diff options
| -rw-r--r-- | fs/overlayfs/copy_up.c | 1 | ||||
| -rw-r--r-- | fs/overlayfs/dir.c | 226 | ||||
| -rw-r--r-- | fs/overlayfs/inode.c | 246 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 30 | ||||
| -rw-r--r-- | fs/overlayfs/super.c | 178 |
5 files changed, 445 insertions, 236 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 80aa6f1eb336..54e5d6681786 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -292,6 +292,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, goto out_cleanup; ovl_dentry_update(dentry, newdentry); + ovl_inode_update(d_inode(dentry), d_inode(newdentry)); newdentry = NULL; /* diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 5c9d2d80ff70..12bcd07b9e32 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -138,9 +138,12 @@ static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, int err; enum ovl_path_type type; struct path realpath; + const struct cred *old_cred; type = ovl_path_real(dentry, &realpath); + old_cred = ovl_override_creds(dentry->d_sb); err = vfs_getattr(&realpath, stat); + revert_creds(old_cred); if (err) return err; @@ -158,6 +161,22 @@ static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, return 0; } +/* Common operations required to be done after creation of file on upper */ +static void ovl_instantiate(struct dentry *dentry, struct inode *inode, + struct dentry *newdentry, bool hardlink) +{ + ovl_dentry_version_inc(dentry->d_parent); + ovl_dentry_update(dentry, newdentry); + if (!hardlink) { + ovl_inode_update(inode, d_inode(newdentry)); + ovl_copyattr(newdentry->d_inode, inode); + } else { + WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); + inc_nlink(inode); + } + d_instantiate(dentry, inode); +} + static int ovl_create_upper(struct dentry *dentry, struct inode *inode, struct kstat *stat, const char *link, struct dentry *hardlink) @@ -177,10 +196,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode, if (err) goto out_dput; - ovl_dentry_version_inc(dentry->d_parent); - ovl_dentry_update(dentry, newdentry); - ovl_copyattr(newdentry->d_inode, inode); - d_instantiate(dentry, inode); + ovl_instantiate(dentry, inode, newdentry, !!hardlink); newdentry = NULL; out_dput: dput(newdentry); @@ -291,23 +307,29 @@ static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) { int err; struct dentry *ret = NULL; + enum ovl_path_type type = ovl_path_type(dentry); LIST_HEAD(list); err = ovl_check_empty_dir(dentry, &list); - if (err) + if (err) { ret = ERR_PTR(err); - else { - /* - * If no upperdentry then skip clearing whiteouts. - * - * Can race with copy-up, since we don't hold the upperdir - * mutex. Doesn't matter, since copy-up can't create a - * non-empty directory from an empty one. - */ - if (ovl_dentry_upper(dentry)) - ret = ovl_clear_empty(dentry, &list); + goto out_free; } + /* + * When removing an empty opaque directory, then it makes no sense to + * replace it with an exact replica of itself. + * + * If no upperdentry then skip clearing whiteouts. + * + * Can race with copy-up, since we don't hold the upperdir mutex. + * Doesn't matter, since copy-up can't create a non-empty directory + * from an empty one. + */ + if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type)) + ret = ovl_clear_empty(dentry, &list); + +out_free: ovl_cache_free(&list); return ret; @@ -347,7 +369,23 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, if (err) goto out_dput2; - if (S_ISDIR(stat->mode)) { + /* + * mode could have been mutilated due to umask (e.g. sgid directory) + */ + if (!hardlink && + !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { + struct iattr attr = { + .ia_valid = ATTR_MODE, + .ia_mode = stat->mode, + }; + inode_lock(newdentry->d_inode); + err = notify_change(newdentry, &attr, NULL); + inode_unlock(newdentry->d_inode); + if (err) + goto out_cleanup; + } + + if (!hardlink && S_ISDIR(stat->mode)) { err = ovl_set_opaque(newdentry); if (err) goto out_cleanup; @@ -363,10 +401,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, if (err) goto out_cleanup; } - ovl_dentry_version_inc(dentry->d_parent); - ovl_dentry_update(dentry, newdentry); - ovl_copyattr(newdentry->d_inode, inode); - d_instantiate(dentry, inode); + ovl_instantiate(dentry, inode, newdentry, !!hardlink); newdentry = NULL; out_dput2: dput(upper); @@ -382,52 +417,42 @@ out_cleanup: goto out_dput2; } -static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, - const char *link, struct dentry *hardlink) +static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, + struct kstat *stat, const char *link, + struct dentry *hardlink) { int err; - struct inode *inode; - struct kstat stat = { - .mode = mode, - .rdev = rdev, - }; - - err = -ENOMEM; - inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); - if (!inode) - goto out; + const struct cred *old_cred; + struct cred *override_cred; err = ovl_copy_up(dentry->d_parent); if (err) - goto out_iput; - - if (!ovl_dentry_is_opaque(dentry)) { - err = ovl_create_upper(dentry, inode, &stat, link, hardlink); - } else { - const struct cred *old_cred; - struct cred *override_cred; - - old_cred = ovl_override_creds(dentry->d_sb); - - err = -ENOMEM; - override_cred = prepare_creds(); - if (override_cred) { - override_cred->fsuid = old_cred->fsuid; - override_cred->fsgid = old_cred->fsgid; - put_cred(override_creds(override_cred)); - put_cred(override_cred); + return err; - err = ovl_create_over_whiteout(dentry, inode, &stat, - link, hardlink); - } - revert_creds(old_cred); + old_cred = ovl_override_creds(dentry->d_sb); + err = -ENOMEM; + override_cred = prepare_creds(); + if (override_cred) { + override_cred->fsuid = inode->i_uid; + override_cred->fsgid = inode->i_gid; + put_cred(override_creds(override_cred)); + put_cred(override_cred); + + if (!ovl_dentry_is_opaque(dentry)) + err = ovl_create_upper(dentry, inode, stat, link, + hardlink); + else + err = ovl_create_over_whiteout(dentry, inode, stat, + link, hardlink); } + revert_creds(old_cred); + if (!err) { + struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); - if (!err) - inode = NULL; -out_iput: - iput(inode); -out: + WARN_ON(inode->i_mode != realinode->i_mode); + WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); + WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); + } return err; } @@ -435,13 +460,30 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, const char *link) { int err; + struct inode *inode; + struct kstat stat = { + .rdev = rdev, + }; err = ovl_want_write(dentry); - if (!err) { - err = ovl_create_or_link(dentry, mode, rdev, link, NULL); - ovl_drop_write(dentry); - } + if (err) + goto out; + + err = -ENOMEM; + inode = ovl_new_inode(dentry->d_sb, mode); + if (!inode) + goto out_drop_write; + + inode_init_owner(inode, dentry->d_parent->d_inode, mode); + stat.mode = inode->i_mode; + err = ovl_create_or_link(dentry, inode, &stat, link, NULL); + if (err) + iput(inode); + +out_drop_write: + ovl_drop_write(dentry); +out: return err; } @@ -476,7 +518,7 @@ static int ovl_link(struct dentry *old, struct inode *newdir, struct dentry *new) { int err; - struct dentry *upper; + struct inode *inode; err = ovl_want_write(old); if (err) @@ -486,8 +528,12 @@ static int ovl_link(struct dentry *old, struct inode *newdir, if (err) goto out_drop_write; - upper = ovl_dentry_upper(old); - err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); + inode = d_inode(old); + ihold(inode); + + err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old)); + if (err) + iput(inode); out_drop_write: ovl_drop_write(old); @@ -511,24 +557,10 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) return -EROFS; if (is_dir) { - if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { - opaquedir = ovl_check_empty_and_clear(dentry); - err = PTR_ERR(opaquedir); - if (IS_ERR(opaquedir)) - goto out; - } else { - LIST_HEAD(list); - - /* - * When removing an empty opaque directory, then it - * makes no sense to replace it with an exact replica of - * itself. But emptiness still needs to be checked. - */ - err = ovl_check_empty_dir(dentry, &list); - ovl_cache_free(&list); - if (err) - goto out; - } + opaquedir = ovl_check_empty_and_clear(dentry); + err = PTR_ERR(opaquedir); + if (IS_ERR(opaquedir)) + goto out; } err = ovl_lock_rename_workdir(workdir, upperdir); @@ -633,6 +665,8 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) { enum ovl_path_type type; int err; + const struct cred *old_cred; + err = ovl_check_sticky(dentry); if (err) @@ -647,14 +681,18 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) goto out_drop_write; type = ovl_path_type(dentry); - if (OVL_TYPE_PURE_UPPER(type)) { - err = ovl_remove_upper(dentry, is_dir); - } else { - const struct cred *old_cred = ovl_override_creds(dentry->d_sb); + old_cred = ovl_override_creds(dentry->d_sb); + if (OVL_TYPE_PURE_UPPER(type)) + err = ovl_remove_upper(dentry, is_dir); + else err = ovl_remove_and_whiteout(dentry, is_dir); - - revert_creds(old_cred); + revert_creds(old_cred); + if (!err) { + if (is_dir) + clear_nlink(dentry->d_inode); + else + drop_nlink(dentry->d_inode); } out_drop_write: ovl_drop_write(dentry); @@ -760,8 +798,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, old_opaque = !OVL_TYPE_PURE_UPPER(old_type); new_opaque = !OVL_TYPE_PURE_UPPER(new_type); - if (old_opaque || new_opaque) - old_cred = ovl_override_creds(old->d_sb); + old_cred = ovl_override_creds(old->d_sb); if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { opaquedir = ovl_check_empty_and_clear(new); @@ -891,8 +928,7 @@ out_dput_old: out_unlock: unlock_rename(new_upperdir, old_upperdir); out_revert_creds: - if (old_opaque || new_opaque) - revert_creds(old_cred); + revert_creds(old_cred); out_drop_write: ovl_drop_write(old); out: @@ -913,8 +949,10 @@ const struct inode_operations ovl_dir_inode_operations = { .mknod = ovl_mknod, .permission = ovl_permission, .getattr = ovl_dir_getattr, - .setxattr = ovl_setxattr, + .setxattr = generic_setxattr, .getxattr = ovl_getxattr, .listxattr = ovl_listxattr, .removexattr = ovl_removexattr, + .get_acl = ovl_get_acl, + .update_time = ovl_update_time, }; diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index d554e86abbe3..1b885c156028 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -41,6 +41,7 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) { int err; struct dentry *upperdentry; + const struct cred *old_cred; /* * Check for permissions before trying to copy-up. This is redundant @@ -84,7 +85,9 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) attr->ia_valid &= ~ATTR_MODE; inode_lock(upperdentry->d_inode); + old_cred = ovl_override_creds(dentry->d_sb); err = notify_change(upperdentry, attr, NULL); + revert_creds(old_cred); if (!err) ovl_copyattr(upperdentry->d_inode, dentry->d_inode); inode_unlock(upperdentry->d_inode); @@ -102,96 +105,46 @@ static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct path realpath; + const struct cred *old_cred; + int err; ovl_path_real(dentry, &realpath); - return vfs_getattr(&realpath, stat); + old_cred = ovl_override_creds(dentry->d_sb); + err = vfs_getattr(&realpath, stat); + revert_creds(old_cred); + return err; } int ovl_permission(struct inode *inode, int mask) { - struct ovl_entry *oe; - struct dentry *alias = NULL; - struct inode *realinode; - struct dentry *realdentry; bool is_upper; + struct inode *realinode = ovl_inode_real(inode, &is_upper); + const struct cred *old_cred; int err; - if (S_ISDIR(inode->i_mode)) { - oe = inode->i_private; - } else if (mask & MAY_NOT_BLOCK) { - return -ECHILD; - } else { - /* - * For non-directories find an alias and get the info - * from there. - */ - alias = d_find_any_alias(inode); - if (WARN_ON(!alias)) - return -ENOENT; - - oe = alias->d_fsdata; - } - - realdentry = ovl_entry_real(oe, &is_upper); - - if (ovl_is_default_permissions(inode)) { - struct kstat stat; - struct path realpath = { .dentry = realdentry }; - - if (mask & MAY_NOT_BLOCK) - return -ECHILD; - - realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper); - - err = vfs_getattr(&realpath, &stat); - if (err) - goto out_dput; - - err = -ESTALE; - if ((stat.mode ^ inode->i_mode) & S_IFMT) - goto out_dput; - - inode->i_mode = stat.mode; - inode->i_uid = stat.uid; - inode->i_gid = stat.gid; - - err = generic_permission(inode, mask); - goto out_dput; - } - /* Careful in RCU walk mode */ - realinode = ACCESS_ONCE(realdentry->d_inode); if (!realinode) { WARN_ON(!(mask & MAY_NOT_BLOCK)); - err = -ENOENT; - goto out_dput; + return -ECHILD; } - if (mask & MAY_WRITE) { - umode_t mode = realinode->i_mode; - - /* - * Writes will always be redirected to upper layer, so - * ignore lower layer being read-only. - * - * If the overlay itself is read-only then proceed - * with the permission check, don't return EROFS. - * This will only happen if this is the lower layer of - * another overlayfs. - * - * If upper fs becomes read-only after the overlay was - * constructed return EROFS to prevent modification of - * upper layer. - */ - err = -EROFS; - if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) && - (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) - goto out_dput; + /* + * Check overlay inode with the creds of task and underlying inode + * with creds of mounter + */ + err = generic_permission(inode, mask); + if (err) + return err; + + old_cred = ovl_override_creds(inode->i_sb); + if (!is_upper && !special_file(realinode->i_mode) && mask & MAY_WRITE) { + mask &= ~(MAY_WRITE | MAY_APPEND); + /* Make sure mounter can read file for copy up later */ + mask |= MAY_READ; } + err = inode_permission(realinode, mask); + revert_creds(old_cred); - err = __inode_permission(realinode, mask); -out_dput: - dput(alias); return err; } @@ -201,6 +154,8 @@ static const char *ovl_get_link(struct dentry *dentry, { struct dentry *realdentry; struct inode *realinode; + const struct cred *old_cred; + const char *p; if (!dentry) return ERR_PTR(-ECHILD); @@ -211,13 +166,18 @@ static const char *ovl_get_link(struct dentry *dentry, if (WARN_ON(!realinode->i_op->get_link)) return ERR_PTR(-EPERM); - return realinode->i_op->get_link(realdentry, realinode, done); + old_cred = ovl_override_creds(dentry->d_sb); + p = realinode->i_op->get_link(realdentry, realinode, done); + revert_creds(old_cred); + return p; } static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz) { struct path realpath; struct inode *realinode; + const struct cred *old_cred; + int err; ovl_path_real(dentry, &realpath); realinode = realpath.dentry->d_inode; @@ -225,15 +185,17 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz) if (!realinode->i_op->readlink) return -EINVAL; - touch_atime(&realpath); - - return realinode->i_op->readlink(realpath.dentry, buf, bufsiz); + old_cred = ovl_override_creds(dentry->d_sb); + err = realinode->i_op->readlink(realpath.dentry, buf, bufsiz); + revert_creds(old_cred); + return err; } - static bool ovl_is_private_xattr(const char *name) { - return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0; +#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "." + return strncmp(name, OVL_XATTR_PRE_NAME, + sizeof(OVL_XATTR_PRE_NAME) - 1) == 0; } int ovl_setxattr(struct dentry *dentry, struct inode *inode, @@ -242,21 +204,20 @@ int ovl_setxattr(struct dentry *dentry, struct inode *inode, { int err; struct dentry *upperdentry; + const struct cred *old_cred; err = ovl_want_write(dentry); if (err) goto out; - err = -EPERM; - if (ovl_is_private_xattr(name)) - goto out_drop_write; - err = ovl_copy_up(dentry); if (err) goto out_drop_write; upperdentry = ovl_dentry_upper(dentry); + old_cred = ovl_override_creds(dentry->d_sb); err = vfs_setxattr(upperdentry, name, value, size, flags); + revert_creds(old_cred); out_drop_write: ovl_drop_write(dentry); @@ -268,11 +229,16 @@ ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *value, size_t size) { struct dentry *realdentry = ovl_dentry_real(dentry); + ssize_t res; + const struct cred *old_cred; if (ovl_is_private_xattr(name)) return -ENODATA; - return vfs_getxattr(realdentry, name, value, size); + old_cred = ovl_override_creds(dentry->d_sb); + res = vfs_getxattr(realdentry, name, value, size); + revert_creds(old_cred); + return res; } ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) @@ -280,8 +246,11 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) struct dentry *realdentry = ovl_dentry_real(dentry); ssize_t res; int off; + const struct cred *old_cred; + old_cred = ovl_override_creds(dentry->d_sb); res = vfs_listxattr(realdentry, list, size); + revert_creds(old_cred); if (res <= 0 || size == 0) return res; @@ -308,6 +277,7 @@ int ovl_removexattr(struct dentry *dentry, const char *name) int err; struct path realpath; enum ovl_path_type type = ovl_path_real(dentry, &realpath); + const struct cred *old_cred; err = ovl_want_write(dentry); if (err) @@ -329,13 +299,34 @@ int ovl_removexattr(struct dentry *dentry, const char *name) ovl_path_upper(dentry, &realpath); } + old_cred = ovl_override_creds(dentry->d_sb); err = vfs_removexattr(realpath.dentry, name); + revert_creds(old_cred); out_drop_write: ovl_drop_write(dentry); out: return err; } +struct posix_acl *ovl_get_acl(struct inode *inode, int type) +{ + struct inode *realinode = ovl_inode_real(inode, NULL); + const struct cred *old_cred; + struct posix_acl *acl; + + if (!IS_POSIXACL(realinode)) + return NULL; + + if (!realinode->i_op->get_acl) + return NULL; + + old_cred = ovl_override_creds(inode->i_sb); + acl = realinode->i_op->get_acl(realinode, type); + revert_creds(old_cred); + + return acl; +} + static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type, struct dentry *realdentry) { @@ -372,14 +363,39 @@ int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) return err; } +int ovl_update_time(struct inode *inode, struct timespec *ts, int flags) +{ + struct dentry *alias; + struct path upperpath; + + if (!(flags & S_ATIME)) + return 0; + + alias = d_find_any_alias(inode); + if (!alias) + return 0; + + ovl_path_upper(alias, &upperpath); + if (upperpath.dentry) { + touch_atime(&upperpath); + inode->i_atime = d_inode(upperpath.dentry)->i_atime; + } + + dput(alias); + + return 0; +} + static const struct inode_operations ovl_file_inode_operations = { .setattr = ovl_setattr, .permission = ovl_permission, .getattr = ovl_getattr, - .setxattr = ovl_setxattr, + .setxattr = generic_setxattr, .getxattr = ovl_getxattr, .listxattr = ovl_listxattr, .removexattr = ovl_removexattr, + .get_acl = ovl_get_acl, + .update_time = ovl_update_time, }; static const struct inode_operations ovl_symlink_inode_operations = { @@ -387,29 +403,22 @@ static const struct inode_operations ovl_symlink_inode_operations = { .get_link = ovl_get_link, .readlink = ovl_readlink, .getattr = ovl_getattr, - .setxattr = ovl_setxattr, + .setxattr = generic_setxattr, .getxattr = ovl_getxattr, .listxattr = ovl_listxattr, .removexattr = ovl_removexattr, + .update_time = ovl_update_time, }; -struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, - struct ovl_entry *oe) +static void ovl_fill_inode(struct inode *inode, umode_t mode) { - struct inode *inode; - - inode = new_inode(sb); - if (!inode) - return NULL; - inode->i_ino = get_next_ino(); inode->i_mode = mode; - inode->i_flags |= S_NOATIME | S_NOCMTIME; + inode->i_flags |= S_NOCMTIME; mode &= S_IFMT; switch (mode) { case S_IFDIR: - inode->i_private = oe; inode->i_op = &ovl_dir_inode_operations; inode->i_fop = &ovl_dir_operations; break; @@ -418,6 +427,10 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, inode->i_op = &ovl_symlink_inode_operations; break; + default: + WARN(1, "illegal file type: %i\n", mode); + /* Fall through */ + case S_IFREG: case S_IFSOCK: case S_IFBLK: @@ -425,11 +438,42 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, case S_IFIFO: inode->i_op = &ovl_file_inode_operations; break; + } +} - default: - WARN(1, "illegal file type: %i\n", mode); - iput(inode); - inode = NULL; +struct inode *ovl_new_inode(struct super_block *sb, umode_t mode) +{ + struct inode *inode; + + inode = new_inode(sb); + if (inode) + ovl_fill_inode(inode, mode); + + return inode; +} + +static int ovl_inode_test(struct inode *inode, void *data) +{ + return ovl_inode_real(inode, NULL) == data; +} + +static int ovl_inode_set(struct inode *inode, void *data) +{ + inode->i_private = (void *) (((unsigned long) data) | OVL_ISUPPER_MASK); + return 0; +} + +struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode) + +{ + struct inode *inode; + + inode = iget5_locked(sb, (unsigned long) realinode, + ovl_inode_test, ovl_inode_set, realinode); + if (inode && inode->i_state & I_NEW) { + ovl_fill_inode(inode, realinode->i_mode); + set_nlink(inode, realinode->i_nlink); + unlock_new_inode(inode); } return inode; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 0d3f2ad45708..e4f5c9536bfe 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -23,9 +23,11 @@ enum ovl_path_type { #define OVL_TYPE_MERGE_OR_LOWER(type) \ (OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type)) -#define OVL_XATTR_PRE_NAME "trusted.overlay." -#define OVL_XATTR_PRE_LEN 16 -#define OVL_XATTR_OPAQUE OVL_XATTR_PRE_NAME"opaque" + +#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay" +#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX ".opaque" + +#define OVL_ISUPPER_MASK 1UL static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) { @@ -131,6 +133,16 @@ static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) return err; } +static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper) +{ + unsigned long x = (unsigned long) READ_ONCE(inode->i_private); + + if (is_upper) + *is_upper = x & OVL_ISUPPER_MASK; + + return (struct inode *) (x & ~OVL_ISUPPER_MASK); +} + enum ovl_path_type ovl_path_type(struct dentry *dentry); u64 ovl_dentry_version_get(struct dentry *dentry); void ovl_dentry_version_inc(struct dentry *dentry); @@ -141,11 +153,9 @@ int ovl_path_next(int idx, 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_real(struct dentry *dentry); -struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper); struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode, bool is_upper); struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry); -bool ovl_is_default_permissions(struct inode *inode); void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache); struct dentry *ovl_workdir(struct dentry *dentry); int ovl_want_write(struct dentry *dentry); @@ -155,6 +165,7 @@ void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque); bool ovl_is_whiteout(struct dentry *dentry); const struct cred *ovl_override_creds(struct super_block *sb); void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry); +void ovl_inode_update(struct inode *inode, struct inode *upperinode); struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); struct file *ovl_path_open(struct path *path, int flags); @@ -179,15 +190,20 @@ ssize_t ovl_getxattr(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); int ovl_removexattr(struct dentry *dentry, const char *name); +struct posix_acl *ovl_get_acl(struct inode *inode, int type); int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); +int ovl_update_time(struct inode *inode, struct timespec *ts, int flags); -struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, - struct ovl_entry *oe); +struct inode *ovl_new_inode(struct super_block *sb, umode_t mode); +struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode); static inline void ovl_copyattr(struct inode *from, struct inode *to) { to->i_uid = from->i_uid; to->i_gid = from->i_gid; to->i_mode = from->i_mode; + to->i_atime = from->i_atime; + to->i_mtime = from->i_mtime; + to->i_ctime = from->i_ctime; } /* dir.c */ diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 5e254b3a8c56..4036132842b5 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -16,10 +16,10 @@ #include <linux/slab.h> #include <linux/parser.h> #include <linux/module.h> -#include <linux/pagemap.h> #include <linux/sched.h> #include <linux/statfs.h> #include <linux/seq_file.h> +#include <linux/posix_acl_xattr.h> #include "overlayfs.h" MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); @@ -145,18 +145,11 @@ struct dentry *ovl_dentry_real(struct dentry *dentry) return realdentry; } -struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper) +static void ovl_inode_init(struct inode *inode, struct inode *realinode, + bool is_upper) { - struct dentry *realdentry; - - realdentry = ovl_upperdentry_dereference(oe); - if (realdentry) { - *is_upper = true; - } else { - realdentry = __ovl_dentry_lower(oe); - *is_upper = false; - } - return realdentry; + WRITE_ONCE(inode->i_private, (unsigned long) realinode | + (is_upper ? OVL_ISUPPER_MASK : 0)); } struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode, @@ -178,13 +171,6 @@ struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) return oe->cache; } -bool ovl_is_default_permissions(struct inode *inode) -{ - struct ovl_fs *ofs = inode->i_sb->s_fs_info; - - return ofs->config.default_permissions; -} - void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) { struct ovl_entry *oe = dentry->d_fsdata; @@ -235,7 +221,6 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode)); WARN_ON(oe->__upperdentry); - BUG_ON(!upperdentry->d_inode); /* * Make sure upperdentry is consistent before making it visible to * ovl_upperdentry_dereference(). @@ -244,6 +229,16 @@ void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) oe->__upperdentry = upperdentry; } +void ovl_inode_update(struct inode *inode, struct inode *upperinode) +{ + WARN_ON(!upperinode); + WARN_ON(!inode_unhashed(inode)); + WRITE_ONCE(inode->i_private, + (unsigned long) upperinode | OVL_ISUPPER_MASK); + if (!S_ISDIR(upperinode->i_mode)) + __insert_inode_hash(inode, (unsigned long) upperinode); +} + void ovl_dentry_version_inc(struct dentry *dentry) { struct ovl_entry *oe = dentry->d_fsdata; @@ -340,7 +335,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry, /* Handle recursion */ return d_real(real, inode, open_flags); bug: - WARN(1, "ovl_d_real(%pd4, %s:%lu\n): real dentry not found\n", dentry, + WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); return dentry; } @@ -412,7 +407,8 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) static bool ovl_dentry_remote(struct dentry *dentry) { return dentry->d_flags & - (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); + (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | + DCACHE_OP_REAL); } static bool ovl_dentry_weird(struct dentry *dentry) @@ -423,12 +419,16 @@ static bool ovl_dentry_weird(struct dentry *dentry) DCACHE_OP_COMPARE); } -static inline struct dentry *ovl_lookup_real(struct dentry *dir, - struct qstr *name) +static inline struct dentry *ovl_lookup_real(struct super_block *ovl_sb, + struct dentry *dir, + const struct qstr *name) { + const struct cred *old_cred; struct dentry *dentry; - dentry = lookup_hash(name, dir); + old_cred = ovl_override_creds(ovl_sb); + dentry = lookup_one_len_unlocked(name->name, dir, name->len); + revert_creds(old_cred); if (IS_ERR(dentry)) { if (PTR_ERR(dentry) == -ENOENT) @@ -481,7 +481,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, upperdir = ovl_upperdentry_dereference(poe); if (upperdir) { - this = ovl_lookup_real(upperdir, &dentry->d_name); + this = ovl_lookup_real(dentry->d_sb, upperdir, &dentry->d_name); err = PTR_ERR(this); if (IS_ERR(this)) goto out; @@ -514,7 +514,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, bool opaque = false; struct path lowerpath = poe->lowerstack[i]; - this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name); + this = ovl_lookup_real(dentry->d_sb, + lowerpath.dentry, &dentry->d_name); err = PTR_ERR(this); if (IS_ERR(this)) { /* @@ -569,12 +570,19 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, if (upperdentry || ctr) { struct dentry *realdentry; + struct inode *realinode; realdentry = upperdentry ? upperdentry : stack[0].dentry; + realinode = d_inode(realdentry); err = -ENOMEM; - inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode, - oe); + if (upperdentry && !d_is_dir(upperdentry)) { + inode = ovl_get_inode(dentry->d_sb, realinode); + } else { + inode = ovl_new_inode(dentry->d_sb, realinode->i_mode); + if (inode) + ovl_inode_init(inode, realinode, !!upperdentry); + } if (!inode) goto out_free_oe; ovl_copyattr(realdentry->d_inode, inode); @@ -603,7 +611,7 @@ out: struct file *ovl_path_open(struct path *path, int flags) { - return dentry_open(path, flags, current_cred()); + return dentry_open(path, flags | O_NOATIME, current_cred()); } static void ovl_put_super(struct super_block *sb) @@ -686,6 +694,7 @@ static const struct super_operations ovl_super_operations = { .statfs = ovl_statfs, .show_options = ovl_show_options, .remount_fs = ovl_remount, + .drop_inode = generic_delete_inode, }; enum { @@ -958,11 +967,102 @@ static unsigned int ovl_split_lowerdirs(char *str) return ctr; } +static int ovl_posix_acl_xattr_set(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + struct dentry *workdir = ovl_workdir(dentry); + struct inode *realinode = ovl_inode_real(inode, NULL); + struct posix_acl *acl = NULL; + int err; + + /* Check that everything is OK before copy-up */ + if (value) { + acl = posix_acl_from_xattr(&init_user_ns, value, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + } + err = -EOPNOTSUPP; + if (!IS_POSIXACL(d_inode(workdir))) + goto out_acl_release; + if (!realinode->i_op->set_acl) + goto out_acl_release; + if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { + err = acl ? -EACCES : 0; + goto out_acl_release; + } + err = -EPERM; + if (!inode_owner_or_capable(inode)) + goto out_acl_release; + + posix_acl_release(acl); + + return ovl_setxattr(dentry, inode, handler->name, value, size, flags); + +out_acl_release: + posix_acl_release(acl); + return err; +} + +static int ovl_other_xattr_set(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + return ovl_setxattr(dentry, inode, name, value, size, flags); +} + +static int ovl_own_xattr_set(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + return -EPERM; +} + +static const struct xattr_handler ovl_posix_acl_access_xattr_handler = { + .name = XATTR_NAME_POSIX_ACL_ACCESS, + .flags = ACL_TYPE_ACCESS, + .set = ovl_posix_acl_xattr_set, +}; + +static const struct xattr_handler ovl_posix_acl_default_xattr_handler = { + .name = XATTR_NAME_POSIX_ACL_DEFAULT, + .flags = ACL_TYPE_DEFAULT, + .set = ovl_posix_acl_xattr_set, +}; + +static const struct xattr_handler ovl_own_xattr_handler = { + .prefix = OVL_XATTR_PREFIX, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_other_xattr_handler = { + .prefix = "", /* catch all */ + .set = ovl_other_xattr_set, +}; + +static const struct xattr_handler *ovl_xattr_handlers[] = { + &ovl_posix_acl_access_xattr_handler, + &ovl_posix_acl_default_xattr_handler, + &ovl_own_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +static const struct xattr_handler *ovl_xattr_noacl_handlers[] = { + &ovl_own_xattr_handler, + &ovl_other_xattr_handler, + NULL, +}; + static int ovl_fill_super(struct super_block *sb, void *data, int silent) { struct path upperpath = { NULL, NULL }; struct path workpath = { NULL, NULL }; struct dentry *root_dentry; + struct inode *realinode; struct ovl_entry *oe; struct ovl_fs *ufs; struct path *stack = NULL; @@ -1069,6 +1169,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) pr_err("overlayfs: failed to clone upperpath\n"); goto out_put_lowerpath; } + /* Don't inherit atime flags */ + ufs->upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); + + sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran; ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); err = PTR_ERR(ufs->workdir); @@ -1116,7 +1220,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) * Make lower_mnt R/O. That way fchmod/fchown on lower file * will fail instead of modifying lower fs. */ - mnt->mnt_flags |= MNT_READONLY; + mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; ufs->lower_mnt[ufs->numlower] = mnt; ufs->numlower++; @@ -1140,7 +1244,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (!oe) goto out_put_cred; - root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe)); + root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR)); if (!root_dentry) goto out_free_oe; @@ -1159,13 +1263,19 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) root_dentry->d_fsdata = oe; - ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode, - root_dentry->d_inode); + realinode = d_inode(ovl_dentry_real(root_dentry)); + ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry); + ovl_copyattr(realinode, d_inode(root_dentry)); sb->s_magic = OVERLAYFS_SUPER_MAGIC; sb->s_op = &ovl_super_operations; + if (IS_ENABLED(CONFIG_FS_POSIX_ACL)) + sb->s_xattr = ovl_xattr_handlers; + else + sb->s_xattr = ovl_xattr_noacl_handlers; sb->s_root = root_dentry; sb->s_fs_info = ufs; + sb->s_flags |= MS_POSIXACL; return 0; |