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

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

#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(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(&init_user_ns,
					  le32_to_cpu(entry->e_id));
			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(&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 *
ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
	ext4_acl_header *ext_acl;
	char *e;
	size_t n;

	*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:
			entry->e_id = cpu_to_le32(
				from_kuid(&init_user_ns, acl_e->e_uid));
			e += sizeof(ext4_acl_entry);
			break;
		case ACL_GROUP:
			entry->e_id = cpu_to_le32(
				from_kgid(&init_user_ns, acl_e->e_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(value, retval);
	else if (retval == -ENODATA || retval == -ENOSYS)
		acl = NULL;
	else
		acl = ERR_PTR(retval);
	kfree(value);

	if (!IS_ERR(acl))
		set_cached_acl(inode, type, acl);

	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 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;
		if (acl) {
			error = posix_acl_equiv_mode(acl, &inode->i_mode);
			if (error < 0)
				return error;
			else {
				inode->i_ctime = ext4_current_time(inode);
				ext4_mark_inode_dirty(handle, inode);
				if (error == 0)
					acl = NULL;
			}
		}
		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(acl, &size);
		if (IS_ERR(value))
			return (int)PTR_ERR(value);
	}

	error = ext4_xattr_set_handle(handle, inode, name_index, "",
				      value, size, 0);

	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, retries = 0;

retry:
	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
				    ext4_jbd2_credits_xattr(inode));
	if (IS_ERR(handle))
		return PTR_ERR(handle);

	error = __ext4_set_acl(handle, inode, type, acl);
	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);
		posix_acl_release(default_acl);
	}
	if (acl) {
		if (!error)
			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
					       acl);
		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
3dcf5451 CH	7	#include "ext4_jbd2.h"
3dcf5451 CH	8	#include "ext4.h"
ac27a0ec DK	9	#include "xattr.h"
	10	#include "acl.h"
	11
	12	/*
	13	* Convert from filesystem to in-memory representation.
	14	*/
	15	static struct posix_acl *
617ba13b	16	ext4_acl_from_disk(const void *value, size_t size)
ac27a0ec DK	17	{
	18	const char end = (char )value + size;
	19	int n, count;
	20	struct posix_acl *acl;
	21
	22	if (!value)
	23	return NULL;
617ba13b	24	if (size < sizeof(ext4_acl_header))
ac27a0ec	25	return ERR_PTR(-EINVAL);
617ba13b MC	26	if (((ext4_acl_header *)value)->a_version !=
617ba13b MC	27	cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec	28	return ERR_PTR(-EINVAL);
617ba13b MC	29	value = (char *)value + sizeof(ext4_acl_header);
617ba13b MC	30	count = ext4_acl_count(size);
ac27a0ec DK	31	if (count < 0)
	32	return ERR_PTR(-EINVAL);
	33	if (count == 0)
	34	return NULL;
216553c4	35	acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec DK	36	if (!acl)
ac27a0ec DK	37	return ERR_PTR(-ENOMEM);
2b2d6d01	38	for (n = 0; n < count; n++) {
617ba13b MC	39	ext4_acl_entry *entry =
	40	(ext4_acl_entry *)value;
	41	if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec DK	42	goto fail;
	43	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	44	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
2b2d6d01 TT	45
	46	switch (acl->a_entries[n].e_tag) {
	47	case ACL_USER_OBJ:
	48	case ACL_GROUP_OBJ:
	49	case ACL_MASK:
	50	case ACL_OTHER:
	51	value = (char *)value +
	52	sizeof(ext4_acl_entry_short);
2b2d6d01 TT	53	break;
	54
	55	case ACL_USER:
af84df93 EB	56	value = (char *)value + sizeof(ext4_acl_entry);
	57	if ((char *)value > end)
	58	goto fail;
	59	acl->a_entries[n].e_uid =
	60	make_kuid(&init_user_ns,
	61	le32_to_cpu(entry->e_id));
	62	break;
2b2d6d01 TT	63	case ACL_GROUP:
	64	value = (char *)value + sizeof(ext4_acl_entry);
	65	if ((char *)value > end)
ac27a0ec	66	goto fail;
af84df93 EB	67	acl->a_entries[n].e_gid =
	68	make_kgid(&init_user_ns,
	69	le32_to_cpu(entry->e_id));
2b2d6d01 TT	70	break;
	71
	72	default:
	73	goto fail;
ac27a0ec DK	74	}
	75	}
	76	if (value != end)
	77	goto fail;
	78	return acl;
	79
	80	fail:
	81	posix_acl_release(acl);
	82	return ERR_PTR(-EINVAL);
	83	}
	84
	85	/*
	86	* Convert from in-memory to filesystem representation.
	87	*/
	88	static void *
617ba13b	89	ext4_acl_to_disk(const struct posix_acl acl, size_t size)
ac27a0ec	90	{
617ba13b	91	ext4_acl_header *ext_acl;
ac27a0ec DK	92	char *e;
	93	size_t n;
	94
617ba13b MC	95	*size = ext4_acl_size(acl->a_count);
617ba13b MC	96	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	97	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	98	if (!ext_acl)
ac27a0ec DK	99	return ERR_PTR(-ENOMEM);
617ba13b MC	100	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	101	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	102	for (n = 0; n < acl->a_count; n++) {
af84df93	103	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
617ba13b	104	ext4_acl_entry entry = (ext4_acl_entry )e;
af84df93 EB	105	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	106	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	107	switch (acl_e->e_tag) {
2b2d6d01	108	case ACL_USER:
af84df93 EB	109	entry->e_id = cpu_to_le32(
	110	from_kuid(&init_user_ns, acl_e->e_uid));
	111	e += sizeof(ext4_acl_entry);
	112	break;
2b2d6d01	113	case ACL_GROUP:
af84df93 EB	114	entry->e_id = cpu_to_le32(
af84df93 EB	115	from_kgid(&init_user_ns, acl_e->e_gid));
2b2d6d01 TT	116	e += sizeof(ext4_acl_entry);
	117	break;
	118
	119	case ACL_USER_OBJ:
	120	case ACL_GROUP_OBJ:
	121	case ACL_MASK:
	122	case ACL_OTHER:
	123	e += sizeof(ext4_acl_entry_short);
	124	break;
	125
	126	default:
	127	goto fail;
ac27a0ec DK	128	}
	129	}
	130	return (char *)ext_acl;
	131
	132	fail:
	133	kfree(ext_acl);
	134	return ERR_PTR(-EINVAL);
	135	}
	136
ac27a0ec DK	137	/*
	138	* Inode operation get_posix_acl().
	139	*
	140	* inode->i_mutex: don't care
	141	*/
4e34e719	142	struct posix_acl *
617ba13b	143	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	144	{
ac27a0ec DK	145	int name_index;
	146	char *value = NULL;
	147	struct posix_acl *acl;
	148	int retval;
	149
2b2d6d01 TT	150	switch (type) {
2b2d6d01 TT	151	case ACL_TYPE_ACCESS:
2b2d6d01 TT	152	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	153	break;
2b2d6d01	154	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	155	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	156	break;
2b2d6d01	157	default:
073aaa1b	158	BUG();
ac27a0ec	159	}
617ba13b	160	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	161	if (retval > 0) {
216553c4	162	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	163	if (!value)
ac27a0ec DK	164	return ERR_PTR(-ENOMEM);
617ba13b	165	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	166	}
ac27a0ec DK	167	if (retval > 0)
617ba13b	168	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	169	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	170	acl = NULL;
	171	else
	172	acl = ERR_PTR(retval);
	173	kfree(value);
	174
073aaa1b AV	175	if (!IS_ERR(acl))
073aaa1b AV	176	set_cached_acl(inode, type, acl);
2b2d6d01	177
ac27a0ec DK	178	return acl;
	179	}
	180
	181	/*
	182	* Set the access or default ACL of an inode.
	183	*
617ba13b	184	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	185	*/
ac27a0ec DK	186	static int
64e178a7	187	__ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	188	struct posix_acl *acl)
ac27a0ec DK	189	{
ac27a0ec DK	190	int name_index;
	191	void *value = NULL;
	192	size_t size = 0;
	193	int error;
	194
2b2d6d01 TT	195	switch (type) {
	196	case ACL_TYPE_ACCESS:
	197	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	198	if (acl) {
d6952123	199	error = posix_acl_equiv_mode(acl, &inode->i_mode);
2b2d6d01 TT	200	if (error < 0)
	201	return error;
	202	else {
c6ac12a6	203	inode->i_ctime = ext4_current_time(inode);
2b2d6d01 TT	204	ext4_mark_inode_dirty(handle, inode);
	205	if (error == 0)
	206	acl = NULL;
ac27a0ec	207	}
2b2d6d01 TT	208	}
2b2d6d01 TT	209	break;
ac27a0ec	210
2b2d6d01 TT	211	case ACL_TYPE_DEFAULT:
	212	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	213	if (!S_ISDIR(inode->i_mode))
	214	return acl ? -EACCES : 0;
	215	break;
ac27a0ec	216
2b2d6d01 TT	217	default:
2b2d6d01 TT	218	return -EINVAL;
ac27a0ec DK	219	}
ac27a0ec DK	220	if (acl) {
617ba13b	221	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	222	if (IS_ERR(value))
	223	return (int)PTR_ERR(value);
	224	}
	225
617ba13b	226	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	227	value, size, 0);
	228
	229	kfree(value);
073aaa1b AV	230	if (!error)
073aaa1b AV	231	set_cached_acl(inode, type, acl);
2b2d6d01	232
ac27a0ec DK	233	return error;
	234	}
	235
ac27a0ec	236	int
64e178a7	237	ext4_set_acl(struct inode inode, struct posix_acl acl, int type)
ac27a0ec	238	{
bc26ab5f	239	handle_t *handle;
64e178a7	240	int error, retries = 0;
bc26ab5f	241
bc26ab5f	242	retry:
9924a92a	243	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
95eaefbd	244	ext4_jbd2_credits_xattr(inode));
64e178a7 CH	245	if (IS_ERR(handle))
	246	return PTR_ERR(handle);
	247
	248	error = __ext4_set_acl(handle, inode, type, acl);
bc26ab5f	249	ext4_journal_stop(handle);
64e178a7	250	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	251	goto retry;
ac27a0ec DK	252	return error;
	253	}
	254
	255	/*
64e178a7 CH	256	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
	257	*
	258	* dir->i_mutex: down
	259	* inode->i_mutex: up (access to inode is still exclusive)
ac27a0ec	260	*/
64e178a7 CH	261	int
64e178a7 CH	262	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec	263	{
64e178a7	264	struct posix_acl default_acl, acl;
ac27a0ec DK	265	int error;
ac27a0ec DK	266
64e178a7 CH	267	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	268	if (error)
	269	return error;
ac27a0ec	270
64e178a7 CH	271	if (default_acl) {
	272	error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
	273	default_acl);
	274	posix_acl_release(default_acl);
	275	}
	276	if (acl) {
	277	if (!error)
	278	error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
	279	acl);
	280	posix_acl_release(acl);
24ec19b0	281	}
ac27a0ec DK	282	return error;
ac27a0ec DK	283	}