Commit eb9d7d39 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

init: add an init_eaccess helper 



Add a simple helper to check if a file exists based on kernel space file
name and switch the early init code over to it.  Note that this
theoretically changes behavior as it always is based on the effective
permissions.  But during early init that doesn't make a difference.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 1097742e

fs/init.c

+13 −0
Original line number Diff line number Diff line
@@ -109,6 +109,19 @@ int __init init_chmod(const char *filename, umode_t mode) 
	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_unlink(const char *pathname)

{

	return do_unlinkat(AT_FDCWD, getname_kernel(pathname));

fs/open.c

+1 −1
Original line number Diff line number Diff line
@@ -394,7 +394,7 @@ static const struct cred *access_override_creds(void) 
	return old_cred;

}



long do_faccessat(int dfd, const char __user *filename, int mode, int flags)

static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)

{

	struct path path;

	struct inode *inode;

include/linux/init_syscalls.h

+1 −0
Original line number Diff line number Diff line
@@ -7,5 +7,6 @@ int __init init_chdir(const char *filename); 
int __init init_chroot(const char *filename);

int __init init_chown(const char *filename, uid_t user, gid_t group, int flags);

int __init init_chmod(const char *filename, umode_t mode);

int __init init_eaccess(const char *filename);

int __init init_unlink(const char *pathname);

int __init init_rmdir(const char *pathname);

include/linux/syscalls.h

+0 −7
Original line number Diff line number Diff line
@@ -1304,13 +1304,6 @@ static inline long ksys_link(const char __user *oldname, 
	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);

}



long do_faccessat(int dfd, const char __user *filename, int mode, int flags);



static inline long ksys_access(const char __user *filename, int mode)

{

	return do_faccessat(AT_FDCWD, filename, mode, 0);

}



extern int do_fchownat(int dfd, const char __user *filename, uid_t user,

		       gid_t group, int flag);

init/main.c

+2 −2
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ 
#include <linux/jump_label.h>

#include <linux/mem_encrypt.h>

#include <linux/kcsan.h>

#include <linux/init_syscalls.h>



#include <asm/io.h>

#include <asm/bugs.h>
@@ -1514,8 +1515,7 @@ static noinline void __init kernel_init_freeable(void) 
	 * check if there is an early userspace init.  If yes, let it do all

	 * the work

	 */

	if (ksys_access((const char __user *)

			ramdisk_execute_command, 0) != 0) {

	if (init_eaccess(ramdisk_execute_command) != 0) {

		ramdisk_execute_command = NULL;

		prepare_namespace();

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE