fs/gfs2/acl.c - maze/linux - Git at Google

 /*
  * 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 "gfs2.h"
 #include "lm_interface.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;
 }
	/*
	* 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 "gfs2.h"
	#include "lm_interface.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;
	}