == NULL)
 105                 return(EINVAL);
 106
 107         error = kern_chroot(&pr->pr_root);
 108         if (error)
 109                 return(error);
 110
 111         prison_hold(pr);
 112         cratom(&p->p_ucred);
 113         p->p_ucred->cr_prison = pr;
 114         p->p_flag |= P_JAILED;
 115
 116         return(0);
 117 }
 118
 119 /*
 120  * jail()
 121  *
 122  * jail_args(syscallarg(struct jail *) jail)
 123  */
 124 int
 125 sys_jail(struct jail_args *uap)
 126 {
 127         struct prison *pr, *tpr;
 128         struct jail j;
 129         struct jail_v0 jv0;
 130         struct thread *td = curthread;
 131         int error, tryprid, i;
 132         uint32_t jversion;
 133         struct nlookupdata nd;
 134         /* Multiip */
 135         struct sockaddr_storage *uips; /* Userland ips */
 136         struct sockaddr_in ip4addr;
 137         struct jail_ip_storage *jip;
 138         /* Multiip */
 139
 140         error = suser(td);
 141         if (error) {
 142                 uap->sysmsg_result = -1;
 143                 return(error);
 144         }
 145         error = copyin(uap->jail, &jversion, sizeof jversion);
 146         if (error) {
 147                 uap->sysmsg_result = -1;
 148                 return(error);
 149         }
 150         pr = kmalloc(sizeof *pr , M_PRISON, M_WAITOK | M_ZERO);
 151         SLIST_INIT(&pr->pr_ips);
 152
 153         switch (jversion) {
 154         case 0:
 155                 error = copyin(uap->jail, &jv0, sizeof(struct jail_v0));
 156                 if (error)
 157                         goto bail;
 158                 jip = kmalloc(sizeof(*jip),  M_PRISON, M_WAITOK | M_ZERO);
 159                 ip4addr.sin_family = AF_INET;
 160                 ip4addr.sin_addr.s_addr = htonl(jv0.ip_number);
 161                 memcpy(&jip->ip, &ip4addr, sizeof(ip4addr));
 162                 SLIST_INSERT_HEAD(&pr->pr_ips, jip, entries);
 163                 break;
 164         case 1:
 165                 error = copyin(uap->jail, &j, sizeof(j));
 166                 if (error)
 167                         goto bail;
 168                 uips = kmalloc((sizeof(*uips) * j.n_ips), M_PRISON,
 169                                 M_WAITOK | M_ZERO);
 170                 error = copyin(j.ips, uips, (sizeof(*uips) * j.n_ips));
 171                 if (error) {
 172                         kfree(uips, M_PRISON);
 173                         goto bail;
 174                 }
 175                 for (i = 0; i < j.n_ips; i++) {
 176                         jip = kmalloc(sizeof(*jip),  M_PRISON,
 177                                       M_WAITOK | M_ZERO);
 178                         memcpy(&jip->ip, &uips[i], sizeof(*uips));
 179                         SLIST_INSERT_HEAD(&pr->pr_ips, jip, entries);
 180                 }
 181                 kfree(uips, M_PRISON);
 182                 break;
 183         default:
 184                 error = EINVAL;
 185                 goto bail;
 186         }
 187
 188         error = copyinstr(j.hostname, &pr->pr_host, sizeof pr->pr_host, 0);
 189         if (error)
 190                 goto bail;
 191         error = nlookup_init(&nd, j.path, UIO_USERSPACE, NLC_FOLLOW);
 192         if (error)
 193                 goto nlookup_init_clean;
 194         error = nlookup(&nd);
 195         if (error)
 196                 goto nlookup_init_clean;
 197         cache_copy(&nd.nl_nch, &pr->pr_root);
 198
 199         varsymset_init(&pr->pr_varsymset, NULL);
 200         prison_ipcache_init(pr);
 201
 202         tryprid = lastprid + 1;
 203         if (tryprid == JAIL_MAX)
 204                 tryprid = 1;
 205 next:
 206         LIST_FOREACH(tpr, &allprison, pr_list) {
 207                 if (tpr->pr_id != tryprid)
 208                         continue;
 209                 tryprid++;
 210                 if (tryprid == JAIL_MAX) {
 211                         error = ERANGE;
 212                         goto varsym_clean;
 213                 }
 214                 goto next;
 215         }
 216         pr->pr_id = lastprid = tryprid;
 217         LIST_INSERT_HEAD(&allprison, pr, pr_list);
 218         prisoncount++;
 219
 220         error = kern_jail_attach(pr->pr_id);
 221         if (error)
 222                 goto jail_attach_clean;
 223
 224         nlookup_done(&nd);
 225         uap->sysmsg_result = pr->pr_id;
 226         return (0);
 227
 228 jail_attach_clean:
 229         LIST_REMOVE(pr, pr_list);
 230 varsym_clean:
 231         varsymset_clean(&pr->pr_varsymset);
 232 nlookup_init_clean:
 233         nlookup_done(&nd);
 234 bail:
 235         /* Delete all ips */
 236         while (!SLIST_EMPTY(&pr->pr_ips)) {
 237                 jip = SLIST_FIRST(&pr->pr_ips);
 238                 SLIST_REMOVE_HEAD(&pr->pr_ips, entries);
 239                 FREE(jip, M_PRISON);
 240         }
 241         FREE(pr, M_PRISON);
 242         return(error);
 243 }
 244
 245 /*
 246  * int jail_attach(int jid);
 247  */
 248 int
 249 sys_jail_attach(struct jail_attach_args *uap)
 250 {
 251         struct thread *td = curthread;
 252         int error;
 253
 254         error = suser(td);
 255         if (error)
 256                 return(error);
 257
 258         return(kern_jail_attach(uap->jid));
 259 }
 260
 261 static void
 262 prison_ipcache_init(struct prison *pr)
 263 {
 264         struct jail_ip_storage *jis;
 265         struct sockaddr_in *ip4;
 266         struct sockaddr_in6 *ip6;
 267
 268         SLIST_FOREACH(jis, &pr->pr_ips, entries) {
 269                 switch (jis->ip.ss_family) {
 270                 case AF_INET:
 271                         ip4 = (struct sockaddr_in *)&jis->ip;
 272                         if ((ntohl(ip4->sin_addr.s_addr) >> IN_CLASSA_NSHIFT) ==
 273                             IN_LOOPBACKNET) {
 274                                 /* loopback address */
 275                                 if (pr->local_ip4 == NULL)
 276                                         pr->local_ip4 = ip4;
 277                         } else {
 278                                 /* public address */
 279                                 if (pr->nonlocal_ip4 == NULL)
 280                                         pr->nonlocal_ip4 = ip4;
 281                         }
 282                         break;
 283
 284                 case AF_INET6:
 285                         ip6 = (struct sockaddr_in6 *)&jis->ip;
 286                         if (IN6_IS_ADDR_LOOPBACK(&ip6->sin6_addr)) {
 287                                 /* loopback address */
 288                                 if (pr->local_ip6 == NULL)
 289                                         pr->local_ip6 = ip6;
 290                         } else {
 291                                 /* public address */
 292                                 if (pr->nonlocal_ip6 == NULL)
 293                                         pr->nonlocal_ip6 = ip6;
 294                         }
 295                         break;
 296                 }
 297         }
 298 }
 299
 300 /*
 301  * Changes INADDR_LOOPBACK for a valid jail address.
 302  * ip is in network byte order.
 303  * Returns 1 if the ip is among jail valid ips.
 304  * Returns 0 if is not among jail valid ips or
 305  * if couldn't replace INADDR_LOOPBACK for a valid
 306  * IP.
 307  */
 308 int
 309 prison_replace_wildcards(struct thread *td, struct sockaddr *ip)
 310 {
 311         struct sockaddr_in *ip4 = (struct sockaddr_in *)ip;
 312         struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)ip;
 313         struct prison *pr;
 314
 315         if (td->td_proc == NULL)
 316                 return (1);
 317         if ((pr = td->td_proc->p_ucred->cr_prison) == NULL)
 318                 return (1);
 319
 320         if ((ip->sa_family == AF_INET &&
 321             ip4->sin_addr.s_addr == htonl(INADDR_ANY)) ||
 322             (ip->sa_family == AF_INET6 &&
 323             IN6_IS_ADDR_UNSPECIFIED(&ip6->sin6_addr)))
 324                 return (1);
 325         if ((ip->sa_family == AF_INET &&
 326             ip4->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) ||
 327             (ip->sa_family == AF_INET6 &&
 328             IN6_IS_ADDR_LOOPBACK(&ip6->sin6_addr))) {
 329                 if (!prison_get_local(pr, ip->sa_family, ip) &&
 330                     !prison_get_nonlocal(pr, ip->sa_family, ip))
 331                         return(0);
 332                 else
 333                         return(1);
 334         }
 335         if (jailed_ip(pr, ip))
 336                 return(1);
 337         return(0);
 338 }
 339
 340 int
 341 prison_remote_ip(struct thread *td, struct sockaddr *ip)
 342 {
 343         struct sockaddr_in *ip4 = (struct sockaddr_in *)ip;
 344         struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)ip;
 345         struct prison *pr;
 346
 347         if (td == NULL || td->td_proc == NULL)
 348                 return(1);
 349         if ((pr = td->td_proc->p_ucred->cr_prison) == NULL)
 350                 return(1);
 351         if ((ip->sa_family == AF_INET &&
 352             ip4->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) ||
 353             (ip->sa_family == AF_INET6 &&
 354             IN6_IS_ADDR_LOOPBACK(&ip6->sin6_addr))) {
 355                 if (!prison_get_local(pr, ip->sa_family, ip) &&
 356                     !prison_get_nonlocal(pr, ip->sa_family, ip))
 357                         return(0);
 358                 else
 359                         return(1);
 360         }
 361         return(1);
 362 }
 363
 364 /*
 365  * Prison get non loopback ip:
 366  * - af is the address family of the ip we want (AF_INET|AF_INET6).
 367  * - If ip != NULL, put the first IP address that is not a loopback address
 368  *   into *ip.
 369  *
 370  * ip is in network by order and we don't touch it unless we find a valid ip.
 371  * No matter if ip == NULL or not, we return either a valid struct sockaddr *,
 372  * or NULL.  This struct may not be modified.
 373  */
 374 struct sockaddr *
 375 prison_get_nonlocal(struct prison *pr, sa_family_t af, struct sockaddr *ip)
 376 {
 377         struct sockaddr_in *ip4 = (struct sockaddr_in *)ip;
 378         struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)ip;
 379
 380         /* Check if it is cached */
 381         switch(af) {
 382         case AF_INET:
 383                 if (ip4 != NULL && pr->nonlocal_ip4 != NULL)
 384                         ip4->sin_addr.s_addr = pr->nonlocal_ip4->sin_addr.s_addr;
 385                 return (struct sockaddr *)pr->nonlocal_ip4;
 386
 387         case AF_INET6:
 388                 if (ip6 != NULL && pr->nonlocal_ip6 != NULL)
 389                         ip6->sin6_addr = pr->nonlocal_ip6->sin6_addr;
 390                 return (struct sockaddr *)pr->nonlocal_ip6;
 391         }
 392
 393         /* NOTREACHED */
 394         return NULL;
 395 }
 396
 397 /*
 398  * Prison get loopback ip.
 399  * - af is the address family of the ip we want (AF_INET|AF_INET6).
 400  * - If ip != NULL, put the first IP address that is not a loopback address
 401  *   into *ip.
 402  *
 403  * ip is in network by order and we don't touch it unless we find a valid ip.
 404  * No matter if ip == NULL or not, we return either a valid struct sockaddr *,
 405  * or NULL.  This struct may not be modified.
 406  */
 407 struct sockaddr *
 408 prison_get_local(struct prison *pr, sa_family_t af, struct sockaddr *ip)
 409 {
 410         struct sockaddr_in *ip4 = (struct sockaddr_in *)ip;
 411         struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)ip;
 412
 413         /* Check if it is cached */
 414         switch(af) {
 415         case AF_INET:
 416                 if (ip4 != NULL && pr->local_ip4 != NULL)
 417                         ip4->sin_addr.s_addr = pr->local_ip4->sin_addr.s_addr;
 418                 return (struct sockaddr *)pr->local_ip4;
 419
 420         case AF_INET6:
 421                 if (ip6 != NULL && pr->local_ip6 != NULL)
 422                         ip6->sin6_addr = pr->local_ip6->sin6_addr;
 423                 return (struct sockaddr *)pr->local_ip6;
 424         }
 425
 426         /* NOTREACHED */
 427         return NULL;
 428 }
 429
 430 /* Check if the IP is among ours, if it is return 1, else 0 */
 431 int
 432 jailed_ip(struct prison *pr, struct sockaddr *ip)
 433 {
 434         struct jail_ip_storage *jis;
 435         struct sockaddr_in *jip4, *ip4;
 436         struct sockaddr_in6 *jip6, *ip6;
 437
 438         if (pr == NULL)
 439                 return(0);
 440         ip4 = (struct sockaddr_in *)ip;
 441         ip6 = (struct sockaddr_in6 *)ip;
 442         SLIST_FOREACH(jis, &pr->pr_ips, entries) {
 443                 switch (ip->sa_family) {
 444                 case AF_INET:
 445                         jip4 = (struct sockaddr_in *) &jis->ip;
 446                         if (jip4->sin_family == AF_INET &&
 447                             ip4->sin_addr.s_addr == jip4->sin_addr.s_addr)
 448                                 return(1);
 449                         break;
 450                 case AF_INET6:
 451                         jip6 = (struct sockaddr_in6 *) &jis->ip;
 452                         if (jip6->sin6_family == AF_INET6 &&
 453                             IN6_ARE_ADDR_EQUAL(&ip6->sin6_addr,
 454                                                &jip6->sin6_addr))
 455                                 return(1);
 456                         break;
 457                 }
 458         }
 459         /* Ip not in list */
 460         return(0);
 461 }
 462
 463 int
 464 prison_if(struct ucred *cred, struct sockaddr *sa)
 465 {
 466         struct prison *pr;
 467         struct sockaddr_in *sai = (struct sockaddr_in*) sa;
 468
 469         pr = cred->cr_prison;
 470
 471         if (((sai->sin_family != AF_INET) && (sai->sin_family != AF_INET6))
 472             && jail_socket_unixiproute_only)
 473                 return(1);
 474         else if ((sai->sin_family != AF_INET) && (sai->sin_family != AF_INET6))
 475                 return(0);
 476         else if (jailed_ip(pr, sa))
 477                 return(0);
 478         return(1);
 479 }
 480
 481 /*
 482  * Returns a prison instance, or NULL on failure.
 483  */
 484 static struct prison *
 485 prison_find(int prid)
 486 {
 487         struct prison *pr;
 488
 489         LIST_FOREACH(pr, &allprison, pr_list) {
 490                 if (pr->pr_id == prid)
 491                         break;
 492         }
 493         return(pr);
 494 }
 495
 496 static int
 497 sysctl_jail_list(SYSCTL_HANDLER_ARGS)
 498 {
 499         struct jail_ip_storage *jip;
 500 #ifdef INET6
 501         struct sockaddr_in6 *jsin6;
 502 #endif
 503         struct sockaddr_in *jsin;
 504         struct proc *p;
 505         struct prison *pr;
 506         unsigned int jlssize, jlsused;
 507         int count, error;
 508         char *jls; /* Jail list */
 509         char *oip; /* Output ip */
 510         char *fullpath, *freepath;
 511
 512         jlsused = 0;
 513         p = curthread->td_proc;
 514
 515         if (jailed(p->p_ucred))
 516                 return (0);
 517 retry:
 518         count = prisoncount;
 519
 520         if (count == 0)
 521                 return(0);
 522
 523         jlssize = (count * 1024);
 524         jls = kmalloc(jlssize + 1, M_TEMP, M_WAITOK | M_ZERO);
 525         if (count < prisoncount) {
 526                 kfree(jls, M_TEMP);
 527                 goto retry;
 528         }
 529         count = prisoncount;
 530
 531         LIST_FOREACH(pr, &allprison, pr_list) {
 532                 error = cache_fullpath(p, &pr->pr_root, &fullpath, &freepath);
 533                 if (error)
 534                         continue;
 535                 if (jlsused && jlsused < jlssize)
 536                         jls[jlsused++] = '\n';
 537                 count = ksnprintf(jls + jlsused, (jlssize - jlsused),
 538                                  "%d %s %s",
 539                                  pr->pr_id, pr->pr_host, fullpath);
 540                 kfree(freepath, M_TEMP);
 541                 if (count < 0)
 542                         goto end;
 543                 jlsused += count;
 544
 545                 /* Copy the IPS */
 546                 SLIST_FOREACH(jip, &pr->pr_ips, entries) {
 547                         jsin = (struct sockaddr_in *)&jip->ip;
 548
 549                         switch(jsin->sin_family) {
 550                         case AF_INET:
 551                                 oip = inet_ntoa(jsin->sin_addr);
 552                                 break;
 553 #ifdef INET6
 554                         case AF_INET6:
 555                                 jsin6 = (struct sockaddr_in6 *)&jip->ip;
 556                                 oip = ip6_sprintf(&jsin6->sin6_addr);
 557                                 break;
 558 #endif
 559                         default:
 560                                 oip = "?family?";
 561                                 break;
 562                         }
 563
 564                         if ((jlssize - jlsused) < (strlen(oip) + 1)) {
 565                                 error = ERANGE;
 566                                 goto end;
 567                         }
 568                         count = ksnprintf(jls + jlsused, (jlssize - jlsused),
 569                                           " %s", oip);
 570                         if (count < 0)
 571                                 goto end;
 572                         jlsused += count;
 573                 }
 574         }
 575
 576         /*
 577          * The format is:
 578          * pr_id <SPC> hostname1 <SPC> PATH1 <SPC> IP1 <SPC> IP2\npr_id...
 579          */
 580         error = SYSCTL_OUT(req, jls, jlsused);
 581 end:
 582         kfree(jls, M_TEMP);
 583         return(error);
 584 }
 585
 586 SYSCTL_OID(_jail, OID_AUTO, list, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0,
 587            sysctl_jail_list, "A", "List of active jails");
 588
 589 void
 590 prison_hold(struct prison *pr)
 591 {
 592         pr->pr_ref++;
 593 }
 594
 595 void
 596 prison_free(struct prison *pr)
 597 {
 598         struct jail_ip_storage *jls;
 599         KKASSERT(pr->pr_ref >= 1);
 600
 601         if (--pr->pr_ref > 0)
 602                 return;
 603
 604         /* Delete all ips */
 605         while (!SLIST_EMPTY(&pr->pr_ips)) {
 606                 jls = SLIST_FIRST(&pr->pr_ips);
 607                 SLIST_REMOVE_HEAD(&pr->pr_ips, entries);
 608                 FREE(jls, M_PRISON);
 609         }
 610         LIST_REMOVE(pr, pr_list);
 611         prisoncount--;
 612
 613         if (pr->pr_linux != NULL)
 614                 kfree(pr->pr_linux, M_PRISON);
 615         varsymset_clean(&pr->pr_varsymset);
 616         cache_drop(&pr->pr_root);
 617         kfree(pr, M_PRISON);
 618 }