1 /* 2 * linux/fs/nfsd/nfsfh.c 3 * 4 * NFS server file handle treatment. 5 * 6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> 7 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org> 8 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999 9 * ... and again Southern-Winter 2001 to support export_operations 10 */ 11 12 #include <linux/slab.h> 13 #include <linux/fs.h> 14 #include <linux/unistd.h> 15 #include <linux/string.h> 16 #include <linux/stat.h> 17 #include <linux/dcache.h> 18 #include <linux/exportfs.h> 19 #include <linux/mount.h> 20 21 #include <linux/sunrpc/clnt.h> 22 #include <linux/sunrpc/svc.h> 23 #include <linux/sunrpc/svcauth_gss.h> 24 #include <linux/nfsd/nfsd.h> 25 #include "auth.h" 26 27 #define NFSDDBG_FACILITY NFSDDBG_FH 28 29 30 static int nfsd_nr_verified; 31 static int nfsd_nr_put; 32 33 /* 34 * our acceptability function. 35 * if NOSUBTREECHECK, accept anything 36 * if not, require that we can walk up to exp->ex_dentry 37 * doing some checks on the 'x' bits 38 */ 39 static int nfsd_acceptable(void *expv, struct dentry *dentry) 40 { 41 struct svc_export *exp = expv; 42 int rv; 43 struct dentry *tdentry; 44 struct dentry *parent; 45 46 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) 47 return 1; 48 49 tdentry = dget(dentry); 50 while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) { 51 /* make sure parents give x permission to user */ 52 int err; 53 parent = dget_parent(tdentry); 54 err = inode_permission(parent->d_inode, MAY_EXEC); 55 if (err < 0) { 56 dput(parent); 57 break; 58 } 59 dput(tdentry); 60 tdentry = parent; 61 } 62 if (tdentry != exp->ex_path.dentry) 63 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name); 64 rv = (tdentry == exp->ex_path.dentry); 65 dput(tdentry); 66 return rv; 67 } 68 69 /* Type check. The correct error return for type mismatches does not seem to be 70 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a 71 * comment in the NFSv3 spec says this is incorrect (implementation notes for 72 * the write call). 73 */ 74 static inline __be32 75 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type) 76 { 77 /* Type can be negative when creating hardlinks - not to a dir */ 78 if (type > 0 && (mode & S_IFMT) != type) { 79 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK) 80 return nfserr_symlink; 81 else if (type == S_IFDIR) 82 return nfserr_notdir; 83 else if ((mode & S_IFMT) == S_IFDIR) 84 return nfserr_isdir; 85 else 86 return nfserr_inval; 87 } 88 if (type < 0 && (mode & S_IFMT) == -type) { 89 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK) 90 return nfserr_symlink; 91 else if (type == -S_IFDIR) 92 return nfserr_isdir; 93 else 94 return nfserr_notdir; 95 } 96 return 0; 97 } 98 99 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp, 100 struct svc_export *exp) 101 { 102 /* Check if the request originated from a secure port. */ 103 if (!rqstp->rq_secure && EX_SECURE(exp)) { 104 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 105 dprintk(KERN_WARNING 106 "nfsd: request from insecure port %s!\n", 107 svc_print_addr(rqstp, buf, sizeof(buf))); 108 return nfserr_perm; 109 } 110 111 /* Set user creds for this exportpoint */ 112 return nfserrno(nfsd_setuser(rqstp, exp)); 113 } 114 115 /* 116 * Use the given filehandle to look up the corresponding export and 117 * dentry. On success, the results are used to set fh_export and 118 * fh_dentry. 119 */ 120 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp) 121 { 122 struct knfsd_fh *fh = &fhp->fh_handle; 123 struct fid *fid = NULL, sfid; 124 struct svc_export *exp; 125 struct dentry *dentry; 126 int fileid_type; 127 int data_left = fh->fh_size/4; 128 __be32 error; 129 130 error = nfserr_stale; 131 if (rqstp->rq_vers > 2) 132 error = nfserr_badhandle; 133 if (rqstp->rq_vers == 4 && fh->fh_size == 0) 134 return nfserr_nofilehandle; 135 136 if (fh->fh_version == 1) { 137 int len; 138 139 if (--data_left < 0) 140 return error; 141 if (fh->fh_auth_type != 0) 142 return error; 143 len = key_len(fh->fh_fsid_type) / 4; 144 if (len == 0) 145 return error; 146 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) { 147 /* deprecated, convert to type 3 */ 148 len = key_len(FSID_ENCODE_DEV)/4; 149 fh->fh_fsid_type = FSID_ENCODE_DEV; 150 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1]))); 151 fh->fh_fsid[1] = fh->fh_fsid[2]; 152 } 153 data_left -= len; 154 if (data_left < 0) 155 return error; 156 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth); 157 fid = (struct fid *)(fh->fh_auth + len); 158 } else { 159 __u32 tfh[2]; 160 dev_t xdev; 161 ino_t xino; 162 163 if (fh->fh_size != NFS_FHSIZE) 164 return error; 165 /* assume old filehandle format */ 166 xdev = old_decode_dev(fh->ofh_xdev); 167 xino = u32_to_ino_t(fh->ofh_xino); 168 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL); 169 exp = rqst_exp_find(rqstp, FSID_DEV, tfh); 170 } 171 172 error = nfserr_stale; 173 if (PTR_ERR(exp) == -ENOENT) 174 return error; 175 176 if (IS_ERR(exp)) 177 return nfserrno(PTR_ERR(exp)); 178 179 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) { 180 /* Elevate privileges so that the lack of 'r' or 'x' 181 * permission on some parent directory will 182 * not stop exportfs_decode_fh from being able 183 * to reconnect a directory into the dentry cache. 184 * The same problem can affect "SUBTREECHECK" exports, 185 * but as nfsd_acceptable depends on correct 186 * access control settings being in effect, we cannot 187 * fix that case easily. 188 */ 189 current->cap_effective = 190 cap_raise_nfsd_set(current->cap_effective, 191 current->cap_permitted); 192 } else { 193 error = nfsd_setuser_and_check_port(rqstp, exp); 194 if (error) 195 goto out; 196 } 197 198 /* 199 * Look up the dentry using the NFS file handle. 200 */ 201 error = nfserr_stale; 202 if (rqstp->rq_vers > 2) 203 error = nfserr_badhandle; 204 205 if (fh->fh_version != 1) { 206 sfid.i32.ino = fh->ofh_ino; 207 sfid.i32.gen = fh->ofh_generation; 208 sfid.i32.parent_ino = fh->ofh_dirino; 209 fid = &sfid; 210 data_left = 3; 211 if (fh->ofh_dirino == 0) 212 fileid_type = FILEID_INO32_GEN; 213 else 214 fileid_type = FILEID_INO32_GEN_PARENT; 215 } else 216 fileid_type = fh->fh_fileid_type; 217 218 if (fileid_type == FILEID_ROOT) 219 dentry = dget(exp->ex_path.dentry); 220 else { 221 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid, 222 data_left, fileid_type, 223 nfsd_acceptable, exp); 224 } 225 if (dentry == NULL) 226 goto out; 227 if (IS_ERR(dentry)) { 228 if (PTR_ERR(dentry) != -EINVAL) 229 error = nfserrno(PTR_ERR(dentry)); 230 goto out; 231 } 232 233 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) { 234 error = nfsd_setuser_and_check_port(rqstp, exp); 235 if (error) { 236 dput(dentry); 237 goto out; 238 } 239 } 240 241 if (S_ISDIR(dentry->d_inode->i_mode) && 242 (dentry->d_flags & DCACHE_DISCONNECTED)) { 243 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n", 244 dentry->d_parent->d_name.name, dentry->d_name.name); 245 } 246 247 fhp->fh_dentry = dentry; 248 fhp->fh_export = exp; 249 nfsd_nr_verified++; 250 return 0; 251 out: 252 exp_put(exp); 253 return error; 254 } 255 256 /* 257 * Perform sanity checks on the dentry in a client's file handle. 258 * 259 * Note that the file handle dentry may need to be freed even after 260 * an error return. 261 * 262 * This is only called at the start of an nfsproc call, so fhp points to 263 * a svc_fh which is all 0 except for the over-the-wire file handle. 264 */ 265 __be32 266 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) 267 { 268 struct svc_export *exp; 269 struct dentry *dentry; 270 __be32 error; 271 272 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp)); 273 274 if (!fhp->fh_dentry) { 275 error = nfsd_set_fh_dentry(rqstp, fhp); 276 if (error) 277 goto out; 278 dentry = fhp->fh_dentry; 279 exp = fhp->fh_export; 280 } else { 281 /* 282 * just rechecking permissions 283 * (e.g. nfsproc_create calls fh_verify, then nfsd_create 284 * does as well) 285 */ 286 dprintk("nfsd: fh_verify - just checking\n"); 287 dentry = fhp->fh_dentry; 288 exp = fhp->fh_export; 289 /* 290 * Set user creds for this exportpoint; necessary even 291 * in the "just checking" case because this may be a 292 * filehandle that was created by fh_compose, and that 293 * is about to be used in another nfsv4 compound 294 * operation. 295 */ 296 error = nfsd_setuser_and_check_port(rqstp, exp); 297 if (error) 298 goto out; 299 } 300 301 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); 302 if (error) 303 goto out; 304 305 if (!(access & NFSD_MAY_LOCK)) { 306 /* 307 * pseudoflavor restrictions are not enforced on NLM, 308 * which clients virtually always use auth_sys for, 309 * even while using RPCSEC_GSS for NFS. 310 */ 311 error = check_nfsd_access(exp, rqstp); 312 if (error) 313 goto out; 314 } 315 316 /* Finally, check access permissions. */ 317 error = nfsd_permission(rqstp, exp, dentry, access); 318 319 if (error) { 320 dprintk("fh_verify: %s/%s permission failure, " 321 "acc=%x, error=%d\n", 322 dentry->d_parent->d_name.name, 323 dentry->d_name.name, 324 access, ntohl(error)); 325 } 326 out: 327 if (error == nfserr_stale) 328 nfsdstats.fh_stale++; 329 return error; 330 } 331 332 333 /* 334 * Compose a file handle for an NFS reply. 335 * 336 * Note that when first composed, the dentry may not yet have 337 * an inode. In this case a call to fh_update should be made 338 * before the fh goes out on the wire ... 339 */ 340 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp, 341 struct dentry *dentry) 342 { 343 if (dentry != exp->ex_path.dentry) { 344 struct fid *fid = (struct fid *) 345 (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1); 346 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4; 347 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK); 348 349 fhp->fh_handle.fh_fileid_type = 350 exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck); 351 fhp->fh_handle.fh_size += maxsize * 4; 352 } else { 353 fhp->fh_handle.fh_fileid_type = FILEID_ROOT; 354 } 355 } 356 357 /* 358 * for composing old style file handles 359 */ 360 static inline void _fh_update_old(struct dentry *dentry, 361 struct svc_export *exp, 362 struct knfsd_fh *fh) 363 { 364 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino); 365 fh->ofh_generation = dentry->d_inode->i_generation; 366 if (S_ISDIR(dentry->d_inode->i_mode) || 367 (exp->ex_flags & NFSEXP_NOSUBTREECHECK)) 368 fh->ofh_dirino = 0; 369 } 370 371 __be32 372 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, 373 struct svc_fh *ref_fh) 374 { 375 /* ref_fh is a reference file handle. 376 * if it is non-null and for the same filesystem, then we should compose 377 * a filehandle which is of the same version, where possible. 378 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca 379 * Then create a 32byte filehandle using nfs_fhbase_old 380 * 381 */ 382 383 u8 version; 384 u8 fsid_type = 0; 385 struct inode * inode = dentry->d_inode; 386 struct dentry *parent = dentry->d_parent; 387 __u32 *datap; 388 dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev; 389 int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root); 390 391 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n", 392 MAJOR(ex_dev), MINOR(ex_dev), 393 (long) exp->ex_path.dentry->d_inode->i_ino, 394 parent->d_name.name, dentry->d_name.name, 395 (inode ? inode->i_ino : 0)); 396 397 /* Choose filehandle version and fsid type based on 398 * the reference filehandle (if it is in the same export) 399 * or the export options. 400 */ 401 retry: 402 version = 1; 403 if (ref_fh && ref_fh->fh_export == exp) { 404 version = ref_fh->fh_handle.fh_version; 405 fsid_type = ref_fh->fh_handle.fh_fsid_type; 406 407 if (ref_fh == fhp) 408 fh_put(ref_fh); 409 ref_fh = NULL; 410 411 switch (version) { 412 case 0xca: 413 fsid_type = FSID_DEV; 414 break; 415 case 1: 416 break; 417 default: 418 goto retry; 419 } 420 421 /* Need to check that this type works for this 422 * export point. As the fsid -> filesystem mapping 423 * was guided by user-space, there is no guarantee 424 * that the filesystem actually supports that fsid 425 * type. If it doesn't we loop around again without 426 * ref_fh set. 427 */ 428 switch(fsid_type) { 429 case FSID_DEV: 430 if (!old_valid_dev(ex_dev)) 431 goto retry; 432 /* FALL THROUGH */ 433 case FSID_MAJOR_MINOR: 434 case FSID_ENCODE_DEV: 435 if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags 436 & FS_REQUIRES_DEV)) 437 goto retry; 438 break; 439 case FSID_NUM: 440 if (! (exp->ex_flags & NFSEXP_FSID)) 441 goto retry; 442 break; 443 case FSID_UUID8: 444 case FSID_UUID16: 445 if (!root_export) 446 goto retry; 447 /* fall through */ 448 case FSID_UUID4_INUM: 449 case FSID_UUID16_INUM: 450 if (exp->ex_uuid == NULL) 451 goto retry; 452 break; 453 } 454 } else if (exp->ex_uuid) { 455 if (fhp->fh_maxsize >= 64) { 456 if (root_export) 457 fsid_type = FSID_UUID16; 458 else 459 fsid_type = FSID_UUID16_INUM; 460 } else { 461 if (root_export) 462 fsid_type = FSID_UUID8; 463 else 464 fsid_type = FSID_UUID4_INUM; 465 } 466 } else if (exp->ex_flags & NFSEXP_FSID) 467 fsid_type = FSID_NUM; 468 else if (!old_valid_dev(ex_dev)) 469 /* for newer device numbers, we must use a newer fsid format */ 470 fsid_type = FSID_ENCODE_DEV; 471 else 472 fsid_type = FSID_DEV; 473 474 if (ref_fh == fhp) 475 fh_put(ref_fh); 476 477 if (fhp->fh_locked || fhp->fh_dentry) { 478 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n", 479 parent->d_name.name, dentry->d_name.name); 480 } 481 if (fhp->fh_maxsize < NFS_FHSIZE) 482 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n", 483 fhp->fh_maxsize, 484 parent->d_name.name, dentry->d_name.name); 485 486 fhp->fh_dentry = dget(dentry); /* our internal copy */ 487 fhp->fh_export = exp; 488 cache_get(&exp->h); 489 490 if (version == 0xca) { 491 /* old style filehandle please */ 492 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE); 493 fhp->fh_handle.fh_size = NFS_FHSIZE; 494 fhp->fh_handle.ofh_dcookie = 0xfeebbaca; 495 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev); 496 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev; 497 fhp->fh_handle.ofh_xino = 498 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino); 499 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry)); 500 if (inode) 501 _fh_update_old(dentry, exp, &fhp->fh_handle); 502 } else { 503 int len; 504 fhp->fh_handle.fh_version = 1; 505 fhp->fh_handle.fh_auth_type = 0; 506 datap = fhp->fh_handle.fh_auth+0; 507 fhp->fh_handle.fh_fsid_type = fsid_type; 508 mk_fsid(fsid_type, datap, ex_dev, 509 exp->ex_path.dentry->d_inode->i_ino, 510 exp->ex_fsid, exp->ex_uuid); 511 512 len = key_len(fsid_type); 513 datap += len/4; 514 fhp->fh_handle.fh_size = 4 + len; 515 516 if (inode) 517 _fh_update(fhp, exp, dentry); 518 if (fhp->fh_handle.fh_fileid_type == 255) 519 return nfserr_opnotsupp; 520 } 521 522 nfsd_nr_verified++; 523 return 0; 524 } 525 526 /* 527 * Update file handle information after changing a dentry. 528 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create 529 */ 530 __be32 531 fh_update(struct svc_fh *fhp) 532 { 533 struct dentry *dentry; 534 535 if (!fhp->fh_dentry) 536 goto out_bad; 537 538 dentry = fhp->fh_dentry; 539 if (!dentry->d_inode) 540 goto out_negative; 541 if (fhp->fh_handle.fh_version != 1) { 542 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle); 543 } else { 544 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT) 545 goto out; 546 547 _fh_update(fhp, fhp->fh_export, dentry); 548 if (fhp->fh_handle.fh_fileid_type == 255) 549 return nfserr_opnotsupp; 550 } 551 out: 552 return 0; 553 554 out_bad: 555 printk(KERN_ERR "fh_update: fh not verified!\n"); 556 goto out; 557 out_negative: 558 printk(KERN_ERR "fh_update: %s/%s still negative!\n", 559 dentry->d_parent->d_name.name, dentry->d_name.name); 560 goto out; 561 } 562 563 /* 564 * Release a file handle. 565 */ 566 void 567 fh_put(struct svc_fh *fhp) 568 { 569 struct dentry * dentry = fhp->fh_dentry; 570 struct svc_export * exp = fhp->fh_export; 571 if (dentry) { 572 fh_unlock(fhp); 573 fhp->fh_dentry = NULL; 574 dput(dentry); 575 #ifdef CONFIG_NFSD_V3 576 fhp->fh_pre_saved = 0; 577 fhp->fh_post_saved = 0; 578 #endif 579 nfsd_nr_put++; 580 } 581 if (exp) { 582 cache_put(&exp->h, &svc_export_cache); 583 fhp->fh_export = NULL; 584 } 585 return; 586 } 587 588 /* 589 * Shorthand for dprintk()'s 590 */ 591 char * SVCFH_fmt(struct svc_fh *fhp) 592 { 593 struct knfsd_fh *fh = &fhp->fh_handle; 594 595 static char buf[80]; 596 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x", 597 fh->fh_size, 598 fh->fh_base.fh_pad[0], 599 fh->fh_base.fh_pad[1], 600 fh->fh_base.fh_pad[2], 601 fh->fh_base.fh_pad[3], 602 fh->fh_base.fh_pad[4], 603 fh->fh_base.fh_pad[5]); 604 return buf; 605 } 606 607 enum fsid_source fsid_source(struct svc_fh *fhp) 608 { 609 if (fhp->fh_handle.fh_version != 1) 610 return FSIDSOURCE_DEV; 611 switch(fhp->fh_handle.fh_fsid_type) { 612 case FSID_DEV: 613 case FSID_ENCODE_DEV: 614 case FSID_MAJOR_MINOR: 615 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags 616 & FS_REQUIRES_DEV) 617 return FSIDSOURCE_DEV; 618 break; 619 case FSID_NUM: 620 if (fhp->fh_export->ex_flags & NFSEXP_FSID) 621 return FSIDSOURCE_FSID; 622 break; 623 default: 624 break; 625 } 626 /* either a UUID type filehandle, or the filehandle doesn't 627 * match the export. 628 */ 629 if (fhp->fh_export->ex_flags & NFSEXP_FSID) 630 return FSIDSOURCE_FSID; 631 if (fhp->fh_export->ex_uuid) 632 return FSIDSOURCE_UUID; 633 return FSIDSOURCE_DEV; 634 } 635