init: add an init_chroot helper (4b7ca501) · Commits · 戴 / test

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);

+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));

+1 −6

Original line number	Diff line number	Diff line
		@@ -530,7 +530,7 @@ out:
		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 @@ out:
		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;

+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);

+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);