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/priv.h> 30 #include <sys/vnode.h> 31 #include <sys/mntent.h> 32 #include <sys/mount.h> 33 #include <sys/stat.h> 34 #include <sys/jail.h> 35 #include <sys/policy.h> 36 #include <sys/zfs_vfsops.h> 37 #include <sys/zfs_znode.h> 38 39 40 int 41 secpolicy_nfs(cred_t *cr) 42 { 43 44 return (spl_priv_check_cred(cr, PRIV_NFS_DAEMON)); 45 } 46 47 int 48 secpolicy_zfs(cred_t *cr) 49 { 50 51 return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT)); 52 } 53 54 int 55 secpolicy_zfs_proc(cred_t *cr, proc_t *proc) 56 { 57 58 return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT)); 59 } 60 61 int 62 secpolicy_sys_config(cred_t *cr, int checkonly __unused) 63 { 64 65 return (spl_priv_check_cred(cr, PRIV_ZFS_POOL_CONFIG)); 66 } 67 68 int 69 secpolicy_zinject(cred_t *cr) 70 { 71 72 return (spl_priv_check_cred(cr, PRIV_ZFS_INJECT)); 73 } 74 75 int 76 secpolicy_fs_unmount(cred_t *cr, struct mount *vfsp __unused) 77 { 78 79 return (spl_priv_check_cred(cr, PRIV_VFS_UNMOUNT)); 80 } 81 82 int 83 secpolicy_fs_owner(struct mount *mp, cred_t *cr) 84 { 85 86 if (zfs_super_owner) { 87 if (cr->cr_uid == mp->mnt_cred->cr_uid && 88 cr->cr_prison == mp->mnt_cred->cr_prison) { 89 return (0); 90 } 91 } 92 return (EPERM); 93 } 94 95 /* 96 * This check is done in kern_link(), so we could just return 0 here. 97 */ 98 extern int hardlink_check_uid; 99 int 100 secpolicy_basic_link(vnode_t *vp, cred_t *cr) 101 { 102 103 if (!hardlink_check_uid) 104 return (0); 105 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 106 return (0); 107 return (spl_priv_check_cred(cr, PRIV_VFS_LINK)); 108 } 109 110 int 111 secpolicy_vnode_stky_modify(cred_t *cr) 112 { 113 114 return (EPERM); 115 } 116 117 int 118 secpolicy_vnode_remove(vnode_t *vp, cred_t *cr) 119 { 120 121 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 122 return (0); 123 return (spl_priv_check_cred(cr, PRIV_VFS_ADMIN)); 124 } 125 126 int 127 secpolicy_vnode_access(cred_t *cr, vnode_t *vp, uid_t owner, accmode_t accmode) 128 { 129 130 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 131 return (0); 132 133 if ((accmode & VREAD) && spl_priv_check_cred(cr, PRIV_VFS_READ) != 0) 134 return (EACCES); 135 if ((accmode & VWRITE) && 136 spl_priv_check_cred(cr, PRIV_VFS_WRITE) != 0) { 137 return (EACCES); 138 } 139 if (accmode & VEXEC) { 140 if (vp->v_type == VDIR) { 141 if (spl_priv_check_cred(cr, PRIV_VFS_LOOKUP) != 0) 142 return (EACCES); 143 } else { 144 if (spl_priv_check_cred(cr, PRIV_VFS_EXEC) != 0) 145 return (EACCES); 146 } 147 } 148 return (0); 149 } 150 151 /* 152 * Like secpolicy_vnode_access() but we get the actual wanted mode and the 153 * current mode of the file, not the missing bits. 154 */ 155 int 156 secpolicy_vnode_access2(cred_t *cr, vnode_t *vp, uid_t owner, 157 accmode_t curmode, accmode_t wantmode) 158 { 159 accmode_t mode; 160 161 mode = ~curmode & wantmode; 162 163 if (mode == 0) 164 return (0); 165 166 return (secpolicy_vnode_access(cr, vp, owner, mode)); 167 } 168 169 int 170 secpolicy_vnode_any_access(cred_t *cr, vnode_t *vp, uid_t owner) 171 { 172 static int privs[] = { 173 PRIV_VFS_ADMIN, 174 PRIV_VFS_READ, 175 PRIV_VFS_WRITE, 176 PRIV_VFS_EXEC, 177 PRIV_VFS_LOOKUP 178 }; 179 int i; 180 181 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 182 return (0); 183 184 /* Same as secpolicy_vnode_setdac */ 185 if (owner == cr->cr_uid) 186 return (0); 187 188 for (i = 0; i < sizeof (privs)/sizeof (int); i++) { 189 int priv; 190 191 switch (priv = privs[i]) { 192 case PRIV_VFS_EXEC: 193 if (vp->v_type == VDIR) 194 continue; 195 break; 196 case PRIV_VFS_LOOKUP: 197 if (vp->v_type != VDIR) 198 continue; 199 break; 200 } 201 if (spl_priv_check_cred(cr, priv) == 0) 202 return (0); 203 } 204 return (EPERM); 205 } 206 207 int 208 secpolicy_vnode_setdac(vnode_t *vp, cred_t *cr, uid_t owner) 209 { 210 211 if (owner == cr->cr_uid) 212 return (0); 213 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 214 return (0); 215 return (spl_priv_check_cred(cr, PRIV_VFS_ADMIN)); 216 } 217 218 int 219 secpolicy_vnode_setattr(cred_t *cr, vnode_t *vp, struct vattr *vap, 220 const struct vattr *ovap, int flags, 221 int unlocked_access(void *, int, cred_t *), void *node) 222 { 223 int mask = vap->va_mask; 224 int error; 225 226 if (mask & AT_SIZE) { 227 if (vp->v_type == VDIR) 228 return (EISDIR); 229 error = unlocked_access(node, VWRITE, cr); 230 if (error) 231 return (error); 232 } 233 if (mask & AT_MODE) { 234 /* 235 * If not the owner of the file then check privilege 236 * for two things: the privilege to set the mode at all 237 * and, if we're setting setuid, we also need permissions 238 * to add the set-uid bit, if we're not the owner. 239 * In the specific case of creating a set-uid root 240 * file, we need even more permissions. 241 */ 242 error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid); 243 if (error) 244 return (error); 245 error = secpolicy_setid_setsticky_clear(vp, vap, ovap, cr); 246 if (error) 247 return (error); 248 } else { 249 vap->va_mode = ovap->va_mode; 250 } 251 if (mask & (AT_UID | AT_GID)) { 252 error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid); 253 if (error) 254 return (error); 255 256 /* 257 * To change the owner of a file, or change the group of 258 * a file to a group of which we are not a member, the 259 * caller must have privilege. 260 */ 261 if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) || 262 ((mask & AT_GID) && vap->va_gid != ovap->va_gid && 263 !groupmember(vap->va_gid, cr))) { 264 if (secpolicy_fs_owner(vp->v_mount, cr) != 0) { 265 error = spl_priv_check_cred(cr, PRIV_VFS_CHOWN); 266 if (error) 267 return (error); 268 } 269 } 270 271 if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) || 272 ((mask & AT_GID) && vap->va_gid != ovap->va_gid)) { 273 secpolicy_setid_clear(vap, vp, cr); 274 } 275 } 276 if (mask & (AT_ATIME | AT_MTIME)) { 277 /* 278 * From utimes(2): 279 * If times is NULL, ... The caller must be the owner of 280 * the file, have permission to write the file, or be the 281 * super-user. 282 * If times is non-NULL, ... The caller must be the owner of 283 * the file or be the super-user. 284 */ 285 error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid); 286 if (error && (vap->va_vaflags & VA_UTIMES_NULL)) 287 error = unlocked_access(node, VWRITE, cr); 288 if (error) 289 return (error); 290 } 291 return (0); 292 } 293 294 int 295 secpolicy_vnode_create_gid(cred_t *cr) 296 { 297 298 return (EPERM); 299 } 300 301 int 302 secpolicy_vnode_setids_setgids(vnode_t *vp, cred_t *cr, gid_t gid) 303 { 304 305 if (groupmember(gid, cr)) 306 return (0); 307 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 308 return (0); 309 return (spl_priv_check_cred(cr, PRIV_VFS_SETGID)); 310 } 311 312 int 313 secpolicy_vnode_setid_retain(znode_t *zp, cred_t *cr, 314 boolean_t issuidroot __unused) 315 { 316 317 if (secpolicy_fs_owner(ZTOV(zp)->v_mount, cr) == 0) 318 return (0); 319 return (spl_priv_check_cred(cr, PRIV_VFS_RETAINSUGID)); 320 } 321 322 void 323 secpolicy_setid_clear(struct vattr *vap, vnode_t *vp, cred_t *cr) 324 { 325 326 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 327 return; 328 329 if ((vap->va_mode & (S_ISUID | S_ISGID)) != 0) { 330 if (spl_priv_check_cred(cr, PRIV_VFS_RETAINSUGID)) { 331 vap->va_mask |= AT_MODE; 332 vap->va_mode &= ~(S_ISUID|S_ISGID); 333 } 334 } 335 } 336 337 int 338 secpolicy_setid_setsticky_clear(vnode_t *vp, struct vattr *vap, 339 const struct vattr *ovap, cred_t *cr) 340 { 341 int error; 342 343 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 344 return (0); 345 346 /* 347 * Privileged processes may set the sticky bit on non-directories, 348 * as well as set the setgid bit on a file with a group that the process 349 * is not a member of. Both of these are allowed in jail(8). 350 */ 351 if (vp->v_type != VDIR && (vap->va_mode & S_ISTXT)) { 352 if (spl_priv_check_cred(cr, PRIV_VFS_STICKYFILE)) 353 return (EFTYPE); 354 } 355 /* 356 * Check for privilege if attempting to set the 357 * group-id bit. 358 */ 359 if ((vap->va_mode & S_ISGID) != 0) { 360 error = secpolicy_vnode_setids_setgids(vp, cr, ovap->va_gid); 361 if (error) 362 return (error); 363 } 364 /* 365 * Deny setting setuid if we are not the file owner. 366 */ 367 if ((vap->va_mode & S_ISUID) && ovap->va_uid != cr->cr_uid) { 368 error = spl_priv_check_cred(cr, PRIV_VFS_ADMIN); 369 if (error) 370 return (error); 371 } 372 return (0); 373 } 374 375 int 376 secpolicy_fs_mount(cred_t *cr, vnode_t *mvp, struct mount *vfsp) 377 { 378 379 return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT)); 380 } 381 382 int 383 secpolicy_vnode_owner(vnode_t *vp, cred_t *cr, uid_t owner) 384 { 385 386 if (owner == cr->cr_uid) 387 return (0); 388 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 389 return (0); 390 391 /* XXX: vfs_suser()? */ 392 return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT_OWNER)); 393 } 394 395 int 396 secpolicy_vnode_chown(vnode_t *vp, cred_t *cr, uid_t owner) 397 { 398 399 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 400 return (0); 401 return (spl_priv_check_cred(cr, PRIV_VFS_CHOWN)); 402 } 403 404 void 405 secpolicy_fs_mount_clearopts(cred_t *cr, struct mount *vfsp) 406 { 407 408 if (spl_priv_check_cred(cr, PRIV_VFS_MOUNT_NONUSER) != 0) { 409 MNT_ILOCK(vfsp); 410 vfsp->vfs_flag |= VFS_NOSETUID | MNT_USER; 411 vfs_clearmntopt(vfsp, MNTOPT_SETUID); 412 vfs_setmntopt(vfsp, MNTOPT_NOSETUID, NULL, 0); 413 MNT_IUNLOCK(vfsp); 414 } 415 } 416 417 /* 418 * Check privileges for setting xvattr attributes 419 */ 420 int 421 secpolicy_xvattr(vnode_t *vp, xvattr_t *xvap, uid_t owner, cred_t *cr, 422 vtype_t vtype) 423 { 424 425 if (secpolicy_fs_owner(vp->v_mount, cr) == 0) 426 return (0); 427 return (spl_priv_check_cred(cr, PRIV_VFS_SYSFLAGS)); 428 } 429 430 int 431 secpolicy_smb(cred_t *cr) 432 { 433 434 return (spl_priv_check_cred(cr, PRIV_NETSMB)); 435 } 436