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