1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/fs/open.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 */ 7 8 #include <linux/string.h> 9 #include <linux/mm.h> 10 #include <linux/file.h> 11 #include <linux/fdtable.h> 12 #include <linux/fsnotify.h> 13 #include <linux/module.h> 14 #include <linux/tty.h> 15 #include <linux/namei.h> 16 #include <linux/backing-dev.h> 17 #include <linux/capability.h> 18 #include <linux/securebits.h> 19 #include <linux/security.h> 20 #include <linux/mount.h> 21 #include <linux/fcntl.h> 22 #include <linux/slab.h> 23 #include <linux/uaccess.h> 24 #include <linux/fs.h> 25 #include <linux/personality.h> 26 #include <linux/pagemap.h> 27 #include <linux/syscalls.h> 28 #include <linux/rcupdate.h> 29 #include <linux/audit.h> 30 #include <linux/falloc.h> 31 #include <linux/fs_struct.h> 32 #include <linux/ima.h> 33 #include <linux/dnotify.h> 34 #include <linux/compat.h> 35 #include <linux/mnt_idmapping.h> 36 #include <linux/filelock.h> 37 38 #include "internal.h" 39 40 int do_truncate(struct mnt_idmap *idmap, struct dentry *dentry, 41 loff_t length, unsigned int time_attrs, struct file *filp) 42 { 43 int ret; 44 struct iattr newattrs; 45 46 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ 47 if (length < 0) 48 return -EINVAL; 49 50 newattrs.ia_size = length; 51 newattrs.ia_valid = ATTR_SIZE | time_attrs; 52 if (filp) { 53 newattrs.ia_file = filp; 54 newattrs.ia_valid |= ATTR_FILE; 55 } 56 57 /* Remove suid, sgid, and file capabilities on truncate too */ 58 ret = dentry_needs_remove_privs(idmap, dentry); 59 if (ret < 0) 60 return ret; 61 if (ret) 62 newattrs.ia_valid |= ret | ATTR_FORCE; 63 64 inode_lock(dentry->d_inode); 65 /* Note any delegations or leases have already been broken: */ 66 ret = notify_change(idmap, dentry, &newattrs, NULL); 67 inode_unlock(dentry->d_inode); 68 return ret; 69 } 70 71 long vfs_truncate(const struct path *path, loff_t length) 72 { 73 struct mnt_idmap *idmap; 74 struct inode *inode; 75 long error; 76 77 inode = path->dentry->d_inode; 78 79 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ 80 if (S_ISDIR(inode->i_mode)) 81 return -EISDIR; 82 if (!S_ISREG(inode->i_mode)) 83 return -EINVAL; 84 85 error = mnt_want_write(path->mnt); 86 if (error) 87 goto out; 88 89 idmap = mnt_idmap(path->mnt); 90 error = inode_permission(idmap, inode, MAY_WRITE); 91 if (error) 92 goto mnt_drop_write_and_out; 93 94 error = -EPERM; 95 if (IS_APPEND(inode)) 96 goto mnt_drop_write_and_out; 97 98 error = get_write_access(inode); 99 if (error) 100 goto mnt_drop_write_and_out; 101 102 /* 103 * Make sure that there are no leases. get_write_access() protects 104 * against the truncate racing with a lease-granting setlease(). 105 */ 106 error = break_lease(inode, O_WRONLY); 107 if (error) 108 goto put_write_and_out; 109 110 error = security_path_truncate(path); 111 if (!error) 112 error = do_truncate(idmap, path->dentry, length, 0, NULL); 113 114 put_write_and_out: 115 put_write_access(inode); 116 mnt_drop_write_and_out: 117 mnt_drop_write(path->mnt); 118 out: 119 return error; 120 } 121 EXPORT_SYMBOL_GPL(vfs_truncate); 122 123 long do_sys_truncate(const char __user *pathname, loff_t length) 124 { 125 unsigned int lookup_flags = LOOKUP_FOLLOW; 126 struct path path; 127 int error; 128 129 if (length < 0) /* sorry, but loff_t says... */ 130 return -EINVAL; 131 132 retry: 133 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); 134 if (!error) { 135 error = vfs_truncate(&path, length); 136 path_put(&path); 137 } 138 if (retry_estale(error, lookup_flags)) { 139 lookup_flags |= LOOKUP_REVAL; 140 goto retry; 141 } 142 return error; 143 } 144 145 SYSCALL_DEFINE2(truncate, const char __user *, path, long, length) 146 { 147 return do_sys_truncate(path, length); 148 } 149 150 #ifdef CONFIG_COMPAT 151 COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length) 152 { 153 return do_sys_truncate(path, length); 154 } 155 #endif 156 157 long do_sys_ftruncate(unsigned int fd, loff_t length, int small) 158 { 159 struct inode *inode; 160 struct dentry *dentry; 161 struct fd f; 162 int error; 163 164 error = -EINVAL; 165 if (length < 0) 166 goto out; 167 error = -EBADF; 168 f = fdget(fd); 169 if (!f.file) 170 goto out; 171 172 /* explicitly opened as large or we are on 64-bit box */ 173 if (f.file->f_flags & O_LARGEFILE) 174 small = 0; 175 176 dentry = f.file->f_path.dentry; 177 inode = dentry->d_inode; 178 error = -EINVAL; 179 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) 180 goto out_putf; 181 182 error = -EINVAL; 183 /* Cannot ftruncate over 2^31 bytes without large file support */ 184 if (small && length > MAX_NON_LFS) 185 goto out_putf; 186 187 error = -EPERM; 188 /* Check IS_APPEND on real upper inode */ 189 if (IS_APPEND(file_inode(f.file))) 190 goto out_putf; 191 sb_start_write(inode->i_sb); 192 error = security_file_truncate(f.file); 193 if (!error) 194 error = do_truncate(file_mnt_idmap(f.file), dentry, length, 195 ATTR_MTIME | ATTR_CTIME, f.file); 196 sb_end_write(inode->i_sb); 197 out_putf: 198 fdput(f); 199 out: 200 return error; 201 } 202 203 SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) 204 { 205 return do_sys_ftruncate(fd, length, 1); 206 } 207 208 #ifdef CONFIG_COMPAT 209 COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length) 210 { 211 return do_sys_ftruncate(fd, length, 1); 212 } 213 #endif 214 215 /* LFS versions of truncate are only needed on 32 bit machines */ 216 #if BITS_PER_LONG == 32 217 SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length) 218 { 219 return do_sys_truncate(path, length); 220 } 221 222 SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length) 223 { 224 return do_sys_ftruncate(fd, length, 0); 225 } 226 #endif /* BITS_PER_LONG == 32 */ 227 228 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64) 229 COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname, 230 compat_arg_u64_dual(length)) 231 { 232 return ksys_truncate(pathname, compat_arg_u64_glue(length)); 233 } 234 #endif 235 236 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64) 237 COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd, 238 compat_arg_u64_dual(length)) 239 { 240 return ksys_ftruncate(fd, compat_arg_u64_glue(length)); 241 } 242 #endif 243 244 int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 245 { 246 struct inode *inode = file_inode(file); 247 long ret; 248 249 if (offset < 0 || len <= 0) 250 return -EINVAL; 251 252 /* Return error if mode is not supported */ 253 if (mode & ~FALLOC_FL_SUPPORTED_MASK) 254 return -EOPNOTSUPP; 255 256 /* Punch hole and zero range are mutually exclusive */ 257 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) == 258 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) 259 return -EOPNOTSUPP; 260 261 /* Punch hole must have keep size set */ 262 if ((mode & FALLOC_FL_PUNCH_HOLE) && 263 !(mode & FALLOC_FL_KEEP_SIZE)) 264 return -EOPNOTSUPP; 265 266 /* Collapse range should only be used exclusively. */ 267 if ((mode & FALLOC_FL_COLLAPSE_RANGE) && 268 (mode & ~FALLOC_FL_COLLAPSE_RANGE)) 269 return -EINVAL; 270 271 /* Insert range should only be used exclusively. */ 272 if ((mode & FALLOC_FL_INSERT_RANGE) && 273 (mode & ~FALLOC_FL_INSERT_RANGE)) 274 return -EINVAL; 275 276 /* Unshare range should only be used with allocate mode. */ 277 if ((mode & FALLOC_FL_UNSHARE_RANGE) && 278 (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE))) 279 return -EINVAL; 280 281 if (!(file->f_mode & FMODE_WRITE)) 282 return -EBADF; 283 284 /* 285 * We can only allow pure fallocate on append only files 286 */ 287 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode)) 288 return -EPERM; 289 290 if (IS_IMMUTABLE(inode)) 291 return -EPERM; 292 293 /* 294 * We cannot allow any fallocate operation on an active swapfile 295 */ 296 if (IS_SWAPFILE(inode)) 297 return -ETXTBSY; 298 299 /* 300 * Revalidate the write permissions, in case security policy has 301 * changed since the files were opened. 302 */ 303 ret = security_file_permission(file, MAY_WRITE); 304 if (ret) 305 return ret; 306 307 if (S_ISFIFO(inode->i_mode)) 308 return -ESPIPE; 309 310 if (S_ISDIR(inode->i_mode)) 311 return -EISDIR; 312 313 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) 314 return -ENODEV; 315 316 /* Check for wrap through zero too */ 317 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) 318 return -EFBIG; 319 320 if (!file->f_op->fallocate) 321 return -EOPNOTSUPP; 322 323 file_start_write(file); 324 ret = file->f_op->fallocate(file, mode, offset, len); 325 326 /* 327 * Create inotify and fanotify events. 328 * 329 * To keep the logic simple always create events if fallocate succeeds. 330 * This implies that events are even created if the file size remains 331 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE. 332 */ 333 if (ret == 0) 334 fsnotify_modify(file); 335 336 file_end_write(file); 337 return ret; 338 } 339 EXPORT_SYMBOL_GPL(vfs_fallocate); 340 341 int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len) 342 { 343 struct fd f = fdget(fd); 344 int error = -EBADF; 345 346 if (f.file) { 347 error = vfs_fallocate(f.file, mode, offset, len); 348 fdput(f); 349 } 350 return error; 351 } 352 353 SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len) 354 { 355 return ksys_fallocate(fd, mode, offset, len); 356 } 357 358 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE) 359 COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode, compat_arg_u64_dual(offset), 360 compat_arg_u64_dual(len)) 361 { 362 return ksys_fallocate(fd, mode, compat_arg_u64_glue(offset), 363 compat_arg_u64_glue(len)); 364 } 365 #endif 366 367 /* 368 * access() needs to use the real uid/gid, not the effective uid/gid. 369 * We do this by temporarily clearing all FS-related capabilities and 370 * switching the fsuid/fsgid around to the real ones. 371 */ 372 static const struct cred *access_override_creds(void) 373 { 374 const struct cred *old_cred; 375 struct cred *override_cred; 376 377 override_cred = prepare_creds(); 378 if (!override_cred) 379 return NULL; 380 381 override_cred->fsuid = override_cred->uid; 382 override_cred->fsgid = override_cred->gid; 383 384 if (!issecure(SECURE_NO_SETUID_FIXUP)) { 385 /* Clear the capabilities if we switch to a non-root user */ 386 kuid_t root_uid = make_kuid(override_cred->user_ns, 0); 387 if (!uid_eq(override_cred->uid, root_uid)) 388 cap_clear(override_cred->cap_effective); 389 else 390 override_cred->cap_effective = 391 override_cred->cap_permitted; 392 } 393 394 /* 395 * The new set of credentials can *only* be used in 396 * task-synchronous circumstances, and does not need 397 * RCU freeing, unless somebody then takes a separate 398 * reference to it. 399 * 400 * NOTE! This is _only_ true because this credential 401 * is used purely for override_creds() that installs 402 * it as the subjective cred. Other threads will be 403 * accessing ->real_cred, not the subjective cred. 404 * 405 * If somebody _does_ make a copy of this (using the 406 * 'get_current_cred()' function), that will clear the 407 * non_rcu field, because now that other user may be 408 * expecting RCU freeing. But normal thread-synchronous 409 * cred accesses will keep things non-RCY. 410 */ 411 override_cred->non_rcu = 1; 412 413 old_cred = override_creds(override_cred); 414 415 /* override_cred() gets its own ref */ 416 put_cred(override_cred); 417 418 return old_cred; 419 } 420 421 static long do_faccessat(int dfd, const char __user *filename, int mode, int flags) 422 { 423 struct path path; 424 struct inode *inode; 425 int res; 426 unsigned int lookup_flags = LOOKUP_FOLLOW; 427 const struct cred *old_cred = NULL; 428 429 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ 430 return -EINVAL; 431 432 if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) 433 return -EINVAL; 434 435 if (flags & AT_SYMLINK_NOFOLLOW) 436 lookup_flags &= ~LOOKUP_FOLLOW; 437 if (flags & AT_EMPTY_PATH) 438 lookup_flags |= LOOKUP_EMPTY; 439 440 if (!(flags & AT_EACCESS)) { 441 old_cred = access_override_creds(); 442 if (!old_cred) 443 return -ENOMEM; 444 } 445 446 retry: 447 res = user_path_at(dfd, filename, lookup_flags, &path); 448 if (res) 449 goto out; 450 451 inode = d_backing_inode(path.dentry); 452 453 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) { 454 /* 455 * MAY_EXEC on regular files is denied if the fs is mounted 456 * with the "noexec" flag. 457 */ 458 res = -EACCES; 459 if (path_noexec(&path)) 460 goto out_path_release; 461 } 462 463 res = inode_permission(mnt_idmap(path.mnt), inode, mode | MAY_ACCESS); 464 /* SuS v2 requires we report a read only fs too */ 465 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode)) 466 goto out_path_release; 467 /* 468 * This is a rare case where using __mnt_is_readonly() 469 * is OK without a mnt_want/drop_write() pair. Since 470 * no actual write to the fs is performed here, we do 471 * not need to telegraph to that to anyone. 472 * 473 * By doing this, we accept that this access is 474 * inherently racy and know that the fs may change 475 * state before we even see this result. 476 */ 477 if (__mnt_is_readonly(path.mnt)) 478 res = -EROFS; 479 480 out_path_release: 481 path_put(&path); 482 if (retry_estale(res, lookup_flags)) { 483 lookup_flags |= LOOKUP_REVAL; 484 goto retry; 485 } 486 out: 487 if (old_cred) 488 revert_creds(old_cred); 489 490 return res; 491 } 492 493 SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) 494 { 495 return do_faccessat(dfd, filename, mode, 0); 496 } 497 498 SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode, 499 int, flags) 500 { 501 return do_faccessat(dfd, filename, mode, flags); 502 } 503 504 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) 505 { 506 return do_faccessat(AT_FDCWD, filename, mode, 0); 507 } 508 509 SYSCALL_DEFINE1(chdir, const char __user *, filename) 510 { 511 struct path path; 512 int error; 513 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 514 retry: 515 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); 516 if (error) 517 goto out; 518 519 error = path_permission(&path, MAY_EXEC | MAY_CHDIR); 520 if (error) 521 goto dput_and_out; 522 523 set_fs_pwd(current->fs, &path); 524 525 dput_and_out: 526 path_put(&path); 527 if (retry_estale(error, lookup_flags)) { 528 lookup_flags |= LOOKUP_REVAL; 529 goto retry; 530 } 531 out: 532 return error; 533 } 534 535 SYSCALL_DEFINE1(fchdir, unsigned int, fd) 536 { 537 struct fd f = fdget_raw(fd); 538 int error; 539 540 error = -EBADF; 541 if (!f.file) 542 goto out; 543 544 error = -ENOTDIR; 545 if (!d_can_lookup(f.file->f_path.dentry)) 546 goto out_putf; 547 548 error = file_permission(f.file, MAY_EXEC | MAY_CHDIR); 549 if (!error) 550 set_fs_pwd(current->fs, &f.file->f_path); 551 out_putf: 552 fdput(f); 553 out: 554 return error; 555 } 556 557 SYSCALL_DEFINE1(chroot, const char __user *, filename) 558 { 559 struct path path; 560 int error; 561 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 562 retry: 563 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); 564 if (error) 565 goto out; 566 567 error = path_permission(&path, MAY_EXEC | MAY_CHDIR); 568 if (error) 569 goto dput_and_out; 570 571 error = -EPERM; 572 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT)) 573 goto dput_and_out; 574 error = security_path_chroot(&path); 575 if (error) 576 goto dput_and_out; 577 578 set_fs_root(current->fs, &path); 579 error = 0; 580 dput_and_out: 581 path_put(&path); 582 if (retry_estale(error, lookup_flags)) { 583 lookup_flags |= LOOKUP_REVAL; 584 goto retry; 585 } 586 out: 587 return error; 588 } 589 590 int chmod_common(const struct path *path, umode_t mode) 591 { 592 struct inode *inode = path->dentry->d_inode; 593 struct inode *delegated_inode = NULL; 594 struct iattr newattrs; 595 int error; 596 597 error = mnt_want_write(path->mnt); 598 if (error) 599 return error; 600 retry_deleg: 601 inode_lock(inode); 602 error = security_path_chmod(path, mode); 603 if (error) 604 goto out_unlock; 605 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); 606 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; 607 error = notify_change(mnt_idmap(path->mnt), path->dentry, 608 &newattrs, &delegated_inode); 609 out_unlock: 610 inode_unlock(inode); 611 if (delegated_inode) { 612 error = break_deleg_wait(&delegated_inode); 613 if (!error) 614 goto retry_deleg; 615 } 616 mnt_drop_write(path->mnt); 617 return error; 618 } 619 620 int vfs_fchmod(struct file *file, umode_t mode) 621 { 622 audit_file(file); 623 return chmod_common(&file->f_path, mode); 624 } 625 626 SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) 627 { 628 struct fd f = fdget(fd); 629 int err = -EBADF; 630 631 if (f.file) { 632 err = vfs_fchmod(f.file, mode); 633 fdput(f); 634 } 635 return err; 636 } 637 638 static int do_fchmodat(int dfd, const char __user *filename, umode_t mode) 639 { 640 struct path path; 641 int error; 642 unsigned int lookup_flags = LOOKUP_FOLLOW; 643 retry: 644 error = user_path_at(dfd, filename, lookup_flags, &path); 645 if (!error) { 646 error = chmod_common(&path, mode); 647 path_put(&path); 648 if (retry_estale(error, lookup_flags)) { 649 lookup_flags |= LOOKUP_REVAL; 650 goto retry; 651 } 652 } 653 return error; 654 } 655 656 SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, 657 umode_t, mode) 658 { 659 return do_fchmodat(dfd, filename, mode); 660 } 661 662 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) 663 { 664 return do_fchmodat(AT_FDCWD, filename, mode); 665 } 666 667 /** 668 * setattr_vfsuid - check and set ia_fsuid attribute 669 * @kuid: new inode owner 670 * 671 * Check whether @kuid is valid and if so generate and set vfsuid_t in 672 * ia_vfsuid. 673 * 674 * Return: true if @kuid is valid, false if not. 675 */ 676 static inline bool setattr_vfsuid(struct iattr *attr, kuid_t kuid) 677 { 678 if (!uid_valid(kuid)) 679 return false; 680 attr->ia_valid |= ATTR_UID; 681 attr->ia_vfsuid = VFSUIDT_INIT(kuid); 682 return true; 683 } 684 685 /** 686 * setattr_vfsgid - check and set ia_fsgid attribute 687 * @kgid: new inode owner 688 * 689 * Check whether @kgid is valid and if so generate and set vfsgid_t in 690 * ia_vfsgid. 691 * 692 * Return: true if @kgid is valid, false if not. 693 */ 694 static inline bool setattr_vfsgid(struct iattr *attr, kgid_t kgid) 695 { 696 if (!gid_valid(kgid)) 697 return false; 698 attr->ia_valid |= ATTR_GID; 699 attr->ia_vfsgid = VFSGIDT_INIT(kgid); 700 return true; 701 } 702 703 int chown_common(const struct path *path, uid_t user, gid_t group) 704 { 705 struct mnt_idmap *idmap; 706 struct user_namespace *fs_userns; 707 struct inode *inode = path->dentry->d_inode; 708 struct inode *delegated_inode = NULL; 709 int error; 710 struct iattr newattrs; 711 kuid_t uid; 712 kgid_t gid; 713 714 uid = make_kuid(current_user_ns(), user); 715 gid = make_kgid(current_user_ns(), group); 716 717 idmap = mnt_idmap(path->mnt); 718 fs_userns = i_user_ns(inode); 719 720 retry_deleg: 721 newattrs.ia_vfsuid = INVALID_VFSUID; 722 newattrs.ia_vfsgid = INVALID_VFSGID; 723 newattrs.ia_valid = ATTR_CTIME; 724 if ((user != (uid_t)-1) && !setattr_vfsuid(&newattrs, uid)) 725 return -EINVAL; 726 if ((group != (gid_t)-1) && !setattr_vfsgid(&newattrs, gid)) 727 return -EINVAL; 728 inode_lock(inode); 729 if (!S_ISDIR(inode->i_mode)) 730 newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV | 731 setattr_should_drop_sgid(idmap, inode); 732 /* Continue to send actual fs values, not the mount values. */ 733 error = security_path_chown( 734 path, 735 from_vfsuid(idmap, fs_userns, newattrs.ia_vfsuid), 736 from_vfsgid(idmap, fs_userns, newattrs.ia_vfsgid)); 737 if (!error) 738 error = notify_change(idmap, path->dentry, &newattrs, 739 &delegated_inode); 740 inode_unlock(inode); 741 if (delegated_inode) { 742 error = break_deleg_wait(&delegated_inode); 743 if (!error) 744 goto retry_deleg; 745 } 746 return error; 747 } 748 749 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, 750 int flag) 751 { 752 struct path path; 753 int error = -EINVAL; 754 int lookup_flags; 755 756 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) 757 goto out; 758 759 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; 760 if (flag & AT_EMPTY_PATH) 761 lookup_flags |= LOOKUP_EMPTY; 762 retry: 763 error = user_path_at(dfd, filename, lookup_flags, &path); 764 if (error) 765 goto out; 766 error = mnt_want_write(path.mnt); 767 if (error) 768 goto out_release; 769 error = chown_common(&path, user, group); 770 mnt_drop_write(path.mnt); 771 out_release: 772 path_put(&path); 773 if (retry_estale(error, lookup_flags)) { 774 lookup_flags |= LOOKUP_REVAL; 775 goto retry; 776 } 777 out: 778 return error; 779 } 780 781 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, 782 gid_t, group, int, flag) 783 { 784 return do_fchownat(dfd, filename, user, group, flag); 785 } 786 787 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group) 788 { 789 return do_fchownat(AT_FDCWD, filename, user, group, 0); 790 } 791 792 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group) 793 { 794 return do_fchownat(AT_FDCWD, filename, user, group, 795 AT_SYMLINK_NOFOLLOW); 796 } 797 798 int vfs_fchown(struct file *file, uid_t user, gid_t group) 799 { 800 int error; 801 802 error = mnt_want_write_file(file); 803 if (error) 804 return error; 805 audit_file(file); 806 error = chown_common(&file->f_path, user, group); 807 mnt_drop_write_file(file); 808 return error; 809 } 810 811 int ksys_fchown(unsigned int fd, uid_t user, gid_t group) 812 { 813 struct fd f = fdget(fd); 814 int error = -EBADF; 815 816 if (f.file) { 817 error = vfs_fchown(f.file, user, group); 818 fdput(f); 819 } 820 return error; 821 } 822 823 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) 824 { 825 return ksys_fchown(fd, user, group); 826 } 827 828 static int do_dentry_open(struct file *f, 829 struct inode *inode, 830 int (*open)(struct inode *, struct file *)) 831 { 832 static const struct file_operations empty_fops = {}; 833 int error; 834 835 path_get(&f->f_path); 836 f->f_inode = inode; 837 f->f_mapping = inode->i_mapping; 838 f->f_wb_err = filemap_sample_wb_err(f->f_mapping); 839 f->f_sb_err = file_sample_sb_err(f); 840 841 if (unlikely(f->f_flags & O_PATH)) { 842 f->f_mode = FMODE_PATH | FMODE_OPENED; 843 f->f_op = &empty_fops; 844 return 0; 845 } 846 847 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) { 848 i_readcount_inc(inode); 849 } else if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { 850 error = get_write_access(inode); 851 if (unlikely(error)) 852 goto cleanup_file; 853 error = __mnt_want_write(f->f_path.mnt); 854 if (unlikely(error)) { 855 put_write_access(inode); 856 goto cleanup_file; 857 } 858 f->f_mode |= FMODE_WRITER; 859 } 860 861 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */ 862 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)) 863 f->f_mode |= FMODE_ATOMIC_POS; 864 865 f->f_op = fops_get(inode->i_fop); 866 if (WARN_ON(!f->f_op)) { 867 error = -ENODEV; 868 goto cleanup_all; 869 } 870 871 error = security_file_open(f); 872 if (error) 873 goto cleanup_all; 874 875 error = break_lease(file_inode(f), f->f_flags); 876 if (error) 877 goto cleanup_all; 878 879 /* normally all 3 are set; ->open() can clear them if needed */ 880 f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; 881 if (!open) 882 open = f->f_op->open; 883 if (open) { 884 error = open(inode, f); 885 if (error) 886 goto cleanup_all; 887 } 888 f->f_mode |= FMODE_OPENED; 889 if ((f->f_mode & FMODE_READ) && 890 likely(f->f_op->read || f->f_op->read_iter)) 891 f->f_mode |= FMODE_CAN_READ; 892 if ((f->f_mode & FMODE_WRITE) && 893 likely(f->f_op->write || f->f_op->write_iter)) 894 f->f_mode |= FMODE_CAN_WRITE; 895 if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek) 896 f->f_mode &= ~FMODE_LSEEK; 897 if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO) 898 f->f_mode |= FMODE_CAN_ODIRECT; 899 900 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); 901 f->f_iocb_flags = iocb_flags(f); 902 903 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); 904 905 if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT)) 906 return -EINVAL; 907 908 /* 909 * XXX: Huge page cache doesn't support writing yet. Drop all page 910 * cache for this file before processing writes. 911 */ 912 if (f->f_mode & FMODE_WRITE) { 913 /* 914 * Paired with smp_mb() in collapse_file() to ensure nr_thps 915 * is up to date and the update to i_writecount by 916 * get_write_access() is visible. Ensures subsequent insertion 917 * of THPs into the page cache will fail. 918 */ 919 smp_mb(); 920 if (filemap_nr_thps(inode->i_mapping)) { 921 struct address_space *mapping = inode->i_mapping; 922 923 filemap_invalidate_lock(inode->i_mapping); 924 /* 925 * unmap_mapping_range just need to be called once 926 * here, because the private pages is not need to be 927 * unmapped mapping (e.g. data segment of dynamic 928 * shared libraries here). 929 */ 930 unmap_mapping_range(mapping, 0, 0, 0); 931 truncate_inode_pages(mapping, 0); 932 filemap_invalidate_unlock(inode->i_mapping); 933 } 934 } 935 936 return 0; 937 938 cleanup_all: 939 if (WARN_ON_ONCE(error > 0)) 940 error = -EINVAL; 941 fops_put(f->f_op); 942 put_file_access(f); 943 cleanup_file: 944 path_put(&f->f_path); 945 f->f_path.mnt = NULL; 946 f->f_path.dentry = NULL; 947 f->f_inode = NULL; 948 return error; 949 } 950 951 /** 952 * finish_open - finish opening a file 953 * @file: file pointer 954 * @dentry: pointer to dentry 955 * @open: open callback 956 * @opened: state of open 957 * 958 * This can be used to finish opening a file passed to i_op->atomic_open(). 959 * 960 * If the open callback is set to NULL, then the standard f_op->open() 961 * filesystem callback is substituted. 962 * 963 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is 964 * the return value of d_splice_alias(), then the caller needs to perform dput() 965 * on it after finish_open(). 966 * 967 * Returns zero on success or -errno if the open failed. 968 */ 969 int finish_open(struct file *file, struct dentry *dentry, 970 int (*open)(struct inode *, struct file *)) 971 { 972 BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */ 973 974 file->f_path.dentry = dentry; 975 return do_dentry_open(file, d_backing_inode(dentry), open); 976 } 977 EXPORT_SYMBOL(finish_open); 978 979 /** 980 * finish_no_open - finish ->atomic_open() without opening the file 981 * 982 * @file: file pointer 983 * @dentry: dentry or NULL (as returned from ->lookup()) 984 * 985 * This can be used to set the result of a successful lookup in ->atomic_open(). 986 * 987 * NB: unlike finish_open() this function does consume the dentry reference and 988 * the caller need not dput() it. 989 * 990 * Returns "0" which must be the return value of ->atomic_open() after having 991 * called this function. 992 */ 993 int finish_no_open(struct file *file, struct dentry *dentry) 994 { 995 file->f_path.dentry = dentry; 996 return 0; 997 } 998 EXPORT_SYMBOL(finish_no_open); 999 1000 char *file_path(struct file *filp, char *buf, int buflen) 1001 { 1002 return d_path(&filp->f_path, buf, buflen); 1003 } 1004 EXPORT_SYMBOL(file_path); 1005 1006 /** 1007 * vfs_open - open the file at the given path 1008 * @path: path to open 1009 * @file: newly allocated file with f_flag initialized 1010 * @cred: credentials to use 1011 */ 1012 int vfs_open(const struct path *path, struct file *file) 1013 { 1014 file->f_path = *path; 1015 return do_dentry_open(file, d_backing_inode(path->dentry), NULL); 1016 } 1017 1018 struct file *dentry_open(const struct path *path, int flags, 1019 const struct cred *cred) 1020 { 1021 int error; 1022 struct file *f; 1023 1024 validate_creds(cred); 1025 1026 /* We must always pass in a valid mount pointer. */ 1027 BUG_ON(!path->mnt); 1028 1029 f = alloc_empty_file(flags, cred); 1030 if (!IS_ERR(f)) { 1031 error = vfs_open(path, f); 1032 if (error) { 1033 fput(f); 1034 f = ERR_PTR(error); 1035 } 1036 } 1037 return f; 1038 } 1039 EXPORT_SYMBOL(dentry_open); 1040 1041 /** 1042 * dentry_create - Create and open a file 1043 * @path: path to create 1044 * @flags: O_ flags 1045 * @mode: mode bits for new file 1046 * @cred: credentials to use 1047 * 1048 * Caller must hold the parent directory's lock, and have prepared 1049 * a negative dentry, placed in @path->dentry, for the new file. 1050 * 1051 * Caller sets @path->mnt to the vfsmount of the filesystem where 1052 * the new file is to be created. The parent directory and the 1053 * negative dentry must reside on the same filesystem instance. 1054 * 1055 * On success, returns a "struct file *". Otherwise a ERR_PTR 1056 * is returned. 1057 */ 1058 struct file *dentry_create(const struct path *path, int flags, umode_t mode, 1059 const struct cred *cred) 1060 { 1061 struct file *f; 1062 int error; 1063 1064 validate_creds(cred); 1065 f = alloc_empty_file(flags, cred); 1066 if (IS_ERR(f)) 1067 return f; 1068 1069 error = vfs_create(mnt_idmap(path->mnt), 1070 d_inode(path->dentry->d_parent), 1071 path->dentry, mode, true); 1072 if (!error) 1073 error = vfs_open(path, f); 1074 1075 if (unlikely(error)) { 1076 fput(f); 1077 return ERR_PTR(error); 1078 } 1079 return f; 1080 } 1081 EXPORT_SYMBOL(dentry_create); 1082 1083 struct file *open_with_fake_path(const struct path *path, int flags, 1084 struct inode *inode, const struct cred *cred) 1085 { 1086 struct file *f = alloc_empty_file_noaccount(flags, cred); 1087 if (!IS_ERR(f)) { 1088 int error; 1089 1090 f->f_path = *path; 1091 error = do_dentry_open(f, inode, NULL); 1092 if (error) { 1093 fput(f); 1094 f = ERR_PTR(error); 1095 } 1096 } 1097 return f; 1098 } 1099 EXPORT_SYMBOL(open_with_fake_path); 1100 1101 #define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE)) 1102 #define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC) 1103 1104 inline struct open_how build_open_how(int flags, umode_t mode) 1105 { 1106 struct open_how how = { 1107 .flags = flags & VALID_OPEN_FLAGS, 1108 .mode = mode & S_IALLUGO, 1109 }; 1110 1111 /* O_PATH beats everything else. */ 1112 if (how.flags & O_PATH) 1113 how.flags &= O_PATH_FLAGS; 1114 /* Modes should only be set for create-like flags. */ 1115 if (!WILL_CREATE(how.flags)) 1116 how.mode = 0; 1117 return how; 1118 } 1119 1120 inline int build_open_flags(const struct open_how *how, struct open_flags *op) 1121 { 1122 u64 flags = how->flags; 1123 u64 strip = FMODE_NONOTIFY | O_CLOEXEC; 1124 int lookup_flags = 0; 1125 int acc_mode = ACC_MODE(flags); 1126 1127 BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS), 1128 "struct open_flags doesn't yet handle flags > 32 bits"); 1129 1130 /* 1131 * Strip flags that either shouldn't be set by userspace like 1132 * FMODE_NONOTIFY or that aren't relevant in determining struct 1133 * open_flags like O_CLOEXEC. 1134 */ 1135 flags &= ~strip; 1136 1137 /* 1138 * Older syscalls implicitly clear all of the invalid flags or argument 1139 * values before calling build_open_flags(), but openat2(2) checks all 1140 * of its arguments. 1141 */ 1142 if (flags & ~VALID_OPEN_FLAGS) 1143 return -EINVAL; 1144 if (how->resolve & ~VALID_RESOLVE_FLAGS) 1145 return -EINVAL; 1146 1147 /* Scoping flags are mutually exclusive. */ 1148 if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT)) 1149 return -EINVAL; 1150 1151 /* Deal with the mode. */ 1152 if (WILL_CREATE(flags)) { 1153 if (how->mode & ~S_IALLUGO) 1154 return -EINVAL; 1155 op->mode = how->mode | S_IFREG; 1156 } else { 1157 if (how->mode != 0) 1158 return -EINVAL; 1159 op->mode = 0; 1160 } 1161 1162 /* 1163 * In order to ensure programs get explicit errors when trying to use 1164 * O_TMPFILE on old kernels, O_TMPFILE is implemented such that it 1165 * looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we 1166 * have to require userspace to explicitly set it. 1167 */ 1168 if (flags & __O_TMPFILE) { 1169 if ((flags & O_TMPFILE_MASK) != O_TMPFILE) 1170 return -EINVAL; 1171 if (!(acc_mode & MAY_WRITE)) 1172 return -EINVAL; 1173 } 1174 if (flags & O_PATH) { 1175 /* O_PATH only permits certain other flags to be set. */ 1176 if (flags & ~O_PATH_FLAGS) 1177 return -EINVAL; 1178 acc_mode = 0; 1179 } 1180 1181 /* 1182 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only 1183 * check for O_DSYNC if the need any syncing at all we enforce it's 1184 * always set instead of having to deal with possibly weird behaviour 1185 * for malicious applications setting only __O_SYNC. 1186 */ 1187 if (flags & __O_SYNC) 1188 flags |= O_DSYNC; 1189 1190 op->open_flag = flags; 1191 1192 /* O_TRUNC implies we need access checks for write permissions */ 1193 if (flags & O_TRUNC) 1194 acc_mode |= MAY_WRITE; 1195 1196 /* Allow the LSM permission hook to distinguish append 1197 access from general write access. */ 1198 if (flags & O_APPEND) 1199 acc_mode |= MAY_APPEND; 1200 1201 op->acc_mode = acc_mode; 1202 1203 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN; 1204 1205 if (flags & O_CREAT) { 1206 op->intent |= LOOKUP_CREATE; 1207 if (flags & O_EXCL) { 1208 op->intent |= LOOKUP_EXCL; 1209 flags |= O_NOFOLLOW; 1210 } 1211 } 1212 1213 if (flags & O_DIRECTORY) 1214 lookup_flags |= LOOKUP_DIRECTORY; 1215 if (!(flags & O_NOFOLLOW)) 1216 lookup_flags |= LOOKUP_FOLLOW; 1217 1218 if (how->resolve & RESOLVE_NO_XDEV) 1219 lookup_flags |= LOOKUP_NO_XDEV; 1220 if (how->resolve & RESOLVE_NO_MAGICLINKS) 1221 lookup_flags |= LOOKUP_NO_MAGICLINKS; 1222 if (how->resolve & RESOLVE_NO_SYMLINKS) 1223 lookup_flags |= LOOKUP_NO_SYMLINKS; 1224 if (how->resolve & RESOLVE_BENEATH) 1225 lookup_flags |= LOOKUP_BENEATH; 1226 if (how->resolve & RESOLVE_IN_ROOT) 1227 lookup_flags |= LOOKUP_IN_ROOT; 1228 if (how->resolve & RESOLVE_CACHED) { 1229 /* Don't bother even trying for create/truncate/tmpfile open */ 1230 if (flags & (O_TRUNC | O_CREAT | O_TMPFILE)) 1231 return -EAGAIN; 1232 lookup_flags |= LOOKUP_CACHED; 1233 } 1234 1235 op->lookup_flags = lookup_flags; 1236 return 0; 1237 } 1238 1239 /** 1240 * file_open_name - open file and return file pointer 1241 * 1242 * @name: struct filename containing path to open 1243 * @flags: open flags as per the open(2) second argument 1244 * @mode: mode for the new file if O_CREAT is set, else ignored 1245 * 1246 * This is the helper to open a file from kernelspace if you really 1247 * have to. But in generally you should not do this, so please move 1248 * along, nothing to see here.. 1249 */ 1250 struct file *file_open_name(struct filename *name, int flags, umode_t mode) 1251 { 1252 struct open_flags op; 1253 struct open_how how = build_open_how(flags, mode); 1254 int err = build_open_flags(&how, &op); 1255 if (err) 1256 return ERR_PTR(err); 1257 return do_filp_open(AT_FDCWD, name, &op); 1258 } 1259 1260 /** 1261 * filp_open - open file and return file pointer 1262 * 1263 * @filename: path to open 1264 * @flags: open flags as per the open(2) second argument 1265 * @mode: mode for the new file if O_CREAT is set, else ignored 1266 * 1267 * This is the helper to open a file from kernelspace if you really 1268 * have to. But in generally you should not do this, so please move 1269 * along, nothing to see here.. 1270 */ 1271 struct file *filp_open(const char *filename, int flags, umode_t mode) 1272 { 1273 struct filename *name = getname_kernel(filename); 1274 struct file *file = ERR_CAST(name); 1275 1276 if (!IS_ERR(name)) { 1277 file = file_open_name(name, flags, mode); 1278 putname(name); 1279 } 1280 return file; 1281 } 1282 EXPORT_SYMBOL(filp_open); 1283 1284 struct file *file_open_root(const struct path *root, 1285 const char *filename, int flags, umode_t mode) 1286 { 1287 struct open_flags op; 1288 struct open_how how = build_open_how(flags, mode); 1289 int err = build_open_flags(&how, &op); 1290 if (err) 1291 return ERR_PTR(err); 1292 return do_file_open_root(root, filename, &op); 1293 } 1294 EXPORT_SYMBOL(file_open_root); 1295 1296 static long do_sys_openat2(int dfd, const char __user *filename, 1297 struct open_how *how) 1298 { 1299 struct open_flags op; 1300 int fd = build_open_flags(how, &op); 1301 struct filename *tmp; 1302 1303 if (fd) 1304 return fd; 1305 1306 tmp = getname(filename); 1307 if (IS_ERR(tmp)) 1308 return PTR_ERR(tmp); 1309 1310 fd = get_unused_fd_flags(how->flags); 1311 if (fd >= 0) { 1312 struct file *f = do_filp_open(dfd, tmp, &op); 1313 if (IS_ERR(f)) { 1314 put_unused_fd(fd); 1315 fd = PTR_ERR(f); 1316 } else { 1317 fsnotify_open(f); 1318 fd_install(fd, f); 1319 } 1320 } 1321 putname(tmp); 1322 return fd; 1323 } 1324 1325 long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode) 1326 { 1327 struct open_how how = build_open_how(flags, mode); 1328 return do_sys_openat2(dfd, filename, &how); 1329 } 1330 1331 1332 SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) 1333 { 1334 if (force_o_largefile()) 1335 flags |= O_LARGEFILE; 1336 return do_sys_open(AT_FDCWD, filename, flags, mode); 1337 } 1338 1339 SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, 1340 umode_t, mode) 1341 { 1342 if (force_o_largefile()) 1343 flags |= O_LARGEFILE; 1344 return do_sys_open(dfd, filename, flags, mode); 1345 } 1346 1347 SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename, 1348 struct open_how __user *, how, size_t, usize) 1349 { 1350 int err; 1351 struct open_how tmp; 1352 1353 BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0); 1354 BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST); 1355 1356 if (unlikely(usize < OPEN_HOW_SIZE_VER0)) 1357 return -EINVAL; 1358 1359 err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize); 1360 if (err) 1361 return err; 1362 1363 audit_openat2_how(&tmp); 1364 1365 /* O_LARGEFILE is only allowed for non-O_PATH. */ 1366 if (!(tmp.flags & O_PATH) && force_o_largefile()) 1367 tmp.flags |= O_LARGEFILE; 1368 1369 return do_sys_openat2(dfd, filename, &tmp); 1370 } 1371 1372 #ifdef CONFIG_COMPAT 1373 /* 1374 * Exactly like sys_open(), except that it doesn't set the 1375 * O_LARGEFILE flag. 1376 */ 1377 COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) 1378 { 1379 return do_sys_open(AT_FDCWD, filename, flags, mode); 1380 } 1381 1382 /* 1383 * Exactly like sys_openat(), except that it doesn't set the 1384 * O_LARGEFILE flag. 1385 */ 1386 COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode) 1387 { 1388 return do_sys_open(dfd, filename, flags, mode); 1389 } 1390 #endif 1391 1392 #ifndef __alpha__ 1393 1394 /* 1395 * For backward compatibility? Maybe this should be moved 1396 * into arch/i386 instead? 1397 */ 1398 SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode) 1399 { 1400 int flags = O_CREAT | O_WRONLY | O_TRUNC; 1401 1402 if (force_o_largefile()) 1403 flags |= O_LARGEFILE; 1404 return do_sys_open(AT_FDCWD, pathname, flags, mode); 1405 } 1406 #endif 1407 1408 /* 1409 * "id" is the POSIX thread ID. We use the 1410 * files pointer for this.. 1411 */ 1412 int filp_close(struct file *filp, fl_owner_t id) 1413 { 1414 int retval = 0; 1415 1416 if (CHECK_DATA_CORRUPTION(file_count(filp) == 0, 1417 "VFS: Close: file count is 0 (f_op=%ps)", 1418 filp->f_op)) { 1419 return 0; 1420 } 1421 1422 if (filp->f_op->flush) 1423 retval = filp->f_op->flush(filp, id); 1424 1425 if (likely(!(filp->f_mode & FMODE_PATH))) { 1426 dnotify_flush(filp, id); 1427 locks_remove_posix(filp, id); 1428 } 1429 fput(filp); 1430 return retval; 1431 } 1432 1433 EXPORT_SYMBOL(filp_close); 1434 1435 /* 1436 * Careful here! We test whether the file pointer is NULL before 1437 * releasing the fd. This ensures that one clone task can't release 1438 * an fd while another clone is opening it. 1439 */ 1440 SYSCALL_DEFINE1(close, unsigned int, fd) 1441 { 1442 int retval = close_fd(fd); 1443 1444 /* can't restart close syscall because file table entry was cleared */ 1445 if (unlikely(retval == -ERESTARTSYS || 1446 retval == -ERESTARTNOINTR || 1447 retval == -ERESTARTNOHAND || 1448 retval == -ERESTART_RESTARTBLOCK)) 1449 retval = -EINTR; 1450 1451 return retval; 1452 } 1453 1454 /** 1455 * close_range() - Close all file descriptors in a given range. 1456 * 1457 * @fd: starting file descriptor to close 1458 * @max_fd: last file descriptor to close 1459 * @flags: reserved for future extensions 1460 * 1461 * This closes a range of file descriptors. All file descriptors 1462 * from @fd up to and including @max_fd are closed. 1463 * Currently, errors to close a given file descriptor are ignored. 1464 */ 1465 SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd, 1466 unsigned int, flags) 1467 { 1468 return __close_range(fd, max_fd, flags); 1469 } 1470 1471 /* 1472 * This routine simulates a hangup on the tty, to arrange that users 1473 * are given clean terminals at login time. 1474 */ 1475 SYSCALL_DEFINE0(vhangup) 1476 { 1477 if (capable(CAP_SYS_TTY_CONFIG)) { 1478 tty_vhangup_self(); 1479 return 0; 1480 } 1481 return -EPERM; 1482 } 1483 1484 /* 1485 * Called when an inode is about to be open. 1486 * We use this to disallow opening large files on 32bit systems if 1487 * the caller didn't specify O_LARGEFILE. On 64bit systems we force 1488 * on this flag in sys_open. 1489 */ 1490 int generic_file_open(struct inode * inode, struct file * filp) 1491 { 1492 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) 1493 return -EOVERFLOW; 1494 return 0; 1495 } 1496 1497 EXPORT_SYMBOL(generic_file_open); 1498 1499 /* 1500 * This is used by subsystems that don't want seekable 1501 * file descriptors. The function is not supposed to ever fail, the only 1502 * reason it returns an 'int' and not 'void' is so that it can be plugged 1503 * directly into file_operations structure. 1504 */ 1505 int nonseekable_open(struct inode *inode, struct file *filp) 1506 { 1507 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); 1508 return 0; 1509 } 1510 1511 EXPORT_SYMBOL(nonseekable_open); 1512 1513 /* 1514 * stream_open is used by subsystems that want stream-like file descriptors. 1515 * Such file descriptors are not seekable and don't have notion of position 1516 * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL). 1517 * Contrary to file descriptors of other regular files, .read() and .write() 1518 * can run simultaneously. 1519 * 1520 * stream_open never fails and is marked to return int so that it could be 1521 * directly used as file_operations.open . 1522 */ 1523 int stream_open(struct inode *inode, struct file *filp) 1524 { 1525 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS); 1526 filp->f_mode |= FMODE_STREAM; 1527 return 0; 1528 } 1529 1530 EXPORT_SYMBOL(stream_open); 1531