[linux.git] / fs / xfs / xfs_acl.c

/*
 * Copyright (c) 2008, Christoph Hellwig
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_ag.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>


/*
 * Locking scheme:
 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 *    calling into this file.
 */

STATIC struct posix_acl *
xfs_acl_from_disk(
	struct xfs_acl	*aclp,
	int		max_entries)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	struct xfs_acl_entry *ace;
	unsigned int count, i;

	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries)
		return ERR_PTR(-EFSCORRUPTED);

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
		acl_e = &acl->a_entries[i];
		ace = &aclp->acl_entry[i];

		/*
		 * The tag is 32 bits on disk and 16 bits in core.
		 *
		 * Because every access to it goes through the core
		 * format first this is not a problem.
		 */
		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

		switch (acl_e->e_tag) {
		case ACL_USER:
			acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_GROUP:
			acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
			break;
		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			break;
		default:
			goto fail;
		}
	}
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
		ace = &aclp->acl_entry[i];
		acl_e = &acl->a_entries[i];

		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
		switch (acl_e->e_tag) {
		case ACL_USER:
			ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
			break;
		case ACL_GROUP:
			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
			break;
		default:
			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
			break;
		}

		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
}

struct posix_acl *
xfs_get_acl(struct inode *inode, int type)
{
	struct xfs_inode *ip = XFS_I(inode);
	struct posix_acl *acl = NULL;
	struct xfs_acl *xfs_acl;
	unsigned char *ea_name;
	int error;
	int len;

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		BUG();
	}

	/*
	 * If we have a cached ACLs value just return it, not need to
	 * go out to the disk.
	 */
	len = XFS_ACL_MAX_SIZE(ip->i_mount);
	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	if (!xfs_acl)
		return ERR_PTR(-ENOMEM);

	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
							&len, ATTR_ROOT);
	if (error) {
		/*
		 * If the attribute doesn't exist make sure we have a negative
		 * cache entry, for any other error assume it is transient and
		 * leave the cache entry as ACL_NOT_CACHED.
		 */
		if (error == -ENOATTR)
			goto out_update_cache;
		goto out;
	}

	acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
	if (IS_ERR(acl))
		goto out;

out_update_cache:
	set_cached_acl(inode, type, acl);
out:
	kmem_free(xfs_acl);
	return acl;
}

STATIC int
__xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
	struct xfs_inode *ip = XFS_I(inode);
	unsigned char *ea_name;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		ea_name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		ea_name = SGI_ACL_DEFAULT;
		break;
	default:
		return -EINVAL;
	}

	if (acl) {
		struct xfs_acl *xfs_acl;
		int len = XFS_ACL_MAX_SIZE(ip->i_mount);

		xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
		if (!xfs_acl)
			return -ENOMEM;

		xfs_acl_to_disk(xfs_acl, acl);

		/* subtract away the unused acl entries */
		len -= sizeof(struct xfs_acl_entry) *
			 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

		error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
				len, ATTR_ROOT);

		kmem_free(xfs_acl);
	} else {
		/*
		 * A NULL ACL argument means we want to remove the ACL.
		 */
		error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);

		/*
		 * If the attribute didn't exist to start with that's fine.
		 */
		if (error == -ENOATTR)
			error = 0;
	}

	if (!error)
		set_cached_acl(inode, type, acl);
	return error;
}

static int
xfs_set_mode(struct inode *inode, umode_t mode)
{
	int error = 0;

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

		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
		iattr.ia_mode = mode;
		iattr.ia_ctime = current_fs_time(inode->i_sb);

		error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	}

	return error;
}

static int
xfs_acl_exists(struct inode *inode, unsigned char *name)
{
	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));

	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
			    ATTR_ROOT|ATTR_KERNOVAL) == 0);
}

int
posix_acl_access_exists(struct inode *inode)
{
	return xfs_acl_exists(inode, SGI_ACL_FILE);
}

int
posix_acl_default_exists(struct inode *inode)
{
	if (!S_ISDIR(inode->i_mode))
		return 0;
	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
}

int
xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int error = 0;

	if (!acl)
		goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
		return error;

	if (type == ACL_TYPE_ACCESS) {
		umode_t mode = inode->i_mode;
		error = posix_acl_equiv_mode(acl, &mode);

		if (error <= 0) {
			acl = NULL;

			if (error < 0)
				return error;
		}

		error = xfs_set_mode(inode, mode);
		if (error)
			return error;
	}

 set_acl:
	return __xfs_set_acl(inode, type, acl);
}
Commit	Line	Data
ef14f0c1 CH	1	/*
	2	* Copyright (c) 2008, Christoph Hellwig
	3	* All Rights Reserved.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	17	*/
	18	#include "xfs.h"
a4fbe6ab	19	#include "xfs_format.h"
69432832	20	#include "xfs_log_format.h"
7fd36c44	21	#include "xfs_trans_resv.h"
9356fe22	22	#include "xfs_ag.h"
0a8aa193 DC	23	#include "xfs_sb.h"
0a8aa193 DC	24	#include "xfs_mount.h"
a4fbe6ab DC	25	#include "xfs_inode.h"
	26	#include "xfs_acl.h"
	27	#include "xfs_attr.h"
0b1b213f	28	#include "xfs_trace.h"
5a0e3ad6	29	#include <linux/slab.h>
ef14f0c1 CH	30	#include <linux/xattr.h>
	31	#include <linux/posix_acl_xattr.h>
	32
	33
ef14f0c1 CH	34	/*
	35	* Locking scheme:
	36	* - all ACL updates are protected by inode->i_mutex, which is taken before
	37	* calling into this file.
ef14f0c1 CH	38	*/
	39
	40	STATIC struct posix_acl *
0a8aa193 DC	41	xfs_acl_from_disk(
	42	struct xfs_acl *aclp,
	43	int max_entries)
ef14f0c1 CH	44	{
	45	struct posix_acl_entry *acl_e;
	46	struct posix_acl *acl;
	47	struct xfs_acl_entry *ace;
093019cf	48	unsigned int count, i;
ef14f0c1 CH	49
ef14f0c1 CH	50	count = be32_to_cpu(aclp->acl_cnt);
0a8aa193	51	if (count > max_entries)
fa8b18ed	52	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1 CH	53
	54	acl = posix_acl_alloc(count, GFP_KERNEL);
	55	if (!acl)
	56	return ERR_PTR(-ENOMEM);
	57
	58	for (i = 0; i < count; i++) {
	59	acl_e = &acl->a_entries[i];
	60	ace = &aclp->acl_entry[i];
	61
	62	/*
	63	* The tag is 32 bits on disk and 16 bits in core.
	64	*
	65	* Because every access to it goes through the core
	66	* format first this is not a problem.
	67	*/
	68	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	69	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	70
	71	switch (acl_e->e_tag) {
	72	case ACL_USER:
288bbe0e DE	73	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
288bbe0e DE	74	break;
ef14f0c1	75	case ACL_GROUP:
288bbe0e	76	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
ef14f0c1 CH	77	break;
	78	case ACL_USER_OBJ:
	79	case ACL_GROUP_OBJ:
	80	case ACL_MASK:
	81	case ACL_OTHER:
ef14f0c1 CH	82	break;
	83	default:
	84	goto fail;
	85	}
	86	}
	87	return acl;
	88
	89	fail:
	90	posix_acl_release(acl);
	91	return ERR_PTR(-EINVAL);
	92	}
	93
	94	STATIC void
	95	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	96	{
	97	const struct posix_acl_entry *acl_e;
	98	struct xfs_acl_entry *ace;
	99	int i;
	100
	101	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	102	for (i = 0; i < acl->a_count; i++) {
	103	ace = &aclp->acl_entry[i];
	104	acl_e = &acl->a_entries[i];
	105
	106	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	107	switch (acl_e->e_tag) {
	108	case ACL_USER:
	109	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	110	break;
	111	case ACL_GROUP:
	112	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	113	break;
	114	default:
	115	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	116	break;
	117	}
	118
ef14f0c1 CH	119	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	120	}
	121	}
	122
ef14f0c1 CH	123	struct posix_acl *
	124	xfs_get_acl(struct inode *inode, int type)
	125	{
	126	struct xfs_inode *ip = XFS_I(inode);
2401dc29	127	struct posix_acl *acl = NULL;
ef14f0c1	128	struct xfs_acl *xfs_acl;
a9273ca5	129	unsigned char *ea_name;
ef14f0c1	130	int error;
0a8aa193	131	int len;
ef14f0c1	132
4e34e719 CH	133	trace_xfs_get_acl(ip);
4e34e719 CH	134
ef14f0c1 CH	135	switch (type) {
	136	case ACL_TYPE_ACCESS:
	137	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	138	break;
	139	case ACL_TYPE_DEFAULT:
	140	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	141	break;
ef14f0c1 CH	142	default:
1cbd20d8	143	BUG();
ef14f0c1 CH	144	}
ef14f0c1 CH	145
ef14f0c1 CH	146	/*
	147	* If we have a cached ACLs value just return it, not need to
	148	* go out to the disk.
	149	*/
0a8aa193	150	len = XFS_ACL_MAX_SIZE(ip->i_mount);
fdd3ccee DC	151	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	152	if (!xfs_acl)
	153	return ERR_PTR(-ENOMEM);
ef14f0c1	154
2451337d	155	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
a9273ca5	156	&len, ATTR_ROOT);
ef14f0c1 CH	157	if (error) {
	158	/*
	159	* If the attribute doesn't exist make sure we have a negative
	160	* cache entry, for any other error assume it is transient and
1cbd20d8	161	* leave the cache entry as ACL_NOT_CACHED.
ef14f0c1	162	*/
2401dc29	163	if (error == -ENOATTR)
ef14f0c1	164	goto out_update_cache;
ef14f0c1 CH	165	goto out;
	166	}
	167
0a8aa193	168	acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
ef14f0c1 CH	169	if (IS_ERR(acl))
	170	goto out;
	171
2dc164f2	172	out_update_cache:
1cbd20d8	173	set_cached_acl(inode, type, acl);
2dc164f2	174	out:
fdd3ccee	175	kmem_free(xfs_acl);
ef14f0c1 CH	176	return acl;
	177	}
	178
	179	STATIC int
2401dc29	180	__xfs_set_acl(struct inode inode, int type, struct posix_acl acl)
ef14f0c1 CH	181	{
ef14f0c1 CH	182	struct xfs_inode *ip = XFS_I(inode);
a9273ca5	183	unsigned char *ea_name;
ef14f0c1 CH	184	int error;
ef14f0c1 CH	185
ef14f0c1 CH	186	switch (type) {
	187	case ACL_TYPE_ACCESS:
	188	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	189	break;
	190	case ACL_TYPE_DEFAULT:
	191	if (!S_ISDIR(inode->i_mode))
	192	return acl ? -EACCES : 0;
	193	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	194	break;
	195	default:
	196	return -EINVAL;
	197	}
	198
	199	if (acl) {
	200	struct xfs_acl *xfs_acl;
0a8aa193	201	int len = XFS_ACL_MAX_SIZE(ip->i_mount);
ef14f0c1	202
fdd3ccee DC	203	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	204	if (!xfs_acl)
	205	return -ENOMEM;
ef14f0c1 CH	206
ef14f0c1 CH	207	xfs_acl_to_disk(xfs_acl, acl);
0a8aa193 DC	208
	209	/* subtract away the unused acl entries */
	210	len -= sizeof(struct xfs_acl_entry) *
	211	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
ef14f0c1	212
2451337d	213	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
ef14f0c1 CH	214	len, ATTR_ROOT);
ef14f0c1 CH	215
fdd3ccee	216	kmem_free(xfs_acl);
ef14f0c1 CH	217	} else {
	218	/*
	219	* A NULL ACL argument means we want to remove the ACL.
	220	*/
2451337d	221	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
ef14f0c1 CH	222
	223	/*
	224	* If the attribute didn't exist to start with that's fine.
	225	*/
	226	if (error == -ENOATTR)
	227	error = 0;
	228	}
	229
	230	if (!error)
1cbd20d8	231	set_cached_acl(inode, type, acl);
ef14f0c1 CH	232	return error;
	233	}
	234
ef14f0c1	235	static int
d3fb6120	236	xfs_set_mode(struct inode *inode, umode_t mode)
ef14f0c1 CH	237	{
	238	int error = 0;
	239
	240	if (mode != inode->i_mode) {
	241	struct iattr iattr;
	242
d6d59bad	243	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
ef14f0c1	244	iattr.ia_mode = mode;
d6d59bad	245	iattr.ia_ctime = current_fs_time(inode->i_sb);
ef14f0c1	246
2451337d	247	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
ef14f0c1 CH	248	}
	249
	250	return error;
	251	}
	252
	253	static int
a9273ca5	254	xfs_acl_exists(struct inode inode, unsigned char name)
ef14f0c1	255	{
0a8aa193	256	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));
ef14f0c1 CH	257
	258	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
	259	ATTR_ROOT\|ATTR_KERNOVAL) == 0);
	260	}
	261
	262	int
	263	posix_acl_access_exists(struct inode *inode)
	264	{
	265	return xfs_acl_exists(inode, SGI_ACL_FILE);
	266	}
	267
	268	int
	269	posix_acl_default_exists(struct inode *inode)
	270	{
	271	if (!S_ISDIR(inode->i_mode))
	272	return 0;
	273	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
	274	}
	275
ef14f0c1	276	int
2401dc29	277	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	278	{
431547b3	279	int error = 0;
ef14f0c1	280
2401dc29	281	if (!acl)
ef14f0c1 CH	282	goto set_acl;
ef14f0c1 CH	283
4ae69fea	284	error = -E2BIG;
0a8aa193	285	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	286	return error;
ef14f0c1 CH	287
ef14f0c1 CH	288	if (type == ACL_TYPE_ACCESS) {
d6952123	289	umode_t mode = inode->i_mode;
ef14f0c1 CH	290	error = posix_acl_equiv_mode(acl, &mode);
	291
	292	if (error <= 0) {
ef14f0c1 CH	293	acl = NULL;
	294
	295	if (error < 0)
	296	return error;
	297	}
	298
	299	error = xfs_set_mode(inode, mode);
	300	if (error)
2401dc29	301	return error;
ef14f0c1 CH	302	}
	303
	304	set_acl:
2401dc29	305	return __xfs_set_acl(inode, type, acl);
ef14f0c1	306	}