1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
24  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
25  * Copyright (c) 2014, 2021 by Delphix. All rights reserved.
26  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
27  * Copyright 2017 RackTop Systems.
28  * Copyright (c) 2018 Datto Inc.
29  * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
30  */
31 
32 #include <dirent.h>
33 #include <dlfcn.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <libgen.h>
37 #include <libintl.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include <zone.h>
43 #include <sys/mntent.h>
44 #include <sys/mount.h>
45 #include <sys/stat.h>
46 #include <sys/vfs.h>
47 #include <sys/dsl_crypt.h>
48 #include <libzfs.h>
49 
50 #include "../../libzfs_impl.h"
51 #include <thread_pool.h>
52 
53 #define	ZS_COMMENT	0x00000000	/* comment */
54 #define	ZS_ZFSUTIL	0x00000001	/* caller is zfs(8) */
55 
56 typedef struct option_map {
57 	const char *name;
58 	unsigned long mntmask;
59 	unsigned long zfsmask;
60 } option_map_t;
61 
62 static const option_map_t option_map[] = {
63 	/* Canonicalized filesystem independent options from mount(8) */
64 	{ MNTOPT_NOAUTO,	MS_COMMENT,	ZS_COMMENT	},
65 	{ MNTOPT_DEFAULTS,	MS_COMMENT,	ZS_COMMENT	},
66 	{ MNTOPT_NODEVICES,	MS_NODEV,	ZS_COMMENT	},
67 	{ MNTOPT_DEVICES,	MS_COMMENT,	ZS_COMMENT	},
68 	{ MNTOPT_DIRSYNC,	MS_DIRSYNC,	ZS_COMMENT	},
69 	{ MNTOPT_NOEXEC,	MS_NOEXEC,	ZS_COMMENT	},
70 	{ MNTOPT_EXEC,		MS_COMMENT,	ZS_COMMENT	},
71 	{ MNTOPT_GROUP,		MS_GROUP,	ZS_COMMENT	},
72 	{ MNTOPT_NETDEV,	MS_COMMENT,	ZS_COMMENT	},
73 	{ MNTOPT_NOFAIL,	MS_COMMENT,	ZS_COMMENT	},
74 	{ MNTOPT_NOSUID,	MS_NOSUID,	ZS_COMMENT	},
75 	{ MNTOPT_SUID,		MS_COMMENT,	ZS_COMMENT	},
76 	{ MNTOPT_OWNER,		MS_OWNER,	ZS_COMMENT	},
77 	{ MNTOPT_REMOUNT,	MS_REMOUNT,	ZS_COMMENT	},
78 	{ MNTOPT_RO,		MS_RDONLY,	ZS_COMMENT	},
79 	{ MNTOPT_RW,		MS_COMMENT,	ZS_COMMENT	},
80 	{ MNTOPT_SYNC,		MS_SYNCHRONOUS,	ZS_COMMENT	},
81 	{ MNTOPT_USER,		MS_USERS,	ZS_COMMENT	},
82 	{ MNTOPT_USERS,		MS_USERS,	ZS_COMMENT	},
83 	/* acl flags passed with util-linux-2.24 mount command */
84 	{ MNTOPT_ACL,		MS_POSIXACL,	ZS_COMMENT	},
85 	{ MNTOPT_NOACL,		MS_COMMENT,	ZS_COMMENT	},
86 	{ MNTOPT_POSIXACL,	MS_POSIXACL,	ZS_COMMENT	},
87 	/*
88 	 * Case sensitive options are just listed here to silently
89 	 * ignore the error if passed with zfs mount command.
90 	 */
91 	{ MNTOPT_CASESENSITIVE,		MS_COMMENT,	ZS_COMMENT	},
92 	{ MNTOPT_CASEINSENSITIVE,	MS_COMMENT,	ZS_COMMENT	},
93 	{ MNTOPT_CASEMIXED,		MS_COMMENT,	ZS_COMMENT	},
94 #ifdef MS_NOATIME
95 	{ MNTOPT_NOATIME,	MS_NOATIME,	ZS_COMMENT	},
96 	{ MNTOPT_ATIME,		MS_COMMENT,	ZS_COMMENT	},
97 #endif
98 #ifdef MS_NODIRATIME
99 	{ MNTOPT_NODIRATIME,	MS_NODIRATIME,	ZS_COMMENT	},
100 	{ MNTOPT_DIRATIME,	MS_COMMENT,	ZS_COMMENT	},
101 #endif
102 #ifdef MS_RELATIME
103 	{ MNTOPT_RELATIME,	MS_RELATIME,	ZS_COMMENT	},
104 	{ MNTOPT_NORELATIME,	MS_COMMENT,	ZS_COMMENT	},
105 #endif
106 #ifdef MS_STRICTATIME
107 	{ MNTOPT_STRICTATIME,	MS_STRICTATIME,	ZS_COMMENT	},
108 	{ MNTOPT_NOSTRICTATIME,	MS_COMMENT,	ZS_COMMENT	},
109 #endif
110 #ifdef MS_LAZYTIME
111 	{ MNTOPT_LAZYTIME,	MS_LAZYTIME,	ZS_COMMENT	},
112 #endif
113 	{ MNTOPT_CONTEXT,	MS_COMMENT,	ZS_COMMENT	},
114 	{ MNTOPT_FSCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
115 	{ MNTOPT_DEFCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
116 	{ MNTOPT_ROOTCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
117 #ifdef MS_I_VERSION
118 	{ MNTOPT_IVERSION,	MS_I_VERSION,	ZS_COMMENT	},
119 #endif
120 #ifdef MS_MANDLOCK
121 	{ MNTOPT_NBMAND,	MS_MANDLOCK,	ZS_COMMENT	},
122 	{ MNTOPT_NONBMAND,	MS_COMMENT,	ZS_COMMENT	},
123 #endif
124 	/* Valid options not found in mount(8) */
125 	{ MNTOPT_BIND,		MS_BIND,	ZS_COMMENT	},
126 #ifdef MS_REC
127 	{ MNTOPT_RBIND,		MS_BIND|MS_REC,	ZS_COMMENT	},
128 #endif
129 	{ MNTOPT_COMMENT,	MS_COMMENT,	ZS_COMMENT	},
130 #ifdef MS_NOSUB
131 	{ MNTOPT_NOSUB,		MS_NOSUB,	ZS_COMMENT	},
132 #endif
133 #ifdef MS_SILENT
134 	{ MNTOPT_QUIET,		MS_SILENT,	ZS_COMMENT	},
135 #endif
136 	/* Custom zfs options */
137 	{ MNTOPT_XATTR,		MS_COMMENT,	ZS_COMMENT	},
138 	{ MNTOPT_NOXATTR,	MS_COMMENT,	ZS_COMMENT	},
139 	{ MNTOPT_ZFSUTIL,	MS_COMMENT,	ZS_ZFSUTIL	},
140 	{ NULL,			0,		0		} };
141 
142 /*
143  * Break the mount option in to a name/value pair.  The name is
144  * validated against the option map and mount flags set accordingly.
145  */
146 static int
147 parse_option(char *mntopt, unsigned long *mntflags,
148     unsigned long *zfsflags, int sloppy)
149 {
150 	const option_map_t *opt;
151 	char *ptr, *name, *value = NULL;
152 	int error = 0;
153 
154 	name = strdup(mntopt);
155 	if (name == NULL)
156 		return (ENOMEM);
157 
158 	for (ptr = name; ptr && *ptr; ptr++) {
159 		if (*ptr == '=') {
160 			*ptr = '\0';
161 			value = ptr+1;
162 			VERIFY3P(value, !=, NULL);
163 			break;
164 		}
165 	}
166 
167 	for (opt = option_map; opt->name != NULL; opt++) {
168 		if (strncmp(name, opt->name, strlen(name)) == 0) {
169 			*mntflags |= opt->mntmask;
170 			*zfsflags |= opt->zfsmask;
171 			error = 0;
172 			goto out;
173 		}
174 	}
175 
176 	if (!sloppy)
177 		error = ENOENT;
178 out:
179 	/* If required further process on the value may be done here */
180 	free(name);
181 	return (error);
182 }
183 
184 /*
185  * Translate the mount option string in to MS_* mount flags for the
186  * kernel vfs.  When sloppy is non-zero unknown options will be ignored
187  * otherwise they are considered fatal are copied in to badopt.
188  */
189 int
190 zfs_parse_mount_options(const char *mntopts, unsigned long *mntflags,
191     unsigned long *zfsflags, int sloppy, char *badopt, char *mtabopt)
192 {
193 	int error = 0, quote = 0, flag = 0, count = 0;
194 	char *ptr, *opt, *opts;
195 
196 	opts = strdup(mntopts);
197 	if (opts == NULL)
198 		return (ENOMEM);
199 
200 	*mntflags = 0;
201 	opt = NULL;
202 
203 	/*
204 	 * Scan through all mount options which must be comma delimited.
205 	 * We must be careful to notice regions which are double quoted
206 	 * and skip commas in these regions.  Each option is then checked
207 	 * to determine if it is a known option.
208 	 */
209 	for (ptr = opts; ptr && !flag; ptr++) {
210 		if (opt == NULL)
211 			opt = ptr;
212 
213 		if (*ptr == '"')
214 			quote = !quote;
215 
216 		if (quote)
217 			continue;
218 
219 		if (*ptr == '\0')
220 			flag = 1;
221 
222 		if ((*ptr == ',') || (*ptr == '\0')) {
223 			*ptr = '\0';
224 
225 			error = parse_option(opt, mntflags, zfsflags, sloppy);
226 			if (error) {
227 				strcpy(badopt, opt);
228 				goto out;
229 
230 			}
231 
232 			if (!(*mntflags & MS_REMOUNT) &&
233 			    !(*zfsflags & ZS_ZFSUTIL) &&
234 			    mtabopt != NULL) {
235 				if (count > 0)
236 					strlcat(mtabopt, ",", MNT_LINE_MAX);
237 
238 				strlcat(mtabopt, opt, MNT_LINE_MAX);
239 				count++;
240 			}
241 
242 			opt = NULL;
243 		}
244 	}
245 
246 out:
247 	free(opts);
248 	return (error);
249 }
250 
251 static void
252 append_mntopt(const char *name, const char *val, char *mntopts,
253     char *mtabopt, boolean_t quote)
254 {
255 	char tmp[MNT_LINE_MAX];
256 
257 	snprintf(tmp, MNT_LINE_MAX, quote ? ",%s=\"%s\"" : ",%s=%s", name, val);
258 
259 	if (mntopts)
260 		strlcat(mntopts, tmp, MNT_LINE_MAX);
261 
262 	if (mtabopt)
263 		strlcat(mtabopt, tmp, MNT_LINE_MAX);
264 }
265 
266 static void
267 zfs_selinux_setcontext(zfs_handle_t *zhp, zfs_prop_t zpt, const char *name,
268     char *mntopts, char *mtabopt)
269 {
270 	char context[ZFS_MAXPROPLEN];
271 
272 	if (zfs_prop_get(zhp, zpt, context, sizeof (context),
273 	    NULL, NULL, 0, B_FALSE) == 0) {
274 		if (strcmp(context, "none") != 0)
275 			append_mntopt(name, context, mntopts, mtabopt, B_TRUE);
276 	}
277 }
278 
279 void
280 zfs_adjust_mount_options(zfs_handle_t *zhp, const char *mntpoint,
281     char *mntopts, char *mtabopt)
282 {
283 	char prop[ZFS_MAXPROPLEN];
284 
285 	/*
286 	 * Checks to see if the ZFS_PROP_SELINUX_CONTEXT exists
287 	 * if it does, create a tmp variable in case it's needed
288 	 * checks to see if the selinux context is set to the default
289 	 * if it is, allow the setting of the other context properties
290 	 * this is needed because the 'context' property overrides others
291 	 * if it is not the default, set the 'context' property
292 	 */
293 	if (zfs_prop_get(zhp, ZFS_PROP_SELINUX_CONTEXT, prop, sizeof (prop),
294 	    NULL, NULL, 0, B_FALSE) == 0) {
295 		if (strcmp(prop, "none") == 0) {
296 			zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_FSCONTEXT,
297 			    MNTOPT_FSCONTEXT, mntopts, mtabopt);
298 			zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_DEFCONTEXT,
299 			    MNTOPT_DEFCONTEXT, mntopts, mtabopt);
300 			zfs_selinux_setcontext(zhp,
301 			    ZFS_PROP_SELINUX_ROOTCONTEXT, MNTOPT_ROOTCONTEXT,
302 			    mntopts, mtabopt);
303 		} else {
304 			append_mntopt(MNTOPT_CONTEXT, prop,
305 			    mntopts, mtabopt, B_TRUE);
306 		}
307 	}
308 
309 	/* A hint used to determine an auto-mounted snapshot mount point */
310 	append_mntopt(MNTOPT_MNTPOINT, mntpoint, mntopts, NULL, B_FALSE);
311 }
312 
313 /*
314  * By default the filesystem by preparing the mount options (i.e. parsing
315  * some flags from the "opts" parameter into the "flags" parameter) and then
316  * directly calling the system call mount(2). We don't need the mount utility
317  * or update /etc/mtab, because this is a symlink on all modern systems.
318  *
319  * If the environment variable ZFS_MOUNT_HELPER is set, we fall back to the
320  * previous behavior:
321  * The filesystem is mounted by invoking the system mount utility rather
322  * than by the system call mount(2).  This ensures that the /etc/mtab
323  * file is correctly locked for the update.  Performing our own locking
324  * and /etc/mtab update requires making an unsafe assumption about how
325  * the mount utility performs its locking.  Unfortunately, this also means
326  * in the case of a mount failure we do not have the exact errno.  We must
327  * make due with return value from the mount process.
328  */
329 int
330 do_mount(zfs_handle_t *zhp, const char *mntpt, const char *opts, int flags)
331 {
332 	const char *src = zfs_get_name(zhp);
333 	int error = 0;
334 
335 	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
336 		char badopt[MNT_LINE_MAX] = {0};
337 		unsigned long mntflags = flags, zfsflags = 0;
338 		char myopts[MNT_LINE_MAX] = {0};
339 
340 		if (zfs_parse_mount_options(opts, &mntflags,
341 		    &zfsflags, 0, badopt, NULL)) {
342 			return (EINVAL);
343 		}
344 		strlcat(myopts, opts, MNT_LINE_MAX);
345 		zfs_adjust_mount_options(zhp, mntpt, myopts, NULL);
346 		if (mount(src, mntpt, MNTTYPE_ZFS, mntflags, myopts)) {
347 			return (errno);
348 		}
349 	} else {
350 		char *argv[9] = {
351 		    (char *)"/bin/mount",
352 		    (char *)"--no-canonicalize",
353 		    (char *)"-t", (char *)MNTTYPE_ZFS,
354 		    (char *)"-o", (char *)opts,
355 		    (char *)src,
356 		    (char *)mntpt,
357 		    (char *)NULL };
358 
359 		/* Return only the most critical mount error */
360 		error = libzfs_run_process(argv[0], argv,
361 		    STDOUT_VERBOSE|STDERR_VERBOSE);
362 		if (error) {
363 			if (error & MOUNT_FILEIO) {
364 				error = EIO;
365 			} else if (error & MOUNT_USER) {
366 				error = EINTR;
367 			} else if (error & MOUNT_SOFTWARE) {
368 				error = EPIPE;
369 			} else if (error & MOUNT_BUSY) {
370 				error = EBUSY;
371 			} else if (error & MOUNT_SYSERR) {
372 				error = EAGAIN;
373 			} else if (error & MOUNT_USAGE) {
374 				error = EINVAL;
375 			} else
376 				error = ENXIO; /* Generic error */
377 		}
378 	}
379 
380 	return (error);
381 }
382 
383 int
384 do_unmount(zfs_handle_t *zhp, const char *mntpt, int flags)
385 {
386 	(void) zhp;
387 
388 	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
389 		int rv = umount2(mntpt, flags);
390 
391 		return (rv < 0 ? errno : 0);
392 	}
393 
394 	char *argv[7] = {
395 	    (char *)"/bin/umount",
396 	    (char *)"-t", (char *)MNTTYPE_ZFS,
397 	    NULL, NULL, NULL, NULL };
398 	int rc, count = 3;
399 
400 	if (flags & MS_FORCE)
401 		argv[count++] = (char *)"-f";
402 
403 	if (flags & MS_DETACH)
404 		argv[count++] = (char *)"-l";
405 
406 	argv[count] = (char *)mntpt;
407 	rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE|STDERR_VERBOSE);
408 
409 	return (rc ? EINVAL : 0);
410 }
411 
412 int
413 zfs_mount_delegation_check(void)
414 {
415 	return ((geteuid() != 0) ? EACCES : 0);
416 }
417 
418 /* Called from the tail end of zpool_disable_datasets() */
419 void
420 zpool_disable_datasets_os(zpool_handle_t *zhp, boolean_t force)
421 {
422 	(void) zhp, (void) force;
423 }
424 
425 /* Called from the tail end of zfs_unmount() */
426 void
427 zpool_disable_volume_os(const char *name)
428 {
429 	(void) name;
430 }
431