1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
|
/*-
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/priv.h>
#include <sys/vnode.h>
#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/jail.h>
#include <sys/policy.h>
#include <sys/zfs_vfsops.h>
int
secpolicy_nfs(struct ucred *cred)
{
return (priv_check_cred(cred, PRIV_NFS_DAEMON, 0));
}
int
secpolicy_zfs(struct ucred *cred)
{
return (priv_check_cred(cred, PRIV_VFS_MOUNT, 0));
}
int
secpolicy_sys_config(struct ucred *cred, int checkonly __unused)
{
return (priv_check_cred(cred, PRIV_ZFS_POOL_CONFIG, 0));
}
int
secpolicy_zinject(struct ucred *cred)
{
return (priv_check_cred(cred, PRIV_ZFS_INJECT, 0));
}
int
secpolicy_fs_unmount(struct ucred *cred, struct mount *vfsp __unused)
{
return (priv_check_cred(cred, PRIV_VFS_UNMOUNT, 0));
}
int
secpolicy_fs_owner(struct mount *mp, struct ucred *cred)
{
if (zfs_super_owner) {
if (cred->cr_uid == mp->mnt_cred->cr_uid &&
(!jailed(cred) ||
cred->cr_prison == mp->mnt_cred->cr_prison)) {
return (0);
}
}
return (priv_check_cred(cred, PRIV_VFS_MOUNT_OWNER, 0));
}
/*
* This check is done in kern_link(), so we could just return 0 here.
*/
extern int hardlink_check_uid;
int
secpolicy_basic_link(struct vnode *vp, struct ucred *cred)
{
if (!hardlink_check_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_LINK, 0));
}
int
secpolicy_vnode_stky_modify(struct ucred *cred)
{
return (EPERM);
}
int
secpolicy_vnode_remove(struct vnode *vp, struct ucred *cred)
{
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_ADMIN, 0));
}
int
secpolicy_vnode_access(struct ucred *cred, struct vnode *vp, uint64_t owner,
accmode_t accmode)
{
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
if ((accmode & VREAD) && priv_check_cred(cred, PRIV_VFS_READ, 0) != 0)
return (EACCES);
if ((accmode & VWRITE) &&
priv_check_cred(cred, PRIV_VFS_WRITE, 0) != 0) {
return (EACCES);
}
if (accmode & VEXEC) {
if (vp->v_type == VDIR) {
if (priv_check_cred(cred, PRIV_VFS_LOOKUP, 0) != 0) {
return (EACCES);
}
} else {
if (priv_check_cred(cred, PRIV_VFS_EXEC, 0) != 0) {
return (EACCES);
}
}
}
return (0);
}
int
secpolicy_vnode_setdac(struct vnode *vp, struct ucred *cred, uid_t owner)
{
if (owner == cred->cr_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_ADMIN, 0));
}
int
secpolicy_vnode_setattr(struct ucred *cred, struct vnode *vp, struct vattr *vap,
const struct vattr *ovap, int flags,
int unlocked_access(void *, int, struct ucred *), void *node)
{
int mask = vap->va_mask;
int error;
if (mask & AT_SIZE) {
if (vp->v_type == VDIR)
return (EISDIR);
error = unlocked_access(node, VWRITE, cred);
if (error)
return (error);
}
if (mask & AT_MODE) {
/*
* If not the owner of the file then check privilege
* for two things: the privilege to set the mode at all
* and, if we're setting setuid, we also need permissions
* to add the set-uid bit, if we're not the owner.
* In the specific case of creating a set-uid root
* file, we need even more permissions.
*/
error = secpolicy_vnode_setdac(vp, cred, ovap->va_uid);
if (error)
return (error);
error = secpolicy_setid_setsticky_clear(vp, vap, ovap, cred);
if (error)
return (error);
} else {
vap->va_mode = ovap->va_mode;
}
if (mask & (AT_UID | AT_GID)) {
error = secpolicy_vnode_setdac(vp, cred, ovap->va_uid);
if (error)
return (error);
/*
* To change the owner of a file, or change the group of a file to a
* group of which we are not a member, the caller must have
* privilege.
*/
if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) ||
((mask & AT_GID) && vap->va_gid != ovap->va_gid &&
!groupmember(vap->va_gid, cred))) {
if (secpolicy_fs_owner(vp->v_mount, cred) != 0) {
error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0);
if (error)
return (error);
}
}
if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) ||
((mask & AT_GID) && vap->va_gid != ovap->va_gid)) {
secpolicy_setid_clear(vap, vp, cred);
}
}
if (mask & (AT_ATIME | AT_MTIME)) {
/*
* From utimes(2):
* If times is NULL, ... The caller must be the owner of
* the file, have permission to write the file, or be the
* super-user.
* If times is non-NULL, ... The caller must be the owner of
* the file or be the super-user.
*/
error = secpolicy_vnode_setdac(vp, cred, ovap->va_uid);
if (error && (vap->va_vaflags & VA_UTIMES_NULL))
error = unlocked_access(node, VWRITE, cred);
if (error)
return (error);
}
return (0);
}
int
secpolicy_vnode_create_gid(struct ucred *cred)
{
return (EPERM);
}
int
secpolicy_vnode_setids_setgids(struct vnode *vp, struct ucred *cred, gid_t gid)
{
if (groupmember(gid, cred))
return (0);
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_SETGID, 0));
}
int
secpolicy_vnode_setid_retain(struct vnode *vp, struct ucred *cred,
boolean_t issuidroot __unused)
{
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_RETAINSUGID, 0));
}
void
secpolicy_setid_clear(struct vattr *vap, struct vnode *vp, struct ucred *cred)
{
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return;
if ((vap->va_mode & (S_ISUID | S_ISGID)) != 0) {
if (priv_check_cred(cred, PRIV_VFS_RETAINSUGID, 0)) {
vap->va_mask |= AT_MODE;
vap->va_mode &= ~(S_ISUID|S_ISGID);
}
}
}
int
secpolicy_setid_setsticky_clear(struct vnode *vp, struct vattr *vap,
const struct vattr *ovap, struct ucred *cred)
{
int error;
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
/*
* Privileged processes may set the sticky bit on non-directories,
* as well as set the setgid bit on a file with a group that the process
* is not a member of. Both of these are allowed in jail(8).
*/
if (vp->v_type != VDIR && (vap->va_mode & S_ISTXT)) {
if (priv_check_cred(cred, PRIV_VFS_STICKYFILE, 0))
return (EFTYPE);
}
/*
* Check for privilege if attempting to set the
* group-id bit.
*/
if ((vap->va_mode & S_ISGID) != 0) {
error = secpolicy_vnode_setids_setgids(vp, cred, ovap->va_gid);
if (error)
return (error);
}
return (0);
}
int
secpolicy_fs_mount(cred_t *cr, vnode_t *mvp, struct mount *vfsp)
{
return (priv_check_cred(cr, PRIV_VFS_MOUNT, 0));
}
int
secpolicy_vnode_owner(struct vnode *vp, cred_t *cred, uid_t owner)
{
if (owner == cred->cr_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
/* XXX: vfs_suser()? */
return (priv_check_cred(cred, PRIV_VFS_MOUNT_OWNER, 0));
}
int
secpolicy_vnode_chown(struct vnode *vp, cred_t *cred, boolean_t check_self)
{
if (secpolicy_fs_owner(vp->v_mount, cred) == 0)
return (0);
return (priv_check_cred(cred, PRIV_VFS_CHOWN, 0));
}
void
secpolicy_fs_mount_clearopts(cred_t *cr, struct mount *vfsp)
{
if (priv_check_cred(cr, PRIV_VFS_MOUNT_NONUSER, 0) != 0) {
MNT_ILOCK(vfsp);
vfsp->vfs_flag |= VFS_NOSETUID | MNT_USER;
vfs_clearmntopt(vfsp, MNTOPT_SETUID);
vfs_setmntopt(vfsp, MNTOPT_NOSETUID, NULL, 0);
MNT_IUNLOCK(vfsp);
}
}
/*
* Check privileges for setting xvattr attributes
*/
int
secpolicy_xvattr(xvattr_t *xvap, uid_t owner, cred_t *cr, vtype_t vtype)
{
return (priv_check_cred(cr, PRIV_VFS_SYSFLAGS, 0));
}
|
