[net-next-2.6.git] / fs / gfs2 / acl.c

/*
 * 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;
}

static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
{
	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(data, len);
	kfree(data);
	return acl;
}

/**
 * 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 posix_acl *acl;
	int error;

	acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
	if (IS_ERR(acl))
		return PTR_ERR(acl);

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

	return -EAGAIN;
}

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_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(acl, NULL, 0);
	if (len == 0)
		return 0;
	data = kmalloc(len, GFP_NOFS);
	if (data == NULL)
		return -ENOMEM;
	error = posix_acl_to_xattr(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, *clone;
	mode_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_acl_get(dip, ACL_TYPE_DEFAULT);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (!acl) {
		mode &= ~current_umask();
		if (mode != inode->i_mode)
			error = gfs2_set_mode(inode, mode);
		return error;
	}

	if (S_ISDIR(inode->i_mode)) {
		error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
		if (error)
			goto out;
	}

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

	error = posix_acl_create_masq(acl, &mode);
	if (error < 0)
		goto out;
	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 posix_acl *acl, *clone;
	char *data;
	unsigned int len;
	int error;

	acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	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) {
		len = posix_acl_to_xattr(acl, NULL, 0);
		data = kmalloc(len, GFP_NOFS);
		error = -ENOMEM;
		if (data == NULL)
			goto out;
		posix_acl_to_xattr(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_acl_get(GFS2_I(inode), type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;

	error = posix_acl_to_xattr(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(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, 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,
};
Commit	Line	Data
b3b94faa DT	1	/*
b3b94faa DT	2	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3a8a9a10	3	* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
b3b94faa DT	4	*
	5	* This copyrighted material is made available to anyone wishing to use,
	6	* modify, copy, or redistribute it subject to the terms and conditions
e9fc2aa0	7	* of the GNU General Public License version 2.
b3b94faa DT	8	*/
	9
	10	#include <linux/sched.h>
	11	#include <linux/slab.h>
	12	#include <linux/spinlock.h>
	13	#include <linux/completion.h>
	14	#include <linux/buffer_head.h>
2646a1f6	15	#include <linux/xattr.h>
b3b94faa DT	16	#include <linux/posix_acl.h>
b3b94faa DT	17	#include <linux/posix_acl_xattr.h>
5c676f6d	18	#include <linux/gfs2_ondisk.h>
b3b94faa DT	19
b3b94faa DT	20	#include "gfs2.h"
5c676f6d	21	#include "incore.h"
b3b94faa	22	#include "acl.h"
307cf6e6	23	#include "xattr.h"
b3b94faa DT	24	#include "glock.h"
	25	#include "inode.h"
	26	#include "meta_io.h"
	27	#include "trans.h"
5c676f6d	28	#include "util.h"
b3b94faa	29
479c427d	30	static const char *gfs2_acl_name(int type)
b3b94faa	31	{
479c427d SW	32	switch (type) {
	33	case ACL_TYPE_ACCESS:
	34	return GFS2_POSIX_ACL_ACCESS;
	35	case ACL_TYPE_DEFAULT:
	36	return GFS2_POSIX_ACL_DEFAULT;
	37	}
	38	return NULL;
	39	}
b3b94faa	40
479c427d SW	41	static struct posix_acl gfs2_acl_get(struct gfs2_inode ip, int type)
	42	{
	43	struct posix_acl *acl;
	44	const char *name;
	45	char *data;
	46	int len;
40b78a32	47
3767ac21	48	if (!ip->i_eattr)
479c427d	49	return NULL;
b3b94faa	50
106381bf SW	51	acl = get_cached_acl(&ip->i_inode, type);
	52	if (acl != ACL_NOT_CACHED)
	53	return acl;
	54
479c427d SW	55	name = gfs2_acl_name(type);
	56	if (name == NULL)
	57	return ERR_PTR(-EINVAL);
b3b94faa	58
479c427d SW	59	len = gfs2_xattr_acl_get(ip, name, &data);
	60	if (len < 0)
	61	return ERR_PTR(len);
	62	if (len == 0)
	63	return NULL;
b3b94faa	64
479c427d SW	65	acl = posix_acl_from_xattr(data, len);
	66	kfree(data);
	67	return acl;
b3b94faa DT	68	}
	69
	70	/**
77386e1f	71	* gfs2_check_acl - Check an ACL to see if we're allowed to do something
b3b94faa DT	72	* @inode: the file we want to do something to
	73	* @mask: what we want to do
	74	*
	75	* Returns: errno
	76	*/
	77
77386e1f	78	int gfs2_check_acl(struct inode *inode, int mask)
b3b94faa	79	{
479c427d	80	struct posix_acl *acl;
b3b94faa DT	81	int error;
b3b94faa DT	82
479c427d SW	83	acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
	84	if (IS_ERR(acl))
	85	return PTR_ERR(acl);
b3b94faa DT	86
	87	if (acl) {
	88	error = posix_acl_permission(inode, acl, mask);
	89	posix_acl_release(acl);
	90	return error;
	91	}
	92
	93	return -EAGAIN;
	94	}
	95
69dca424	96	static int gfs2_set_mode(struct inode *inode, mode_t mode)
b3b94faa	97	{
69dca424	98	int error = 0;
b3b94faa	99
69dca424 SW	100	if (mode != inode->i_mode) {
69dca424 SW	101	struct iattr iattr;
b3b94faa	102
69dca424 SW	103	iattr.ia_valid = ATTR_MODE;
69dca424 SW	104	iattr.ia_mode = mode;
b3b94faa	105
69dca424 SW	106	error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
69dca424 SW	107	}
b3b94faa	108
69dca424	109	return error;
b3b94faa DT	110	}
b3b94faa DT	111
479c427d	112	static int gfs2_acl_set(struct inode inode, int type, struct posix_acl acl)
b3b94faa	113	{
b3b94faa	114	int error;
479c427d SW	115	int len;
	116	char *data;
	117	const char *name = gfs2_acl_name(type);
	118
	119	BUG_ON(name == NULL);
	120	len = posix_acl_to_xattr(acl, NULL, 0);
	121	if (len == 0)
	122	return 0;
	123	data = kmalloc(len, GFP_NOFS);
	124	if (data == NULL)
	125	return -ENOMEM;
	126	error = posix_acl_to_xattr(acl, data, len);
	127	if (error < 0)
	128	goto out;
431547b3	129	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
106381bf SW	130	if (!error)
106381bf SW	131	set_cached_acl(inode, type, acl);
479c427d SW	132	out:
	133	kfree(data);
	134	return error;
	135	}
	136
	137	int gfs2_acl_create(struct gfs2_inode dip, struct inode inode)
	138	{
	139	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	140	struct posix_acl acl, clone;
	141	mode_t mode = inode->i_mode;
	142	int error = 0;
b3b94faa DT	143
	144	if (!sdp->sd_args.ar_posix_acl)
	145	return 0;
479c427d	146	if (S_ISLNK(inode->i_mode))
b3b94faa DT	147	return 0;
b3b94faa DT	148
479c427d SW	149	acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
	150	if (IS_ERR(acl))
	151	return PTR_ERR(acl);
b3b94faa	152	if (!acl) {
ce3b0f8d	153	mode &= ~current_umask();
479c427d SW	154	if (mode != inode->i_mode)
479c427d SW	155	error = gfs2_set_mode(inode, mode);
b3b94faa DT	156	return error;
	157	}
	158
479c427d SW	159	if (S_ISDIR(inode->i_mode)) {
	160	error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
	161	if (error)
	162	goto out;
	163	}
	164
16c5f06f	165	clone = posix_acl_clone(acl, GFP_NOFS);
b3b94faa DT	166	error = -ENOMEM;
	167	if (!clone)
	168	goto out;
	169	posix_acl_release(acl);
	170	acl = clone;
	171
b3b94faa DT	172	error = posix_acl_create_masq(acl, &mode);
	173	if (error < 0)
	174	goto out;
40b78a32 SW	175	if (error == 0)
40b78a32 SW	176	goto munge;
b3b94faa	177
479c427d	178	error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
40b78a32 SW	179	if (error)
	180	goto out;
	181	munge:
479c427d	182	error = gfs2_set_mode(inode, mode);
a91ea69f	183	out:
b3b94faa	184	posix_acl_release(acl);
b3b94faa DT	185	return error;
	186	}
	187
	188	int gfs2_acl_chmod(struct gfs2_inode ip, struct iattr attr)
	189	{
479c427d	190	struct posix_acl acl, clone;
b3b94faa DT	191	char *data;
	192	unsigned int len;
	193	int error;
	194
479c427d SW	195	acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
	196	if (IS_ERR(acl))
	197	return PTR_ERR(acl);
b3b94faa DT	198	if (!acl)
	199	return gfs2_setattr_simple(ip, attr);
	200
16c5f06f	201	clone = posix_acl_clone(acl, GFP_NOFS);
b3b94faa DT	202	error = -ENOMEM;
	203	if (!clone)
	204	goto out;
	205	posix_acl_release(acl);
	206	acl = clone;
	207
	208	error = posix_acl_chmod_masq(acl, attr->ia_mode);
	209	if (!error) {
479c427d SW	210	len = posix_acl_to_xattr(acl, NULL, 0);
	211	data = kmalloc(len, GFP_NOFS);
	212	error = -ENOMEM;
	213	if (data == NULL)
	214	goto out;
b3b94faa	215	posix_acl_to_xattr(acl, data, len);
479c427d SW	216	error = gfs2_xattr_acl_chmod(ip, attr, data);
479c427d SW	217	kfree(data);
106381bf	218	set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
b3b94faa DT	219	}
b3b94faa DT	220
a91ea69f	221	out:
b3b94faa	222	posix_acl_release(acl);
b3b94faa DT	223	return error;
	224	}
	225
2646a1f6 SW	226	static int gfs2_acl_type(const char *name)
	227	{
	228	if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
	229	return ACL_TYPE_ACCESS;
	230	if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
	231	return ACL_TYPE_DEFAULT;
	232	return -EINVAL;
	233	}
	234
431547b3 CH	235	static int gfs2_xattr_system_get(struct dentry dentry, const char name,
431547b3 CH	236	void *buffer, size_t size, int xtype)
2646a1f6	237	{
431547b3	238	struct inode *inode = dentry->d_inode;
f72f2d2e	239	struct gfs2_sbd *sdp = GFS2_SB(inode);
106381bf	240	struct posix_acl *acl;
2646a1f6	241	int type;
106381bf	242	int error;
2646a1f6	243
f72f2d2e SW	244	if (!sdp->sd_args.ar_posix_acl)
	245	return -EOPNOTSUPP;
	246
2646a1f6 SW	247	type = gfs2_acl_type(name);
	248	if (type < 0)
	249	return type;
	250
106381bf SW	251	acl = gfs2_acl_get(GFS2_I(inode), type);
	252	if (IS_ERR(acl))
	253	return PTR_ERR(acl);
	254	if (acl == NULL)
	255	return -ENODATA;
2646a1f6	256
106381bf SW	257	error = posix_acl_to_xattr(acl, buffer, size);
	258	posix_acl_release(acl);
	259
	260	return error;
	261	}
2646a1f6	262
431547b3 CH	263	static int gfs2_xattr_system_set(struct dentry dentry, const char name,
	264	const void *value, size_t size, int flags,
	265	int xtype)
2646a1f6	266	{
431547b3	267	struct inode *inode = dentry->d_inode;
2646a1f6 SW	268	struct gfs2_sbd *sdp = GFS2_SB(inode);
	269	struct posix_acl *acl = NULL;
	270	int error = 0, type;
	271
	272	if (!sdp->sd_args.ar_posix_acl)
	273	return -EOPNOTSUPP;
	274
	275	type = gfs2_acl_type(name);
	276	if (type < 0)
	277	return type;
	278	if (flags & XATTR_CREATE)
	279	return -EINVAL;
	280	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
	281	return value ? -EACCES : 0;
	282	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
	283	return -EPERM;
	284	if (S_ISLNK(inode->i_mode))
	285	return -EOPNOTSUPP;
	286
	287	if (!value)
	288	goto set_acl;
	289
	290	acl = posix_acl_from_xattr(value, size);
	291	if (!acl) {
	292	/*
	293	* acl_set_file(3) may request that we set default ACLs with
	294	* zero length -- defend (gracefully) against that here.
	295	*/
	296	goto out;
	297	}
	298	if (IS_ERR(acl)) {
	299	error = PTR_ERR(acl);
	300	goto out;
	301	}
	302
	303	error = posix_acl_valid(acl);
	304	if (error)
	305	goto out_release;
	306
	307	error = -EINVAL;
	308	if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
	309	goto out_release;
	310
	311	if (type == ACL_TYPE_ACCESS) {
	312	mode_t mode = inode->i_mode;
	313	error = posix_acl_equiv_mode(acl, &mode);
	314
	315	if (error <= 0) {
	316	posix_acl_release(acl);
	317	acl = NULL;
	318
	319	if (error < 0)
	320	return error;
	321	}
	322
	323	error = gfs2_set_mode(inode, mode);
	324	if (error)
	325	goto out_release;
	326	}
	327
	328	set_acl:
431547b3	329	error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
106381bf SW	330	if (!error) {
	331	if (acl)
	332	set_cached_acl(inode, type, acl);
	333	else
	334	forget_cached_acl(inode, type);
	335	}
2646a1f6 SW	336	out_release:
	337	posix_acl_release(acl);
	338	out:
	339	return error;
	340	}
	341
b7bb0a12	342	const struct xattr_handler gfs2_xattr_system_handler = {
2646a1f6	343	.prefix = XATTR_SYSTEM_PREFIX,
431547b3	344	.flags = GFS2_EATYPE_SYS,
2646a1f6 SW	345	.get = gfs2_xattr_system_get,
	346	.set = gfs2_xattr_system_set,
	347	};
	348