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/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/types.h>
31#include <sys/param.h>
32#include <sys/kernel.h>
33#include <sys/systm.h>
34#include <sys/proc.h>
35#include <sys/lock.h>
36#include <sys/mutex.h>
37#include <sys/sx.h>
38#include <sys/malloc.h>
39#include <sys/queue.h>
40#include <sys/jail.h>
41#include <sys/osd.h>
42#include <sys/priv.h>
43#include <sys/zone.h>
44
45#include <sys/policy.h>
46
47static MALLOC_DEFINE(M_ZONES, "zones_data", "Zones data");
48
49/*
50 * Structure to record list of ZFS datasets exported to a zone.
51 */
52typedef struct zone_dataset {
53	LIST_ENTRY(zone_dataset) zd_next;
54	char	zd_dataset[0];
55} zone_dataset_t;
56
57LIST_HEAD(zone_dataset_head, zone_dataset);
58
59static int zone_slot;
60
61int
62zone_dataset_attach(struct ucred *cred, const char *dataset, int jailid)
63{
64	struct zone_dataset_head *head;
65	zone_dataset_t *zd, *zd2;
66	struct prison *pr;
67	int dofree, error;
68
69	if ((error = spl_priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
70		return (error);
71
72	/* Allocate memory before we grab prison's mutex. */
73	zd = malloc(sizeof (*zd) + strlen(dataset) + 1, M_ZONES, M_WAITOK);
74
75	sx_slock(&allprison_lock);
76	pr = prison_find(jailid);	/* Locks &pr->pr_mtx. */
77	sx_sunlock(&allprison_lock);
78	if (pr == NULL) {
79		free(zd, M_ZONES);
80		return (ENOENT);
81	}
82
83	head = osd_jail_get(pr, zone_slot);
84	if (head != NULL) {
85		dofree = 0;
86		LIST_FOREACH(zd2, head, zd_next) {
87			if (strcmp(dataset, zd2->zd_dataset) == 0) {
88				free(zd, M_ZONES);
89				error = EEXIST;
90				goto end;
91			}
92		}
93	} else {
94		dofree = 1;
95		prison_hold_locked(pr);
96		mtx_unlock(&pr->pr_mtx);
97		head = malloc(sizeof (*head), M_ZONES, M_WAITOK);
98		LIST_INIT(head);
99		mtx_lock(&pr->pr_mtx);
100		error = osd_jail_set(pr, zone_slot, head);
101		KASSERT(error == 0, ("osd_jail_set() failed (error=%d)",
102		    error));
103	}
104	strcpy(zd->zd_dataset, dataset);
105	LIST_INSERT_HEAD(head, zd, zd_next);
106end:
107	if (dofree)
108		prison_free_locked(pr);
109	else
110		mtx_unlock(&pr->pr_mtx);
111	return (error);
112}
113
114int
115zone_dataset_detach(struct ucred *cred, const char *dataset, int jailid)
116{
117	struct zone_dataset_head *head;
118	zone_dataset_t *zd;
119	struct prison *pr;
120	int error;
121
122	if ((error = spl_priv_check_cred(cred, PRIV_ZFS_JAIL)) != 0)
123		return (error);
124
125	sx_slock(&allprison_lock);
126	pr = prison_find(jailid);
127	sx_sunlock(&allprison_lock);
128	if (pr == NULL)
129		return (ENOENT);
130	head = osd_jail_get(pr, zone_slot);
131	if (head == NULL) {
132		error = ENOENT;
133		goto end;
134	}
135	LIST_FOREACH(zd, head, zd_next) {
136		if (strcmp(dataset, zd->zd_dataset) == 0)
137			break;
138	}
139	if (zd == NULL)
140		error = ENOENT;
141	else {
142		LIST_REMOVE(zd, zd_next);
143		free(zd, M_ZONES);
144		if (LIST_EMPTY(head))
145			osd_jail_del(pr, zone_slot);
146		error = 0;
147	}
148end:
149	mtx_unlock(&pr->pr_mtx);
150	return (error);
151}
152
153/*
154 * Returns true if the named dataset is visible in the current zone.
155 * The 'write' parameter is set to 1 if the dataset is also writable.
156 */
157int
158zone_dataset_visible(const char *dataset, int *write)
159{
160	struct zone_dataset_head *head;
161	zone_dataset_t *zd;
162	struct prison *pr;
163	size_t len;
164	int ret = 0;
165
166	if (dataset[0] == '\0')
167		return (0);
168	if (INGLOBALZONE(curproc)) {
169		if (write != NULL)
170			*write = 1;
171		return (1);
172	}
173	pr = curthread->td_ucred->cr_prison;
174	mtx_lock(&pr->pr_mtx);
175	head = osd_jail_get(pr, zone_slot);
176	if (head == NULL)
177		goto end;
178
179	/*
180	 * Walk the list once, looking for datasets which match exactly, or
181	 * specify a dataset underneath an exported dataset.  If found, return
182	 * true and note that it is writable.
183	 */
184	LIST_FOREACH(zd, head, zd_next) {
185		len = strlen(zd->zd_dataset);
186		if (strlen(dataset) >= len &&
187		    bcmp(dataset, zd->zd_dataset, len) == 0 &&
188		    (dataset[len] == '\0' || dataset[len] == '/' ||
189		    dataset[len] == '@')) {
190			if (write)
191				*write = 1;
192			ret = 1;
193			goto end;
194		}
195	}
196
197	/*
198	 * Walk the list a second time, searching for datasets which are parents
199	 * of exported datasets.  These should be visible, but read-only.
200	 *
201	 * Note that we also have to support forms such as 'pool/dataset/', with
202	 * a trailing slash.
203	 */
204	LIST_FOREACH(zd, head, zd_next) {
205		len = strlen(dataset);
206		if (dataset[len - 1] == '/')
207			len--;	/* Ignore trailing slash */
208		if (len < strlen(zd->zd_dataset) &&
209		    bcmp(dataset, zd->zd_dataset, len) == 0 &&
210		    zd->zd_dataset[len] == '/') {
211			if (write)
212				*write = 0;
213			ret = 1;
214			goto end;
215		}
216	}
217end:
218	mtx_unlock(&pr->pr_mtx);
219	return (ret);
220}
221
222static void
223zone_destroy(void *arg)
224{
225	struct zone_dataset_head *head;
226	zone_dataset_t *zd;
227
228	head = arg;
229	while ((zd = LIST_FIRST(head)) != NULL) {
230		LIST_REMOVE(zd, zd_next);
231		free(zd, M_ZONES);
232	}
233	free(head, M_ZONES);
234}
235
236uint32_t
237zone_get_hostid(void *ptr)
238{
239
240	KASSERT(ptr == NULL, ("only NULL pointer supported in %s", __func__));
241
242	return ((uint32_t)curthread->td_ucred->cr_prison->pr_hostid);
243}
244
245static void
246zone_sysinit(void *arg __unused)
247{
248
249	zone_slot = osd_jail_register(zone_destroy, NULL);
250}
251
252static void
253zone_sysuninit(void *arg __unused)
254{
255
256	osd_jail_deregister(zone_slot);
257}
258
259SYSINIT(zone_sysinit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysinit, NULL);
260SYSUNINIT(zone_sysuninit, SI_SUB_DRIVERS, SI_ORDER_ANY, zone_sysuninit, NULL);
261