1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * File operations used by nfsd. Some of these have been ripped from 4 * other parts of the kernel because they weren't exported, others 5 * are partial duplicates with added or changed functionality. 6 * 7 * Note that several functions dget() the dentry upon which they want 8 * to act, most notably those that create directory entries. Response 9 * dentry's are dput()'d if necessary in the release callback. 10 * So if you notice code paths that apparently fail to dput() the 11 * dentry, don't worry--they have been taken care of. 12 * 13 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de> 14 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp> 15 */ 16 17 #include <linux/fs.h> 18 #include <linux/file.h> 19 #include <linux/splice.h> 20 #include <linux/falloc.h> 21 #include <linux/fcntl.h> 22 #include <linux/namei.h> 23 #include <linux/delay.h> 24 #include <linux/fsnotify.h> 25 #include <linux/posix_acl_xattr.h> 26 #include <linux/xattr.h> 27 #include <linux/jhash.h> 28 #include <linux/ima.h> 29 #include <linux/slab.h> 30 #include <linux/uaccess.h> 31 #include <linux/exportfs.h> 32 #include <linux/writeback.h> 33 #include <linux/security.h> 34 35 #ifdef CONFIG_NFSD_V3 36 #include "xdr3.h" 37 #endif /* CONFIG_NFSD_V3 */ 38 39 #ifdef CONFIG_NFSD_V4 40 #include "../internal.h" 41 #include "acl.h" 42 #include "idmap.h" 43 #endif /* CONFIG_NFSD_V4 */ 44 45 #include "nfsd.h" 46 #include "vfs.h" 47 #include "filecache.h" 48 #include "trace.h" 49 50 #define NFSDDBG_FACILITY NFSDDBG_FILEOP 51 52 /* 53 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 54 * a mount point. 55 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged, 56 * or nfs_ok having possibly changed *dpp and *expp 57 */ 58 int 59 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp, 60 struct svc_export **expp) 61 { 62 struct svc_export *exp = *expp, *exp2 = NULL; 63 struct dentry *dentry = *dpp; 64 struct path path = {.mnt = mntget(exp->ex_path.mnt), 65 .dentry = dget(dentry)}; 66 int err = 0; 67 68 err = follow_down(&path); 69 if (err < 0) 70 goto out; 71 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && 72 nfsd_mountpoint(dentry, exp) == 2) { 73 /* This is only a mountpoint in some other namespace */ 74 path_put(&path); 75 goto out; 76 } 77 78 exp2 = rqst_exp_get_by_name(rqstp, &path); 79 if (IS_ERR(exp2)) { 80 err = PTR_ERR(exp2); 81 /* 82 * We normally allow NFS clients to continue 83 * "underneath" a mountpoint that is not exported. 84 * The exception is V4ROOT, where no traversal is ever 85 * allowed without an explicit export of the new 86 * directory. 87 */ 88 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) 89 err = 0; 90 path_put(&path); 91 goto out; 92 } 93 if (nfsd_v4client(rqstp) || 94 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { 95 /* successfully crossed mount point */ 96 /* 97 * This is subtle: path.dentry is *not* on path.mnt 98 * at this point. The only reason we are safe is that 99 * original mnt is pinned down by exp, so we should 100 * put path *before* putting exp 101 */ 102 *dpp = path.dentry; 103 path.dentry = dentry; 104 *expp = exp2; 105 exp2 = exp; 106 } 107 path_put(&path); 108 exp_put(exp2); 109 out: 110 return err; 111 } 112 113 static void follow_to_parent(struct path *path) 114 { 115 struct dentry *dp; 116 117 while (path->dentry == path->mnt->mnt_root && follow_up(path)) 118 ; 119 dp = dget_parent(path->dentry); 120 dput(path->dentry); 121 path->dentry = dp; 122 } 123 124 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) 125 { 126 struct svc_export *exp2; 127 struct path path = {.mnt = mntget((*exp)->ex_path.mnt), 128 .dentry = dget(dparent)}; 129 130 follow_to_parent(&path); 131 132 exp2 = rqst_exp_parent(rqstp, &path); 133 if (PTR_ERR(exp2) == -ENOENT) { 134 *dentryp = dget(dparent); 135 } else if (IS_ERR(exp2)) { 136 path_put(&path); 137 return PTR_ERR(exp2); 138 } else { 139 *dentryp = dget(path.dentry); 140 exp_put(*exp); 141 *exp = exp2; 142 } 143 path_put(&path); 144 return 0; 145 } 146 147 /* 148 * For nfsd purposes, we treat V4ROOT exports as though there was an 149 * export at *every* directory. 150 * We return: 151 * '1' if this dentry *must* be an export point, 152 * '2' if it might be, if there is really a mount here, and 153 * '0' if there is no chance of an export point here. 154 */ 155 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) 156 { 157 if (!d_inode(dentry)) 158 return 0; 159 if (exp->ex_flags & NFSEXP_V4ROOT) 160 return 1; 161 if (nfsd4_is_junction(dentry)) 162 return 1; 163 if (d_mountpoint(dentry)) 164 /* 165 * Might only be a mountpoint in a different namespace, 166 * but we need to check. 167 */ 168 return 2; 169 return 0; 170 } 171 172 __be32 173 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, 174 const char *name, unsigned int len, 175 struct svc_export **exp_ret, struct dentry **dentry_ret) 176 { 177 struct svc_export *exp; 178 struct dentry *dparent; 179 struct dentry *dentry; 180 int host_err; 181 182 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name); 183 184 dparent = fhp->fh_dentry; 185 exp = exp_get(fhp->fh_export); 186 187 /* Lookup the name, but don't follow links */ 188 if (isdotent(name, len)) { 189 if (len==1) 190 dentry = dget(dparent); 191 else if (dparent != exp->ex_path.dentry) 192 dentry = dget_parent(dparent); 193 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) 194 dentry = dget(dparent); /* .. == . just like at / */ 195 else { 196 /* checking mountpoint crossing is very different when stepping up */ 197 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); 198 if (host_err) 199 goto out_nfserr; 200 } 201 } else { 202 /* 203 * In the nfsd4_open() case, this may be held across 204 * subsequent open and delegation acquisition which may 205 * need to take the child's i_mutex: 206 */ 207 fh_lock_nested(fhp, I_MUTEX_PARENT); 208 dentry = lookup_one_len(name, dparent, len); 209 host_err = PTR_ERR(dentry); 210 if (IS_ERR(dentry)) 211 goto out_nfserr; 212 if (nfsd_mountpoint(dentry, exp)) { 213 /* 214 * We don't need the i_mutex after all. It's 215 * still possible we could open this (regular 216 * files can be mountpoints too), but the 217 * i_mutex is just there to prevent renames of 218 * something that we might be about to delegate, 219 * and a mountpoint won't be renamed: 220 */ 221 fh_unlock(fhp); 222 if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) { 223 dput(dentry); 224 goto out_nfserr; 225 } 226 } 227 } 228 *dentry_ret = dentry; 229 *exp_ret = exp; 230 return 0; 231 232 out_nfserr: 233 exp_put(exp); 234 return nfserrno(host_err); 235 } 236 237 /* 238 * Look up one component of a pathname. 239 * N.B. After this call _both_ fhp and resfh need an fh_put 240 * 241 * If the lookup would cross a mountpoint, and the mounted filesystem 242 * is exported to the client with NFSEXP_NOHIDE, then the lookup is 243 * accepted as it stands and the mounted directory is 244 * returned. Otherwise the covered directory is returned. 245 * NOTE: this mountpoint crossing is not supported properly by all 246 * clients and is explicitly disallowed for NFSv3 247 * NeilBrown <neilb@cse.unsw.edu.au> 248 */ 249 __be32 250 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, 251 unsigned int len, struct svc_fh *resfh) 252 { 253 struct svc_export *exp; 254 struct dentry *dentry; 255 __be32 err; 256 257 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 258 if (err) 259 return err; 260 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); 261 if (err) 262 return err; 263 err = check_nfsd_access(exp, rqstp); 264 if (err) 265 goto out; 266 /* 267 * Note: we compose the file handle now, but as the 268 * dentry may be negative, it may need to be updated. 269 */ 270 err = fh_compose(resfh, exp, dentry, fhp); 271 if (!err && d_really_is_negative(dentry)) 272 err = nfserr_noent; 273 out: 274 dput(dentry); 275 exp_put(exp); 276 return err; 277 } 278 279 /* 280 * Commit metadata changes to stable storage. 281 */ 282 static int 283 commit_inode_metadata(struct inode *inode) 284 { 285 const struct export_operations *export_ops = inode->i_sb->s_export_op; 286 287 if (export_ops->commit_metadata) 288 return export_ops->commit_metadata(inode); 289 return sync_inode_metadata(inode, 1); 290 } 291 292 static int 293 commit_metadata(struct svc_fh *fhp) 294 { 295 struct inode *inode = d_inode(fhp->fh_dentry); 296 297 if (!EX_ISSYNC(fhp->fh_export)) 298 return 0; 299 return commit_inode_metadata(inode); 300 } 301 302 /* 303 * Go over the attributes and take care of the small differences between 304 * NFS semantics and what Linux expects. 305 */ 306 static void 307 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) 308 { 309 /* sanitize the mode change */ 310 if (iap->ia_valid & ATTR_MODE) { 311 iap->ia_mode &= S_IALLUGO; 312 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); 313 } 314 315 /* Revoke setuid/setgid on chown */ 316 if (!S_ISDIR(inode->i_mode) && 317 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { 318 iap->ia_valid |= ATTR_KILL_PRIV; 319 if (iap->ia_valid & ATTR_MODE) { 320 /* we're setting mode too, just clear the s*id bits */ 321 iap->ia_mode &= ~S_ISUID; 322 if (iap->ia_mode & S_IXGRP) 323 iap->ia_mode &= ~S_ISGID; 324 } else { 325 /* set ATTR_KILL_* bits and let VFS handle it */ 326 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); 327 } 328 } 329 } 330 331 static __be32 332 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, 333 struct iattr *iap) 334 { 335 struct inode *inode = d_inode(fhp->fh_dentry); 336 int host_err; 337 338 if (iap->ia_size < inode->i_size) { 339 __be32 err; 340 341 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, 342 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); 343 if (err) 344 return err; 345 } 346 347 host_err = get_write_access(inode); 348 if (host_err) 349 goto out_nfserrno; 350 351 host_err = locks_verify_truncate(inode, NULL, iap->ia_size); 352 if (host_err) 353 goto out_put_write_access; 354 return 0; 355 356 out_put_write_access: 357 put_write_access(inode); 358 out_nfserrno: 359 return nfserrno(host_err); 360 } 361 362 /* 363 * Set various file attributes. After this call fhp needs an fh_put. 364 */ 365 __be32 366 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, 367 int check_guard, time64_t guardtime) 368 { 369 struct dentry *dentry; 370 struct inode *inode; 371 int accmode = NFSD_MAY_SATTR; 372 umode_t ftype = 0; 373 __be32 err; 374 int host_err; 375 bool get_write_count; 376 bool size_change = (iap->ia_valid & ATTR_SIZE); 377 378 if (iap->ia_valid & ATTR_SIZE) { 379 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; 380 ftype = S_IFREG; 381 } 382 383 /* 384 * If utimes(2) and friends are called with times not NULL, we should 385 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission 386 * will return EACCES, when the caller's effective UID does not match 387 * the owner of the file, and the caller is not privileged. In this 388 * situation, we should return EPERM(notify_change will return this). 389 */ 390 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) { 391 accmode |= NFSD_MAY_OWNER_OVERRIDE; 392 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET))) 393 accmode |= NFSD_MAY_WRITE; 394 } 395 396 /* Callers that do fh_verify should do the fh_want_write: */ 397 get_write_count = !fhp->fh_dentry; 398 399 /* Get inode */ 400 err = fh_verify(rqstp, fhp, ftype, accmode); 401 if (err) 402 return err; 403 if (get_write_count) { 404 host_err = fh_want_write(fhp); 405 if (host_err) 406 goto out; 407 } 408 409 dentry = fhp->fh_dentry; 410 inode = d_inode(dentry); 411 412 /* Ignore any mode updates on symlinks */ 413 if (S_ISLNK(inode->i_mode)) 414 iap->ia_valid &= ~ATTR_MODE; 415 416 if (!iap->ia_valid) 417 return 0; 418 419 nfsd_sanitize_attrs(inode, iap); 420 421 if (check_guard && guardtime != inode->i_ctime.tv_sec) 422 return nfserr_notsync; 423 424 /* 425 * The size case is special, it changes the file in addition to the 426 * attributes, and file systems don't expect it to be mixed with 427 * "random" attribute changes. We thus split out the size change 428 * into a separate call to ->setattr, and do the rest as a separate 429 * setattr call. 430 */ 431 if (size_change) { 432 err = nfsd_get_write_access(rqstp, fhp, iap); 433 if (err) 434 return err; 435 } 436 437 fh_lock(fhp); 438 if (size_change) { 439 /* 440 * RFC5661, Section 18.30.4: 441 * Changing the size of a file with SETATTR indirectly 442 * changes the time_modify and change attributes. 443 * 444 * (and similar for the older RFCs) 445 */ 446 struct iattr size_attr = { 447 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, 448 .ia_size = iap->ia_size, 449 }; 450 451 host_err = notify_change(&init_user_ns, dentry, &size_attr, NULL); 452 if (host_err) 453 goto out_unlock; 454 iap->ia_valid &= ~ATTR_SIZE; 455 456 /* 457 * Avoid the additional setattr call below if the only other 458 * attribute that the client sends is the mtime, as we update 459 * it as part of the size change above. 460 */ 461 if ((iap->ia_valid & ~ATTR_MTIME) == 0) 462 goto out_unlock; 463 } 464 465 iap->ia_valid |= ATTR_CTIME; 466 host_err = notify_change(&init_user_ns, dentry, iap, NULL); 467 468 out_unlock: 469 fh_unlock(fhp); 470 if (size_change) 471 put_write_access(inode); 472 out: 473 if (!host_err) 474 host_err = commit_metadata(fhp); 475 return nfserrno(host_err); 476 } 477 478 #if defined(CONFIG_NFSD_V4) 479 /* 480 * NFS junction information is stored in an extended attribute. 481 */ 482 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" 483 484 /** 485 * nfsd4_is_junction - Test if an object could be an NFS junction 486 * 487 * @dentry: object to test 488 * 489 * Returns 1 if "dentry" appears to contain NFS junction information. 490 * Otherwise 0 is returned. 491 */ 492 int nfsd4_is_junction(struct dentry *dentry) 493 { 494 struct inode *inode = d_inode(dentry); 495 496 if (inode == NULL) 497 return 0; 498 if (inode->i_mode & S_IXUGO) 499 return 0; 500 if (!(inode->i_mode & S_ISVTX)) 501 return 0; 502 if (vfs_getxattr(&init_user_ns, dentry, NFSD_JUNCTION_XATTR_NAME, 503 NULL, 0) <= 0) 504 return 0; 505 return 1; 506 } 507 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL 508 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, 509 struct xdr_netobj *label) 510 { 511 __be32 error; 512 int host_error; 513 struct dentry *dentry; 514 515 error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR); 516 if (error) 517 return error; 518 519 dentry = fhp->fh_dentry; 520 521 inode_lock(d_inode(dentry)); 522 host_error = security_inode_setsecctx(dentry, label->data, label->len); 523 inode_unlock(d_inode(dentry)); 524 return nfserrno(host_error); 525 } 526 #else 527 __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, 528 struct xdr_netobj *label) 529 { 530 return nfserr_notsupp; 531 } 532 #endif 533 534 __be32 nfsd4_clone_file_range(struct nfsd_file *nf_src, u64 src_pos, 535 struct nfsd_file *nf_dst, u64 dst_pos, u64 count, bool sync) 536 { 537 struct file *src = nf_src->nf_file; 538 struct file *dst = nf_dst->nf_file; 539 loff_t cloned; 540 __be32 ret = 0; 541 542 down_write(&nf_dst->nf_rwsem); 543 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0); 544 if (cloned < 0) { 545 ret = nfserrno(cloned); 546 goto out_err; 547 } 548 if (count && cloned != count) { 549 ret = nfserrno(-EINVAL); 550 goto out_err; 551 } 552 if (sync) { 553 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX; 554 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0); 555 556 if (!status) 557 status = commit_inode_metadata(file_inode(src)); 558 if (status < 0) { 559 nfsd_reset_boot_verifier(net_generic(nf_dst->nf_net, 560 nfsd_net_id)); 561 ret = nfserrno(status); 562 } 563 } 564 out_err: 565 up_write(&nf_dst->nf_rwsem); 566 return ret; 567 } 568 569 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, 570 u64 dst_pos, u64 count) 571 { 572 573 /* 574 * Limit copy to 4MB to prevent indefinitely blocking an nfsd 575 * thread and client rpc slot. The choice of 4MB is somewhat 576 * arbitrary. We might instead base this on r/wsize, or make it 577 * tunable, or use a time instead of a byte limit, or implement 578 * asynchronous copy. In theory a client could also recognize a 579 * limit like this and pipeline multiple COPY requests. 580 */ 581 count = min_t(u64, count, 1 << 22); 582 return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); 583 } 584 585 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, 586 struct file *file, loff_t offset, loff_t len, 587 int flags) 588 { 589 int error; 590 591 if (!S_ISREG(file_inode(file)->i_mode)) 592 return nfserr_inval; 593 594 error = vfs_fallocate(file, flags, offset, len); 595 if (!error) 596 error = commit_metadata(fhp); 597 598 return nfserrno(error); 599 } 600 #endif /* defined(CONFIG_NFSD_V4) */ 601 602 #ifdef CONFIG_NFSD_V3 603 /* 604 * Check server access rights to a file system object 605 */ 606 struct accessmap { 607 u32 access; 608 int how; 609 }; 610 static struct accessmap nfs3_regaccess[] = { 611 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 612 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 613 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, 614 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, 615 616 #ifdef CONFIG_NFSD_V4 617 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, 618 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, 619 { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, 620 #endif 621 622 { 0, 0 } 623 }; 624 625 static struct accessmap nfs3_diraccess[] = { 626 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 627 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, 628 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, 629 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, 630 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, 631 632 #ifdef CONFIG_NFSD_V4 633 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ }, 634 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE }, 635 { NFS4_ACCESS_XALIST, NFSD_MAY_READ }, 636 #endif 637 638 { 0, 0 } 639 }; 640 641 static struct accessmap nfs3_anyaccess[] = { 642 /* Some clients - Solaris 2.6 at least, make an access call 643 * to the server to check for access for things like /dev/null 644 * (which really, the server doesn't care about). So 645 * We provide simple access checking for them, looking 646 * mainly at mode bits, and we make sure to ignore read-only 647 * filesystem checks 648 */ 649 { NFS3_ACCESS_READ, NFSD_MAY_READ }, 650 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, 651 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 652 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, 653 654 { 0, 0 } 655 }; 656 657 __be32 658 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) 659 { 660 struct accessmap *map; 661 struct svc_export *export; 662 struct dentry *dentry; 663 u32 query, result = 0, sresult = 0; 664 __be32 error; 665 666 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); 667 if (error) 668 goto out; 669 670 export = fhp->fh_export; 671 dentry = fhp->fh_dentry; 672 673 if (d_is_reg(dentry)) 674 map = nfs3_regaccess; 675 else if (d_is_dir(dentry)) 676 map = nfs3_diraccess; 677 else 678 map = nfs3_anyaccess; 679 680 681 query = *access; 682 for (; map->access; map++) { 683 if (map->access & query) { 684 __be32 err2; 685 686 sresult |= map->access; 687 688 err2 = nfsd_permission(rqstp, export, dentry, map->how); 689 switch (err2) { 690 case nfs_ok: 691 result |= map->access; 692 break; 693 694 /* the following error codes just mean the access was not allowed, 695 * rather than an error occurred */ 696 case nfserr_rofs: 697 case nfserr_acces: 698 case nfserr_perm: 699 /* simply don't "or" in the access bit. */ 700 break; 701 default: 702 error = err2; 703 goto out; 704 } 705 } 706 } 707 *access = result; 708 if (supported) 709 *supported = sresult; 710 711 out: 712 return error; 713 } 714 #endif /* CONFIG_NFSD_V3 */ 715 716 int nfsd_open_break_lease(struct inode *inode, int access) 717 { 718 unsigned int mode; 719 720 if (access & NFSD_MAY_NOT_BREAK_LEASE) 721 return 0; 722 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; 723 return break_lease(inode, mode | O_NONBLOCK); 724 } 725 726 /* 727 * Open an existing file or directory. 728 * The may_flags argument indicates the type of open (read/write/lock) 729 * and additional flags. 730 * N.B. After this call fhp needs an fh_put 731 */ 732 static __be32 733 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 734 int may_flags, struct file **filp) 735 { 736 struct path path; 737 struct inode *inode; 738 struct file *file; 739 int flags = O_RDONLY|O_LARGEFILE; 740 __be32 err; 741 int host_err = 0; 742 743 path.mnt = fhp->fh_export->ex_path.mnt; 744 path.dentry = fhp->fh_dentry; 745 inode = d_inode(path.dentry); 746 747 /* Disallow write access to files with the append-only bit set 748 * or any access when mandatory locking enabled 749 */ 750 err = nfserr_perm; 751 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) 752 goto out; 753 /* 754 * We must ignore files (but only files) which might have mandatory 755 * locks on them because there is no way to know if the accesser has 756 * the lock. 757 */ 758 if (S_ISREG((inode)->i_mode) && mandatory_lock(inode)) 759 goto out; 760 761 if (!inode->i_fop) 762 goto out; 763 764 host_err = nfsd_open_break_lease(inode, may_flags); 765 if (host_err) /* NOMEM or WOULDBLOCK */ 766 goto out_nfserr; 767 768 if (may_flags & NFSD_MAY_WRITE) { 769 if (may_flags & NFSD_MAY_READ) 770 flags = O_RDWR|O_LARGEFILE; 771 else 772 flags = O_WRONLY|O_LARGEFILE; 773 } 774 775 file = dentry_open(&path, flags, current_cred()); 776 if (IS_ERR(file)) { 777 host_err = PTR_ERR(file); 778 goto out_nfserr; 779 } 780 781 host_err = ima_file_check(file, may_flags); 782 if (host_err) { 783 fput(file); 784 goto out_nfserr; 785 } 786 787 if (may_flags & NFSD_MAY_64BIT_COOKIE) 788 file->f_mode |= FMODE_64BITHASH; 789 else 790 file->f_mode |= FMODE_32BITHASH; 791 792 *filp = file; 793 out_nfserr: 794 err = nfserrno(host_err); 795 out: 796 return err; 797 } 798 799 __be32 800 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 801 int may_flags, struct file **filp) 802 { 803 __be32 err; 804 805 validate_process_creds(); 806 /* 807 * If we get here, then the client has already done an "open", 808 * and (hopefully) checked permission - so allow OWNER_OVERRIDE 809 * in case a chmod has now revoked permission. 810 * 811 * Arguably we should also allow the owner override for 812 * directories, but we never have and it doesn't seem to have 813 * caused anyone a problem. If we were to change this, note 814 * also that our filldir callbacks would need a variant of 815 * lookup_one_len that doesn't check permissions. 816 */ 817 if (type == S_IFREG) 818 may_flags |= NFSD_MAY_OWNER_OVERRIDE; 819 err = fh_verify(rqstp, fhp, type, may_flags); 820 if (!err) 821 err = __nfsd_open(rqstp, fhp, type, may_flags, filp); 822 validate_process_creds(); 823 return err; 824 } 825 826 __be32 827 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, 828 int may_flags, struct file **filp) 829 { 830 __be32 err; 831 832 validate_process_creds(); 833 err = __nfsd_open(rqstp, fhp, type, may_flags, filp); 834 validate_process_creds(); 835 return err; 836 } 837 838 /* 839 * Grab and keep cached pages associated with a file in the svc_rqst 840 * so that they can be passed to the network sendmsg/sendpage routines 841 * directly. They will be released after the sending has completed. 842 */ 843 static int 844 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, 845 struct splice_desc *sd) 846 { 847 struct svc_rqst *rqstp = sd->u.data; 848 struct page **pp = rqstp->rq_next_page; 849 struct page *page = buf->page; 850 size_t size; 851 852 size = sd->len; 853 854 if (rqstp->rq_res.page_len == 0) { 855 get_page(page); 856 put_page(*rqstp->rq_next_page); 857 *(rqstp->rq_next_page++) = page; 858 rqstp->rq_res.page_base = buf->offset; 859 rqstp->rq_res.page_len = size; 860 } else if (page != pp[-1]) { 861 get_page(page); 862 if (*rqstp->rq_next_page) 863 put_page(*rqstp->rq_next_page); 864 *(rqstp->rq_next_page++) = page; 865 rqstp->rq_res.page_len += size; 866 } else 867 rqstp->rq_res.page_len += size; 868 869 return size; 870 } 871 872 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, 873 struct splice_desc *sd) 874 { 875 return __splice_from_pipe(pipe, sd, nfsd_splice_actor); 876 } 877 878 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len, 879 size_t expected) 880 { 881 if (expected != 0 && len == 0) 882 return 1; 883 if (offset+len >= i_size_read(file_inode(file))) 884 return 1; 885 return 0; 886 } 887 888 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 889 struct file *file, loff_t offset, 890 unsigned long *count, u32 *eof, ssize_t host_err) 891 { 892 if (host_err >= 0) { 893 nfsd_stats_io_read_add(fhp->fh_export, host_err); 894 *eof = nfsd_eof_on_read(file, offset, host_err, *count); 895 *count = host_err; 896 fsnotify_access(file); 897 trace_nfsd_read_io_done(rqstp, fhp, offset, *count); 898 return 0; 899 } else { 900 trace_nfsd_read_err(rqstp, fhp, offset, host_err); 901 return nfserrno(host_err); 902 } 903 } 904 905 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 906 struct file *file, loff_t offset, unsigned long *count, 907 u32 *eof) 908 { 909 struct splice_desc sd = { 910 .len = 0, 911 .total_len = *count, 912 .pos = offset, 913 .u.data = rqstp, 914 }; 915 ssize_t host_err; 916 917 trace_nfsd_read_splice(rqstp, fhp, offset, *count); 918 rqstp->rq_next_page = rqstp->rq_respages + 1; 919 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor); 920 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 921 } 922 923 __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp, 924 struct file *file, loff_t offset, 925 struct kvec *vec, int vlen, unsigned long *count, 926 u32 *eof) 927 { 928 struct iov_iter iter; 929 loff_t ppos = offset; 930 ssize_t host_err; 931 932 trace_nfsd_read_vector(rqstp, fhp, offset, *count); 933 iov_iter_kvec(&iter, READ, vec, vlen, *count); 934 host_err = vfs_iter_read(file, &iter, &ppos, 0); 935 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); 936 } 937 938 /* 939 * Gathered writes: If another process is currently writing to the file, 940 * there's a high chance this is another nfsd (triggered by a bulk write 941 * from a client's biod). Rather than syncing the file with each write 942 * request, we sleep for 10 msec. 943 * 944 * I don't know if this roughly approximates C. Juszak's idea of 945 * gathered writes, but it's a nice and simple solution (IMHO), and it 946 * seems to work:-) 947 * 948 * Note: we do this only in the NFSv2 case, since v3 and higher have a 949 * better tool (separate unstable writes and commits) for solving this 950 * problem. 951 */ 952 static int wait_for_concurrent_writes(struct file *file) 953 { 954 struct inode *inode = file_inode(file); 955 static ino_t last_ino; 956 static dev_t last_dev; 957 int err = 0; 958 959 if (atomic_read(&inode->i_writecount) > 1 960 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { 961 dprintk("nfsd: write defer %d\n", task_pid_nr(current)); 962 msleep(10); 963 dprintk("nfsd: write resume %d\n", task_pid_nr(current)); 964 } 965 966 if (inode->i_state & I_DIRTY) { 967 dprintk("nfsd: write sync %d\n", task_pid_nr(current)); 968 err = vfs_fsync(file, 0); 969 } 970 last_ino = inode->i_ino; 971 last_dev = inode->i_sb->s_dev; 972 return err; 973 } 974 975 __be32 976 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, 977 loff_t offset, struct kvec *vec, int vlen, 978 unsigned long *cnt, int stable, 979 __be32 *verf) 980 { 981 struct file *file = nf->nf_file; 982 struct super_block *sb = file_inode(file)->i_sb; 983 struct svc_export *exp; 984 struct iov_iter iter; 985 __be32 nfserr; 986 int host_err; 987 int use_wgather; 988 loff_t pos = offset; 989 unsigned long exp_op_flags = 0; 990 unsigned int pflags = current->flags; 991 rwf_t flags = 0; 992 bool restore_flags = false; 993 994 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt); 995 996 if (sb->s_export_op) 997 exp_op_flags = sb->s_export_op->flags; 998 999 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) && 1000 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) { 1001 /* 1002 * We want throttling in balance_dirty_pages() 1003 * and shrink_inactive_list() to only consider 1004 * the backingdev we are writing to, so that nfs to 1005 * localhost doesn't cause nfsd to lock up due to all 1006 * the client's dirty pages or its congested queue. 1007 */ 1008 current->flags |= PF_LOCAL_THROTTLE; 1009 restore_flags = true; 1010 } 1011 1012 exp = fhp->fh_export; 1013 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); 1014 1015 if (!EX_ISSYNC(exp)) 1016 stable = NFS_UNSTABLE; 1017 1018 if (stable && !use_wgather) 1019 flags |= RWF_SYNC; 1020 1021 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt); 1022 if (flags & RWF_SYNC) { 1023 down_write(&nf->nf_rwsem); 1024 host_err = vfs_iter_write(file, &iter, &pos, flags); 1025 if (host_err < 0) 1026 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp), 1027 nfsd_net_id)); 1028 up_write(&nf->nf_rwsem); 1029 } else { 1030 down_read(&nf->nf_rwsem); 1031 if (verf) 1032 nfsd_copy_boot_verifier(verf, 1033 net_generic(SVC_NET(rqstp), 1034 nfsd_net_id)); 1035 host_err = vfs_iter_write(file, &iter, &pos, flags); 1036 up_read(&nf->nf_rwsem); 1037 } 1038 if (host_err < 0) { 1039 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp), 1040 nfsd_net_id)); 1041 goto out_nfserr; 1042 } 1043 *cnt = host_err; 1044 nfsd_stats_io_write_add(exp, *cnt); 1045 fsnotify_modify(file); 1046 1047 if (stable && use_wgather) { 1048 host_err = wait_for_concurrent_writes(file); 1049 if (host_err < 0) 1050 nfsd_reset_boot_verifier(net_generic(SVC_NET(rqstp), 1051 nfsd_net_id)); 1052 } 1053 1054 out_nfserr: 1055 if (host_err >= 0) { 1056 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt); 1057 nfserr = nfs_ok; 1058 } else { 1059 trace_nfsd_write_err(rqstp, fhp, offset, host_err); 1060 nfserr = nfserrno(host_err); 1061 } 1062 if (restore_flags) 1063 current_restore_flags(pflags, PF_LOCAL_THROTTLE); 1064 return nfserr; 1065 } 1066 1067 /* 1068 * Read data from a file. count must contain the requested read count 1069 * on entry. On return, *count contains the number of bytes actually read. 1070 * N.B. After this call fhp needs an fh_put 1071 */ 1072 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, 1073 loff_t offset, struct kvec *vec, int vlen, unsigned long *count, 1074 u32 *eof) 1075 { 1076 struct nfsd_file *nf; 1077 struct file *file; 1078 __be32 err; 1079 1080 trace_nfsd_read_start(rqstp, fhp, offset, *count); 1081 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf); 1082 if (err) 1083 return err; 1084 1085 file = nf->nf_file; 1086 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) 1087 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); 1088 else 1089 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof); 1090 1091 nfsd_file_put(nf); 1092 1093 trace_nfsd_read_done(rqstp, fhp, offset, *count); 1094 1095 return err; 1096 } 1097 1098 /* 1099 * Write data to a file. 1100 * The stable flag requests synchronous writes. 1101 * N.B. After this call fhp needs an fh_put 1102 */ 1103 __be32 1104 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 1105 struct kvec *vec, int vlen, unsigned long *cnt, int stable, 1106 __be32 *verf) 1107 { 1108 struct nfsd_file *nf; 1109 __be32 err; 1110 1111 trace_nfsd_write_start(rqstp, fhp, offset, *cnt); 1112 1113 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf); 1114 if (err) 1115 goto out; 1116 1117 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec, 1118 vlen, cnt, stable, verf); 1119 nfsd_file_put(nf); 1120 out: 1121 trace_nfsd_write_done(rqstp, fhp, offset, *cnt); 1122 return err; 1123 } 1124 1125 #ifdef CONFIG_NFSD_V3 1126 /* 1127 * Commit all pending writes to stable storage. 1128 * 1129 * Note: we only guarantee that data that lies within the range specified 1130 * by the 'offset' and 'count' parameters will be synced. 1131 * 1132 * Unfortunately we cannot lock the file to make sure we return full WCC 1133 * data to the client, as locking happens lower down in the filesystem. 1134 */ 1135 __be32 1136 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, 1137 loff_t offset, unsigned long count, __be32 *verf) 1138 { 1139 struct nfsd_file *nf; 1140 loff_t end = LLONG_MAX; 1141 __be32 err = nfserr_inval; 1142 1143 if (offset < 0) 1144 goto out; 1145 if (count != 0) { 1146 end = offset + (loff_t)count - 1; 1147 if (end < offset) 1148 goto out; 1149 } 1150 1151 err = nfsd_file_acquire(rqstp, fhp, 1152 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf); 1153 if (err) 1154 goto out; 1155 if (EX_ISSYNC(fhp->fh_export)) { 1156 int err2; 1157 1158 down_write(&nf->nf_rwsem); 1159 err2 = vfs_fsync_range(nf->nf_file, offset, end, 0); 1160 switch (err2) { 1161 case 0: 1162 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net, 1163 nfsd_net_id)); 1164 break; 1165 case -EINVAL: 1166 err = nfserr_notsupp; 1167 break; 1168 default: 1169 err = nfserrno(err2); 1170 nfsd_reset_boot_verifier(net_generic(nf->nf_net, 1171 nfsd_net_id)); 1172 } 1173 up_write(&nf->nf_rwsem); 1174 } else 1175 nfsd_copy_boot_verifier(verf, net_generic(nf->nf_net, 1176 nfsd_net_id)); 1177 1178 nfsd_file_put(nf); 1179 out: 1180 return err; 1181 } 1182 #endif /* CONFIG_NFSD_V3 */ 1183 1184 static __be32 1185 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp, 1186 struct iattr *iap) 1187 { 1188 /* 1189 * Mode has already been set earlier in create: 1190 */ 1191 iap->ia_valid &= ~ATTR_MODE; 1192 /* 1193 * Setting uid/gid works only for root. Irix appears to 1194 * send along the gid on create when it tries to implement 1195 * setgid directories via NFS: 1196 */ 1197 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) 1198 iap->ia_valid &= ~(ATTR_UID|ATTR_GID); 1199 if (iap->ia_valid) 1200 return nfsd_setattr(rqstp, resfhp, iap, 0, (time64_t)0); 1201 /* Callers expect file metadata to be committed here */ 1202 return nfserrno(commit_metadata(resfhp)); 1203 } 1204 1205 /* HPUX client sometimes creates a file in mode 000, and sets size to 0. 1206 * setting size to 0 may fail for some specific file systems by the permission 1207 * checking which requires WRITE permission but the mode is 000. 1208 * we ignore the resizing(to 0) on the just new created file, since the size is 1209 * 0 after file created. 1210 * 1211 * call this only after vfs_create() is called. 1212 * */ 1213 static void 1214 nfsd_check_ignore_resizing(struct iattr *iap) 1215 { 1216 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) 1217 iap->ia_valid &= ~ATTR_SIZE; 1218 } 1219 1220 /* The parent directory should already be locked: */ 1221 __be32 1222 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, 1223 char *fname, int flen, struct iattr *iap, 1224 int type, dev_t rdev, struct svc_fh *resfhp) 1225 { 1226 struct dentry *dentry, *dchild; 1227 struct inode *dirp; 1228 __be32 err; 1229 __be32 err2; 1230 int host_err; 1231 1232 dentry = fhp->fh_dentry; 1233 dirp = d_inode(dentry); 1234 1235 dchild = dget(resfhp->fh_dentry); 1236 if (!fhp->fh_locked) { 1237 WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n", 1238 dentry); 1239 err = nfserr_io; 1240 goto out; 1241 } 1242 1243 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); 1244 if (err) 1245 goto out; 1246 1247 if (!(iap->ia_valid & ATTR_MODE)) 1248 iap->ia_mode = 0; 1249 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; 1250 1251 if (!IS_POSIXACL(dirp)) 1252 iap->ia_mode &= ~current_umask(); 1253 1254 err = 0; 1255 host_err = 0; 1256 switch (type) { 1257 case S_IFREG: 1258 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true); 1259 if (!host_err) 1260 nfsd_check_ignore_resizing(iap); 1261 break; 1262 case S_IFDIR: 1263 host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode); 1264 if (!host_err && unlikely(d_unhashed(dchild))) { 1265 struct dentry *d; 1266 d = lookup_one_len(dchild->d_name.name, 1267 dchild->d_parent, 1268 dchild->d_name.len); 1269 if (IS_ERR(d)) { 1270 host_err = PTR_ERR(d); 1271 break; 1272 } 1273 if (unlikely(d_is_negative(d))) { 1274 dput(d); 1275 err = nfserr_serverfault; 1276 goto out; 1277 } 1278 dput(resfhp->fh_dentry); 1279 resfhp->fh_dentry = dget(d); 1280 err = fh_update(resfhp); 1281 dput(dchild); 1282 dchild = d; 1283 if (err) 1284 goto out; 1285 } 1286 break; 1287 case S_IFCHR: 1288 case S_IFBLK: 1289 case S_IFIFO: 1290 case S_IFSOCK: 1291 host_err = vfs_mknod(&init_user_ns, dirp, dchild, 1292 iap->ia_mode, rdev); 1293 break; 1294 default: 1295 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", 1296 type); 1297 host_err = -EINVAL; 1298 } 1299 if (host_err < 0) 1300 goto out_nfserr; 1301 1302 err = nfsd_create_setattr(rqstp, resfhp, iap); 1303 1304 /* 1305 * nfsd_create_setattr already committed the child. Transactional 1306 * filesystems had a chance to commit changes for both parent and 1307 * child simultaneously making the following commit_metadata a 1308 * noop. 1309 */ 1310 err2 = nfserrno(commit_metadata(fhp)); 1311 if (err2) 1312 err = err2; 1313 /* 1314 * Update the file handle to get the new inode info. 1315 */ 1316 if (!err) 1317 err = fh_update(resfhp); 1318 out: 1319 dput(dchild); 1320 return err; 1321 1322 out_nfserr: 1323 err = nfserrno(host_err); 1324 goto out; 1325 } 1326 1327 /* 1328 * Create a filesystem object (regular, directory, special). 1329 * Note that the parent directory is left locked. 1330 * 1331 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp 1332 */ 1333 __be32 1334 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1335 char *fname, int flen, struct iattr *iap, 1336 int type, dev_t rdev, struct svc_fh *resfhp) 1337 { 1338 struct dentry *dentry, *dchild = NULL; 1339 __be32 err; 1340 int host_err; 1341 1342 if (isdotent(fname, flen)) 1343 return nfserr_exist; 1344 1345 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); 1346 if (err) 1347 return err; 1348 1349 dentry = fhp->fh_dentry; 1350 1351 host_err = fh_want_write(fhp); 1352 if (host_err) 1353 return nfserrno(host_err); 1354 1355 fh_lock_nested(fhp, I_MUTEX_PARENT); 1356 dchild = lookup_one_len(fname, dentry, flen); 1357 host_err = PTR_ERR(dchild); 1358 if (IS_ERR(dchild)) 1359 return nfserrno(host_err); 1360 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1361 /* 1362 * We unconditionally drop our ref to dchild as fh_compose will have 1363 * already grabbed its own ref for it. 1364 */ 1365 dput(dchild); 1366 if (err) 1367 return err; 1368 return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type, 1369 rdev, resfhp); 1370 } 1371 1372 #ifdef CONFIG_NFSD_V3 1373 1374 /* 1375 * NFSv3 and NFSv4 version of nfsd_create 1376 */ 1377 __be32 1378 do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 1379 char *fname, int flen, struct iattr *iap, 1380 struct svc_fh *resfhp, int createmode, u32 *verifier, 1381 bool *truncp, bool *created) 1382 { 1383 struct dentry *dentry, *dchild = NULL; 1384 struct inode *dirp; 1385 __be32 err; 1386 int host_err; 1387 __u32 v_mtime=0, v_atime=0; 1388 1389 err = nfserr_perm; 1390 if (!flen) 1391 goto out; 1392 err = nfserr_exist; 1393 if (isdotent(fname, flen)) 1394 goto out; 1395 if (!(iap->ia_valid & ATTR_MODE)) 1396 iap->ia_mode = 0; 1397 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); 1398 if (err) 1399 goto out; 1400 1401 dentry = fhp->fh_dentry; 1402 dirp = d_inode(dentry); 1403 1404 host_err = fh_want_write(fhp); 1405 if (host_err) 1406 goto out_nfserr; 1407 1408 fh_lock_nested(fhp, I_MUTEX_PARENT); 1409 1410 /* 1411 * Compose the response file handle. 1412 */ 1413 dchild = lookup_one_len(fname, dentry, flen); 1414 host_err = PTR_ERR(dchild); 1415 if (IS_ERR(dchild)) 1416 goto out_nfserr; 1417 1418 /* If file doesn't exist, check for permissions to create one */ 1419 if (d_really_is_negative(dchild)) { 1420 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1421 if (err) 1422 goto out; 1423 } 1424 1425 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); 1426 if (err) 1427 goto out; 1428 1429 if (nfsd_create_is_exclusive(createmode)) { 1430 /* solaris7 gets confused (bugid 4218508) if these have 1431 * the high bit set, so just clear the high bits. If this is 1432 * ever changed to use different attrs for storing the 1433 * verifier, then do_open_lookup() will also need to be fixed 1434 * accordingly. 1435 */ 1436 v_mtime = verifier[0]&0x7fffffff; 1437 v_atime = verifier[1]&0x7fffffff; 1438 } 1439 1440 if (d_really_is_positive(dchild)) { 1441 err = 0; 1442 1443 switch (createmode) { 1444 case NFS3_CREATE_UNCHECKED: 1445 if (! d_is_reg(dchild)) 1446 goto out; 1447 else if (truncp) { 1448 /* in nfsv4, we need to treat this case a little 1449 * differently. we don't want to truncate the 1450 * file now; this would be wrong if the OPEN 1451 * fails for some other reason. furthermore, 1452 * if the size is nonzero, we should ignore it 1453 * according to spec! 1454 */ 1455 *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size; 1456 } 1457 else { 1458 iap->ia_valid &= ATTR_SIZE; 1459 goto set_attr; 1460 } 1461 break; 1462 case NFS3_CREATE_EXCLUSIVE: 1463 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime 1464 && d_inode(dchild)->i_atime.tv_sec == v_atime 1465 && d_inode(dchild)->i_size == 0 ) { 1466 if (created) 1467 *created = true; 1468 break; 1469 } 1470 fallthrough; 1471 case NFS4_CREATE_EXCLUSIVE4_1: 1472 if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime 1473 && d_inode(dchild)->i_atime.tv_sec == v_atime 1474 && d_inode(dchild)->i_size == 0 ) { 1475 if (created) 1476 *created = true; 1477 goto set_attr; 1478 } 1479 fallthrough; 1480 case NFS3_CREATE_GUARDED: 1481 err = nfserr_exist; 1482 } 1483 fh_drop_write(fhp); 1484 goto out; 1485 } 1486 1487 if (!IS_POSIXACL(dirp)) 1488 iap->ia_mode &= ~current_umask(); 1489 1490 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true); 1491 if (host_err < 0) { 1492 fh_drop_write(fhp); 1493 goto out_nfserr; 1494 } 1495 if (created) 1496 *created = true; 1497 1498 nfsd_check_ignore_resizing(iap); 1499 1500 if (nfsd_create_is_exclusive(createmode)) { 1501 /* Cram the verifier into atime/mtime */ 1502 iap->ia_valid = ATTR_MTIME|ATTR_ATIME 1503 | ATTR_MTIME_SET|ATTR_ATIME_SET; 1504 /* XXX someone who knows this better please fix it for nsec */ 1505 iap->ia_mtime.tv_sec = v_mtime; 1506 iap->ia_atime.tv_sec = v_atime; 1507 iap->ia_mtime.tv_nsec = 0; 1508 iap->ia_atime.tv_nsec = 0; 1509 } 1510 1511 set_attr: 1512 err = nfsd_create_setattr(rqstp, resfhp, iap); 1513 1514 /* 1515 * nfsd_create_setattr already committed the child 1516 * (and possibly also the parent). 1517 */ 1518 if (!err) 1519 err = nfserrno(commit_metadata(fhp)); 1520 1521 /* 1522 * Update the filehandle to get the new inode info. 1523 */ 1524 if (!err) 1525 err = fh_update(resfhp); 1526 1527 out: 1528 fh_unlock(fhp); 1529 if (dchild && !IS_ERR(dchild)) 1530 dput(dchild); 1531 fh_drop_write(fhp); 1532 return err; 1533 1534 out_nfserr: 1535 err = nfserrno(host_err); 1536 goto out; 1537 } 1538 #endif /* CONFIG_NFSD_V3 */ 1539 1540 /* 1541 * Read a symlink. On entry, *lenp must contain the maximum path length that 1542 * fits into the buffer. On return, it contains the true length. 1543 * N.B. After this call fhp needs an fh_put 1544 */ 1545 __be32 1546 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) 1547 { 1548 __be32 err; 1549 const char *link; 1550 struct path path; 1551 DEFINE_DELAYED_CALL(done); 1552 int len; 1553 1554 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); 1555 if (unlikely(err)) 1556 return err; 1557 1558 path.mnt = fhp->fh_export->ex_path.mnt; 1559 path.dentry = fhp->fh_dentry; 1560 1561 if (unlikely(!d_is_symlink(path.dentry))) 1562 return nfserr_inval; 1563 1564 touch_atime(&path); 1565 1566 link = vfs_get_link(path.dentry, &done); 1567 if (IS_ERR(link)) 1568 return nfserrno(PTR_ERR(link)); 1569 1570 len = strlen(link); 1571 if (len < *lenp) 1572 *lenp = len; 1573 memcpy(buf, link, *lenp); 1574 do_delayed_call(&done); 1575 return 0; 1576 } 1577 1578 /* 1579 * Create a symlink and look up its inode 1580 * N.B. After this call _both_ fhp and resfhp need an fh_put 1581 */ 1582 __be32 1583 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 1584 char *fname, int flen, 1585 char *path, 1586 struct svc_fh *resfhp) 1587 { 1588 struct dentry *dentry, *dnew; 1589 __be32 err, cerr; 1590 int host_err; 1591 1592 err = nfserr_noent; 1593 if (!flen || path[0] == '\0') 1594 goto out; 1595 err = nfserr_exist; 1596 if (isdotent(fname, flen)) 1597 goto out; 1598 1599 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); 1600 if (err) 1601 goto out; 1602 1603 host_err = fh_want_write(fhp); 1604 if (host_err) 1605 goto out_nfserr; 1606 1607 fh_lock(fhp); 1608 dentry = fhp->fh_dentry; 1609 dnew = lookup_one_len(fname, dentry, flen); 1610 host_err = PTR_ERR(dnew); 1611 if (IS_ERR(dnew)) 1612 goto out_nfserr; 1613 1614 host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path); 1615 err = nfserrno(host_err); 1616 if (!err) 1617 err = nfserrno(commit_metadata(fhp)); 1618 fh_unlock(fhp); 1619 1620 fh_drop_write(fhp); 1621 1622 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); 1623 dput(dnew); 1624 if (err==0) err = cerr; 1625 out: 1626 return err; 1627 1628 out_nfserr: 1629 err = nfserrno(host_err); 1630 goto out; 1631 } 1632 1633 /* 1634 * Create a hardlink 1635 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1636 */ 1637 __be32 1638 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 1639 char *name, int len, struct svc_fh *tfhp) 1640 { 1641 struct dentry *ddir, *dnew, *dold; 1642 struct inode *dirp; 1643 __be32 err; 1644 int host_err; 1645 1646 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); 1647 if (err) 1648 goto out; 1649 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); 1650 if (err) 1651 goto out; 1652 err = nfserr_isdir; 1653 if (d_is_dir(tfhp->fh_dentry)) 1654 goto out; 1655 err = nfserr_perm; 1656 if (!len) 1657 goto out; 1658 err = nfserr_exist; 1659 if (isdotent(name, len)) 1660 goto out; 1661 1662 host_err = fh_want_write(tfhp); 1663 if (host_err) { 1664 err = nfserrno(host_err); 1665 goto out; 1666 } 1667 1668 fh_lock_nested(ffhp, I_MUTEX_PARENT); 1669 ddir = ffhp->fh_dentry; 1670 dirp = d_inode(ddir); 1671 1672 dnew = lookup_one_len(name, ddir, len); 1673 host_err = PTR_ERR(dnew); 1674 if (IS_ERR(dnew)) 1675 goto out_nfserr; 1676 1677 dold = tfhp->fh_dentry; 1678 1679 err = nfserr_noent; 1680 if (d_really_is_negative(dold)) 1681 goto out_dput; 1682 host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL); 1683 if (!host_err) { 1684 err = nfserrno(commit_metadata(ffhp)); 1685 if (!err) 1686 err = nfserrno(commit_metadata(tfhp)); 1687 } else { 1688 if (host_err == -EXDEV && rqstp->rq_vers == 2) 1689 err = nfserr_acces; 1690 else 1691 err = nfserrno(host_err); 1692 } 1693 out_dput: 1694 dput(dnew); 1695 out_unlock: 1696 fh_unlock(ffhp); 1697 fh_drop_write(tfhp); 1698 out: 1699 return err; 1700 1701 out_nfserr: 1702 err = nfserrno(host_err); 1703 goto out_unlock; 1704 } 1705 1706 static void 1707 nfsd_close_cached_files(struct dentry *dentry) 1708 { 1709 struct inode *inode = d_inode(dentry); 1710 1711 if (inode && S_ISREG(inode->i_mode)) 1712 nfsd_file_close_inode_sync(inode); 1713 } 1714 1715 static bool 1716 nfsd_has_cached_files(struct dentry *dentry) 1717 { 1718 bool ret = false; 1719 struct inode *inode = d_inode(dentry); 1720 1721 if (inode && S_ISREG(inode->i_mode)) 1722 ret = nfsd_file_is_cached(inode); 1723 return ret; 1724 } 1725 1726 /* 1727 * Rename a file 1728 * N.B. After this call _both_ ffhp and tfhp need an fh_put 1729 */ 1730 __be32 1731 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 1732 struct svc_fh *tfhp, char *tname, int tlen) 1733 { 1734 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; 1735 struct inode *fdir, *tdir; 1736 __be32 err; 1737 int host_err; 1738 bool close_cached = false; 1739 1740 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); 1741 if (err) 1742 goto out; 1743 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); 1744 if (err) 1745 goto out; 1746 1747 fdentry = ffhp->fh_dentry; 1748 fdir = d_inode(fdentry); 1749 1750 tdentry = tfhp->fh_dentry; 1751 tdir = d_inode(tdentry); 1752 1753 err = nfserr_perm; 1754 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) 1755 goto out; 1756 1757 retry: 1758 host_err = fh_want_write(ffhp); 1759 if (host_err) { 1760 err = nfserrno(host_err); 1761 goto out; 1762 } 1763 1764 /* cannot use fh_lock as we need deadlock protective ordering 1765 * so do it by hand */ 1766 trap = lock_rename(tdentry, fdentry); 1767 ffhp->fh_locked = tfhp->fh_locked = true; 1768 fill_pre_wcc(ffhp); 1769 fill_pre_wcc(tfhp); 1770 1771 odentry = lookup_one_len(fname, fdentry, flen); 1772 host_err = PTR_ERR(odentry); 1773 if (IS_ERR(odentry)) 1774 goto out_nfserr; 1775 1776 host_err = -ENOENT; 1777 if (d_really_is_negative(odentry)) 1778 goto out_dput_old; 1779 host_err = -EINVAL; 1780 if (odentry == trap) 1781 goto out_dput_old; 1782 1783 ndentry = lookup_one_len(tname, tdentry, tlen); 1784 host_err = PTR_ERR(ndentry); 1785 if (IS_ERR(ndentry)) 1786 goto out_dput_old; 1787 host_err = -ENOTEMPTY; 1788 if (ndentry == trap) 1789 goto out_dput_new; 1790 1791 host_err = -EXDEV; 1792 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) 1793 goto out_dput_new; 1794 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) 1795 goto out_dput_new; 1796 1797 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && 1798 nfsd_has_cached_files(ndentry)) { 1799 close_cached = true; 1800 goto out_dput_old; 1801 } else { 1802 struct renamedata rd = { 1803 .old_mnt_userns = &init_user_ns, 1804 .old_dir = fdir, 1805 .old_dentry = odentry, 1806 .new_mnt_userns = &init_user_ns, 1807 .new_dir = tdir, 1808 .new_dentry = ndentry, 1809 }; 1810 host_err = vfs_rename(&rd); 1811 if (!host_err) { 1812 host_err = commit_metadata(tfhp); 1813 if (!host_err) 1814 host_err = commit_metadata(ffhp); 1815 } 1816 } 1817 out_dput_new: 1818 dput(ndentry); 1819 out_dput_old: 1820 dput(odentry); 1821 out_nfserr: 1822 err = nfserrno(host_err); 1823 /* 1824 * We cannot rely on fh_unlock on the two filehandles, 1825 * as that would do the wrong thing if the two directories 1826 * were the same, so again we do it by hand. 1827 */ 1828 if (!close_cached) { 1829 fill_post_wcc(ffhp); 1830 fill_post_wcc(tfhp); 1831 } 1832 unlock_rename(tdentry, fdentry); 1833 ffhp->fh_locked = tfhp->fh_locked = false; 1834 fh_drop_write(ffhp); 1835 1836 /* 1837 * If the target dentry has cached open files, then we need to try to 1838 * close them prior to doing the rename. Flushing delayed fput 1839 * shouldn't be done with locks held however, so we delay it until this 1840 * point and then reattempt the whole shebang. 1841 */ 1842 if (close_cached) { 1843 close_cached = false; 1844 nfsd_close_cached_files(ndentry); 1845 dput(ndentry); 1846 goto retry; 1847 } 1848 out: 1849 return err; 1850 } 1851 1852 /* 1853 * Unlink a file or directory 1854 * N.B. After this call fhp needs an fh_put 1855 */ 1856 __be32 1857 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 1858 char *fname, int flen) 1859 { 1860 struct dentry *dentry, *rdentry; 1861 struct inode *dirp; 1862 __be32 err; 1863 int host_err; 1864 1865 err = nfserr_acces; 1866 if (!flen || isdotent(fname, flen)) 1867 goto out; 1868 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); 1869 if (err) 1870 goto out; 1871 1872 host_err = fh_want_write(fhp); 1873 if (host_err) 1874 goto out_nfserr; 1875 1876 fh_lock_nested(fhp, I_MUTEX_PARENT); 1877 dentry = fhp->fh_dentry; 1878 dirp = d_inode(dentry); 1879 1880 rdentry = lookup_one_len(fname, dentry, flen); 1881 host_err = PTR_ERR(rdentry); 1882 if (IS_ERR(rdentry)) 1883 goto out_drop_write; 1884 1885 if (d_really_is_negative(rdentry)) { 1886 dput(rdentry); 1887 host_err = -ENOENT; 1888 goto out_drop_write; 1889 } 1890 1891 if (!type) 1892 type = d_inode(rdentry)->i_mode & S_IFMT; 1893 1894 if (type != S_IFDIR) { 1895 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) 1896 nfsd_close_cached_files(rdentry); 1897 host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL); 1898 } else { 1899 host_err = vfs_rmdir(&init_user_ns, dirp, rdentry); 1900 } 1901 1902 if (!host_err) 1903 host_err = commit_metadata(fhp); 1904 dput(rdentry); 1905 1906 out_drop_write: 1907 fh_drop_write(fhp); 1908 out_nfserr: 1909 if (host_err == -EBUSY) { 1910 /* name is mounted-on. There is no perfect 1911 * error status. 1912 */ 1913 if (nfsd_v4client(rqstp)) 1914 err = nfserr_file_open; 1915 else 1916 err = nfserr_acces; 1917 } else { 1918 err = nfserrno(host_err); 1919 } 1920 out: 1921 return err; 1922 } 1923 1924 /* 1925 * We do this buffering because we must not call back into the file 1926 * system's ->lookup() method from the filldir callback. That may well 1927 * deadlock a number of file systems. 1928 * 1929 * This is based heavily on the implementation of same in XFS. 1930 */ 1931 struct buffered_dirent { 1932 u64 ino; 1933 loff_t offset; 1934 int namlen; 1935 unsigned int d_type; 1936 char name[]; 1937 }; 1938 1939 struct readdir_data { 1940 struct dir_context ctx; 1941 char *dirent; 1942 size_t used; 1943 int full; 1944 }; 1945 1946 static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name, 1947 int namlen, loff_t offset, u64 ino, 1948 unsigned int d_type) 1949 { 1950 struct readdir_data *buf = 1951 container_of(ctx, struct readdir_data, ctx); 1952 struct buffered_dirent *de = (void *)(buf->dirent + buf->used); 1953 unsigned int reclen; 1954 1955 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); 1956 if (buf->used + reclen > PAGE_SIZE) { 1957 buf->full = 1; 1958 return -EINVAL; 1959 } 1960 1961 de->namlen = namlen; 1962 de->offset = offset; 1963 de->ino = ino; 1964 de->d_type = d_type; 1965 memcpy(de->name, name, namlen); 1966 buf->used += reclen; 1967 1968 return 0; 1969 } 1970 1971 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp, 1972 nfsd_filldir_t func, struct readdir_cd *cdp, 1973 loff_t *offsetp) 1974 { 1975 struct buffered_dirent *de; 1976 int host_err; 1977 int size; 1978 loff_t offset; 1979 struct readdir_data buf = { 1980 .ctx.actor = nfsd_buffered_filldir, 1981 .dirent = (void *)__get_free_page(GFP_KERNEL) 1982 }; 1983 1984 if (!buf.dirent) 1985 return nfserrno(-ENOMEM); 1986 1987 offset = *offsetp; 1988 1989 while (1) { 1990 unsigned int reclen; 1991 1992 cdp->err = nfserr_eof; /* will be cleared on successful read */ 1993 buf.used = 0; 1994 buf.full = 0; 1995 1996 host_err = iterate_dir(file, &buf.ctx); 1997 if (buf.full) 1998 host_err = 0; 1999 2000 if (host_err < 0) 2001 break; 2002 2003 size = buf.used; 2004 2005 if (!size) 2006 break; 2007 2008 de = (struct buffered_dirent *)buf.dirent; 2009 while (size > 0) { 2010 offset = de->offset; 2011 2012 if (func(cdp, de->name, de->namlen, de->offset, 2013 de->ino, de->d_type)) 2014 break; 2015 2016 if (cdp->err != nfs_ok) 2017 break; 2018 2019 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen); 2020 2021 reclen = ALIGN(sizeof(*de) + de->namlen, 2022 sizeof(u64)); 2023 size -= reclen; 2024 de = (struct buffered_dirent *)((char *)de + reclen); 2025 } 2026 if (size > 0) /* We bailed out early */ 2027 break; 2028 2029 offset = vfs_llseek(file, 0, SEEK_CUR); 2030 } 2031 2032 free_page((unsigned long)(buf.dirent)); 2033 2034 if (host_err) 2035 return nfserrno(host_err); 2036 2037 *offsetp = offset; 2038 return cdp->err; 2039 } 2040 2041 /* 2042 * Read entries from a directory. 2043 * The NFSv3/4 verifier we ignore for now. 2044 */ 2045 __be32 2046 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, 2047 struct readdir_cd *cdp, nfsd_filldir_t func) 2048 { 2049 __be32 err; 2050 struct file *file; 2051 loff_t offset = *offsetp; 2052 int may_flags = NFSD_MAY_READ; 2053 2054 /* NFSv2 only supports 32 bit cookies */ 2055 if (rqstp->rq_vers > 2) 2056 may_flags |= NFSD_MAY_64BIT_COOKIE; 2057 2058 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); 2059 if (err) 2060 goto out; 2061 2062 offset = vfs_llseek(file, offset, SEEK_SET); 2063 if (offset < 0) { 2064 err = nfserrno((int)offset); 2065 goto out_close; 2066 } 2067 2068 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp); 2069 2070 if (err == nfserr_eof || err == nfserr_toosmall) 2071 err = nfs_ok; /* can still be found in ->err */ 2072 out_close: 2073 fput(file); 2074 out: 2075 return err; 2076 } 2077 2078 /* 2079 * Get file system stats 2080 * N.B. After this call fhp needs an fh_put 2081 */ 2082 __be32 2083 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) 2084 { 2085 __be32 err; 2086 2087 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); 2088 if (!err) { 2089 struct path path = { 2090 .mnt = fhp->fh_export->ex_path.mnt, 2091 .dentry = fhp->fh_dentry, 2092 }; 2093 if (vfs_statfs(&path, stat)) 2094 err = nfserr_io; 2095 } 2096 return err; 2097 } 2098 2099 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) 2100 { 2101 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; 2102 } 2103 2104 #ifdef CONFIG_NFSD_V4 2105 /* 2106 * Helper function to translate error numbers. In the case of xattr operations, 2107 * some error codes need to be translated outside of the standard translations. 2108 * 2109 * ENODATA needs to be translated to nfserr_noxattr. 2110 * E2BIG to nfserr_xattr2big. 2111 * 2112 * Additionally, vfs_listxattr can return -ERANGE. This means that the 2113 * file has too many extended attributes to retrieve inside an 2114 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation: 2115 * filesystems will allow the adding of extended attributes until they hit 2116 * their own internal limit. This limit may be larger than XATTR_LIST_MAX. 2117 * So, at that point, the attributes are present and valid, but can't 2118 * be retrieved using listxattr, since the upper level xattr code enforces 2119 * the XATTR_LIST_MAX limit. 2120 * 2121 * This bug means that we need to deal with listxattr returning -ERANGE. The 2122 * best mapping is to return TOOSMALL. 2123 */ 2124 static __be32 2125 nfsd_xattr_errno(int err) 2126 { 2127 switch (err) { 2128 case -ENODATA: 2129 return nfserr_noxattr; 2130 case -E2BIG: 2131 return nfserr_xattr2big; 2132 case -ERANGE: 2133 return nfserr_toosmall; 2134 } 2135 return nfserrno(err); 2136 } 2137 2138 /* 2139 * Retrieve the specified user extended attribute. To avoid always 2140 * having to allocate the maximum size (since we are not getting 2141 * a maximum size from the RPC), do a probe + alloc. Hold a reader 2142 * lock on i_rwsem to prevent the extended attribute from changing 2143 * size while we're doing this. 2144 */ 2145 __be32 2146 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2147 void **bufp, int *lenp) 2148 { 2149 ssize_t len; 2150 __be32 err; 2151 char *buf; 2152 struct inode *inode; 2153 struct dentry *dentry; 2154 2155 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2156 if (err) 2157 return err; 2158 2159 err = nfs_ok; 2160 dentry = fhp->fh_dentry; 2161 inode = d_inode(dentry); 2162 2163 inode_lock_shared(inode); 2164 2165 len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0); 2166 2167 /* 2168 * Zero-length attribute, just return. 2169 */ 2170 if (len == 0) { 2171 *bufp = NULL; 2172 *lenp = 0; 2173 goto out; 2174 } 2175 2176 if (len < 0) { 2177 err = nfsd_xattr_errno(len); 2178 goto out; 2179 } 2180 2181 if (len > *lenp) { 2182 err = nfserr_toosmall; 2183 goto out; 2184 } 2185 2186 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); 2187 if (buf == NULL) { 2188 err = nfserr_jukebox; 2189 goto out; 2190 } 2191 2192 len = vfs_getxattr(&init_user_ns, dentry, name, buf, len); 2193 if (len <= 0) { 2194 kvfree(buf); 2195 buf = NULL; 2196 err = nfsd_xattr_errno(len); 2197 } 2198 2199 *lenp = len; 2200 *bufp = buf; 2201 2202 out: 2203 inode_unlock_shared(inode); 2204 2205 return err; 2206 } 2207 2208 /* 2209 * Retrieve the xattr names. Since we can't know how many are 2210 * user extended attributes, we must get all attributes here, 2211 * and have the XDR encode filter out the "user." ones. 2212 * 2213 * While this could always just allocate an XATTR_LIST_MAX 2214 * buffer, that's a waste, so do a probe + allocate. To 2215 * avoid any changes between the probe and allocate, wrap 2216 * this in inode_lock. 2217 */ 2218 __be32 2219 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, 2220 int *lenp) 2221 { 2222 ssize_t len; 2223 __be32 err; 2224 char *buf; 2225 struct inode *inode; 2226 struct dentry *dentry; 2227 2228 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); 2229 if (err) 2230 return err; 2231 2232 dentry = fhp->fh_dentry; 2233 inode = d_inode(dentry); 2234 *lenp = 0; 2235 2236 inode_lock_shared(inode); 2237 2238 len = vfs_listxattr(dentry, NULL, 0); 2239 if (len <= 0) { 2240 err = nfsd_xattr_errno(len); 2241 goto out; 2242 } 2243 2244 if (len > XATTR_LIST_MAX) { 2245 err = nfserr_xattr2big; 2246 goto out; 2247 } 2248 2249 /* 2250 * We're holding i_rwsem - use GFP_NOFS. 2251 */ 2252 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); 2253 if (buf == NULL) { 2254 err = nfserr_jukebox; 2255 goto out; 2256 } 2257 2258 len = vfs_listxattr(dentry, buf, len); 2259 if (len <= 0) { 2260 kvfree(buf); 2261 err = nfsd_xattr_errno(len); 2262 goto out; 2263 } 2264 2265 *lenp = len; 2266 *bufp = buf; 2267 2268 err = nfs_ok; 2269 out: 2270 inode_unlock_shared(inode); 2271 2272 return err; 2273 } 2274 2275 /* 2276 * Removexattr and setxattr need to call fh_lock to both lock the inode 2277 * and set the change attribute. Since the top-level vfs_removexattr 2278 * and vfs_setxattr calls already do their own inode_lock calls, call 2279 * the _locked variant. Pass in a NULL pointer for delegated_inode, 2280 * and let the client deal with NFS4ERR_DELAY (same as with e.g. 2281 * setattr and remove). 2282 */ 2283 __be32 2284 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name) 2285 { 2286 __be32 err; 2287 int ret; 2288 2289 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2290 if (err) 2291 return err; 2292 2293 ret = fh_want_write(fhp); 2294 if (ret) 2295 return nfserrno(ret); 2296 2297 fh_lock(fhp); 2298 2299 ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry, 2300 name, NULL); 2301 2302 fh_unlock(fhp); 2303 fh_drop_write(fhp); 2304 2305 return nfsd_xattr_errno(ret); 2306 } 2307 2308 __be32 2309 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, 2310 void *buf, u32 len, u32 flags) 2311 { 2312 __be32 err; 2313 int ret; 2314 2315 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE); 2316 if (err) 2317 return err; 2318 2319 ret = fh_want_write(fhp); 2320 if (ret) 2321 return nfserrno(ret); 2322 fh_lock(fhp); 2323 2324 ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf, 2325 len, flags, NULL); 2326 2327 fh_unlock(fhp); 2328 fh_drop_write(fhp); 2329 2330 return nfsd_xattr_errno(ret); 2331 } 2332 #endif 2333 2334 /* 2335 * Check for a user's access permissions to this inode. 2336 */ 2337 __be32 2338 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, 2339 struct dentry *dentry, int acc) 2340 { 2341 struct inode *inode = d_inode(dentry); 2342 int err; 2343 2344 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) 2345 return 0; 2346 #if 0 2347 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", 2348 acc, 2349 (acc & NFSD_MAY_READ)? " read" : "", 2350 (acc & NFSD_MAY_WRITE)? " write" : "", 2351 (acc & NFSD_MAY_EXEC)? " exec" : "", 2352 (acc & NFSD_MAY_SATTR)? " sattr" : "", 2353 (acc & NFSD_MAY_TRUNC)? " trunc" : "", 2354 (acc & NFSD_MAY_LOCK)? " lock" : "", 2355 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", 2356 inode->i_mode, 2357 IS_IMMUTABLE(inode)? " immut" : "", 2358 IS_APPEND(inode)? " append" : "", 2359 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); 2360 dprintk(" owner %d/%d user %d/%d\n", 2361 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); 2362 #endif 2363 2364 /* Normally we reject any write/sattr etc access on a read-only file 2365 * system. But if it is IRIX doing check on write-access for a 2366 * device special file, we ignore rofs. 2367 */ 2368 if (!(acc & NFSD_MAY_LOCAL_ACCESS)) 2369 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { 2370 if (exp_rdonly(rqstp, exp) || 2371 __mnt_is_readonly(exp->ex_path.mnt)) 2372 return nfserr_rofs; 2373 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) 2374 return nfserr_perm; 2375 } 2376 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) 2377 return nfserr_perm; 2378 2379 if (acc & NFSD_MAY_LOCK) { 2380 /* If we cannot rely on authentication in NLM requests, 2381 * just allow locks, otherwise require read permission, or 2382 * ownership 2383 */ 2384 if (exp->ex_flags & NFSEXP_NOAUTHNLM) 2385 return 0; 2386 else 2387 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; 2388 } 2389 /* 2390 * The file owner always gets access permission for accesses that 2391 * would normally be checked at open time. This is to make 2392 * file access work even when the client has done a fchmod(fd, 0). 2393 * 2394 * However, `cp foo bar' should fail nevertheless when bar is 2395 * readonly. A sensible way to do this might be to reject all 2396 * attempts to truncate a read-only file, because a creat() call 2397 * always implies file truncation. 2398 * ... but this isn't really fair. A process may reasonably call 2399 * ftruncate on an open file descriptor on a file with perm 000. 2400 * We must trust the client to do permission checking - using "ACCESS" 2401 * with NFSv3. 2402 */ 2403 if ((acc & NFSD_MAY_OWNER_OVERRIDE) && 2404 uid_eq(inode->i_uid, current_fsuid())) 2405 return 0; 2406 2407 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ 2408 err = inode_permission(&init_user_ns, inode, 2409 acc & (MAY_READ | MAY_WRITE | MAY_EXEC)); 2410 2411 /* Allow read access to binaries even when mode 111 */ 2412 if (err == -EACCES && S_ISREG(inode->i_mode) && 2413 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || 2414 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) 2415 err = inode_permission(&init_user_ns, inode, MAY_EXEC); 2416 2417 return err? nfserrno(err) : 0; 2418 } 2419