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/sched.h> 13 #include <linux/slab.h> 14 #include <linux/smp_lock.h> 15 #include <linux/fs.h> 16 #include <linux/unistd.h> 17 #include <linux/string.h> 18 #include <linux/stat.h> 19 #include <linux/dcache.h> 20 #include <linux/mount.h> 21 #include <asm/pgtable.h> 22 23 #include <linux/sunrpc/svc.h> 24 #include <linux/nfsd/nfsd.h> 25 26 #define NFSDDBG_FACILITY NFSDDBG_FH 27 #define NFSD_PARANOIA 1 28 /* #define NFSD_DEBUG_VERBOSE 1 */ 29 30 31 static int nfsd_nr_verified; 32 static int nfsd_nr_put; 33 34 extern struct export_operations export_op_default; 35 36 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun) 37 38 /* 39 * our acceptability function. 40 * if NOSUBTREECHECK, accept anything 41 * if not, require that we can walk up to exp->ex_dentry 42 * doing some checks on the 'x' bits 43 */ 44 static int nfsd_acceptable(void *expv, struct dentry *dentry) 45 { 46 struct svc_export *exp = expv; 47 int rv; 48 struct dentry *tdentry; 49 struct dentry *parent; 50 51 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) 52 return 1; 53 54 tdentry = dget(dentry); 55 while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) { 56 /* make sure parents give x permission to user */ 57 int err; 58 parent = dget_parent(tdentry); 59 err = permission(parent->d_inode, MAY_EXEC, NULL); 60 if (err < 0) { 61 dput(parent); 62 break; 63 } 64 dput(tdentry); 65 tdentry = parent; 66 } 67 if (tdentry != exp->ex_dentry) 68 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name); 69 rv = (tdentry == exp->ex_dentry); 70 dput(tdentry); 71 return rv; 72 } 73 74 /* Type check. The correct error return for type mismatches does not seem to be 75 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a 76 * comment in the NFSv3 spec says this is incorrect (implementation notes for 77 * the write call). 78 */ 79 static inline int 80 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type) 81 { 82 /* Type can be negative when creating hardlinks - not to a dir */ 83 if (type > 0 && (mode & S_IFMT) != type) { 84 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK) 85 return nfserr_symlink; 86 else if (type == S_IFDIR) 87 return nfserr_notdir; 88 else if ((mode & S_IFMT) == S_IFDIR) 89 return nfserr_isdir; 90 else 91 return nfserr_inval; 92 } 93 if (type < 0 && (mode & S_IFMT) == -type) { 94 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK) 95 return nfserr_symlink; 96 else if (type == -S_IFDIR) 97 return nfserr_isdir; 98 else 99 return nfserr_notdir; 100 } 101 return 0; 102 } 103 104 /* 105 * Perform sanity checks on the dentry in a client's file handle. 106 * 107 * Note that the file handle dentry may need to be freed even after 108 * an error return. 109 * 110 * This is only called at the start of an nfsproc call, so fhp points to 111 * a svc_fh which is all 0 except for the over-the-wire file handle. 112 */ 113 u32 114 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) 115 { 116 struct knfsd_fh *fh = &fhp->fh_handle; 117 struct svc_export *exp = NULL; 118 struct dentry *dentry; 119 u32 error = 0; 120 121 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp)); 122 123 /* keep this filehandle for possible reference when encoding attributes */ 124 rqstp->rq_reffh = fh; 125 126 if (!fhp->fh_dentry) { 127 __u32 *datap=NULL; 128 __u32 tfh[3]; /* filehandle fragment for oldstyle filehandles */ 129 int fileid_type; 130 int data_left = fh->fh_size/4; 131 132 error = nfserr_stale; 133 if (rqstp->rq_client == NULL) 134 goto out; 135 if (rqstp->rq_vers > 2) 136 error = nfserr_badhandle; 137 if (rqstp->rq_vers == 4 && fh->fh_size == 0) 138 return nfserr_nofilehandle; 139 140 if (fh->fh_version == 1) { 141 int len; 142 datap = fh->fh_auth; 143 if (--data_left<0) goto out; 144 switch (fh->fh_auth_type) { 145 case 0: break; 146 default: goto out; 147 } 148 len = key_len(fh->fh_fsid_type) / 4; 149 if (len == 0) goto out; 150 if (fh->fh_fsid_type == 2) { 151 /* deprecated, convert to type 3 */ 152 len = 3; 153 fh->fh_fsid_type = 3; 154 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1]))); 155 fh->fh_fsid[1] = fh->fh_fsid[2]; 156 } 157 if ((data_left -= len)<0) goto out; 158 exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle); 159 datap += len; 160 } else { 161 dev_t xdev; 162 ino_t xino; 163 if (fh->fh_size != NFS_FHSIZE) 164 goto out; 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_v0(tfh, xdev, xino); 169 exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle); 170 } 171 172 error = nfserr_dropit; 173 if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN) 174 goto out; 175 176 error = nfserr_stale; 177 if (!exp || IS_ERR(exp)) 178 goto out; 179 180 /* Check if the request originated from a secure port. */ 181 error = nfserr_perm; 182 if (!rqstp->rq_secure && EX_SECURE(exp)) { 183 printk(KERN_WARNING 184 "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n", 185 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr), 186 ntohs(rqstp->rq_addr.sin_port)); 187 goto out; 188 } 189 190 /* Set user creds for this exportpoint */ 191 error = nfsd_setuser(rqstp, exp); 192 if (error) { 193 error = nfserrno(error); 194 goto out; 195 } 196 197 /* 198 * Look up the dentry using the NFS file handle. 199 */ 200 error = nfserr_stale; 201 if (rqstp->rq_vers > 2) 202 error = nfserr_badhandle; 203 204 if (fh->fh_version != 1) { 205 tfh[0] = fh->ofh_ino; 206 tfh[1] = fh->ofh_generation; 207 tfh[2] = fh->ofh_dirino; 208 datap = tfh; 209 data_left = 3; 210 if (fh->ofh_dirino == 0) 211 fileid_type = 1; 212 else 213 fileid_type = 2; 214 } else 215 fileid_type = fh->fh_fileid_type; 216 217 if (fileid_type == 0) 218 dentry = dget(exp->ex_dentry); 219 else { 220 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op; 221 dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb, 222 datap, data_left, 223 fileid_type, 224 nfsd_acceptable, exp); 225 } 226 if (dentry == NULL) 227 goto out; 228 if (IS_ERR(dentry)) { 229 if (PTR_ERR(dentry) != -EINVAL) 230 error = nfserrno(PTR_ERR(dentry)); 231 goto out; 232 } 233 #ifdef NFSD_PARANOIA 234 if (S_ISDIR(dentry->d_inode->i_mode) && 235 (dentry->d_flags & DCACHE_DISCONNECTED)) { 236 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n", 237 dentry->d_parent->d_name.name, dentry->d_name.name); 238 } 239 #endif 240 241 fhp->fh_dentry = dentry; 242 fhp->fh_export = exp; 243 nfsd_nr_verified++; 244 } else { 245 /* just rechecking permissions 246 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well) 247 */ 248 dprintk("nfsd: fh_verify - just checking\n"); 249 dentry = fhp->fh_dentry; 250 exp = fhp->fh_export; 251 } 252 cache_get(&exp->h); 253 254 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); 255 if (error) 256 goto out; 257 258 /* Finally, check access permissions. */ 259 error = nfsd_permission(exp, dentry, access); 260 261 #ifdef NFSD_PARANOIA_EXTREME 262 if (error) { 263 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n", 264 dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24)); 265 } 266 #endif 267 out: 268 if (exp && !IS_ERR(exp)) 269 exp_put(exp); 270 if (error == nfserr_stale) 271 nfsdstats.fh_stale++; 272 return error; 273 } 274 275 276 /* 277 * Compose a file handle for an NFS reply. 278 * 279 * Note that when first composed, the dentry may not yet have 280 * an inode. In this case a call to fh_update should be made 281 * before the fh goes out on the wire ... 282 */ 283 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp, 284 __u32 *datap, int *maxsize) 285 { 286 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op; 287 288 if (dentry == exp->ex_dentry) { 289 *maxsize = 0; 290 return 0; 291 } 292 293 return CALL(nop,encode_fh)(dentry, datap, maxsize, 294 !(exp->ex_flags&NFSEXP_NOSUBTREECHECK)); 295 } 296 297 /* 298 * for composing old style file handles 299 */ 300 static inline void _fh_update_old(struct dentry *dentry, 301 struct svc_export *exp, 302 struct knfsd_fh *fh) 303 { 304 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino); 305 fh->ofh_generation = dentry->d_inode->i_generation; 306 if (S_ISDIR(dentry->d_inode->i_mode) || 307 (exp->ex_flags & NFSEXP_NOSUBTREECHECK)) 308 fh->ofh_dirino = 0; 309 } 310 311 int 312 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh) 313 { 314 /* ref_fh is a reference file handle. 315 * if it is non-null, then we should compose a filehandle which is 316 * of the same version, where possible. 317 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca 318 * Then create a 32byte filehandle using nfs_fhbase_old 319 * 320 */ 321 322 u8 ref_fh_version = 0; 323 u8 ref_fh_fsid_type = 0; 324 struct inode * inode = dentry->d_inode; 325 struct dentry *parent = dentry->d_parent; 326 __u32 *datap; 327 dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev; 328 329 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n", 330 MAJOR(ex_dev), MINOR(ex_dev), 331 (long) exp->ex_dentry->d_inode->i_ino, 332 parent->d_name.name, dentry->d_name.name, 333 (inode ? inode->i_ino : 0)); 334 335 if (ref_fh) { 336 ref_fh_version = ref_fh->fh_handle.fh_version; 337 if (ref_fh_version == 0xca) 338 ref_fh_fsid_type = 0; 339 else 340 ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type; 341 if (ref_fh_fsid_type > 3) 342 ref_fh_fsid_type = 0; 343 344 /* make sure ref_fh type works for given export */ 345 if (ref_fh_fsid_type == 1 && 346 !(exp->ex_flags & NFSEXP_FSID)) { 347 /* if we don't have an fsid, we cannot provide one... */ 348 ref_fh_fsid_type = 0; 349 } 350 } else if (exp->ex_flags & NFSEXP_FSID) 351 ref_fh_fsid_type = 1; 352 353 if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) { 354 /* for newer device numbers, we must use a newer fsid format */ 355 ref_fh_version = 1; 356 ref_fh_fsid_type = 3; 357 } 358 if (old_valid_dev(ex_dev) && 359 (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3)) 360 /* must use type1 for smaller device numbers */ 361 ref_fh_fsid_type = 0; 362 363 if (ref_fh == fhp) 364 fh_put(ref_fh); 365 366 if (fhp->fh_locked || fhp->fh_dentry) { 367 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n", 368 parent->d_name.name, dentry->d_name.name); 369 } 370 if (fhp->fh_maxsize < NFS_FHSIZE) 371 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n", 372 fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name); 373 374 fhp->fh_dentry = dget(dentry); /* our internal copy */ 375 fhp->fh_export = exp; 376 cache_get(&exp->h); 377 378 if (ref_fh_version == 0xca) { 379 /* old style filehandle please */ 380 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE); 381 fhp->fh_handle.fh_size = NFS_FHSIZE; 382 fhp->fh_handle.ofh_dcookie = 0xfeebbaca; 383 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev); 384 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev; 385 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino); 386 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry)); 387 if (inode) 388 _fh_update_old(dentry, exp, &fhp->fh_handle); 389 } else { 390 int len; 391 fhp->fh_handle.fh_version = 1; 392 fhp->fh_handle.fh_auth_type = 0; 393 datap = fhp->fh_handle.fh_auth+0; 394 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type; 395 switch (ref_fh_fsid_type) { 396 case 0: 397 /* 398 * fsid_type 0: 399 * 2byte major, 2byte minor, 4byte inode 400 */ 401 mk_fsid_v0(datap, ex_dev, 402 exp->ex_dentry->d_inode->i_ino); 403 break; 404 case 1: 405 /* fsid_type 1 == 4 bytes filesystem id */ 406 mk_fsid_v1(datap, exp->ex_fsid); 407 break; 408 case 2: 409 /* 410 * fsid_type 2: 411 * 4byte major, 4byte minor, 4byte inode 412 */ 413 mk_fsid_v2(datap, ex_dev, 414 exp->ex_dentry->d_inode->i_ino); 415 break; 416 case 3: 417 /* 418 * fsid_type 3: 419 * 4byte devicenumber, 4byte inode 420 */ 421 mk_fsid_v3(datap, ex_dev, 422 exp->ex_dentry->d_inode->i_ino); 423 break; 424 } 425 len = key_len(ref_fh_fsid_type); 426 datap += len/4; 427 fhp->fh_handle.fh_size = 4 + len; 428 429 if (inode) { 430 int size = (fhp->fh_maxsize-len-4)/4; 431 fhp->fh_handle.fh_fileid_type = 432 _fh_update(dentry, exp, datap, &size); 433 fhp->fh_handle.fh_size += size*4; 434 } 435 if (fhp->fh_handle.fh_fileid_type == 255) 436 return nfserr_opnotsupp; 437 } 438 439 nfsd_nr_verified++; 440 return 0; 441 } 442 443 /* 444 * Update file handle information after changing a dentry. 445 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create 446 */ 447 int 448 fh_update(struct svc_fh *fhp) 449 { 450 struct dentry *dentry; 451 __u32 *datap; 452 453 if (!fhp->fh_dentry) 454 goto out_bad; 455 456 dentry = fhp->fh_dentry; 457 if (!dentry->d_inode) 458 goto out_negative; 459 if (fhp->fh_handle.fh_version != 1) { 460 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle); 461 } else { 462 int size; 463 if (fhp->fh_handle.fh_fileid_type != 0) 464 goto out_uptodate; 465 datap = fhp->fh_handle.fh_auth+ 466 fhp->fh_handle.fh_size/4 -1; 467 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4; 468 fhp->fh_handle.fh_fileid_type = 469 _fh_update(dentry, fhp->fh_export, datap, &size); 470 fhp->fh_handle.fh_size += size*4; 471 if (fhp->fh_handle.fh_fileid_type == 255) 472 return nfserr_opnotsupp; 473 } 474 out: 475 return 0; 476 477 out_bad: 478 printk(KERN_ERR "fh_update: fh not verified!\n"); 479 goto out; 480 out_negative: 481 printk(KERN_ERR "fh_update: %s/%s still negative!\n", 482 dentry->d_parent->d_name.name, dentry->d_name.name); 483 goto out; 484 out_uptodate: 485 printk(KERN_ERR "fh_update: %s/%s already up-to-date!\n", 486 dentry->d_parent->d_name.name, dentry->d_name.name); 487 goto out; 488 } 489 490 /* 491 * Release a file handle. 492 */ 493 void 494 fh_put(struct svc_fh *fhp) 495 { 496 struct dentry * dentry = fhp->fh_dentry; 497 struct svc_export * exp = fhp->fh_export; 498 if (dentry) { 499 fh_unlock(fhp); 500 fhp->fh_dentry = NULL; 501 dput(dentry); 502 #ifdef CONFIG_NFSD_V3 503 fhp->fh_pre_saved = 0; 504 fhp->fh_post_saved = 0; 505 #endif 506 nfsd_nr_put++; 507 } 508 if (exp) { 509 svc_export_put(&exp->h, &svc_export_cache); 510 fhp->fh_export = NULL; 511 } 512 return; 513 } 514 515 /* 516 * Shorthand for dprintk()'s 517 */ 518 char * SVCFH_fmt(struct svc_fh *fhp) 519 { 520 struct knfsd_fh *fh = &fhp->fh_handle; 521 522 static char buf[80]; 523 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x", 524 fh->fh_size, 525 fh->fh_base.fh_pad[0], 526 fh->fh_base.fh_pad[1], 527 fh->fh_base.fh_pad[2], 528 fh->fh_base.fh_pad[3], 529 fh->fh_base.fh_pad[4], 530 fh->fh_base.fh_pad[5]); 531 return buf; 532 } 533