[mirror_ubuntu-artful-kernel.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_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(
	const struct xfs_acl	*aclp,
	int			len,
	int			max_entries)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	const struct xfs_acl_entry *ace;
	unsigned int count, i;

	if (len < sizeof(*aclp))
		return ERR_PTR(-EFSCORRUPTED);
	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries || XFS_ACL_SIZE(count) != len)
		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;
		acl = ERR_PTR(error);
		goto out;
	}

	acl = xfs_acl_from_disk(xfs_acl, len, 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"
0a8aa193	22	#include "xfs_mount.h"
a4fbe6ab DC	23	#include "xfs_inode.h"
	24	#include "xfs_acl.h"
	25	#include "xfs_attr.h"
0b1b213f	26	#include "xfs_trace.h"
5a0e3ad6	27	#include <linux/slab.h>
ef14f0c1 CH	28	#include <linux/xattr.h>
	29	#include <linux/posix_acl_xattr.h>
	30
	31
ef14f0c1 CH	32	/*
	33	* Locking scheme:
	34	* - all ACL updates are protected by inode->i_mutex, which is taken before
	35	* calling into this file.
ef14f0c1 CH	36	*/
	37
	38	STATIC struct posix_acl *
0a8aa193	39	xfs_acl_from_disk(
86a21c79 AG	40	const struct xfs_acl *aclp,
	41	int len,
	42	int max_entries)
ef14f0c1 CH	43	{
	44	struct posix_acl_entry *acl_e;
	45	struct posix_acl *acl;
86a21c79	46	const struct xfs_acl_entry *ace;
093019cf	47	unsigned int count, i;
ef14f0c1	48
86a21c79 AG	49	if (len < sizeof(*aclp))
86a21c79 AG	50	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1	51	count = be32_to_cpu(aclp->acl_cnt);
86a21c79	52	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len)
fa8b18ed	53	return ERR_PTR(-EFSCORRUPTED);
ef14f0c1 CH	54
	55	acl = posix_acl_alloc(count, GFP_KERNEL);
	56	if (!acl)
	57	return ERR_PTR(-ENOMEM);
	58
	59	for (i = 0; i < count; i++) {
	60	acl_e = &acl->a_entries[i];
	61	ace = &aclp->acl_entry[i];
	62
	63	/*
	64	* The tag is 32 bits on disk and 16 bits in core.
	65	*
	66	* Because every access to it goes through the core
	67	* format first this is not a problem.
	68	*/
	69	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	70	acl_e->e_perm = be16_to_cpu(ace->ae_perm);
	71
	72	switch (acl_e->e_tag) {
	73	case ACL_USER:
288bbe0e DE	74	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
288bbe0e DE	75	break;
ef14f0c1	76	case ACL_GROUP:
288bbe0e	77	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
ef14f0c1 CH	78	break;
	79	case ACL_USER_OBJ:
	80	case ACL_GROUP_OBJ:
	81	case ACL_MASK:
	82	case ACL_OTHER:
ef14f0c1 CH	83	break;
	84	default:
	85	goto fail;
	86	}
	87	}
	88	return acl;
	89
	90	fail:
	91	posix_acl_release(acl);
	92	return ERR_PTR(-EINVAL);
	93	}
	94
	95	STATIC void
	96	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	97	{
	98	const struct posix_acl_entry *acl_e;
	99	struct xfs_acl_entry *ace;
	100	int i;
	101
	102	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	103	for (i = 0; i < acl->a_count; i++) {
	104	ace = &aclp->acl_entry[i];
	105	acl_e = &acl->a_entries[i];
	106
	107	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
288bbe0e DE	108	switch (acl_e->e_tag) {
	109	case ACL_USER:
	110	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	111	break;
	112	case ACL_GROUP:
	113	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	114	break;
	115	default:
	116	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	117	break;
	118	}
	119
ef14f0c1 CH	120	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	121	}
	122	}
	123
ef14f0c1 CH	124	struct posix_acl *
	125	xfs_get_acl(struct inode *inode, int type)
	126	{
	127	struct xfs_inode *ip = XFS_I(inode);
2401dc29	128	struct posix_acl *acl = NULL;
ef14f0c1	129	struct xfs_acl *xfs_acl;
a9273ca5	130	unsigned char *ea_name;
ef14f0c1	131	int error;
0a8aa193	132	int len;
ef14f0c1	133
4e34e719 CH	134	trace_xfs_get_acl(ip);
4e34e719 CH	135
ef14f0c1 CH	136	switch (type) {
	137	case ACL_TYPE_ACCESS:
	138	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	139	break;
	140	case ACL_TYPE_DEFAULT:
	141	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	142	break;
ef14f0c1 CH	143	default:
1cbd20d8	144	BUG();
ef14f0c1 CH	145	}
ef14f0c1 CH	146
ef14f0c1 CH	147	/*
	148	* If we have a cached ACLs value just return it, not need to
	149	* go out to the disk.
	150	*/
0a8aa193	151	len = XFS_ACL_MAX_SIZE(ip->i_mount);
fdd3ccee DC	152	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	153	if (!xfs_acl)
	154	return ERR_PTR(-ENOMEM);
ef14f0c1	155
2451337d	156	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
a9273ca5	157	&len, ATTR_ROOT);
ef14f0c1 CH	158	if (error) {
	159	/*
	160	* If the attribute doesn't exist make sure we have a negative
	161	* cache entry, for any other error assume it is transient and
1cbd20d8	162	* leave the cache entry as ACL_NOT_CACHED.
ef14f0c1	163	*/
2401dc29	164	if (error == -ENOATTR)
ef14f0c1	165	goto out_update_cache;
edfb8ebc	166	acl = ERR_PTR(error);
ef14f0c1 CH	167	goto out;
	168	}
	169
86a21c79	170	acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount));
ef14f0c1 CH	171	if (IS_ERR(acl))
	172	goto out;
	173
2dc164f2	174	out_update_cache:
1cbd20d8	175	set_cached_acl(inode, type, acl);
2dc164f2	176	out:
fdd3ccee	177	kmem_free(xfs_acl);
ef14f0c1 CH	178	return acl;
	179	}
	180
	181	STATIC int
2401dc29	182	__xfs_set_acl(struct inode inode, int type, struct posix_acl acl)
ef14f0c1 CH	183	{
ef14f0c1 CH	184	struct xfs_inode *ip = XFS_I(inode);
a9273ca5	185	unsigned char *ea_name;
ef14f0c1 CH	186	int error;
ef14f0c1 CH	187
ef14f0c1 CH	188	switch (type) {
	189	case ACL_TYPE_ACCESS:
	190	ea_name = SGI_ACL_FILE;
ef14f0c1 CH	191	break;
	192	case ACL_TYPE_DEFAULT:
	193	if (!S_ISDIR(inode->i_mode))
	194	return acl ? -EACCES : 0;
	195	ea_name = SGI_ACL_DEFAULT;
ef14f0c1 CH	196	break;
	197	default:
	198	return -EINVAL;
	199	}
	200
	201	if (acl) {
	202	struct xfs_acl *xfs_acl;
0a8aa193	203	int len = XFS_ACL_MAX_SIZE(ip->i_mount);
ef14f0c1	204
fdd3ccee DC	205	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	206	if (!xfs_acl)
	207	return -ENOMEM;
ef14f0c1 CH	208
ef14f0c1 CH	209	xfs_acl_to_disk(xfs_acl, acl);
0a8aa193 DC	210
	211	/* subtract away the unused acl entries */
	212	len -= sizeof(struct xfs_acl_entry) *
	213	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
ef14f0c1	214
2451337d	215	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
ef14f0c1 CH	216	len, ATTR_ROOT);
ef14f0c1 CH	217
fdd3ccee	218	kmem_free(xfs_acl);
ef14f0c1 CH	219	} else {
	220	/*
	221	* A NULL ACL argument means we want to remove the ACL.
	222	*/
2451337d	223	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
ef14f0c1 CH	224
	225	/*
	226	* If the attribute didn't exist to start with that's fine.
	227	*/
	228	if (error == -ENOATTR)
	229	error = 0;
	230	}
	231
	232	if (!error)
1cbd20d8	233	set_cached_acl(inode, type, acl);
ef14f0c1 CH	234	return error;
	235	}
	236
ef14f0c1	237	static int
d3fb6120	238	xfs_set_mode(struct inode *inode, umode_t mode)
ef14f0c1 CH	239	{
	240	int error = 0;
	241
	242	if (mode != inode->i_mode) {
	243	struct iattr iattr;
	244
d6d59bad	245	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
ef14f0c1	246	iattr.ia_mode = mode;
d6d59bad	247	iattr.ia_ctime = current_fs_time(inode->i_sb);
ef14f0c1	248
2451337d	249	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
ef14f0c1 CH	250	}
	251
	252	return error;
	253	}
	254
	255	static int
a9273ca5	256	xfs_acl_exists(struct inode inode, unsigned char name)
ef14f0c1	257	{
0a8aa193	258	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));
ef14f0c1 CH	259
	260	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
	261	ATTR_ROOT\|ATTR_KERNOVAL) == 0);
	262	}
	263
	264	int
	265	posix_acl_access_exists(struct inode *inode)
	266	{
	267	return xfs_acl_exists(inode, SGI_ACL_FILE);
	268	}
	269
	270	int
	271	posix_acl_default_exists(struct inode *inode)
	272	{
	273	if (!S_ISDIR(inode->i_mode))
	274	return 0;
	275	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
	276	}
	277
ef14f0c1	278	int
2401dc29	279	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
ef14f0c1	280	{
431547b3	281	int error = 0;
ef14f0c1	282
2401dc29	283	if (!acl)
ef14f0c1 CH	284	goto set_acl;
ef14f0c1 CH	285
4ae69fea	286	error = -E2BIG;
0a8aa193	287	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
2401dc29	288	return error;
ef14f0c1 CH	289
ef14f0c1 CH	290	if (type == ACL_TYPE_ACCESS) {
d6952123	291	umode_t mode = inode->i_mode;
ef14f0c1 CH	292	error = posix_acl_equiv_mode(acl, &mode);
	293
	294	if (error <= 0) {
ef14f0c1 CH	295	acl = NULL;
	296
	297	if (error < 0)
	298	return error;
	299	}
	300
	301	error = xfs_set_mode(inode, mode);
	302	if (error)
2401dc29	303	return error;
ef14f0c1 CH	304	}
	305
	306	set_acl:
2401dc29	307	return __xfs_set_acl(inode, type, acl);
ef14f0c1	308	}