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linux/fs/gfs2/acl.c
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

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
static const char *gfs2_acl_name(int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
return GFS2_POSIX_ACL_ACCESS;
case ACL_TYPE_DEFAULT:
return GFS2_POSIX_ACL_DEFAULT;
}
return NULL;
}
struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct posix_acl *acl;
const char *name;
char *data;
int len;
if (!ip->i_eattr)
return NULL;
acl = get_cached_acl(&ip->i_inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
name = gfs2_acl_name(type);
if (name == NULL)
return ERR_PTR(-EINVAL);
len = gfs2_xattr_acl_get(ip, name, &data);
if (len < 0)
return ERR_PTR(len);
if (len == 0)
return NULL;
acl = posix_acl_from_xattr(&init_user_ns, data, len);
kfree(data);
return acl;
}
static int gfs2_set_mode(struct inode *inode, umode_t mode)
{
int error = 0;
if (mode != inode->i_mode) {
inode->i_mode = mode;
mark_inode_dirty(inode);
}
return error;
}
static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
{
int error;
int len;
char *data;
const char *name = gfs2_acl_name(type);
BUG_ON(name == NULL);
len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
if (len == 0)
return 0;
data = kmalloc(len, GFP_NOFS);
if (data == NULL)
return -ENOMEM;
error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
if (error < 0)
goto out;
error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
if (!error)
set_cached_acl(inode, type, acl);
out:
kfree(data);
return error;
}
int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
{
struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
struct posix_acl *acl;
umode_t mode = inode->i_mode;
int error = 0;
if (!sdp->sd_args.ar_posix_acl)
return 0;
if (S_ISLNK(inode->i_mode))
return 0;
acl = gfs2_get_acl(&dip->i_inode, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl) {
mode &= ~current_umask();
return gfs2_set_mode(inode, mode);
}
if (S_ISDIR(inode->i_mode)) {
error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
if (error)
goto out;
}
error = posix_acl_create(&acl, GFP_NOFS, &mode);
if (error < 0)
return error;
if (error == 0)
goto munge;
error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
if (error)
goto out;
munge:
error = gfs2_set_mode(inode, mode);
out:
posix_acl_release(acl);
return error;
}
int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
struct inode *inode = &ip->i_inode;
struct posix_acl *acl;
char *data;
unsigned int len;
int error;
acl = gfs2_get_acl(&ip->i_inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl)
return gfs2_setattr_simple(inode, attr);
error = posix_acl_chmod(&acl, GFP_NOFS, attr->ia_mode);
if (error)
return error;
len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
data = kmalloc(len, GFP_NOFS);
error = -ENOMEM;
if (data == NULL)
goto out;
posix_acl_to_xattr(&init_user_ns, acl, data, len);
error = gfs2_xattr_acl_chmod(ip, attr, data);
kfree(data);
set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
out:
posix_acl_release(acl);
return error;
}
static int gfs2_acl_type(const char *name)
{
if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
return ACL_TYPE_ACCESS;
if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
return ACL_TYPE_DEFAULT;
return -EINVAL;
}
static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int xtype)
{
struct inode *inode = dentry->d_inode;
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct posix_acl *acl;
int type;
int error;
if (!sdp->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
type = gfs2_acl_type(name);
if (type < 0)
return type;
acl = gfs2_get_acl(inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl == NULL)
return -ENODATA;
error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
posix_acl_release(acl);
return error;
}
static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags,
int xtype)
{
struct inode *inode = dentry->d_inode;
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct posix_acl *acl = NULL;
int error = 0, type;
if (!sdp->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
type = gfs2_acl_type(name);
if (type < 0)
return type;
if (flags & XATTR_CREATE)
return -EINVAL;
if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return value ? -EACCES : 0;
if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
return -EPERM;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!value)
goto set_acl;
acl = posix_acl_from_xattr(&init_user_ns, value, size);
if (!acl) {
/*
* acl_set_file(3) may request that we set default ACLs with
* zero length -- defend (gracefully) against that here.
*/
goto out;
}
if (IS_ERR(acl)) {
error = PTR_ERR(acl);
goto out;
}
error = posix_acl_valid(acl);
if (error)
goto out_release;
error = -EINVAL;
if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
goto out_release;
if (type == ACL_TYPE_ACCESS) {
umode_t mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error <= 0) {
posix_acl_release(acl);
acl = NULL;
if (error < 0)
return error;
}
error = gfs2_set_mode(inode, mode);
if (error)
goto out_release;
}
set_acl:
error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
if (!error) {
if (acl)
set_cached_acl(inode, type, acl);
else
forget_cached_acl(inode, type);
}
out_release:
posix_acl_release(acl);
out:
return error;
}
const struct xattr_handler gfs2_xattr_system_handler = {
.prefix = XATTR_SYSTEM_PREFIX,
.flags = GFS2_EATYPE_SYS,
.get = gfs2_xattr_system_get,
.set = gfs2_xattr_system_set,
};
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