1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.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 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/types.h>
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/proc.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/sx.h>
36 #include <sys/malloc.h>
37 #include <sys/queue.h>
38 #include <sys/jail.h>
39 #include <sys/osd.h>
40 #include <sys/priv.h>
41 #include <sys/zone.h>
42
43 #include <sys/policy.h>
44
45 static MALLOC_DEFINE(M_ZONES, "zones_data", "Zones data");
46
47 /*
48 * Structure to record list of ZFS datasets exported to a zone.
49 */
50 typedef struct zone_dataset {
51 LIST_ENTRY(zone_dataset) zd_next;
52 char zd_dataset[0];
53 } zone_dataset_t;
54
55 LIST_HEAD(zone_dataset_head, zone_dataset);
56
57 static int zone_slot;
58
59 int
zone_dataset_attach(struct ucred * cred,const char * dataset,int jailid)60 zone_dataset_attach(struct ucred *cred, const char *dataset, int jailid)
61 {
62 struct zone_dataset_head *head;
63 zone_dataset_t *zd, *zd2;
64 struct prison *pr;
65 int dofree, error;
66
67 if ((error = priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
68 return (error);
69
70 /* Allocate memory before we grab prison's mutex. */
71 zd = malloc(sizeof (*zd) + strlen(dataset) + 1, M_ZONES, M_WAITOK);
72
73 sx_slock(&allprison_lock);
74 pr = prison_find(jailid); /* Locks &pr->pr_mtx. */
75 sx_sunlock(&allprison_lock);
76 if (pr == NULL) {
77 free(zd, M_ZONES);
78 return (ENOENT);
79 }
80
81 head = osd_jail_get(pr, zone_slot);
82 if (head != NULL) {
83 dofree = 0;
84 LIST_FOREACH(zd2, head, zd_next) {
85 if (strcmp(dataset, zd2->zd_dataset) == 0) {
86 free(zd, M_ZONES);
87 error = EEXIST;
88 goto end;
89 }
90 }
91 } else {
92 dofree = 1;
93 prison_hold_locked(pr);
94 mtx_unlock(&pr->pr_mtx);
95 head = malloc(sizeof (*head), M_ZONES, M_WAITOK);
96 LIST_INIT(head);
97 mtx_lock(&pr->pr_mtx);
98 error = osd_jail_set(pr, zone_slot, head);
99 KASSERT(error == 0, ("osd_jail_set() failed (error=%d)",
100 error));
101 }
102 strcpy(zd->zd_dataset, dataset);
103 LIST_INSERT_HEAD(head, zd, zd_next);
104 end:
105 if (dofree)
106 prison_free_locked(pr);
107 else
108 mtx_unlock(&pr->pr_mtx);
109 return (error);
110 }
111
112 int
zone_dataset_detach(struct ucred * cred,const char * dataset,int jailid)113 zone_dataset_detach(struct ucred *cred, const char *dataset, int jailid)
114 {
115 struct zone_dataset_head *head;
116 zone_dataset_t *zd;
117 struct prison *pr;
118 int error;
119
120 if ((error = priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
121 return (error);
122
123 sx_slock(&allprison_lock);
124 pr = prison_find(jailid);
125 sx_sunlock(&allprison_lock);
126 if (pr == NULL)
127 return (ENOENT);
128 head = osd_jail_get(pr, zone_slot);
129 if (head == NULL) {
130 error = ENOENT;
131 goto end;
132 }
133 LIST_FOREACH(zd, head, zd_next) {
134 if (strcmp(dataset, zd->zd_dataset) == 0)
135 break;
136 }
137 if (zd == NULL)
138 error = ENOENT;
139 else {
140 LIST_REMOVE(zd, zd_next);
141 free(zd, M_ZONES);
142 if (LIST_EMPTY(head))
143 osd_jail_del(pr, zone_slot);
144 error = 0;
145 }
146 end:
147 mtx_unlock(&pr->pr_mtx);
148 return (error);
149 }
150
151 /*
152 * Returns true if the named dataset is visible in the current zone.
153 * The 'write' parameter is set to 1 if the dataset is also writable.
154 */
155 int
zone_dataset_visible(const char * dataset,int * write)156 zone_dataset_visible(const char *dataset, int *write)
157 {
158 struct zone_dataset_head *head;
159 zone_dataset_t *zd;
160 struct prison *pr;
161 size_t len;
162 int ret = 0;
163
164 if (dataset[0] == '\0')
165 return (0);
166 if (INGLOBALZONE(curproc)) {
167 if (write != NULL)
168 *write = 1;
169 return (1);
170 }
171 pr = curthread->td_ucred->cr_prison;
172 mtx_lock(&pr->pr_mtx);
173 head = osd_jail_get(pr, zone_slot);
174 if (head == NULL)
175 goto end;
176
177 /*
178 * Walk the list once, looking for datasets which match exactly, or
179 * specify a dataset underneath an exported dataset. If found, return
180 * true and note that it is writable.
181 */
182 LIST_FOREACH(zd, head, zd_next) {
183 len = strlen(zd->zd_dataset);
184 if (strlen(dataset) >= len &&
185 memcmp(dataset, zd->zd_dataset, len) == 0 &&
186 (dataset[len] == '\0' || dataset[len] == '/' ||
187 dataset[len] == '@')) {
188 if (write)
189 *write = 1;
190 ret = 1;
191 goto end;
192 }
193 }
194
195 /*
196 * Walk the list a second time, searching for datasets which are parents
197 * of exported datasets. These should be visible, but read-only.
198 *
199 * Note that we also have to support forms such as 'pool/dataset/', with
200 * a trailing slash.
201 */
202 LIST_FOREACH(zd, head, zd_next) {
203 len = strlen(dataset);
204 if (dataset[len - 1] == '/')
205 len--; /* Ignore trailing slash */
206 if (len < strlen(zd->zd_dataset) &&
207 memcmp(dataset, zd->zd_dataset, len) == 0 &&
208 zd->zd_dataset[len] == '/') {
209 if (write)
210 *write = 0;
211 ret = 1;
212 goto end;
213 }
214 }
215 end:
216 mtx_unlock(&pr->pr_mtx);
217 return (ret);
218 }
219
220 static void
zone_destroy(void * arg)221 zone_destroy(void *arg)
222 {
223 struct zone_dataset_head *head;
224 zone_dataset_t *zd;
225
226 head = arg;
227 while ((zd = LIST_FIRST(head)) != NULL) {
228 LIST_REMOVE(zd, zd_next);
229 free(zd, M_ZONES);
230 }
231 free(head, M_ZONES);
232 }
233
234 uint32_t
zone_get_hostid(void * ptr)235 zone_get_hostid(void *ptr)
236 {
237
238 KASSERT(ptr == NULL, ("only NULL pointer supported in %s", __func__));
239
240 return ((uint32_t)curthread->td_ucred->cr_prison->pr_hostid);
241 }
242
243 static void
zone_sysinit(void * arg __unused)244 zone_sysinit(void *arg __unused)
245 {
246
247 zone_slot = osd_jail_register(zone_destroy, NULL);
248 }
249
250 static void
zone_sysuninit(void * arg __unused)251 zone_sysuninit(void *arg __unused)
252 {
253
254 osd_jail_deregister(zone_slot);
255 }
256
257 SYSINIT(zone_sysinit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysinit, NULL);
258 SYSUNINIT(zone_sysuninit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysuninit, NULL);
259