[mirror_ubuntu-hirsute-kernel.git] / fs / xfs / linux-2.6 / 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_acl.h"
#include "xfs_attr.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.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)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	struct xfs_acl_entry *ace;
	int count, i;

	count = be32_to_cpu(aclp->acl_cnt);

	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:
		case ACL_GROUP:
			acl_e->e_id = be32_to_cpu(ace->ae_id);
			break;
		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			acl_e->e_id = ACL_UNDEFINED_ID;
			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);
		ace->ae_id = cpu_to_be32(acl_e->e_id);
		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;
	struct xfs_acl *xfs_acl;
	int len = sizeof(struct xfs_acl);
	char *ea_name;
	int error;

	acl = get_cached_acl(inode, type);
	if (acl != ACL_NOT_CACHED)
		return acl;

	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.
	 */

	xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
	if (!xfs_acl)
		return ERR_PTR(-ENOMEM);

	error = -xfs_attr_get(ip, ea_name, (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) {
			acl = NULL;
			goto out_update_cache;
		}
		goto out;
	}

	acl = xfs_acl_from_disk(xfs_acl);
	if (IS_ERR(acl))
		goto out;

 out_update_cache:
	set_cached_acl(inode, type, acl);
 out:
	kfree(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);
	char *ea_name;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;

	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 = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
		if (!xfs_acl)
			return -ENOMEM;

		xfs_acl_to_disk(xfs_acl, acl);
		len = sizeof(struct xfs_acl) -
			(sizeof(struct xfs_acl_entry) *
			 (XFS_ACL_MAX_ENTRIES - acl->a_count));

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

		kfree(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;
}

int
xfs_check_acl(struct inode *inode, int mask)
{
	struct xfs_inode *ip = XFS_I(inode);
	struct posix_acl *acl;
	int error = -EAGAIN;

	xfs_itrace_entry(ip);

	/*
	 * If there is no attribute fork no ACL exists on this inode and
	 * we can skip the whole exercise.
	 */
	if (!XFS_IFORK_Q(ip))
		return -EAGAIN;

	acl = xfs_get_acl(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;
}

static int
xfs_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 = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	}

	return error;
}

static int
xfs_acl_exists(struct inode *inode, char *name)
{
	int len = sizeof(struct xfs_acl);

	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);
}

/*
 * No need for i_mutex because the inode is not yet exposed to the VFS.
 */
int
xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl)
{
	struct posix_acl *clone;
	mode_t mode;
	int error = 0, inherit = 0;

	if (S_ISDIR(inode->i_mode)) {
		error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl);
		if (error)
			return error;
	}

	clone = posix_acl_clone(default_acl, GFP_KERNEL);
	if (!clone)
		return -ENOMEM;

	mode = inode->i_mode;
	error = posix_acl_create_masq(clone, &mode);
	if (error < 0)
		goto out_release_clone;

	/*
	 * If posix_acl_create_masq returns a positive value we need to
	 * inherit a permission that can't be represented using the Unix
	 * mode bits and we actually need to set an ACL.
	 */
	if (error > 0)
		inherit = 1;

	error = xfs_set_mode(inode, mode);
	if (error)
		goto out_release_clone;

	if (inherit)
		error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);

 out_release_clone:
	posix_acl_release(clone);
	return error;
}

int
xfs_acl_chmod(struct inode *inode)
{
	struct posix_acl *acl, *clone;
	int error;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;

	acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(acl) || !acl)
		return PTR_ERR(acl);

	clone = posix_acl_clone(acl, GFP_KERNEL);
	posix_acl_release(acl);
	if (!clone)
		return -ENOMEM;

	error = posix_acl_chmod_masq(clone, inode->i_mode);
	if (!error)
		error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);

	posix_acl_release(clone);
	return error;
}

/*
 * System xattr handlers.
 *
 * Currently Posix ACLs are the only system namespace extended attribute
 * handlers supported by XFS, so we just implement the handlers here.
 * If we ever support other system extended attributes this will need
 * some refactoring.
 */

static int
xfs_decode_acl(const char *name)
{
	if (strcmp(name, "posix_acl_access") == 0)
		return ACL_TYPE_ACCESS;
	else if (strcmp(name, "posix_acl_default") == 0)
		return ACL_TYPE_DEFAULT;
	return -EINVAL;
}

static int
xfs_xattr_system_get(struct inode *inode, const char *name,
		void *value, size_t size)
{
	struct posix_acl *acl;
	int type, error;

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

	acl = xfs_get_acl(inode, type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;

	error = posix_acl_to_xattr(acl, value, size);
	posix_acl_release(acl);

	return error;
}

static int
xfs_xattr_system_set(struct inode *inode, const char *name,
		const void *value, size_t size, int flags)
{
	struct posix_acl *acl = NULL;
	int error = 0, type;

	type = xfs_decode_acl(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 (!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 > XFS_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 = xfs_set_mode(inode, mode);
		if (error)
			goto out_release;
	}

 set_acl:
	error = xfs_set_acl(inode, type, acl);
 out_release:
	posix_acl_release(acl);
 out:
	return error;
}

struct xattr_handler xfs_xattr_system_handler = {
	.prefix	= XATTR_SYSTEM_PREFIX,
	.get	= xfs_xattr_system_get,
	.set	= xfs_xattr_system_set,
};
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"
	19	#include "xfs_acl.h"
	20	#include "xfs_attr.h"
	21	#include "xfs_bmap_btree.h"
	22	#include "xfs_inode.h"
	23	#include "xfs_vnodeops.h"
0b1b213f	24	#include "xfs_trace.h"
ef14f0c1 CH	25	#include <linux/xattr.h>
	26	#include <linux/posix_acl_xattr.h>
	27
	28
ef14f0c1 CH	29	/*
	30	* Locking scheme:
	31	* - all ACL updates are protected by inode->i_mutex, which is taken before
	32	* calling into this file.
ef14f0c1 CH	33	*/
	34
	35	STATIC struct posix_acl *
	36	xfs_acl_from_disk(struct xfs_acl *aclp)
	37	{
	38	struct posix_acl_entry *acl_e;
	39	struct posix_acl *acl;
	40	struct xfs_acl_entry *ace;
	41	int count, i;
	42
	43	count = be32_to_cpu(aclp->acl_cnt);
	44
	45	acl = posix_acl_alloc(count, GFP_KERNEL);
	46	if (!acl)
	47	return ERR_PTR(-ENOMEM);
	48
	49	for (i = 0; i < count; i++) {
	50	acl_e = &acl->a_entries[i];
	51	ace = &aclp->acl_entry[i];
	52
	53	/*
	54	* The tag is 32 bits on disk and 16 bits in core.
	55	*
	56	* Because every access to it goes through the core
	57	* format first this is not a problem.
	58	*/
	59	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	60	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	61
	62	switch (acl_e->e_tag) {
	63	case ACL_USER:
	64	case ACL_GROUP:
	65	acl_e->e_id = be32_to_cpu(ace->ae_id);
	66	break;
	67	case ACL_USER_OBJ:
	68	case ACL_GROUP_OBJ:
	69	case ACL_MASK:
	70	case ACL_OTHER:
	71	acl_e->e_id = ACL_UNDEFINED_ID;
	72	break;
	73	default:
	74	goto fail;
	75	}
	76	}
	77	return acl;
	78
	79	fail:
	80	posix_acl_release(acl);
	81	return ERR_PTR(-EINVAL);
	82	}
	83
	84	STATIC void
	85	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	86	{
	87	const struct posix_acl_entry *acl_e;
	88	struct xfs_acl_entry *ace;
	89	int i;
	90
	91	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	92	for (i = 0; i < acl->a_count; i++) {
	93	ace = &aclp->acl_entry[i];
	94	acl_e = &acl->a_entries[i];
	95
	96	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
97	ace->ae_id = cpu_to_be32(acl_e->e_id);
98	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
99	}
100	}
101
ef14f0c1 CH	102	struct posix_acl *
	103	xfs_get_acl(struct inode *inode, int type)
	104	{
	105	struct xfs_inode *ip = XFS_I(inode);
1cbd20d8	106	struct posix_acl *acl;
ef14f0c1 CH	107	struct xfs_acl *xfs_acl;
	108	int len = sizeof(struct xfs_acl);
	109	char *ea_name;
	110	int error;
	111
1cbd20d8 AV	112	acl = get_cached_acl(inode, type);
	113	if (acl != ACL_NOT_CACHED)
	114	return acl;
	115
ef14f0c1 CH	116	switch (type) {
	117	case ACL_TYPE_ACCESS:
	118	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	119	break;
	120	case ACL_TYPE_DEFAULT:
	121	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	122	break;
ef14f0c1 CH	123	default:
1cbd20d8	124	BUG();
ef14f0c1 CH	125	}
ef14f0c1 CH	126
ef14f0c1 CH	127	/*
	128	* If we have a cached ACLs value just return it, not need to
	129	* go out to the disk.
	130	*/
ef14f0c1 CH	131
	132	xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
	133	if (!xfs_acl)
	134	return ERR_PTR(-ENOMEM);
	135
	136	error = -xfs_attr_get(ip, ea_name, (char *)xfs_acl, &len, ATTR_ROOT);
	137	if (error) {
	138	/*
	139	* If the attribute doesn't exist make sure we have a negative
	140	* cache entry, for any other error assume it is transient and
1cbd20d8	141	* leave the cache entry as ACL_NOT_CACHED.
ef14f0c1 CH	142	*/
	143	if (error == -ENOATTR) {
	144	acl = NULL;
	145	goto out_update_cache;
	146	}
	147	goto out;
	148	}
	149
	150	acl = xfs_acl_from_disk(xfs_acl);
	151	if (IS_ERR(acl))
	152	goto out;
	153
	154	out_update_cache:
1cbd20d8	155	set_cached_acl(inode, type, acl);
ef14f0c1 CH	156	out:
	157	kfree(xfs_acl);
	158	return acl;
	159	}
	160
	161	STATIC int
	162	xfs_set_acl(struct inode inode, int type, struct posix_acl acl)
	163	{
	164	struct xfs_inode *ip = XFS_I(inode);
ef14f0c1 CH	165	char *ea_name;
	166	int error;
	167
	168	if (S_ISLNK(inode->i_mode))
	169	return -EOPNOTSUPP;
	170
	171	switch (type) {
	172	case ACL_TYPE_ACCESS:
	173	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	174	break;
	175	case ACL_TYPE_DEFAULT:
	176	if (!S_ISDIR(inode->i_mode))
	177	return acl ? -EACCES : 0;
	178	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	179	break;
	180	default:
	181	return -EINVAL;
	182	}
	183
	184	if (acl) {
	185	struct xfs_acl *xfs_acl;
	186	int len;
	187
	188	xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
	189	if (!xfs_acl)
	190	return -ENOMEM;
	191
	192	xfs_acl_to_disk(xfs_acl, acl);
	193	len = sizeof(struct xfs_acl) -
	194	(sizeof(struct xfs_acl_entry) *
	195	(XFS_ACL_MAX_ENTRIES - acl->a_count));
	196
	197	error = -xfs_attr_set(ip, ea_name, (char *)xfs_acl,
	198	len, ATTR_ROOT);
	199
	200	kfree(xfs_acl);
	201	} else {
	202	/*
	203	* A NULL ACL argument means we want to remove the ACL.
	204	*/
	205	error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
	206
	207	/*
	208	* If the attribute didn't exist to start with that's fine.
	209	*/
	210	if (error == -ENOATTR)
	211	error = 0;
	212	}
	213
	214	if (!error)
1cbd20d8	215	set_cached_acl(inode, type, acl);
ef14f0c1 CH	216	return error;
	217	}
	218
	219	int
	220	xfs_check_acl(struct inode *inode, int mask)
	221	{
	222	struct xfs_inode *ip = XFS_I(inode);
	223	struct posix_acl *acl;
	224	int error = -EAGAIN;
	225
	226	xfs_itrace_entry(ip);
	227
	228	/*
	229	* If there is no attribute fork no ACL exists on this inode and
	230	* we can skip the whole exercise.
	231	*/
	232	if (!XFS_IFORK_Q(ip))
	233	return -EAGAIN;
	234
	235	acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
	236	if (IS_ERR(acl))
	237	return PTR_ERR(acl);
	238	if (acl) {
	239	error = posix_acl_permission(inode, acl, mask);
	240	posix_acl_release(acl);
	241	}
	242
	243	return error;
	244	}
	245
	246	static int
	247	xfs_set_mode(struct inode *inode, mode_t mode)
	248	{
	249	int error = 0;
	250
	251	if (mode != inode->i_mode) {
	252	struct iattr iattr;
	253
	254	iattr.ia_valid = ATTR_MODE;
	255	iattr.ia_mode = mode;
	256
	257	error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	258	}
	259
	260	return error;
	261	}
	262
	263	static int
	264	xfs_acl_exists(struct inode inode, char name)
	265	{
	266	int len = sizeof(struct xfs_acl);
	267
	268	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
	269	ATTR_ROOT\|ATTR_KERNOVAL) == 0);
	270	}
	271
	272	int
	273	posix_acl_access_exists(struct inode *inode)
	274	{
	275	return xfs_acl_exists(inode, SGI_ACL_FILE);
	276	}
	277
	278	int
	279	posix_acl_default_exists(struct inode *inode)
280	{
281	if (!S_ISDIR(inode->i_mode))
282	return 0;
283	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
284	}
285
286	/*
287	* No need for i_mutex because the inode is not yet exposed to the VFS.
288	*/
289	int
290	xfs_inherit_acl(struct inode inode, struct posix_acl default_acl)
291	{
292	struct posix_acl *clone;
293	mode_t mode;
294	int error = 0, inherit = 0;
295
296	if (S_ISDIR(inode->i_mode)) {
297	error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl);
298	if (error)
299	return error;
300	}
301
302	clone = posix_acl_clone(default_acl, GFP_KERNEL);
303	if (!clone)
304	return -ENOMEM;
305
306	mode = inode->i_mode;
307	error = posix_acl_create_masq(clone, &mode);
308	if (error < 0)
309	goto out_release_clone;
310
311	/*
312	* If posix_acl_create_masq returns a positive value we need to
313	* inherit a permission that can't be represented using the Unix
314	* mode bits and we actually need to set an ACL.
315	*/
316	if (error > 0)
317	inherit = 1;
318
319	error = xfs_set_mode(inode, mode);
320	if (error)
321	goto out_release_clone;
322
323	if (inherit)
324	error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
325
326	out_release_clone:
327	posix_acl_release(clone);
328	return error;
329	}
330
331	int
332	xfs_acl_chmod(struct inode *inode)
333	{
334	struct posix_acl acl, clone;
335	int error;
336
337	if (S_ISLNK(inode->i_mode))
338	return -EOPNOTSUPP;
339
340	acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
341	if (IS_ERR(acl) \|\| !acl)
342	return PTR_ERR(acl);
343
344	clone = posix_acl_clone(acl, GFP_KERNEL);
345	posix_acl_release(acl);
346	if (!clone)
347	return -ENOMEM;
348
349	error = posix_acl_chmod_masq(clone, inode->i_mode);
350	if (!error)
351	error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
352
353	posix_acl_release(clone);
354	return error;
355	}
356
ef14f0c1 CH	357	/*
	358	* System xattr handlers.
	359	*
	360	* Currently Posix ACLs are the only system namespace extended attribute
	361	* handlers supported by XFS, so we just implement the handlers here.
	362	* If we ever support other system extended attributes this will need
	363	* some refactoring.
	364	*/
	365
	366	static int
	367	xfs_decode_acl(const char *name)
	368	{
	369	if (strcmp(name, "posix_acl_access") == 0)
	370	return ACL_TYPE_ACCESS;
	371	else if (strcmp(name, "posix_acl_default") == 0)
	372	return ACL_TYPE_DEFAULT;
	373	return -EINVAL;
	374	}
	375
	376	static int
	377	xfs_xattr_system_get(struct inode inode, const char name,
	378	void *value, size_t size)
	379	{
	380	struct posix_acl *acl;
	381	int type, error;
	382
	383	type = xfs_decode_acl(name);
	384	if (type < 0)
	385	return type;
	386
	387	acl = xfs_get_acl(inode, type);
	388	if (IS_ERR(acl))
	389	return PTR_ERR(acl);
	390	if (acl == NULL)
	391	return -ENODATA;
	392
	393	error = posix_acl_to_xattr(acl, value, size);
	394	posix_acl_release(acl);
	395
	396	return error;
	397	}
	398
	399	static int
	400	xfs_xattr_system_set(struct inode inode, const char name,
	401	const void *value, size_t size, int flags)
	402	{
	403	struct posix_acl *acl = NULL;
	404	int error = 0, type;
	405
	406	type = xfs_decode_acl(name);
	407	if (type < 0)
	408	return type;
	409	if (flags & XATTR_CREATE)
	410	return -EINVAL;
	411	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
	412	return value ? -EACCES : 0;
	413	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
	414	return -EPERM;
	415
	416	if (!value)
	417	goto set_acl;
	418
	419	acl = posix_acl_from_xattr(value, size);
	420	if (!acl) {
421	/*
422	* acl_set_file(3) may request that we set default ACLs with
423	* zero length -- defend (gracefully) against that here.
424	*/
425	goto out;
426	}
427	if (IS_ERR(acl)) {
428	error = PTR_ERR(acl);
429	goto out;
430	}
431
432	error = posix_acl_valid(acl);
433	if (error)
434	goto out_release;
435
436	error = -EINVAL;
437	if (acl->a_count > XFS_ACL_MAX_ENTRIES)
438	goto out_release;
439
440	if (type == ACL_TYPE_ACCESS) {
441	mode_t mode = inode->i_mode;
442	error = posix_acl_equiv_mode(acl, &mode);
443
444	if (error <= 0) {
445	posix_acl_release(acl);
446	acl = NULL;
447
448	if (error < 0)
449	return error;
450	}
451
452	error = xfs_set_mode(inode, mode);
453	if (error)
454	goto out_release;
455	}
456
457	set_acl:
458	error = xfs_set_acl(inode, type, acl);
459	out_release:
460	posix_acl_release(acl);
461	out:
462	return error;
463	}
464
465	struct xattr_handler xfs_xattr_system_handler = {
466	.prefix = XATTR_SYSTEM_PREFIX,
467	.get = xfs_xattr_system_get,
468	.set = xfs_xattr_system_set,
469	};