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 "ovl_entry.h" 11 12 #undef pr_fmt 13 #define pr_fmt(fmt) "overlayfs: " fmt 14 15 enum ovl_path_type { 16 __OVL_PATH_UPPER = (1 << 0), 17 __OVL_PATH_MERGE = (1 << 1), 18 __OVL_PATH_ORIGIN = (1 << 2), 19 }; 20 21 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 22 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 23 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 24 25 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay." 26 27 enum ovl_xattr { 28 OVL_XATTR_OPAQUE, 29 OVL_XATTR_REDIRECT, 30 OVL_XATTR_ORIGIN, 31 OVL_XATTR_IMPURE, 32 OVL_XATTR_NLINK, 33 OVL_XATTR_UPPER, 34 OVL_XATTR_METACOPY, 35 }; 36 37 enum ovl_inode_flag { 38 /* Pure upper dir that may contain non pure upper entries */ 39 OVL_IMPURE, 40 /* Non-merge dir that may contain whiteout entries */ 41 OVL_WHITEOUTS, 42 OVL_INDEX, 43 OVL_UPPERDATA, 44 /* Inode number will remain constant over copy up. */ 45 OVL_CONST_INO, 46 }; 47 48 enum ovl_entry_flag { 49 OVL_E_UPPER_ALIAS, 50 OVL_E_OPAQUE, 51 OVL_E_CONNECTED, 52 }; 53 54 enum { 55 OVL_XINO_OFF, 56 OVL_XINO_AUTO, 57 OVL_XINO_ON, 58 }; 59 60 /* 61 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 62 * where: 63 * origin.fh - exported file handle of the lower file 64 * origin.uuid - uuid of the lower filesystem 65 */ 66 #define OVL_FH_VERSION 0 67 #define OVL_FH_MAGIC 0xfb 68 69 /* CPU byte order required for fid decoding: */ 70 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 71 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 72 /* Is the real inode encoded in fid an upper inode? */ 73 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 74 75 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 76 OVL_FH_FLAG_PATH_UPPER) 77 78 #if defined(__LITTLE_ENDIAN) 79 #define OVL_FH_FLAG_CPU_ENDIAN 0 80 #elif defined(__BIG_ENDIAN) 81 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 82 #else 83 #error Endianness not defined 84 #endif 85 86 /* The type used to be returned by overlay exportfs for misaligned fid */ 87 #define OVL_FILEID_V0 0xfb 88 /* The type returned by overlay exportfs for 32bit aligned fid */ 89 #define OVL_FILEID_V1 0xf8 90 91 /* On-disk format for "origin" file handle */ 92 struct ovl_fb { 93 u8 version; /* 0 */ 94 u8 magic; /* 0xfb */ 95 u8 len; /* size of this header + size of fid */ 96 u8 flags; /* OVL_FH_FLAG_* */ 97 u8 type; /* fid_type of fid */ 98 uuid_t uuid; /* uuid of filesystem */ 99 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 100 } __packed; 101 102 /* In-memory and on-wire format for overlay file handle */ 103 struct ovl_fh { 104 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 105 union { 106 struct ovl_fb fb; 107 u8 buf[0]; 108 }; 109 } __packed; 110 111 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 112 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 113 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 114 offsetof(struct ovl_fb, fid)) 115 116 extern const char *ovl_xattr_table[]; 117 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 118 { 119 return ovl_xattr_table[ox]; 120 } 121 122 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 123 { 124 int err = vfs_rmdir(dir, dentry); 125 126 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 127 return err; 128 } 129 130 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 131 { 132 int err = vfs_unlink(dir, dentry, NULL); 133 134 pr_debug("unlink(%pd2) = %i\n", dentry, err); 135 return err; 136 } 137 138 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 139 struct dentry *new_dentry) 140 { 141 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 142 143 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 144 return err; 145 } 146 147 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 148 umode_t mode) 149 { 150 int err = vfs_create(dir, dentry, mode, true); 151 152 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 153 return err; 154 } 155 156 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 157 umode_t mode) 158 { 159 int err = vfs_mkdir(dir, dentry, mode); 160 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 161 return err; 162 } 163 164 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 165 umode_t mode, dev_t dev) 166 { 167 int err = vfs_mknod(dir, dentry, mode, dev); 168 169 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 170 return err; 171 } 172 173 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 174 const char *oldname) 175 { 176 int err = vfs_symlink(dir, dentry, oldname); 177 178 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 179 return err; 180 } 181 182 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry, 183 enum ovl_xattr ox, void *value, 184 size_t size) 185 { 186 const char *name = ovl_xattr(ofs, ox); 187 return vfs_getxattr(dentry, name, value, size); 188 } 189 190 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 191 enum ovl_xattr ox, const void *value, 192 size_t size) 193 { 194 const char *name = ovl_xattr(ofs, ox); 195 int err = vfs_setxattr(dentry, name, value, size, 0); 196 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 197 dentry, name, min((int)size, 48), value, size, err); 198 return err; 199 } 200 201 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 202 enum ovl_xattr ox) 203 { 204 const char *name = ovl_xattr(ofs, ox); 205 int err = vfs_removexattr(dentry, name); 206 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 207 return err; 208 } 209 210 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 211 struct inode *newdir, struct dentry *newdentry, 212 unsigned int flags) 213 { 214 int err; 215 216 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); 217 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 218 if (err) { 219 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 220 olddentry, newdentry, err); 221 } 222 return err; 223 } 224 225 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 226 { 227 int err = vfs_whiteout(dir, dentry); 228 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 229 return err; 230 } 231 232 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 233 { 234 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 235 int err = PTR_ERR_OR_ZERO(ret); 236 237 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 238 return ret; 239 } 240 241 static inline bool ovl_open_flags_need_copy_up(int flags) 242 { 243 if (!flags) 244 return false; 245 246 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 247 } 248 249 /* util.c */ 250 int ovl_want_write(struct dentry *dentry); 251 void ovl_drop_write(struct dentry *dentry); 252 struct dentry *ovl_workdir(struct dentry *dentry); 253 const struct cred *ovl_override_creds(struct super_block *sb); 254 int ovl_can_decode_fh(struct super_block *sb); 255 struct dentry *ovl_indexdir(struct super_block *sb); 256 bool ovl_index_all(struct super_block *sb); 257 bool ovl_verify_lower(struct super_block *sb); 258 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 259 bool ovl_dentry_remote(struct dentry *dentry); 260 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, 261 unsigned int mask); 262 bool ovl_dentry_weird(struct dentry *dentry); 263 enum ovl_path_type ovl_path_type(struct dentry *dentry); 264 void ovl_path_upper(struct dentry *dentry, struct path *path); 265 void ovl_path_lower(struct dentry *dentry, struct path *path); 266 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 267 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 268 struct dentry *ovl_dentry_upper(struct dentry *dentry); 269 struct dentry *ovl_dentry_lower(struct dentry *dentry); 270 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 271 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 272 struct dentry *ovl_dentry_real(struct dentry *dentry); 273 struct dentry *ovl_i_dentry_upper(struct inode *inode); 274 struct inode *ovl_inode_upper(struct inode *inode); 275 struct inode *ovl_inode_lower(struct inode *inode); 276 struct inode *ovl_inode_lowerdata(struct inode *inode); 277 struct inode *ovl_inode_real(struct inode *inode); 278 struct inode *ovl_inode_realdata(struct inode *inode); 279 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 280 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 281 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 282 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 283 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 284 bool ovl_dentry_is_opaque(struct dentry *dentry); 285 bool ovl_dentry_is_whiteout(struct dentry *dentry); 286 void ovl_dentry_set_opaque(struct dentry *dentry); 287 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 288 void ovl_dentry_set_upper_alias(struct dentry *dentry); 289 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 290 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 291 bool ovl_has_upperdata(struct inode *inode); 292 void ovl_set_upperdata(struct inode *inode); 293 bool ovl_redirect_dir(struct super_block *sb); 294 const char *ovl_dentry_get_redirect(struct dentry *dentry); 295 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 296 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 297 void ovl_dir_modified(struct dentry *dentry, bool impurity); 298 u64 ovl_dentry_version_get(struct dentry *dentry); 299 bool ovl_is_whiteout(struct dentry *dentry); 300 struct file *ovl_path_open(struct path *path, int flags); 301 int ovl_copy_up_start(struct dentry *dentry, int flags); 302 void ovl_copy_up_end(struct dentry *dentry); 303 bool ovl_already_copied_up(struct dentry *dentry, int flags); 304 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry); 305 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, 306 enum ovl_xattr ox); 307 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 308 enum ovl_xattr ox, const void *value, size_t size, 309 int xerr); 310 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 311 void ovl_set_flag(unsigned long flag, struct inode *inode); 312 void ovl_clear_flag(unsigned long flag, struct inode *inode); 313 bool ovl_test_flag(unsigned long flag, struct inode *inode); 314 bool ovl_inuse_trylock(struct dentry *dentry); 315 void ovl_inuse_unlock(struct dentry *dentry); 316 bool ovl_is_inuse(struct dentry *dentry); 317 bool ovl_need_index(struct dentry *dentry); 318 int ovl_nlink_start(struct dentry *dentry); 319 void ovl_nlink_end(struct dentry *dentry); 320 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 321 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry); 322 bool ovl_is_metacopy_dentry(struct dentry *dentry); 323 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, 324 int padding); 325 326 static inline bool ovl_is_impuredir(struct super_block *sb, 327 struct dentry *dentry) 328 { 329 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE); 330 } 331 332 /* 333 * With xino=auto, we do best effort to keep all inodes on same st_dev and 334 * d_ino consistent with st_ino. 335 * With xino=on, we do the same effort but we warn if we failed. 336 */ 337 static inline bool ovl_xino_warn(struct super_block *sb) 338 { 339 return OVL_FS(sb)->config.xino == OVL_XINO_ON; 340 } 341 342 /* All layers on same fs? */ 343 static inline bool ovl_same_fs(struct super_block *sb) 344 { 345 return OVL_FS(sb)->xino_mode == 0; 346 } 347 348 /* All overlay inodes have same st_dev? */ 349 static inline bool ovl_same_dev(struct super_block *sb) 350 { 351 return OVL_FS(sb)->xino_mode >= 0; 352 } 353 354 static inline unsigned int ovl_xino_bits(struct super_block *sb) 355 { 356 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0; 357 } 358 359 static inline void ovl_inode_lock(struct inode *inode) 360 { 361 mutex_lock(&OVL_I(inode)->lock); 362 } 363 364 static inline int ovl_inode_lock_interruptible(struct inode *inode) 365 { 366 return mutex_lock_interruptible(&OVL_I(inode)->lock); 367 } 368 369 static inline void ovl_inode_unlock(struct inode *inode) 370 { 371 mutex_unlock(&OVL_I(inode)->lock); 372 } 373 374 375 /* namei.c */ 376 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 377 378 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 379 { 380 if (fh_len < sizeof(struct ovl_fh)) 381 return -EINVAL; 382 383 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 384 } 385 386 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, 387 bool connected); 388 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 389 struct dentry *upperdentry, struct ovl_path **stackp); 390 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 391 enum ovl_xattr ox, struct dentry *real, bool is_upper, 392 bool set); 393 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 394 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 395 int ovl_get_index_name(struct dentry *origin, struct qstr *name); 396 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 397 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 398 struct dentry *origin, bool verify); 399 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 400 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 401 unsigned int flags); 402 bool ovl_lower_positive(struct dentry *dentry); 403 404 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 405 struct dentry *origin, bool set) 406 { 407 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, 408 false, set); 409 } 410 411 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 412 struct dentry *upper, bool set) 413 { 414 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); 415 } 416 417 /* readdir.c */ 418 extern const struct file_operations ovl_dir_operations; 419 struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 420 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 421 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 422 void ovl_cache_free(struct list_head *list); 423 void ovl_dir_cache_free(struct inode *inode); 424 int ovl_check_d_type_supported(struct path *realpath); 425 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 426 struct dentry *dentry, int level); 427 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 428 429 /* inode.c */ 430 int ovl_set_nlink_upper(struct dentry *dentry); 431 int ovl_set_nlink_lower(struct dentry *dentry); 432 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 433 struct dentry *upperdentry, 434 unsigned int fallback); 435 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 436 int ovl_getattr(const struct path *path, struct kstat *stat, 437 u32 request_mask, unsigned int flags); 438 int ovl_permission(struct inode *inode, int mask); 439 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 440 const void *value, size_t size, int flags); 441 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 442 void *value, size_t size); 443 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 444 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 445 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); 446 bool ovl_is_private_xattr(struct super_block *sb, const char *name); 447 448 struct ovl_inode_params { 449 struct inode *newinode; 450 struct dentry *upperdentry; 451 struct ovl_path *lowerpath; 452 bool index; 453 unsigned int numlower; 454 char *redirect; 455 struct dentry *lowerdata; 456 }; 457 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 458 unsigned long ino, int fsid); 459 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 460 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 461 bool is_upper); 462 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 463 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 464 struct inode *ovl_get_inode(struct super_block *sb, 465 struct ovl_inode_params *oip); 466 static inline void ovl_copyattr(struct inode *from, struct inode *to) 467 { 468 to->i_uid = from->i_uid; 469 to->i_gid = from->i_gid; 470 to->i_mode = from->i_mode; 471 to->i_atime = from->i_atime; 472 to->i_mtime = from->i_mtime; 473 to->i_ctime = from->i_ctime; 474 i_size_write(to, i_size_read(from)); 475 } 476 477 static inline void ovl_copyflags(struct inode *from, struct inode *to) 478 { 479 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; 480 481 inode_set_flags(to, from->i_flags & mask, mask); 482 } 483 484 /* dir.c */ 485 extern const struct inode_operations ovl_dir_inode_operations; 486 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, 487 struct dentry *dentry); 488 struct ovl_cattr { 489 dev_t rdev; 490 umode_t mode; 491 const char *link; 492 struct dentry *hardlink; 493 }; 494 495 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 496 497 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, 498 struct ovl_cattr *attr); 499 int ovl_cleanup(struct inode *dir, struct dentry *dentry); 500 struct dentry *ovl_lookup_temp(struct dentry *workdir); 501 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); 502 503 /* file.c */ 504 extern const struct file_operations ovl_file_operations; 505 int __init ovl_aio_request_cache_init(void); 506 void ovl_aio_request_cache_destroy(void); 507 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 508 long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 509 510 /* copy_up.c */ 511 int ovl_copy_up(struct dentry *dentry); 512 int ovl_copy_up_with_data(struct dentry *dentry); 513 int ovl_maybe_copy_up(struct dentry *dentry, int flags); 514 int ovl_copy_xattr(struct super_block *sb, struct dentry *old, 515 struct dentry *new); 516 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 517 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); 518 int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 519 struct dentry *upper); 520 521 /* export.c */ 522 extern const struct export_operations ovl_export_operations; 523