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