[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(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 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_update_mode(inode, &inode->i_mode, &acl);
			if (error)
				return error;
			inode->i_ctime = current_time(inode);
			ext4_mark_inode_dirty(handle, inode);
		}
		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, 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 *
acc94812	16	ext4_acl_from_disk(struct super_block sb, 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 =
acc94812	60	make_kuid(sb->s_user_ns,
af84df93	61	le32_to_cpu(entry->e_id));
acc94812 SF	62	if (!uid_valid(acl->a_entries[n].e_uid))
acc94812 SF	63	goto fail;
af84df93	64	break;
2b2d6d01 TT	65	case ACL_GROUP:
	66	value = (char *)value + sizeof(ext4_acl_entry);
	67	if ((char *)value > end)
ac27a0ec	68	goto fail;
af84df93	69	acl->a_entries[n].e_gid =
acc94812	70	make_kgid(sb->s_user_ns,
af84df93	71	le32_to_cpu(entry->e_id));
acc94812 SF	72	if (!gid_valid(acl->a_entries[n].e_gid))
acc94812 SF	73	goto fail;
2b2d6d01 TT	74	break;
	75
	76	default:
	77	goto fail;
ac27a0ec DK	78	}
	79	}
	80	if (value != end)
	81	goto fail;
	82	return acl;
	83
	84	fail:
	85	posix_acl_release(acl);
	86	return ERR_PTR(-EINVAL);
	87	}
	88
	89	/*
	90	* Convert from in-memory to filesystem representation.
	91	*/
	92	static void *
acc94812 SF	93	ext4_acl_to_disk(struct super_block sb, const struct posix_acl acl,
acc94812 SF	94	size_t *size)
ac27a0ec	95	{
617ba13b	96	ext4_acl_header *ext_acl;
ac27a0ec DK	97	char *e;
ac27a0ec DK	98	size_t n;
acc94812 SF	99	uid_t uid;
acc94812 SF	100	gid_t gid;
ac27a0ec	101
617ba13b MC	102	*size = ext4_acl_size(acl->a_count);
617ba13b MC	103	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	104	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	105	if (!ext_acl)
ac27a0ec DK	106	return ERR_PTR(-ENOMEM);
617ba13b MC	107	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	108	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	109	for (n = 0; n < acl->a_count; n++) {
af84df93	110	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
617ba13b	111	ext4_acl_entry entry = (ext4_acl_entry )e;
af84df93 EB	112	entry->e_tag = cpu_to_le16(acl_e->e_tag);
	113	entry->e_perm = cpu_to_le16(acl_e->e_perm);
	114	switch (acl_e->e_tag) {
2b2d6d01	115	case ACL_USER:
acc94812 SF	116	uid = from_kuid(sb->s_user_ns, acl_e->e_uid);
	117	if (uid == (uid_t)-1)
	118	goto fail;
	119	entry->e_id = cpu_to_le32(uid);
af84df93 EB	120	e += sizeof(ext4_acl_entry);
af84df93 EB	121	break;
2b2d6d01	122	case ACL_GROUP:
acc94812 SF	123	gid = from_kgid(sb->s_user_ns, acl_e->e_gid);
	124	if (gid == (gid_t)-1)
	125	goto fail;
	126	entry->e_id = cpu_to_le32(gid);
2b2d6d01 TT	127	e += sizeof(ext4_acl_entry);
	128	break;
	129
	130	case ACL_USER_OBJ:
	131	case ACL_GROUP_OBJ:
	132	case ACL_MASK:
	133	case ACL_OTHER:
	134	e += sizeof(ext4_acl_entry_short);
	135	break;
	136
	137	default:
	138	goto fail;
ac27a0ec DK	139	}
	140	}
	141	return (char *)ext_acl;
	142
	143	fail:
	144	kfree(ext_acl);
	145	return ERR_PTR(-EINVAL);
	146	}
	147
ac27a0ec DK	148	/*
	149	* Inode operation get_posix_acl().
	150	*
	151	* inode->i_mutex: don't care
	152	*/
4e34e719	153	struct posix_acl *
617ba13b	154	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	155	{
ac27a0ec DK	156	int name_index;
	157	char *value = NULL;
	158	struct posix_acl *acl;
	159	int retval;
	160
2b2d6d01 TT	161	switch (type) {
2b2d6d01 TT	162	case ACL_TYPE_ACCESS:
2b2d6d01 TT	163	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	164	break;
2b2d6d01	165	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	166	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	167	break;
2b2d6d01	168	default:
073aaa1b	169	BUG();
ac27a0ec	170	}
617ba13b	171	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	172	if (retval > 0) {
216553c4	173	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	174	if (!value)
ac27a0ec DK	175	return ERR_PTR(-ENOMEM);
617ba13b	176	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	177	}
ac27a0ec DK	178	if (retval > 0)
acc94812	179	acl = ext4_acl_from_disk(inode->i_sb, value, retval);
ac27a0ec DK	180	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	181	acl = NULL;
	182	else
	183	acl = ERR_PTR(retval);
	184	kfree(value);
	185
ac27a0ec DK	186	return acl;
	187	}
	188
	189	/*
	190	* Set the access or default ACL of an inode.
	191	*
617ba13b	192	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	193	*/
ac27a0ec DK	194	static int
64e178a7	195	__ext4_set_acl(handle_t handle, struct inode inode, int type,
ac27a0ec DK	196	struct posix_acl *acl)
ac27a0ec DK	197	{
ac27a0ec DK	198	int name_index;
	199	void *value = NULL;
	200	size_t size = 0;
	201	int error;
	202
2b2d6d01 TT	203	switch (type) {
	204	case ACL_TYPE_ACCESS:
	205	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
	206	if (acl) {
07393101 JK	207	error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
07393101 JK	208	if (error)
2b2d6d01	209	return error;
eeca7ea1	210	inode->i_ctime = current_time(inode);
07393101	211	ext4_mark_inode_dirty(handle, inode);
2b2d6d01 TT	212	}
2b2d6d01 TT	213	break;
ac27a0ec	214
2b2d6d01 TT	215	case ACL_TYPE_DEFAULT:
	216	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	217	if (!S_ISDIR(inode->i_mode))
	218	return acl ? -EACCES : 0;
	219	break;
ac27a0ec	220
2b2d6d01 TT	221	default:
2b2d6d01 TT	222	return -EINVAL;
ac27a0ec DK	223	}
ac27a0ec DK	224	if (acl) {
acc94812	225	value = ext4_acl_to_disk(inode->i_sb, acl, &size);
ac27a0ec DK	226	if (IS_ERR(value))
	227	return (int)PTR_ERR(value);
	228	}
	229
617ba13b	230	error = ext4_xattr_set_handle(handle, inode, name_index, "",
ac27a0ec DK	231	value, size, 0);
	232
	233	kfree(value);
073aaa1b AV	234	if (!error)
073aaa1b AV	235	set_cached_acl(inode, type, acl);
2b2d6d01	236
ac27a0ec DK	237	return error;
	238	}
	239
ac27a0ec	240	int
64e178a7	241	ext4_set_acl(struct inode inode, struct posix_acl acl, int type)
ac27a0ec	242	{
bc26ab5f	243	handle_t *handle;
64e178a7	244	int error, retries = 0;
bc26ab5f	245
bc26ab5f	246	retry:
9924a92a	247	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
95eaefbd	248	ext4_jbd2_credits_xattr(inode));
64e178a7 CH	249	if (IS_ERR(handle))
	250	return PTR_ERR(handle);
	251
	252	error = __ext4_set_acl(handle, inode, type, acl);
bc26ab5f	253	ext4_journal_stop(handle);
64e178a7	254	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	255	goto retry;
ac27a0ec DK	256	return error;
	257	}
	258
	259	/*
64e178a7 CH	260	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
	261	*
	262	* dir->i_mutex: down
	263	* inode->i_mutex: up (access to inode is still exclusive)
ac27a0ec	264	*/
64e178a7 CH	265	int
64e178a7 CH	266	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec	267	{
64e178a7	268	struct posix_acl default_acl, acl;
ac27a0ec DK	269	int error;
ac27a0ec DK	270
64e178a7 CH	271	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	272	if (error)
	273	return error;
ac27a0ec	274
64e178a7 CH	275	if (default_acl) {
	276	error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
	277	default_acl);
	278	posix_acl_release(default_acl);
	279	}
	280	if (acl) {
	281	if (!error)
	282	error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
	283	acl);
	284	posix_acl_release(acl);
24ec19b0	285	}
ac27a0ec DK	286	return error;
ac27a0ec DK	287	}