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