1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * 4 * Copyright (C) 2011 Novell Inc. 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/uuid.h> 9 #include <linux/fs.h> 10 #include <linux/fsverity.h> 11 #include <linux/namei.h> 12 #include <linux/posix_acl.h> 13 #include <linux/posix_acl_xattr.h> 14 #include "ovl_entry.h" 15 16 #undef pr_fmt 17 #define pr_fmt(fmt) "overlayfs: " fmt 18 19 #define OVL_MAX_NESTING FILESYSTEM_MAX_STACK_DEPTH 20 21 enum ovl_path_type { 22 __OVL_PATH_UPPER = (1 << 0), 23 __OVL_PATH_MERGE = (1 << 1), 24 __OVL_PATH_ORIGIN = (1 << 2), 25 }; 26 27 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 28 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 29 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 30 31 #define OVL_XATTR_NAMESPACE "overlay." 32 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE 33 #define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) 34 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE 35 #define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1) 36 37 #define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE 38 #define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1) 39 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX 40 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1) 41 #define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX 42 #define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1) 43 44 enum ovl_xattr { 45 OVL_XATTR_OPAQUE, 46 OVL_XATTR_REDIRECT, 47 OVL_XATTR_ORIGIN, 48 OVL_XATTR_IMPURE, 49 OVL_XATTR_NLINK, 50 OVL_XATTR_UPPER, 51 OVL_XATTR_UUID, 52 OVL_XATTR_METACOPY, 53 OVL_XATTR_PROTATTR, 54 OVL_XATTR_XWHITEOUT, 55 }; 56 57 enum ovl_inode_flag { 58 /* Pure upper dir that may contain non pure upper entries */ 59 OVL_IMPURE, 60 /* Non-merge dir that may contain whiteout entries */ 61 OVL_WHITEOUTS, 62 OVL_INDEX, 63 OVL_UPPERDATA, 64 /* Inode number will remain constant over copy up. */ 65 OVL_CONST_INO, 66 OVL_HAS_DIGEST, 67 OVL_VERIFIED_DIGEST, 68 }; 69 70 enum ovl_entry_flag { 71 OVL_E_UPPER_ALIAS, 72 OVL_E_OPAQUE, 73 OVL_E_CONNECTED, 74 /* Lower stack may contain xwhiteout entries */ 75 OVL_E_XWHITEOUTS, 76 }; 77 78 enum { 79 OVL_REDIRECT_OFF, /* "off" mode is never used. In effect */ 80 OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */ 81 OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */ 82 OVL_REDIRECT_ON, 83 }; 84 85 enum { 86 OVL_UUID_OFF, 87 OVL_UUID_NULL, 88 OVL_UUID_AUTO, 89 OVL_UUID_ON, 90 }; 91 92 enum { 93 OVL_XINO_OFF, 94 OVL_XINO_AUTO, 95 OVL_XINO_ON, 96 }; 97 98 enum { 99 OVL_VERITY_OFF, 100 OVL_VERITY_ON, 101 OVL_VERITY_REQUIRE, 102 }; 103 104 enum { 105 OVL_FSYNC_VOLATILE, 106 OVL_FSYNC_AUTO, 107 OVL_FSYNC_STRICT, 108 }; 109 110 /* 111 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 112 * where: 113 * origin.fh - exported file handle of the lower file 114 * origin.uuid - uuid of the lower filesystem 115 */ 116 #define OVL_FH_VERSION 0 117 #define OVL_FH_MAGIC 0xfb 118 119 /* CPU byte order required for fid decoding: */ 120 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 121 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 122 /* Is the real inode encoded in fid an upper inode? */ 123 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 124 125 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 126 OVL_FH_FLAG_PATH_UPPER) 127 128 #if defined(__LITTLE_ENDIAN) 129 #define OVL_FH_FLAG_CPU_ENDIAN 0 130 #elif defined(__BIG_ENDIAN) 131 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 132 #else 133 #error Endianness not defined 134 #endif 135 136 /* The type used to be returned by overlay exportfs for misaligned fid */ 137 #define OVL_FILEID_V0 0xfb 138 /* The type returned by overlay exportfs for 32bit aligned fid */ 139 #define OVL_FILEID_V1 0xf8 140 141 /* On-disk format for "origin" file handle */ 142 struct ovl_fb { 143 u8 version; /* 0 */ 144 u8 magic; /* 0xfb */ 145 u8 len; /* size of this header + size of fid */ 146 u8 flags; /* OVL_FH_FLAG_* */ 147 u8 type; /* fid_type of fid */ 148 uuid_t uuid; /* uuid of filesystem */ 149 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 150 } __packed; 151 152 /* In-memory and on-wire format for overlay file handle */ 153 struct ovl_fh { 154 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 155 union { 156 struct ovl_fb fb; 157 DECLARE_FLEX_ARRAY(u8, buf); 158 }; 159 } __packed; 160 161 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 162 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 163 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 164 offsetof(struct ovl_fb, fid)) 165 166 /* On-disk format for "metacopy" xattr (if non-zero size) */ 167 struct ovl_metacopy { 168 u8 version; /* 0 */ 169 u8 len; /* size of this header + used digest bytes */ 170 u8 flags; 171 u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */ 172 u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; /* Only the used part on disk */ 173 } __packed; 174 175 #define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy)) 176 #define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE) 177 #define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE } 178 179 static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy) 180 { 181 if (metacopy->len < OVL_METACOPY_MIN_SIZE) 182 return 0; 183 return (int)metacopy->len - OVL_METACOPY_MIN_SIZE; 184 } 185 186 /* No atime modification on underlying */ 187 #define OVL_OPEN_FLAGS (O_NOATIME) 188 189 extern const char *const ovl_xattr_table[][2]; 190 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 191 { 192 return ovl_xattr_table[ox][ofs->config.userxattr]; 193 } 194 195 /* 196 * When changing ownership of an upper object map the intended ownership 197 * according to the upper layer's idmapping. When an upper mount idmaps files 198 * that are stored on-disk as owned by id 1001 to id 1000 this means stat on 199 * this object will report it as being owned by id 1000 when calling stat via 200 * the upper mount. 201 * In order to change ownership of an object so stat reports id 1000 when 202 * called on an idmapped upper mount the value written to disk - i.e., the 203 * value stored in ia_*id - must 1001. The mount mapping helper will thus take 204 * care to map 1000 to 1001. 205 * The mnt idmapping helpers are nops if the upper layer isn't idmapped. 206 */ 207 static inline int ovl_do_notify_change(struct ovl_fs *ofs, 208 struct dentry *upperdentry, 209 struct iattr *attr) 210 { 211 return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL); 212 } 213 214 static inline int ovl_do_rmdir(struct ovl_fs *ofs, 215 struct inode *dir, struct dentry *dentry) 216 { 217 int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL); 218 219 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 220 return err; 221 } 222 223 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir, 224 struct dentry *dentry) 225 { 226 int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL); 227 228 pr_debug("unlink(%pd2) = %i\n", dentry, err); 229 return err; 230 } 231 232 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry, 233 struct inode *dir, struct dentry *new_dentry) 234 { 235 int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir, 236 new_dentry, NULL); 237 238 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 239 return err; 240 } 241 242 static inline int ovl_do_create(struct ovl_fs *ofs, 243 struct inode *dir, struct dentry *dentry, 244 umode_t mode) 245 { 246 int err = vfs_create(ovl_upper_mnt_idmap(ofs), dentry, mode, NULL); 247 248 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 249 return err; 250 } 251 252 static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs, 253 struct inode *dir, 254 struct dentry *dentry, 255 umode_t mode) 256 { 257 struct dentry *ret; 258 259 /* vfs_mkdir() drops @dentry on failure and may replace it on success */ 260 pr_debug("mkdir(%pd2, 0%o)\n", dentry, mode); 261 ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, NULL); 262 pr_debug("...mkdir = %i\n", PTR_ERR_OR_ZERO(ret)); 263 return ret; 264 } 265 266 static inline int ovl_do_mknod(struct ovl_fs *ofs, 267 struct inode *dir, struct dentry *dentry, 268 umode_t mode, dev_t dev) 269 { 270 int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev, NULL); 271 272 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 273 return err; 274 } 275 276 static inline int ovl_do_symlink(struct ovl_fs *ofs, 277 struct inode *dir, struct dentry *dentry, 278 const char *oldname) 279 { 280 int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname, NULL); 281 282 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 283 return err; 284 } 285 286 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name, 287 void *value, size_t size) 288 { 289 int err, len; 290 291 WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb); 292 293 err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry, 294 name, value, size); 295 len = (value && err > 0) ? err : 0; 296 297 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 298 path->dentry, name, min(len, 48), value, size, err); 299 return err; 300 } 301 302 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs, 303 struct dentry *upperdentry, 304 enum ovl_xattr ox, void *value, 305 size_t size) 306 { 307 struct path upperpath = { 308 .dentry = upperdentry, 309 .mnt = ovl_upper_mnt(ofs), 310 }; 311 312 return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size); 313 } 314 315 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs, 316 const struct path *path, 317 enum ovl_xattr ox, void *value, 318 size_t size) 319 { 320 return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size); 321 } 322 323 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 324 const char *name, const void *value, 325 size_t size, int flags) 326 { 327 /* Use vfs_setxattr(), not __vfs_setxattr(): it idmaps the security.capability rootid. */ 328 int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name, 329 value, size, flags); 330 331 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n", 332 dentry, name, min((int)size, 48), value, size, flags, err); 333 return err; 334 } 335 336 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 337 enum ovl_xattr ox, const void *value, 338 size_t size) 339 { 340 return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0); 341 } 342 343 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 344 const char *name) 345 { 346 int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name); 347 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 348 return err; 349 } 350 351 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 352 enum ovl_xattr ox) 353 { 354 return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox)); 355 } 356 357 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry, 358 const char *acl_name, struct posix_acl *acl) 359 { 360 return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl); 361 } 362 363 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry, 364 const char *acl_name) 365 { 366 return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name); 367 } 368 369 static inline int ovl_do_rename_rd(struct renamedata *rd) 370 { 371 int err; 372 373 pr_debug("rename(%pd2, %pd2, 0x%x)\n", rd->old_dentry, rd->new_dentry, 374 rd->flags); 375 err = vfs_rename(rd); 376 if (err) { 377 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 378 rd->old_dentry, rd->new_dentry, err); 379 } 380 return err; 381 } 382 383 static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir, 384 struct dentry *olddentry, struct dentry *newdir, 385 struct dentry *newdentry, unsigned int flags) 386 { 387 struct renamedata rd = { 388 .mnt_idmap = ovl_upper_mnt_idmap(ofs), 389 .old_parent = olddir, 390 .old_dentry = olddentry, 391 .new_parent = newdir, 392 .new_dentry = newdentry, 393 .flags = flags, 394 }; 395 396 return ovl_do_rename_rd(&rd); 397 } 398 399 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs, 400 struct dentry *dentry, umode_t mode) 401 { 402 struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry }; 403 struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, 404 mode, O_LARGEFILE | O_WRONLY, 405 current_cred()); 406 int err = PTR_ERR_OR_ZERO(file); 407 408 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 409 return file; 410 } 411 412 static inline struct dentry *ovl_lookup_upper_unlocked(struct ovl_fs *ofs, 413 const char *name, 414 struct dentry *base, 415 int len) 416 { 417 return lookup_one_unlocked(ovl_upper_mnt_idmap(ofs), 418 &QSTR_LEN(name, len), base); 419 } 420 421 static inline struct dentry *ovl_start_creating_upper(struct ovl_fs *ofs, 422 struct dentry *parent, 423 struct qstr *name) 424 { 425 return start_creating(ovl_upper_mnt_idmap(ofs), 426 parent, name); 427 } 428 429 static inline struct dentry *ovl_start_removing_upper(struct ovl_fs *ofs, 430 struct dentry *parent, 431 struct qstr *name) 432 { 433 return start_removing(ovl_upper_mnt_idmap(ofs), 434 parent, name); 435 } 436 437 static inline bool ovl_open_flags_need_copy_up(int flags) 438 { 439 if (!flags) 440 return false; 441 442 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 443 } 444 445 /* util.c */ 446 int ovl_get_write_access(struct dentry *dentry); 447 void ovl_put_write_access(struct dentry *dentry); 448 void ovl_start_write(struct dentry *dentry); 449 void ovl_end_write(struct dentry *dentry); 450 int ovl_want_write(struct dentry *dentry); 451 void ovl_drop_write(struct dentry *dentry); 452 struct dentry *ovl_workdir(struct dentry *dentry); 453 const struct cred *ovl_override_creds(struct super_block *sb); 454 455 EXTEND_CLASS(override_creds, _ovl, ovl_override_creds(sb), struct super_block *sb) 456 457 #define with_ovl_creds(sb) \ 458 scoped_class(override_creds_ovl, __UNIQUE_ID(label), sb) 459 460 static inline const struct cred *ovl_creds(struct super_block *sb) 461 { 462 return OVL_FS(sb)->creator_cred; 463 } 464 465 int ovl_can_decode_fh(struct super_block *sb); 466 struct dentry *ovl_indexdir(struct super_block *sb); 467 bool ovl_index_all(struct super_block *sb); 468 bool ovl_verify_lower(struct super_block *sb); 469 struct ovl_path *ovl_stack_alloc(unsigned int n); 470 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n); 471 void ovl_stack_put(struct ovl_path *stack, unsigned int n); 472 void ovl_stack_free(struct ovl_path *stack, unsigned int n); 473 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 474 void ovl_free_entry(struct ovl_entry *oe); 475 bool ovl_dentry_remote(struct dentry *dentry); 476 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); 477 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry, 478 struct ovl_entry *oe); 479 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, 480 struct ovl_entry *oe, unsigned int mask); 481 bool ovl_dentry_weird(struct dentry *dentry); 482 483 static inline bool ovl_dentry_casefolded(struct dentry *dentry) 484 { 485 return sb_has_encoding(dentry->d_sb) && IS_CASEFOLDED(d_inode(dentry)); 486 } 487 488 enum ovl_path_type ovl_path_type(struct dentry *dentry); 489 void ovl_path_upper(struct dentry *dentry, struct path *path); 490 void ovl_path_lower(struct dentry *dentry, struct path *path); 491 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 492 struct inode *ovl_i_path_real(struct inode *inode, struct path *path); 493 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 494 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path); 495 struct dentry *ovl_dentry_upper(struct dentry *dentry); 496 struct dentry *ovl_dentry_lower(struct dentry *dentry); 497 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 498 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath); 499 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode); 500 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 501 struct dentry *ovl_dentry_real(struct dentry *dentry); 502 struct dentry *ovl_i_dentry_upper(struct inode *inode); 503 struct inode *ovl_inode_upper(struct inode *inode); 504 struct inode *ovl_inode_lower(struct inode *inode); 505 struct inode *ovl_inode_lowerdata(struct inode *inode); 506 struct inode *ovl_inode_real(struct inode *inode); 507 struct inode *ovl_inode_realdata(struct inode *inode); 508 const char *ovl_lowerdata_redirect(struct inode *inode); 509 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 510 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 511 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 512 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 513 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 514 bool ovl_dentry_is_opaque(struct dentry *dentry); 515 bool ovl_dentry_is_whiteout(struct dentry *dentry); 516 void ovl_dentry_set_opaque(struct dentry *dentry); 517 bool ovl_dentry_has_xwhiteouts(struct dentry *dentry); 518 void ovl_dentry_set_xwhiteouts(struct dentry *dentry); 519 void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs, 520 const struct ovl_layer *layer); 521 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 522 void ovl_dentry_set_upper_alias(struct dentry *dentry); 523 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 524 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 525 bool ovl_has_upperdata(struct inode *inode); 526 void ovl_set_upperdata(struct inode *inode); 527 const char *ovl_dentry_get_redirect(struct dentry *dentry); 528 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 529 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 530 void ovl_dir_modified(struct dentry *dentry, bool impurity); 531 u64 ovl_inode_version_get(struct inode *inode); 532 bool ovl_is_whiteout(struct dentry *dentry); 533 bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path); 534 struct file *ovl_path_open_realfile(const struct file *user_file, 535 const struct path *path, int flags); 536 537 static inline struct file *ovl_path_open(const struct path *path, int flags) 538 { 539 return ovl_path_open_realfile(NULL, path, flags); 540 } 541 542 int ovl_copy_up_start(struct dentry *dentry, int flags); 543 void ovl_copy_up_end(struct dentry *dentry); 544 bool ovl_already_copied_up(struct dentry *dentry, int flags); 545 char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path, 546 enum ovl_xattr ox); 547 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path); 548 bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path); 549 bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs, 550 const struct path *upperpath); 551 552 static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs, 553 struct dentry *upperdentry) 554 { 555 struct path upperpath = { 556 .dentry = upperdentry, 557 .mnt = ovl_upper_mnt(ofs), 558 }; 559 return ovl_path_is_whiteout(ofs, &upperpath); 560 } 561 562 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs, 563 struct dentry *upperdentry) 564 { 565 struct path upperpath = { 566 .dentry = upperdentry, 567 .mnt = ovl_upper_mnt(ofs), 568 }; 569 return ovl_path_check_origin_xattr(ofs, &upperpath); 570 } 571 572 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, 573 enum ovl_xattr ox, const void *value, size_t size, 574 int xerr); 575 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 576 577 static inline int ovl_set_impure_dir(struct dentry *dentry) 578 { 579 return ovl_set_impure(dentry, ovl_dentry_upper(dentry)); 580 } 581 582 bool ovl_inuse_trylock(struct dentry *dentry); 583 void ovl_inuse_unlock(struct dentry *dentry); 584 bool ovl_is_inuse(struct dentry *dentry); 585 bool ovl_need_index(struct dentry *dentry); 586 int ovl_nlink_start(struct dentry *dentry); 587 void ovl_nlink_end(struct dentry *dentry); 588 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path, 589 struct ovl_metacopy *data); 590 int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d, 591 struct ovl_metacopy *metacopy); 592 bool ovl_is_metacopy_dentry(struct dentry *dentry); 593 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding); 594 int ovl_ensure_verity_loaded(const struct path *path); 595 int ovl_validate_verity(struct ovl_fs *ofs, 596 const struct path *metapath, 597 const struct path *datapath); 598 int ovl_get_verity_digest(struct ovl_fs *ofs, const struct path *src, 599 struct ovl_metacopy *metacopy); 600 int ovl_sync_status(struct ovl_fs *ofs); 601 602 static inline void ovl_set_flag(unsigned long flag, struct inode *inode) 603 { 604 set_bit(flag, &OVL_I(inode)->flags); 605 } 606 607 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) 608 { 609 clear_bit(flag, &OVL_I(inode)->flags); 610 } 611 612 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) 613 { 614 return test_bit(flag, &OVL_I(inode)->flags); 615 } 616 617 static inline bool ovl_is_impuredir(struct super_block *sb, 618 struct dentry *upperdentry) 619 { 620 struct ovl_fs *ofs = OVL_FS(sb); 621 struct path upperpath = { 622 .dentry = upperdentry, 623 .mnt = ovl_upper_mnt(ofs), 624 }; 625 626 return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y'; 627 } 628 629 static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs, 630 const struct path *path) 631 { 632 return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE); 633 } 634 635 static inline bool ovl_redirect_follow(struct ovl_fs *ofs) 636 { 637 return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW; 638 } 639 640 static inline bool ovl_redirect_dir(struct ovl_fs *ofs) 641 { 642 return ofs->config.redirect_mode == OVL_REDIRECT_ON; 643 } 644 645 static inline bool ovl_origin_uuid(struct ovl_fs *ofs) 646 { 647 return ofs->config.uuid != OVL_UUID_OFF; 648 } 649 650 static inline bool ovl_has_fsid(struct ovl_fs *ofs) 651 { 652 return ofs->config.uuid == OVL_UUID_ON || 653 ofs->config.uuid == OVL_UUID_AUTO; 654 } 655 656 /* 657 * With xino=auto, we do best effort to keep all inodes on same st_dev and 658 * d_ino consistent with st_ino. 659 * With xino=on, we do the same effort but we warn if we failed. 660 */ 661 static inline bool ovl_xino_warn(struct ovl_fs *ofs) 662 { 663 return ofs->config.xino == OVL_XINO_ON; 664 } 665 666 static inline bool ovl_should_sync(struct ovl_fs *ofs) 667 { 668 return ofs->config.fsync_mode != OVL_FSYNC_VOLATILE; 669 } 670 671 static inline bool ovl_should_sync_metadata(struct ovl_fs *ofs) 672 { 673 return ofs->config.fsync_mode == OVL_FSYNC_STRICT; 674 } 675 676 static inline bool ovl_is_volatile(struct ovl_config *config) 677 { 678 return config->fsync_mode == OVL_FSYNC_VOLATILE; 679 } 680 681 /* 682 * To avoid regressions in existing setups with overlay lower offline changes, 683 * we allow lower changes only if none of the new features are used. 684 */ 685 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs) 686 { 687 return (!ofs->config.index && !ofs->config.metacopy && 688 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs)); 689 } 690 691 /* All layers on same fs? */ 692 static inline bool ovl_same_fs(struct ovl_fs *ofs) 693 { 694 return ofs->xino_mode == 0; 695 } 696 697 /* All overlay inodes have same st_dev? */ 698 static inline bool ovl_same_dev(struct ovl_fs *ofs) 699 { 700 return ofs->xino_mode >= 0; 701 } 702 703 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs) 704 { 705 return ovl_same_dev(ofs) ? ofs->xino_mode : 0; 706 } 707 708 static inline void ovl_inode_lock(struct inode *inode) 709 { 710 mutex_lock(&OVL_I(inode)->lock); 711 } 712 713 static inline int ovl_inode_lock_interruptible(struct inode *inode) 714 { 715 return mutex_lock_interruptible(&OVL_I(inode)->lock); 716 } 717 718 static inline void ovl_inode_unlock(struct inode *inode) 719 { 720 mutex_unlock(&OVL_I(inode)->lock); 721 } 722 723 724 /* namei.c */ 725 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 726 727 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 728 { 729 if (fh_len < sizeof(struct ovl_fh)) 730 return -EINVAL; 731 732 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 733 } 734 735 bool ovl_uuid_match(struct ovl_fs *ofs, const struct super_block *sb, 736 const uuid_t *uuid); 737 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, 738 struct vfsmount *mnt, bool connected); 739 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 740 struct dentry *upperdentry, struct ovl_path **stackp); 741 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 742 enum ovl_xattr ox, const struct ovl_fh *fh, 743 bool is_upper, bool set); 744 int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry, 745 enum ovl_xattr ox, struct dentry *real, 746 bool is_upper, bool set); 747 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index, 748 bool connected); 749 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 750 int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name); 751 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, 752 struct qstr *name); 753 struct dentry *ovl_get_index_origin(struct ovl_fs *ofs, struct dentry *origin); 754 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 755 struct dentry *origin, bool verify); 756 int ovl_path_next(int idx, struct dentry *dentry, struct path *path, 757 const struct ovl_layer **layer); 758 int ovl_verify_lowerdata(struct dentry *dentry); 759 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 760 unsigned int flags); 761 bool ovl_lower_positive(struct dentry *dentry); 762 763 static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper, 764 const struct ovl_fh *fh, bool set) 765 { 766 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set); 767 } 768 769 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 770 struct dentry *origin, bool set) 771 { 772 return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin, 773 false, set); 774 } 775 776 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 777 struct dentry *upper, bool set) 778 { 779 return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper, 780 true, set); 781 } 782 783 /* readdir.c */ 784 extern const struct file_operations ovl_dir_operations; 785 struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 786 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 787 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper, 788 struct list_head *list); 789 void ovl_cache_free(struct list_head *list); 790 void ovl_dir_cache_free(struct inode *inode); 791 int ovl_check_d_type_supported(const struct path *realpath); 792 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent, 793 struct vfsmount *mnt, struct dentry *dentry, int level); 794 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 795 796 /* 797 * Can we iterate real dir directly? 798 * 799 * Non-merge dir may contain whiteouts from a time it was a merge upper, before 800 * lower dir was removed under it and possibly before it was rotated from upper 801 * to lower layer. 802 */ 803 static inline bool ovl_dir_is_real(struct inode *dir) 804 { 805 return !ovl_test_flag(OVL_WHITEOUTS, dir); 806 } 807 808 /* inode.c */ 809 int ovl_set_nlink_upper(struct dentry *dentry); 810 int ovl_set_nlink_lower(struct dentry *dentry); 811 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 812 struct dentry *upperdentry, bool indexed, 813 unsigned int fallback); 814 int ovl_permission(const struct mnt_idmap *idmap, struct inode *inode, 815 int mask); 816 817 #ifdef CONFIG_FS_POSIX_ACL 818 struct posix_acl *do_ovl_get_acl(const struct mnt_idmap *idmap, 819 struct inode *inode, int type, 820 bool rcu, bool noperm); 821 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type, 822 bool rcu) 823 { 824 return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true); 825 } 826 static inline struct posix_acl *ovl_get_acl(const struct mnt_idmap *idmap, 827 struct dentry *dentry, int type) 828 { 829 return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false); 830 } 831 int ovl_set_acl(const struct mnt_idmap *idmap, struct dentry *dentry, 832 struct posix_acl *acl, int type); 833 struct posix_acl *ovl_get_acl_path(const struct path *path, 834 const char *acl_name, bool noperm); 835 #else 836 #define ovl_get_inode_acl NULL 837 #define ovl_get_acl NULL 838 #define ovl_set_acl NULL 839 static inline struct posix_acl *ovl_get_acl_path(const struct path *path, 840 const char *acl_name, 841 bool noperm) 842 { 843 return NULL; 844 } 845 #endif 846 847 int ovl_update_time(struct inode *inode, enum fs_update_time type, 848 unsigned int flags); 849 bool ovl_is_private_xattr(struct super_block *sb, const char *name); 850 851 struct ovl_inode_params { 852 struct inode *newinode; 853 struct dentry *upperdentry; 854 struct ovl_entry *oe; 855 bool index; 856 char *redirect; 857 char *lowerdata_redirect; 858 }; 859 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 860 unsigned long ino, int fsid); 861 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 862 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 863 bool is_upper); 864 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 865 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 866 struct inode *ovl_get_inode(struct super_block *sb, 867 struct ovl_inode_params *oip); 868 void ovl_copyattr(struct inode *to); 869 870 /* vfs fileattr flags read from overlay.protattr xattr to ovl inode */ 871 #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE) 872 /* vfs fileattr flags copied from real to ovl inode */ 873 #define OVL_FATTR_I_FLAGS_MASK (OVL_PROT_I_FLAGS_MASK | S_SYNC | S_NOATIME) 874 /* vfs inode flags copied from real to ovl inode */ 875 #define OVL_COPY_I_FLAGS_MASK (OVL_FATTR_I_FLAGS_MASK | S_CASEFOLD) 876 877 /* 878 * fileattr flags copied from lower to upper inode on copy up. 879 * We cannot copy up immutable/append-only flags, because that would prevent 880 * linking temp inode to upper dir, so we store them in xattr instead. 881 */ 882 #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL) 883 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME) 884 #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL) 885 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE) 886 887 void ovl_check_protattr(struct inode *inode, struct dentry *upper); 888 int ovl_set_protattr(struct inode *inode, struct dentry *upper, 889 struct file_kattr *fa); 890 891 static inline void ovl_copyflags(struct inode *from, struct inode *to) 892 { 893 unsigned int mask = OVL_COPY_I_FLAGS_MASK; 894 895 inode_set_flags(to, from->i_flags & mask, mask); 896 } 897 898 /* dir.c */ 899 extern const struct inode_operations ovl_dir_inode_operations; 900 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir, 901 struct dentry *dentry, const struct qstr *name); 902 struct ovl_cattr { 903 dev_t rdev; 904 umode_t mode; 905 const char *link; 906 struct dentry *hardlink; 907 }; 908 909 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 910 911 struct dentry *ovl_create_real(struct ovl_fs *ofs, 912 struct dentry *parent, struct dentry *newdentry, 913 struct qstr *qname, 914 struct ovl_cattr *attr); 915 int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir, struct dentry *dentry); 916 #define OVL_TEMPNAME_SIZE 20 917 void ovl_tempname(char name[OVL_TEMPNAME_SIZE]); 918 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir, 919 struct ovl_cattr *attr); 920 921 /* file.c */ 922 extern const struct file_operations ovl_file_operations; 923 int ovl_real_fileattr_get(const struct path *realpath, struct file_kattr *fa); 924 int ovl_real_fileattr_set(const struct path *realpath, struct file_kattr *fa); 925 int ovl_fileattr_get(struct dentry *dentry, struct file_kattr *fa); 926 int ovl_fileattr_set(const struct mnt_idmap *idmap, 927 struct dentry *dentry, struct file_kattr *fa); 928 struct ovl_file; 929 struct ovl_file *ovl_file_alloc(struct file *realfile); 930 void ovl_file_free(struct ovl_file *of); 931 932 /* copy_up.c */ 933 int ovl_copy_up(struct dentry *dentry); 934 int ovl_copy_up_with_data(struct dentry *dentry); 935 int ovl_maybe_copy_up(struct dentry *dentry, int flags); 936 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new); 937 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat); 938 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct inode *realinode, 939 bool is_upper); 940 struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin); 941 int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh, 942 struct dentry *upper); 943 944 /* export.c */ 945 extern const struct export_operations ovl_export_operations; 946 extern const struct export_operations ovl_export_fid_operations; 947 948 /* super.c */ 949 int ovl_fill_super(struct super_block *sb, struct fs_context *fc); 950 951 /* Will this overlay be forced to mount/remount ro? */ 952 static inline bool ovl_force_readonly(struct ovl_fs *ofs) 953 { 954 return (!ovl_upper_mnt(ofs) || !ofs->workdir); 955 } 956 957 /* xattr.c */ 958 959 const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs); 960 int ovl_setattr(const struct mnt_idmap *idmap, struct dentry *dentry, 961 struct iattr *attr); 962 int ovl_getattr(const struct mnt_idmap *idmap, const struct path *path, 963 struct kstat *stat, u32 request_mask, unsigned int flags); 964 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 965