static int ovl_copy_up_last(struct dentry *dentry, struct iattr *attr,
bool no_data)
{
int err;
struct dentry *parent;
struct kstat stat;
struct path lowerpath;
parent = dget_parent(dentry);
err = ovl_copy_up(parent);
if (err)
goto out_dput_parent;
ovl_path_lower(dentry, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
if (err)
goto out_dput_parent;
if (no_data)
stat.size = 0;
err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat, attr);
out_dput_parent:
dput(parent);
return err;
}
struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
{
int err;
struct path realpath;
enum ovl_path_type type;
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
err = ovl_want_write(dentry);
if (err)
return ERR_PTR(err);
if (file_flags & O_TRUNC)
err = ovl_copy_up_last(dentry, NULL, true);
else
err = ovl_copy_up(dentry);
ovl_drop_write(dentry);
if (err)
return ERR_PTR(err);
ovl_path_upper(dentry, &realpath);
}
return d_backing_inode(realpath.dentry);
}
int ovl_removexattr(struct dentry *dentry, const char *name)
{
int err;
struct path realpath;
enum ovl_path_type type;
err = ovl_want_write(dentry);
if (err)
goto out;
if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
ovl_is_private_xattr(name))
goto out_drop_write;
type = ovl_path_real(dentry, &realpath);
if (type == OVL_PATH_LOWER) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
ovl_path_upper(dentry, &realpath);
}
err = vfs_removexattr(realpath.dentry, name);
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
int ovl_removexattr(struct dentry *dentry, const char *name)
{
int err;
struct path realpath;
enum ovl_path_type type;
if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
ovl_is_private_xattr(name))
return -ENODATA;
type = ovl_path_real(dentry, &realpath);
if (type == OVL_PATH_LOWER) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (err < 0)
return err;
err = ovl_copy_up(dentry);
if (err)
return err;
ovl_path_upper(dentry, &realpath);
}
return vfs_removexattr(realpath.dentry, name);
}
struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
{
int err;
struct path realpath;
enum ovl_path_type type;
if (d_is_dir(dentry))
return d_backing_inode(dentry);
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
err = ovl_want_write(dentry);
if (err)
return ERR_PTR(err);
if (file_flags & O_TRUNC)
err = ovl_copy_up_truncate(dentry);
else
err = ovl_copy_up(dentry);
ovl_drop_write(dentry);
if (err)
return ERR_PTR(err);
ovl_path_upper(dentry, &realpath);
}
if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);
return d_backing_inode(realpath.dentry);
}
static int ovl_dentry_open(struct dentry *dentry, struct file *file,
const struct cred *cred)
{
int err;
struct path realpath;
enum ovl_path_type type;
bool want_write = false;
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
want_write = true;
err = ovl_want_write(dentry);
if (err)
goto out;
if (file->f_flags & O_TRUNC)
err = ovl_copy_up_last(dentry, NULL, true);
else
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
ovl_path_upper(dentry, &realpath);
}
err = vfs_open(&realpath, file, cred);
out_drop_write:
if (want_write)
ovl_drop_write(dentry);
out:
return err;
}
int ovl_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
int err;
struct dentry *upperdentry;
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);
err = vfs_setxattr(upperdentry, name, value, size, flags);
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
int ovl_removexattr(struct dentry *dentry, const char *name)
{
int err;
struct path realpath;
enum ovl_path_type type = ovl_path_real(dentry, &realpath);
err = ovl_want_write(dentry);
if (err)
goto out;
err = -ENODATA;
if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
goto out_drop_write;
if (!OVL_TYPE_UPPER(type)) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
ovl_path_upper(dentry, &realpath);
}
err = vfs_removexattr(realpath.dentry, name);
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
int err;
struct dentry *upperdentry;
/*
* Check for permissions before trying to copy-up. This is redundant
* since it will be rechecked later by ->setattr() on upper dentry. But
* without this, copy-up can be triggered by just about anybody.
*
* We don't initialize inode->size, which just means that
* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
* check for a swapfile (which this won't be anyway).
*/
err = inode_change_ok(dentry->d_inode, attr);
if (err)
return err;
err = ovl_want_write(dentry);
if (err)
goto out;
if (attr->ia_valid & ATTR_SIZE) {
struct inode *realinode = d_inode(ovl_dentry_real(dentry));
err = -ETXTBSY;
if (atomic_read(&realinode->i_writecount) < 0)
goto out_drop_write;
}
err = ovl_copy_up(dentry);
if (!err) {
struct inode *winode = NULL;
upperdentry = ovl_dentry_upper(dentry);
if (attr->ia_valid & ATTR_SIZE) {
winode = d_inode(upperdentry);
err = get_write_access(winode);
if (err)
goto out_drop_write;
}
inode_lock(upperdentry->d_inode);
err = notify_change(upperdentry, attr, NULL);
if (!err)
ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
inode_unlock(upperdentry->d_inode);
if (winode)
put_write_access(winode);
}
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
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;
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;
err = -ENOMEM;
override_cred = prepare_creds();
if (!override_cred)
goto out_iput;
/*
* CAP_SYS_ADMIN for setting opaque xattr
* CAP_DAC_OVERRIDE for create in workdir, rename
* CAP_FOWNER for removing whiteout from sticky dir
*/
cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
cap_raise(override_cred->cap_effective, CAP_FOWNER);
old_cred = override_creds(override_cred);
err = ovl_create_over_whiteout(dentry, inode, &stat, link,
hardlink);
revert_creds(old_cred);
put_cred(override_cred);
}
if (!err)
inode = NULL;
out_iput:
iput(inode);
out:
return err;
}
int ovl_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
int err;
struct dentry *upperdentry;
if (ovl_is_private_xattr(name))
return -EPERM;
err = ovl_copy_up(dentry);
if (err)
return err;
upperdentry = ovl_dentry_upper(dentry);
return vfs_setxattr(upperdentry, name, value, size, flags);
}
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
* since it will be rechecked later by ->setattr() on upper dentry. But
* without this, copy-up can be triggered by just about anybody.
*
* We don't initialize inode->size, which just means that
* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
* check for a swapfile (which this won't be anyway).
*/
err = setattr_prepare(dentry, attr);
if (err)
return err;
err = ovl_want_write(dentry);
if (err)
goto out;
err = ovl_copy_up(dentry);
if (!err) {
upperdentry = ovl_dentry_upper(dentry);
if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
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);
}
ovl_drop_write(dentry);
out:
return err;
}
static struct file *ovl_open(struct dentry *dentry, struct file *file,
const struct cred *cred)
{
int err;
struct path realpath;
enum ovl_path_type type;
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
if (file->f_flags & O_TRUNC)
err = ovl_copy_up_truncate(dentry, 0);
else
err = ovl_copy_up(dentry);
if (err)
return ERR_PTR(err);
ovl_path_upper(dentry, &realpath);
}
return vfs_open(&realpath, file, cred);
}
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
int err;
struct dentry *upperdentry = ovl_i_dentry_upper(inode);
struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
const struct cred *old_cred;
err = ovl_want_write(dentry);
if (err)
goto out;
if (!value && !upperdentry) {
err = vfs_getxattr(realdentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
}
if (!upperdentry) {
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
realdentry = ovl_dentry_upper(dentry);
}
old_cred = ovl_override_creds(dentry->d_sb);
if (value)
err = vfs_setxattr(realdentry, name, value, size, flags);
else {
WARN_ON(flags != XATTR_REPLACE);
err = vfs_removexattr(realdentry, name);
}
revert_creds(old_cred);
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags)
{
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)
goto out;
if (!value && !OVL_TYPE_UPPER(type)) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
}
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
if (!OVL_TYPE_UPPER(type))
ovl_path_upper(dentry, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
if (value)
err = vfs_setxattr(realpath.dentry, name, value, size, flags);
else {
WARN_ON(flags != XATTR_REPLACE);
err = vfs_removexattr(realpath.dentry, name);
}
revert_creds(old_cred);
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
struct dentry *upperdentry;
int err;
if ((attr->ia_valid & ATTR_SIZE) && !ovl_dentry_upper(dentry))
err = ovl_copy_up_truncate(dentry, attr->ia_size);
else
err = ovl_copy_up(dentry);
if (err)
return err;
upperdentry = ovl_dentry_upper(dentry);
if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
attr->ia_valid &= ~ATTR_MODE;
mutex_lock(&upperdentry->d_inode->i_mutex);
err = notify_change(upperdentry, attr);
mutex_unlock(&upperdentry->d_inode->i_mutex);
return err;
}
static int ovl_copy_up_truncate(struct dentry *dentry)
{
int err;
struct dentry *parent;
struct kstat stat;
struct path lowerpath;
parent = dget_parent(dentry);
err = ovl_copy_up(parent);
if (err)
goto out_dput_parent;
ovl_path_lower(dentry, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
if (err)
goto out_dput_parent;
stat.size = 0;
err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
out_dput_parent:
dput(parent);
return err;
}
static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
struct ovl_cattr *cattr)
{
struct dentry *workdir = ovl_workdir(dentry);
struct inode *wdir = workdir->d_inode;
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *upper;
struct dentry *newdentry;
int err;
struct posix_acl *acl, *default_acl;
bool hardlink = !!cattr->hardlink;
if (WARN_ON(!workdir))
return -EROFS;
if (!hardlink) {
err = posix_acl_create(dentry->d_parent->d_inode,
&cattr->mode, &default_acl, &acl);
if (err)
return err;
}
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_unlock;
newdentry = ovl_create_temp(workdir, cattr);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_dput;
/*
* mode could have been mutilated due to umask (e.g. sgid directory)
*/
if (!hardlink &&
!S_ISLNK(cattr->mode) &&
newdentry->d_inode->i_mode != cattr->mode) {
struct iattr attr = {
.ia_valid = ATTR_MODE,
.ia_mode = cattr->mode,
};
inode_lock(newdentry->d_inode);
err = notify_change(newdentry, &attr, NULL);
inode_unlock(newdentry->d_inode);
if (err)
goto out_cleanup;
}
if (!hardlink) {
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
acl);
if (err)
goto out_cleanup;
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
default_acl);
if (err)
goto out_cleanup;
}
if (!hardlink && S_ISDIR(cattr->mode)) {
err = ovl_set_opaque(dentry, newdentry);
if (err)
goto out_cleanup;
err = ovl_do_rename(wdir, newdentry, udir, upper,
RENAME_EXCHANGE);
if (err)
goto out_cleanup;
ovl_cleanup(wdir, upper);
} else {
err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
if (err)
goto out_cleanup;
}
err = ovl_instantiate(dentry, inode, newdentry, hardlink);
if (err)
goto out_cleanup;
out_dput:
dput(upper);
out_unlock:
unlock_rename(workdir, upperdir);
out:
if (!hardlink) {
posix_acl_release(acl);
posix_acl_release(default_acl);
}
return err;
out_cleanup:
ovl_cleanup(wdir, newdentry);
dput(newdentry);
goto out_dput;
}
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct ovl_cattr *attr, bool origin)
{
int err;
const struct cred *old_cred;
struct cred *override_cred;
struct dentry *parent = dentry->d_parent;
err = ovl_copy_up(parent);
if (err)
return err;
old_cred = ovl_override_creds(dentry->d_sb);
/*
* When linking a file with copy up origin into a new parent, mark the
* new parent dir "impure".
*/
if (origin) {
err = ovl_set_impure(parent, ovl_dentry_upper(parent));
if (err)
goto out_revert_creds;
}
err = -ENOMEM;
override_cred = prepare_creds();
if (override_cred) {
override_cred->fsuid = inode->i_uid;
override_cred->fsgid = inode->i_gid;
if (!attr->hardlink) {
err = security_dentry_create_files_as(dentry,
attr->mode, &dentry->d_name, old_cred,
override_cred);
if (err) {
put_cred(override_cred);
goto out_revert_creds;
}
}
put_cred(override_creds(override_cred));
put_cred(override_cred);
if (!ovl_dentry_is_whiteout(dentry))
err = ovl_create_upper(dentry, inode, attr);
else
err = ovl_create_over_whiteout(dentry, inode, attr);
}
out_revert_creds:
revert_creds(old_cred);
return err;
}
static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
{
struct dentry *workdir = ovl_workdir(dentry);
struct inode *wdir = workdir->d_inode;
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *upper;
struct dentry *newdentry;
int err;
struct posix_acl *acl, *default_acl;
if (WARN_ON(!workdir))
return -EROFS;
if (!hardlink) {
err = posix_acl_create(dentry->d_parent->d_inode,
&stat->mode, &default_acl, &acl);
if (err)
return err;
}
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
newdentry = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_dput;
err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
if (err)
goto out_dput2;
/*
* 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) {
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
acl);
if (err)
goto out_cleanup;
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
default_acl);
if (err)
goto out_cleanup;
}
if (!hardlink && S_ISDIR(stat->mode)) {
err = ovl_set_opaque(newdentry);
if (err)
goto out_cleanup;
err = ovl_do_rename(wdir, newdentry, udir, upper,
RENAME_EXCHANGE);
if (err)
goto out_cleanup;
ovl_cleanup(wdir, upper);
} else {
err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
if (err)
goto out_cleanup;
}
ovl_instantiate(dentry, inode, newdentry, !!hardlink);
newdentry = NULL;
out_dput2:
dput(upper);
out_dput:
dput(newdentry);
out_unlock:
unlock_rename(workdir, upperdir);
out:
if (!hardlink) {
posix_acl_release(acl);
posix_acl_release(default_acl);
}
return err;
out_cleanup:
ovl_cleanup(wdir, newdentry);
goto out_dput2;
}
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
{
int err;
const struct cred *old_cred;
struct cred *override_cred;
err = ovl_copy_up(dentry->d_parent);
if (err)
return err;
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));
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;
}