linux/fs/gfs2/acl.c

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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/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>
#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "eaops.h"
#include "eattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
#define ACL_ACCESS 1
#define ACL_DEFAULT 0
int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,
struct gfs2_ea_request *er,
int *remove, mode_t *mode)
{
struct posix_acl *acl;
int error;
error = gfs2_acl_validate_remove(ip, access);
if (error)
return error;
if (!er->er_data)
return -EINVAL;
acl = posix_acl_from_xattr(er->er_data, er->er_data_len);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl) {
*remove = 1;
return 0;
}
error = posix_acl_valid(acl);
if (error)
goto out;
if (access) {
error = posix_acl_equiv_mode(acl, mode);
if (!error)
*remove = 1;
else if (error > 0)
error = 0;
}
out:
posix_acl_release(acl);
return error;
}
int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access)
{
if (!GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
if (current->fsuid != ip->i_di.di_uid && !capable(CAP_FOWNER))
return -EPERM;
if (S_ISLNK(ip->i_di.di_mode))
return -EOPNOTSUPP;
if (!access && !S_ISDIR(ip->i_di.di_mode))
return -EACCES;
return 0;
}
static int acl_get(struct gfs2_inode *ip, int access, struct posix_acl **acl,
struct gfs2_ea_location *el, char **data, unsigned int *len)
{
struct gfs2_ea_request er;
struct gfs2_ea_location el_this;
int error;
if (!ip->i_di.di_eattr)
return 0;
memset(&er, 0, sizeof(struct gfs2_ea_request));
if (access) {
er.er_name = GFS2_POSIX_ACL_ACCESS;
er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
} else {
er.er_name = GFS2_POSIX_ACL_DEFAULT;
er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
}
er.er_type = GFS2_EATYPE_SYS;
if (!el)
el = &el_this;
error = gfs2_ea_find(ip, &er, el);
if (error)
return error;
if (!el->el_ea)
return 0;
if (!GFS2_EA_DATA_LEN(el->el_ea))
goto out;
er.er_data_len = GFS2_EA_DATA_LEN(el->el_ea);
er.er_data = kmalloc(er.er_data_len, GFP_KERNEL);
error = -ENOMEM;
if (!er.er_data)
goto out;
error = gfs2_ea_get_copy(ip, el, er.er_data);
if (error)
goto out_kfree;
if (acl) {
*acl = posix_acl_from_xattr(er.er_data, er.er_data_len);
if (IS_ERR(*acl))
error = PTR_ERR(*acl);
}
out_kfree:
if (error || !data)
kfree(er.er_data);
else {
*data = er.er_data;
*len = er.er_data_len;
}
out:
if (error || el == &el_this)
brelse(el->el_bh);
return error;
}
/**
* gfs2_check_acl_locked - Check an ACL to see if we're allowed to do something
* @inode: the file we want to do something to
* @mask: what we want to do
*
* Returns: errno
*/
int gfs2_check_acl_locked(struct inode *inode, int mask)
{
struct posix_acl *acl = NULL;
int error;
error = acl_get(GFS2_I(inode), ACL_ACCESS, &acl, NULL, NULL, NULL);
if (error)
return error;
if (acl) {
error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
int gfs2_check_acl(struct inode *inode, int mask)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder i_gh;
int error;
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
if (!error) {
error = gfs2_check_acl_locked(inode, mask);
gfs2_glock_dq_uninit(&i_gh);
}
return error;
}
static int munge_mode(struct gfs2_inode *ip, mode_t mode)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct buffer_head *dibh;
int error;
error = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (error)
return error;
error = gfs2_meta_inode_buffer(ip, &dibh);
if (!error) {
gfs2_assert_withdraw(sdp,
(ip->i_di.di_mode & S_IFMT) == (mode & S_IFMT));
ip->i_di.di_mode = mode;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(&ip->i_di, dibh->b_data);
brelse(dibh);
}
gfs2_trans_end(sdp);
return 0;
}
int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip)
{
struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
struct posix_acl *acl = NULL, *clone;
struct gfs2_ea_request er;
mode_t mode = ip->i_di.di_mode;
int error;
if (!sdp->sd_args.ar_posix_acl)
return 0;
if (S_ISLNK(ip->i_di.di_mode))
return 0;
memset(&er, 0, sizeof(struct gfs2_ea_request));
er.er_type = GFS2_EATYPE_SYS;
error = acl_get(dip, ACL_DEFAULT, &acl, NULL,
&er.er_data, &er.er_data_len);
if (error)
return error;
if (!acl) {
mode &= ~current->fs->umask;
if (mode != ip->i_di.di_mode)
error = munge_mode(ip, mode);
return error;
}
clone = posix_acl_clone(acl, GFP_KERNEL);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
if (S_ISDIR(ip->i_di.di_mode)) {
er.er_name = GFS2_POSIX_ACL_DEFAULT;
er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
error = gfs2_system_eaops.eo_set(ip, &er);
if (error)
goto out;
}
error = posix_acl_create_masq(acl, &mode);
if (error < 0)
goto out;
if (error > 0) {
er.er_name = GFS2_POSIX_ACL_ACCESS;
er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
posix_acl_to_xattr(acl, er.er_data, er.er_data_len);
er.er_mode = mode;
er.er_flags = GFS2_ERF_MODE;
error = gfs2_system_eaops.eo_set(ip, &er);
if (error)
goto out;
} else
munge_mode(ip, mode);
out:
posix_acl_release(acl);
kfree(er.er_data);
return error;
}
int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
struct posix_acl *acl = NULL, *clone;
struct gfs2_ea_location el;
char *data;
unsigned int len;
int error;
error = acl_get(ip, ACL_ACCESS, &acl, &el, &data, &len);
if (error)
return error;
if (!acl)
return gfs2_setattr_simple(ip, attr);
clone = posix_acl_clone(acl, GFP_KERNEL);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
error = posix_acl_chmod_masq(acl, attr->ia_mode);
if (!error) {
posix_acl_to_xattr(acl, data, len);
error = gfs2_ea_acl_chmod(ip, &el, attr, data);
}
out:
posix_acl_release(acl);
brelse(el.el_bh);
kfree(data);
return error;
}