1 /* 2 * Copyright (c) 2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * nlookup() is the 'new' namei interface. Rather then return directory and 36 * leaf vnodes (in various lock states) the new interface instead deals in 37 * namecache records. Namecache records may represent both a positive or 38 * a negative hit. The namespace is locked via the namecache record instead 39 * of via the vnode, and only the leaf namecache record (representing the 40 * filename) needs to be locked. 41 * 42 * This greatly improves filesystem parallelism and is a huge simplification 43 * of the API verses the old vnode locking / namei scheme. 44 * 45 * Filesystems must actively control the caching aspects of the namecache, 46 * and since namecache pointers are used as handles they are non-optional 47 * even for filesystems which do not generally wish to cache things. It is 48 * intended that a separate cache coherency API will be constructed to handle 49 * these issues. 50 */ 51 52 #include "opt_ktrace.h" 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/kernel.h> 57 #include <sys/vnode.h> 58 #include <sys/mount.h> 59 #include <sys/filedesc.h> 60 #include <sys/proc.h> 61 #include <sys/namei.h> 62 #include <sys/nlookup.h> 63 #include <sys/malloc.h> 64 #include <sys/stat.h> 65 #include <sys/objcache.h> 66 #include <sys/file.h> 67 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 72 static int naccess(struct nchandle *nch, int vmode, struct ucred *cred, 73 int *stickyp); 74 75 /* 76 * Initialize a nlookup() structure, early error return for copyin faults 77 * or a degenerate empty string (which is not allowed). 78 * 79 * The first process proc0's credentials are used if the calling thread 80 * is not associated with a process context. 81 * 82 * MPSAFE 83 */ 84 int 85 nlookup_init(struct nlookupdata *nd, 86 const char *path, enum uio_seg seg, int flags) 87 { 88 size_t pathlen; 89 struct proc *p; 90 thread_t td; 91 int error; 92 93 td = curthread; 94 p = td->td_proc; 95 96 /* 97 * note: the pathlen set by copy*str() includes the terminating \0. 98 */ 99 bzero(nd, sizeof(struct nlookupdata)); 100 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 101 nd->nl_flags |= NLC_HASBUF; 102 if (seg == UIO_SYSSPACE) 103 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 104 else 105 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 106 107 /* 108 * Don't allow empty pathnames. 109 * POSIX.1 requirement: "" is not a vaild file name. 110 */ 111 if (error == 0 && pathlen <= 1) 112 error = ENOENT; 113 114 if (error == 0) { 115 if (p && p->p_fd) { 116 cache_copy(&p->p_fd->fd_ncdir, &nd->nl_nch); 117 cache_copy(&p->p_fd->fd_nrdir, &nd->nl_rootnch); 118 if (p->p_fd->fd_njdir.ncp) 119 cache_copy(&p->p_fd->fd_njdir, &nd->nl_jailnch); 120 nd->nl_cred = crhold(p->p_ucred); 121 } else { 122 cache_copy(&rootnch, &nd->nl_nch); 123 cache_copy(&nd->nl_nch, &nd->nl_rootnch); 124 cache_copy(&nd->nl_nch, &nd->nl_jailnch); 125 nd->nl_cred = crhold(proc0.p_ucred); 126 } 127 nd->nl_td = td; 128 nd->nl_flags |= flags; 129 } else { 130 nlookup_done(nd); 131 } 132 return(error); 133 } 134 135 136 /* 137 * nlookup_init() for "at" family of syscalls. 138 * 139 * Works similarly to nlookup_init() but if path is relative and fd is not 140 * AT_FDCWD, path is interpreted relative to the directory pointed to by fd. 141 * In this case, the file entry pointed to by fd is ref'ed and returned in 142 * *fpp. 143 * 144 * If the call succeeds, nlookup_done_at() must be called to clean-up the nd 145 * and release the ref to the file entry. 146 */ 147 int 148 nlookup_init_at(struct nlookupdata *nd, struct file **fpp, int fd, 149 const char *path, enum uio_seg seg, int flags) 150 { 151 struct thread *td = curthread; 152 struct proc *p = td->td_proc; 153 struct file* fp; 154 struct vnode *vp; 155 int error; 156 157 *fpp = NULL; 158 159 if ((error = nlookup_init(nd, path, seg, flags)) != 0) { 160 return (error); 161 } 162 163 if (nd->nl_path[0] != '/' && fd != AT_FDCWD) { 164 if ((error = holdvnode(p->p_fd, fd, &fp)) != 0) 165 goto done; 166 vp = (struct vnode*)fp->f_data; 167 if (vp->v_type != VDIR || fp->f_nchandle.ncp == NULL) { 168 fdrop(fp); 169 fp = NULL; 170 error = ENOTDIR; 171 goto done; 172 } 173 cache_drop(&nd->nl_nch); 174 cache_copy(&fp->f_nchandle, &nd->nl_nch); 175 *fpp = fp; 176 } 177 178 179 done: 180 if (error) 181 nlookup_done(nd); 182 return (error); 183 184 } 185 186 /* 187 * This works similarly to nlookup_init() but does not assume a process 188 * context. rootnch is always chosen for the root directory and the cred 189 * and starting directory are supplied in arguments. 190 */ 191 int 192 nlookup_init_raw(struct nlookupdata *nd, 193 const char *path, enum uio_seg seg, int flags, 194 struct ucred *cred, struct nchandle *ncstart) 195 { 196 size_t pathlen; 197 thread_t td; 198 int error; 199 200 td = curthread; 201 202 bzero(nd, sizeof(struct nlookupdata)); 203 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 204 nd->nl_flags |= NLC_HASBUF; 205 if (seg == UIO_SYSSPACE) 206 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 207 else 208 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 209 210 /* 211 * Don't allow empty pathnames. 212 * POSIX.1 requirement: "" is not a vaild file name. 213 */ 214 if (error == 0 && pathlen <= 1) 215 error = ENOENT; 216 217 if (error == 0) { 218 cache_copy(ncstart, &nd->nl_nch); 219 cache_copy(&rootnch, &nd->nl_rootnch); 220 cache_copy(&rootnch, &nd->nl_jailnch); 221 nd->nl_cred = crhold(cred); 222 nd->nl_td = td; 223 nd->nl_flags |= flags; 224 } else { 225 nlookup_done(nd); 226 } 227 return(error); 228 } 229 230 /* 231 * This works similarly to nlookup_init_raw() but does not rely 232 * on rootnch being initialized yet. 233 */ 234 int 235 nlookup_init_root(struct nlookupdata *nd, 236 const char *path, enum uio_seg seg, int flags, 237 struct ucred *cred, struct nchandle *ncstart, 238 struct nchandle *ncroot) 239 { 240 size_t pathlen; 241 thread_t td; 242 int error; 243 244 td = curthread; 245 246 bzero(nd, sizeof(struct nlookupdata)); 247 nd->nl_path = objcache_get(namei_oc, M_WAITOK); 248 nd->nl_flags |= NLC_HASBUF; 249 if (seg == UIO_SYSSPACE) 250 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen); 251 else 252 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen); 253 254 /* 255 * Don't allow empty pathnames. 256 * POSIX.1 requirement: "" is not a vaild file name. 257 */ 258 if (error == 0 && pathlen <= 1) 259 error = ENOENT; 260 261 if (error == 0) { 262 cache_copy(ncstart, &nd->nl_nch); 263 cache_copy(ncroot, &nd->nl_rootnch); 264 cache_copy(ncroot, &nd->nl_jailnch); 265 nd->nl_cred = crhold(cred); 266 nd->nl_td = td; 267 nd->nl_flags |= flags; 268 } else { 269 nlookup_done(nd); 270 } 271 return(error); 272 } 273 274 /* 275 * Set a different credential; this credential will be used by future 276 * operations performed on nd.nl_open_vp and nlookupdata structure. 277 */ 278 void 279 nlookup_set_cred(struct nlookupdata *nd, struct ucred *cred) 280 { 281 KKASSERT(nd->nl_cred != NULL); 282 283 if (nd->nl_cred != cred) { 284 cred = crhold(cred); 285 crfree(nd->nl_cred); 286 nd->nl_cred = cred; 287 } 288 } 289 290 /* 291 * Cleanup a nlookupdata structure after we are through with it. This may 292 * be called on any nlookupdata structure initialized with nlookup_init(). 293 * Calling nlookup_done() is mandatory in all cases except where nlookup_init() 294 * returns an error, even if as a consumer you believe you have taken all 295 * dynamic elements out of the nlookupdata structure. 296 */ 297 void 298 nlookup_done(struct nlookupdata *nd) 299 { 300 if (nd->nl_nch.ncp) { 301 if (nd->nl_flags & NLC_NCPISLOCKED) { 302 nd->nl_flags &= ~NLC_NCPISLOCKED; 303 cache_unlock(&nd->nl_nch); 304 } 305 cache_drop(&nd->nl_nch); /* NULL's out the nch */ 306 } 307 if (nd->nl_rootnch.ncp) 308 cache_drop(&nd->nl_rootnch); 309 if (nd->nl_jailnch.ncp) 310 cache_drop(&nd->nl_jailnch); 311 if ((nd->nl_flags & NLC_HASBUF) && nd->nl_path) { 312 objcache_put(namei_oc, nd->nl_path); 313 nd->nl_path = NULL; 314 } 315 if (nd->nl_cred) { 316 crfree(nd->nl_cred); 317 nd->nl_cred = NULL; 318 } 319 if (nd->nl_open_vp) { 320 if (nd->nl_flags & NLC_LOCKVP) { 321 vn_unlock(nd->nl_open_vp); 322 nd->nl_flags &= ~NLC_LOCKVP; 323 } 324 vn_close(nd->nl_open_vp, nd->nl_vp_fmode, NULL); 325 nd->nl_open_vp = NULL; 326 } 327 if (nd->nl_dvp) { 328 vrele(nd->nl_dvp); 329 nd->nl_dvp = NULL; 330 } 331 nd->nl_flags = 0; /* clear remaining flags (just clear everything) */ 332 } 333 334 /* 335 * Works similarly to nlookup_done() when nd initialized with 336 * nlookup_init_at(). 337 */ 338 void 339 nlookup_done_at(struct nlookupdata *nd, struct file *fp) 340 { 341 nlookup_done(nd); 342 if (fp != NULL) 343 fdrop(fp); 344 } 345 346 void 347 nlookup_zero(struct nlookupdata *nd) 348 { 349 bzero(nd, sizeof(struct nlookupdata)); 350 } 351 352 /* 353 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL 354 * if an error occured. 355 * 356 * Note that the returned ncp is not checked for permissions, though VEXEC 357 * is checked on the directory path leading up to the result. The caller 358 * must call naccess() to check the permissions of the returned leaf. 359 */ 360 struct nchandle 361 nlookup_simple(const char *str, enum uio_seg seg, 362 int niflags, int *error) 363 { 364 struct nlookupdata nd; 365 struct nchandle nch; 366 367 *error = nlookup_init(&nd, str, seg, niflags); 368 if (*error == 0) { 369 if ((*error = nlookup(&nd)) == 0) { 370 nch = nd.nl_nch; /* keep hold ref from structure */ 371 cache_zero(&nd.nl_nch); /* and NULL out */ 372 } else { 373 cache_zero(&nch); 374 } 375 nlookup_done(&nd); 376 } else { 377 cache_zero(&nch); 378 } 379 return(nch); 380 } 381 382 /* 383 * Returns non-zero if the path element is the last element 384 */ 385 static 386 int 387 islastelement(const char *ptr) 388 { 389 while (*ptr == '/') 390 ++ptr; 391 return (*ptr == 0); 392 } 393 394 /* 395 * Returns non-zero if we need to lock the namecache element 396 * exclusively. Unless otherwise requested by NLC_SHAREDLOCK, 397 * the last element of the namecache lookup will be locked 398 * exclusively. 399 * 400 * NOTE: Even if we return on-zero, an unresolved namecache record 401 * will always be locked exclusively. 402 */ 403 static __inline 404 int 405 wantsexcllock(struct nlookupdata *nd, const char *ptr) 406 { 407 if ((nd->nl_flags & NLC_SHAREDLOCK) == 0) 408 return(islastelement(ptr)); 409 return(0); 410 } 411 412 413 /* 414 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d 415 * on return, even if an error occurs. If no error occurs or NLC_CREATE 416 * is flagged and ENOENT is returned, then the returned nl_nch is always 417 * referenced and locked exclusively. 418 * 419 * WARNING: For any general error other than ENOENT w/NLC_CREATE, the 420 * the resulting nl_nch may or may not be locked and if locked 421 * might be locked either shared or exclusive. 422 * 423 * Intermediate directory elements, including the current directory, require 424 * execute (search) permission. nlookup does not examine the access 425 * permissions on the returned element. 426 * 427 * If NLC_CREATE is set the last directory must allow node creation, 428 * and an error code of 0 will be returned for a non-existant 429 * target (not ENOENT). 430 * 431 * If NLC_RENAME_DST is set the last directory mut allow node deletion, 432 * plus the sticky check is made, and an error code of 0 will be returned 433 * for a non-existant target (not ENOENT). 434 * 435 * If NLC_DELETE is set the last directory mut allow node deletion, 436 * plus the sticky check is made. 437 * 438 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode 439 * of the returned entry. The vnode will be referenced, but not locked, 440 * and will be released by nlookup_done() along with everything else. 441 * 442 * NOTE: As an optimization we attempt to obtain a shared namecache lock 443 * on any intermediate elements. On success, the returned element 444 * is ALWAYS locked exclusively. 445 */ 446 int 447 nlookup(struct nlookupdata *nd) 448 { 449 globaldata_t gd = mycpu; 450 struct nlcomponent nlc; 451 struct nchandle nch; 452 struct nchandle par; 453 struct nchandle nctmp; 454 struct mount *mp; 455 struct vnode *hvp; /* hold to prevent recyclement */ 456 int wasdotordotdot; 457 char *ptr; 458 int error; 459 int len; 460 int dflags; 461 int hit = 1; 462 int saveflag = nd->nl_flags; 463 boolean_t doretry = FALSE; 464 boolean_t inretry = FALSE; 465 466 nlookup_start: 467 #ifdef KTRACE 468 if (KTRPOINT(nd->nl_td, KTR_NAMEI)) 469 ktrnamei(nd->nl_td->td_lwp, nd->nl_path); 470 #endif 471 bzero(&nlc, sizeof(nlc)); 472 473 /* 474 * Setup for the loop. The current working namecache element is 475 * always at least referenced. We lock it as required, but always 476 * return a locked, resolved namecache entry. 477 */ 478 nd->nl_loopcnt = 0; 479 if (nd->nl_dvp) { 480 vrele(nd->nl_dvp); 481 nd->nl_dvp = NULL; 482 } 483 ptr = nd->nl_path; 484 485 /* 486 * Loop on the path components. At the top of the loop nd->nl_nch 487 * is ref'd and unlocked and represents our current position. 488 */ 489 for (;;) { 490 /* 491 * Make sure nl_nch is locked so we can access the vnode, resolution 492 * state, etc. 493 */ 494 if ((nd->nl_flags & NLC_NCPISLOCKED) == 0) { 495 nd->nl_flags |= NLC_NCPISLOCKED; 496 cache_lock_maybe_shared(&nd->nl_nch, wantsexcllock(nd, ptr)); 497 } 498 499 /* 500 * Check if the root directory should replace the current 501 * directory. This is done at the start of a translation 502 * or after a symbolic link has been found. In other cases 503 * ptr will never be pointing at a '/'. 504 */ 505 if (*ptr == '/') { 506 do { 507 ++ptr; 508 } while (*ptr == '/'); 509 cache_unlock(&nd->nl_nch); 510 cache_get_maybe_shared(&nd->nl_rootnch, &nch, 511 wantsexcllock(nd, ptr)); 512 cache_drop(&nd->nl_nch); 513 nd->nl_nch = nch; /* remains locked */ 514 515 /* 516 * Fast-track termination. There is no parent directory of 517 * the root in the same mount from the point of view of 518 * the caller so return EACCES if NLC_REFDVP is specified, 519 * and EEXIST if NLC_CREATE is also specified. 520 * e.g. 'rmdir /' or 'mkdir /' are not allowed. 521 */ 522 if (*ptr == 0) { 523 if (nd->nl_flags & NLC_REFDVP) 524 error = (nd->nl_flags & NLC_CREATE) ? EEXIST : EACCES; 525 else 526 error = 0; 527 break; 528 } 529 continue; 530 } 531 532 /* 533 * Check directory search permissions (nd->nl_nch is locked & refd) 534 */ 535 dflags = 0; 536 error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, &dflags); 537 if (error) 538 break; 539 540 /* 541 * Extract the path component. Path components are limited to 542 * 255 characters. 543 */ 544 nlc.nlc_nameptr = ptr; 545 while (*ptr && *ptr != '/') 546 ++ptr; 547 nlc.nlc_namelen = ptr - nlc.nlc_nameptr; 548 if (nlc.nlc_namelen >= 256) { 549 error = ENAMETOOLONG; 550 break; 551 } 552 553 /* 554 * Lookup the path component in the cache, creating an unresolved 555 * entry if necessary. We have to handle "." and ".." as special 556 * cases. 557 * 558 * When handling ".." we have to detect a traversal back through a 559 * mount point. If we are at the root, ".." just returns the root. 560 * 561 * When handling "." or ".." we also have to recalculate dflags 562 * since our dflags will be for some sub-directory instead of the 563 * parent dir. 564 * 565 * This subsection returns a locked, refd 'nch' unless it errors out, 566 * and an unlocked but still ref'd nd->nl_nch. 567 * 568 * The namecache topology is not allowed to be disconnected, so 569 * encountering a NULL parent will generate EINVAL. This typically 570 * occurs when a directory is removed out from under a process. 571 * 572 * WARNING! The unlocking of nd->nl_nch is sensitive code. 573 */ 574 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED); 575 576 if (nlc.nlc_namelen == 1 && nlc.nlc_nameptr[0] == '.') { 577 cache_unlock(&nd->nl_nch); 578 nd->nl_flags &= ~NLC_NCPISLOCKED; 579 cache_get_maybe_shared(&nd->nl_nch, &nch, wantsexcllock(nd, ptr)); 580 wasdotordotdot = 1; 581 } else if (nlc.nlc_namelen == 2 && 582 nlc.nlc_nameptr[0] == '.' && nlc.nlc_nameptr[1] == '.') { 583 if (nd->nl_nch.mount == nd->nl_rootnch.mount && 584 nd->nl_nch.ncp == nd->nl_rootnch.ncp 585 ) { 586 /* 587 * ".." at the root returns the root 588 */ 589 cache_unlock(&nd->nl_nch); 590 nd->nl_flags &= ~NLC_NCPISLOCKED; 591 cache_get_maybe_shared(&nd->nl_nch, &nch, 592 wantsexcllock(nd, ptr)); 593 } else { 594 /* 595 * Locate the parent ncp. If we are at the root of a 596 * filesystem mount we have to skip to the mounted-on 597 * point in the underlying filesystem. 598 * 599 * Expect the parent to always be good since the 600 * mountpoint doesn't go away. XXX hack. cache_get() 601 * requires the ncp to already have a ref as a safety. 602 * 603 * However, a process which has been broken out of a chroot 604 * will wind up with a NULL parent if it tries to '..' above 605 * the real root, deal with the case. Note that this does 606 * not protect us from a jail breakout, it just stops a panic 607 * if the jail-broken process tries to '..' past the real 608 * root. 609 */ 610 nctmp = nd->nl_nch; 611 while (nctmp.ncp == nctmp.mount->mnt_ncmountpt.ncp) { 612 nctmp = nctmp.mount->mnt_ncmounton; 613 if (nctmp.ncp == NULL) 614 break; 615 } 616 if (nctmp.ncp == NULL) { 617 if (curthread->td_proc) { 618 kprintf("vfs_nlookup: '..' traverse broke " 619 "jail: pid %d (%s)\n", 620 curthread->td_proc->p_pid, 621 curthread->td_comm); 622 } 623 nctmp = nd->nl_rootnch; 624 } else { 625 nctmp.ncp = nctmp.ncp->nc_parent; 626 } 627 cache_hold(&nctmp); 628 cache_unlock(&nd->nl_nch); 629 nd->nl_flags &= ~NLC_NCPISLOCKED; 630 cache_get_maybe_shared(&nctmp, &nch, wantsexcllock(nd, ptr)); 631 cache_drop(&nctmp); /* NOTE: zero's nctmp */ 632 } 633 wasdotordotdot = 2; 634 } else { 635 /* 636 * Must unlock nl_nch when traversing down the path. However, 637 * the child ncp has not yet been found/created and the parent's 638 * child list might be empty. Thus releasing the lock can 639 * allow a race whereby the parent ncp's vnode is recycled. 640 * This case can occur especially when maxvnodes is set very low. 641 * 642 * We need the parent's ncp to remain resolved for all normal 643 * filesystem activities, so we vhold() the vp during the lookup 644 * to prevent recyclement due to vnlru / maxvnodes. 645 * 646 * If we race an unlink or rename the ncp might be marked 647 * DESTROYED after resolution, requiring a retry. 648 */ 649 if ((hvp = nd->nl_nch.ncp->nc_vp) != NULL) 650 vhold(hvp); 651 cache_unlock(&nd->nl_nch); 652 nd->nl_flags &= ~NLC_NCPISLOCKED; 653 error = cache_nlookup_maybe_shared(&nd->nl_nch, &nlc, 654 wantsexcllock(nd, ptr), &nch); 655 if (error == EWOULDBLOCK) { 656 nch = cache_nlookup(&nd->nl_nch, &nlc); 657 if (nch.ncp->nc_flag & NCF_UNRESOLVED) 658 hit = 0; 659 for (;;) { 660 error = cache_resolve(&nch, nd->nl_cred); 661 if (error != EAGAIN && 662 (nch.ncp->nc_flag & NCF_DESTROYED) == 0) { 663 if (error == ESTALE) { 664 if (!inretry) 665 error = ENOENT; 666 doretry = TRUE; 667 } 668 break; 669 } 670 kprintf("[diagnostic] nlookup: relookup %*.*s\n", 671 nch.ncp->nc_nlen, nch.ncp->nc_nlen, 672 nch.ncp->nc_name); 673 cache_put(&nch); 674 nch = cache_nlookup(&nd->nl_nch, &nlc); 675 } 676 } 677 if (hvp) 678 vdrop(hvp); 679 wasdotordotdot = 0; 680 } 681 682 /* 683 * If the last component was "." or ".." our dflags no longer 684 * represents the parent directory and we have to explicitly 685 * look it up. 686 * 687 * Expect the parent to be good since nch is locked. 688 */ 689 if (wasdotordotdot && error == 0) { 690 dflags = 0; 691 if ((par.ncp = nch.ncp->nc_parent) != NULL) { 692 par.mount = nch.mount; 693 cache_hold(&par); 694 cache_lock_maybe_shared(&par, wantsexcllock(nd, ptr)); 695 error = naccess(&par, 0, nd->nl_cred, &dflags); 696 cache_put(&par); 697 } 698 } 699 700 /* 701 * [end of subsection] 702 * 703 * nch is locked and referenced. 704 * nd->nl_nch is unlocked and referenced. 705 * 706 * nl_nch must be unlocked or we could chain lock to the root 707 * if a resolve gets stuck (e.g. in NFS). 708 */ 709 KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0); 710 711 /* 712 * Resolve the namespace if necessary. The ncp returned by 713 * cache_nlookup() is referenced and locked. 714 * 715 * XXX neither '.' nor '..' should return EAGAIN since they were 716 * previously resolved and thus cannot be newly created ncp's. 717 */ 718 if (nch.ncp->nc_flag & NCF_UNRESOLVED) { 719 hit = 0; 720 error = cache_resolve(&nch, nd->nl_cred); 721 if (error == ESTALE) { 722 if (!inretry) 723 error = ENOENT; 724 doretry = TRUE; 725 } 726 KKASSERT(error != EAGAIN); 727 } else { 728 error = nch.ncp->nc_error; 729 } 730 731 /* 732 * Early completion. ENOENT is not an error if this is the last 733 * component and NLC_CREATE or NLC_RENAME (rename target) was 734 * requested. Note that ncp->nc_error is left as ENOENT in that 735 * case, which we check later on. 736 * 737 * Also handle invalid '.' or '..' components terminating a path 738 * for a create/rename/delete. The standard requires this and pax 739 * pretty stupidly depends on it. 740 */ 741 if (islastelement(ptr)) { 742 if (error == ENOENT && 743 (nd->nl_flags & (NLC_CREATE | NLC_RENAME_DST)) 744 ) { 745 if (nd->nl_flags & NLC_NFS_RDONLY) { 746 error = EROFS; 747 } else { 748 error = naccess(&nch, nd->nl_flags | dflags, 749 nd->nl_cred, NULL); 750 } 751 } 752 if (error == 0 && wasdotordotdot && 753 (nd->nl_flags & (NLC_CREATE | NLC_DELETE | 754 NLC_RENAME_SRC | NLC_RENAME_DST))) { 755 /* 756 * POSIX junk 757 */ 758 if (nd->nl_flags & NLC_CREATE) 759 error = EEXIST; 760 else if (nd->nl_flags & NLC_DELETE) 761 error = (wasdotordotdot == 1) ? EINVAL : ENOTEMPTY; 762 else 763 error = EINVAL; 764 } 765 } 766 767 /* 768 * Early completion on error. 769 */ 770 if (error) { 771 cache_put(&nch); 772 break; 773 } 774 775 /* 776 * If the element is a symlink and it is either not the last 777 * element or it is the last element and we are allowed to 778 * follow symlinks, resolve the symlink. 779 */ 780 if ((nch.ncp->nc_flag & NCF_ISSYMLINK) && 781 (*ptr || (nd->nl_flags & NLC_FOLLOW)) 782 ) { 783 if (nd->nl_loopcnt++ >= MAXSYMLINKS) { 784 error = ELOOP; 785 cache_put(&nch); 786 break; 787 } 788 error = nreadsymlink(nd, &nch, &nlc); 789 cache_put(&nch); 790 if (error) 791 break; 792 793 /* 794 * Concatenate trailing path elements onto the returned symlink. 795 * Note that if the path component (ptr) is not exhausted, it 796 * will being with a '/', so we do not have to add another one. 797 * 798 * The symlink may not be empty. 799 */ 800 len = strlen(ptr); 801 if (nlc.nlc_namelen == 0 || nlc.nlc_namelen + len >= MAXPATHLEN) { 802 error = nlc.nlc_namelen ? ENAMETOOLONG : ENOENT; 803 objcache_put(namei_oc, nlc.nlc_nameptr); 804 break; 805 } 806 bcopy(ptr, nlc.nlc_nameptr + nlc.nlc_namelen, len + 1); 807 if (nd->nl_flags & NLC_HASBUF) 808 objcache_put(namei_oc, nd->nl_path); 809 nd->nl_path = nlc.nlc_nameptr; 810 nd->nl_flags |= NLC_HASBUF; 811 ptr = nd->nl_path; 812 813 /* 814 * Go back up to the top to resolve any initial '/'s in the 815 * symlink. 816 */ 817 continue; 818 } 819 820 /* 821 * If the element is a directory and we are crossing a mount point, 822 * Locate the mount. 823 */ 824 while ((nch.ncp->nc_flag & NCF_ISMOUNTPT) && 825 (nd->nl_flags & NLC_NOCROSSMOUNT) == 0 && 826 (mp = cache_findmount(&nch)) != NULL 827 ) { 828 struct vnode *tdp; 829 int vfs_do_busy = 0; 830 831 /* 832 * VFS must be busied before the namecache entry is locked, 833 * but we don't want to waste time calling vfs_busy() if the 834 * mount point is already resolved. 835 */ 836 again: 837 cache_put(&nch); 838 if (vfs_do_busy) { 839 while (vfs_busy(mp, 0)) { 840 if (mp->mnt_kern_flag & MNTK_UNMOUNT) { 841 kprintf("nlookup: warning umount race avoided\n"); 842 cache_dropmount(mp); 843 error = EBUSY; 844 vfs_do_busy = 0; 845 goto double_break; 846 } 847 } 848 } 849 cache_get_maybe_shared(&mp->mnt_ncmountpt, &nch, 850 wantsexcllock(nd, ptr)); 851 852 if (nch.ncp->nc_flag & NCF_UNRESOLVED) { 853 if (vfs_do_busy == 0) { 854 vfs_do_busy = 1; 855 goto again; 856 } 857 error = VFS_ROOT(mp, &tdp); 858 vfs_unbusy(mp); 859 vfs_do_busy = 0; 860 if (error) { 861 cache_dropmount(mp); 862 break; 863 } 864 cache_setvp(&nch, tdp); 865 vput(tdp); 866 } 867 if (vfs_do_busy) 868 vfs_unbusy(mp); 869 cache_dropmount(mp); 870 } 871 872 if (error) { 873 cache_put(&nch); 874 double_break: 875 break; 876 } 877 878 /* 879 * Skip any slashes to get to the next element. If there 880 * are any slashes at all the current element must be a 881 * directory or, in the create case, intended to become a directory. 882 * If it isn't we break without incrementing ptr and fall through 883 * to the failure case below. 884 */ 885 while (*ptr == '/') { 886 if ((nch.ncp->nc_flag & NCF_ISDIR) == 0 && 887 !(nd->nl_flags & NLC_WILLBEDIR) 888 ) { 889 break; 890 } 891 ++ptr; 892 } 893 894 /* 895 * Continuation case: additional elements and the current 896 * element is a directory. 897 */ 898 if (*ptr && (nch.ncp->nc_flag & NCF_ISDIR)) { 899 cache_drop(&nd->nl_nch); 900 cache_unlock(&nch); 901 KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0); 902 nd->nl_nch = nch; 903 continue; 904 } 905 906 /* 907 * Failure case: additional elements and the current element 908 * is not a directory 909 */ 910 if (*ptr) { 911 cache_put(&nch); 912 error = ENOTDIR; 913 break; 914 } 915 916 /* 917 * Successful lookup of last element. 918 * 919 * Check permissions if the target exists. If the target does not 920 * exist directory permissions were already tested in the early 921 * completion code above. 922 * 923 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY 924 * if the file is marked append-only, and NLC_STICKY if the directory 925 * containing the file is sticky. 926 */ 927 if (nch.ncp->nc_vp && (nd->nl_flags & NLC_ALLCHKS)) { 928 error = naccess(&nch, nd->nl_flags | dflags, 929 nd->nl_cred, NULL); 930 if (error) { 931 cache_put(&nch); 932 break; 933 } 934 } 935 936 /* 937 * Termination: no more elements. 938 * 939 * If NLC_REFDVP is set acquire a referenced parent dvp. 940 */ 941 if (nd->nl_flags & NLC_REFDVP) { 942 cache_lock(&nd->nl_nch); 943 error = cache_vref(&nd->nl_nch, nd->nl_cred, &nd->nl_dvp); 944 cache_unlock(&nd->nl_nch); 945 if (error) { 946 kprintf("NLC_REFDVP: Cannot ref dvp of %p\n", nch.ncp); 947 cache_put(&nch); 948 break; 949 } 950 } 951 cache_drop(&nd->nl_nch); 952 nd->nl_nch = nch; 953 nd->nl_flags |= NLC_NCPISLOCKED; 954 error = 0; 955 break; 956 } 957 958 if (hit) 959 ++gd->gd_nchstats->ncs_longhits; 960 else 961 ++gd->gd_nchstats->ncs_longmiss; 962 963 if (nd->nl_flags & NLC_NCPISLOCKED) 964 KKASSERT(cache_lockstatus(&nd->nl_nch) > 0); 965 966 /* 967 * Retry the whole thing if doretry flag is set, but only once. 968 * autofs(5) may mount another filesystem under its root directory 969 * while resolving a path. 970 */ 971 if (doretry && !inretry) { 972 inretry = TRUE; 973 nd->nl_flags = saveflag; 974 goto nlookup_start; 975 } 976 977 /* 978 * NOTE: If NLC_CREATE was set the ncp may represent a negative hit 979 * (ncp->nc_error will be ENOENT), but we will still return an error 980 * code of 0. 981 */ 982 return(error); 983 } 984 985 /* 986 * Resolve a mount point's glue ncp. This ncp connects creates the illusion 987 * of continuity in the namecache tree by connecting the ncp related to the 988 * vnode under the mount to the ncp related to the mount's root vnode. 989 * 990 * If no error occured a locked, ref'd ncp is stored in *ncpp. 991 */ 992 int 993 nlookup_mp(struct mount *mp, struct nchandle *nch) 994 { 995 struct vnode *vp; 996 int error; 997 998 error = 0; 999 cache_get(&mp->mnt_ncmountpt, nch); 1000 if (nch->ncp->nc_flag & NCF_UNRESOLVED) { 1001 while (vfs_busy(mp, 0)) 1002 ; 1003 error = VFS_ROOT(mp, &vp); 1004 vfs_unbusy(mp); 1005 if (error) { 1006 cache_put(nch); 1007 } else { 1008 cache_setvp(nch, vp); 1009 vput(vp); 1010 } 1011 } 1012 return(error); 1013 } 1014 1015 /* 1016 * Read the contents of a symlink, allocate a path buffer out of the 1017 * namei_oc and initialize the supplied nlcomponent with the result. 1018 * 1019 * If an error occurs no buffer will be allocated or returned in the nlc. 1020 */ 1021 int 1022 nreadsymlink(struct nlookupdata *nd, struct nchandle *nch, 1023 struct nlcomponent *nlc) 1024 { 1025 struct vnode *vp; 1026 struct iovec aiov; 1027 struct uio auio; 1028 int linklen; 1029 int error; 1030 char *cp; 1031 1032 nlc->nlc_nameptr = NULL; 1033 nlc->nlc_namelen = 0; 1034 if (nch->ncp->nc_vp == NULL) 1035 return(ENOENT); 1036 if ((error = cache_vget(nch, nd->nl_cred, LK_SHARED, &vp)) != 0) 1037 return(error); 1038 cp = objcache_get(namei_oc, M_WAITOK); 1039 aiov.iov_base = cp; 1040 aiov.iov_len = MAXPATHLEN; 1041 auio.uio_iov = &aiov; 1042 auio.uio_iovcnt = 1; 1043 auio.uio_offset = 0; 1044 auio.uio_rw = UIO_READ; 1045 auio.uio_segflg = UIO_SYSSPACE; 1046 auio.uio_td = nd->nl_td; 1047 auio.uio_resid = MAXPATHLEN - 1; 1048 error = VOP_READLINK(vp, &auio, nd->nl_cred); 1049 if (error) 1050 goto fail; 1051 linklen = MAXPATHLEN - 1 - auio.uio_resid; 1052 if (varsym_enable) { 1053 linklen = varsymreplace(cp, linklen, MAXPATHLEN - 1); 1054 if (linklen < 0) { 1055 error = ENAMETOOLONG; 1056 goto fail; 1057 } 1058 } 1059 cp[linklen] = 0; 1060 nlc->nlc_nameptr = cp; 1061 nlc->nlc_namelen = linklen; 1062 vput(vp); 1063 return(0); 1064 fail: 1065 objcache_put(namei_oc, cp); 1066 vput(vp); 1067 return(error); 1068 } 1069 1070 /* 1071 * Check access [XXX cache vattr!] [XXX quota] 1072 * 1073 * Generally check the NLC_* access bits. All specified bits must pass 1074 * for this function to return 0. 1075 * 1076 * The file does not have to exist when checking NLC_CREATE or NLC_RENAME_DST 1077 * access, otherwise it must exist. No error is returned in this case. 1078 * 1079 * The file must not exist if NLC_EXCL is specified. 1080 * 1081 * Directory permissions in general are tested for NLC_CREATE if the file 1082 * does not exist, NLC_DELETE if the file does exist, and NLC_RENAME_DST 1083 * whether the file exists or not. 1084 * 1085 * The directory sticky bit is tested for NLC_DELETE and NLC_RENAME_DST, 1086 * the latter is only tested if the target exists. 1087 * 1088 * The passed ncp must be referenced and locked. If it is already resolved 1089 * it may be locked shared but otherwise should be locked exclusively. 1090 */ 1091 static int 1092 naccess(struct nchandle *nch, int nflags, struct ucred *cred, int *nflagsp) 1093 { 1094 struct vnode *vp; 1095 struct vattr va; 1096 struct namecache *ncp; 1097 int error; 1098 int cflags; 1099 1100 KKASSERT(cache_lockstatus(nch) > 0); 1101 1102 ncp = nch->ncp; 1103 if (ncp->nc_flag & NCF_UNRESOLVED) { 1104 cache_resolve(nch, cred); 1105 ncp = nch->ncp; 1106 } 1107 error = ncp->nc_error; 1108 1109 /* 1110 * Directory permissions checks. Silently ignore ENOENT if these 1111 * tests pass. It isn't an error. 1112 * 1113 * We can safely resolve ncp->nc_parent because ncp is currently 1114 * locked. 1115 */ 1116 if (nflags & (NLC_CREATE | NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST)) { 1117 if (((nflags & NLC_CREATE) && ncp->nc_vp == NULL) || 1118 ((nflags & NLC_DELETE) && ncp->nc_vp != NULL) || 1119 ((nflags & NLC_RENAME_SRC) && ncp->nc_vp != NULL) || 1120 (nflags & NLC_RENAME_DST) 1121 ) { 1122 struct nchandle par; 1123 1124 if ((par.ncp = ncp->nc_parent) == NULL) { 1125 if (error != EAGAIN) 1126 error = EINVAL; 1127 } else if (error == 0 || error == ENOENT) { 1128 par.mount = nch->mount; 1129 cache_hold(&par); 1130 cache_lock_maybe_shared(&par, 0); 1131 error = naccess(&par, NLC_WRITE, cred, NULL); 1132 cache_put(&par); 1133 } 1134 } 1135 } 1136 1137 /* 1138 * NLC_EXCL check. Target file must not exist. 1139 */ 1140 if (error == 0 && (nflags & NLC_EXCL) && ncp->nc_vp != NULL) 1141 error = EEXIST; 1142 1143 /* 1144 * Get the vnode attributes so we can do the rest of our checks. 1145 * 1146 * NOTE: We only call naccess_va() if the target exists. 1147 */ 1148 if (error == 0) { 1149 error = cache_vget(nch, cred, LK_SHARED, &vp); 1150 if (error == ENOENT) { 1151 /* 1152 * Silently zero-out ENOENT if creating or renaming 1153 * (rename target). It isn't an error. 1154 */ 1155 if (nflags & (NLC_CREATE | NLC_RENAME_DST)) 1156 error = 0; 1157 } else if (error == 0) { 1158 /* 1159 * Get the vnode attributes and check for illegal O_TRUNC 1160 * requests and read-only mounts. 1161 * 1162 * NOTE: You can still open devices on read-only mounts for 1163 * writing. 1164 * 1165 * NOTE: creates/deletes/renames are handled by the NLC_WRITE 1166 * check on the parent directory above. 1167 * 1168 * XXX cache the va in the namecache or in the vnode 1169 */ 1170 error = VOP_GETATTR(vp, &va); 1171 if (error == 0 && (nflags & NLC_TRUNCATE)) { 1172 switch(va.va_type) { 1173 case VREG: 1174 case VDATABASE: 1175 case VCHR: 1176 case VBLK: 1177 case VFIFO: 1178 break; 1179 case VDIR: 1180 error = EISDIR; 1181 break; 1182 default: 1183 error = EINVAL; 1184 break; 1185 } 1186 } 1187 if (error == 0 && (nflags & NLC_WRITE) && vp->v_mount && 1188 (vp->v_mount->mnt_flag & MNT_RDONLY) 1189 ) { 1190 switch(va.va_type) { 1191 case VDIR: 1192 case VLNK: 1193 case VREG: 1194 case VDATABASE: 1195 error = EROFS; 1196 break; 1197 default: 1198 break; 1199 } 1200 } 1201 vput(vp); 1202 1203 /* 1204 * Check permissions based on file attributes. The passed 1205 * flags (*nflagsp) are modified with feedback based on 1206 * special attributes and requirements. 1207 */ 1208 if (error == 0) { 1209 /* 1210 * Adjust the returned (*nflagsp) if non-NULL. 1211 */ 1212 if (nflagsp) { 1213 if ((va.va_mode & VSVTX) && va.va_uid != cred->cr_uid) 1214 *nflagsp |= NLC_STICKY; 1215 if (va.va_flags & APPEND) 1216 *nflagsp |= NLC_APPENDONLY; 1217 if (va.va_flags & IMMUTABLE) 1218 *nflagsp |= NLC_IMMUTABLE; 1219 } 1220 1221 /* 1222 * Track swapcache management flags in the namecache. 1223 * 1224 * Calculate the flags based on the current vattr info 1225 * and recalculate the inherited flags from the parent 1226 * (the original cache linkage may have occurred without 1227 * getattrs and thus have stale flags). 1228 */ 1229 cflags = 0; 1230 if (va.va_flags & SF_NOCACHE) 1231 cflags |= NCF_SF_NOCACHE; 1232 if (va.va_flags & UF_CACHE) 1233 cflags |= NCF_UF_CACHE; 1234 if (ncp->nc_parent) { 1235 if (ncp->nc_parent->nc_flag & 1236 (NCF_SF_NOCACHE | NCF_SF_PNOCACHE)) { 1237 cflags |= NCF_SF_PNOCACHE; 1238 } 1239 if (ncp->nc_parent->nc_flag & 1240 (NCF_UF_CACHE | NCF_UF_PCACHE)) { 1241 cflags |= NCF_UF_PCACHE; 1242 } 1243 } 1244 1245 /* 1246 * We're not supposed to update nc_flag when holding a shared 1247 * lock, but we allow the case for certain flags. Note that 1248 * holding an exclusive lock allows updating nc_flag without 1249 * atomics. nc_flag is not allowe to be updated at all unless 1250 * a shared or exclusive lock is held. 1251 */ 1252 atomic_clear_short(&ncp->nc_flag, 1253 (NCF_SF_NOCACHE | NCF_UF_CACHE | 1254 NCF_SF_PNOCACHE | NCF_UF_PCACHE) & ~cflags); 1255 atomic_set_short(&ncp->nc_flag, cflags); 1256 1257 /* 1258 * Process general access. 1259 */ 1260 error = naccess_va(&va, nflags, cred); 1261 } 1262 } 1263 } 1264 return(error); 1265 } 1266 1267 /* 1268 * Check the requested access against the given vattr using cred. 1269 */ 1270 int 1271 naccess_va(struct vattr *va, int nflags, struct ucred *cred) 1272 { 1273 int i; 1274 int vmode; 1275 1276 /* 1277 * Test the immutable bit. Creations, deletions, renames (source 1278 * or destination) are not allowed. chown/chmod/other is also not 1279 * allowed but is handled by SETATTR. Hardlinks to the immutable 1280 * file are allowed. 1281 * 1282 * If the directory is set to immutable then creations, deletions, 1283 * renames (source or dest) and hardlinks to files within the directory 1284 * are not allowed, and regular files opened through the directory may 1285 * not be written to or truncated (unless a special device). 1286 * 1287 * NOTE! New hardlinks to immutable files work but new hardlinks to 1288 * files, immutable or not, sitting inside an immutable directory are 1289 * not allowed. As always if the file is hardlinked via some other 1290 * path additional hardlinks may be possible even if the file is marked 1291 * immutable. The sysop needs to create a closure by checking the hard 1292 * link count. Once closure is achieved you are good, and security 1293 * scripts should check link counts anyway. 1294 * 1295 * Writes and truncations are only allowed on special devices. 1296 */ 1297 if ((va->va_flags & IMMUTABLE) || (nflags & NLC_IMMUTABLE)) { 1298 if ((nflags & NLC_IMMUTABLE) && (nflags & NLC_HLINK)) 1299 return (EPERM); 1300 if (nflags & (NLC_CREATE | NLC_DELETE | 1301 NLC_RENAME_SRC | NLC_RENAME_DST)) { 1302 return (EPERM); 1303 } 1304 if (nflags & (NLC_WRITE | NLC_TRUNCATE)) { 1305 switch(va->va_type) { 1306 case VDIR: 1307 return (EISDIR); 1308 case VLNK: 1309 case VREG: 1310 case VDATABASE: 1311 return (EPERM); 1312 default: 1313 break; 1314 } 1315 } 1316 } 1317 1318 /* 1319 * Test the no-unlink and append-only bits for opens, rename targets, 1320 * and deletions. These bits are not tested for creations or 1321 * rename sources. 1322 * 1323 * Unlike FreeBSD we allow a file with APPEND set to be renamed. 1324 * If you do not wish this you must also set NOUNLINK. 1325 * 1326 * If the governing directory is marked APPEND-only it implies 1327 * NOUNLINK for all entries in the directory. 1328 */ 1329 if (((va->va_flags & NOUNLINK) || (nflags & NLC_APPENDONLY)) && 1330 (nflags & (NLC_DELETE | NLC_RENAME_SRC | NLC_RENAME_DST)) 1331 ) { 1332 return (EPERM); 1333 } 1334 1335 /* 1336 * A file marked append-only may not be deleted but can be renamed. 1337 */ 1338 if ((va->va_flags & APPEND) && 1339 (nflags & (NLC_DELETE | NLC_RENAME_DST)) 1340 ) { 1341 return (EPERM); 1342 } 1343 1344 /* 1345 * A file marked append-only which is opened for writing must also 1346 * be opened O_APPEND. 1347 */ 1348 if ((va->va_flags & APPEND) && (nflags & (NLC_OPEN | NLC_TRUNCATE))) { 1349 if (nflags & NLC_TRUNCATE) 1350 return (EPERM); 1351 if ((nflags & (NLC_OPEN | NLC_WRITE)) == (NLC_OPEN | NLC_WRITE)) { 1352 if ((nflags & NLC_APPEND) == 0) 1353 return (EPERM); 1354 } 1355 } 1356 1357 /* 1358 * root gets universal access 1359 */ 1360 if (cred->cr_uid == 0) 1361 return(0); 1362 1363 /* 1364 * Check owner perms. 1365 * 1366 * If NLC_OWN is set the owner of the file is allowed no matter when 1367 * the owner-mode bits say (utimes). 1368 */ 1369 vmode = 0; 1370 if (nflags & NLC_READ) 1371 vmode |= S_IRUSR; 1372 if (nflags & NLC_WRITE) 1373 vmode |= S_IWUSR; 1374 if (nflags & NLC_EXEC) 1375 vmode |= S_IXUSR; 1376 1377 if (cred->cr_uid == va->va_uid) { 1378 if ((nflags & NLC_OWN) == 0) { 1379 if ((vmode & va->va_mode) != vmode) 1380 return(EACCES); 1381 } 1382 return(0); 1383 } 1384 1385 /* 1386 * If NLC_STICKY is set only the owner may delete or rename a file. 1387 * This bit is typically set on /tmp. 1388 * 1389 * Note that the NLC_READ/WRITE/EXEC bits are not typically set in 1390 * the specific delete or rename case. For deletions and renames we 1391 * usually just care about directory permissions, not file permissions. 1392 */ 1393 if ((nflags & NLC_STICKY) && 1394 (nflags & (NLC_RENAME_SRC | NLC_RENAME_DST | NLC_DELETE))) { 1395 return(EACCES); 1396 } 1397 1398 /* 1399 * Check group perms 1400 */ 1401 vmode >>= 3; 1402 for (i = 0; i < cred->cr_ngroups; ++i) { 1403 if (va->va_gid == cred->cr_groups[i]) { 1404 if ((vmode & va->va_mode) != vmode) 1405 return(EACCES); 1406 return(0); 1407 } 1408 } 1409 1410 /* 1411 * Check world perms 1412 */ 1413 vmode >>= 3; 1414 if ((vmode & va->va_mode) != vmode) 1415 return(EACCES); 1416 return(0); 1417 } 1418 1419