linux/include/linux/posix_acl_xattr.h
Eric W. Biederman 5f3a4a28ec userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr
- Pass the user namespace the uid and gid values in the xattr are stored
   in into posix_acl_from_xattr.

 - Pass the user namespace kuid and kgid values should be converted into
   when storing uid and gid values in an xattr in posix_acl_to_xattr.

- Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to
  pass in &init_user_ns.

In the short term this change is not strictly needed but it makes the
code clearer.  In the longer term this change is necessary to be able to
mount filesystems outside of the initial user namespace that natively
store posix acls in the linux xattr format.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:35 -07:00

73 lines
1.8 KiB
C

/*
File: linux/posix_acl_xattr.h
Extended attribute system call representation of Access Control Lists.
Copyright (C) 2000 by Andreas Gruenbacher <a.gruenbacher@computer.org>
Copyright (C) 2002 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
*/
#ifndef _POSIX_ACL_XATTR_H
#define _POSIX_ACL_XATTR_H
#include <linux/posix_acl.h>
/* Extended attribute names */
#define POSIX_ACL_XATTR_ACCESS "system.posix_acl_access"
#define POSIX_ACL_XATTR_DEFAULT "system.posix_acl_default"
/* Supported ACL a_version fields */
#define POSIX_ACL_XATTR_VERSION 0x0002
/* An undefined entry e_id value */
#define ACL_UNDEFINED_ID (-1)
typedef struct {
__le16 e_tag;
__le16 e_perm;
__le32 e_id;
} posix_acl_xattr_entry;
typedef struct {
__le32 a_version;
posix_acl_xattr_entry a_entries[0];
} posix_acl_xattr_header;
static inline size_t
posix_acl_xattr_size(int count)
{
return (sizeof(posix_acl_xattr_header) +
(count * sizeof(posix_acl_xattr_entry)));
}
static inline int
posix_acl_xattr_count(size_t size)
{
if (size < sizeof(posix_acl_xattr_header))
return -1;
size -= sizeof(posix_acl_xattr_header);
if (size % sizeof(posix_acl_xattr_entry))
return -1;
return size / sizeof(posix_acl_xattr_entry);
}
#ifdef CONFIG_FS_POSIX_ACL
void posix_acl_fix_xattr_from_user(void *value, size_t size);
void posix_acl_fix_xattr_to_user(void *value, size_t size);
#else
static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
{
}
static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
{
}
#endif
struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
const void *value, size_t size);
int posix_acl_to_xattr(struct user_namespace *user_ns,
const struct posix_acl *acl, void *buffer, size_t size);
#endif /* _POSIX_ACL_XATTR_H */