module/os/freebsd/spl/spl_zone.c

   1 /*
   2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/types.h>
  28 #include <sys/param.h>
  29 #include <sys/kernel.h>
  30 #include <sys/systm.h>
  31 #include <sys/proc.h>
  32 #include <sys/lock.h>
  33 #include <sys/mutex.h>
  34 #include <sys/sx.h>
  35 #include <sys/malloc.h>
  36 #include <sys/queue.h>
  37 #include <sys/jail.h>
  38 #include <sys/osd.h>
  39 #include <sys/priv.h>
  40 #include <sys/zone.h>
  41
  42 #include <sys/policy.h>
  43
  44 static MALLOC_DEFINE(M_ZONES, "zones_data", "Zones data");
  45
  46 /*
  47  * Structure to record list of ZFS datasets exported to a zone.
  48  */
  49 typedef struct zone_dataset {
  50         LIST_ENTRY(zone_dataset) zd_next;
  51         char    zd_dataset[0];
  52 } zone_dataset_t;
  53
  54 LIST_HEAD(zone_dataset_head, zone_dataset);
  55
  56 static int zone_slot;
  57
  58 int
  59 zone_dataset_attach(struct ucred *cred, const char *dataset, int jailid)
  60 {
  61         struct zone_dataset_head *head;
  62         zone_dataset_t *zd, *zd2;
  63         struct prison *pr;
  64         int dofree, error;
  65
  66         if ((error = priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
  67                 return (error);
  68
  69         /* Allocate memory before we grab prison's mutex. */
  70         zd = malloc(sizeof (*zd) + strlen(dataset) + 1, M_ZONES, M_WAITOK);
  71
  72         sx_slock(&allprison_lock);
  73         pr = prison_find(jailid);       /* Locks &pr->pr_mtx. */
  74         sx_sunlock(&allprison_lock);
  75         if (pr == NULL) {
  76                 free(zd, M_ZONES);
  77                 return (ENOENT);
  78         }
  79
  80         head = osd_jail_get(pr, zone_slot);
  81         if (head != NULL) {
  82                 dofree = 0;
  83                 LIST_FOREACH(zd2, head, zd_next) {
  84                         if (strcmp(dataset, zd2->zd_dataset) == 0) {
  85                                 free(zd, M_ZONES);
  86                                 error = EEXIST;
  87                                 goto end;
  88                         }
  89                 }
  90         } else {
  91                 dofree = 1;
  92                 prison_hold_locked(pr);
  93                 mtx_unlock(&pr->pr_mtx);
  94                 head = malloc(sizeof (*head), M_ZONES, M_WAITOK);
  95                 LIST_INIT(head);
  96                 mtx_lock(&pr->pr_mtx);
  97                 error = osd_jail_set(pr, zone_slot, head);
  98                 KASSERT(error == 0, ("osd_jail_set() failed (error=%d)",
  99                     error));
 100         }
 101         strcpy(zd->zd_dataset, dataset);
 102         LIST_INSERT_HEAD(head, zd, zd_next);
 103 end:
 104         if (dofree)
 105                 prison_free_locked(pr);
 106         else
 107                 mtx_unlock(&pr->pr_mtx);
 108         return (error);
 109 }
 110
 111 int
 112 zone_dataset_detach(struct ucred *cred, const char *dataset, int jailid)
 113 {
 114         struct zone_dataset_head *head;
 115         zone_dataset_t *zd;
 116         struct prison *pr;
 117         int error;
 118
 119         if ((error = priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
 120                 return (error);
 121
 122         sx_slock(&allprison_lock);
 123         pr = prison_find(jailid);
 124         sx_sunlock(&allprison_lock);
 125         if (pr == NULL)
 126                 return (ENOENT);
 127         head = osd_jail_get(pr, zone_slot);
 128         if (head == NULL) {
 129                 error = ENOENT;
 130                 goto end;
 131         }
 132         LIST_FOREACH(zd, head, zd_next) {
 133                 if (strcmp(dataset, zd->zd_dataset) == 0)
 134                         break;
 135         }
 136         if (zd == NULL)
 137                 error = ENOENT;
 138         else {
 139                 LIST_REMOVE(zd, zd_next);
 140                 free(zd, M_ZONES);
 141                 if (LIST_EMPTY(head))
 142                         osd_jail_del(pr, zone_slot);
 143                 error = 0;
 144         }
 145 end:
 146         mtx_unlock(&pr->pr_mtx);
 147         return (error);
 148 }
 149
 150 /*
 151  * Returns true if the named dataset is visible in the current zone.
 152  * The 'write' parameter is set to 1 if the dataset is also writable.
 153  */
 154 int
 155 zone_dataset_visible(const char *dataset, int *write)
 156 {
 157         struct zone_dataset_head *head;
 158         zone_dataset_t *zd;
 159         struct prison *pr;
 160         size_t len;
 161         int ret = 0;
 162
 163         if (dataset[0] == '\0')
 164                 return (0);
 165         if (INGLOBALZONE(curproc)) {
 166                 if (write != NULL)
 167                         *write = 1;
 168                 return (1);
 169         }
 170         pr = curthread->td_ucred->cr_prison;
 171         mtx_lock(&pr->pr_mtx);
 172         head = osd_jail_get(pr, zone_slot);
 173         if (head == NULL)
 174                 goto end;
 175
 176         /*
 177          * Walk the list once, looking for datasets which match exactly, or
 178          * specify a dataset underneath an exported dataset.  If found, return
 179          * true and note that it is writable.
 180          */
 181         LIST_FOREACH(zd, head, zd_next) {
 182                 len = strlen(zd->zd_dataset);
 183                 if (strlen(dataset) >= len &&
 184                     memcmp(dataset, zd->zd_dataset, len) == 0 &&
 185                     (dataset[len] == '\0' || dataset[len] == '/' ||
 186                     dataset[len] == '@')) {
 187                         if (write)
 188                                 *write = 1;
 189                         ret = 1;
 190                         goto end;
 191                 }
 192         }
 193
 194         /*
 195          * Walk the list a second time, searching for datasets which are parents
 196          * of exported datasets.  These should be visible, but read-only.
 197          *
 198          * Note that we also have to support forms such as 'pool/dataset/', with
 199          * a trailing slash.
 200          */
 201         LIST_FOREACH(zd, head, zd_next) {
 202                 len = strlen(dataset);
 203                 if (dataset[len - 1] == '/')
 204                         len--;  /* Ignore trailing slash */
 205                 if (len < strlen(zd->zd_dataset) &&
 206                     memcmp(dataset, zd->zd_dataset, len) == 0 &&
 207                     zd->zd_dataset[len] == '/') {
 208                         if (write)
 209                                 *write = 0;
 210                         ret = 1;
 211                         goto end;
 212                 }
 213         }
 214 end:
 215         mtx_unlock(&pr->pr_mtx);
 216         return (ret);
 217 }
 218
 219 static void
 220 zone_destroy(void *arg)
 221 {
 222         struct zone_dataset_head *head;
 223         zone_dataset_t *zd;
 224
 225         head = arg;
 226         while ((zd = LIST_FIRST(head)) != NULL) {
 227                 LIST_REMOVE(zd, zd_next);
 228                 free(zd, M_ZONES);
 229         }
 230         free(head, M_ZONES);
 231 }
 232
 233 uint32_t
 234 zone_get_hostid(void *ptr)
 235 {
 236
 237         KASSERT(ptr == NULL, ("only NULL pointer supported in %s", __func__));
 238
 239         return ((uint32_t)curthread->td_ucred->cr_prison->pr_hostid);
 240 }
 241
 242 static void
 243 zone_sysinit(void *arg __unused)
 244 {
 245
 246         zone_slot = osd_jail_register(zone_destroy, NULL);
 247 }
 248
 249 static void
 250 zone_sysuninit(void *arg __unused)
 251 {
 252
 253         osd_jail_deregister(zone_slot);
 254 }
 255
 256 SYSINIT(zone_sysinit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysinit, NULL);
 257 SYSUNINIT(zone_sysuninit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysuninit, NULL);