Commit 4b7ca501 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

init: add an init_chroot helper 



Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_chroot.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent db63f1e3

drivers/base/devtmpfs.c

+1 −1
Original line number Diff line number Diff line
@@ -413,7 +413,7 @@ static int __init devtmpfs_setup(void *p) 
	if (err)

		goto out;

	init_chdir("/.."); /* will traverse into overmounted root */

	ksys_chroot(".");

	init_chroot(".");

out:

	*(int *)p = err;

	complete(&setup_done);

fs/init.c

+24 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#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,
@@ -54,6 +55,29 @@ int __init init_chdir(const char *filename) 
	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_unlink(const char *pathname)

{

	return do_unlinkat(AT_FDCWD, getname_kernel(pathname));

fs/open.c

+1 −6
Original line number Diff line number Diff line
@@ -530,7 +530,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) 
	return error;

}



int ksys_chroot(const char __user *filename)

SYSCALL_DEFINE1(chroot, const char __user *, filename)

{

	struct path path;

	int error;
@@ -563,11 +563,6 @@ int ksys_chroot(const char __user *filename) 
	return error;

}



SYSCALL_DEFINE1(chroot, const char __user *, filename)

{

	return ksys_chroot(filename);

}



static int chmod_common(const struct path *path, umode_t mode)

{

	struct inode *inode = path->dentry->d_inode;

include/linux/init_syscalls.h

+1 −0
Original line number Diff line number Diff line
@@ -4,5 +4,6 @@ int __init init_mount(const char *dev_name, const char *dir_name, 
		const char *type_page, unsigned long flags, void *data_page);

int __init init_umount(const char *name, int flags);

int __init init_chdir(const char *filename);

int __init init_chroot(const char *filename);

int __init init_unlink(const char *pathname);

int __init init_rmdir(const char *pathname);

include/linux/syscalls.h

+0 −2
Original line number Diff line number Diff line
@@ -1235,8 +1235,6 @@ asmlinkage long sys_ni_syscall(void); 
 * Instead, use one of the functions which work equivalently, such as

 * the ksys_xyzyyz() functions prototyped below.

 */



int ksys_chroot(const char __user *filename);

ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);

int ksys_fchown(unsigned int fd, uid_t user, gid_t group);

ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);