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 = permission(parent->d_inode, MAY_EXEC, NULL); 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 error = nfsd_setuser_and_check_port(rqstp, exp); 180 if (error) 181 goto out; 182 183 /* 184 * Look up the dentry using the NFS file handle. 185 */ 186 error = nfserr_stale; 187 if (rqstp->rq_vers > 2) 188 error = nfserr_badhandle; 189 190 if (fh->fh_version != 1) { 191 sfid.i32.ino = fh->ofh_ino; 192 sfid.i32.gen = fh->ofh_generation; 193 sfid.i32.parent_ino = fh->ofh_dirino; 194 fid = &sfid; 195 data_left = 3; 196 if (fh->ofh_dirino == 0) 197 fileid_type = FILEID_INO32_GEN; 198 else 199 fileid_type = FILEID_INO32_GEN_PARENT; 200 } else 201 fileid_type = fh->fh_fileid_type; 202 203 if (fileid_type == FILEID_ROOT) 204 dentry = dget(exp->ex_path.dentry); 205 else { 206 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid, 207 data_left, fileid_type, 208 nfsd_acceptable, exp); 209 } 210 if (dentry == NULL) 211 goto out; 212 if (IS_ERR(dentry)) { 213 if (PTR_ERR(dentry) != -EINVAL) 214 error = nfserrno(PTR_ERR(dentry)); 215 goto out; 216 } 217 218 if (S_ISDIR(dentry->d_inode->i_mode) && 219 (dentry->d_flags & DCACHE_DISCONNECTED)) { 220 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n", 221 dentry->d_parent->d_name.name, dentry->d_name.name); 222 } 223 224 fhp->fh_dentry = dentry; 225 fhp->fh_export = exp; 226 nfsd_nr_verified++; 227 return 0; 228 out: 229 exp_put(exp); 230 return error; 231 } 232 233 /* 234 * Perform sanity checks on the dentry in a client's file handle. 235 * 236 * Note that the file handle dentry may need to be freed even after 237 * an error return. 238 * 239 * This is only called at the start of an nfsproc call, so fhp points to 240 * a svc_fh which is all 0 except for the over-the-wire file handle. 241 */ 242 __be32 243 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) 244 { 245 struct svc_export *exp; 246 struct dentry *dentry; 247 __be32 error; 248 249 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp)); 250 251 if (!fhp->fh_dentry) { 252 error = nfsd_set_fh_dentry(rqstp, fhp); 253 if (error) 254 goto out; 255 dentry = fhp->fh_dentry; 256 exp = fhp->fh_export; 257 } else { 258 /* 259 * just rechecking permissions 260 * (e.g. nfsproc_create calls fh_verify, then nfsd_create 261 * does as well) 262 */ 263 dprintk("nfsd: fh_verify - just checking\n"); 264 dentry = fhp->fh_dentry; 265 exp = fhp->fh_export; 266 /* 267 * Set user creds for this exportpoint; necessary even 268 * in the "just checking" case because this may be a 269 * filehandle that was created by fh_compose, and that 270 * is about to be used in another nfsv4 compound 271 * operation. 272 */ 273 error = nfsd_setuser_and_check_port(rqstp, exp); 274 if (error) 275 goto out; 276 } 277 278 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); 279 if (error) 280 goto out; 281 282 if (!(access & MAY_LOCK)) { 283 /* 284 * pseudoflavor restrictions are not enforced on NLM, 285 * which clients virtually always use auth_sys for, 286 * even while using RPCSEC_GSS for NFS. 287 */ 288 error = check_nfsd_access(exp, rqstp); 289 if (error) 290 goto out; 291 } 292 293 /* Finally, check access permissions. */ 294 error = nfsd_permission(rqstp, exp, dentry, access); 295 296 if (error) { 297 dprintk("fh_verify: %s/%s permission failure, " 298 "acc=%x, error=%d\n", 299 dentry->d_parent->d_name.name, 300 dentry->d_name.name, 301 access, ntohl(error)); 302 } 303 out: 304 if (error == nfserr_stale) 305 nfsdstats.fh_stale++; 306 return error; 307 } 308 309 310 /* 311 * Compose a file handle for an NFS reply. 312 * 313 * Note that when first composed, the dentry may not yet have 314 * an inode. In this case a call to fh_update should be made 315 * before the fh goes out on the wire ... 316 */ 317 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp, 318 struct dentry *dentry) 319 { 320 if (dentry != exp->ex_path.dentry) { 321 struct fid *fid = (struct fid *) 322 (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1); 323 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4; 324 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK); 325 326 fhp->fh_handle.fh_fileid_type = 327 exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck); 328 fhp->fh_handle.fh_size += maxsize * 4; 329 } else { 330 fhp->fh_handle.fh_fileid_type = FILEID_ROOT; 331 } 332 } 333 334 /* 335 * for composing old style file handles 336 */ 337 static inline void _fh_update_old(struct dentry *dentry, 338 struct svc_export *exp, 339 struct knfsd_fh *fh) 340 { 341 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino); 342 fh->ofh_generation = dentry->d_inode->i_generation; 343 if (S_ISDIR(dentry->d_inode->i_mode) || 344 (exp->ex_flags & NFSEXP_NOSUBTREECHECK)) 345 fh->ofh_dirino = 0; 346 } 347 348 __be32 349 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, 350 struct svc_fh *ref_fh) 351 { 352 /* ref_fh is a reference file handle. 353 * if it is non-null and for the same filesystem, then we should compose 354 * a filehandle which is of the same version, where possible. 355 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca 356 * Then create a 32byte filehandle using nfs_fhbase_old 357 * 358 */ 359 360 u8 version; 361 u8 fsid_type = 0; 362 struct inode * inode = dentry->d_inode; 363 struct dentry *parent = dentry->d_parent; 364 __u32 *datap; 365 dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev; 366 int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root); 367 368 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n", 369 MAJOR(ex_dev), MINOR(ex_dev), 370 (long) exp->ex_path.dentry->d_inode->i_ino, 371 parent->d_name.name, dentry->d_name.name, 372 (inode ? inode->i_ino : 0)); 373 374 /* Choose filehandle version and fsid type based on 375 * the reference filehandle (if it is in the same export) 376 * or the export options. 377 */ 378 retry: 379 version = 1; 380 if (ref_fh && ref_fh->fh_export == exp) { 381 version = ref_fh->fh_handle.fh_version; 382 fsid_type = ref_fh->fh_handle.fh_fsid_type; 383 384 if (ref_fh == fhp) 385 fh_put(ref_fh); 386 ref_fh = NULL; 387 388 switch (version) { 389 case 0xca: 390 fsid_type = FSID_DEV; 391 break; 392 case 1: 393 break; 394 default: 395 goto retry; 396 } 397 398 /* Need to check that this type works for this 399 * export point. As the fsid -> filesystem mapping 400 * was guided by user-space, there is no guarantee 401 * that the filesystem actually supports that fsid 402 * type. If it doesn't we loop around again without 403 * ref_fh set. 404 */ 405 switch(fsid_type) { 406 case FSID_DEV: 407 if (!old_valid_dev(ex_dev)) 408 goto retry; 409 /* FALL THROUGH */ 410 case FSID_MAJOR_MINOR: 411 case FSID_ENCODE_DEV: 412 if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags 413 & FS_REQUIRES_DEV)) 414 goto retry; 415 break; 416 case FSID_NUM: 417 if (! (exp->ex_flags & NFSEXP_FSID)) 418 goto retry; 419 break; 420 case FSID_UUID8: 421 case FSID_UUID16: 422 if (!root_export) 423 goto retry; 424 /* fall through */ 425 case FSID_UUID4_INUM: 426 case FSID_UUID16_INUM: 427 if (exp->ex_uuid == NULL) 428 goto retry; 429 break; 430 } 431 } else if (exp->ex_uuid) { 432 if (fhp->fh_maxsize >= 64) { 433 if (root_export) 434 fsid_type = FSID_UUID16; 435 else 436 fsid_type = FSID_UUID16_INUM; 437 } else { 438 if (root_export) 439 fsid_type = FSID_UUID8; 440 else 441 fsid_type = FSID_UUID4_INUM; 442 } 443 } else if (exp->ex_flags & NFSEXP_FSID) 444 fsid_type = FSID_NUM; 445 else if (!old_valid_dev(ex_dev)) 446 /* for newer device numbers, we must use a newer fsid format */ 447 fsid_type = FSID_ENCODE_DEV; 448 else 449 fsid_type = FSID_DEV; 450 451 if (ref_fh == fhp) 452 fh_put(ref_fh); 453 454 if (fhp->fh_locked || fhp->fh_dentry) { 455 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n", 456 parent->d_name.name, dentry->d_name.name); 457 } 458 if (fhp->fh_maxsize < NFS_FHSIZE) 459 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n", 460 fhp->fh_maxsize, 461 parent->d_name.name, dentry->d_name.name); 462 463 fhp->fh_dentry = dget(dentry); /* our internal copy */ 464 fhp->fh_export = exp; 465 cache_get(&exp->h); 466 467 if (version == 0xca) { 468 /* old style filehandle please */ 469 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE); 470 fhp->fh_handle.fh_size = NFS_FHSIZE; 471 fhp->fh_handle.ofh_dcookie = 0xfeebbaca; 472 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev); 473 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev; 474 fhp->fh_handle.ofh_xino = 475 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino); 476 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry)); 477 if (inode) 478 _fh_update_old(dentry, exp, &fhp->fh_handle); 479 } else { 480 int len; 481 fhp->fh_handle.fh_version = 1; 482 fhp->fh_handle.fh_auth_type = 0; 483 datap = fhp->fh_handle.fh_auth+0; 484 fhp->fh_handle.fh_fsid_type = fsid_type; 485 mk_fsid(fsid_type, datap, ex_dev, 486 exp->ex_path.dentry->d_inode->i_ino, 487 exp->ex_fsid, exp->ex_uuid); 488 489 len = key_len(fsid_type); 490 datap += len/4; 491 fhp->fh_handle.fh_size = 4 + len; 492 493 if (inode) 494 _fh_update(fhp, exp, dentry); 495 if (fhp->fh_handle.fh_fileid_type == 255) 496 return nfserr_opnotsupp; 497 } 498 499 nfsd_nr_verified++; 500 return 0; 501 } 502 503 /* 504 * Update file handle information after changing a dentry. 505 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create 506 */ 507 __be32 508 fh_update(struct svc_fh *fhp) 509 { 510 struct dentry *dentry; 511 512 if (!fhp->fh_dentry) 513 goto out_bad; 514 515 dentry = fhp->fh_dentry; 516 if (!dentry->d_inode) 517 goto out_negative; 518 if (fhp->fh_handle.fh_version != 1) { 519 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle); 520 } else { 521 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT) 522 goto out; 523 524 _fh_update(fhp, fhp->fh_export, dentry); 525 if (fhp->fh_handle.fh_fileid_type == 255) 526 return nfserr_opnotsupp; 527 } 528 out: 529 return 0; 530 531 out_bad: 532 printk(KERN_ERR "fh_update: fh not verified!\n"); 533 goto out; 534 out_negative: 535 printk(KERN_ERR "fh_update: %s/%s still negative!\n", 536 dentry->d_parent->d_name.name, dentry->d_name.name); 537 goto out; 538 } 539 540 /* 541 * Release a file handle. 542 */ 543 void 544 fh_put(struct svc_fh *fhp) 545 { 546 struct dentry * dentry = fhp->fh_dentry; 547 struct svc_export * exp = fhp->fh_export; 548 if (dentry) { 549 fh_unlock(fhp); 550 fhp->fh_dentry = NULL; 551 dput(dentry); 552 #ifdef CONFIG_NFSD_V3 553 fhp->fh_pre_saved = 0; 554 fhp->fh_post_saved = 0; 555 #endif 556 nfsd_nr_put++; 557 } 558 if (exp) { 559 cache_put(&exp->h, &svc_export_cache); 560 fhp->fh_export = NULL; 561 } 562 return; 563 } 564 565 /* 566 * Shorthand for dprintk()'s 567 */ 568 char * SVCFH_fmt(struct svc_fh *fhp) 569 { 570 struct knfsd_fh *fh = &fhp->fh_handle; 571 572 static char buf[80]; 573 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x", 574 fh->fh_size, 575 fh->fh_base.fh_pad[0], 576 fh->fh_base.fh_pad[1], 577 fh->fh_base.fh_pad[2], 578 fh->fh_base.fh_pad[3], 579 fh->fh_base.fh_pad[4], 580 fh->fh_base.fh_pad[5]); 581 return buf; 582 } 583 584 enum fsid_source fsid_source(struct svc_fh *fhp) 585 { 586 if (fhp->fh_handle.fh_version != 1) 587 return FSIDSOURCE_DEV; 588 switch(fhp->fh_handle.fh_fsid_type) { 589 case FSID_DEV: 590 case FSID_ENCODE_DEV: 591 case FSID_MAJOR_MINOR: 592 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags 593 & FS_REQUIRES_DEV) 594 return FSIDSOURCE_DEV; 595 break; 596 case FSID_NUM: 597 if (fhp->fh_export->ex_flags & NFSEXP_FSID) 598 return FSIDSOURCE_FSID; 599 break; 600 default: 601 break; 602 } 603 /* either a UUID type filehandle, or the filehandle doesn't 604 * match the export. 605 */ 606 if (fhp->fh_export->ex_flags & NFSEXP_FSID) 607 return FSIDSOURCE_FSID; 608 if (fhp->fh_export->ex_uuid) 609 return FSIDSOURCE_UUID; 610 return FSIDSOURCE_DEV; 611 } 612