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