1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * 4 * Copyright (C) 2011 Novell Inc. 5 */ 6 7#include <linux/module.h> 8#include <linux/fs.h> 9#include <linux/slab.h> 10#include <linux/file.h> 11#include <linux/fileattr.h> 12#include <linux/splice.h> 13#include <linux/xattr.h> 14#include <linux/security.h> 15#include <linux/uaccess.h> 16#include <linux/sched/signal.h> 17#include <linux/cred.h> 18#include <linux/namei.h> 19#include <linux/fdtable.h> 20#include <linux/ratelimit.h> 21#include <linux/exportfs.h> 22#include "overlayfs.h" 23 24#define OVL_COPY_UP_CHUNK_SIZE (1 << 20) 25 26static int ovl_ccup_set(const char *buf, const struct kernel_param *param) 27{ 28 pr_warn("\"check_copy_up\" module option is obsolete\n"); 29 return 0; 30} 31 32static int ovl_ccup_get(char *buf, const struct kernel_param *param) 33{ 34 return sprintf(buf, "N\n"); 35} 36 37module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644); 38MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing"); 39 40static bool ovl_must_copy_xattr(const char *name) 41{ 42 return !strcmp(name, XATTR_POSIX_ACL_ACCESS) || 43 !strcmp(name, XATTR_POSIX_ACL_DEFAULT) || 44 !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); 45} 46 47static int ovl_copy_acl(struct ovl_fs *ofs, const struct path *path, 48 struct dentry *dentry, const char *acl_name) 49{ 50 int err; 51 struct posix_acl *clone, *real_acl = NULL; 52 53 real_acl = ovl_get_acl_path(path, acl_name, false); 54 if (!real_acl) 55 return 0; 56 57 if (IS_ERR(real_acl)) { 58 err = PTR_ERR(real_acl); 59 if (err == -ENODATA || err == -EOPNOTSUPP) 60 return 0; 61 return err; 62 } 63 64 clone = posix_acl_clone(real_acl, GFP_KERNEL); 65 posix_acl_release(real_acl); /* release original acl */ 66 if (!clone) 67 return -ENOMEM; 68 69 err = ovl_do_set_acl(ofs, dentry, acl_name, clone); 70 71 /* release cloned acl */ 72 posix_acl_release(clone); 73 return err; 74} 75 76int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new) 77{ 78 struct dentry *old = oldpath->dentry; 79 ssize_t list_size, size, value_size = 0; 80 char *buf, *name, *value = NULL; 81 int error = 0; 82 size_t slen; 83 84 if (!old->d_inode->i_op->listxattr || !new->d_inode->i_op->listxattr) 85 return 0; 86 87 list_size = vfs_listxattr(old, NULL, 0); 88 if (list_size <= 0) { 89 if (list_size == -EOPNOTSUPP) 90 return 0; 91 return list_size; 92 } 93 94 buf = kvzalloc(list_size, GFP_KERNEL); 95 if (!buf) 96 return -ENOMEM; 97 98 list_size = vfs_listxattr(old, buf, list_size); 99 if (list_size <= 0) { 100 error = list_size; 101 goto out; 102 } 103 104 for (name = buf; list_size; name += slen) { 105 slen = strnlen(name, list_size) + 1; 106 107 /* underlying fs providing us with an broken xattr list? */ 108 if (WARN_ON(slen > list_size)) { 109 error = -EIO; 110 break; 111 } 112 list_size -= slen; 113 114 if (ovl_is_private_xattr(sb, name)) 115 continue; 116 117 error = security_inode_copy_up_xattr(name); 118 if (error < 0 && error != -EOPNOTSUPP) 119 break; 120 if (error == 1) { 121 error = 0; 122 continue; /* Discard */ 123 } 124 125 if (is_posix_acl_xattr(name)) { 126 error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name); 127 if (!error) 128 continue; 129 /* POSIX ACLs must be copied. */ 130 break; 131 } 132 133retry: 134 size = ovl_do_getxattr(oldpath, name, value, value_size); 135 if (size == -ERANGE) 136 size = ovl_do_getxattr(oldpath, name, NULL, 0); 137 138 if (size < 0) { 139 error = size; 140 break; 141 } 142 143 if (size > value_size) { 144 void *new; 145 146 new = kvmalloc(size, GFP_KERNEL); 147 if (!new) { 148 error = -ENOMEM; 149 break; 150 } 151 kvfree(value); 152 value = new; 153 value_size = size; 154 goto retry; 155 } 156 157 error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0); 158 if (error) { 159 if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name)) 160 break; 161 162 /* Ignore failure to copy unknown xattrs */ 163 error = 0; 164 } 165 } 166 kvfree(value); 167out: 168 kvfree(buf); 169 return error; 170} 171 172static int ovl_copy_fileattr(struct inode *inode, const struct path *old, 173 const struct path *new) 174{ 175 struct fileattr oldfa = { .flags_valid = true }; 176 struct fileattr newfa = { .flags_valid = true }; 177 int err; 178 179 err = ovl_real_fileattr_get(old, &oldfa); 180 if (err) { 181 /* Ntfs-3g returns -EINVAL for "no fileattr support" */ 182 if (err == -ENOTTY || err == -EINVAL) 183 return 0; 184 pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n", 185 old->dentry, err); 186 return err; 187 } 188 189 /* 190 * We cannot set immutable and append-only flags on upper inode, 191 * because we would not be able to link upper inode to upper dir 192 * not set overlay private xattr on upper inode. 193 * Store these flags in overlay.protattr xattr instead. 194 */ 195 if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) { 196 err = ovl_set_protattr(inode, new->dentry, &oldfa); 197 if (err == -EPERM) 198 pr_warn_once("copying fileattr: no xattr on upper\n"); 199 else if (err) 200 return err; 201 } 202 203 /* Don't bother copying flags if none are set */ 204 if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK)) 205 return 0; 206 207 err = ovl_real_fileattr_get(new, &newfa); 208 if (err) { 209 /* 210 * Returning an error if upper doesn't support fileattr will 211 * result in a regression, so revert to the old behavior. 212 */ 213 if (err == -ENOTTY || err == -EINVAL) { 214 pr_warn_once("copying fileattr: no support on upper\n"); 215 return 0; 216 } 217 pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n", 218 new->dentry, err); 219 return err; 220 } 221 222 BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL); 223 newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK; 224 newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK); 225 226 BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON); 227 newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK; 228 newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK); 229 230 return ovl_real_fileattr_set(new, &newfa); 231} 232 233static int ovl_verify_area(loff_t pos, loff_t pos2, loff_t len, loff_t totlen) 234{ 235 loff_t tmp; 236 237 if (pos != pos2) 238 return -EIO; 239 if (pos < 0 || len < 0 || totlen < 0) 240 return -EIO; 241 if (check_add_overflow(pos, len, &tmp)) 242 return -EIO; 243 return 0; 244} 245 246static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, 247 struct file *new_file, loff_t len) 248{ 249 struct path datapath; 250 struct file *old_file; 251 loff_t old_pos = 0; 252 loff_t new_pos = 0; 253 loff_t cloned; 254 loff_t data_pos = -1; 255 loff_t hole_len; 256 bool skip_hole = false; 257 int error = 0; 258 259 ovl_path_lowerdata(dentry, &datapath); 260 if (WARN_ON_ONCE(datapath.dentry == NULL) || 261 WARN_ON_ONCE(len < 0)) 262 return -EIO; 263 264 old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY); 265 if (IS_ERR(old_file)) 266 return PTR_ERR(old_file); 267 268 /* Try to use clone_file_range to clone up within the same fs */ 269 cloned = vfs_clone_file_range(old_file, 0, new_file, 0, len, 0); 270 if (cloned == len) 271 goto out_fput; 272 273 /* Couldn't clone, so now we try to copy the data */ 274 error = rw_verify_area(READ, old_file, &old_pos, len); 275 if (!error) 276 error = rw_verify_area(WRITE, new_file, &new_pos, len); 277 if (error) 278 goto out_fput; 279 280 /* Check if lower fs supports seek operation */ 281 if (old_file->f_mode & FMODE_LSEEK) 282 skip_hole = true; 283 284 while (len) { 285 size_t this_len = OVL_COPY_UP_CHUNK_SIZE; 286 ssize_t bytes; 287 288 if (len < this_len) 289 this_len = len; 290 291 if (signal_pending_state(TASK_KILLABLE, current)) { 292 error = -EINTR; 293 break; 294 } 295 296 /* 297 * Fill zero for hole will cost unnecessary disk space 298 * and meanwhile slow down the copy-up speed, so we do 299 * an optimization for hole during copy-up, it relies 300 * on SEEK_DATA implementation in lower fs so if lower 301 * fs does not support it, copy-up will behave as before. 302 * 303 * Detail logic of hole detection as below: 304 * When we detect next data position is larger than current 305 * position we will skip that hole, otherwise we copy 306 * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually, 307 * it may not recognize all kind of holes and sometimes 308 * only skips partial of hole area. However, it will be 309 * enough for most of the use cases. 310 * 311 * We do not hold upper sb_writers throughout the loop to avert 312 * lockdep warning with llseek of lower file in nested overlay: 313 * - upper sb_writers 314 * -- lower ovl_inode_lock (ovl_llseek) 315 */ 316 if (skip_hole && data_pos < old_pos) { 317 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA); 318 if (data_pos > old_pos) { 319 hole_len = data_pos - old_pos; 320 len -= hole_len; 321 old_pos = new_pos = data_pos; 322 continue; 323 } else if (data_pos == -ENXIO) { 324 break; 325 } else if (data_pos < 0) { 326 skip_hole = false; 327 } 328 } 329 330 error = ovl_verify_area(old_pos, new_pos, this_len, len); 331 if (error) 332 break; 333 334 bytes = do_splice_direct(old_file, &old_pos, 335 new_file, &new_pos, 336 this_len, SPLICE_F_MOVE); 337 if (bytes <= 0) { 338 error = bytes; 339 break; 340 } 341 WARN_ON(old_pos != new_pos); 342 343 len -= bytes; 344 } 345 if (!error && ovl_should_sync(ofs)) 346 error = vfs_fsync(new_file, 0); 347out_fput: 348 fput(old_file); 349 return error; 350} 351 352static int ovl_set_size(struct ovl_fs *ofs, 353 struct dentry *upperdentry, struct kstat *stat) 354{ 355 struct iattr attr = { 356 .ia_valid = ATTR_SIZE, 357 .ia_size = stat->size, 358 }; 359 360 return ovl_do_notify_change(ofs, upperdentry, &attr); 361} 362 363static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry, 364 struct kstat *stat) 365{ 366 struct iattr attr = { 367 .ia_valid = 368 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_CTIME, 369 .ia_atime = stat->atime, 370 .ia_mtime = stat->mtime, 371 }; 372 373 return ovl_do_notify_change(ofs, upperdentry, &attr); 374} 375 376int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry, 377 struct kstat *stat) 378{ 379 int err = 0; 380 381 if (!S_ISLNK(stat->mode)) { 382 struct iattr attr = { 383 .ia_valid = ATTR_MODE, 384 .ia_mode = stat->mode, 385 }; 386 err = ovl_do_notify_change(ofs, upperdentry, &attr); 387 } 388 if (!err) { 389 struct iattr attr = { 390 .ia_valid = ATTR_UID | ATTR_GID, 391 .ia_vfsuid = VFSUIDT_INIT(stat->uid), 392 .ia_vfsgid = VFSGIDT_INIT(stat->gid), 393 }; 394 err = ovl_do_notify_change(ofs, upperdentry, &attr); 395 } 396 if (!err) 397 ovl_set_timestamps(ofs, upperdentry, stat); 398 399 return err; 400} 401 402struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, 403 bool is_upper) 404{ 405 struct ovl_fh *fh; 406 int fh_type, dwords; 407 int buflen = MAX_HANDLE_SZ; 408 uuid_t *uuid = &real->d_sb->s_uuid; 409 int err; 410 411 /* Make sure the real fid stays 32bit aligned */ 412 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4); 413 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255); 414 415 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL); 416 if (!fh) 417 return ERR_PTR(-ENOMEM); 418 419 /* 420 * We encode a non-connectable file handle for non-dir, because we 421 * only need to find the lower inode number and we don't want to pay 422 * the price or reconnecting the dentry. 423 */ 424 dwords = buflen >> 2; 425 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0); 426 buflen = (dwords << 2); 427 428 err = -EIO; 429 if (WARN_ON(fh_type < 0) || 430 WARN_ON(buflen > MAX_HANDLE_SZ) || 431 WARN_ON(fh_type == FILEID_INVALID)) 432 goto out_err; 433 434 fh->fb.version = OVL_FH_VERSION; 435 fh->fb.magic = OVL_FH_MAGIC; 436 fh->fb.type = fh_type; 437 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN; 438 /* 439 * When we will want to decode an overlay dentry from this handle 440 * and all layers are on the same fs, if we get a disconncted real 441 * dentry when we decode fid, the only way to tell if we should assign 442 * it to upperdentry or to lowerstack is by checking this flag. 443 */ 444 if (is_upper) 445 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER; 446 fh->fb.len = sizeof(fh->fb) + buflen; 447 if (ovl_origin_uuid(ofs)) 448 fh->fb.uuid = *uuid; 449 450 return fh; 451 452out_err: 453 kfree(fh); 454 return ERR_PTR(err); 455} 456 457struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin) 458{ 459 /* 460 * When lower layer doesn't support export operations store a 'null' fh, 461 * so we can use the overlay.origin xattr to distignuish between a copy 462 * up and a pure upper inode. 463 */ 464 if (!ovl_can_decode_fh(origin->d_sb)) 465 return NULL; 466 467 return ovl_encode_real_fh(ofs, origin, false); 468} 469 470int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh, 471 struct dentry *upper) 472{ 473 int err; 474 475 /* 476 * Do not fail when upper doesn't support xattrs. 477 */ 478 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf, 479 fh ? fh->fb.len : 0, 0); 480 481 /* Ignore -EPERM from setting "user.*" on symlink/special */ 482 return err == -EPERM ? 0 : err; 483} 484 485/* Store file handle of @upper dir in @index dir entry */ 486static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper, 487 struct dentry *index) 488{ 489 const struct ovl_fh *fh; 490 int err; 491 492 fh = ovl_encode_real_fh(ofs, upper, true); 493 if (IS_ERR(fh)) 494 return PTR_ERR(fh); 495 496 err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len); 497 498 kfree(fh); 499 return err; 500} 501 502/* 503 * Create and install index entry. 504 * 505 * Caller must hold i_mutex on indexdir. 506 */ 507static int ovl_create_index(struct dentry *dentry, const struct ovl_fh *fh, 508 struct dentry *upper) 509{ 510 struct ovl_fs *ofs = OVL_FS(dentry->d_sb); 511 struct dentry *indexdir = ovl_indexdir(dentry->d_sb); 512 struct inode *dir = d_inode(indexdir); 513 struct dentry *index = NULL; 514 struct dentry *temp = NULL; 515 struct qstr name = { }; 516 int err; 517 518 /* 519 * For now this is only used for creating index entry for directories, 520 * because non-dir are copied up directly to index and then hardlinked 521 * to upper dir. 522 * 523 * TODO: implement create index for non-dir, so we can call it when 524 * encoding file handle for non-dir in case index does not exist. 525 */ 526 if (WARN_ON(!d_is_dir(dentry))) 527 return -EIO; 528 529 /* Directory not expected to be indexed before copy up */ 530 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) 531 return -EIO; 532 533 err = ovl_get_index_name_fh(fh, &name); 534 if (err) 535 return err; 536 537 temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0)); 538 err = PTR_ERR(temp); 539 if (IS_ERR(temp)) 540 goto free_name; 541 542 err = ovl_set_upper_fh(ofs, upper, temp); 543 if (err) 544 goto out; 545 546 index = ovl_lookup_upper(ofs, name.name, indexdir, name.len); 547 if (IS_ERR(index)) { 548 err = PTR_ERR(index); 549 } else { 550 err = ovl_do_rename(ofs, dir, temp, dir, index, 0); 551 dput(index); 552 } 553out: 554 if (err) 555 ovl_cleanup(ofs, dir, temp); 556 dput(temp); 557free_name: 558 kfree(name.name); 559 return err; 560} 561 562struct ovl_copy_up_ctx { 563 struct dentry *parent; 564 struct dentry *dentry; 565 struct path lowerpath; 566 struct kstat stat; 567 struct kstat pstat; 568 const char *link; 569 struct dentry *destdir; 570 struct qstr destname; 571 struct dentry *workdir; 572 const struct ovl_fh *origin_fh; 573 bool origin; 574 bool indexed; 575 bool metacopy; 576 bool metacopy_digest; 577}; 578 579static int ovl_link_up(struct ovl_copy_up_ctx *c) 580{ 581 int err; 582 struct dentry *upper; 583 struct dentry *upperdir = ovl_dentry_upper(c->parent); 584 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 585 struct inode *udir = d_inode(upperdir); 586 587 ovl_start_write(c->dentry); 588 589 /* Mark parent "impure" because it may now contain non-pure upper */ 590 err = ovl_set_impure(c->parent, upperdir); 591 if (err) 592 goto out; 593 594 err = ovl_set_nlink_lower(c->dentry); 595 if (err) 596 goto out; 597 598 inode_lock_nested(udir, I_MUTEX_PARENT); 599 upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir, 600 c->dentry->d_name.len); 601 err = PTR_ERR(upper); 602 if (!IS_ERR(upper)) { 603 err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper); 604 dput(upper); 605 606 if (!err) { 607 /* Restore timestamps on parent (best effort) */ 608 ovl_set_timestamps(ofs, upperdir, &c->pstat); 609 ovl_dentry_set_upper_alias(c->dentry); 610 ovl_dentry_update_reval(c->dentry, upper); 611 } 612 } 613 inode_unlock(udir); 614 if (err) 615 goto out; 616 617 err = ovl_set_nlink_upper(c->dentry); 618 619out: 620 ovl_end_write(c->dentry); 621 return err; 622} 623 624static int ovl_copy_up_data(struct ovl_copy_up_ctx *c, const struct path *temp) 625{ 626 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 627 struct file *new_file; 628 int err; 629 630 if (!S_ISREG(c->stat.mode) || c->metacopy || !c->stat.size) 631 return 0; 632 633 new_file = ovl_path_open(temp, O_LARGEFILE | O_WRONLY); 634 if (IS_ERR(new_file)) 635 return PTR_ERR(new_file); 636 637 err = ovl_copy_up_file(ofs, c->dentry, new_file, c->stat.size); 638 fput(new_file); 639 640 return err; 641} 642 643static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp) 644{ 645 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 646 struct inode *inode = d_inode(c->dentry); 647 struct path upperpath = { .mnt = ovl_upper_mnt(ofs), .dentry = temp }; 648 int err; 649 650 err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp); 651 if (err) 652 return err; 653 654 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK && 655 (S_ISREG(c->stat.mode) || S_ISDIR(c->stat.mode))) { 656 /* 657 * Copy the fileattr inode flags that are the source of already 658 * copied i_flags 659 */ 660 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath); 661 if (err) 662 return err; 663 } 664 665 /* 666 * Store identifier of lower inode in upper inode xattr to 667 * allow lookup of the copy up origin inode. 668 * 669 * Don't set origin when we are breaking the association with a lower 670 * hard link. 671 */ 672 if (c->origin) { 673 err = ovl_set_origin_fh(ofs, c->origin_fh, temp); 674 if (err) 675 return err; 676 } 677 678 if (c->metacopy) { 679 struct path lowerdatapath; 680 struct ovl_metacopy metacopy_data = OVL_METACOPY_INIT; 681 682 ovl_path_lowerdata(c->dentry, &lowerdatapath); 683 if (WARN_ON_ONCE(lowerdatapath.dentry == NULL)) 684 return -EIO; 685 err = ovl_get_verity_digest(ofs, &lowerdatapath, &metacopy_data); 686 if (err) 687 return err; 688 689 if (metacopy_data.digest_algo) 690 c->metacopy_digest = true; 691 692 err = ovl_set_metacopy_xattr(ofs, temp, &metacopy_data); 693 if (err) 694 return err; 695 } 696 697 inode_lock(temp->d_inode); 698 if (S_ISREG(c->stat.mode)) 699 err = ovl_set_size(ofs, temp, &c->stat); 700 if (!err) 701 err = ovl_set_attr(ofs, temp, &c->stat); 702 inode_unlock(temp->d_inode); 703 704 return err; 705} 706 707struct ovl_cu_creds { 708 const struct cred *old; 709 struct cred *new; 710}; 711 712static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc) 713{ 714 int err; 715 716 cc->old = cc->new = NULL; 717 err = security_inode_copy_up(dentry, &cc->new); 718 if (err < 0) 719 return err; 720 721 if (cc->new) 722 cc->old = override_creds(cc->new); 723 724 return 0; 725} 726 727static void ovl_revert_cu_creds(struct ovl_cu_creds *cc) 728{ 729 if (cc->new) { 730 revert_creds(cc->old); 731 put_cred(cc->new); 732 } 733} 734 735/* 736 * Copyup using workdir to prepare temp file. Used when copying up directories, 737 * special files or when upper fs doesn't support O_TMPFILE. 738 */ 739static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) 740{ 741 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 742 struct inode *inode; 743 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir); 744 struct path path = { .mnt = ovl_upper_mnt(ofs) }; 745 struct dentry *temp, *upper, *trap; 746 struct ovl_cu_creds cc; 747 int err; 748 struct ovl_cattr cattr = { 749 /* Can't properly set mode on creation because of the umask */ 750 .mode = c->stat.mode & S_IFMT, 751 .rdev = c->stat.rdev, 752 .link = c->link 753 }; 754 755 err = ovl_prep_cu_creds(c->dentry, &cc); 756 if (err) 757 return err; 758 759 ovl_start_write(c->dentry); 760 inode_lock(wdir); 761 temp = ovl_create_temp(ofs, c->workdir, &cattr); 762 inode_unlock(wdir); 763 ovl_end_write(c->dentry); 764 ovl_revert_cu_creds(&cc); 765 766 if (IS_ERR(temp)) 767 return PTR_ERR(temp); 768 769 /* 770 * Copy up data first and then xattrs. Writing data after 771 * xattrs will remove security.capability xattr automatically. 772 */ 773 path.dentry = temp; 774 err = ovl_copy_up_data(c, &path); 775 /* 776 * We cannot hold lock_rename() throughout this helper, because of 777 * lock ordering with sb_writers, which shouldn't be held when calling 778 * ovl_copy_up_data(), so lock workdir and destdir and make sure that 779 * temp wasn't moved before copy up completion or cleanup. 780 */ 781 ovl_start_write(c->dentry); 782 trap = lock_rename(c->workdir, c->destdir); 783 if (trap || temp->d_parent != c->workdir) { 784 /* temp or workdir moved underneath us? abort without cleanup */ 785 dput(temp); 786 err = -EIO; 787 if (IS_ERR(trap)) 788 goto out; 789 goto unlock; 790 } else if (err) { 791 goto cleanup; 792 } 793 794 err = ovl_copy_up_metadata(c, temp); 795 if (err) 796 goto cleanup; 797 798 if (S_ISDIR(c->stat.mode) && c->indexed) { 799 err = ovl_create_index(c->dentry, c->origin_fh, temp); 800 if (err) 801 goto cleanup; 802 } 803 804 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir, 805 c->destname.len); 806 err = PTR_ERR(upper); 807 if (IS_ERR(upper)) 808 goto cleanup; 809 810 err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0); 811 dput(upper); 812 if (err) 813 goto cleanup; 814 815 inode = d_inode(c->dentry); 816 if (c->metacopy_digest) 817 ovl_set_flag(OVL_HAS_DIGEST, inode); 818 else 819 ovl_clear_flag(OVL_HAS_DIGEST, inode); 820 ovl_clear_flag(OVL_VERIFIED_DIGEST, inode); 821 822 if (!c->metacopy) 823 ovl_set_upperdata(inode); 824 ovl_inode_update(inode, temp); 825 if (S_ISDIR(inode->i_mode)) 826 ovl_set_flag(OVL_WHITEOUTS, inode); 827unlock: 828 unlock_rename(c->workdir, c->destdir); 829out: 830 ovl_end_write(c->dentry); 831 832 return err; 833 834cleanup: 835 ovl_cleanup(ofs, wdir, temp); 836 dput(temp); 837 goto unlock; 838} 839 840/* Copyup using O_TMPFILE which does not require cross dir locking */ 841static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) 842{ 843 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 844 struct inode *udir = d_inode(c->destdir); 845 struct dentry *temp, *upper; 846 struct file *tmpfile; 847 struct ovl_cu_creds cc; 848 int err; 849 850 err = ovl_prep_cu_creds(c->dentry, &cc); 851 if (err) 852 return err; 853 854 ovl_start_write(c->dentry); 855 tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode); 856 ovl_end_write(c->dentry); 857 ovl_revert_cu_creds(&cc); 858 if (IS_ERR(tmpfile)) 859 return PTR_ERR(tmpfile); 860 861 temp = tmpfile->f_path.dentry; 862 if (!c->metacopy && c->stat.size) { 863 err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size); 864 if (err) 865 goto out_fput; 866 } 867 868 ovl_start_write(c->dentry); 869 870 err = ovl_copy_up_metadata(c, temp); 871 if (err) 872 goto out; 873 874 inode_lock_nested(udir, I_MUTEX_PARENT); 875 876 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir, 877 c->destname.len); 878 err = PTR_ERR(upper); 879 if (!IS_ERR(upper)) { 880 err = ovl_do_link(ofs, temp, udir, upper); 881 dput(upper); 882 } 883 inode_unlock(udir); 884 885 if (err) 886 goto out; 887 888 if (c->metacopy_digest) 889 ovl_set_flag(OVL_HAS_DIGEST, d_inode(c->dentry)); 890 else 891 ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry)); 892 ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry)); 893 894 if (!c->metacopy) 895 ovl_set_upperdata(d_inode(c->dentry)); 896 ovl_inode_update(d_inode(c->dentry), dget(temp)); 897 898out: 899 ovl_end_write(c->dentry); 900out_fput: 901 fput(tmpfile); 902 return err; 903} 904 905/* 906 * Copy up a single dentry 907 * 908 * All renames start with copy up of source if necessary. The actual 909 * rename will only proceed once the copy up was successful. Copy up uses 910 * upper parent i_mutex for exclusion. Since rename can change d_parent it 911 * is possible that the copy up will lock the old parent. At that point 912 * the file will have already been copied up anyway. 913 */ 914static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) 915{ 916 int err; 917 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 918 struct dentry *origin = c->lowerpath.dentry; 919 struct ovl_fh *fh = NULL; 920 bool to_index = false; 921 922 /* 923 * Indexed non-dir is copied up directly to the index entry and then 924 * hardlinked to upper dir. Indexed dir is copied up to indexdir, 925 * then index entry is created and then copied up dir installed. 926 * Copying dir up to indexdir instead of workdir simplifies locking. 927 */ 928 if (ovl_need_index(c->dentry)) { 929 c->indexed = true; 930 if (S_ISDIR(c->stat.mode)) 931 c->workdir = ovl_indexdir(c->dentry->d_sb); 932 else 933 to_index = true; 934 } 935 936 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) { 937 fh = ovl_get_origin_fh(ofs, origin); 938 if (IS_ERR(fh)) 939 return PTR_ERR(fh); 940 941 /* origin_fh may be NULL */ 942 c->origin_fh = fh; 943 c->origin = true; 944 } 945 946 if (to_index) { 947 c->destdir = ovl_indexdir(c->dentry->d_sb); 948 err = ovl_get_index_name(ofs, origin, &c->destname); 949 if (err) 950 goto out_free_fh; 951 } else if (WARN_ON(!c->parent)) { 952 /* Disconnected dentry must be copied up to index dir */ 953 err = -EIO; 954 goto out_free_fh; 955 } else { 956 /* 957 * c->dentry->d_name is stabilzed by ovl_copy_up_start(), 958 * because if we got here, it means that c->dentry has no upper 959 * alias and changing ->d_name means going through ovl_rename() 960 * that will call ovl_copy_up() on source and target dentry. 961 */ 962 c->destname = c->dentry->d_name; 963 /* 964 * Mark parent "impure" because it may now contain non-pure 965 * upper 966 */ 967 ovl_start_write(c->dentry); 968 err = ovl_set_impure(c->parent, c->destdir); 969 ovl_end_write(c->dentry); 970 if (err) 971 goto out_free_fh; 972 } 973 974 /* Should we copyup with O_TMPFILE or with workdir? */ 975 if (S_ISREG(c->stat.mode) && ofs->tmpfile) 976 err = ovl_copy_up_tmpfile(c); 977 else 978 err = ovl_copy_up_workdir(c); 979 if (err) 980 goto out; 981 982 if (c->indexed) 983 ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); 984 985 ovl_start_write(c->dentry); 986 if (to_index) { 987 /* Initialize nlink for copy up of disconnected dentry */ 988 err = ovl_set_nlink_upper(c->dentry); 989 } else { 990 struct inode *udir = d_inode(c->destdir); 991 992 /* Restore timestamps on parent (best effort) */ 993 inode_lock(udir); 994 ovl_set_timestamps(ofs, c->destdir, &c->pstat); 995 inode_unlock(udir); 996 997 ovl_dentry_set_upper_alias(c->dentry); 998 ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry)); 999 } 1000 ovl_end_write(c->dentry); 1001 1002out: 1003 if (to_index) 1004 kfree(c->destname.name); 1005out_free_fh: 1006 kfree(fh); 1007 return err; 1008} 1009 1010static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode, 1011 int flags) 1012{ 1013 struct ovl_fs *ofs = OVL_FS(dentry->d_sb); 1014 1015 if (!ofs->config.metacopy) 1016 return false; 1017 1018 if (!S_ISREG(mode)) 1019 return false; 1020 1021 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC))) 1022 return false; 1023 1024 /* Fall back to full copy if no fsverity on source data and we require verity */ 1025 if (ofs->config.verity_mode == OVL_VERITY_REQUIRE) { 1026 struct path lowerdata; 1027 1028 ovl_path_lowerdata(dentry, &lowerdata); 1029 1030 if (WARN_ON_ONCE(lowerdata.dentry == NULL) || 1031 ovl_ensure_verity_loaded(&lowerdata) || 1032 !fsverity_active(d_inode(lowerdata.dentry))) { 1033 return false; 1034 } 1035 } 1036 1037 return true; 1038} 1039 1040static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value) 1041{ 1042 ssize_t res; 1043 char *buf; 1044 1045 res = ovl_do_getxattr(path, name, NULL, 0); 1046 if (res == -ENODATA || res == -EOPNOTSUPP) 1047 res = 0; 1048 1049 if (res > 0) { 1050 buf = kzalloc(res, GFP_KERNEL); 1051 if (!buf) 1052 return -ENOMEM; 1053 1054 res = ovl_do_getxattr(path, name, buf, res); 1055 if (res < 0) 1056 kfree(buf); 1057 else 1058 *value = buf; 1059 } 1060 return res; 1061} 1062 1063/* Copy up data of an inode which was copied up metadata only in the past. */ 1064static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) 1065{ 1066 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); 1067 struct path upperpath; 1068 int err; 1069 char *capability = NULL; 1070 ssize_t cap_size; 1071 1072 ovl_path_upper(c->dentry, &upperpath); 1073 if (WARN_ON(upperpath.dentry == NULL)) 1074 return -EIO; 1075 1076 if (c->stat.size) { 1077 err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS, 1078 &capability); 1079 if (cap_size < 0) 1080 goto out; 1081 } 1082 1083 err = ovl_copy_up_data(c, &upperpath); 1084 if (err) 1085 goto out_free; 1086 1087 /* 1088 * Writing to upper file will clear security.capability xattr. We 1089 * don't want that to happen for normal copy-up operation. 1090 */ 1091 ovl_start_write(c->dentry); 1092 if (capability) { 1093 err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS, 1094 capability, cap_size, 0); 1095 } 1096 if (!err) { 1097 err = ovl_removexattr(ofs, upperpath.dentry, 1098 OVL_XATTR_METACOPY); 1099 } 1100 ovl_end_write(c->dentry); 1101 if (err) 1102 goto out_free; 1103 1104 ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry)); 1105 ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry)); 1106 ovl_set_upperdata(d_inode(c->dentry)); 1107out_free: 1108 kfree(capability); 1109out: 1110 return err; 1111} 1112 1113static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, 1114 int flags) 1115{ 1116 int err; 1117 DEFINE_DELAYED_CALL(done); 1118 struct path parentpath; 1119 struct ovl_copy_up_ctx ctx = { 1120 .parent = parent, 1121 .dentry = dentry, 1122 .workdir = ovl_workdir(dentry), 1123 }; 1124 1125 if (WARN_ON(!ctx.workdir)) 1126 return -EROFS; 1127 1128 ovl_path_lower(dentry, &ctx.lowerpath); 1129 err = vfs_getattr(&ctx.lowerpath, &ctx.stat, 1130 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); 1131 if (err) 1132 return err; 1133 1134 if (!kuid_has_mapping(current_user_ns(), ctx.stat.uid) || 1135 !kgid_has_mapping(current_user_ns(), ctx.stat.gid)) 1136 return -EOVERFLOW; 1137 1138 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags); 1139 1140 if (parent) { 1141 ovl_path_upper(parent, &parentpath); 1142 ctx.destdir = parentpath.dentry; 1143 1144 err = vfs_getattr(&parentpath, &ctx.pstat, 1145 STATX_ATIME | STATX_MTIME, 1146 AT_STATX_SYNC_AS_STAT); 1147 if (err) 1148 return err; 1149 } 1150 1151 /* maybe truncate regular file. this has no effect on dirs */ 1152 if (flags & O_TRUNC) 1153 ctx.stat.size = 0; 1154 1155 if (S_ISLNK(ctx.stat.mode)) { 1156 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); 1157 if (IS_ERR(ctx.link)) 1158 return PTR_ERR(ctx.link); 1159 } 1160 1161 err = ovl_copy_up_start(dentry, flags); 1162 /* err < 0: interrupted, err > 0: raced with another copy-up */ 1163 if (unlikely(err)) { 1164 if (err > 0) 1165 err = 0; 1166 } else { 1167 if (!ovl_dentry_upper(dentry)) 1168 err = ovl_do_copy_up(&ctx); 1169 if (!err && parent && !ovl_dentry_has_upper_alias(dentry)) 1170 err = ovl_link_up(&ctx); 1171 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags)) 1172 err = ovl_copy_up_meta_inode_data(&ctx); 1173 ovl_copy_up_end(dentry); 1174 } 1175 do_delayed_call(&done); 1176 1177 return err; 1178} 1179 1180static int ovl_copy_up_flags(struct dentry *dentry, int flags) 1181{ 1182 int err = 0; 1183 const struct cred *old_cred; 1184 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED); 1185 1186 /* 1187 * With NFS export, copy up can get called for a disconnected non-dir. 1188 * In this case, we will copy up lower inode to index dir without 1189 * linking it to upper dir. 1190 */ 1191 if (WARN_ON(disconnected && d_is_dir(dentry))) 1192 return -EIO; 1193 1194 /* 1195 * We may not need lowerdata if we are only doing metacopy up, but it is 1196 * not very important to optimize this case, so do lazy lowerdata lookup 1197 * before any copy up, so we can do it before taking ovl_inode_lock(). 1198 */ 1199 err = ovl_verify_lowerdata(dentry); 1200 if (err) 1201 return err; 1202 1203 old_cred = ovl_override_creds(dentry->d_sb); 1204 while (!err) { 1205 struct dentry *next; 1206 struct dentry *parent = NULL; 1207 1208 if (ovl_already_copied_up(dentry, flags)) 1209 break; 1210 1211 next = dget(dentry); 1212 /* find the topmost dentry not yet copied up */ 1213 for (; !disconnected;) { 1214 parent = dget_parent(next); 1215 1216 if (ovl_dentry_upper(parent)) 1217 break; 1218 1219 dput(next); 1220 next = parent; 1221 } 1222 1223 err = ovl_copy_up_one(parent, next, flags); 1224 1225 dput(parent); 1226 dput(next); 1227 } 1228 revert_creds(old_cred); 1229 1230 return err; 1231} 1232 1233static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) 1234{ 1235 /* Copy up of disconnected dentry does not set upper alias */ 1236 if (ovl_already_copied_up(dentry, flags)) 1237 return false; 1238 1239 if (special_file(d_inode(dentry)->i_mode)) 1240 return false; 1241 1242 if (!ovl_open_flags_need_copy_up(flags)) 1243 return false; 1244 1245 return true; 1246} 1247 1248int ovl_maybe_copy_up(struct dentry *dentry, int flags) 1249{ 1250 if (!ovl_open_need_copy_up(dentry, flags)) 1251 return 0; 1252 1253 return ovl_copy_up_flags(dentry, flags); 1254} 1255 1256int ovl_copy_up_with_data(struct dentry *dentry) 1257{ 1258 return ovl_copy_up_flags(dentry, O_WRONLY); 1259} 1260 1261int ovl_copy_up(struct dentry *dentry) 1262{ 1263 return ovl_copy_up_flags(dentry, 0); 1264} 1265