/* SPDX-License-Identifier: GPL-2.0-only */ /* * * Copyright (C) 2011 Novell Inc. */ #include #include #include #include "ovl_entry.h" #undef pr_fmt #define pr_fmt(fmt) "overlayfs: " fmt enum ovl_path_type { __OVL_PATH_UPPER = (1 << 0), __OVL_PATH_MERGE = (1 << 1), __OVL_PATH_ORIGIN = (1 << 2), }; #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) #define OVL_XATTR_NAMESPACE "overlay." #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE enum ovl_xattr { OVL_XATTR_OPAQUE, OVL_XATTR_REDIRECT, OVL_XATTR_ORIGIN, OVL_XATTR_IMPURE, OVL_XATTR_NLINK, OVL_XATTR_UPPER, OVL_XATTR_METACOPY, OVL_XATTR_PROTATTR, }; enum ovl_inode_flag { /* Pure upper dir that may contain non pure upper entries */ OVL_IMPURE, /* Non-merge dir that may contain whiteout entries */ OVL_WHITEOUTS, OVL_INDEX, OVL_UPPERDATA, /* Inode number will remain constant over copy up. */ OVL_CONST_INO, }; enum ovl_entry_flag { OVL_E_UPPER_ALIAS, OVL_E_OPAQUE, OVL_E_CONNECTED, }; enum { OVL_XINO_OFF, OVL_XINO_AUTO, OVL_XINO_ON, }; /* * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, * where: * origin.fh - exported file handle of the lower file * origin.uuid - uuid of the lower filesystem */ #define OVL_FH_VERSION 0 #define OVL_FH_MAGIC 0xfb /* CPU byte order required for fid decoding: */ #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) /* Is the real inode encoded in fid an upper inode? */ #define OVL_FH_FLAG_PATH_UPPER (1 << 2) #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ OVL_FH_FLAG_PATH_UPPER) #if defined(__LITTLE_ENDIAN) #define OVL_FH_FLAG_CPU_ENDIAN 0 #elif defined(__BIG_ENDIAN) #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN #else #error Endianness not defined #endif /* The type used to be returned by overlay exportfs for misaligned fid */ #define OVL_FILEID_V0 0xfb /* The type returned by overlay exportfs for 32bit aligned fid */ #define OVL_FILEID_V1 0xf8 /* On-disk format for "origin" file handle */ struct ovl_fb { u8 version; /* 0 */ u8 magic; /* 0xfb */ u8 len; /* size of this header + size of fid */ u8 flags; /* OVL_FH_FLAG_* */ u8 type; /* fid_type of fid */ uuid_t uuid; /* uuid of filesystem */ u32 fid[]; /* file identifier should be 32bit aligned in-memory */ } __packed; /* In-memory and on-wire format for overlay file handle */ struct ovl_fh { u8 padding[3]; /* make sure fb.fid is 32bit aligned */ union { struct ovl_fb fb; DECLARE_FLEX_ARRAY(u8, buf); }; } __packed; #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ offsetof(struct ovl_fb, fid)) extern const char *const ovl_xattr_table[][2]; static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) { return ovl_xattr_table[ox][ofs->config.userxattr]; } static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) { int err = vfs_rmdir(&init_user_ns, dir, dentry); pr_debug("rmdir(%pd2) = %i\n", dentry, err); return err; } static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) { int err = vfs_unlink(&init_user_ns, dir, dentry, NULL); pr_debug("unlink(%pd2) = %i\n", dentry, err); return err; } static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) { int err = vfs_link(old_dentry, &init_user_ns, dir, new_dentry, NULL); pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); return err; } static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, umode_t mode) { int err = vfs_create(&init_user_ns, dir, dentry, mode, true); pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); return err; } static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int err = vfs_mkdir(&init_user_ns, dir, dentry, mode); pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); return err; } static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { int err = vfs_mknod(&init_user_ns, dir, dentry, mode, dev); pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); return err; } static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) { int err = vfs_symlink(&init_user_ns, dir, dentry, oldname); pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); return err; } static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry, enum ovl_xattr ox, void *value, size_t size) { const char *name = ovl_xattr(ofs, ox); int err = vfs_getxattr(&init_user_ns, dentry, name, value, size); int len = (value && err > 0) ? err : 0; pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", dentry, name, min(len, 48), value, size, err); return err; } static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, enum ovl_xattr ox, const void *value, size_t size) { const char *name = ovl_xattr(ofs, ox); int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, 0); pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", dentry, name, min((int)size, 48), value, size, err); return err; } static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, enum ovl_xattr ox) { const char *name = ovl_xattr(ofs, ox); int err = vfs_removexattr(&init_user_ns, dentry, name); pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); return err; } static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, struct inode *newdir, struct dentry *newdentry, unsigned int flags) { int err; struct renamedata rd = { .old_mnt_userns = &init_user_ns, .old_dir = olddir, .old_dentry = olddentry, .new_mnt_userns = &init_user_ns, .new_dir = newdir, .new_dentry = newdentry, .flags = flags, }; pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); err = vfs_rename(&rd); if (err) { pr_debug("...rename(%pd2, %pd2, ...) = %i\n", olddentry, newdentry, err); } return err; } static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) { int err = vfs_whiteout(&init_user_ns, dir, dentry); pr_debug("whiteout(%pd2) = %i\n", dentry, err); return err; } static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) { struct dentry *ret = vfs_tmpfile(&init_user_ns, dentry, mode, 0); int err = PTR_ERR_OR_ZERO(ret); pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); return ret; } static inline bool ovl_open_flags_need_copy_up(int flags) { if (!flags) return false; return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); } static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs) { /* * To avoid regressions in existing setups with overlay lower offline * changes, we allow lower changes only if none of the new features * are used. */ return (!ofs->config.index && !ofs->config.metacopy && !ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON); } /* util.c */ int ovl_want_write(struct dentry *dentry); void ovl_drop_write(struct dentry *dentry); struct dentry *ovl_workdir(struct dentry *dentry); const struct cred *ovl_override_creds(struct super_block *sb); int ovl_can_decode_fh(struct super_block *sb); struct dentry *ovl_indexdir(struct super_block *sb); bool ovl_index_all(struct super_block *sb); bool ovl_verify_lower(struct super_block *sb); struct ovl_entry *ovl_alloc_entry(unsigned int numlower); bool ovl_dentry_remote(struct dentry *dentry); void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry); void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, unsigned int mask); bool ovl_dentry_weird(struct dentry *dentry); enum ovl_path_type ovl_path_type(struct dentry *dentry); void ovl_path_upper(struct dentry *dentry, struct path *path); void ovl_path_lower(struct dentry *dentry, struct path *path); void ovl_path_lowerdata(struct dentry *dentry, struct path *path); void ovl_i_path_real(struct inode *inode, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); const struct ovl_layer *ovl_i_layer_lower(struct inode *inode); const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); struct dentry *ovl_i_dentry_upper(struct inode *inode); struct inode *ovl_inode_upper(struct inode *inode); struct inode *ovl_inode_lower(struct inode *inode); struct inode *ovl_inode_lowerdata(struct inode *inode); struct inode *ovl_inode_real(struct inode *inode); struct inode *ovl_inode_realdata(struct inode *inode); struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); bool ovl_dentry_is_opaque(struct dentry *dentry); bool ovl_dentry_is_whiteout(struct dentry *dentry); void ovl_dentry_set_opaque(struct dentry *dentry); bool ovl_dentry_has_upper_alias(struct dentry *dentry); void ovl_dentry_set_upper_alias(struct dentry *dentry); bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); bool ovl_has_upperdata(struct inode *inode); void ovl_set_upperdata(struct inode *inode); bool ovl_redirect_dir(struct super_block *sb); const char *ovl_dentry_get_redirect(struct dentry *dentry); void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); void ovl_dir_modified(struct dentry *dentry, bool impurity); u64 ovl_dentry_version_get(struct dentry *dentry); bool ovl_is_whiteout(struct dentry *dentry); struct file *ovl_path_open(struct path *path, int flags); int ovl_copy_up_start(struct dentry *dentry, int flags); void ovl_copy_up_end(struct dentry *dentry); bool ovl_already_copied_up(struct dentry *dentry, int flags); bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry); bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, enum ovl_xattr ox); int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, enum ovl_xattr ox, const void *value, size_t size, int xerr); int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); bool ovl_inuse_trylock(struct dentry *dentry); void ovl_inuse_unlock(struct dentry *dentry); bool ovl_is_inuse(struct dentry *dentry); bool ovl_need_index(struct dentry *dentry); int ovl_nlink_start(struct dentry *dentry); void ovl_nlink_end(struct dentry *dentry); int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry); bool ovl_is_metacopy_dentry(struct dentry *dentry); char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, int padding); int ovl_sync_status(struct ovl_fs *ofs); static inline void ovl_set_flag(unsigned long flag, struct inode *inode) { set_bit(flag, &OVL_I(inode)->flags); } static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) { clear_bit(flag, &OVL_I(inode)->flags); } static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) { return test_bit(flag, &OVL_I(inode)->flags); } static inline bool ovl_is_impuredir(struct super_block *sb, struct dentry *dentry) { return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE); } /* * With xino=auto, we do best effort to keep all inodes on same st_dev and * d_ino consistent with st_ino. * With xino=on, we do the same effort but we warn if we failed. */ static inline bool ovl_xino_warn(struct super_block *sb) { return OVL_FS(sb)->config.xino == OVL_XINO_ON; } /* All layers on same fs? */ static inline bool ovl_same_fs(struct super_block *sb) { return OVL_FS(sb)->xino_mode == 0; } /* All overlay inodes have same st_dev? */ static inline bool ovl_same_dev(struct super_block *sb) { return OVL_FS(sb)->xino_mode >= 0; } static inline unsigned int ovl_xino_bits(struct super_block *sb) { return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0; } static inline void ovl_inode_lock(struct inode *inode) { mutex_lock(&OVL_I(inode)->lock); } static inline int ovl_inode_lock_interruptible(struct inode *inode) { return mutex_lock_interruptible(&OVL_I(inode)->lock); } static inline void ovl_inode_unlock(struct inode *inode) { mutex_unlock(&OVL_I(inode)->lock); } /* namei.c */ int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) { if (fh_len < sizeof(struct ovl_fh)) return -EINVAL; return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); } struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, struct vfsmount *mnt, bool connected); int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, struct dentry *upperdentry, struct ovl_path **stackp); int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, enum ovl_xattr ox, struct dentry *real, bool is_upper, bool set); struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, struct qstr *name); struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, struct dentry *origin, bool verify); int ovl_path_next(int idx, struct dentry *dentry, struct path *path); struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); bool ovl_lower_positive(struct dentry *dentry); static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, struct dentry *origin, bool set) { return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, false, set); } static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, struct dentry *upper, bool set) { return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); } /* readdir.c */ extern const struct file_operations ovl_dir_operations; struct file *ovl_dir_real_file(const struct file *file, bool want_upper); int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); void ovl_cache_free(struct list_head *list); void ovl_dir_cache_free(struct inode *inode); int ovl_check_d_type_supported(struct path *realpath); int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, struct dentry *dentry, int level); int ovl_indexdir_cleanup(struct ovl_fs *ofs); /* * Can we iterate real dir directly? * * Non-merge dir may contain whiteouts from a time it was a merge upper, before * lower dir was removed under it and possibly before it was rotated from upper * to lower layer. */ static inline bool ovl_dir_is_real(struct dentry *dir) { return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir)); } /* inode.c */ int ovl_set_nlink_upper(struct dentry *dentry); int ovl_set_nlink_lower(struct dentry *dentry); unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, struct dentry *upperdentry, unsigned int fallback); int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, struct iattr *attr); int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path, struct kstat *stat, u32 request_mask, unsigned int flags); int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode, int mask); int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags); int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, void *value, size_t size); ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu); int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); bool ovl_is_private_xattr(struct super_block *sb, const char *name); struct ovl_inode_params { struct inode *newinode; struct dentry *upperdentry; struct ovl_path *lowerpath; bool index; unsigned int numlower; char *redirect; struct dentry *lowerdata; }; void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, unsigned long ino, int fsid); struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, bool is_upper); bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); struct inode *ovl_get_inode(struct super_block *sb, struct ovl_inode_params *oip); void ovl_copyattr(struct inode *to); /* vfs inode flags copied from real to ovl inode */ #define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE) /* vfs inode flags read from overlay.protattr xattr to ovl inode */ #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE) /* * fileattr flags copied from lower to upper inode on copy up. * We cannot copy up immutable/append-only flags, because that would prevent * linking temp inode to upper dir, so we store them in xattr instead. */ #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL) #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME) #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL) #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE) void ovl_check_protattr(struct inode *inode, struct dentry *upper); int ovl_set_protattr(struct inode *inode, struct dentry *upper, struct fileattr *fa); static inline void ovl_copyflags(struct inode *from, struct inode *to) { unsigned int mask = OVL_COPY_I_FLAGS_MASK; inode_set_flags(to, from->i_flags & mask, mask); } /* dir.c */ extern const struct inode_operations ovl_dir_inode_operations; int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry); struct ovl_cattr { dev_t rdev; umode_t mode; const char *link; struct dentry *hardlink; }; #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode); struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, struct ovl_cattr *attr); int ovl_cleanup(struct inode *dir, struct dentry *dentry); struct dentry *ovl_lookup_temp(struct dentry *workdir); struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); /* file.c */ extern const struct file_operations ovl_file_operations; int __init ovl_aio_request_cache_init(void); void ovl_aio_request_cache_destroy(void); int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa); int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa); int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa); int ovl_fileattr_set(struct user_namespace *mnt_userns, struct dentry *dentry, struct fileattr *fa); /* copy_up.c */ int ovl_copy_up(struct dentry *dentry); int ovl_copy_up_with_data(struct dentry *dentry); int ovl_maybe_copy_up(struct dentry *dentry, int flags); int ovl_copy_xattr(struct super_block *sb, struct dentry *old, struct dentry *new); int ovl_set_attr(struct dentry *upper, struct kstat *stat); struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, bool is_upper); int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower, struct dentry *upper); /* export.c */ extern const struct export_operations ovl_export_operations;