[mirror_ubuntu-artful-kernel.git] / fs / ext2 / acl.c

/*
 * linux/fs/ext2/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext2_acl_from_disk(const void *value, size_t size)
{
	const char *end = (char *)value + size;
	int n, count;
	struct posix_acl *acl;

	if (!value)
		return NULL;
	if (size < sizeof(ext2_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext2_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT2_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext2_acl_header);
	count = ext2_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n=0; n < count; n++) {
		ext2_acl_entry *entry =
			(ext2_acl_entry *)value;
		if ((char *)value + sizeof(ext2_acl_entry_short) > end)
			goto fail;
		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
		switch(acl->a_entries[n].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value = (char *)value +
					sizeof(ext2_acl_entry_short);
				break;

			case ACL_USER:
				value = (char *)value + sizeof(ext2_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_uid =
					make_kuid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value = (char *)value + sizeof(ext2_acl_entry);
				if ((char *)value > end)
					goto fail;
				acl->a_entries[n].e_gid =
					make_kgid(&init_user_ns,
						  le32_to_cpu(entry->e_id));
				break;

			default:
				goto fail;
		}
	}
	if (value != end)
		goto fail;
	return acl;

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

/*
 * Convert from in-memory to filesystem representation.
 */
static void *
ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext2_acl_header *ext_acl;
	char *e;
	size_t n;

	*size = ext2_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
			sizeof(ext2_acl_entry), GFP_KERNEL);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext2_acl_header);
	for (n=0; n < acl->a_count; n++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext2_acl_entry *entry = (ext2_acl_entry *)e;
		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
		entry->e_perm = cpu_to_le16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_le32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(ext2_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_le32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				e += sizeof(ext2_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(ext2_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return (char *)ext_acl;

fail:
	kfree(ext_acl);
	return ERR_PTR(-EINVAL);
}

/*
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext2_get_acl(struct inode *inode, int type)
{
	int name_index;
	char *value = NULL;
	struct posix_acl *acl;
	int retval;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext2_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext2_acl_from_disk(value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	return acl;
}

static int
__ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	switch(type) {
		case ACL_TYPE_ACCESS:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
			break;

		case ACL_TYPE_DEFAULT:
			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
			if (!S_ISDIR(inode->i_mode))
				return acl ? -EACCES : 0;
			break;

		default:
			return -EINVAL;
	}
 	if (acl) {
		value = ext2_acl_to_disk(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext2_xattr_set(inode, name_index, "", value, size, 0);

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

/*
 * inode->i_mutex: down
 */
int
ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int error;
	int update_mode = 0;
	umode_t mode = inode->i_mode;

	if (type == ACL_TYPE_ACCESS && acl) {
		error = posix_acl_update_mode(inode, &mode, &acl);
		if (error)
			return error;
		update_mode = 1;
	}
	error = __ext2_set_acl(inode, acl, type);
	if (!error && update_mode) {
		inode->i_mode = mode;
		inode->i_ctime = current_time(inode);
		mark_inode_dirty(inode);
	}
	return error;
}

/*
 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext2_init_acl(struct inode *inode, struct inode *dir)
{
	struct posix_acl *default_acl, *acl;
	int error;

	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	if (error)
		return error;

	if (default_acl) {
		error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
		posix_acl_release(default_acl);
	}
	if (acl) {
		if (!error)
			error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
		posix_acl_release(acl);
	}
	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext2/acl.c
	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
	10	#include <linux/fs.h>
	11	#include "ext2.h"
	12	#include "xattr.h"
	13	#include "acl.h"
	14
	15	/*
	16	* Convert from filesystem to in-memory representation.
	17	*/
	18	static struct posix_acl *
	19	ext2_acl_from_disk(const void *value, size_t size)
	20	{
	21	const char end = (char )value + size;
	22	int n, count;
	23	struct posix_acl *acl;
	24
	25	if (!value)
	26	return NULL;
	27	if (size < sizeof(ext2_acl_header))
	28	return ERR_PTR(-EINVAL);
	29	if (((ext2_acl_header *)value)->a_version !=
	30	cpu_to_le32(EXT2_ACL_VERSION))
	31	return ERR_PTR(-EINVAL);
	32	value = (char *)value + sizeof(ext2_acl_header);
	33	count = ext2_acl_count(size);
	34	if (count < 0)
	35	return ERR_PTR(-EINVAL);
	36	if (count == 0)
	37	return NULL;
	38	acl = posix_acl_alloc(count, GFP_KERNEL);
	39	if (!acl)
	40	return ERR_PTR(-ENOMEM);
	41	for (n=0; n < count; n++) {
	42	ext2_acl_entry *entry =
	43	(ext2_acl_entry *)value;
	44	if ((char *)value + sizeof(ext2_acl_entry_short) > end)
	45	goto fail;
	46	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	47	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
	48	switch(acl->a_entries[n].e_tag) {
	49	case ACL_USER_OBJ:
	50	case ACL_GROUP_OBJ:
	51	case ACL_MASK:
	52	case ACL_OTHER:
	53	value = (char *)value +
	54	sizeof(ext2_acl_entry_short);
1da177e4 LT	55	break;
	56
	57	case ACL_USER:
af84df93 EB	58	value = (char *)value + sizeof(ext2_acl_entry);
	59	if ((char *)value > end)
	60	goto fail;
	61	acl->a_entries[n].e_uid =
	62	make_kuid(&init_user_ns,
	63	le32_to_cpu(entry->e_id));
	64	break;
1da177e4 LT	65	case ACL_GROUP:
	66	value = (char *)value + sizeof(ext2_acl_entry);
	67	if ((char *)value > end)
	68	goto fail;
af84df93 EB	69	acl->a_entries[n].e_gid =
	70	make_kgid(&init_user_ns,
	71	le32_to_cpu(entry->e_id));
1da177e4 LT	72	break;
	73
	74	default:
	75	goto fail;
	76	}
	77	}
	78	if (value != end)
	79	goto fail;
	80	return acl;
	81
	82	fail:
	83	posix_acl_release(acl);
	84	return ERR_PTR(-EINVAL);
	85	}
	86
	87	/*
	88	* Convert from in-memory to filesystem representation.
	89	*/
	90	static void *
	91	ext2_acl_to_disk(const struct posix_acl acl, size_t size)
	92	{
	93	ext2_acl_header *ext_acl;
	94	char *e;
	95	size_t n;
	96
	97	*size = ext2_acl_size(acl->a_count);
f52720ca PI	98	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
f52720ca PI	99	sizeof(ext2_acl_entry), GFP_KERNEL);
1da177e4 LT	100	if (!ext_acl)
	101	return ERR_PTR(-ENOMEM);
	102	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
	103	e = (char *)ext_acl + sizeof(ext2_acl_header);
	104	for (n=0; n < acl->a_count; n++) {
af84df93	105	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
1da177e4	106	ext2_acl_entry entry = (ext2_acl_entry )e;
af84df93 EB	107	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	108	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	109	switch(acl_e->e_tag) {
1da177e4	110	case ACL_USER:
af84df93 EB	111	entry->e_id = cpu_to_le32(
	112	from_kuid(&init_user_ns, acl_e->e_uid));
	113	e += sizeof(ext2_acl_entry);
	114	break;
1da177e4	115	case ACL_GROUP:
af84df93 EB	116	entry->e_id = cpu_to_le32(
af84df93 EB	117	from_kgid(&init_user_ns, acl_e->e_gid));
1da177e4 LT	118	e += sizeof(ext2_acl_entry);
	119	break;
	120
	121	case ACL_USER_OBJ:
	122	case ACL_GROUP_OBJ:
	123	case ACL_MASK:
	124	case ACL_OTHER:
	125	e += sizeof(ext2_acl_entry_short);
	126	break;
	127
	128	default:
	129	goto fail;
	130	}
	131	}
	132	return (char *)ext_acl;
	133
	134	fail:
	135	kfree(ext_acl);
	136	return ERR_PTR(-EINVAL);
	137	}
	138
1da177e4	139	/*
1b1dcc1b	140	* inode->i_mutex: don't care
1da177e4	141	*/
4e34e719	142	struct posix_acl *
1da177e4 LT	143	ext2_get_acl(struct inode *inode, int type)
1da177e4 LT	144	{
1da177e4 LT	145	int name_index;
	146	char *value = NULL;
	147	struct posix_acl *acl;
	148	int retval;
	149
073aaa1b AV	150	switch (type) {
	151	case ACL_TYPE_ACCESS:
	152	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
	153	break;
	154	case ACL_TYPE_DEFAULT:
	155	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	156	break;
	157	default:
	158	BUG();
1da177e4 LT	159	}
	160	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
	161	if (retval > 0) {
	162	value = kmalloc(retval, GFP_KERNEL);
	163	if (!value)
	164	return ERR_PTR(-ENOMEM);
	165	retval = ext2_xattr_get(inode, name_index, "", value, retval);
	166	}
	167	if (retval > 0)
	168	acl = ext2_acl_from_disk(value, retval);
	169	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	170	acl = NULL;
	171	else
	172	acl = ERR_PTR(retval);
f99d49ad	173	kfree(value);
1da177e4	174
1da177e4 LT	175	return acl;
	176	}
	177
a992f2d3 JK	178	static int
a992f2d3 JK	179	__ext2_set_acl(struct inode inode, struct posix_acl acl, int type)
1da177e4	180	{
1da177e4 LT	181	int name_index;
1da177e4 LT	182	void *value = NULL;
dfa08592	183	size_t size = 0;
1da177e4 LT	184	int error;
1da177e4 LT	185
1da177e4 LT	186	switch(type) {
	187	case ACL_TYPE_ACCESS:
	188	name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
1da177e4 LT	189	break;
	190
	191	case ACL_TYPE_DEFAULT:
	192	name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
	193	if (!S_ISDIR(inode->i_mode))
	194	return acl ? -EACCES : 0;
	195	break;
	196
	197	default:
	198	return -EINVAL;
	199	}
	200	if (acl) {
	201	value = ext2_acl_to_disk(acl, &size);
	202	if (IS_ERR(value))
	203	return (int)PTR_ERR(value);
	204	}
	205
	206	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
	207
f99d49ad	208	kfree(value);
073aaa1b AV	209	if (!error)
073aaa1b AV	210	set_cached_acl(inode, type, acl);
1da177e4 LT	211	return error;
	212	}
	213
a992f2d3 JK	214	/*
	215	* inode->i_mutex: down
	216	*/
	217	int
	218	ext2_set_acl(struct inode inode, struct posix_acl acl, int type)
	219	{
	220	int error;
fe26569e EF	221	int update_mode = 0;
fe26569e EF	222	umode_t mode = inode->i_mode;
a992f2d3 JK	223
a992f2d3 JK	224	if (type == ACL_TYPE_ACCESS && acl) {
fe26569e	225	error = posix_acl_update_mode(inode, &mode, &acl);
a992f2d3 JK	226	if (error)
a992f2d3 JK	227	return error;
fe26569e EF	228	update_mode = 1;
	229	}
	230	error = __ext2_set_acl(inode, acl, type);
	231	if (!error && update_mode) {
	232	inode->i_mode = mode;
a992f2d3 JK	233	inode->i_ctime = current_time(inode);
	234	mark_inode_dirty(inode);
	235	}
fe26569e	236	return error;
a992f2d3 JK	237	}
a992f2d3 JK	238
1da177e4 LT	239	/*
	240	* Initialize the ACLs of a new inode. Called from ext2_new_inode.
	241	*
1b1dcc1b JS	242	* dir->i_mutex: down
1b1dcc1b JS	243	* inode->i_mutex: up (access to inode is still exclusive)
1da177e4 LT	244	*/
	245	int
	246	ext2_init_acl(struct inode inode, struct inode dir)
	247	{
64e178a7 CH	248	struct posix_acl default_acl, acl;
64e178a7 CH	249	int error;
1da177e4	250
64e178a7	251	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
bc26ab5f AV	252	if (error)
bc26ab5f AV	253	return error;
1da177e4	254
64e178a7	255	if (default_acl) {
a992f2d3	256	error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
64e178a7 CH	257	posix_acl_release(default_acl);
	258	}
	259	if (acl) {
	260	if (!error)
a992f2d3	261	error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
64e178a7 CH	262	posix_acl_release(acl);
64e178a7 CH	263	}
1da177e4 LT	264	return error;
1da177e4 LT	265	}