The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_jail.c

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    1 /*-
    2  * Copyright (c) 1999 Poul-Henning Kamp.
    3  * Copyright (c) 2008 Bjoern A. Zeeb.
    4  * Copyright (c) 2009 James Gritton.
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD: releng/11.1/sys/netinet/in_jail.c 316944 2017-04-14 22:02:08Z smh $");
   31 
   32 #include "opt_compat.h"
   33 #include "opt_ddb.h"
   34 #include "opt_inet.h"
   35 #include "opt_inet6.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/types.h>
   39 #include <sys/kernel.h>
   40 #include <sys/systm.h>
   41 #include <sys/errno.h>
   42 #include <sys/sysproto.h>
   43 #include <sys/malloc.h>
   44 #include <sys/osd.h>
   45 #include <sys/priv.h>
   46 #include <sys/proc.h>
   47 #include <sys/taskqueue.h>
   48 #include <sys/fcntl.h>
   49 #include <sys/jail.h>
   50 #include <sys/lock.h>
   51 #include <sys/mutex.h>
   52 #include <sys/racct.h>
   53 #include <sys/refcount.h>
   54 #include <sys/sx.h>
   55 #include <sys/sysent.h>
   56 #include <sys/namei.h>
   57 #include <sys/mount.h>
   58 #include <sys/queue.h>
   59 #include <sys/socket.h>
   60 #include <sys/syscallsubr.h>
   61 #include <sys/sysctl.h>
   62 #include <sys/vnode.h>
   63 
   64 #include <net/if.h>
   65 #include <net/vnet.h>
   66 
   67 #include <netinet/in.h>
   68 
   69 int
   70 prison_qcmp_v4(const void *ip1, const void *ip2)
   71 {
   72         in_addr_t iaa, iab;
   73 
   74         /*
   75          * We need to compare in HBO here to get the list sorted as expected
   76          * by the result of the code.  Sorting NBO addresses gives you
   77          * interesting results.  If you do not understand, do not try.
   78          */
   79         iaa = ntohl(((const struct in_addr *)ip1)->s_addr);
   80         iab = ntohl(((const struct in_addr *)ip2)->s_addr);
   81 
   82         /*
   83          * Do not simply return the difference of the two numbers, the int is
   84          * not wide enough.
   85          */
   86         if (iaa > iab)
   87                 return (1);
   88         else if (iaa < iab)
   89                 return (-1);
   90         else
   91                 return (0);
   92 }
   93 
   94 /*
   95  * Restrict a prison's IP address list with its parent's, possibly replacing
   96  * it.  Return true if the replacement buffer was used (or would have been).
   97  */
   98 int
   99 prison_restrict_ip4(struct prison *pr, struct in_addr *newip4)
  100 {
  101         int ii, ij, used;
  102         struct prison *ppr;
  103 
  104         ppr = pr->pr_parent;
  105         if (!(pr->pr_flags & PR_IP4_USER)) {
  106                 /* This has no user settings, so just copy the parent's list. */
  107                 if (pr->pr_ip4s < ppr->pr_ip4s) {
  108                         /*
  109                          * There's no room for the parent's list.  Use the
  110                          * new list buffer, which is assumed to be big enough
  111                          * (if it was passed).  If there's no buffer, try to
  112                          * allocate one.
  113                          */
  114                         used = 1;
  115                         if (newip4 == NULL) {
  116                                 newip4 = malloc(ppr->pr_ip4s * sizeof(*newip4),
  117                                     M_PRISON, M_NOWAIT);
  118                                 if (newip4 != NULL)
  119                                         used = 0;
  120                         }
  121                         if (newip4 != NULL) {
  122                                 bcopy(ppr->pr_ip4, newip4,
  123                                     ppr->pr_ip4s * sizeof(*newip4));
  124                                 free(pr->pr_ip4, M_PRISON);
  125                                 pr->pr_ip4 = newip4;
  126                                 pr->pr_ip4s = ppr->pr_ip4s;
  127                         }
  128                         return (used);
  129                 }
  130                 pr->pr_ip4s = ppr->pr_ip4s;
  131                 if (pr->pr_ip4s > 0)
  132                         bcopy(ppr->pr_ip4, pr->pr_ip4,
  133                             pr->pr_ip4s * sizeof(*newip4));
  134                 else if (pr->pr_ip4 != NULL) {
  135                         free(pr->pr_ip4, M_PRISON);
  136                         pr->pr_ip4 = NULL;
  137                 }
  138         } else if (pr->pr_ip4s > 0) {
  139                 /* Remove addresses that aren't in the parent. */
  140                 for (ij = 0; ij < ppr->pr_ip4s; ij++)
  141                         if (pr->pr_ip4[0].s_addr == ppr->pr_ip4[ij].s_addr)
  142                                 break;
  143                 if (ij < ppr->pr_ip4s)
  144                         ii = 1;
  145                 else {
  146                         bcopy(pr->pr_ip4 + 1, pr->pr_ip4,
  147                             --pr->pr_ip4s * sizeof(*pr->pr_ip4));
  148                         ii = 0;
  149                 }
  150                 for (ij = 1; ii < pr->pr_ip4s; ) {
  151                         if (pr->pr_ip4[ii].s_addr == ppr->pr_ip4[0].s_addr) {
  152                                 ii++;
  153                                 continue;
  154                         }
  155                         switch (ij >= ppr->pr_ip4s ? -1 :
  156                                 prison_qcmp_v4(&pr->pr_ip4[ii], &ppr->pr_ip4[ij])) {
  157                         case -1:
  158                                 bcopy(pr->pr_ip4 + ii + 1, pr->pr_ip4 + ii,
  159                                     (--pr->pr_ip4s - ii) * sizeof(*pr->pr_ip4));
  160                                 break;
  161                         case 0:
  162                                 ii++;
  163                                 ij++;
  164                                 break;
  165                         case 1:
  166                                 ij++;
  167                                 break;
  168                         }
  169                 }
  170                 if (pr->pr_ip4s == 0) {
  171                         free(pr->pr_ip4, M_PRISON);
  172                         pr->pr_ip4 = NULL;
  173                 }
  174         }
  175         return (0);
  176 }
  177 
  178 /*
  179  * Pass back primary IPv4 address of this jail.
  180  *
  181  * If not restricted return success but do not alter the address.  Caller has
  182  * to make sure to initialize it correctly (e.g. INADDR_ANY).
  183  *
  184  * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
  185  * Address returned in NBO.
  186  */
  187 int
  188 prison_get_ip4(struct ucred *cred, struct in_addr *ia)
  189 {
  190         struct prison *pr;
  191 
  192         KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
  193         KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
  194 
  195         pr = cred->cr_prison;
  196         if (!(pr->pr_flags & PR_IP4))
  197                 return (0);
  198         mtx_lock(&pr->pr_mtx);
  199         if (!(pr->pr_flags & PR_IP4)) {
  200                 mtx_unlock(&pr->pr_mtx);
  201                 return (0);
  202         }
  203         if (pr->pr_ip4 == NULL) {
  204                 mtx_unlock(&pr->pr_mtx);
  205                 return (EAFNOSUPPORT);
  206         }
  207 
  208         ia->s_addr = pr->pr_ip4[0].s_addr;
  209         mtx_unlock(&pr->pr_mtx);
  210         return (0);
  211 }
  212 
  213 /*
  214  * Return 1 if we should do proper source address selection or are not jailed.
  215  * We will return 0 if we should bypass source address selection in favour
  216  * of the primary jail IPv4 address. Only in this case *ia will be updated and
  217  * returned in NBO.
  218  * Return EAFNOSUPPORT, in case this jail does not allow IPv4.
  219  */
  220 int
  221 prison_saddrsel_ip4(struct ucred *cred, struct in_addr *ia)
  222 {
  223         struct prison *pr;
  224         struct in_addr lia;
  225         int error;
  226 
  227         KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
  228         KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
  229 
  230         if (!jailed(cred))
  231                 return (1);
  232 
  233         pr = cred->cr_prison;
  234         if (pr->pr_flags & PR_IP4_SADDRSEL)
  235                 return (1);
  236 
  237         lia.s_addr = INADDR_ANY;
  238         error = prison_get_ip4(cred, &lia);
  239         if (error)
  240                 return (error);
  241         if (lia.s_addr == INADDR_ANY)
  242                 return (1);
  243 
  244         ia->s_addr = lia.s_addr;
  245         return (0);
  246 }
  247 
  248 /*
  249  * Return true if pr1 and pr2 have the same IPv4 address restrictions.
  250  */
  251 int
  252 prison_equal_ip4(struct prison *pr1, struct prison *pr2)
  253 {
  254 
  255         if (pr1 == pr2)
  256                 return (1);
  257 
  258         /*
  259          * No need to lock since the PR_IP4_USER flag can't be altered for
  260          * existing prisons.
  261          */
  262         while (pr1 != &prison0 &&
  263 #ifdef VIMAGE
  264                !(pr1->pr_flags & PR_VNET) &&
  265 #endif
  266                !(pr1->pr_flags & PR_IP4_USER))
  267                 pr1 = pr1->pr_parent;
  268         while (pr2 != &prison0 &&
  269 #ifdef VIMAGE
  270                !(pr2->pr_flags & PR_VNET) &&
  271 #endif
  272                !(pr2->pr_flags & PR_IP4_USER))
  273                 pr2 = pr2->pr_parent;
  274         return (pr1 == pr2);
  275 }
  276 
  277 /*
  278  * Make sure our (source) address is set to something meaningful to this
  279  * jail.
  280  *
  281  * Returns 0 if jail doesn't restrict IPv4 or if address belongs to jail,
  282  * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
  283  * doesn't allow IPv4.  Address passed in in NBO and returned in NBO.
  284  */
  285 int
  286 prison_local_ip4(struct ucred *cred, struct in_addr *ia)
  287 {
  288         struct prison *pr;
  289         struct in_addr ia0;
  290         int error;
  291 
  292         KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
  293         KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
  294 
  295         pr = cred->cr_prison;
  296         if (!(pr->pr_flags & PR_IP4))
  297                 return (0);
  298         mtx_lock(&pr->pr_mtx);
  299         if (!(pr->pr_flags & PR_IP4)) {
  300                 mtx_unlock(&pr->pr_mtx);
  301                 return (0);
  302         }
  303         if (pr->pr_ip4 == NULL) {
  304                 mtx_unlock(&pr->pr_mtx);
  305                 return (EAFNOSUPPORT);
  306         }
  307 
  308         ia0.s_addr = ntohl(ia->s_addr);
  309 
  310         if (ia0.s_addr == INADDR_ANY) {
  311                 /*
  312                  * In case there is only 1 IPv4 address, bind directly.
  313                  */
  314                 if (pr->pr_ip4s == 1)
  315                         ia->s_addr = pr->pr_ip4[0].s_addr;
  316                 mtx_unlock(&pr->pr_mtx);
  317                 return (0);
  318         }
  319 
  320         error = prison_check_ip4_locked(pr, ia);
  321         if (error == EADDRNOTAVAIL && ia0.s_addr == INADDR_LOOPBACK) {
  322                 ia->s_addr = pr->pr_ip4[0].s_addr;
  323                 error = 0;
  324         }
  325 
  326         mtx_unlock(&pr->pr_mtx);
  327         return (error);
  328 }
  329 
  330 /*
  331  * Rewrite destination address in case we will connect to loopback address.
  332  *
  333  * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
  334  * Address passed in in NBO and returned in NBO.
  335  */
  336 int
  337 prison_remote_ip4(struct ucred *cred, struct in_addr *ia)
  338 {
  339         struct prison *pr;
  340 
  341         KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
  342         KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
  343 
  344         pr = cred->cr_prison;
  345         if (!(pr->pr_flags & PR_IP4))
  346                 return (0);
  347         mtx_lock(&pr->pr_mtx);
  348         if (!(pr->pr_flags & PR_IP4)) {
  349                 mtx_unlock(&pr->pr_mtx);
  350                 return (0);
  351         }
  352         if (pr->pr_ip4 == NULL) {
  353                 mtx_unlock(&pr->pr_mtx);
  354                 return (EAFNOSUPPORT);
  355         }
  356 
  357         if (ntohl(ia->s_addr) == INADDR_LOOPBACK &&
  358             prison_check_ip4_locked(pr, ia) == EADDRNOTAVAIL) {
  359                 ia->s_addr = pr->pr_ip4[0].s_addr;
  360                 mtx_unlock(&pr->pr_mtx);
  361                 return (0);
  362         }
  363 
  364         /*
  365          * Return success because nothing had to be changed.
  366          */
  367         mtx_unlock(&pr->pr_mtx);
  368         return (0);
  369 }
  370 
  371 /*
  372  * Check if given address belongs to the jail referenced by cred/prison.
  373  *
  374  * Returns 0 if address belongs to jail,
  375  * EADDRNOTAVAIL if the address doesn't belong to the jail.
  376  */
  377 int
  378 prison_check_ip4_locked(const struct prison *pr, const struct in_addr *ia)
  379 {
  380         int i, a, z, d;
  381 
  382         /*
  383          * Check the primary IP.
  384          */
  385         if (pr->pr_ip4[0].s_addr == ia->s_addr)
  386                 return (0);
  387 
  388         /*
  389          * All the other IPs are sorted so we can do a binary search.
  390          */
  391         a = 0;
  392         z = pr->pr_ip4s - 2;
  393         while (a <= z) {
  394                 i = (a + z) / 2;
  395                 d = prison_qcmp_v4(&pr->pr_ip4[i+1], ia);
  396                 if (d > 0)
  397                         z = i - 1;
  398                 else if (d < 0)
  399                         a = i + 1;
  400                 else
  401                         return (0);
  402         }
  403 
  404         return (EADDRNOTAVAIL);
  405 }
  406 
  407 int
  408 prison_check_ip4(const struct ucred *cred, const struct in_addr *ia)
  409 {
  410         struct prison *pr;
  411         int error;
  412 
  413         KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
  414         KASSERT(ia != NULL, ("%s: ia is NULL", __func__));
  415 
  416         pr = cred->cr_prison;
  417         if (!(pr->pr_flags & PR_IP4))
  418                 return (0);
  419         mtx_lock(&pr->pr_mtx);
  420         if (!(pr->pr_flags & PR_IP4)) {
  421                 mtx_unlock(&pr->pr_mtx);
  422                 return (0);
  423         }
  424         if (pr->pr_ip4 == NULL) {
  425                 mtx_unlock(&pr->pr_mtx);
  426                 return (EAFNOSUPPORT);
  427         }
  428 
  429         error = prison_check_ip4_locked(pr, ia);
  430         mtx_unlock(&pr->pr_mtx);
  431         return (error);
  432 }

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