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// SPDX-License-Identifier: GPL-2.0
/*
* Routines that mimic syscalls, but don't use the user address space or file
* descriptors. Only for init/ and related early init code.
*/
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <linux/init_syscalls.h>
#include <linux/security.h>
#include "internal.h"
int __init init_mount(const char *dev_name, const char *dir_name,
const char *type_page, unsigned long flags, void *data_page)
{
struct path path;
int ret;
ret = kern_path(dir_name, LOOKUP_FOLLOW, &path);
if (ret)
return ret;
ret = path_mount(dev_name, &path, type_page, flags, data_page);
path_put(&path);
return ret;
}
int __init init_umount(const char *name, int flags)
{
int lookup_flags = LOOKUP_MOUNTPOINT;
struct path path;
int ret;
if (!(flags & UMOUNT_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
ret = kern_path(name, lookup_flags, &path);
if (ret)
return ret;
return path_umount(&path, flags);
}
int __init init_chdir(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &path);
path_put(&path);
return error;
}
int __init init_chroot(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
error = -EPERM;
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
goto dput_and_out;
error = security_path_chroot(&path);
if (error)
goto dput_and_out;
set_fs_root(current->fs, &path);
dput_and_out:
path_put(&path);
return error;
}
int __init init_chown(const char *filename, uid_t user, gid_t group, int flags)
{
int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
struct path path;
int error;
error = kern_path(filename, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = chown_common(&path, user, group);
mnt_drop_write(path.mnt);
}
path_put(&path);
return error;
}
int __init init_chmod(const char *filename, umode_t mode)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW, &path);
if (error)
return error;
error = chmod_common(&path, mode);
path_put(&path);
return error;
}
int __init init_eaccess(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW, &path);
if (error)
return error;
error = inode_permission(d_inode(path.dentry), MAY_ACCESS);
path_put(&path);
return error;
}
int __init init_mknod(const char *filename, umode_t mode, unsigned int dev)
{
struct dentry *dentry;
struct path path;
int error;
if (S_ISFIFO(mode) || S_ISSOCK(mode))
dev = 0;
else if (!(S_ISBLK(mode) || S_ISCHR(mode)))
return -EINVAL;
dentry = kern_path_create(AT_FDCWD, filename, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mknod(&path, dentry, mode, dev);
if (!error)
error = vfs_mknod(path.dentry->d_inode, dentry, mode,
new_decode_dev(dev));
done_path_create(&path, dentry);
return error;
}
int __init init_link(const char *oldname, const char *newname)
{
struct dentry *new_dentry;
struct path old_path, new_path;
int error;
error = kern_path(oldname, 0, &old_path);
if (error)
return error;
new_dentry = kern_path_create(AT_FDCWD, newname, &new_path, 0);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out;
error = -EXDEV;
if (old_path.mnt != new_path.mnt)
goto out_dput;
error = may_linkat(&old_path);
if (unlikely(error))
goto out_dput;
error = security_path_link(old_path.dentry, &new_path, new_dentry);
if (error)
goto out_dput;
error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry,
NULL);
out_dput:
done_path_create(&new_path, new_dentry);
out:
path_put(&old_path);
return error;
}
int __init init_symlink(const char *oldname, const char *newname)
{
struct dentry *dentry;
struct path path;
int error;
dentry = kern_path_create(AT_FDCWD, newname, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
error = security_path_symlink(&path, dentry, oldname);
if (!error)
error = vfs_symlink(path.dentry->d_inode, dentry, oldname);
done_path_create(&path, dentry);
return error;
}
int __init init_unlink(const char *pathname)
{
return do_unlinkat(AT_FDCWD, getname_kernel(pathname));
}
int __init init_mkdir(const char *pathname, umode_t mode)
{
struct dentry *dentry;
struct path path;
int error;
dentry = kern_path_create(AT_FDCWD, pathname, &path, LOOKUP_DIRECTORY);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mkdir(&path, dentry, mode);
if (!error)
error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
done_path_create(&path, dentry);
return error;
}
int __init init_rmdir(const char *pathname)
{
return do_rmdir(AT_FDCWD, getname_kernel(pathname));
}
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