[linux.git] / fs / ext4 / acl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/ext4/acl.c
 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 */

#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(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);

	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(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;
		if (mode != inode->i_mode)
			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);
	} else {
		inode->i_default_acl = NULL;
	}
	if (acl) {
		if (!error)
			error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
					       acl, XATTR_CREATE);
		posix_acl_release(acl);
	} else {
		inode->i_acl = NULL;
	}
	return error;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
ac27a0ec	2	/*
617ba13b	3	* linux/fs/ext4/acl.c
ac27a0ec DK	4	*
	5	* Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
	6	*/
	7
b8cb5a54	8	#include <linux/quotaops.h>
3dcf5451 CH	9	#include "ext4_jbd2.h"
3dcf5451 CH	10	#include "ext4.h"
ac27a0ec DK	11	#include "xattr.h"
	12	#include "acl.h"
	13
	14	/*
	15	* Convert from filesystem to in-memory representation.
	16	*/
	17	static struct posix_acl *
617ba13b	18	ext4_acl_from_disk(const void *value, size_t size)
ac27a0ec DK	19	{
	20	const char end = (char )value + size;
	21	int n, count;
	22	struct posix_acl *acl;
	23
	24	if (!value)
	25	return NULL;
617ba13b	26	if (size < sizeof(ext4_acl_header))
ac27a0ec	27	return ERR_PTR(-EINVAL);
617ba13b MC	28	if (((ext4_acl_header *)value)->a_version !=
617ba13b MC	29	cpu_to_le32(EXT4_ACL_VERSION))
ac27a0ec	30	return ERR_PTR(-EINVAL);
617ba13b MC	31	value = (char *)value + sizeof(ext4_acl_header);
617ba13b MC	32	count = ext4_acl_count(size);
ac27a0ec DK	33	if (count < 0)
	34	return ERR_PTR(-EINVAL);
	35	if (count == 0)
	36	return NULL;
216553c4	37	acl = posix_acl_alloc(count, GFP_NOFS);
ac27a0ec DK	38	if (!acl)
ac27a0ec DK	39	return ERR_PTR(-ENOMEM);
2b2d6d01	40	for (n = 0; n < count; n++) {
617ba13b MC	41	ext4_acl_entry *entry =
	42	(ext4_acl_entry *)value;
	43	if ((char *)value + sizeof(ext4_acl_entry_short) > end)
ac27a0ec DK	44	goto fail;
	45	acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
	46	acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
2b2d6d01 TT	47
	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(ext4_acl_entry_short);
2b2d6d01 TT	55	break;
	56
	57	case ACL_USER:
af84df93 EB	58	value = (char *)value + sizeof(ext4_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;
2b2d6d01 TT	65	case ACL_GROUP:
	66	value = (char *)value + sizeof(ext4_acl_entry);
	67	if ((char *)value > end)
ac27a0ec	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));
2b2d6d01 TT	72	break;
	73
	74	default:
	75	goto fail;
ac27a0ec DK	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 *
617ba13b	91	ext4_acl_to_disk(const struct posix_acl acl, size_t size)
ac27a0ec	92	{
617ba13b	93	ext4_acl_header *ext_acl;
ac27a0ec DK	94	char *e;
	95	size_t n;
	96
617ba13b MC	97	*size = ext4_acl_size(acl->a_count);
617ba13b MC	98	ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
216553c4	99	sizeof(ext4_acl_entry), GFP_NOFS);
ac27a0ec DK	100	if (!ext_acl)
ac27a0ec DK	101	return ERR_PTR(-ENOMEM);
617ba13b MC	102	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
617ba13b MC	103	e = (char *)ext_acl + sizeof(ext4_acl_header);
2b2d6d01	104	for (n = 0; n < acl->a_count; n++) {
af84df93	105	const struct posix_acl_entry *acl_e = &acl->a_entries[n];
617ba13b	106	ext4_acl_entry entry = (ext4_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) {
2b2d6d01	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(ext4_acl_entry);
	114	break;
2b2d6d01	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));
2b2d6d01 TT	118	e += sizeof(ext4_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(ext4_acl_entry_short);
	126	break;
	127
	128	default:
	129	goto fail;
ac27a0ec DK	130	}
	131	}
	132	return (char *)ext_acl;
	133
	134	fail:
	135	kfree(ext_acl);
	136	return ERR_PTR(-EINVAL);
	137	}
	138
ac27a0ec DK	139	/*
	140	* Inode operation get_posix_acl().
	141	*
	142	* inode->i_mutex: don't care
	143	*/
4e34e719	144	struct posix_acl *
617ba13b	145	ext4_get_acl(struct inode *inode, int type)
ac27a0ec	146	{
ac27a0ec DK	147	int name_index;
	148	char *value = NULL;
	149	struct posix_acl *acl;
	150	int retval;
	151
2b2d6d01 TT	152	switch (type) {
2b2d6d01 TT	153	case ACL_TYPE_ACCESS:
2b2d6d01 TT	154	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01 TT	155	break;
2b2d6d01	156	case ACL_TYPE_DEFAULT:
2b2d6d01 TT	157	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
2b2d6d01 TT	158	break;
2b2d6d01	159	default:
073aaa1b	160	BUG();
ac27a0ec	161	}
617ba13b	162	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
ac27a0ec	163	if (retval > 0) {
216553c4	164	value = kmalloc(retval, GFP_NOFS);
ac27a0ec DK	165	if (!value)
ac27a0ec DK	166	return ERR_PTR(-ENOMEM);
617ba13b	167	retval = ext4_xattr_get(inode, name_index, "", value, retval);
ac27a0ec DK	168	}
ac27a0ec DK	169	if (retval > 0)
617ba13b	170	acl = ext4_acl_from_disk(value, retval);
ac27a0ec DK	171	else if (retval == -ENODATA \|\| retval == -ENOSYS)
	172	acl = NULL;
	173	else
	174	acl = ERR_PTR(retval);
	175	kfree(value);
	176
ac27a0ec DK	177	return acl;
	178	}
	179
	180	/*
	181	* Set the access or default ACL of an inode.
	182	*
617ba13b	183	* inode->i_mutex: down unless called from ext4_new_inode
ac27a0ec DK	184	*/
ac27a0ec DK	185	static int
64e178a7	186	__ext4_set_acl(handle_t handle, struct inode inode, int type,
af65207c	187	struct posix_acl *acl, int xattr_flags)
ac27a0ec	188	{
ac27a0ec DK	189	int name_index;
	190	void *value = NULL;
	191	size_t size = 0;
	192	int error;
	193
2b2d6d01 TT	194	switch (type) {
	195	case ACL_TYPE_ACCESS:
	196	name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
2b2d6d01	197	break;
ac27a0ec	198
2b2d6d01 TT	199	case ACL_TYPE_DEFAULT:
	200	name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
	201	if (!S_ISDIR(inode->i_mode))
	202	return acl ? -EACCES : 0;
	203	break;
ac27a0ec	204
2b2d6d01 TT	205	default:
2b2d6d01 TT	206	return -EINVAL;
ac27a0ec DK	207	}
ac27a0ec DK	208	if (acl) {
617ba13b	209	value = ext4_acl_to_disk(acl, &size);
ac27a0ec DK	210	if (IS_ERR(value))
	211	return (int)PTR_ERR(value);
	212	}
	213
617ba13b	214	error = ext4_xattr_set_handle(handle, inode, name_index, "",
af65207c	215	value, size, xattr_flags);
ac27a0ec DK	216
ac27a0ec DK	217	kfree(value);
397e4341	218	if (!error) {
073aaa1b	219	set_cached_acl(inode, type, acl);
397e4341	220	}
2b2d6d01	221
ac27a0ec DK	222	return error;
	223	}
	224
ac27a0ec	225	int
64e178a7	226	ext4_set_acl(struct inode inode, struct posix_acl acl, int type)
ac27a0ec	227	{
bc26ab5f	228	handle_t *handle;
c1a5d5f6 TE	229	int error, credits, retries = 0;
c1a5d5f6 TE	230	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
a3bb2d55 JK	231	umode_t mode = inode->i_mode;
a3bb2d55 JK	232	int update_mode = 0;
bc26ab5f	233
b8cb5a54 TE	234	error = dquot_initialize(inode);
	235	if (error)
	236	return error;
bc26ab5f	237	retry:
af65207c TE	238	error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
af65207c TE	239	&credits);
dec214d0 TE	240	if (error)
	241	return error;
	242
c1a5d5f6	243	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
64e178a7 CH	244	if (IS_ERR(handle))
	245	return PTR_ERR(handle);
	246
a3bb2d55 JK	247	if ((type == ACL_TYPE_ACCESS) && acl) {
	248	error = posix_acl_update_mode(inode, &mode, &acl);
	249	if (error)
	250	goto out_stop;
0a1e8258 CX	251	if (mode != inode->i_mode)
0a1e8258 CX	252	update_mode = 1;
a3bb2d55 JK	253	}
a3bb2d55 JK	254
af65207c	255	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
a3bb2d55 JK	256	if (!error && update_mode) {
	257	inode->i_mode = mode;
	258	inode->i_ctime = current_time(inode);
	259	ext4_mark_inode_dirty(handle, inode);
	260	}
	261	out_stop:
bc26ab5f	262	ext4_journal_stop(handle);
64e178a7	263	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
bc26ab5f	264	goto retry;
ac27a0ec DK	265	return error;
	266	}
	267
	268	/*
64e178a7 CH	269	* Initialize the ACLs of a new inode. Called from ext4_new_inode.
	270	*
	271	* dir->i_mutex: down
	272	* inode->i_mutex: up (access to inode is still exclusive)
ac27a0ec	273	*/
64e178a7 CH	274	int
64e178a7 CH	275	ext4_init_acl(handle_t handle, struct inode inode, struct inode *dir)
ac27a0ec	276	{
64e178a7	277	struct posix_acl default_acl, acl;
ac27a0ec DK	278	int error;
ac27a0ec DK	279
64e178a7 CH	280	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
	281	if (error)
	282	return error;
ac27a0ec	283
64e178a7 CH	284	if (default_acl) {
64e178a7 CH	285	error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
af65207c	286	default_acl, XATTR_CREATE);
64e178a7	287	posix_acl_release(default_acl);
6fd94178 CX	288	} else {
6fd94178 CX	289	inode->i_default_acl = NULL;
64e178a7 CH	290	}
	291	if (acl) {
	292	if (!error)
	293	error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
af65207c	294	acl, XATTR_CREATE);
64e178a7	295	posix_acl_release(acl);
6fd94178 CX	296	} else {
6fd94178 CX	297	inode->i_acl = NULL;
24ec19b0	298	}
ac27a0ec DK	299	return error;
ac27a0ec DK	300	}