fs/gfs2/acl.c - 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/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 int acl_get(struct gfs2_inode *ip, const char *name,
 		   struct posix_acl **acl, struct gfs2_ea_location *el,
 		   char **datap, unsigned int *lenp)
 {
 	char *data;
 	unsigned int len;
 	int error;

 	el->el_bh = NULL;

 	if (!ip->i_eattr)
 		return 0;

 	error = gfs2_ea_find(ip, GFS2_EATYPE_SYS, name, el);
 	if (error)
 		return error;
 	if (!el->el_ea)
 		return 0;
 	if (!GFS2_EA_DATA_LEN(el->el_ea))
 		goto out;

 	len = GFS2_EA_DATA_LEN(el->el_ea);
 	data = kmalloc(len, GFP_NOFS);
 	error = -ENOMEM;
 	if (!data)
 		goto out;

 	error = gfs2_ea_get_copy(ip, el, data, len);
 	if (error < 0)
 		goto out_kfree;
 	error = 0;

 	if (acl) {
 		*acl = posix_acl_from_xattr(data, len);
 		if (IS_ERR(*acl))
 			error = PTR_ERR(*acl);
 	}

 out_kfree:
 	if (error || !datap) {
 		kfree(data);
 	} else {
 		*datap = data;
 		*lenp = len;
 	}
 out:
 	return error;
 }

 /**
  * gfs2_check_acl - 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(struct inode *inode, int mask)
 {
 	struct gfs2_ea_location el;
 	struct posix_acl *acl = NULL;
 	int error;

 	error = acl_get(GFS2_I(inode), GFS2_POSIX_ACL_ACCESS, &acl, &el, NULL, NULL);
 	brelse(el.el_bh);
 	if (error)
 		return error;

 	if (acl) {
 		error = posix_acl_permission(inode, acl, mask);
 		posix_acl_release(acl);
 		return error;
 	}

 	return -EAGAIN;
 }

 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_inode.i_mode & S_IFMT) == (mode & S_IFMT));
 		ip->i_inode.i_mode = mode;
 		gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 		gfs2_dinode_out(ip, 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_ea_location el;
 	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
 	struct posix_acl *acl = NULL, *clone;
 	mode_t mode = ip->i_inode.i_mode;
 	char *data = NULL;
 	unsigned int len;
 	int error;

 	if (!sdp->sd_args.ar_posix_acl)
 		return 0;
 	if (S_ISLNK(ip->i_inode.i_mode))
 		return 0;

 	error = acl_get(dip, GFS2_POSIX_ACL_DEFAULT, &acl, &el, &data, &len);
 	brelse(el.el_bh);
 	if (error)
 		return error;
 	if (!acl) {
 		mode &= ~current_umask();
 		if (mode != ip->i_inode.i_mode)
 			error = munge_mode(ip, mode);
 		return error;
 	}

 	clone = posix_acl_clone(acl, GFP_NOFS);
 	error = -ENOMEM;
 	if (!clone)
 		goto out;
 	posix_acl_release(acl);
 	acl = clone;

 	if (S_ISDIR(ip->i_inode.i_mode)) {
 		error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
 				       GFS2_POSIX_ACL_DEFAULT, data, len, 0);
 		if (error)
 			goto out;
 	}

 	error = posix_acl_create_masq(acl, &mode);
 	if (error < 0)
 		goto out;
 	if (error == 0)
 		goto munge;

 	posix_acl_to_xattr(acl, data, len);
 	error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
 			       GFS2_POSIX_ACL_ACCESS, data, len, 0);
 	if (error)
 		goto out;
 munge:
 	error = munge_mode(ip, mode);
 out:
 	posix_acl_release(acl);
 	kfree(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, GFS2_POSIX_ACL_ACCESS, &acl, &el, &data, &len);
 	if (error)
 		goto out_brelse;
 	if (!acl)
 		return gfs2_setattr_simple(ip, attr);

 	clone = posix_acl_clone(acl, GFP_NOFS);
 	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);
 	kfree(data);
 out_brelse:
 	brelse(el.el_bh);
 	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 inode *inode, const char *name,
 				 void *buffer, size_t size)
 {
 	int type;

 	type = gfs2_acl_type(name);
 	if (type < 0)
 		return type;

 	return gfs2_xattr_get(inode, GFS2_EATYPE_SYS, name, buffer, size);
 }

 static int gfs2_set_mode(struct inode *inode, mode_t mode)
 {
 	int error = 0;

 	if (mode != inode->i_mode) {
 		struct iattr iattr;

 		iattr.ia_valid = ATTR_MODE;
 		iattr.ia_mode = mode;

 		error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
 	}

 	return error;
 }

 static int gfs2_xattr_system_set(struct inode *inode, const char *name,
 				 const void *value, size_t size, int flags)
 {
 	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(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) {
 		mode_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, GFS2_EATYPE_SYS, name, value, size, 0);
 out_release:
 	posix_acl_release(acl);
 out:
 	return error;
 }

 struct xattr_handler gfs2_xattr_system_handler = {
 	.prefix = XATTR_SYSTEM_PREFIX,
 	.get    = gfs2_xattr_system_get,
 	.set    = gfs2_xattr_system_set,
 };
	/*
	* 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 int acl_get(struct gfs2_inode ip, const char name,
	struct posix_acl *acl, struct gfs2_ea_location el,
	char *datap, unsigned int lenp)
	{
	char *data;
	unsigned int len;
	int error;

	el->el_bh = NULL;

	if (!ip->i_eattr)
	return 0;

	error = gfs2_ea_find(ip, GFS2_EATYPE_SYS, name, el);
	if (error)
	return error;
	if (!el->el_ea)
	return 0;
	if (!GFS2_EA_DATA_LEN(el->el_ea))
	goto out;

	len = GFS2_EA_DATA_LEN(el->el_ea);
	data = kmalloc(len, GFP_NOFS);
	error = -ENOMEM;
	if (!data)
	goto out;

	error = gfs2_ea_get_copy(ip, el, data, len);
	if (error < 0)
	goto out_kfree;
	error = 0;

	if (acl) {
	*acl = posix_acl_from_xattr(data, len);
	if (IS_ERR(*acl))
	error = PTR_ERR(*acl);
	}

	out_kfree:
	if (error \|\| !datap) {
	kfree(data);
	} else {
	*datap = data;
	*lenp = len;
	}
	out:
	return error;
	}

	/**
	* gfs2_check_acl - 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(struct inode *inode, int mask)
	{
	struct gfs2_ea_location el;
	struct posix_acl *acl = NULL;
	int error;

	error = acl_get(GFS2_I(inode), GFS2_POSIX_ACL_ACCESS, &acl, &el, NULL, NULL);
	brelse(el.el_bh);
	if (error)
	return error;

	if (acl) {
	error = posix_acl_permission(inode, acl, mask);
	posix_acl_release(acl);
	return error;
	}

	return -EAGAIN;
	}

	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_inode.i_mode & S_IFMT) == (mode & S_IFMT));
	ip->i_inode.i_mode = mode;
	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
	gfs2_dinode_out(ip, 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_ea_location el;
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct posix_acl acl = NULL, clone;
	mode_t mode = ip->i_inode.i_mode;
	char *data = NULL;
	unsigned int len;
	int error;

	if (!sdp->sd_args.ar_posix_acl)
	return 0;
	if (S_ISLNK(ip->i_inode.i_mode))
	return 0;

	error = acl_get(dip, GFS2_POSIX_ACL_DEFAULT, &acl, &el, &data, &len);
	brelse(el.el_bh);
	if (error)
	return error;
	if (!acl) {
	mode &= ~current_umask();
	if (mode != ip->i_inode.i_mode)
	error = munge_mode(ip, mode);
	return error;
	}

	clone = posix_acl_clone(acl, GFP_NOFS);
	error = -ENOMEM;
	if (!clone)
	goto out;
	posix_acl_release(acl);
	acl = clone;

	if (S_ISDIR(ip->i_inode.i_mode)) {
	error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
	GFS2_POSIX_ACL_DEFAULT, data, len, 0);
	if (error)
	goto out;
	}

	error = posix_acl_create_masq(acl, &mode);
	if (error < 0)
	goto out;
	if (error == 0)
	goto munge;

	posix_acl_to_xattr(acl, data, len);
	error = gfs2_xattr_set(&ip->i_inode, GFS2_EATYPE_SYS,
	GFS2_POSIX_ACL_ACCESS, data, len, 0);
	if (error)
	goto out;
	munge:
	error = munge_mode(ip, mode);
	out:
	posix_acl_release(acl);
	kfree(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, GFS2_POSIX_ACL_ACCESS, &acl, &el, &data, &len);
	if (error)
	goto out_brelse;
	if (!acl)
	return gfs2_setattr_simple(ip, attr);

	clone = posix_acl_clone(acl, GFP_NOFS);
	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);
	kfree(data);
	out_brelse:
	brelse(el.el_bh);
	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 inode inode, const char name,
	void *buffer, size_t size)
	{
	int type;

	type = gfs2_acl_type(name);
	if (type < 0)
	return type;

	return gfs2_xattr_get(inode, GFS2_EATYPE_SYS, name, buffer, size);
	}

	static int gfs2_set_mode(struct inode *inode, mode_t mode)
	{
	int error = 0;

	if (mode != inode->i_mode) {
	struct iattr iattr;

	iattr.ia_valid = ATTR_MODE;
	iattr.ia_mode = mode;

	error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
	}

	return error;
	}

	static int gfs2_xattr_system_set(struct inode inode, const char name,
	const void *value, size_t size, int flags)
	{
	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(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) {
	mode_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, GFS2_EATYPE_SYS, name, value, size, 0);
	out_release:
	posix_acl_release(acl);
	out:
	return error;
	}

	struct xattr_handler gfs2_xattr_system_handler = {
	.prefix = XATTR_SYSTEM_PREFIX,
	.get = gfs2_xattr_system_get,
	.set = gfs2_xattr_system_set,
	};