[mirror_ubuntu-artful-kernel.git] / fs / ext4 / acl.c

/*
 * linux/fs/ext4/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/quotaops.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
#include "acl.h"

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *
ext4_acl_from_disk(struct super_block *sb, 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(ext4_acl_header))
		 return ERR_PTR(-EINVAL);
	if (((ext4_acl_header *)value)->a_version !=
	    cpu_to_le32(EXT4_ACL_VERSION))
		return ERR_PTR(-EINVAL);
	value = (char *)value + sizeof(ext4_acl_header);
	count = ext4_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	acl = posix_acl_alloc(count, GFP_NOFS);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	for (n = 0; n < count; n++) {
		ext4_acl_entry *entry =
			(ext4_acl_entry *)value;
		if ((char *)value + sizeof(ext4_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(ext4_acl_entry_short);
			break;

		case ACL_USER:
			value = (char *)value + sizeof(ext4_acl_entry);
			if ((char *)value > end)
				goto fail;
			acl->a_entries[n].e_uid =
				make_kuid(sb->s_user_ns,
					  le32_to_cpu(entry->e_id));
			if (!uid_valid(acl->a_entries[n].e_uid))
				goto fail;
			break;
		case ACL_GROUP:
			value = (char *)value + sizeof(ext4_acl_entry);
			if ((char *)value > end)
				goto fail;
			acl->a_entries[n].e_gid =
				make_kgid(sb->s_user_ns,
					  le32_to_cpu(entry->e_id));
			if (!gid_valid(acl->a_entries[n].e_gid))
				goto fail;
			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 *
ext4_acl_to_disk(struct super_block *sb, const struct posix_acl *acl,
		 size_t *size)
{
	ext4_acl_header *ext_acl;
	char *e;
	size_t n;
	uid_t uid;
	gid_t gid;

	*size = ext4_acl_size(acl->a_count);
	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
			sizeof(ext4_acl_entry), GFP_NOFS);
	if (!ext_acl)
		return ERR_PTR(-ENOMEM);
	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
	e = (char *)ext_acl + sizeof(ext4_acl_header);
	for (n = 0; n < acl->a_count; n++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
		ext4_acl_entry *entry = (ext4_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:
			uid = from_kuid(sb->s_user_ns, acl_e->e_uid);
			if (uid == (uid_t)-1)
				goto fail;
			entry->e_id = cpu_to_le32(uid);
			e += sizeof(ext4_acl_entry);
			break;
		case ACL_GROUP:
			gid = from_kgid(sb->s_user_ns, acl_e->e_gid);
			if (gid == (gid_t)-1)
				goto fail;
			entry->e_id = cpu_to_le32(gid);
			e += sizeof(ext4_acl_entry);
			break;

		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			e += sizeof(ext4_acl_entry_short);
			break;

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

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

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: don't care
 */
struct posix_acl *
ext4_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 = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
	if (retval > 0) {
		value = kmalloc(retval, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		retval = ext4_xattr_get(inode, name_index, "", value, retval);
	}
	if (retval > 0)
		acl = ext4_acl_from_disk(inode->i_sb, value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	return acl;
}

/*
 * Set the access or default ACL of an inode.
 *
 * inode->i_mutex: down unless called from ext4_new_inode
 */
static int
__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
	     struct posix_acl *acl, int xattr_flags)
{
	int name_index;
	void *value = NULL;
	size_t size = 0;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;

	case ACL_TYPE_DEFAULT:
		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		break;

	default:
		return -EINVAL;
	}
	if (acl) {
		value = ext4_acl_to_disk(inode->i_sb, acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext4_xattr_set_handle(handle, inode, name_index, "",
				      value, size, xattr_flags);

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

	return error;
}

int
ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	handle_t *handle;
	int error, credits, retries = 0;
	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
	umode_t mode = inode->i_mode;
	int update_mode = 0;

	error = dquot_initialize(inode);
	if (error)
		return error;
retry:
	error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
				       &credits);
	if (error)
		return error;

	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
	if (IS_ERR(handle))
		return PTR_ERR(handle);

	if ((type == ACL_TYPE_ACCESS) && acl) {
		error = posix_acl_update_mode(inode, &mode, &acl);
		if (error)
			goto out_stop;
		update_mode = 1;
	}

	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
	if (!error && update_mode) {
		inode->i_mode = mode;
		inode->i_ctime = current_time(inode);
		ext4_mark_inode_dirty(handle, inode);
	}
out_stop:
	ext4_journal_stop(handle);
	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
	return error;
}

/*
 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
 *
 * dir->i_mutex: down
 * inode->i_mutex: up (access to inode is still exclusive)
 */
int
ext4_init_acl(handle_t *handle, 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 = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
				       default_acl, XATTR_CREATE);
		posix_acl_release(default_acl);
	}
	if (acl) {
		if (!error)
			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
					       acl, XATTR_CREATE);
		posix_acl_release(acl);
	}
	return error;
}
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	* linux/fs/ext4/acl.c
ac27a0ec DK	3	*
	4	* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
	5	*/
	6
b8cb5a54	7	#include <linux/quotaops.h>
3dcf5451 CH	8	#include "ext4_jbd2.h"
3dcf5451 CH	9	#include "ext4.h"
ac27a0ec DK	10	#include "xattr.h"
	11	#include "acl.h"
	12
	13	/*
	14	* Convert from filesystem to in-memory representation.
	15	*/
	16	static struct posix_acl *
afdbd4a6	17	ext4_acl_from_disk(struct super_block sb, const void value, size_t size)
ac27a0ec DK	18	{
	19	const char end = (char )value + size;
	20	int n, count;
	21	struct posix_acl *acl;
	22
	23	if (!value)
	24	return NULL;
617ba13b	25	if (size < sizeof(ext4_acl_header))
ac27a0ec	26	return ERR_PTR(-EINVAL);
617ba13b MC	27	if (((ext4_acl_header *)value)->a_version !=
617ba13b MC	28	cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec	29	return ERR_PTR(-EINVAL);
617ba13b MC	30	value = (char *)value + sizeof(ext4_acl_header);
617ba13b MC	31	count = ext4_acl_count(size);
ac27a0ec DK	32	if (count < 0)
	33	return ERR_PTR(-EINVAL);
	34	if (count == 0)
	35	return NULL;
216553c4	36	acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec DK	37	if (!acl)
ac27a0ec DK	38	return ERR_PTR(-ENOMEM);
2b2d6d01	39	for (n = 0; n < count; n++) {
617ba13b MC	40	ext4_acl_entry *entry =
	41	(ext4_acl_entry *)value;
	42	if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec DK	43	goto fail;
	44	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	45	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
2b2d6d01 TT	46
	47	switch (acl->a_entries[n].e_tag) {
	48	case ACL_USER_OBJ:
	49	case ACL_GROUP_OBJ:
	50	case ACL_MASK:
	51	case ACL_OTHER:
	52	value = (char *)value +
	53	sizeof(ext4_acl_entry_short);
2b2d6d01 TT	54	break;
	55
	56	case ACL_USER:
af84df93 EB	57	value = (char *)value + sizeof(ext4_acl_entry);
	58	if ((char *)value > end)
	59	goto fail;
	60	acl->a_entries[n].e_uid =
afdbd4a6	61	make_kuid(sb->s_user_ns,
af84df93	62	le32_to_cpu(entry->e_id));
afdbd4a6 SF	63	if (!uid_valid(acl->a_entries[n].e_uid))
afdbd4a6 SF	64	goto fail;
af84df93	65	break;
2b2d6d01 TT	66	case ACL_GROUP:
	67	value = (char *)value + sizeof(ext4_acl_entry);
	68	if ((char *)value > end)
ac27a0ec	69	goto fail;
af84df93	70	acl->a_entries[n].e_gid =
afdbd4a6	71	make_kgid(sb->s_user_ns,
af84df93	72	le32_to_cpu(entry->e_id));
afdbd4a6 SF	73	if (!gid_valid(acl->a_entries[n].e_gid))
afdbd4a6 SF	74	goto fail;
2b2d6d01 TT	75	break;
	76
	77	default:
	78	goto fail;
ac27a0ec DK	79	}
	80	}
	81	if (value != end)
	82	goto fail;
	83	return acl;
	84
	85	fail:
	86	posix_acl_release(acl);
	87	return ERR_PTR(-EINVAL);
	88	}
	89
	90	/*
	91	* Convert from in-memory to filesystem representation.
	92	*/
	93	static void *
afdbd4a6 SF	94	ext4_acl_to_disk(struct super_block sb, const struct posix_acl acl,
afdbd4a6 SF	95	size_t *size)
ac27a0ec	96	{
617ba13b	97	ext4_acl_header *ext_acl;
ac27a0ec DK	98	char *e;
ac27a0ec DK	99	size_t n;
afdbd4a6 SF	100	uid_t uid;
afdbd4a6 SF	101	gid_t gid;
ac27a0ec	102
617ba13b MC	103	*size = ext4_acl_size(acl->a_count);
617ba13b MC	104	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	105	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	106	if (!ext_acl)
ac27a0ec DK	107	return ERR_PTR(-ENOMEM);
617ba13b MC	108	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	109	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	110	for (n = 0; n < acl->a_count; n++) {
af84df93	111	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
617ba13b	112	ext4_acl_entry entry = (ext4_acl_entry )e;
af84df93 EB	113	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	114	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	115	switch (acl_e->e_tag) {
2b2d6d01	116	case ACL_USER:
afdbd4a6 SF	117	uid = from_kuid(sb->s_user_ns, acl_e->e_uid);
	118	if (uid == (uid_t)-1)
	119	goto fail;
	120	entry->e_id = cpu_to_le32(uid);
af84df93 EB	121	e += sizeof(ext4_acl_entry);
af84df93 EB	122	break;
2b2d6d01	123	case ACL_GROUP:
afdbd4a6 SF	124	gid = from_kgid(sb->s_user_ns, acl_e->e_gid);
	125	if (gid == (gid_t)-1)
	126	goto fail;
	127	entry->e_id = cpu_to_le32(gid);
2b2d6d01 TT	128	e += sizeof(ext4_acl_entry);
	129	break;
	130
	131	case ACL_USER_OBJ:
	132	case ACL_GROUP_OBJ:
	133	case ACL_MASK:
	134	case ACL_OTHER:
	135	e += sizeof(ext4_acl_entry_short);
	136	break;
	137
	138	default:
	139	goto fail;
ac27a0ec DK	140	}
	141	}
	142	return (char *)ext_acl;
	143
	144	fail:
	145	kfree(ext_acl);
	146	return ERR_PTR(-EINVAL);
	147	}
	148
ac27a0ec DK	149	/*
	150	* Inode operation get_posix_acl().
	151	*
	152	* inode->i_mutex: don't care
	153	*/
4e34e719	154	struct posix_acl *
617ba13b	155	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	156	{
ac27a0ec DK	157	int name_index;
	158	char *value = NULL;
	159	struct posix_acl *acl;
	160	int retval;
	161
2b2d6d01 TT	162	switch (type) {
2b2d6d01 TT	163	case ACL_TYPE_ACCESS:
2b2d6d01 TT	164	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	165	break;
2b2d6d01	166	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	167	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	168	break;
2b2d6d01	169	default:
073aaa1b	170	BUG();
ac27a0ec	171	}
617ba13b	172	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	173	if (retval > 0) {
216553c4	174	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	175	if (!value)
ac27a0ec DK	176	return ERR_PTR(-ENOMEM);
617ba13b	177	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	178	}
ac27a0ec DK	179	if (retval > 0)
afdbd4a6	180	acl = ext4_acl_from_disk(inode->i_sb, value, retval);
ac27a0ec DK	181	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	182	acl = NULL;
	183	else
	184	acl = ERR_PTR(retval);
	185	kfree(value);
	186
ac27a0ec DK	187	return acl;
	188	}
	189
	190	/*
	191	* Set the access or default ACL of an inode.
	192	*
617ba13b	193	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	194	*/
ac27a0ec DK	195	static int
64e178a7	196	__ext4_set_acl(handle_t handle, struct inode inode, int type,
af65207c	197	struct posix_acl *acl, int xattr_flags)
ac27a0ec	198	{
ac27a0ec DK	199	int name_index;
	200	void *value = NULL;
	201	size_t size = 0;
	202	int error;
	203
2b2d6d01 TT	204	switch (type) {
	205	case ACL_TYPE_ACCESS:
	206	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01	207	break;
ac27a0ec	208
2b2d6d01 TT	209	case ACL_TYPE_DEFAULT:
	210	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	211	if (!S_ISDIR(inode->i_mode))
	212	return acl ? -EACCES : 0;
	213	break;
ac27a0ec	214
2b2d6d01 TT	215	default:
2b2d6d01 TT	216	return -EINVAL;
ac27a0ec DK	217	}
ac27a0ec DK	218	if (acl) {
afdbd4a6	219	value = ext4_acl_to_disk(inode->i_sb, acl, &size);
ac27a0ec DK	220	if (IS_ERR(value))
	221	return (int)PTR_ERR(value);
	222	}
	223
617ba13b	224	error = ext4_xattr_set_handle(handle, inode, name_index, "",
af65207c	225	value, size, xattr_flags);
ac27a0ec DK	226
ac27a0ec DK	227	kfree(value);
397e4341	228	if (!error) {
073aaa1b	229	set_cached_acl(inode, type, acl);
397e4341	230	}
2b2d6d01	231
ac27a0ec DK	232	return error;
	233	}
	234
ac27a0ec	235	int
64e178a7	236	ext4_set_acl(struct inode inode, struct posix_acl acl, int type)
ac27a0ec	237	{
bc26ab5f	238	handle_t *handle;
c1a5d5f6 TE	239	int error, credits, retries = 0;
c1a5d5f6 TE	240	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
a3bb2d55 JK	241	umode_t mode = inode->i_mode;
a3bb2d55 JK	242	int update_mode = 0;
bc26ab5f	243
b8cb5a54 TE	244	error = dquot_initialize(inode);
	245	if (error)
	246	return error;
bc26ab5f	247	retry:
af65207c TE	248	error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
af65207c TE	249	&credits);
dec214d0 TE	250	if (error)
	251	return error;
	252
c1a5d5f6	253	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
64e178a7 CH	254	if (IS_ERR(handle))
	255	return PTR_ERR(handle);
	256
a3bb2d55 JK	257	if ((type == ACL_TYPE_ACCESS) && acl) {
	258	error = posix_acl_update_mode(inode, &mode, &acl);
	259	if (error)
	260	goto out_stop;
	261	update_mode = 1;
	262	}
	263
af65207c	264	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
a3bb2d55 JK	265	if (!error && update_mode) {
	266	inode->i_mode = mode;
	267	inode->i_ctime = current_time(inode);
	268	ext4_mark_inode_dirty(handle, inode);
	269	}
	270	out_stop:
bc26ab5f	271	ext4_journal_stop(handle);
64e178a7	272	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	273	goto retry;
ac27a0ec DK	274	return error;
	275	}
	276
	277	/*
64e178a7 CH	278	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
	279	*
	280	* dir->i_mutex: down
	281	* inode->i_mutex: up (access to inode is still exclusive)
ac27a0ec	282	*/
64e178a7 CH	283	int
64e178a7 CH	284	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec	285	{
64e178a7	286	struct posix_acl default_acl, acl;
ac27a0ec DK	287	int error;
ac27a0ec DK	288
64e178a7 CH	289	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	290	if (error)
	291	return error;
ac27a0ec	292
64e178a7 CH	293	if (default_acl) {
64e178a7 CH	294	error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
af65207c	295	default_acl, XATTR_CREATE);
64e178a7 CH	296	posix_acl_release(default_acl);
	297	}
	298	if (acl) {
	299	if (!error)
	300	error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
af65207c	301	acl, XATTR_CREATE);
64e178a7	302	posix_acl_release(acl);
24ec19b0	303	}
ac27a0ec DK	304	return error;
ac27a0ec DK	305	}